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COSMOS: A Sketch of the Physical Description of the Universe, Vol. 1
by Alexander von Humboldt
Translated by E C Otte
from the 1858 Harper & Brothers edition of Cosmos, volume 1
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p i
COSMOS
VOLUME I
[p ii is blank]
[p iii - not copied; pertains to reprint series]
p iv [portrait]
p v
COSMOS
A SKETCH
OR
A PHYSICAL DESCRIPTION OF THE UNIVERSE
BY
ALEXANDER VON HUMBOLDT
TRANSLATED FROM THE GERMAN
BY E. C. OTTE
Naturae vero rerum vis atque majestas in omnibus momentis fides caret, si
quis modo partes ejus ac non totam complectatur animo. -- Plin., 'Hist.
Nat.', lib. vii, c. 1.
VOLUME I
WITH AN INTRODUCTION
BY NICOLAAS A. RUPKE
THE JOHNS HOPKINS UNIVERSITY PRESS
Baltimore and London
[page vi and Introduction to the 1997 edition not copied]
p 1
COSMOS
VOLUME I
[p 2 is blank]
p 3
TRANSLATOR'S PREFACE.
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I CAN not more appropriately introduce the Cosmos than by presenting a brief
sketch of the life of its illustrious author.* While the name of Alexander
von Humboldt is familiar to every one, few, perhaps, are aware of the
peculiar circumstances of his scientific career and of the extent of his
labors in almost every department of physical knowledge. He was born on the
14th of September, 1769, and is, therefore, now in his 80th year. After
going through the ordinary course of education at Gottingen, and having made
a rapid tour through Holland, England, and France, he became a pupil of
Werner at the mining school of Freyburg, and in his 21st year published an
"Essay on the Basalts of the Rhine." Though he soon became officially
connected with the mining corps, he was enabled to continue his excursions
in foreign countries, for, during the six or seven years succeeding the
publication of his first essay, he seems to have visited Austria,
Switzerland, Italy, and France. His attention to mining did not, however,
prevent him from devoting his attention to other scientific pursuits, among
which botany and the then recent discovery of galvanism may be especially
noticed. Botany, indeed, we know from his own authority, occupied him
almost exclusively for some years; but even at this time he was practicing
the use of those astronomical and physical instruments which he afterward
turned to so singularly excellent an account.
[footnote] *For the following remarks I am mainly indebted to the articles
on the Cosmos in the two leading Quarterly Reviews.
The political disturbances of the civilized world at the close
p 4
of the last century prevented our author from carrying out various plans of
foreign travel which he had contemplated, and detained him an unwilling
prisoner in Europe. In the year 1799 he went to Spain, with the hope of
entering Africa from Cadiz, but the unexpected patronage which he received
at the court of Madrid led to a great alteration in his plans, and decided
him to proceed directly to the Spanish possessions in America, "and there
gratify the longings for foreign adventure, and the scenery of the tropics,
which had haunted him from boyhood, but had all along been turned in the
diametrically opposite direction of Asia." After encountering various risks
of capture, he succeeded in reaching America, and from 1799 to 1804
prosecuted there extensive researches in the physical geography of the New
World, which has indelibly stamped his name in the undying records of
science.
Excepting an excursion to Naples with Gay-Lussac and Von Buch in 1805 (the
year after his return from America), the succeeding twenty years of his life
were spent in Paris, and were almost exclusively employed in editing the
results of his American journey. In order to bring these results before the
world in a manner worthy of their importance, he commenced a series of
gigantic publications in almost every branch of science on which he had
instituted observations. In 1817, after twelve years of incessant toil,
four fifths were completed, and an ordinary copy of the part then in print
cost considerably more than one hundred pounds sterling. Since that time
the publication has gone on more slowly, and even now after the lapse of
nearly half a century, it remains, and probably ever will remain, incomplete.
In the year 1828, when the greatest portion of his literary labor had been
accomplished, he undertook a scientific journey to Siberia, under the
special protection of the Russian government. In this journey -- a journey
for which he had prepared himself by a course of study unparalleled in the
history of travel -- he was accompanied by two companions hardly less
distinguished than himself, Ehrenberg and Gustav Rose, and
p 5
the results obtained during their expedition are recorded by our author in
his 'Fragments Asiatiques', and in his 'Asie Centrale', and by Rose in his
'Reise nach dem Oural'. If the 'Asie Centrale' had been his only work,
constituting, as it does, an epitome of all the knowledge acquired by
himself and by former travelers on the physical geography of Northern and
Central Asia, that work alone would have sufficed to form a reputation of
the highest order.
I proceed to offer a few remarks on the work of which I now present a new
translation to the English public, a work intended by its author "to embrace
a summary of physical knowledge, as connected with a delineation of the
material universe."
The idea of such a physical description of the universe had, it appears,
been present to his mind from a very early epoch. It was a work which he
felt he must accomplish, and he devoted almost a lifetime to the
accumulation of materials for it. For almost half a century it had occupied
his thoughts; and at length, in the evening of life, he felt himself rich
enough in the accumulation of thought, travel, reading, and experimental
research, to reduce into form and reality the undefined vision that has so
long floated before him. The work, when completed, will form three volumes.
The 'first' volume comprises a sketch of all that is at present known of
the physical phenomena of the universe; the 'second' comprehends two
distinct parts, the first of which treats of the incitements to the study of
nature, afforded in descriptive poetry, landscape painting, and the
cultivation of exotic plants; while the second and larger part enters into
the consideration of the different epochs in the progress of discovery and
of the corresponding stages of advance in human civilization. The 'third'
volume, the publication of which, as M. Humboldt himself informs me in a
letter addressed to my learned friend and publisher, Mr. H. G. Bohn, "has
been somewhat delayed, owing to the present state of public affairs, will
comprise the special and scientific development of the great Picture of
Nature
p 6
Each of the three parts of the 'Cosmos' is therefore, to a certain extent,
distinct in its object, and may be considered complete in itself. We can
not better terminate this brief notice than in the words of one of the most
eminent philosophers of our own country, that, "should the conclusion
correspond (as we doubt not) with these beginnings, a work will have been
accomplished every way worthy of the author's fame, and a crowning laurel
added to that wreath with which Europe will always delight to surround the
name of Alexander von Humboldt."
In venturing to appear before the English public as the interpreter of "the
great work of our age,"* I have been encouraged by the assistance of many
kind literary and scientific friends, and I gladly avail myself of this
opportunity of expressing my deep obligations to Mr. Brooke, Dr. Day,
Professor Edward Forbes, Mr. Hind, Mr. Glaisher, Dr. Percy, and Mr. Ronalds,
for the valuable aid they have afforded me.
[footnote] *The expression applied to the Cosmos by the learned Bunsen, in
his late Report on Ethnology, in the 'Report of the British Association for'
1847, p. 265.
It would be scarcely right to conclude these remarks without a reference to
the translations that have preceded mine. The translation executed by Mrs.
Sabine is singularly accurate and elegant. The other translation is
remarkable for the opposite qualities, and may therefore be passed over in
silence. The present volumes differ from those of Mrs. Sabine in having all
the foreign measures converted into corresponding English terms, in being
published at considerably less than one third of the price, and in being a
translation of the entire work, for I have not conceived myself justified in
omitting passages, sometimes amounting to pages, simply because they might
be deemed slightly obnoxious to our national prejudices.
p 7
AUTHOR'S PREFACE.
-------------------
In the late evening of an active life I offer to the German public a work,
whose undefined image has floated before my mind for almost half a century.
I have frequently looked upon its completion as impracticable, but as often
as I have been disposed to relinquish the undertaking, I have again --
although perhaps imprudently -- resumed the task. This work I now present
to my contemporaries with a diffidence inspired by a just mistrust of my own
powers, while I would willingly forget that writings long expected are
usually received with less indulgence.
Although the outward relations of life, and an irresistible impulse toward
knowledge of various kinds, have led me to occupy myself for many years --
and apparently exclusively -- with separate branches of science, as, for
instance, with descriptive botany, geognosy, chemistry, astronomical
determinations of position, and terrestrial magnetism, in order that I might
the better prepare myself for the extensive travels in which I was desirous
of engaging, the actual object of my studies has nevertheless been of a
higher character. The principal impulse by which I was directed was the
earnest endeavor to comprehend the phenomena of physical objects in their
general connection, and to represent nature as one great whole, moved and
animated by internal forces. My intercourse with highly-gifted men early
led me to discover that, without an earnest striving to attain to a
knowledge of special branches of study, all attempts to give a grand and
general view of the universe would be nothing more than a vain illusion.
These special departments in the great domain of natural
p 8
science are, moreover, capable of being reciprocally fructified by means of
the appropriative forces by which they are endowed. Descriptive botany, no
longer confined to the narrow circle of the determination of genera and
species, leads the observer who traverses distant lands and lofty mountains
to the study of the geographical distribution of plants of the earth's
surface, according to distance from the equator and vertical elevation above
the sea. It is further necessary to investigate the laws which regulate the
differences of temperature and climate, and the meteorological processes of
the atmosphere, before we can hope to explain the involved causes of
vegetable distribution; and it is thus that the observer who earnestly
pursues the path of knowledge is led from one class of phenomena to another,
by means of the mutual dependence and connection existing between them.
I have enjoyed an advantage which few scientific travelers have shared to an
equal extent, viz., that of having seen not only littoral districts, such as
are alone visited by the majority of those who take part in voyages of
circumnavigation, but also those portions of the interior of two vast
continents which present the most striking contrasts manifested in the
Alpine tropical landscapes of South America, and the dreary wastes of the
steppes in Northern Asia. Travels, undertaken in districts such as these,
could not fail to encourage the natural tendency of my mind toward a
generalization of views, and to encourage me to attempt, in a special work,
to treat of the knowledge which we at present possess, regarding the
sidereal and terrestrial phenomena of the Cosmos in their empirical
relations. The hitherto undefined idea of a physical geography has thus, by
an extended and perhaps too boldly imagined a plan, been comprehended under
the idea of a physical description of the universe, embracing all created
things in the regions of space and in the earth.
The very abundance of the materials which are presented to the mind for
arrangement and definition, necessarily impart no inconsiderable
difficulties in the choice of the form under
p 9
which such a work must be presented, if it would aspire to the honor of
being regarded as a literary composition. Descriptions of nature ought not
to be deficient in a tone of life-like truthfulness, while the mere
enumeration of a series of general results is productive of a no less
wearying impression than the elaborate accumulation of the individual data
of observation. I scarcely venture to hope that I have succeeded in
satisfying these various requirements of composition, or that I have myself
avoided the shoals and breakers which I have known how to indicate to
others. My faint hope of success rests upon the special indulgence which
the German public have bestowed upon a small work bearing the title of
'Ansichten der Natur', which I published soon after my return from Mexico.
This work treats, under general points of view, of separate branches of
physical geography (such as the forms of vegetation, grassy plains, and
deserts). The effect produced by this small volume has doubtlessly been
more powerfully manifested in the influence it has exercised on the
sensitive minds of the young, whose imaginative faculties are so strongly
manifested, than by means of any thing which it could itself impart. In the
work on the Cosmos on which I am now engaged, I have endeavored to show, as
in that entitled 'Ansichten der Natur', that a certain degree of scientific
completeness in the treatment of individual facts is not wholly incompatible
with a picturesque animation of style.
Since public lectures seemed to me to present an easy and efficient means of
testing the more or less successful manner of connecting together the
detached branches of any one science, I undertook, for many months
consecutively, first in the French language, at Paris, and afterward in my
own native German, at Berlin (almost simultaneously at two different places
of assembly), to deliver a course of lectures on the physical description of
the universe, according to my conception of the science. My lectures were
given extemporaneously, both in French and German, and without the aid of
written notes, nor have I, in any way, made use, in the present work,
p 10
of those portions of my discourses which have been preserved by the industry
of certain attentive auditors. With the exception of the first forty pages,
the whole of the present work was written, for the first time, in the years
1843 and 1844.
A character of unity, freshness, and animation must, I think, be derived
from an association with some definite epoch, where the object of the writer
is to delineate the present condition of knowledge and opinions. Since the
additions constantly made to the latter give rise to fundamental changes in
pre-existing views, my lectures and the Cosmos have nothing in common beyond
the succession in which the various facts are treated. The first portion of
my work contains introductory considerations regarding the diversity in the
degrees of enjoyment to be derived from nature, and the knowledge of the
laws by which the universe is governed; it also considers the limitation and
scientific mode of treating a physical description of the universe, and
gives a general picture of nature which contains a view of all the phenomena
comprised in the Cosmos.
This general picture of nature, which embraces within its wide scope the
remotest nebulous spots, and the revolving double stars in the regions of
space, no less than the telluric phenomena included under the department of
the geography of organic forms (such as plants, animals, and races of men),
comprises all that I deem most specially important with regard to the
connection existing between generalities and specialities, while it moreover
exemplifies, by the form and style of the composition, the mode of treatment
pursued in the selection of the results obtained from experimental
knowledge. The two succeeding volumes will contain a consideration of the
particular means of incitement toward the study of nature (consisting in
animated delineations, landscape painting, and the arrangement and
cultivation of exotic vegetable forms), of the history of the contemplation
of the universe, or the gradual development of the reciprocal action of
natural forces constituting one natural whole; and lastly, of the special
p 11
branches of the several departments of science, whose mutual connection is
indicated in the beginning of the work. Wherever it has been possible to do
so, I have adduced the authorities from whence I derived my facts, with a
view of affording testimony both to the accuracy of my statements and to the
value of the observations to which reference was made. In those instances
where I have quoted from my own writings (the facts contained in which
being, from their very nature, scattered through different portions of my
works), I have always referred to the original editions, owing to the
importance of accuracy with regard to numerical relations, and to my own
distrust of the care and correctness of translators. In the few cases where
I have extracted short passages from the works of my friends, I have
indicated them by marks of quotation; and, in imitation of the practice of
the ancients, I have invariably preferred the repetition of the same words
to any arbitrary substitution of my own paraphrases. The much-contested
question of priority of claim to a first discovery, which it is so dangerous
to treat of in a work of this uncontroversial kind, has rarely been touched
upon. Where I have occasionally referred to classical antiquity, and to
that happy period of transition which has rendered the sixteenth and
seventeenth centuries so celebrated, owing to the great geographical
discoveries by which the age was characterized, I have been simply led to
adopt this mode of treatment, from the desire we experience from time to
time, when considering the general views of nature, to escape from the
circle of more strictly dogmatical modern opinions, and enter the free and
fanciful domain of earlier presentiments.
It has frequently been regarded as a subject of discouraging consideration,
that while purely literary products of intellectual activity are rooted in
the depths of feeling, and interwoven with the creative force of
imagination, all works treating of empirical knowledge, and of the
connection of natural phenomena and physical laws, are subject to the most
marked modifications of form in the lapse of short periods of time, both
p 12
by the improvement in the instruments used, and by the consequent expansion
of the field of view opened to rational observation, and that those
scientific works which have, to use a common expression, become 'antiquated'
by the acquisition of new funds of knowledge, are thus continually being
consigned to oblivion as unreadable. However discouraging such a prospect
must be, no one who is animated by a genuine love of nature, and by a sense
of the dignity attached to its study, can view with regret any thing which
promises future additions and a greater degree of perfection to general
knowledge. Many important branches of knowledge have been based upon a
solid foundation which will not easily be shaken, both as regards the
phenomena in the regions of space and on the earth; while there are other
portions of science in which general views will undoubtedly take the place
of merely special; where new forces will be discovered and new substances
will be made known, and where those which are now considered as simple will
be decomposed. I would, therefore, venture to hope that an attempt to
delineate nature in all its vivid animation and exalted grandeur, and to
trace the 'stable' amid the vacillating, ever-recurring alternation of
physical metamorphoses, will not be wholly disregarded even at a future age.
'Potsdam, Nov.', 1844.
This material taken from pages 13-22
NB - The page numbers will be properly aligned in Courier 12 font.
COSMOS: A Sketch of the Physical Description of the Universe, Vol. 1
by Alexander von Humboldt
Translated by E C Otte
from the 1858 Harper & Brothers edition of Cosmos, volume 1
--------------------------------------------------
p 13
CONTENTS OF VOL. I.
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Page
The Translator's Preface . . . . . . . . . . . . . . . . . . . . . .3
The Author's Preface . . . . . . . . . . . . . . . . . . . . . . . .7
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
INTRODUCTION.
The Results of the Study of Physical Phenomena . . . . . . . . . . 23
The different Epochs of the Contemplation of the external World . .24
The different Degrees of Enjoyment presented by the Contemplation
of Nature . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Instances of this Species of Enjoyment . . . . . . . . . . . . . . 26
Means by which it is induced . . . . . . . . . . . . . . . . . . . 26
The Elevations and climatic Relations of many of the most
celebrated Mountains in the World, considered with
Reference to the Effect produced on the Mind of the
Observer . . . . . . . . . . . . . . . . . . . . . . . . . .27-33
The Impressions awakened by the Aspect of tropical Regions . . . . 34
The more accurate Knowledge of the Physical Forces of the
Universe, acquired by the Inhabitants of a small Section
of the temperate Zone . . . . . . . . . . . . . . . . . . . . .36
The earliest Dawn of the Science of the Cosmos . . . . . . . . . . 36
The Difficulties that opposed the Progress of Inquiry . . . . . . . 37
Consideration of the Effect produced on the Mind by the
Observation of Nature, and the Fear entertained by some of
its injurious Influence . . . . . . . . . . . . . . . . . . . 40
Illustrations of the Manner in which many recent Discoveries have
tended to Remove the groundless Fears entertained
regarding the Agency of certain Natural Phenomena . . . . . . 43
The Amount of Scientific Knowledge required to enter on the
Consideration of Physical Phenomena . . . . . . . . . . . . . 47
The Object held in View by the present Work . . . . . . . . . . . . 49
The Nature of the Study of the Cosmos . . . . . . . . . . . . . . . 50
The special Requirements of the present Age . . . . . . . . . . . . 53
Limits and Method of Exposition of the Physical Description of the
Universe . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Considerations on the terms Physiology and Physics . . . . . . . . .58
Physical Geography . . . . . . . . . . . . . . . . . . . . . . . . 59
Celestial Phenomena . . . . . . . . . . . . . . . . . . . . . . . . 63
The Natural Philosophy of the Ancients directed more to Celestial
than to Terrestrial Phenomena . . . . . . . . . . . . . . . . .65
The able Treatises of Varenius and Carl Ritter . . . . . . . . .66, 67
Signification of the Word Cosmos . . . . . . . . . . . . . . . . 68-70
The Domain embraced by Cosmography . . . . . . . . . . . . . . . . 71
Empiricism and Experiments . . . . . . . . . . . . . . . . . . . . 74
The Process of Reason and Induction . . . . . . . . . . . . . . . .77
p 14
GENERAL REVIEW OF NATURAL PHENOMENA.
Connection between the Material and the Ideal World . . . . . . . . 80
Delineation of Nature . . . . . . . . . . . . . . . . . . . . . . . 82
Celestial Phenomena . . . . . . . . . . . . . . . . . . . . . . . . 83
Sidereal Systems . . . . . . . . . . . . . . . . . . . . . . . . . 89
Planetary Systems . . . . . . . . . . . . . . . . . . . . . . . . .90
Comets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
Aerolites . . . . . . . . . . . . . . . . . . . . . . . . . . . . .111
Zodiacal Light . . . . . . . . . . . . . . . . . . . . . . . . . . 137
Translatory Motion of the Solar System . . . . . . . . . . . . . . 145
The Milky Way . . . . . . . . . . . . . . . . . . . . . . . . . . .150
Starless Openings . . . . . . . . . . . . . . . . . . . . . . . 152
Terrestrial Phenomena . . . . . . . . . . . . . . . . . . . . . . .154
Geographical Distribution . . . . . . . . . . . . . . . . . . . . .161
Figure of the Earth . . . . . . . . . . . . . . . . . . . . . . . .163
Density of the Earth . . . . . . . . . . . . . . . . . . . . . . . 169
Internal Heat of the Earth . . . . . . . . . . . . . . . . . . . . 172
Mean Temperature of the Earth . . . . . . . . . . . . . . . . . . .175
Terrestrial Magnetism . . . . . . . . . . . . . . . . . . . . . . 177
Magnetism . . . . . . . . . . . . . . . . . . . . . . . . . . . . .183
Aurora Borealis . . . . . . . . . . . . . . . . . . . .. . . . . .193
Geognostic Phenomena . . . . . . . . . . . . . . . . . . . . . . . 202
Earthquakes . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
Gaseous Emanations . . . . . . . . . . . . . . . . . . . . . . . . 207
Hot Springs . . . . . . . . . . . . . . . . . . . . . . . . . . . .221
Salses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .224
Volcanoes . . . . . . . . . . . . . . . . . . . . . . . . . . . . .227
Rocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .247
Palaeontology . . . . . . . . . . . . . . . . . . . . . . . . . . .270
Geognostic Periods . . . . . . . . . . . . . . . . . . . . . . . . 286
Physical Geography . . . . . . . . . . . . . . . . . . . . . . . . 287
Meteorology . . . . . . . . . . . . . . . . . . . . . . . . . . . .311
Atmospheric Pressure . . . . . . . . . . . . . . . . . . . . . . . 315
Climatology . . . . . . . . . . . . . . . . . . . . . . . . . . . .317
The Snow-line . . . . . . . . . . . . . . . . . . . . . . . . . . .329
Hygrometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . 332
Atmospheric Electricity . . . . . . . . . . . . . . . . . . . . . .335
Organic Life . . . . . . . . . . . . . . . . . . . . . . . . . . . 339
Motion in Plants . . . . . . . . . . . . . . . . . . . . . . . . . 341
Universality of Animal Life . . . . . . . . . . . . . . . . . . . .342
Geography of Plants and Animals . . . . . . . . . . . . . . . . . .346
Floras of different Countries . . . . . . . . . . . . . . . . . . .350
Man . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .352
Races . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .353
Language . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 357
Conclusion of the Subject . . . . . . . . . . . . . . . . . . . . .359
p 15
SUMMARY.
-----------
Translator's Preface.
Author's Preface.
Vol I.
GENERAL SUMMARY OF THE CONTENTS.
Introduction. -- Reflections on the different Degrees of Enjoyment presented
to us by the Aspect of Nature and the scientific Exposition of the Laws of
the Universe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . .Page 23-78
Insight into the connection of phenomena as the aim of all natural
investigation. Nature presents itself to meditative contemplation as a
unity in diversity. Differences in the grades of enjoyment yielded by
nature. Effect of contact with free nature; enjoyment derived from nature
independently of a knowledge of the action of natural forces, or of the
physiognomy and configuration of the surface, or of the character of
vegetation. Reminiscences of the woody valleys of the Cordilleras and of
the Peak of Teneriffe. Advantages of the mountainous region near the
equator, where the multiplicity of natural impressions attains its maximum
within the most circumscribed limits, and where it is permitted to man
simultaneously to behold all the stars of the firmament and all the forms of
vegetation -- p. 23-33.
Tendency toward the investigation of the causes of physical phenomena.
Erroneous views of the character of natural forces arising from an imperfect
mode of observation or of induction. The crude accumulation of physical
dogmas transmitted from one country to another. Their diffusion among the
higher classes.
Scientific physics are associated with another and a deep-rooted system of
untried and misunderstood experimental positions. Investigation of natural
laws. Apprehension that nature may lose a portion of its secret charm by an
inquiry into the internal character of its forces, and that the enjoyment of
nature must necessarily be weakened by a study of its domain. Advantages of
general views which impart an exalted and solemn character to natural
science. The possibility of separating generalities from specialties.
Examples drawn from astronomy, recent optical discoveries, physical
geognosy, and the geography of plants. Practicability of the study of
physical cosmography -- p. 33-54. Misunderstood popular knowledge,
confounding cosmography with a mere encyclopedic enumeration of natural
sciences. Necessity for a simultaneous regard for all branches of natural
science. Influence of this study on national prosperity and the welfare of
nations; its more earnest and characteristic aim is an inner one, arising
from exalted mental activity. Mode of treatment with regard to the object
and presentation; reciprocal connection existing between thought and speech
-- p. 54-56.
The notes to p. 28-33. Comparative hypsometrical data of the elevations of
the Dhawalagiri, Jawahir, Chimborazo, Aetna (according to the measurement of
Sir John Herschel), the Swiss Alps, etc. -- p. 28. Rarity
p 16
of palms and ferns in the Himalaya Mountains -- p. 29. European vegetable
forms in the Indian Mountains -- p. 30. Northern and southern limits of
perpetual snow on the Himalaya; influence of the elevated plateau of Thibet
-- p. 30-33. Fishes of an earlier world -- p. 46.
Limits and Method of Exposition of the Physical Description of the Universe
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . .
Page 56-78
Subjects embraced by the study of the Cosmos or of physical cosmography.
Separation of other kindred studies -- p. 56-62. The uranological portion
of the Cosmos is more simple than the telluric; the impossibility of
ascertaining the diversity of matter simplifies the study of the mechanism
of the heavens. Origin of the word 'Cosmos', its signification of adornment
and order of the universe. The 'existing' can not be absolutely separated
in our contemplation of nature from the 'future'. History of the world and
description of the world -- p. 26-73.
Attempts to embrace the multiplicity of the phenomena of the Cosmos in the
unity of thought and under the form of a purely rational combination.
Natural philosophy, which preceded all exact observation in antiquity, is a
natural, but not unfrequently ill-directed, effort of reason. Two forms of
abstraction rule in the whole mass of knowledge, viz.: the 'quantitative',
relative determinations according to number and magnitude, and
'qualitative', material characters. Means of submitting phenomena to
calculation. Atoms, mechanical methods of construction. Figurative
representations; mythical conception of imponderable matters, and the
peculiar vital forces in every organism. That which is attained by
observation and experiment (calling forth phenomena) leads, by analogy and
induction, to a knowledge of 'empirical laws'; their gradual simplification
and generalization. Arrangement of the facts discovered in accordance with
leading ideas. The treasure of empirical contemplation, collected through
ages, is in no danger of experiencing any hostile agency from philosophy --
p. 73-78.
[In the notes appended to p. 66-70 are considerations of the general and
comparative geography of Varenius. Philological investigation into the
meaning of the words [Greek word] and 'mundus'.]
Delineation of Nature. General Review of Natural Phenomena. . . . . p.
79-359
Introduction -- p. 79-83. A descriptive delineation of the world embraces
the whole universe ([Greek words]) in the celestial and terrestrial spheres.
Form and course of the representation. It begins with the laws of
gravitation, and with the region of the remotest nebulous spots and double
stars, and then, gradually descending through the starry stratum to which
our solar system belongs, it contemplates this terrestrial spheroid,
surrounded by air and water, and finally, proceeds to the consideration of
the form of our planet, its temperature and magnetic tension, and the
fullness of organic vitality which is unfolded on its surface under the
action of light. Partial insight into the relative dependence existing
among all phenomena. Amid all the mobile and unstable elements in space,
'mean numerical values' are the ultimate aim of investigation, being the
expression of the physical laws, or forces of the Cosmos. The delineation
of the universe does not begin with the earth, from which a merely
subjective point of view might have led us to start, but rather with the
objects comprised in the regions of space. Distribution of matter, which is
partially conglomerated into rotating
p 17
and circling heavenly bodies of very different density and magnitude, and
partly scattered as self-luminous vapor. Review of the separate portions of
the picture of nature, for the purpose of explaining the reciprocal
connection of all phenomena.
I. Celestial Portion of the Cosmos . . . . . . . . . . . . . . . . .Page
83-154
II. Terrestrial Portion of the Cosmos . . . . . . . . . . . . . . . .p.
154-359
a. Form of the earth, its mean density, quantity of heat, electro-magnetic
activity, process of light -- p. 154-202.
b. Vital activity of the earth toward its external surface. Reaction of
the interior of a planet on its crust and surface. Subterranean noise
without waves of concussion. Earthquakes dynamic phenomena -- p. 202-217.
c. Material products which frequently accompany earthquakes. Gaseous and
aqueous springs. Salses and mud volcanoes. Upheavals of the soil by
elastic forces -- p. 217-228.
d. Fire-emitting mountains. Craters of elevation. Distribution of
volcanoes on the earth -- p. 228-247.
e. Volcanic forces form new kinds of rock, and metamorphose those already
existing. Geognostical classification of rocks into four groups. Phenomena
of contact. Fossiliferous strata; their vertical arrangement. The faunas
and floras of an earlier world. Distribution of masses of rock -- p.
247-384.
f. Geognostical epochs, which are indicated by the mineralogical difference
of rocks, have determined the distribution of solids and fluids into
continents and seas. Individual configuration of solids into horizontal
expansion and vertical elevation. Relations of area. Articulation.
Probability of the continued elevation of the earth's crust in ridges -- p.
284-301.
g. Liquid and aeriform envelopes of the solid surface of our planet.
Distribution of heat in both. The sea. The tides. Currents and their
effects -- p. 301-311.
h. The atmosphere. Its chemical composition. Fluctuations in its density.
Law of the direction of the winds. Mean temperature. Enumeration of the
causes which tend to raise and lower the temperature. Continental and
insular climates. East and west coasts. Cause of the curvature of the
isothermal lines. Limits of perpetual snow. Quantity of vapor.
Electricity in the atmosphere. Forms of the clouds -- p. 311-339.
i. Separation of inorganic terrestrial life from the geography of vital
organisms; the geography of vegetables and animals. Physical gradations of
the human race -- p. 339-359.
Special Analysis of the Delineation of Nature, including References to the
Subjects treated of in the Notes.
I. Celestial Portion of the Cosmos . . . . . . . . . . . . . . . . . p.
83-154
The universe and all that it comprises -- multiform nebulous spots,
planetary vapor, and nebulous stars. The picturesque charm of a southern
sky -- note, p. 85. Conjectures on the position in space of the world. Our
stellar masses. A cosmical island. Gauging stars. Double stars revolving
round a common center. Distance of the star 61 Cygni -- p. 88 and note.
Our solar system more complicated than was conjectured at the close of the
last century. Primary planets with Neptune, Astrea, Hebe, Iris, and Flora,
now constitute 16; secondary planets 18; myriad of comets of which many of
the inner ones are inclosed
p 18
in the orbits of the planets; a rotating ring (the zodiacal light) and
meteoric stones, probably to be regarded as small cosmical bodies. The
telescopic planets, Vesta, Juno, Ceres, Pallas, Astrea, Hebe, Iris and
Flora, with their frequently intersecting, strongly inclined, and more
eccentric orbits, constitute a central group of separation between the inner
planetary group (Mercury, Venus, the Earth, and Mars) and the outer group
(Jupiter, Saturn, Uranus, and Neptune). Contrasts of these planetary
groups. Relations of distance from one central body. Differences of
absolute magnitude, density, period of revolution, eccentricity, and
inclination of the orbits. The so-called law of the distances of the
planets from their central sun. The planets which have the largest number
of moons -- p. 96 and note. Relations in space, both absolute and relative,
of the secondary planets. Largest and smallest of the moons. Greatest
approximation to a primary planet. Retrogressive movement of the moons of
Uranus. Libration of the Earth's satellite -- p. 98 and note. Comets; the
nucleus and tail; various forms and directions of the emanations in conoidal
envelopes, with more or less dense walls. Several tails inclined toward the
sun; change of form of fixed stars by the nuclei of comets. Eccentricity of
their orbits and periods of revolution. Greatest distance and greatest
approximation of comets. Passage through the system of Jupiter's
satellites. Comets of short periods of revolution, more correctly termed
inner comets (Encke, Biela, Faye) -- p. 107 and note. Revolving aerolites
(meteoric stones, fire-balls, falling stars). Their planetary velocity,
magnitude, form, observed height. Periodic return in streams; the November
stream and the stream of St. Lawrence. Chemical composition of meteoric
asteroids -- p. 130 and notes. Ring of zodiacal light. Limitation of the
present solar atmosphere -- p. 141 and note. Translatory motion of the
whole solar system -- p. 145-149 and note. The existence of the law of
gravitation beyond our solar system. The milky way of stars and its
conjectured breaking up. Milky way of nebulous spots, at right angles with
that of the stars. Periods of revolutions of bi-colored double stars.
Canopy of stars; openings in the stellar stratum. Events in the universe;
the apparition of new stars. Propagation of light, the aspect of the starry
vault of the heavens conveys to the mind an idea of inequality of time -- p.
149-154 and notes.
II. Terrestrial Portion of the Cosmos . . . . . . . . . . . . . . Page
154-359
a. Figure of the earth. Density, quantity of heat, electro-magnetic
tension, and terrestrial light -- p. 154-202 and note. Knowledge of the
compression and curvature of the earth's surface acquired by measurements of
degrees, pendulum oscillations, and certain inequalities in the moon's
orbit. Mean density of the earth. The earth's crust, and the depth to
which we are able to penetrate -- p. 159, 160, note. Threefold movement of
the heat of the earth; its thermic condition. Law of the increase of heat
with the increase of depth -- p. 160, 161 and note. Magnetism electricity
in motion. Periodical variation of terrestrial magnetism. Disturbance of
the regular course of the magnetic needle. Magnetic storms; extension of
their action. Manifestations of magnetic force on the earth's surface
presented under three classes of phenomena, namely, lines of equal force
(isodynamic), equal inclination (isoclinic), and equal deviation (isogonic).
Position of the magnetic pole. Its probable connection with the poles of
cold. Change of all the magnetic phenomena of the earth. Erection of
magnetic observatories
p 19
since 1828; a far-extending net-work of magnetic stations -- p. 190 and
note. Development of light at the magnetic poles; terrestrial light as a
consequence of the electro-magnetic activity of our planet. Elevation of
polar light. Whether magnetic storms are accompanied by noise. Connection
of polar light (an electro-magnetic development of light) with the formation
of cirrus clouds. Other examples of the generation of terrestrial light --
p. 202 and note.
b. The vital activity of a planet manifested from within outward, the
principal source of geognostic phenomena. Connection between merely dynamic
concussions or the upheaval of whole portions of the earth's crust,
accompanied by the effusion of matter, and the generation of gaseous and
liquid fluids, of hot mud and fused earths, which solidify into rocks.
Volcanic action, in the most general conception of the idea, is the reaction
of the interior of a planet on its outer surface. Earthquakes. Extent of
the circles of commotion and their gradual increase. Whether there exists
any connection between the changes in terrestrial magnetism and the
processes of the atmosphere. Noises, subterranean thunder without any
perceptible concussion. The rocks which modify the propagation of the waves
of concussion. Upheavals; eruption of water, hot steam, mud mofettes,
smoke, and flame during an earthquake -- p. 202-218 and notes.
c. Closer consideration of material products as a consequence of internal
planetary activity. There rise from the depths of the earth, through
fissures and cones of eruption, various gases, liquid fluids (pure or
acidulated), mud, and molten earths. Volcanoes are a species of
intermittent spring. Temperature of thermal springs; their constancy and
change. Depth of the foci -- p. 219-224 and notes. Salses, mud volcanoes.
While fire-emitting mountains, being sources of molten earths, produce
volcanic rocks, spring water forms, by precipitation, strata of limestone.
Continued generation of sedimentary rocks -- p. 228 and note.
d. Diversity of volcanic elevations. Dome-like closed trachytic mountains.
Actual volcanoes which are formed from craters of elevations or among the
detritus of their original structure. Permanent connection of the interior
of our earth with the atmosphere. Relation to certain rocks. Influence of
the relations of height on the frequency of the eruptions. Heights of the
cone of cinders. Characteristics of those volcanoes which rise above the
snow-line. Columns of ashes and fire. Volcanic storm during the eruption.
Mineral composition of lavas -- p. 236 and notes. Distribution of volcanoes
on the earth's surface; central and linear volcanoes; insular and littoral
volcanoes. Distance of volcanoes from the sea-coast. Extinction of
volcanic forces -- p. 246 and notes.
e. Relation of volcanoes to the character of rocks. Volcanic forces form
new rocks, and metamorphose the more ancient ones. The study of these
relations leads, by a double course, to the mineral portion of geognosy (the
study of the textures and of the position of the earth's strata), and to the
configuration of continents and insular groups elevated above the level of
the sea (the study of the geographical form and outlines of the different
parts of the earth. Classification of rocks according to the scale of the
phenomena of structure and metamorphosis, which are still passing before our
eyes. Rocks of eruption, sedimentary rocks, changed (metamorphosed) rocks,
conglomerates -- compound rocks are definite associations of
cryctognostically simple fossils. There are four phases in the formative
condition; rocks of eruption,
p 20
endogenous (granite, sienite, porphyry, greenstone, hyperathene, rock,
euphotide, melaphyre, basalt, and phonolithe); sedimentary rocks (silurian
schist, coal measures, limestone, travertino, infusorial deposit);
metamorphosed rock, which contains also, together with the detritus mica
schist, and more ancient metamorphic masses. Aggregate and sandstone
formations. The phenomenon of contact explained by the artificial imitation
of minerals. Effects of pressure and the various rapidity of cooling.
Origin of granular or saccharoidal marble, silicification of schist into
ribbon jasper. Metamorphosis of calcareous marl into micaceous schist
through granite. Conversion of dolomite and granite into argillaceous
schist, by contact with basaltic and doleritic rocks. Filling up of the
veins from below. Processes of cementation in agglomerate structures.
Friction conglomerates -- p. 269 and note. Relative age of rocks,
chronometry of the earth's crust. Fossiliferous strata. Relative age of
organisms. Simplicity of the first vital forms. Dependence of
physiological gradations on the age of the formations. Geognostic horizon,
whose careful investigation may yield certain data regarding the identity or
the relative age of formations, the periodic recurrence of certain strata,
their parallelism, or their total suppression. Types of the sedimentary
structures considered in their most simple and general characters; silurian
and devonian formations (formerly known as rocks of transition); the lower
trias (mountain limestone, coal measures, together with 'todilegende' and
zechstein); the upper trias (butter sandstone, muschelkalk, and keuper);
Jura limestone (lias and oolite); freestone, lower and upper chalk, as the
last of the flotz strata, which begin with mountain limestone; tertiary
formations in three divisions, which are designated by granular limestone,
lignite, and south Apennine gravel -- p. 269-278.
The faunas and floras of an earlier world, and their relations to existing
organisms. Colossal bones of antediluvian mammalia in the upper alluvium.
Vegetation of an earlier world; monuments of the history of its vegetation.
The points at which certain vegetable groups attain their maximum; cycadeae
in the keuper and lias, and coniferae in the butter sandstone. Lignite and
coal measures (amber-tree). Deposition of large masses of rock; doubts
regarding their origin -- p. 285 and note.
f. The knowledge of geognostic epochs -- of the upheaval of mountain chains
and elevated plateaux, by which lands are both formed and destroyed, leads,
by an internal causal connection, to the distribution into solids and
fluids, and to the peculiarities in the natural configuration of the earth's
surface. Existing areal relations of the solid to the fluid differ
considerably from those presented by the maps of the physical portion of a
more ancient geography. Importance of the eruption of quartzose, porphyry
with reference to the then existing configuration of continental masses.
Individual conformation in horizontal extension (relations of articulation)
and in vertical elevation (hypsometrical views). Influence of the relations
of the area of land and sea on the temperature, direction of the winds,
abundance or scarcity of organic products, and on all meteorological
processes collectively. Direction of the major axes of continental masses.
Articulation and pyramidal termination toward the south. Series of
peninsulas. Valley-like formation of the Atlantic Ocean. Forms which
frequently recur -- p. 285-293 and notes. Ramifications and systems of
mountain chains, and the means of determining their relative ages. Attempts
to determine the centre of gravity of the volume of the lands upheaved above
the level
p 21
of the sea. The elevation of continents is still progressing slowly, and is
being compensated for at some definite points by a perceptible sinking. All
geognostic phenomena indicate a periodical alteration of activity in the
interior of our planet. Probability of new elevations of ridges -- p.
293-301 and notes.
g. The solid surface of the earth has two envelopes, one liquid, and the
other aeriform. Contrasts and analogies which these envelopes -- the sea
and the atmosphere -- present in their conditions of aggregation and
electricity, and in their relations of currents and temperature. Depths of
the ocean and of the atmosphere, the shoals of which constitute our
highlands and mountain chains. The degree of heat at the surface of the sea
in different latitudes and in the lower strata. Tendency of the sea to
maintain the temperature of the surface in the strata nearest to the
atmosphere, in consequence of the mobility of its particles and the
alteration in its density. Maximum of the density of salt water. Position
of the zones of the hottest water, and of those having the greatest saline
contents. Thermic influence of the lower polar current and the counter
currents in the straits of the sea -- p. 302-304 and notes. General level
of the sea, and permanent local disturbances of equilibrium; the periodic
disturbances manifested as tides. Oceanic currents; the equatorial or
rotation current, the Atlantic warm Gulf Stream, and the further impulse
which it receives; the cold Peruvian stream in the eastern portion of the
Pacific Ocean of the southern zone. Temperature of shoals. The universal
diffusion of life in the ocean. Influence of the small submarine sylvan
region at the bottom of beds of rooted algae, or on far-extending floating
layers of fucus -- p. 302-311 and notes.
h. The gaseous envelope of our planet, the atmosphere. Chemical
composition of the atmosphere, its transparency, its polarization, pressure,
temperature, humidity, and electric tension. Relation of oxygen to
nitrogen; amount of carbonic acid; carbureted hydrogen; ammoniacal vapors.
Miamata. Regular (horary) changes in the pressure of the atmosphere. Mean
barometrical height at the level of the sea in different zones of the earth.
Isobarometrical curves. Barometrical windroses. Law of rotation of the
winds, and its importance with reference to the knowledge of many
meteorological processes. Land and sea winds, trade winds and monsoons --
p. 311-317. Climatic distribution of heat in the atmosphere, as the effect
of the relative position of transparent and opaque masses (fluid and solid
superficial area), and of the hypsometrical configuration of continents.
Curvature of the isothermal lines in a horizontal and vertical direction, on
the earth's surface and in the superimposed strata of air. Convexity and
concavity of the isothermal lines. Mean heat of the year, seasons, months,
and days. Enumeration of the causes which produce disturbances in the form
of isothermal lines, i.e., their deviation from the position of the
geographical parallels. Isochimenal and isotheral lines are the lines of
equal winter and summer heat. Causes which raise or lower the temperature.
Radiation of the earth's surface, according to its inclination, color,
density, dryness, and chemical composition. The form of the cloud which
announces what is passing in the upper strata of the atmosphere is the image
of the strongly radiating ground projected on a hot summer sky. Contrast
between an insular or littoral climate, such as is experienced by all
deeply-articulated continents, and the climate of the interior of large
tracts of land. East and west coasts. Difference between the southern and
northern hemispheres. Thermal scales of
p 22
cultivated plants, going down from the vanilla, cacoa, and musaceae, by
citrous and olives, and to vines yielding potable wines. The influence
which these scales exercise on the geographical distribution of cultivated
plants. The favorable ripening and the immaturity of fruits are essentially
influenced by the difference in the action of direct or scattered light in a
clear sky or in one overcast with mist. General summary of the causes which
yield a more genial climate to the greater portion of Europe considered as
the western peninsula of Asia -- p. 326. Determination of the changes in
the mean annual and summer temperature, which correspond to one degree of
geographical latitude. Equality of the mean temperature of a mountain
station, and of the polar distance of any point lying at the level of the
sea. Decrease of temperature with the decrease in elevation. Limits of
perpetual snow, and the fluctuations in these limits. Causes of disturbance
in the regularity of the phenomenon. Northern and southern chains of the
Himalaya; habitability of the elevated plateaux of Thibet -- p. 331.
Quantity of moisture in the atmosphere, according to the hours of the day,
the seasons of the year, degrees of latitude, and elevation. Greatest
dryness of the atmosphere observed in Northern Asia, between the river
districts of the Irtysch and the Obi. Dew, a consequence of radiation.
Quantity of rain -- p. 335. Electricity of the atmosphere, and disturbance
of the electric tension. Geographical distribution of storms.
Predettermination of atmospheric changes. The most important climatic
disturbances can not be traced, at the place of observation, to any local
cause, but are rather the consequence of some occurrence by which the
equilibrium in the atmospheric currents has been destroyed at some
considerable distance -- p. 335-339.
i. Physical geography is not limited to elementary inorganic terrestrial
life, but, elevated to a higher point of view, it embraces the sphere of
organic life, and the numerous gradations of its typical development.
Animal and vegetable life. General diffusion of life in the sea and on the
land; microscopic vital forms discovered in the polar ice no less than in
the depths of the ocean within the tropics. Extension imparted to the
horizon of life by Ehrenberg's discoveries. Estimation of the mass (volume)
of animal and vegetable organisms -- p. 339-346. Geography of plants and
animals. Migrations of organisms in the ovum, or by means of organs capable
of spontaneous motion. Spheres of distribution depending on climatic
relations. Regions of vegetation, and classification of the genera of
animals. Isolated and social living plants and animals. The character of
flora and fauna is not determined so much by the predominance of separate
families, in certain parallels of latitude, as by the highly complicated
relations of the association of many families, and the relative numerical
value of their species. The forms of natural families which increase or
decrease from the equator to the poles. Investigations into the numerical
relation existing in different districts of the earth between each one of
the large families to the whole mass of phanerogamia -- p. 346-351. The
human race considered according to its physical gradations, and the
geographical distribution of its simultaneously occurring types. Races and
varieties. All races of men are forms of one single species. Unity of the
human race. Languages considered as the intellectual creations of mankind,
or as portions of the history of mental activity, manifest a character of
nationality, although certain historical occurrences have been the means of
diffusing idioms of the same family of languages among nations of wholly
different descent -- p. 351-359.
In This material taken from pages 23 to 56
COSMOS: A Sketch of the Physical Description of the Universe, Vol. 1
by Alexander von Humboldt
Translated by E C Otte
from the 1858 Harper & Brothers edition of Cosmos, volume 1
--------------------------------------------------
p 23
INTRODUCTION.
----------------
REFLECTIONS ON THE DIFFERENT DEGREES OF ENJOYMENT PRESENTED TO US BY THE
ASPECT OF NATURE AND THE STUDY OF HER LAWS.
In attempting, after a long absence from my native country, to develop the
physical phenomena of the globe, and the simultaneous action of the forces
that pervade the regions of space, I experience a two-fold cause of anxiety.
The subject before me is so inexhaustible and so varied, that I fear either
to fall into the superficiality of the encyclopedist, or to weary the mind
of my reader by aphorisms consisting of mere generalities clothed in dry and
dogmatical forms. Undue conciseness often checks the flow of expression,
while diffuseness is alike detrimental to a clear and precise exposition of
our ideas. Nature is a free domain, and the profound conceptions and
enjoyments she awakens within us can only be vividly delineated by thought
clothed in exalted forms of speech, worthy of bearing witness to the majesty
and greatness of the creation.
In considering the study of physical phenomena, not merely in its bearings
on the material wants of life, but in its general influence on the
intellectual advancement of mankind, we find its noblest and most important
result to be a knowledge of the chain of connection, by which all natural
forces are linked together, and made mutually dependent upon each other; and
it is the perception of these relations that exalts our views and ennobles
our enjoyments. Such a result can, however, only be reaped as the fruit of
observation and intellect, combined with the spirit of the age, in which are
reflected all the varied phases of thought. He who can trace, through
by-gone times, the stream of our knowledge to its primitive source, will
learn from history how, for thousands of years, man has labored, amid the
ever-recurring changes of form, to recognize the invariability of natural
laws, and has thus, by the force of mind, gradually subdued a great portion
of the physical world to his dominion. In interrogating the history of the
past, we trace the mysterious course of ideas yielding the first glimmering
perception of the same image of
p 24
a Cosmos, or harmoniously ordered whole, which, dimly shadowed forth to the
human mind in the primitive ages of the world, is now fully revealed to the
maturer intellect of mankind as the result of long and laborious observation.
Each of these epochs of the contemplation of the external world -- the
earliest dawn of thought and the advanced stage of civilization -- has its
own source of enjoyment. In the former, this enjoyment, in accordance with
the simplicity of the primitive ages, flowed from an intuitive feeling of
the order that was proclaimed by the invariable and successive reappearance
of the heavenly bodies, and by the progressive development of organized
beings; while in the latter, this sense of enjoyment springs from a definite
knowledge of the phenomena of nature. When man began to interrogate nature,
and, not content with observing, learned to evoke phenomena under definite
conditions; when once he sought to collect and record facts, in order that
the fruit of his labors might aid investigation after his own brief
existence had passed away, the 'philosophy of Nature' cast aside the vague
and poetic garb in which she had been enveloped from her origin, and, having
assumed a severer aspect, she now weighs the value of observations, and
substitutes induction and reasoning for conjecture and assumption. The
dogmas of former ages survive now only in the superstitions of the people
and the prejudices of the ignorant, or are perpetuated in a few systems,
which, conscious of their weakness, shroud themselves in a vail of mystery.
We may also trace the same primitive intuitions in languages exuberant in
figurative expressions; and a few of the best chosen symbols engendered by
the happy inspiration of the earliest ages, having by degrees lost their
vagueness through a better mode of interpretation, are still preserved among
our scientific terms.
Nature considered 'rationally', that is to say, submitted to the process of
thought, is a unity in diversity of phenomena; a harmony blending together
all created things, however dissimilar in form and attributes; one great
whole ([Greek words]) animated by the breath of life. The most important
result of a rational inquiry into nature is, therefore, to establish the
unity and harmony of this stupendous mass of force and matter, to determine
with impartial justice what is due to the discoveries of the past and to
those of the present, and to analyze the individual parts of natural
phenomena without succumbing beneath the weight of the whole. Thus, and
thus alone, is it permitted to man, while mindful of the high destiny
p 25
of his race, to comprehend nature, to lift the vail that shrouds her
phenomena, and as it were, submit the results of observation to the test of
reason and of intellect.
In reflecting upon the different degrees of enjoyment presented to us in the
contemplation of nature, we find that the first place must be assigned to a
sensation, which is wholly independent of an intimate acquaintance with the
physical phenomena presented to our view, or of the peculiar character of
the region surrounding us. In the uniform plain bounded only by a distant
horizon, where the lowly heather, the cistus, or waving grasses, deck the
soil; on the ocean shore, where the waves, softly rippling over the beach,
leave a track, green with the weeds of the sea; every where, the mind is
penetrated by the same sense of the grandeur and vast expanse of nature,
revealing to the soul, by a mysterious inspiration, the existence of laws
that regulate the forces of the universe. Mere communion with nature, mere
contact with the free air, exercise a soothing yet strengthening influence
on the wearied spirit, calm the storm of passion, and soften the heart when
shaken by sorrow to its inmost depths. Every where, in every region of the
globe, in every stage of intellectual culture, the same sources of enjoyment
are alike vouchsafed to man. The earnest and solemn thoughts awakened by a
communion with nature intuitively arise from a presentiment of the order and
harmony pervading the whole universe, and from the contrast we draw between
the narrow limits of our own existence and the image of infinity revealed on
every side, whether we look upward to the starry vault of heaven, scan the
far-stretching plain before us, or seek to trace the dim horizon across the
vast expanse of ocean.
The contemplation of the individual characteristics of the landscape, and of
the conformation of the land in any definite region of the earth, gives rise
to a different source of enjoyment, awakening impressions that are more
vivid, better defined, and more congenial to certain phases of the mind,
than those of which we have already spoken. At one time the heart is
stirred by a sense of the grandeur of the face of nature, by the strife of
the elements, or, as in Northern Asia by the aspect of the dreary barrenness
of the far-stretching steppes; at another time, softer emotions are excited
by the contemplation of rich harvests wrested by the hand of man from the
wild fertility of nature, or by the sight of human habitations raised beside
some wild and foaming torrent. Here I regard less the degree of intensity
than the difference existing in the
p 26
various sensations that derive their charm and permanence from the peculiar
character of the scene.
If I might be allowed to abandon myself to the recollections of my own
distant travels, I would instance, among the most striking scenes of nature,
the calm sublimity of a tropical night, when the stars, not sparkling, as in
our northern skies, shed their soft and planetary light over the
gently-heaving ocean; or I would recall the deep valleys of the Cordilleras,
where the tall and slender palms pierce the leafy vail around them, and
waving on high their feathery and arrow-like branches for, as it were, "a
forest above a forest;"* or I would describe the summit of the Peak of
Teneriffe, when a horizontal layer of clouds, dazzling in whiteness, has
separated the cone of cinders from the plain below, and suddenly the
ascending current pierces the cloudy vail, so that the eye of the traveler
may range from the brink of the crater, along the vine-clad slopes of
Orotava, to the orange gardens and banana groves that skirt the shore. In
scenes like these, it is not the peaceful charm uniformly spread over the
face of nature that moves the heart, but rather the peculiar physiognomy and
conformation of the land, the features of the landscape, the ever varying
outline of the clouds, and their blending with the horizon of the sea,
whether it lies spread before us like a smooth and shining mirror, or is
dimly seen through the morning mist. All that the senses can but
imperfectly comprehend, all that is most awful in such romantic scenes of
nature, may become a source of enjoyment to man, by opening a wide field to
the creative powers of his imagination. Impressions change with the varying
movements of the mind, and we are led by a happy illusion to believe that we
receive from the external world that with which we have ourselves invested
it.
[footnote] *This expression is taken from a beautiful description of
tropical forest scenery in 'Paul and Virginia', by Bernardia de Saint Pierre.
When far from our native country, after a long voyage, we tread for the
first time the soil of a tropical land, we experience a certain feeling of
surprise and gratification in recognizing, in the rocks that surround us,
the same inclined schistose strata, and the same columnar basalt covered
with cellular amygdaloids, that we had left in Europe, and whose identity of
character, in latitudes so widely different, reminds us that the
solidification of the earth's crust is altogether independent of climatic
influences. But these rocky masses of schist and of basalt are covered with
vegetation of a character with which we are unacquainted, and of a
physiognomy wholly
p 27
unknown to us; and it is then, amid the colossal and majestic forms of an
exotic flora, that we feel how wonderfully the flexibility of our nature
fits us to receive new impressions, linked together by a certain secret
analogy. We so readily perceive the affinity existing among all the forms
of organic life, that although the sight of a vegetation similar to that of
our native country might at first be most welcome to the eye, as the sweet
familiar sounds of our mother tongue are to the ear, we nevertheless, by
degrees, and almost imperceptibly, become familiarized with a new home and a
new climate. As a true citizen of the world, man every where habituates
himself to that which surrounds him; yet fearful, as it were, of breaking
the links of association that bind him to the home of his childhood, the
colonist applies to some few plants in a far-distant clime the names he had
been familiar with in his native land; and by the mysterious relations
existing among all types of organization, the forms of exotic vegetation
present themselves to his mind as nobler and more perfect developments of
those he had loved in earlier days. Thus do the spontaneous impressions of
the untutored mind lead, like the laborious deductions of cultivated
intellect, to the same intimate persuasion, that one sole and indissoluble
chain binds together all nature.
It may seem a rash attempt to endeavor to separate, into its different
elements, the magic power exercised upon our minds by the physical world,
since the character of the landscape, and of every imposing scene in nature,
depends so materially upon the mutual relation of the ideas and sentiments
simultaneously excited in the mind of the observer.
The powerful effect exercised by nature springs, as it were, from the
connection and unity of the impressions and emotions produced; and we can
only trace their different sources by analyzing the individuality of objects
and the diversity of forces.
The richest and most varied elements for pursuing an analysis of this nature
present themselves to the eyes of the traveler in the scenery of Southern
Asia, in the Great Indian Archipelago, and more especially, too, in the New
Continent, where the summits of the lofty Cordilleras penetrate the confines
of the aerial ocean surrounding our globe, and where the same subterranean
forces that once raised these mountain chains still shake them to their
foundation and threaten their downfall.
Graphic delineations of nature, arranged according to systematic views, are
not only suited to please the imagination,
p 28
but may also, when properly considered, indicate the grades of the
impressions of which I have spoken, from the uniformity of the sea-shore, or
the barren steppes of Siberia, to the inexhaustible fertility of the torrid
zone. If we were even to picture to ourselves Mount Pilatus placed on the
Schreckhorn,* or the Schneekoppe of Silesia on Mont Blanc, we should
p 29
not have attained to the height of that great Colossus of the Andes, the
Chimborazo, whose height is twice that of Mont Aetna; and we must pile the
Righi, or Mount Athos, on the summit of the Chimborazo, in order to form a
just estimate of the elevation of the Dhawalagiri, the highest point of the
Himalaya.
[footnote] *These comparisons are only approximative. The several
elevations above the level of the sea are, in accurate numbers, as follows:
The Schneekoppe or Riesenkoppe, in Silesia about 5270 feet, according to
Hallaschka. The Righi, 5902 feet, taking the height of the Lake of Lucerne
at 1426 feet, according to Eschman. (See 'Compte Rendu des Mesures
Trigonometriques en Suisse', 1840, p. 230.) Mount Athos, 6775 feet,
according to Captain Gaultier; Mount Pilatus, 7546 feet; Mount Aetna, 10,871
feet, according to Captain Smyth; or 10,874 feet, according to the
barometrical measurement made by Sir John Herschel, and communicated to me
in writing in 1825, and 10,899 feet, according to angles of altitude taken
by Cacciatore at Palermo (calculated by assuming the terrestrial refraction
to be 0.076); the Schreckhorn, 12,383 feet; the Jungfrau, 13,720 feet,
according to Tralles; Mount Blanc, 15,775 feet, according to the different
measurements considered by Roger ('Bibl. Univ.', May, 1828, 0. 24-53),
15,733 feet, according to the measurements taken from Mount Columbier by
Carlini in 1821, and 15,748 feet, as measured by the Austrian engineers from
Trelod and the Glacier d'Ambin.
[footnote continued]
The actual height of the Swiss mountains fluctuates, according to Eschman's
observations, as much as 25 English feet, owing to the varying thickness of
the stratum of snow that covers the summits. Chimborazo is, according to my
trigonometrical measurements, 21,421 feet (see Humboldt, 'Recueil d'Obs.
Astr.', tome i., p. 73), and Dhawalagiri, 28,074 feet. As there is a
difference of 445 feet between the determinations of Blake and Webb, the
elevation assigned to the Dhawalagiri (or white mountain, from the Sanscrit
'dhawala', white, and 'giri', mountain) can not be received with the same
confidence as that of the Jawahir, 25,749 feet, since the latter rests on a
complete trigonomietrical measurement (see Herbert and Hodgson in the
'Asiat. Res.', vol. xiv., p. 189, and Suppl. to 'Encycl. Brit.', vol. iv.,
p. 643). I have shown elsewhere ('Ann. des Sciences Naturelles', Mars,
1825) that the height of the Dhawalagiri (28,074 feet) depends on several
elements that have not been ascertained with certainty, as azimuths and
latitudes (Humboldt, 'Asie Centrale', t. iii., p. 282). It has been
believed, but without foundation, that in the Tartaric chain, north of
Thibet, opposite to the chain of Kuen-lun, there are several snowy summits,
whose elevation is about 30,000 English feet (almost twice that of Mont
Blanc), or, at any rate, 29,000 feet (see Captain Alexander Gerard's and
John Gerard's 'Journey to the Boorendo Pass', 1840, vol. i., p. 143 and
311). Chimborazo is spoken of in the text only as 'one' of the highest
summits of the chain of the Andes; for in the year 1827, the learned and
highly-gifted traveler, Pentland, in his memorable expedition to Upper Peru
(Bolivia), measured the elevation of two mountains situated to the east of
Lake Titicaca, viz., the Sorata, 25,200 feet, and the Illimani, 24,000 feet,
both greatly exceeding the height of Chimborazo, which is only 21,421 feet,
and being nearly equal in elevation to the Jawahir, which is the highest
mountain in the Himalaya that has as yet been accurately measured. Thus
Mont Blanc is 5646 feet below Chimborazo; Chimborazo, 3779 feet below the
Sorata; the Sorata, 549 feet below the Jawahir, and probably about 2880 feet
below the Dhawalagiri. According to a new measurement of the Illimani, by
Pentland, in 1838, the elevation of this mountain is given at 23,868 feet,
varying only 133 feet from the measurement taken in 1827. The elevations
have been given in this note with minute exactness, as erroneous numbers
have been introduced into many maps and tables recently published, owing to
incorrect reductions of the measurements.
[In the preceding note, taken from those appended to the Introduction in the
French translation, rewritten by Humboldt himself, the measurements are
given in meters, but these have been converted into English feet, for the
greater convenience of the general reader.] -- 'Tr.'
But although the mountains of India greatly surpass the Cordilleras of South
America by their astonishing elevation (which, after being long contested,
has at last been confirmed by accurate measurements), they can not, from
their geographical position, present the same inexhaustible variety of
phenomena by which the latter are characterized. The impression produced by
the grander aspects of nature dies not depend exclusively on height. The
chain of the Himalaya is placed far beyond the limits of the torrid zone,
and scarcely is a solitary palm-tree to be found in the beautiful valleys of
Kumaoun and Garhwal.*
[Footnote] *The absence of palms and tree-ferns on the temperate slopes of
the Himalaya is shown in Don's 'Flora Nepalensis', 1825, and in the
remarkable series of lithographs of Wallich's 'Flora Indica', whose
catalogue contains the enormous number of 7683 Himalaya species, almost all
phanerogamic plants, which have as yet been but imperfectly classified. In
Nepaul (lat. 26 1/2 degrees to 27 1/4 degrees) there has hitherto been
observed only one species of palm, Chamaerops martiana, Wall. ('Plantae
Asiat.', lib. iii., p. 5,211), which is found at the height of 5250 English
feet above the level of the sea, in the shady valley of Bunipa. The
magnificent tree-fern, Alsophila brunoniana, Wall. (of which a stem 48 feet
long has been in the possession of the British Museum since 1831), does not
grow in Nepaul, but is found on the mountains of Silhet, to the northwest of
Calcutta, in lat. 24 degrees 50 minutes. The Nepaul fern, Paranema
cyathoides, Don, formerly known as Sphaeroptera barbata, Wall. ('Plantae
Asiat.', lib. i., p. 42, 48), is indeed, nearly related to Cyathea, a
species of which I have seen in the South American Missions of Caripe,
measuring 33 feet in height; this is not, however, properly speaking a tree.
On the southern slope of the ancient Paropamisus, in the latitudes of 28
degrees and 34 degrees, nature no longer displays the same abundance of
tree-ferns and arborescent grasses, heliconias and orchideous plants, which
in tropical
p 30
regions are to be found even on the highest plateaux of the mountains. On
the slope of the Himalaya, under the shade of the Deodora and the
broad-leaved oak, peculiar to these Indian Alps, the rocks of granite and of
mica schist are covered with vegetable forms almost similar to those which
characterize Europe and Northern Asia. The species are not identical, but
closely analogous in aspect and physiognomy, as, marsh parnassia, and the
prickly species of Ribes.* The chain of the Himalaya is also wanting in the
imposing phenomena of volcanoes, which in the Andes and in the Indian
Archipelago often reveal to the inhabitants, under the most terrific forms,
the existence of the forces pervading the interior of our planet.
[footnote] *Ribes nubicola, R. glaciale, R. grossularia. The species which
compose the vegetation of the Himalaya are four pines, notwithstanding the
assertion of the ancients regarding Eastern Asia (Strabo, lib. 11, p. 510,
Cas.), twenty-five oaks, four birches, two chestnuts, seven maples, twelve
willows, fourteen roses, three species of strawberry, seven species of
Alpine roses ('rhododendra'), one of which attains a height of 20 feet, and
many other northern genera. Large white apes, having black faces, inhabit
the wild chestnut-tree of Kashmir, which grows to a height of 100 feet, in
lat. 33 degrees (see Carl von Hugel's 'Kaschmir', 1840, 2d pt. 249). Among
the Coniferae, we find the Pinus deodwara, or deodara (in Sanscrit,
'dewa-daru', the timber of the gods), which is nearly allied to Pinus
cedrus. Near the limit of perpetual snow flourish the large and showy
flowers of the Gentiana venusta, G. Moorcroftiana, Swertia purpurescens, S.
speciosa, Parnassia armata, P. nubicola, Poenia Emode, Tulipa stellata; and
besides varieties of European genera peculiar to these Indian mountains,
true European species as Leontodon taraxacum, Prunella vulgaris, Galium
aparine, and Thlaspi arvense. The heath mentioned by Saunders, in Turner's
'Travels', and which had been confounded with Calluna vulgaris, is an
Andromeda, a fact of the greatest importance in the geography of Asiatic
plants. If I have made use, in this work, of the unphilosophical
expressions of European genera, 'European' special, 'growing wild in Asia',
etc., it has been in consequence of the old botanical language, which,
instead of the idea of a large dissemination, or, rather, of the coexistence
of organic productions, has dogmatically substituted the false hypothesis of
a migration, which, from predilection for Europe, is further assumed to have
been from west to east.
Moreover, on the southern declivity of the Himalaya, where the ascending
current deposits the exhalations rising from a vigorous Indian vegetation,
the region of perpetual snow begins at an elevation of 11,000 or 12,000 feet
above the level of the sea,* thus setting a limit to the development of
organic
p 31
life in a zone that is nearly 3000 feet lower than that to which it attains
in the equinoctial region of the Cordilleras.
[footnote] *On the southern declivity of the Himalaya, the limit of
perpetual snow is 12,978 feet above the level of the sea; on the northern
declivity, or, rather, on the peaks which rise above the Thibet, or
Tartarian plateau, this limit is at 16,625 feet from 30 1/2 degrees to 32
degrees of latitude, while at the equator, in the Andes of Quito, it is
15,790 feet. Such is the result I have deduced from the combination of
numerous data furnished by Webb, Gerard, Herbert, and Moorcroft. (See my
two memoirs on the mountains of India, in 1816 and 1820, in the 'Ann. de
Chimie et de Physique', t. iii., p. 303; t. xiv., p. 6, 22, 50.) The
greater elevation to which the limit of perpetual snow recedes on the
Tartarian declivity is owing to the radiation of heat from the neighboring
elevated plains, to the purity of the atmosphere, and to the infrequent
formation of snow in an air which is both very cold and very dry.
(Humboldt, 'Asie Centrale', t. iii., p. 281-326.) My opinion on the
difference of height of the snow-line on the two sides of the Himalaya has
the high authority of Colebrooke in its favor. He wrote to me in June,
1824, as follows: "I also find, from the data in my possession, that the
elevation of the line of perpetual snow is 13,000 feet. On the southern
declivity, and at latitude 31 degrees, Webb's measurements give me 13,500
feet, consequently 500 feet more than the height deduced from Captain
Hodgson's observations. Gerard's measurements fully confirm your opinion
that the line of snow is higher on the northern than on the southern side."
It was not until the present year (1840) that we obtained the complete and
collected journal of the brothers Gerard, published under the supervision of
Mr. Lloyd. ('Narrative of a Journey from Cawnpoor to the Boorendo Pass, in
the Himalaya, by Captain Alexander Gerard and John Gerard, edited by George
Lloyd', vol. i., p. 292, 311, 320, 327 and 341.) Many interesting details
regarding some localities may be found in the narrative of 'A Visit to the
Shatool, for the Purpose of determining the Line of Perpetual Snow on the
southern face of the Himalaya, in August', 1822. Unfortunately, however,
these travelers always confound the elevation at which sporadic snow falls
with the maximum of the height that the snow-line attains on the Thibetian
plateau. Captain Gerard distinguishes between the summits that rise in the
middle of the plateau, where he states the elevation of the snow-line to be
between 18,000 and 19,000 feet, and the northern slopes of the chain of the
Himalaya, which border on the defile of the Sutledge, and can radiate but
little heat, owing to the deep ravines with which they are intersected. The
elevation of the village of Tangno is given at only 9300 feet, while that of
the plateau surrounding the sacred lake of Maqasa is 17,000 feet. Captain
Gerard finds the snow-line 500 feet lower on the northern slopes, where the
chain of the Himalaya is broken through, than toward the southern
declivities facing Hindostan, and he there estimates the line of perpetual
snow at 15,000 feet. The most striking differences are presented between
the vegetation on the Thibetian plateau and that characteristic of the
southern slopes of the Himalaya. On the latter the cultivation of grain is
arrested at 9974 feet and even there the corn has often to be cut when the
blades are still green. The extreme limit of forests of tall oaks and
deodars is 11,960 feet; that of dwarf birches, 12,983 feet. On the plains,
Captain Gerard found pastures up to the height of 17,000 feet; the cereals
will grow at 14,100 feet, or even at 18,540 feet; birches with tall stems at
14,100 feet, and copse or brush wood applicable for fuel is found at an
elevation of upward of 17,000 feet, that is to say, 1280 feet and above the
lower limits of the snow-line at the equator, in the province of Quito. It
is very desirable that the 'mean' elevation of the Thibetian plateau, which
I have estimated at only about 8200 feet between the Himalaya and the
Kuen-lun, and the difference in the height of the line of perpetual snow on
the southern and on the northern slopes of the Himalaya, should be again
investigated by travelers who are accustomed to judge of the general
conformation of the land. Hitherto simple calculations have too often been
confounded with actual measurements, and the elevations of isolated summits
with that of the surrounding plateau. (Compare Carl Zimmerman's excellent
Hypsometrical Remarks in his 'Geographischen Analyse der Karte von Inner
Asien', 1841, s. 98.) Lord draws attention to the difference presented by
the two faces of the Himalaya and those of the Alpine chain of Hindoo-Coosh,
with respect to the limits of the snow-line. "The latter chain," he says,
"has the table-land to the south, in consequence of which the snow-line is
higher on the southern side, contrary to what we find to be the case with
respect to the Himalaya, which is bounded on the south by sheltered plains,
as Hindoo-Coosh is on the north." It must, however, be admitted that the
hypsometrical data on which these statements are based require a critical
revision with regard to several of their details; but still they suffice to
establish the main fact, that the remarkable configuration of the land in
Central Asia affords man all that is essential to the maintenance of life,
as habitation, food, and fuel, at an elevation above the level of the sea
which in almost all other parts of the globe is covered with perpetual ice.
We must except the very dry districts of Bolivia, where snow is so rarely
met with, and where Pentland (in 1838) fixed the snow-line at 15,667 feet,
between 16 degrees and 17 3/4 degrees south latitude. The opinion that I
had advanced regarding the difference in the snow-line on the two faces of
the Himalaya has been most fully confirmed by the barometrical observations
of Victor Jacquemont, who fell an early sacrifice to his noble and unwearied
ardor. (See his 'Correspondance pendant son Voyage dans l'Inde', 1828 'a'
1832, liv. 23, p. 290, 296, 299.) "Perpetual snow," says Jacquemont,
"descends lower on the southern than on the northern slopes of the Himalaya,
and the limit constantly rises as we advance to the north of the chain
bordering on India. On the Kionbrong, about 18,317 feet in elevation,
according to Captain Gerard, I was still considerably below the limit of
perpetual snow which I believe to be 19,690 feet in this part of Hindostan."
(This estimate I consider much too high.)
[Footnote continues] The same traveler says, "To whatever height we rise on
the southern declivity of the Himalaya, the climate retains the same
character, and the same division of the seasons as in the plains of India;
the summer solstice being every year marked by the same prevalence of rain
which continues to fall without intermission until the autumnal equinox.
But a new, a totally different climate begins at Kashmir, whose elevation I
estimate to be 5350 feet, nearly equal to that of the cities of Mexico and
Popayan" ('Correspond. de Jacquemont', t. ii., p. 58 et 74). The warm and
humid air of the sea, as Leopold von Buch well observes, is carried by the
monsoons across the plains of India to the skirts of the Himalaya which
arrest its course, and hinder it from diverging to the Thibetian districts
of Ladak and Lassa. Carl von Hugel estimates the elevation of the Valley of
Kashmir above the level of the sea at 5818 feet, and bases his observation
on the determination of the boiling point of water (see theil 11, s. 155,
and 'Journal of Geog. Soc.', vol. vi., p. 215). In this valley, where the
atmosphere is scarcely ever agitated by storms, and in 34 degrees 7 minutes
lat., snow is found, several feet in thickness, from December to March.
p 32
But the countries bordering on the equator possess another advantage, to
which sufficient attention has not hitherto been
p 33
directed. This portion of the surface of the globe affords in the smallest
space the greatest possible variety of impressions from the contemplation of
nature. Among the colossal mountains of Cundinamarea, of Quito, and of
Peru, furrowed by deep ravines, man is enabled to contemplate alike all the
families of plants, and all the stars of the firmament. There, at a single
glance, the eye surveys majestic palms, humid forests of bambusa, and the
varied species of Musaceae, while above these forms of tropical vegetation
appear oaks, medlars, the sweet-brier, and umbelliferous plants, as in our
European homes. There as the traveler turns his eyes to the vault of
heaven, a single glance embraces the constellation of the Southern Cross,
the Magellanic clouds, and the guiding stars of the constellation of the
Bear, as they circle round the arctic pole. There the depths of the earth
and the vaults of heaven display all the richness of their forms and the
variety of their phenomena. There the different climates are ranged the one
above the other, stage by stage, like the vegetable zones, whose succession
they limit; and there the observer may readily trace the laws that regulate
the diminution of heat, as they stand indelibly inscribed on the rocky walls
and abrupt declivities of the Cordilleras.
Not to weary the reader with the details of the phenomena which I long since
endeavored graphically to represent,* I will here limit myself to the
consideration of a few of the general results whose combination constitutes
the 'physical delineation of the torrid zone.' That which, in the vagueness
of our
p 34
impressions, loses all distinctness of form, like some distant mountain
shrouded from view by a vail of mist, is clearly revealed by the light of
mind, which, by its scrutiny into the causes of phenomena, learns to resolve
and analyze their different elements, assigning to each its individual
character. Thus, in the sphere of natural investigation, as in poetry and
painting, the delineation of that which appeals most strongly to the
imagination, derives its collective interest from the vivid truthfulness
with which the individual features are portrayed.
[footnote] *See, generally my 'Essai sur la Geographie des Plantes, et le
Tableau physique des Regions Equinoxiales', 1807, p. 80-88. On the diurnal
and nocturnal variations of temperature, see Plate 9 of my 'Atlas Geogr. et
Phys. du Nouveau Continent'; and the Tables in my work, entitled 'De
distributione Geographica Plantarum, secundum coeli tempriem, et altitudinem
Montium', 1817, p. 90-116; the meteorological portion of my 'Asie Centrale',
t. iii., p. 212, 224; and, finally, the more recent and far more exact
exposition of the variations of temperature experienced in correspondence
with the increase of altitude on the chain of the Andes, given in
Boussingault's Memoir, 'Sur la profondeur a laquelle on trouve, sous les
Tropiques, la couche de Temperature Invariable.' (Ann. de Chimie et de
Physique, 1833, t. liii., p. 225-247.) This treatise contains the
elevations of 128 points, included between the level of the sea and the
declivity of the Antisana (17,900 feet), as well as the mean temperature of
the atmosphere, which varies with the height between 81 degrees and 35
degrees F.
The regions of the torrid zone not only give rise to the most powerful
impressions by their organic richness and their abundant fertility, but they
likewise afford the inestimable advantage of revealing to man, by the
uniformity of the variations of the atmosphere and the development of vital
forces, and by the contrasts of climate and vegetation exhibited at the
different elevations, the invariability of the laws that regulate the course
of the heavenly bodies, reflected, as it were, in terrestrial phenomena.
Let us dwell, then, for a few moments, on the proofs of this regularity,
which is such that it may be submitted to numerical calculation and
computation.
In the burning plains that rise but little above the level of the sea, reign
the families of the banana, the cycas, and the palm, of which the number of
species comprised in the flora of tropical regions has been so wonderfully
increased in the present day by the zeal of botanical travelers. To these
groups succeed, in the Alpine valleys, and the humid and shaded clefts on
the slopes of the Cordilleras, the tree-ferns, whose thick cylindrical
trunks and delicate lace-like foliage stand out in bold relief against the
azure of the sky, and the cinchona, from which we derive the febrifuge bark.
The medicinal strength of this bark is said to increase in proportion to
the degree of moisture imparted to the foliage of the tree by the light
mists which form the upper surface of the clouds resting over the plains.
Every where around, the confines of the forest are encircled by broad bands
of social plants, as the delicate aralia, the thibaudia, and the
myrtle-leaved Andromeda, while the Alpine rose, the magnificent befaria,
weaves a purple girdle round the spiry peaks. In the cold regions of the
Paramos, which is continually exposed to the fury of storms and winds, we
find that flowering shrubs and herbaceous plants, bearing large and
variegated blossoms, have given place to monocotyledons, whose slender
spikes constitute the sole covering of the soil. This is the zone of the
p 35
grasses, one vast savannah extending over the immense mountain plateaux, and
reflecting a yellow, almost golden tinge, to the slopes of the Cordilleras,
on which graze the lama and the cattle domesticated by the European
colonist. Where the naked trachyte rock pierces the grassy turf, and
penetrates into those higher strata of air which are supposed to be less
charged with carbonic acid, we meet only with plants of an inferior
organization, as lichens, lecideas, and the brightly-colored, dust-like
lepraria, scattered around in circular patches. Islets of fresh-fallen
snow, varying in form and extent, arrest the last feeble traces of vegetable
development, and to these succeeds the region of perpetual snow, whose
elevation undergoes but little change, and may be easily determined. It is
but rarely that the elastic forces at work within the interior of our globe
have succeeded in breaking through the spiral domes, which, resplendent in
the brightness of eternal snow, crown the summits of the Cordilleras; and
even where these subterranean forces have opened a permanent communication
with the atmosphere, through circular craters or long fissures, they rarely
send forth currents of lava, but merely eject ignited scoriae, steam,
sulphureted hydrogen gas, and jets of carbonic acid.
In the earliest stages of civilization, the grand and imposing spectacle
presented to the minds of the inhabitants of the tropics could only awaken
feelings of astonishment and awe. It might, perhaps, be supposed, as we
have already said, that the periodical return of the same phenomena, and the
uniform manner in which they arrange themselves in successive groups, would
have enabled man more readily to attain to a knowledge of the laws of
nature; but, as far as tradition and history guide us, we do not find that
any application was made of the advantages presented by these favored
regions. Recent researches have rendered it very doubtful whether the
primitive seat of Hindoo civilization -- one of the most remarkable phases
in the progress of mankind -- was actually within the tropics. Airyana
Vaedjo, the ancient cradle of the Zend, was situated to the northwest of the
upper Indus, and after the great religious schism, that is to say, after the
separation of the Iranians from the Brahminical institution, the language
that had previously been common to them and to the Hindoos assumed among the
latter people (together with the literature, habits, and conditions of
society) an individual form in the Magodha of Madhya Desa,* a district that
is bounded by the great chain
p 36
of Himalaya and the smaller range of the Vindhya.
[footnote] *See, on the Madhjadeca, properly so called, Lassen's excellent
work, entitled 'Indische Alterthumskunde', bd. i., s. 92. The Chinese give
the name of Mo-kie-thi to the southern Bahar, situated to the south of the
Ganges (see 'Foe-Koue-Ki' by, 'Chy-Fa-Hian', 1836, p. 256). Djambu-dwipa is
the name given to the whole of India; but the words also indicate one of the
four Buddhist continents.
In less ancient times the Sanscrit language and civilization advanced toward
the southeast, penetrating further within the torrid zone, as my brother
Wilhelm von Humboldt has shown in his great work on the Kavi and other
languages of analogous structure.*
[Footnote] *'Ueber die Kawi Sprache auf der Insel Java, nebst einer
Einleitung uber die Verschiedenheit des menschlichen Sprachbaues und ihren
Ein fluss auf die geistige Entwickelung des Menschengrshlecht's' von Wilhelm
v. Humboldt, 1836, bd. i., s. 50519.
Notwithstanding the obstacles opposed in northern latitudes to the discovery
of the laws of nature, owing to the excessive complication of phenomena, and
the perpetual local variations and the distribution of organic forms, it is
to the inhabitants of a small section of the temperate zone that the rest of
mankind owe the earliest revelation of an intimate and rational acquaintance
with the forces governing the physical world. Moreover, it is from the same
zone (which is apparently more favorable to the progress of reason, the
softening of manners, and the security of public liberty) that the germs of
civilization have been carried to the regions of the tropics, as much by the
migratory movement of races as by the establishment of colonies, differing
widely in their institution from those of the Phoenicians or Greeks.
In speaking of the influence exercised by the succession of phenomena on the
greater or lesser facility of recognizing the causes producing them, I have
touched upon that important stage of our communion with the external world,
when the enjoyment arising from a knowledge of the laws, and the mutual
connection of phenomena, associates itself with the charm of a simple
contemplation of nature. That which for a long time remains merely an
object of vague intuition, by degrees acquires the certainty of positive
truth; and man, as an immortal poet has said, in our own tongue -- Amid
ceaseless change seeks the unchanging pole.*
[Footnote] *This verse occurs in a poem of Schiller, entitled 'Der
Spaziergang' which first appeared in 1795, in the 'Horen.'
In order to trace to its primitive source the enjoyment derived from the
exercise of thought, it is sufficient to cast a rapid glance on the earliest
dawnings of the philosophy of nature, or of the ancient doctrine of the
'Cosmos.' We find even
p 37
among the most savage nations (as my own travels enable me to attest) a
certain vague, terror-stricken sense of the all-powerful unity of natural
forces, and of the existence of an invisible, spiritual essence manifested
in these forces, whether in unfolding the flower and maturing the fruit of
the nutrient tree, in upheaving the soil of the forest, or in rending the
clouds with the might of the storm. We may here trace the revelation of a
bond of union, linking together the visible world and that higher spiritual
world which escapes the grasp of the senses. The two become unconsciously
blended together, developing in the mind of man, as a simple product of
ideal conception and independently of the aid of observation, the first germ
of a 'Philosophy of Nature.'
Among nations least advanced in civilization, the imagination revels in
strange and fantastic creations, and, by its predilection for symbols, alike
influences ideas and language. Instead of examining, men are led to
conjecture, dogmatize, and interpret supposed facts that have never been
observed. The inner world of thought and of feeling does not reflect the
image of the external world in its primitive purity. That which in some
regions of the earth manifested itself as the rudiments of natural
philosophy, only to a small number of persons endowed with superior
intelligence, appears in other regions, and among entire races of men, to be
the result of mystic tendencies and instinctive intuitions. An intimate
communion with nature, and the vivid and deep emotions thus awakened, are
likewise the source from which have sprung the first impulses toward the
worship and deification of the destroying and preserving forces of the
universe. But by degrees, as man, after having passed through the different
gradations of intellectual development, arrives at the free enjoyment of the
regulating power of reflection, and learns by gradual progress, as it were,
to separate the world of ideas from that of sensations, he no longer rests
satisfied merely with a vague presentiment of the harmonious unity of
natural forces; thought begins to fulfill its noble mission; and
observation, aided by reason, endeavors to trace phenomena to the causes
from which they spring.
The history of science teaches us the difficulties that have opposed the
progress of this active spirit of inquiry. Inaccurate and imperfect
observations have led, by false inductions, to the great number of physical
views that have been perpetuated as popular prejudices among all classes of
society. Thus by the side of a solid and scientific knowledge of natural
phenomena there has been preserved a system of the pretended
p 38
results of observation, which is so much the more difficult to shake, as it
denies the validity of the facts by which it may be refuted. This
empiricism, the melancholy heritage transmitted to us from former times,
invariably contends for the truth of its axioms with the arrogance of a
narrow-minded spirit. Physical philosophy, on the other hand, when based
upon science, doubts because it seeks to investigate, distinguishes between
that which is certain and that which is merely probable, and strives
incessantly to perfect theory by extending the circle of observation.
This assemblage of imperfect dogmas, bequeathed by one age to another --
this physical philosophy, which is composed of popular prejudices -- is not
only injurious because it perpetuates error with the obstinacy engendered by
the evidence of ill-observed facts, but also because it hinders the mind
from attaining to higher views of nature. Instead of seeking to discover
the 'mean' or 'medium' point, around which oscillate, in apparent
independence of forces, all the phenomena of the external world, this system
delights in multiplying exceptions to the law, and seeks, amid phenomena and
in organic forms for something beyond the marvel of a regular succession,
and an internal and progressive development. Ever inclined to believe that
the order of nature is disturbed, it refuses to recognize in the present any
analogy with the past, and guided by its own varying hypotheses, seeks at
hazard, either in the interior of the globe or in the regions of space, for
the cause of these pretended perturbations.
It is the special object of the present work to combat those errors which
derive their source from a vicious empiricism and from imperfect inductions.
The higher enjoyments yielded by the study of nature depend upon the
correctness and the depth of our views, and upon the extent of the subjects
that may be comprehended in a single glance. Increased mental cultivation
has given rise, in all classes of society, to an increased desire of
embellishing life by augmenting the mass of ideas, and by multiplying means
for their generalization; and this sentiment fully refutes the vague
accusations advanced against the age in which we live, showing that other
interests, besides the material wants of life, occupy the minds of men.
It is almost with reluctance that I am about to speak of a sentiment, which
appears to arise from narrow-minded views, or from a certain weak and morbid
sentimentality -- I allude to the 'fear' entertained by some persons, that
nature may by degrees lose a portion of the charm and magic of her power,
p 39
as we learn more and more how to unvail her secrets, comprehend the
mechanism of the movements of the heavenly bodies, and estimate numerically
the intensity of natural forces. It is true that, properly speaking, the
forces of nature can only exercise a magical power over us as long as their
action is shrouded in mystery and darkness, and does not admit of being
classed among the conditions with which experience has made us acquainted.
The effect of such a power is, therefore, to excite the imagination, but
that, assuredly, is not the faculty of mind we would evoke to preside over
the laborious and elaborate observations by which we strive to attain to a
knowledge of the greatness and excellence of the laws of the universe.
The astronomer who, by the aid of the heliometer or a double-refracting
prism,* determines the diameter of planetary bodies; who measures patiently
year after year, the meridian altitude and the relative distances of stars,
or who seeks a telescopic comet in a group of nebulae, does not feel his
imagination more excited -- and this is the very guarantee of the precision
of his labors -- than the botanist who counts the divisions of the calyx, or
the number of stamens in a flower, or examines the connected or the separate
teeth of the peristoma surrounding the capsule of a moss. Yet the
multiplied angular measurements on the one hand, and the detail of organic
relations on the other, alike aid in preparing the way for the attainment of
higher views of the laws of the universe.
[Footnote] *Arago's ocular micrometer, a happy improvement upon Rochon's
prismatic or double-refraction micrometer. See M. Mathieu's note in
Delambre's 'Histoire de l'Astronomie au dix-huitieme Siecle', 1827.
We must not confound the disposition of mind in the observer at the time he
is pursuing his labors, with the ulterior greatness of the views resulting
from investigation and the exercise of thought. The physical philosopher
measures with admirable sagacity the waves of light of unequal length which
by interference mutually strengthen or destroy each other, even with respect
to their chemical actions; the astronomer, armed with powerful telescopes,
penetrates the regions of space, contemplates, on the extremest confines of
our solar system, the satellites of Uranus, or decomposes faintly sparkling
points into double stars differing in color. The botanist discovers the
constancy of the gyratory motion of the chara in the greater number of
vegetable cells, and recognizes in the genera and natural families of plants
the intimate relations or organic forms. The vault of heaven, studded with
nebulae
p 40
and stars, and the rich vegetable mantle that covers the soil in the climate
of palms, can not surely fail to produce on the minds of these laborious
observers of nature an impression more imposing and more worthy of the
majesty of creation than on those who are unaccustomed to investigate the
great mutual relations of phenomena. I can not, therefore, agree with Burke
when he says, "it is our ignorance of natural things that causes all our
admiration and chiefly excites our passions."
While the illusion of the senses would make the stars stationary in the
vault of heaven, Astronomy, by her aspiring labors, has assigned indefinite
bounds to space; and if she have set limits to the great nebula to which our
solar system belongs, it has only been to show us in those remote regions of
our optic powers, islet on islet of scattered nebulae. The feeling of the
sublime, so far as it arises from a contemplation of the distance of the
stars, of their greatness and physical extent, reflects itself in the
feeling of the infinite, which belongs to another sphere of ideas included
in the domain of mind. The solemn and imposing impressions excited by this
sentiment are owing to the combination of which we have spoken, and to the
analogous character of the enjoyment and emotions awakened in us, whether we
float on the surface of the great deep, stand on some lonely mountain summit
enveloped in the half-transparent vapory vail of the atmosphere, or by the
aid of powerful optical instruments scan the regions of space, and see the
remote nebulous mass resolve itself into worlds of stars.
The mere accumulation of unconnected observations of details, devoid of
generalization of ideas, may doubtlessly have tended to create and foster
the deeply-rooted prejudice, that the study of the exact sciences must
necessarily chill the feelings, and diminish the nobler enjoyments attendant
upon a contemplation of nature. Those who still cherish such erroneous
views in the present age, and amid the progress of public opinion, and the
advancement of all branches of knowledge, fail in duly appreciating the
value of every enlargement of the sphere of intellect, and the importance of
the detail of isolated facts in leading us on to general results. The fear
of sacrificing the free enjoyment of nature, under the influence of
scientific reasoning, is often associated with an apprehension that every
mind may not be capable of grasping the truths of the philosophy of nature.
It is certainly true that in the midst of the universal fluctuation of
phenomena and vital
p 41
forces -- in that inextricable net-work of organisms by turns developed and
destroyed -- each step that we make in the more intimate knowledge of nature
leads us to the entrance of new labyrinths; but the excitement produced by a
presentiment of discovery, the vague intuition of the mysteries to be
unfolded, and the multiplicity of the paths before us, all tend to stimulate
the exercise of thought in every stage of knowledge. The discovery of each
separate law of nature leads to the establishment of some other more general
law, or at least indicates to the intelligent observer its existence.
Nature, as a celebrated physiologist* has defined it, and as the word was
interpreted by the Greeks and Romans, is "that which is ever growing and
ever unfolding itself in new forms."
[Footnote] *Carus, 'Von den Urtheilen des Knochen und Schalen Gerustes',
1828 6.
The series of organic types becomes extended or perfected in proportion as
hitherto unknown regions are laid open to our view by the labors and
researches of travelers and observers; as living organisms are compared with
those which have disappeared in the great revolutions of our planet; and as
microscopes are made more perfect, and are more extensively and efficiently
employed. In the midst of this immense variety, and this periodic
transformation of animal and vegetable productions, we see incessantly
revealed the primordial mystery of all organic development, that same great
problem of 'metamorphosis' which GÂthe has treated with more than common
sagacity, and to the solution of which man is urged by his desire of
reducing vital forms to the smallest number of fundamental types. As men
contemplate the riches of nature, and see the mass of observations
incessantly increasing before them, they become impressed with the intimate
conviction that the surface and the interior of the earth, the depths of the
ocean, and the regions of air will still, when thousands and thousands of
years have passed away, open to the scientific observer untrodden paths of
discovery. The regret of Alexander can not be applied to the progress of
observation and intelligence.*
[footnote] * Plut., in 'Vita Alex. Magni', cap. 7
General considerations, whether they treat of the agglomeration of matter in
the heavenly bodies, or of the geographical distribution of terrestrial
organisms, are not only in themselves more attractive than special studies,
but they also afford superior advantages to those who are unable to devote
much time to occupations of this nature. The different branches of the
study of natural history are only accessible in certain positions of social
life, and do not, at every season
p 42
and in every climate, present like enjoyments. Thus, in the dreary regions
of the north, man is deprived for a long period of the year of the spectacle
presented by the activity of the productive forces of organic nature; and if
the mind be directed to one sole class of objects, the most animated
narratives of voyages in distant lands will fail to interest and attract us,
if they do not touch upon the subjects to which we are most partial.
As the history of nations -- if it were always able to trace events to their
true causes -- might solve the ever-recurring enigma of the oscillations
experienced by the alternately progressive and retrograde movement of human
society, so might also the physical description of the world, the science of
the 'Cosmos', if it were grasped by a powerful intellect, and based upon a
knowledge of all the results of discovery up to a given period, succeed in
dispelling a portion of the contradictions which, at first sight, appear to
arise from the complication or phenomena and the multitude of the
perturbations simultaneously manifested.
The knowledge of the laws of nature, whether we can trace them in the
alternate ebb and flow of the ocean, in the measured path of comets, or in
the mutual attractions of multiple stars, alike increases our sense of the
calm of nature, while the chimera so long cherished by the human mind in its
early and intuitive contemplations, the belief in a "discord of the
elements," seems gradually to vanish in proportion as science extends her
empire. General views lead us habitually to consider each organism as a
part of the entire creation, and to recognize in the plant or the animal not
merely an isolated species, but a form linked in the chain of being to other
forms either living or extinct. They aid us in comprehending the relations
that exist between the most recent discoveries and those which have prepared
the way for them. Although fixed to one point of space, we eagerly grasp at
a knowledge of that which has been observed in different and far-distant
regions. We delight in tracking the course of the bold mariner through seas
of polar ice, or in following him to the summit of that volcano of the
antarctic pole, whose fires may be seen from afar, even at mid-day. It is
by an acquaintance with the results of distant voyages that we may learn to
comprehend some of the marvels of terrestrial magnetism, and be thus led to
appreciate the importance of the establishments of the numerous
observatories which in the present day cover both hemispheres, and are
designed to note
p 43
the simultaneous occurrence of perturbations, and the frequency and duration
of 'magnetic storms.'
Let me be permitted here to touch upon a few points connected with
discoveries, whose importance can only be estimated by those who have
devoted themselves to the study of the physical sciences generally.
Examples chosen from among the phenomena to which special attention has been
directed in recent times, will throw additional light upon the preceding
considerations. Without a preliminary knowledge of the orbits of comets, we
should be unable duly to appreciate the importance attached to the discovery
of one of these bodies, whose elliptical orbit is included in the narrow
limits of our solar system, and which has revealed the existence of an
ethereal fluid, tending to diminish its centrifugal force and the period of
its revolution.
The superficial half-knowledge, so characteristic of the present day, which
leads to the introduction of vaguely comprehended scientific views into
general conversation, also gives rise, under various forms, to the
expression of alarm at the supposed danger of a collision between the
celestial bodies, or of disturbance in the climatic relations of our globe.
These phantoms of the imagination are so much the more injurious as they
derive their source from dogmatic pretensions to true science. The history
of the atmosphere, and of the annual variations of its temperature, extends
already sufficiently far back to show the recurrence of slight disturbances
in the mean temperature of any given place, and thus affords sufficient
guarantee against the exaggerated apprehension of a general and progressive
deterioration of the climates of Europe. Encke's comet, which is one of the
three 'interior comets', completes its course in 1200 days, but from the
form and position of its orbit it is as little dangerous to the earth as
Halley's great comet, whose revolution is not completed in less than
seventy-six years (and which appeared less brilliant in 1835 than it had
done in 1759): the interior comet of Biela intersects the earth's orbit, it
is true, but it can only approach our globe when its proximity to the sun
coincides with our winter solstice.
The quantity of heat received by a planet, and whose unequal distribution
determines the meteorological variations of its atmosphere, depends alike
upon the light-engendering force of the sun; that is to say, upon the
condition of its gaseous coverings, and upon the relative position of the
planet and the central body.
p 44
There are variations, it is true, which, in obedience to the laws of
universal gravitation, affect the form of the earth's orbit and the
inclination of the ecliptic, that is, the angle which the axis of the earth
makes with the plane of its orbit; but these periodical variations are so
slow, and are restricted within such narrow limits, that their thermic
effects would hardly be appreciable by our instruments in many thousands of
years. The astronomical causes of a refrigeration of our globe, and of the
diminution of moisture at its surface, and the nature and frequency of
certain epidemics -- phenomena which are often discussed in the present day
according to the benighted views of the Middle Ages -- ought to be
considered as beyond the range of our experience in physics and chemistry.
Physical astronomy presents us with other phenomena, which can not be fully
comprehended in all their vastness without a previous acquirement of general
views regarding the forces that govern the universe. Such, for instance,
are the innumerable double stars, or rather suns, which revolve round one
common center of gravity, and thus reveal in distant worlds the existence of
the Newtonian law; the larger or smaller number of spots upon the sun, that
is to say, the openings formed through the luminous and opaque atmosphere
surrounding the solid nucleus; and the regular appearance about the 13th of
November and the 11th of August, of shooting stars, which probably form part
of a belt of asteroids, intersecting the earth's orbit, and moving with
planetary velocity.
Descending from the celestial regions to the earth, we would fain inquire
into the relations that exist between the oscillations of the pendulum in
air (the theory of which has been perfected by Bessel) and the density of
our planet; and how the pendulum, acting the part of a plummet, can, to a
certain extent, throw light upon the geological constitution of strata at
great depths? By means of this instrument we are enabled to trace the
striking analogy which exists between the formation of the granular rocks
composing the lava currents ejected from active volcanoes, and those
endogenous masses of granite, porphyry, and serpentine, which, issuing from
the interior of the earth, have broken, as eruptive rocks, through the
secondary strata, and modified them by contact, either in rendering them
harder by the introduction of silex, or reducing them into dolomite, or,
finally, by inducing within them the formation of crystals of the most
varied composition. The elevation of sporadic islands, of
p 45
domes of trachyte, and cones of basalt, by the elastic forces emanating from
the fluid interior of our globe, has led one of the first geologists of the
age, Leopold von Buch, to the theory of the elevation of continents, and of
mountain chains generally. This action of subterranean forces in breaking
through and elevating strata of sedimentary rocks, of which the coast of
Chili, in consequence of a great earthquake, furnished a recent example,
leads to the assumption that the pelagic shells found by M. Bonpland and
myself on the ridge of the Andes, at an elevation of more than 15,000
English feet, may have been conveyed to so extraordinary a position, not by
a rising of the ocean, but by the agency of volcanic forces capable of
elevating into ridges the softened crust of the earth.
I apply the term 'volcanic', in the widest sense of the word, to every
action exercised by the interior of a planet on its external crust. The
surface of our globe, and that of the moon, manifest traces of this action,
which in the former, at least, has varied during the course of ages. Those
who are ignorant of the fact that the internal heat of the earth increases
so rapidly with the increase of depth that granite is in a state of fusion
about twenty or thirty geographical miles below the surface,* can not have a
clear conception of the causes, and the simultaneous occurrence of volcanic
eruptions at places widely removed from one another, or of the extent and
intersection of 'circles of commotion' in earthquakes, or of the uniformity
of temperature, and equality of chemical composition observed in thermal
springs during a long course of years.
[Footnote] * The determinations usually given of the point of fusion are in
general much too high for refracting substances. According to the very
accurate researches of Mitscherlich, the melting point of granite can hardly
exceed 2372 degrees F.
[Dr. Mantell states in 'The Wonders of Geology', 1848, vol. i., p. 34, that
this increase of temperature amounts to 1 degree of Fahrenheit for every
fifty-four feet of vertical depth.] -- Tr.
The quantity of heat peculiar to a planet is, however, a matter of such
importance -- being the result of its primitive condensation, and varying
according to the nature and duration of the radiation -- that the study of
this subject may throw some degree of light on the history of the
atmosphere, and the distribution of the organic bodies imbedded in the solid
crust of the earth. This study enables us to understand how a tropical
temperature, independent of latitude (that is, of the distance from the
poles), may have been produced by deep fissures remaining open, and exhaling
heat from the interior
p 46
of the globe, at a period when the earth's crust was still furrowed and
rent, and only in a state of semi-solidification; and a primordial condition
is thus revealed to us, in which the temperature of the atmosphere, and
climates generally, were owing rather to a liberation of caloric and of
different gaseous emanations (that is to say, rather to the energetic
reaction of the interior on the exterior) than to the position of the earth
with respect to the central body, the sun.
The cold regions of the earth contain, deposited in sedimentary strata, the
products of tropical climates; thus, in the coal formations, we find the
trunks of palms standing upright amid coniferae, tree ferns, goniatites, and
fishes having rhomboidal osseous scales;* in the Jura limestone, colossal
skeletons of crocodiles, plesiosauri, planulites, and stems of the cycadeae;
in the chalk formations, small polythalmia and bryozoa, whose species still
exist in our seas; in tripoli, or polishing slate, in the semi-opal and the
farina-like opal or mountain meal, agglomerations of siliceous infusoria,
which have been brought to light by the powerful microscope of Ehrenberg;**
and, lastly, in transported soils, and in certain caves, the bones of
elephants, hyenas, and lions.
[Footnote] *See the classical work on the fishes of the Old World by
Agassiz, 'Rech. sur les Poissons Fossiles', 1834, vol. i., p. 38; vol. ii.,
p. 3, 28, 34, App., p. 6. The whole genus of Amblypterus, Ag., nearly
allied to Palaeoniscus (called also Palaeothrissum), lies buried beneath the
Jura formations in the old carboniferous strata. Scales which, in some
fishes, as in the family of Lepidoides (order of Ganoides), are formed like
teeth, and covered in certain parts with enamel, belong, after the
Placoides, to the oldest forms of fossil fishes; their living
representatives are still found in two genera, the 'Bichir' of the Nile and
Senegal, and the 'Lepidosteus' of the Ohio.
[Footnote] **[The 'polishing slate' of Bilin is stated by M. Ehrenberg to
form a 'series' of strata fourteen feet in thickness, entirely made up of
the siliceous shells of 'Gaillonellae', of such extreme minuteness that a
cubic inch of the stone contains forty-one thousand millions! The
'Bergmehl' ('mountain meal' or 'fossil farina') of San Fiora, in Tuscany, is
one mass of animalculites. See the interesting work of G. A. Mantell, 'On
the Medals of Creation', vol. i., p. 233.] -- Tr.
An intimate acquaintance with the physical phenomena of the universe leads
us to regard the products of warm latitudes that are thus found in a fossil
condition in northern regions not merely as incentives to barren curiosity,
but as subjects awakening deep reflection, and opening new sources of study.
The number and the variety of the objects I have alluded to give rise to the
question whether general considerations of physical phenomena can be made
sufficiently clear to persons who have not acquired a detailed and special
knowledge of
p 47
descriptive natural history, geology, or mathematical astronomy? I think we
ought to distinguish here between him whose task it is to collect the
individual details of various observations, and study the mutual relations
existing among them, and him to whom these relations are to be revealed,
under the form of general results. The former should be acquainted with the
specialities of phenomena, that he may arrive at a generalization of ideas
as the result, at least in part, of his own observations, experiments, and
calculations. It can not be denied, that where there is an absence of
positive knowledge of physical phenomena, the general results which impart
so great a charm to the study of nature can not all be made equally clear
and intelligible to the reader, but still I venture to hope, that in the
work which I am now preparing on the physical laws of the universe, the
greater part of the facts advanced can be made manifest without the
necessity of appealing to fundamental views and principles. The picture of
nature thus drawn, notwithstanding the want of distinctness of some of its
outlines, will not be the less able to enrich the intellect, enlarge the
sphere of ideas, and nourish and vivify the imagination.
There is, perhaps, some truth in the accusation advanced against many German
scientific works, that they lessen the value of general views by an
accumulation of detail, and do not sufficiently distinguish between those
great results which form, as it were, the beacon lights of science, and the
long series of means by which they have been attained. This method of
treating scientific subjects led the most illustrious of our poets* to
exclaim with impatience, "The Germans have the art of making science
inaccessible." An edifice can not produce a striking effect until the
scaffolding is removed, that had of necessity been used during its erection.
[Footnote] *Gothe, in 'Die Aphorismen uber Naturwissenschaft', bd. I., s.
155 ('Werke kleine Ausgabe','von' 1833.)
Thus the uniformity of figure observed in the distribution of continental
masses, which all terminate toward the south in a pyramidal form, and expand
toward the north (a law that determines the nature of climates, the
direction of currents in the ocean and the atmosphere, and the transition of
certain types of tropical vegetation toward the southern temperate zone),
may be clearly apprehended without any knowledge of the geodesical and
astronomical operations by means of which these pyramidal forms of
continents have been determined. In like manner, physical geography teaches
us by how many leagues
p 48
the equatorial axis exceeds the polar axis of the globe, and shows us the
mean equality of the flattening of the two hemispheres, without entailing on
us the necessity of giving the detail of the measurement of the degrees in
the meridian, or the observations on the pendulum, which have led us to know
that the true figure of our globe is not exactly that of a regular ellipsoid
of revolution, and that this irregularity is reflected in the corresponding
irregularity of the movements of the moon.
The views of comparative geography have been specially enlarged by that
admirable work, 'Erdkunde im VerhÂltniss zur Natur und sur Geschichte', in
which Carl Ritter so ably delineates the physiognomy of our globe, and shows
the influence of its external configuration on the physical phenomena on its
surface, on the migrations, laws, and manners of nations, and on all the
principal historical events enacted upon the face of the earth.
France possesses an immortal work, 'L'Exposition du SystÂme du Monde', in
which the author has combined the results of the highest astronomical and
mathematical labors, and presented them to his readers free from all
processes of demonstration. The structure of the heavens is here reduced to
the simple solution of a great problem in mechanics; yet Laplace's work has
never yet been accused of incompleteness and want of profundity.
The distinction between dissimilar subjects, and the separation of the
general from the special, are not only conducive to the attainment of
perspicuity in the composition of a physical history of the universe, but
are also the means by which a character of greater elevation may be imparted
to the study of nature. By the suppression of all unnecessary detail, the
great masses are better seen, and the reasoning faculty is enabled to grasp
all that might otherwise escape the limited range of the senses.
The exposition of general results has, it must be owned, been singularly
facilitated by the happy revolution experienced since the close of the last
century, in the condition of all the special sciences, more particularly of
geology, chemistry, and descriptive natural history. In proportion as laws
admit of more general application, and as sciences mutually enrich each
other, and by their extension become connected together in more numerous and
more intimate relations, the development of general truths may be given with
conciseness devoid of superficiality. On being first examined, all
phenomena appear to be
p 49
isolated, and it is only by the result of a multiplicity of observations,
combined by reason, that we are able to trace the mutual relations existing
between them. If, however, in the present age, which is so strongly
characterized by a brilliant course of scientific discoveries, we perceive a
want of connection in the phenomena of certain sciences, we may anticipate
the revelation of new facts, whose importance will probably be commensurate
with the attention directed to these branches of study. Expectations of
this nature may be entertained with regard to meteorology, several parts of
optics, and to radiating heat, and electro-magnetism, since the admirable
discoveries of Melloni and Faraday. A fertile field is here opened to
discovery, although the voltaic pile has already taught us the intimate
connection existing between electric, magnetic, and chemical phenomena. Who
will venture to affirm that we have any precise knowledge, in the present
day, of that part of the atmosphere which is not oxygen, or that thousands
of gaseous substances affecting our organs may not be mixed with the
nitrogen, or, finally, that we have even discovered the whole number of the
forces which pervade the universe?
It is not the purpose of this essay on the physical history of the world to
reduce all sensible phenomena to a small number of abstract principles,
based on reason only. The physical history of the universe, whose
exposition I attempt to develop, does not pretend to rise to the perilous
abstractions of a purely rational science of nature, and is simply a
'physical geography, combined with a description of the regions of space and
the bodies occupying them.' Devoid of the profoundness of a purely
speculative philosophy, my essay on the 'Cosmos' treats of the contemplation
of the universe, and is based upon a rational empiricism, that is to say,
upon the results of the facts registered by science, and tested by the
operations of the intellect. It is within these limits alone that the work,
which I now venture to undertake, appertains to the sphere of labor to which
I have devoted myself throughout the course of my long scientific career.
The path of inquiry is not unknown to me, although it may be pursued by
others with greater success. The unity which I seek to attain in the
development of the great phenomena of the universe, is analogous to that
which historical composition is capable of acquiring. All points relating
to the accidental individualities, and the essential variations of the
actual, whether in the form and arrangement of natural objects in the
struggle of man against the elements, or of nations against nations, do not
admit of being
p 50
based only on a 'rational foundation' -- that is to say, of being deduced
from ideas alone.
It seems to me that a like degree of empiricism attaches to the Description
of the Universe and to Civil History; but in reflecting upon physical
phenomena and events, and tracing their causes by the process of reason, we
become more and more convinced of the truth of the ancient doctrine, that
the forces inherent in matter, and those which govern the moral necessity,
and in accordance with movements occurring periodically after longer or
shorter intervals.
It is this necessity, this occult but permanent connection, this periodical
recurrence in the progressive development of forms, phenomena, and events,
which constitute 'nature', obedient to the first impulse imparted to it.
Physics, as the term signifies, is limited to the explanation of the
phenomena of the material world by the properties of matter. The ultimate
object of the experimental sciences is, therefore, to discover laws, and to
trace their progressive generalization. All that exceeds this goes beyond
the province of the physical description of the universe, and appertains to
a range of higher speculative views.
Emmanuel Kant, one of the few philosophers who have escaped the imputation
of impiety, has defined with rare sagacity the limits of physical
explanations, in his celebrated essay 'On the Theory and Structure of the
Heavens', published at Konigsberg in 1755.
The study of a science that promises to lead us through the vast range of
creation may be compared to a journey in a far-distant land. Before we set
forth, we consider, and often with distrust, our own strength, and that of
the guide we have chosen. But the apprehensions which have originated in
the abundance and the difficulties attached to the subjects we would
embrace, recede from view as we remember that with the increase of
observations in the present day there has also arisen a more intimate
knowledge of the connection existing among all phenomena. It has not
unfrequently happened, that the researches made at remote distances have
often and unexpectedly thrown light upon subjects which had long resisted
the attempts made to explain them within the narrow limits of our own sphere
of observation. Organic forms that had long remained isolated, both in the
animal and vegetable kingdom, have been connected by the discovery of
intermediate links or stages of transition. The geography of beings endowed
p 51
with life attains completeness as we see the species, genera, and entire
families belonging to one hemisphere, reflected as it were, in analogous
animal and vegetable forms in the opposite hemisphere. There are, so to
speak, the 'equivalents' which mutually personate and replace one another in
the great series of organisms. These connecting links and stages of
transition may be traced, alternately, in a deficiency or an excess of
development of certain parts, in the mode of junction of distinct organs, in
the differences in the balance of forces, or in a resemblance to
intermediate forms which are not permanent, but merely characteristic of
certain phases of normal development. Passing from the consideration of
beings endowed with life to that of inorganic bodies, we find many striking
illustrations of the high state of advancement to which modern geology has
attained. We thus see, according to the grand views of Elie de Beaumont,
how chains of mountains dividing different climates and floras and different
races of men, reveal to us their 'relative age', both by the character of
the sedimentary strata they have uplifted, and by the directions which they
follow over the long fissures and which the earth's crust is furrowed.
Relations of superposition of trachyte and of syenitic porphyry, of diorite
and of serpentine, which remain in the rich platinum districts of the Oural,
and on the south-western declivity of the Siberian Alti, are elucidated by
the observations that have been made on the plateaux of Mexico and
Antioquia, and in the unhealthy ravines of Choco. The most important facts
on which the physical history of the world has been based in modern times,
have not been accumulated by chance. It has at length been fully
acknowledged, and the conviction is characteristic of the age, that the
narratives of distant travels, too long occupied in the mere recital of
hazardous adventures, can only be made a source of instruction where the
traveler is acquainted with the condition of the science he would enlarge,
and is guided by reason in his researches.
It is by this tendency to generalization, which is only dangerous in its
abuse, that a great portion of the physical knowledge already acquired may
be made the common property of all classes of society; but, in order to
render the instruction impaired by these means commensurate with the
importance of the subject, it is desirable to deviate as widely as possible
from the imperfect compilations designated, till the close of the eighteenth
century, by the inappropriate term of 'popular
p 52
knowledge.' I take pleasure in persuading myself that scientific subjects
may be treated of in language at once dignified, grave, and animated, and
that those who are restricted within the circumscribed limits of ordinary
life, and have long remained strangers to an intimate communion with nature,
may thus have opened to them one of the richest sources of enjoyment, by
which the mind is invigorated by the acquisition of new ideas. Communion
with nature awakens within us perceptive faculties that had long lain
dormant; and we thus comprehend at a single glance the influence exercised
by physical discoveries on the enlargement of the sphere of intellect, and
perceive how a judicious application of mechanics, chemistry, and other
sciences may be made conducive to national prosperity.
A more accurate knowledge of the connection of physical phenomena will also
tend to remove the prevalent error that all branches of natural science are
not equally important in relation to general cultivation and industrial
progress. An arbitrary distinction is frequently made between the various
degrees of importance appertaining to mathematical sciences, to the study of
organized beings, the knowledge of electro-magnetism, and investigations of
the general properties of matter in its different conditions of molecular
aggregation; and it is not uncommon presumptuously to affix a supposed
stigma upon researches of this nature, by terming them "purely theoretical,"
forgetting , although the fact has been long attested, that in the
observation of a phenomenon, which at first sight appears to be wholly
isolated, may be concealed the germ of a great discovery. When Aloysio
Galvani first stimulated the nervous fiber by the accidental contact of two
heterogeneous metals, his contemporaries could never have anticipated that
the action of the voltaic pile would discover to us, in the alkalies, metals
of a silvery luster, so light as to swim on water, and eminently
inflammable; or that it would become a powerful instrument of chemical
analysis, and at the same time a thermoscope and a magnet. When Hygens
first observed, in 1678, the phenomenon of the polarization of light,
exhibited in the difference between the two rays into which a pencil of
light divides itself in passing through a doubly refracting crystal, it
could not have been foreseen that, a century and a half later, the great
philosopher Arago would, by his discovery of 'chromatic polarization', be
led to discern, by means of a small fragment of Iceland spar, whether solar
light emanates from a solid body or a gaseous covering, or
p 53
whether comets transmit light directly or merely by reflection.*
[Footnote] *Arago's Discoveries in the year 1811. -- Delambro's 'Histoire
de l'Ast.', p. 652. (Passage already quoted.)
An equal appreciation of all branches of the mathematical, physical, and
natural sciences is a special requirement of the present age, in which the
material wealth and the growing prosperity of nations are principally based
upon a more enlightened employment of the products and forces of nature.
The most superficial glance at the present condition of Europe shows that a
diminution, or even a total annihilation of national prosperity, must be the
award of those states who shrink with slothful indifference from the great
struggle of rival nations in the career of the industrial arts. It is with
nations as with nature, which, according to a happy expression of GÂthe,*
"knows no pause in progress and development, and attaches her curse on all
inaction."
[Footnote] *Gothe, in 'Die Aphorismen uber Naturwissenschaft.' -- 'Werke',
bd. 1., s. 4
The propagation of an earnest and sound knowledge of science can therefore
alone avert the dangers of which I have spoken. Man can not act upon
nature, or appropriate her forces to his own use, without comprehending
their full extent, and having an intimate acquaintance with the laws of the
physical world. Bacon has said that, in human societies, knowledge is
power. Both must rise and sink together. But the knowledge that results
from the free action of thought is at once the delight and the
indestructible prerogative of man; and in forming part of the wealth of
mankind, it not unfrequently serves as a substitute for the natural riches,
which are but sparingly scattered over the earth. Those states which take
no active part in the general industrial movement, in the choice and
preparation of natural substances, or in the application of mechanics and
chemistry, and among whom this activity is not appreciated by all classes of
society, will infallibly see their prosperity diminish in proportion as
neighboring countries become strengthened and invigorated under the genial
influence of arts and sciences.
As in nobler spheres of thought and sentiment, in philosophy, poetry, and
the fine arts, the object at which we aim ought to be an inward one -- an
ennoblement of the intellect -- so ought we likewise in our pursuit of
science, to strive after a knowledge of the laws and the principles of unity
that pervade the vital forces of the universe; and it is by such a course
that
p 54
physical studies may be made subservient to the progress of industry, which
is a conquest of mind over matter. By a happy connection of causes and
effects, we often see the useful linked to the beautiful and the exalted.
The improvement of agriculture in the hands of freemen, and on properties of
a moderate extent -- the flourishing state of the mechanical arts freed from
the trammels of municipal restrictions -- the increased impetus imparted to
commerce by the multiplied means of the intellectual progress of mankind,
and of the amelioration of political institutions, in which this progress is
reflected. The picture presented by modern history ought to convince those
who are tardy in awakening to the truth of the lesson it teaches.
Nor let it be feared that the marked predilection for the study of nature,
and for industrial progress, which is so characteristic of the present age,
should necessarily have a tendency to retard the noble exertions of the
intellect in the domains of philosophy, classical history, and antiquity, or
to deprive the arts by which life is embellished of the vivifying breath of
imagination. Where all the germs of civilization are developed beneath the
aegis of free institutions and wise legislation, there is no cause for
apprehending that any one branch of knowledge should be cultivated to the
prejudice of others. All afford the state precious fruits, whether they
yield nourishment to man and constitute his physical wealth, or whether,
more permanent in their nature, they transmit in the works of mind the glory
of nations to remotest posterity. The Spartans, notwithstanding their Doric
austerity, prayed the gods to grant them "the beautiful with the good."*
[Footnote] *Pseudo-Plato, -- 'Alcib.', xi., p. 184, ed. Steph.; Plut.,
'Instituta Laconica', p. 253, ed. Hatten.
I will no longer dwell upon the considerations of the influence exercised by
the mathematical and physical sciences on all that appertains to the
material wants of social life, for the vast extent of the course on which I
am entering forbids me to insist further upon the utility of these
applications. Accustomed to distant excursions, I may, perhaps, have erred
in describing the path before us as more smooth and pleasant than it really
is, for such is wont to be the practice of those who delight in guiding
others to the summits of lofty mountains: they praise the view even when
great part of the distant plains lie hidden by clouds, knowing that this
half-transparent vapory vail imparts to the scene a certain charm from
p 55
the power exercised by the imagination over the domain of the senses. In
like manner, from the height occupied by the physical history of the world,
all parts of the horizon will not appear equally clear and well defined.
This indistinctness will not, however, be wholly owing to the present
imperfect state of some of the sciences, but in part, likewise, to the
unskillfulness of the guide who has imprudently ventured to ascend these
lofty summits.
The object of this introductory notice is not, however, solely to draw
attention to the importance and greatness of the physical history of the
universe, for in the present day these are too well understood to be
contested, but likewise to prove how, without detriment to the stability of
special studies, we may be enabled to generalize our ideas by concentrating
them in one common focus, and thus arrive at a point of view from which all
the organisms and forces of nature may be seen as one living active whole,
animated by one sole impulse. "Nature," as Schelling remarks in his poetic
discourse on art, "is not an inert mass; and to him who can comprehend her
vast sublimity, she reveals herself as the creative force of the universe --
before all time, eternal, ever active, she calls to life all things, whether
perishable or imperishable."
By uniting, under one point of view, both the phenomena of our own globe and
those presented in the regions of space, we embrace the limits of the
science of the 'Cosmos', and convert the physical history of the globe into
the physical history of the universe, the one term being modeled upon that
of the other. This science of the Cosmos is not, however, to be regarded as
a mere encyclopedic aggregation of the most important and general results
that have been collected together from special branches of knowledge. These
results are nothing more than the materials for a vast edifice, and their
combination can not constitute the physical history of the world, whose
exalted part it is to show the simultaneous action and the connecting links
of the forces which pervade the universe. The distribution of organic types
in different climates and at different elevations -- that is to say, the
geography of plants and animals -- differs as widely from botany and
descriptive zoology as geology does from mineralogy, properly so called.
The physical history of the universe must not, therefore, be confounded with
the 'Encyclopedias of the Natural Sciences', as they have hitherto been
compiled, and whose title is as vague as their limits are ill defined. In
the work before us, partial facts will be considered only in relation to the
whole.
p 56
The higher the point of view, the greater is the necessity for a systematic
mode of treating the subject in language at once animated and picturesque.
But thought and language have ever been most intimately allied. If
language, by its originality of structure and its native richness, can, in
its delineations, interpret thought with grace and clearness, and if, by its
happy flexibility, it can paint with vivid truthfulness the objects of the
external world, it reacts at the same time upon thought, and animates it, as
it were, with the breath of life. It is this mutual reaction which makes
words more than mere signs and forms of thought; and the beneficent
influence of a language is most strikingly manifested on its native soil,
where it has sprung spontaneously from the minds of the people, whose
character it embodies. Proud of a country that seeks to concentrate her
strength in intellectual unity, the writer recalls with delight the
advantages he has enjoyed in being permitted to express his thoughts in his
native language; and truly happy is he who, in attempting to give a lucid
exposition of the great phenomena of the universe, is able to draw from the
depths of a language, which, through the free exercise of thought, and by
the effusions of creative fancy, has for centuries past exercised so
powerful an influence over the destinies of man.
This material taken from pages 56 to 78
COSMOS: A Sketch of the Physical Description of the Universe, Vol. 1
by Alexander von Humboldt
Translated by E C Otte
from the 1858 Harper & Brothers edition of Cosmos, volume 1
--------------------------------------------------
p 56
LIMITS AND METHOD OF EXPOSITION OF THE PHYSICAL DESCRIPTION OF THE UNIVERSE.
I HAVE endeavored, in the preceding part of my work, to explain and
illustrate, by various examples, how the enjoyments presented by the aspect
of nature, varying as they do in the sources from when they flow, may be
multiplied and ennobled by an acquaintance with the connection of phenomena
and the laws by which they are regulated. It remains, then, for me to
examine the spirit of the method in which the exposition of the 'physical
description of the universe' should be conducted, and to indicate the limits
of this science in accordance with the views I have acquired in the course
of my studies and travels in various parts of the earth. I trust I may
flatter myself with a hope that a treatise of this nature will justify the
title I have ventured to adopt for my work, and exonerate me from the
reproach of a presumption that would be doubly reprehensible in a scientific
discussion.
Before entering upon the delineation of the partial phenomena
p 57
which are found to be distributed in various groups, I would consider a few
general questions intimately connected together, and bearing upon the nature
of our knowledge of the external world and its different relations, in all
epochs of history and in all phases of intellectual advancement. Under this
head will be comprised the following considerations:
1. The precise limits of the physical description of the universe,
considered as a distinct science.
2. A brief enumeration of the totality of natural phenomena, presented
under the form of a 'general delineation of nature.'
3. The influence of the external world on the imagination and feelings,
which has acted in modern times as a powerful impulse toward the study of
natural science, by giving animation to the description of distant regions
and to the delineation of natural scenery, as far as it is characterized by
vegetable physiognomy and by the cultivation of exotic plants, and their
arrangement in well-contrasted groups.
4. The history of the contemplation of nature, or the progressive
development of the idea of the Cosmos, considered with reference to the
historical and geographical facts that have led to the discovery of the
connection of phenomena.
The higher the point of view from which natural phenomena may be considered,
the more necessary it is to circumscribe the science within its just limits,
and to distinguish it from all other analogous or auxiliary studies.
Physical cosmography is founded on the contemplation of all created things
-- all that exists in space, whether as substances or forces -- that is, all
the material beings that constitute the universe. The science which I would
attempt to define presents itself, therefore, to man, as the inhabitant of
the earth, under a two-fold form -- as the earth itself and the regions of
space. It is with a view of showing the actual character and the
independence of the study of physical cosmography, and at the same time
indicating the nature of its relations to 'general physics, descriptive
natural history, geology, and comparative geography', that I will pause for
a few moments to consider that portion of the science of the Cosmos which
concerns the earth. As the history of philosophy does not consist of a mere
material enumeration of the philosophical views entertained in different
ages, neither should the physical description of the universe be a simple
encyclopedic compilation of the sciences we have enumerated. The difficulty
of defining the limits of intimately-connected studies has been increased,
because for centuries it has been customary to designate various branches
p 58
of empirical knowledge by terms which admit either of too wide or too
limited a definition of the ideas which they were intended to convey, and
are, besides, objectionable from having had a different signification in
those classical languages of antiquity from thish chey have been borrowed.
The terms physiology, physics, natural history, geology and geography arose,
and were commonly used, long before clear ideas were entertained of the
diversity of objects embraced by these sciences, and consequently of their
reciprocal limitation. Such is the influence of long habit upon language,
that by one of the nations of Europe most advanced in civilization the word
"physic" is applied to medicine, while in a society of justly deserved
universal reputation, technical chemistry, geology and astronomy (purely
experimental sciences) are comprised under the head of "Philosophical
Transactions."
An attempt has often been made, and almost always in vain, to substitute new
and more appropriate terms for these ancient designations, which,
notwithstanding their undoubted vagueness, are now generally understood.
These changes have been proposed, for the most part, by those who have
occupied themselves with the general classification of the various branches
of knowledge, from the first appearance of the great encyclopedia
('Margarita Philosophica') of Gregory Reisch,* prior of the Chartreuse at
Freiburg, toward the close of the fifteenth century, to Lord Bacon, and from
Bacon to D'Alembert; and in recent times to an eminent physicist, Andre
Marie Ampere.**
[footnote] *The 'Margarita Philosophica' of Gregory Reisch, prior of the
Chartreuse at Freiburg, first appeared under the following title: Aepitome
omnis Philosophi¾, alias Margarita Philosophica, tractans de omni generi
scibili. The Heidelberg edition (1486), and that of Strasburg (1504), both
bear this title, but the first part was suppressed in the Freiburg edition
of the same year, as well as in the twelve subsequent editions, which
succeeded one another, at short intervals, till 1535. This work exercised a
great influence on the diffusion of mathematical and physical sciences
toward the beginning of the sixteenth century, and Crasles, the learned
author of 'L'AperÂu Historique des Methodes en GÂometrica' (1837) has
shown the great importance of Reisch's 'Encyclopedia' in the history of
mathematics in the Middle Ages. I have had recourse to a passage in the
'Margarita Philosophica', found only in the edition of 1513, to elucidate
the important question of the relations between the statements of the
geographer of Saint-Die, Hylacomilus (Martin Waldseemuller), the first who
gave the name of America to the New Continent, and those of Amerigo
Vespucci, Rene, King of Jerusalem and Duke of Lorraine, as also those
contained in the celebrated editions of Ptolemy of 1513 and 1522. See my
'Examen Critique de la Gegraphie du Nouveau Continent, et des Progres de
l'Astronomie Nautique aux 15e et 16e Siecles', t. iv., p. 99-125.
[footnote] II AmpÂre, 'Essai sur la Phil. des Sciences', 1834, p. 25.
Whewell, 'Philosophy of the Inductive Sciences', vol. ii., p. 277. Park,
'Pantology', p. 87.
p 59
The selection of an inappropriate Greek nomenclature has perhaps been even
more prejudicial to the last of these attempts than the injudicious use of
binary divisions and the excessive multiplication of groups.
The physical description of the world, considering the universe as an object
of the external senses, does undoubtedly require the aid of general physics
and of descriptive natural history, but thecontemplation of all created
things, which are linked together, and form one 'whole', animated by
internal forces, given to the science we are considering a peculiar
character. Phyical science considers only the general properties of bodies;
it is the product of abstraction -- a generalization of perceptible
phenomena; and even in the work in which were laid the first foundations of
general physics, in the eight books on physics of Aristotle,* all the
phenomena of nature are considered as depending upon the primitive and vital
action of one sole force, from which emaate all the movements of the
universe.
[footnote] * All changes in the physical world may be reduced to motion.
Aristot., 'Phys. Ausc.', iii., 1 and 4, p. 200, 201. Bekker, viii., 1, 8,
and 9, p. 250, 262, 265. 'De Genere et Corr.', ii., 10, p. 336.
Pseudo-Aristot., 'De Mundo.' cap. vi., p. 398.
The terrestrial portion of physical cosmography, for which I would willingly
retain the expressive designation of 'physical geography', treats of the
distribution of magnetism in our planet with relation to its intensity and
direction, but does not enter into a consideration of the laws of attraction
or repulsion of the poles, or the means of eliciting either permanent or
transitory electro-magnetic currents. Physical geography depicts in broad
outlines the even or irregular configuration of continents, the relations of
superficial area, and the distribution of continental masses in the two
hemispheres, a distribution which exercises a powerful influence on the
diversity of climate and the meteorological modifications of the atmosphere;
this science defines the character of mountain chains, which, having been
elevated at different epochs, constitute distinct systems, whether they run
in parallel lines or intersect one another; determines the mean height of
continents above the level of the sea, the position of the center of gravity
of their volume, and the relation of the highest summits of mountain chains
to the mean elevation of their crests, or to their proximity with the
sea-shore. It depicts the eruptive rocks as principles of movement, acting
upon the sedimentary rocks by traversing, uplifting, and inclining them at
various angles; it
p 60
considers volcanoes either as isolated, or ranged in single or in double
series, and extending their sphere of action to various distances, either by
raising long and narrow lines of rocks, or by means of circles of commotion,
which expand or diminish in diameter in the course of ages. This
terrestrial portion of the science of the Cosmos describes the strife of the
liquid element with the solid land; it indicates the features possessed in
common by all great rivers in the upper and lower portion of their course,
and in their mode of bifurcation when their basins are unclosed; and shows
us rivers breaking through the highest mountain chains, or following for a
long time a course parallel to them, either at their base, or at a
considerable distance, where the elevation of the strata of the mountain
system and the direction of their inclination correspond to the
configuration of the table-land. It is only the general results of
comparative orography and hydrography that belong to the science whose true
limits I am desirous of determining, and not the special enumeration of the
greatest elevations of our globe, of active volcanoes, of rivers, and the
number of their tributaries, these details falliing rather within the domain
of geography, properly so called. We would here only consider phenomena in
their mutual connection, and in their relations to different zones of our
planet, and to its physical constitution generally. The specialties both of
inorganic and organized matter, classed according to analogy of form and
composition, undoubtedly constitute a most interesting branch of study, but
they appertain to a sphere of ideas having no affinity with the subject of
this work.
The description of different countries certainly furnishes us with the most
important materials for the composition of a physical geography; but the
combination of these different descriptions, ranged in series, would as
little give us a true image of the general conformation of the irregular
surface of our globe, as a succession of all the floras of different regions
would constitute that which I designate as a 'Geography of Plants.' It is
by subjecting isolated observations to the process of thought, and by
combining and comparing them, that we are enabled to discover the relations
existing in common between the climatic distribution of beings and the
individuality of organic forms (in the morphology or descriptive natural
history of plants and animals); and it is by induction that we are led to
comprehend numerical laws, the proportion of natural families to the whole
number of species, and to designate the latitude or geographical position of
the zones in whose
p 61
plains each organic form attains the maximum of its development.
Considerations of this nature, by their tendency to generalization, impress
a nobler character on the physical description of the globe, and enable us
to understand how the aspect of the scenery, that is to say, the impression
produced upon the mind by the physiognomy of the vegetation, depends upon
the local distribution, the number, and the luxuriance of growth of the
vegetable forms predominating in the general mass. The catalogues of
organized beings to which was formerly given the pompous title of 'Systems
of Nature', present us with an admirably connected arrangement by analogies
of structure, either in the perfected development of these beings, or in the
different phases which, in accordance with the views of a spiral evolution,
affect in vegetables the leaves, bracts, calyx, corolla and fructifying
organs; and in animals, with more or less symmetrical regularity, the
cellular and fibrous tissues, and their perfect or but obscurely developed
articulations. But these pretended systems of nature, however ingenious
their mode of classification may be, do not show us organic beings as they
are distributed in groups throughout our planet, according to their
different relations of latitude and elevation above the level of the sea,
and to climatic influences, which are owing to general and often very remote
causes. The ultimate aim of physical geography is, however, as we have
already said, to recognise unity in the vast diversity of phenomena, and by
the exercise of thought and the combination of observations, to discern the
constancy of phenomena in the midst of apparent changes. In the exposition
of the terrestrial portion of the Cosmos, it will occasionally be necessary
to descend to very special facts; but this will only be in order to recall
the connection existing between the actual distribution of organic beings
over the globe, and the laws of the ideal classification by natural
families, analogy of internal organization and progressive evolution.
It follows from these discussions on the limits of the various sciences, and
more particularly from the distinction which must necessarily be made
between descriptive botany (morphology of vegetables) and the geography of
plants, that in the physical history of the globe, the innumerable multitude
of organized bodies which embellish creation are considered rather according
to 'zones of habitation' or 'stations', and to differently inflected
'isothermal bands', than with reference to the principles of gradation in
the development of internal organism. Notwithstanding this, botany and
zoology, which constitute
p 62
the descriptive natural history of all organized beings, are the fruitful
sources whence we draw the materials necessary to give a solid basis to the
study of the mutual relations and connection of phenomena.
We will here subjoin one important observation by way of elucidating the
connection of which we have spoken. The first general glance over the
vegetation of a vast extent of a continent shows us forms the most
dissimilar -- Graminae and Orchideae, Coniferae and oaks, in local
approximation to one another; while natural families and genera, instead of
being locally associated, are dispersed as if by chance. This dispersion
is, however, only apparent. The physical description of the globe teaches
us that vegetation every where presents numerically constant relations in
the development of its forms and types; that in the same climates, the
species which are wanting in one country are replaced in a neighboring one
by other species of the same family; and that this 'law of substitution',
which seems to depend upon some inherent mysteries of the organism,
considered with reference to its origin, maintains in contiguous regions a
numerical relation between the species of various great families and the
general mass of the phanerogamic plants constituting the two floras. We
thus revealed in the multiplicity of the distinct organizations by which
these regions are occupied; and we also discover in each zone, and
diversified according to the families of plants, a slow but continuous
action on the aerial ocean, depending upon the influence of light -- the
primary condition of all organic vitality -- on the solid and liquid surface
of our planet. It might be said, in accordance with a beautiful expression
of Lavoisier, that the ancient marvel of the myth of Prometheus was
incessantly renewed before our eyes.
If we extend the course which we have proposed, following in the exposition
of the physical description of the earth to the sidereal part of the science
of the Cosmos, the delineation of the regions of space and the bodies by
which they are occupied, we shall find our task simplified in no common
degree. If, according to ancient but unphilosophical forms of nomenclature,
we would distinguish between 'physics', that is to say, general
considerations on the essence of matter, and the forces by which it is
actuated, and 'chemistry', which treats of the nature of substances, their
elementary composition, and those attractions that are not determined solely
by the relations of mass, we must admit that the description of the earth
comprises at
p 63
once 'physical' and 'chemical' actions. In addition to gravitation, which
must be considered as a primitive force in nature, we observe that
attractions of another kind are at work around us, both in the interior of
our planet and on its surface. These forces, to which we apply the term
'chemical affinity', act upon molecules in contact, or at infinitely minute
distances from one another,* and which, being differently modified by
electricity, heat, condensation in porous bodies, or by the contact of an
intermediate substance, animate equally the inorganic world and animal and
vegetable tissues.
[footnote] * On the question already discussed by Newton, regarding the
difference existing between the attraction of masses and molecular
attraction, see Laplace, 'Exposition du Systeme du Monde', p. 384, and
supplement to book x. of the 'Mecanique Celeste', p. 3, 4; Kant, 'Metaph.
Anfangegrunde der Naturwissenschaft, SÂm. Werke', 1839, bd. v., s. 309
(Metaphysical Principles of the Natural Sciences); Pectet, 'Physique', 1838,
vol. i., p. 59-63.
If we except the small asteroids, which appear to us under the forms of
aerolites and shooting stars, the regions of space have hitherto presented
to our direct observation physical phenomena alone; and in the case of
these, we know only with certainty the effects depending upon the
quantitative relations of matter of the distribution of masses. The
phenomena of the regions of space may consequently be considered as
influenced by simple dynamical laws -- the laws of motion.
The effects that may arise from the specific difference and the
hererogeneous nature of matter have not hitherto entered into our
calculations of the mechanism of the heavens. The only means by which the
inhabitants of our planet can enter into relation with the matter contained
within the regions of space, whether existing in scattered forms or united
into large spheroids, is by the phenomena of light, the propagation of the
force of gravitation or the attraction of masses. The existence of a
periodical action of the sun and moon on the variations of terrestrial
magnetism is even at the present day extremely problematical. We have no
direct experimental knowledge regarding the properties and specific
qualities of the masses circulating in space, or of the matter of which they
are probably composed, if we except what may be derived from the fall of
aerolites or meteoric stones, which, as we have already observed, enter
within the limits of our terrestrial sphere. It will be sufficient here to
remark, that the direction and the excessive velocity of projection (a
velocity wholly planetary) manifested by these masses, render it more than
probable that
p 64
they are small celestial bodies, which, being attracted by our planet, are
made to deviate from their original course, and thus reach the earth
enveloped in vapors, and in a high state of actual incandescence. The
familiar aspect of these asteroids, and the analogies which they present
with the minerals composing the earth's crust, undoubtedly afford ample
grounds for surprise,* but, in my opinion, the only conclusion to be drawn
from these facts is that, in general, planets and other sidereal masses,
which by the influence of a central body, have been agglomerated into rings
of vapor, and subsequently into spheroids, being integrant parts of the same
system, and having one common origin, may likewise be composed of substances
chemically identical.
[footnote] I[The analysis of an aerolite which fell a few years since in
Maryland, United States, and was examined by Professor Silliman, of New
Haven, Connecticut, gave the following results: Oxyd of iron, 24; oxyd of
nickel, 1.25; silica, with earthy matter, 3.46; sulphur, a trace - 28.71.
Dr. Mantell's 'Wonders of Geology', 1848, vol. i., p. 51.] -- 'Tr.'
Again, experiments with the pendulum, particularly those prosecuted with
such rare precision by Bessel, confirm the Newtonian axiom, that bodies the
most heterogeneous in their nature (as water, gold, quartz, granular
limestone, and different masses of aerolites) experience a perfectly similar
degree of acceleration from the attraction of the earth. To the experiments
of the pendulum may be added the proofs furnished by purely astronomical
observations. The almost perfect identity of the mass of Jupiter, deduced
from the influence exercised by this stupendous planet on its own
satellites, on Enck's comet of short period, and on the small planets Vesta,
Juno, Ceres, and Pallas, indicates with equal certainty that within the
limits of actual observation attraction is determined solely by the quantity
of matter.*
[footnote] *Poisson, 'Connaissances des Temps pour l'Anne' 1836, p. 64-66.
Bessel, Poggendorf's 'Annalen', bd. xxv., s. 417. Encke, 'Abhandlungen der
Berliner Academie' (Trans. of the Berlin Academy), 1826, s. 257.
Mitscherlich, 'Lehrbuch der Chemie' (Manual of Chemistry), 1837 bd. i. s.
352.
This absence of any perceptible difference in the nature of matter, alike
proved by direct observation and theoretical deductions, imparts a high
degree of simplicity to the mechanism of the heavens. The immeasurable
extent of the regions of space being subjected to laws of motion alone, the
sidereal portion of the science of the Cosmos is based on the pure and
abundant source of mathematical astronomy, as is the terrestrial portion on
physics, chemistry, and organic morphology; but the domain of these three
last-named sciences embraces
p 65
the consideration of phenomena which are so complicated and have, up to the
present time, been found so little susceptible of the application of
rigorous method, that the physical science of the earth can not boast of the
same certainty and simplicity in the exposition of facts and their mutual
connection which characterize the celestial portion of the Cosmos. It is
not improbable that the difference to which we allude may furnish an
explanation of the cause which, in the earliest ages of intellectual culture
among the Greeks, directed the natural philosophy of the Pythagoreans with
more ardor to the heavenly bodies and the regions of space than to the earth
and its productions, and how through Philolaus, and subsequently through the
analogous views of Aristarchus of Samos, and of Seleucus of Erythrea, this
science has been made more conducive to the attainment of a knowledge of the
true system of the world than the natural philosophy of the Ionian school
could ever be to the physical history of the earth. Giving but little
attention to the properties and specific differences of matter filling
space, the great Italian school, in its Doric gravity, turned by preference
toward all that relates to measure, to the form of bodies, and to the number
and distances of the planets,* while the Ionian physicists directed their
attention to the qualities of matter, its true or supposed metamorphoses,
and to relations of origin.
[footnote] *Compare Otfried Muller's 'Dorien', bd. i., s. 365.
It was reserved for the powerful genius of Aristotle, alike profoundly
speculative and practical to sound with equal success the depths of
abstraction and the inexhaustible resources of vital activity pervading the
material world.
Several highly distinguished treatises on physical geography are prefaced by
an introduction, whose purely astronomical sections are directed to the
consideration of the earth in its planetary dependence, and as constituting
a part of that great system which is animated by one central body, the sun.
This course is diametrically opposed to the one which I propose following.
In order adequately to estimate the dignity of the Cosmos, it is requisite
that the sidereal portion, termed by Kant the 'natural history of the
heavens', should not be made subordinate to the terrestrial. In the science
of the Cosmos, according to the expression of Aristarchus of Samos, the
pioneer of the Copernican system, the sun, with its satellites, was nothing
more than one of the innumerable stars by which space is occupied. The
physical history of the world must, therefore, begin with the description of
the heavenly bodies,
p 66
and with a geographical sketch of the universe, or, I would rather say, a
true 'map of th world', such as was traced by the bold hand of the elder
Herschel. If, notwithstanding the smallness of our planet, the most
considerable space and the most attentive consideration be here afforded to
that which exclusively concerns it, this arises solely from the
disproportion in the extent of our knowledge of that which is accessible and
of that which is closed to our observation. This subordination of the
celestial to the terrestrial portion is met with in the great work of
Bernard Varenius,* which appeared in the middle of the seventeenth century.
[Footnote] *'Geographia Generalis in qua affectiones generales telluris
explicantur.' The oldest Elzevir edition bears date 1650, the second 1672,
and the third 1681; these were published at Cambridge, under Newton's
supervision. This excellent work by Varenius is, in the true sense of the
words, a physical description of the earth. Since the work 'Historia
Natural de las Indias', 1590, in which the Jesuit Joseph de Acosta sketched
in so masterly a manner the delineation of the New Continent, questions
relating to the physical history of the earth have never been considered
with such admirable generality. Acosta is richer in original observations,
while Varenius embraces a wider circle of ideas, since his sojourn in
Holland, which was at that period the center of vast commercial relations,
had brought him in contact with a great number of well-iinformed travelers.
'Generalis sive Universalis Geographia dictur quae tellurem in genere
considerat atque affectiones explicat, non habita particularium regionum
ratione.' The general description of the earth by Varenius ('Pars
Absoluta', cap. i.-xxii.) may be considered as a treatise of comparative
geography, if we adopt the term used by the author himself ('Geographia
Comparativa', cap. xxxiii.-xl.), although this must be understood in a
limited acceptation. We may cite the following among the most remarkable
passages of this book: the enumeration of the systems of mountains; the
examination of the relations existing between their directions and the
general form of continents (p. 66, 76, ed. Cantab., 1681); a list of extinct
volcanoes, and such as were still in a state of activity; the discussion of
facts relative to the general distribution of islands and archipelagoes (p.
220); the depth of the ocean relatively to the height of neighboring coasts
(p. 103); the uniformity of level observed in all open seas (p. 97); the
dependence of currents on the prevailing winds; the unequal saltness of the
sea; the configuration of shores (p. 139); the direction of the winds as the
result of differences of temperature, etc. We may further instance the
remarkable considerations of Varenius regarding the equinoctial current from
east to west, to which he attributes the origin of the Gulf Stream,
beginning at Cape St. Augustin, and issuing forth between Cuba and Florida
(p. 140). Nothing can be more accurate than his description of the current
which skirts the western coast of Africa, between Cape Verde and the island
of Fernando Po in the Gulf of Guinea. Varenius explains the formation of
sporadic islands by supposing them to be "the raised bottom of the sea:"
'magna spirituum inclusorum vi, sicut aliquando montes e terra protusos esse
quidam scribunt' (p. 225). The edition published by Newton in 1681
('auctior et emendatior' unfortunately contains no additions from this great
authority; and there is not even mention made of the polar compression of
the globe, although the experiments on the pendulum by Richer had been made
nine years prior to the appearance of the Cambridge edition. Newton's
'Principia Mathematica Philosophie Naturalis' were not communicated in
manuscript to the Royal Society until April, 1686. Much uncertainty seems
to prevail regarding the birth-place of Varenius. Jaecher says it was
England, while, according to 'La Biographie Universelle' (b.xlvii., p. 495),
he is stated to have been born at Amsterdam; but it would appear, from the
dedicatory address to the burgomaster of that city (see his 'Geographia
Comparativa', that both suppositions are false. Varenius expressly says
that he had sought refuge in Amsterdam, "because his native city had been
burned and completely destroyed during a long war," words which appear to
apply to the north of Germany, and to the devastations of the Thirty Years'
War. In his dedication of another work, 'Descriptio regni Japoniae' (Amst.,
1649), to the Senate of Hamburgh, Varenius says that he prosecuted his
elementary mathematical studies in the gymnasium of that city. There is,
therefore, every reason to believe that this admirable geographer was a
native of Germany, and was probably born at Luneburg ('Witten. Mem. Theol.',
1685, p. 2142; Zedler, 'Universal Lexicon', vol. xlvi., 1745, p. 187).
p 67
He was the first to distinguish between 'general and special geography', the
former of which he subdivides into an 'absolute', or, properly speaking,
'terrestrial' part, and a 'relative or planetary' portion, according to the
mode of considering our planet either with reference to its surface in its
different zones, or to its relations to the sun and moon. It redounds to
the glory of Varenius that his work on 'General and Comparative Geography'
should in so high a degree have arrested the attention of Newton. The
imperfect state of many of the auxiliary sciences from which this writer was
obliged to draw his materials prevented his work from corresponding to the
greatness of the design, and it was reserved for the present age, and for my
own country, to see the delineation of comparative geography, drawn in its
full extent, and in all its relations with the history of man, by the
skillful hand of Carl Ritter.*
[Footnote] *Carl Ritter's 'Erdkunde im VerhÂltniss zur Natur und zur
Geschichte des Menschen, oder allgemeine vergleichende Geographie'
(Geography in relation to Nature and the History of Man, or general
Comparative Geography).
The enumeration of the most important results of the astronomical and
physical sciences which in the history of the Cosmos radiate toward one
common focus, may perhaps, to a certain degree, justify the designation I
have given to my work, and, considered within the circumscribed limits I
have proposed to myself, the undertaking may be esteemed less adventurous
than the title. The introduction of new terms, especially with reference to
the general results of a science which
p 68
ought to be accessible to all, has always been greatly in opposition to my
own practice; and whenever I have enlarged upon the established
nomenclature, it has only been in the specialities of descriptive botany and
zoology, where the introduction of hitherto unknown objects rendered new
names necessary. The denominations of physical descriptions of the
universe, or physical cosmography, which I use indiscriminantely, have been
modeled upon those of 'physical descriptions of the earth', that is to say,
'physical geography', terms that have long been in common use. Descartes,
whose genius was one of the most powerful manifested in any age, has left us
a few fragments of a great work, which he intended publishing under the
title of 'Monde', and for which he had prepared hiimself by special studies,
including even that of human anatomy. The uncommon, but definite expression
of the 'science of the Cosmos' recalls to the mind of the inhabitant of the
earth that we are treating of a more widely-extended horizon -- of the
assemblage of all things with which space is filled, from the remotest
nebulae to the climatic distribution of those delicate tissues of vegetable
matter which spread a variegated covering over the surface of our rocks.
The influence of narrow-minded views peculiar to the earlier ages of
civilization led in all languages to a confusion of ideas in the synonymic
use of the words 'earth' and 'world', while the common expressions 'voyages
round the world', 'map of the world', and 'new world', afford further
illustrations of the same confusion. The more noble and precisely-defined
expressions of 'system of the world', 'the planetary world', and 'creation
and age of the world', relate either to the totality of the substances by
which space is filled, or to the origin of the whole universe.
It was natural that, in the midst of the extreme variability of phenomena
presented by the surface of our globe, and the aerial ocean by which it is
surrounded, man should have been impressed by the aspect of the vault of
heaven, and the uniform and regular movements of the sun and planets. Thus
the word Cosmos, which primitively, in the Homeric ages, indicated an idea
of order and harmony, was subsequently adopted in scientific language, where
it was gradually applied to the order observed in the movements of the
heavenly bodies, to the whole universe, and then finally to the world in
which this harmony was reflected to us. According to the assertion of
Philolaus, whose fragmentary works have been so ably commented upon by
BÂckh, and conformably to the general testimony
p 69
of antiquity, Pythagoras was the first who used the word Cosmos to designate
the order that reigns in the universe, or entire world.*
[footnote] *[Greek word], in the most ancient, and at the same time most
precise, definition of the word, signified 'ornament' (as an adornment for a
man, a woman, or a horse); taken figuratively for [Greek word], it implied
the order or adornment of a discourse. According to the testimony of all
the ancients, it was Pythagoras who first used the word to designate the
order in the universe, and the universe itself. Pythagoras left no
writings; but ancient attestation to the truth of this assertion is to be
found in several passages of the fragmentary works of Philolaus (Stob.,
'Eclog.', p. 360 and 460, Heeren), p. 62, 90, in Bockh's German edition. I
do not, according to the example of Nake, cite Timof Locris, since his
authenticity is doubtful. Plutarch ('De plac. Phil.', ii., I) says, in the
most express manner, that Pythatoras gave the name of Cosmos to the universe
on account of the order which reigned throughout it; so likewise does Galen
('Hist. Phil.', p. 429). This word, together with its novel signification,
passed from the schools of philosophy into the language of poets and prose
writers. Plato designates the heavenly bodies by the name of 'Uranos', but
the order pervading the regions of space he too terms the Cosmos, and in his
'Timus' (p. 30 a.) he says 'that the world is an animal endowed with a soul'
[Greek words]. Compare Anaxag. Claz., ed. Schaubach, p. III, and Plut.
('De plac. Phil.', in Aristotle ('De Caelo', I, 9), 'Cosmos' signifies "the
universe and the order pervading it," but it is likewise considered as
divided in space into two parts -- the sublunary world, and the world above
the moon. ('Meteor.', I., w, 1, and I., 3, 13, p. 339, 'a', and 340, 'b',
Bekk.) The definition of Cosmos, which I have already cited is taken from
Pseudo-Aristoteles 'de Mundo', cap. ii. (p. 391); the passage referred to is
as follows: [Greek words]. Most of the passages occurring in Greek writers
on the word 'Cosmos' may be found collected together in the controversy
between Richard Bentley and Charles Boyle ('Opuscula Philologica', 1781, p.
347, 445; 'Dissertation upon the Epistles of Phalaris', 1817, p. 254); on
the historical existence of Zaleucus, legislator of Leucris, in Nake's
excellent work, 'Sched. Crit.', 1812, p. 9, 15; and, finally in Theophilus
Schmidt, 'ad Cleom. Cycl. Theor.', met. I., 1, p. ix., 1 and 99. Taken in a
more limited sense, the word Cosmos is also used in the plural (Plut., 1,
5), either to designate the stars (Stob., 1, p. 514; Plut., 11, 13) or the
innumerable systems scattered like islands through the immensity of space,
and each composed of a sun and a moon. (Anax. Claz., 'Fragm.', p. 89, 93,
120; Brandis, 'Gesch. der Griechisch-RÂmischen Philosophie', b. i., s. 252
(History of the Greco-Roman Philosophy). Each of these groups forming thus
a 'Cosmos', the universe, [Greek words], the word must be understood in a
wider sense (Plut., ii., 1). It was not until long after the time of the
Ptolemies that the word was applied to the earth. Bockh has made known
inscriptions in praise of Trajan and Adrian ('Corpus Inscr. Graec.', I, n.
334 and 1036), in which [Greek word] occurs for [Greek word] in the same
manner as we still use the term 'world' to signify the earth alone. We have
already mentioned the singular division of the regions of space
p 70 [Footnote continues]
into three parts, the 'Olympus, Cosmos' and 'Ouranos' (Stob., i., p. 488;
Philolaus, p. 95, 303); this division applies to the different regions
surrounding that mysterious focus of the universe, the [Greek words] of the
Pythagoreans. In the fragmentary passage in which this division is found,
the term [Greek word] designates the innermost region, situated between the
moon and earth; this is the domain of changing things. The middle region,
where the planets circulate in an invariable and harmonious order, is, in
accordance with the special conceptions entertained of the universe,
exclusively termed 'Cosmos', while the word 'Olympus' is used to express the
exterior or igneous region. Bopp, the profound philologist, has remarked
that we may deduce, as Pott has done, 'Etymol. Forschungen', th.i., s. 39
and 252 ('Etymol. Researches'), the word [Greek word] from the Sanscrit
root 'sud', 'purificari', by assuming two conditions; first that the Greek
letter 'kappa' in [Greek word] comes from the palatial 'epsilon', which Bopp
represents by 's' and Pott by 'Â' (in the same manner as [Greek word],
'decem, taihun' in Gothic, comes from the Indian word 'dasan'), and, next,
that the Indian 'd'' corresponds, as a general rule, with the Greek 'theta'
('Vergleichende Grammatik' 99 -- Comparative Grammar), which shows the
relation of [Greek word] (for [Greek word]) with the Sanscrit root 'sud',
whence is also derived [Greek word]. Another Indian term for the world is
'gagat' (pronounced 'dschagat'), which is, properly speaking the present
participle of the verb 'gagami' (I go), the root of which is 'ga.' In
restricting ourselves to the circle of Hellenic etymologies, we find
('Etymol. M.', p. 532, 12) that [Greek word] is intimately associated with
[Greek word] or rather with [Greek word], whence we have [Greek word] or
[Greek word] Welcker ('Eine Kretische Col in Theben', s. 23 -- A Cretan
Colony in Thebes) combines with this the name [Greek word] , as in Hesychius
[Greek word] signifies a Cretan suit of arms. When the scientific language
of Greece was introduced among the Romans, the word 'mundus', which at first
had only the primary meaning of [Greek word] (female ornament), was applied
to designate the entire universe. Ennius seems to have been the first who
ventured upon this innovation. In one of the fragments of this poet,
preserved by Macrobius, on the occasion of his quarrel with Virgil, we find
the word used in its novel mode of acceptation: "Mundus caeli vastus
constitit silentio" (Sat., vi., 2). Cicero also says, "Quem nos lucentem
mundum vocamus" (Tim¾us, 'S.de univer.', cap. x.) The Sanscrit root 'mand'
from which Pott derives the Latin 'mundus' ('Etym. Forsch.', th. i., s.
240), combines the double signification of shining and adorning. 'Loka'
designates in Sanscrit the world and people in general, in the same manner
as the French word 'monde', and is derived according to Bopp, from 'lok' (to
see and shine); it is the same with the Slavonic root 'swjet', which means
both 'light' and 'world.' (Grimm, 'Deutsche Gramm.', b. iii., s. 394 --
German Grammar.) The word 'welt', which the Germans make use of at the
present day, and which was 'weralt' in old German, 'worold' in old Saxon,
and 'weruld' in Anglo-Saxon, was, according to James Grimm's interpretation,
a period of time, an age ('saeculum') rather than a term used for the world
in space. The Etruscans figured to themselves 'mundus' as an inverted dome,
symmetrically opposed to the celestial vault (Otfried Muller's 'Etrusken',
th. ii., s. 96, etc.). Taken in a still more limited sense, the word
appears to have signified among the Goths the terrestrial surface girded by
seas ('marei, meri',) the 'merigard', literally, 'garden of seas.'
From the Italian school of philosophy, the expression passed, in this
signification, into the language of those early poets
p 71
of nature, Parmenides and Empedocles, and from thence into the works of
prose writers. We will not here enter into a discussion of the manner in
which, according to the Pythagorean views, Philolaus distinguishes between
Olympus, Uranus, or the heavens, and Cosmos, or how the same word, used in a
plural sense, could be applied to certain heavenly bodies (the planets)
revolving round one central focus of the world, or to groups of stars. In
this work I use the word Cosmos in conformity with the Hellenic usage of the
term subsequently to the time of Pythagorus, and in accordance with the
precise definition given of it in the treatise entitled 'De Mundo', which
was long erroneously attributed to Aristotle. It is the assemblage of all
things in heaven and earth, the universality of created things constituting
the perceptible world. If scientific terms had not long been diverted from
their true verbal signification, the present work ought rather to have borne
the title of 'Cosmography', divided into 'Uranography' and 'Geography.' The
Romans, in their feeble essays on philosophy, imitated the Greeks by
applying to the universe the term 'mundus', which, in its primary meaning,
indicated nothing more than ornament, and did not even imply order or
regularity in the disposition of parts. It is probable that the
introduction into the language of Latium of this technical term as an
equivalent for Cosmos, in its double signification, is due to Ennius,* who
was a follower of the Italian school, and the translator of the writings of
Epicharmus and some of his pupils on the Pythagorean philosophy.
[footnote] *See, on Ennius, the ingenious researches of Leopold Krahner, in
his 'Grundlinien zur Geschichte des Verfalls der Romischen Staats-Reigion',
1837, s. 41-45 (Outlines of the History of the Decay of the Established
Religion among the Romans). In all probability, Ennius did not quote from
writings of Epicharmus himself, but from poems composed in the name of that
philosopher, and in accordance with his views.
We would first distinguish between the physical 'history' and the physical
'description' of the world. The former, conceived in the most general sense
of the word, ought, if materials for writing it existed, to trace the
variations experienced by the universe in the course of ages from the new
stars which have suddenly appeared and disappeared in the vault of heaven,
from nebul¾ dissolving or condensing -- to the first stratum of cryptogamic
vegetation on the still imperfectly cooled surface of the earth, or on a
reef of coral uplifted from the depths of ocean. 'The physical description
of the world' presents a picture of all that exists in space -- of the
siimultaneous action of
p 72
natural forces, together with the phenomena which they produce.
But if we would correctly comprehend nature, we must not entirely or
absolutely separate the consideration of the present state of things from
that of the successive phases through which they have passed. We can not
form a just conception of their nature without looking back on the mode of
their formation. It is not organic matter alone that is continually
undergoing change, and being dissolved to form new combinations. The globe
itself reveals at every phase of its existence the mystery of its former
conditions.
We can not survey the crust of our planet without recognizing the traces of
the prior existence and destruction of an organic world. The sedimentary
rocks present a succession of organic forms, associated in groups, which
have successively displaced and succeeded each other. The different
super-imposed strata thus display to us the faunas and floras of different
epochs. In this sense the description of nature is intimately connected
with its history; and the geologist, who is guided by the connection
existing among the facts observed, can not form a conception of the present
without pursuing, through countless ages, the history of the past. In
tracing the physical delineation of the globe, we behold the present and the
past reciprocally incorporated, as it were, with one another; for the domain
of nature is like that of languages, in which etymological research reveals
a successive development, by showing us the primary condition of an idiom
reflected in the forms of speech in use at the present day. The study of
the material world renders this reflection of the past peculiarly manifest,
by displaying in the process of formation rocks of eruption and sedimentary
strata similar to those of former ages. If I may be allowed to borrow a
striking illustration from the geological relations by which the physiognomy
of a country is determined, I would say that domes of trachyte, cones of
basalt, lava streams ('coules')of amygdaloid with elongated and parallel
pores, and white deposits of pumice, intermixed with black scoriae, animate
the scenery by the associations of the past which they awaken, acting upon
the imagination of the enlightened observer like traditional records of an
earlier world. Their form is their history.
The sense in which the Greeks and Romans originally employed the word
'history' proves that they too were intimately convinced that, to form a
complete idea of the present state of the universe, it was necessary to
consider it in its successive
p 73
phases. It is not, however, in the definition given by Valerius Flaccus,*
but in the zoological writings of Aristotle, that the word 'history'
presents itself as an exposition of the results of experience and
observation.
[Footnote] *Aul. Gell., 'Nect. Att.', v., 18.
The physical description of the word by Pliny the elder bears the title of
'Natural History', while in the letters of his nephew it is designated by
the nobler term of 'History of Nature.' The earlier Greek historians did
not separate the description of countries from the narrative of events of
which they had been the theater. With these writers, physical geography and
history were long intimately associated, and remained simply but elegantly
blended until the period of the development of political interests, when the
agitation in which the lives of men were passed caused the geographical
portion to be banished from the history of nations, and raised into an
independent science.
It remains to be considered whether by the operation of thought, we may hope
to reduce the immense diversity of phenomena comprised by the Cosmos to the
unity of a principle, and the evidence afforded by rational truths. In the
present state of empirical knowledge, we can scarcely flatter ourselves with
such a hope. Experimental sciences, based on the observation of the
external world, can not aspire to completeness; the nature of things, and
the imperfection of our organs, are alike opposed to it. We shall never
succeed in exhausting the immeasurable riches of nature; and no generation
of men will ever have cause to boast of having comprehended the total
aggregation of phenomena. It is only by distributing them into groups that
we have been able, in the case of a few, to discover the empire of certain
natural laws, grand and simple as nature itself. The extent of this empire
will no doubt increase in proportion as physical sciences are more perfectly
developed. Striking proofs of this advancement have been made manifest in
our own day, in the phenomena of electro-magnetism, the propagation of
luminous waves and radiating heat. In the same manner, the fruitful
doctrine of evolution shows us how, in organic development, all that is
formed is sketched out beforehand, and how the tissues of vegetable and
animal matter uniformly arise from the multiplication and transformation of
cells.
The generalization of laws, which, being at first bounded by narrow limits,
had been applied solely to isolated groups of phenomena, acquires in time
more marked gradations, and gains in extent and certainty as long as the
process of reasoning
p 74
is applied strictly to analogous phenomena; but as soon as dynamical views
prove insufficient where the specific properties and heterogeneous nature of
matter come into play; it is to be feared that, by persisting in the pursuit
of laws, we may find our course suddenly arrested by an impassible chasm.
The principle of unity is lost sight of, and the guiding clew is rent
asunder whenever any specific and peculiar kind of action manifests itself
amid the active forces of nature. The law of equivalents and the numerical
proportions of composition, so happily recognized by modern chemists, and
proclaimed under the ancient form of atomic symbols, still remains isolated
and independent of mathematicl laws of motion and gravitation.
Those productions of nature which are objects of direct observation may be
logically distributed in classes, orders, and families. This form of
distribution undoubtedly sheds some light on descriptive natural history,
but the study of organized bodies, considered in their linear connection,
although it may impart a greater degree of unity and simplicity to the
distribution of groups, can not rise to the height of a classification based
on one sole principle of composition and internal organization. As
different gradations are presented by the laws of nature according to the
extent of the horizon, or the limits of the phenomena to be considered, so
there are likewise differently graduated phases in the investigation of the
external world. Empiricism originates in isolated views, which are
subsequently grouped according to their analogy or dissimilarity. To direct
observation succeeds, although long afterward, the wish to prosecute
experiments; that is to say, to evoke phenomena under different determined
conditions. The rational experimentalist does not proceed at hazard, but
acts under the guidance of hypotheses, founded on a half indistinct and more
or less just intuition of the connection existing among natural objects or
forces. That which has been conquered by observation or by means of
experiments, leads, by analysis and induction, to the discovery of empirical
laws. These are the phases in human intellect that have marked the
different epochs in the life of nations, and by means of which that great
mass of facts has been accumulated which constitutes at the present day the
solid basis of the natural sciences.
Two forms of abstraction conjointly regulate our knowledge, namely,
relations of 'quantity', comprising ideas of number and size, and relations
of 'quality', embracing the consideration of the specific properties and the
heterogeneous nature
p 75
of matter. The former, as being more accessible to the exercise of thought,
appertains to mathematics; the latter, from the apparent mysteries and
greater difficulties, falls under the domain of the chemical sciences. In
order to submit phenomena to calculation, recourse is had to a hypothetical
construction of matter by a combination of molecules and atoms, whose
number, form, position, and polarity determine, modify, or vary phenomena.
The mythical ideas long entertained of the imponderable substances and vital
forces peculiar to each mode of organization, have complicated our views
generally, and shed an uncertain light on the path we ought to pursue.
The most various forms of intuition have thus, age after age, aided in
augmenting the prodigious mass of empirical knowledge, which, in our own day
has been enlarged with ever-increasing rapidity. The investigating spirit
of man strives from time to time, with varying success, to break through
those ancient forms and symbols invented, to subject rebellious matter to
rules of mechanical construction.
We are still very far from the time when it will be possible for us to
reduce, by the operation of thought, all that we perceive by the senses, to
the unity of a rational principle. It may even be doubted if such a victory
could ever be achieved in the field of natural philosophy. The complication
of phenomena, and of the vast extent of the Cosmos, would seem to oppose
such a result; but even a partial solution of the problem -- the tendency
toward a comprehension of the phenomena of the universe -- will not the less
remain the eternal and sublime aim of every investigation of nature.
In conformity with the character of my former writings, as well as with the
labors in which I have been engaged during my scientific career, in
measurements, experiments, and the investigation of facts, I limit myself to
the domain of empirical ideas.
The exposition of mutually connected facts does not exclude the
classification of phenomena according to their rational connection, the
generalization of many specialities in the great mass of observations, or
the attempt to discover laws. Conceptions of the universe solely based upon
reason, and the principles of speculative philosophy, would no doubt assign
a still more exalted aim to the science of the Cosmos. I am far from
blaming the efforts of others solely because their success has hitherto
remained very doubtful. Contrary to the wishes and counsel of of those
profound and powerful thinkers who
p 76
have given new life to speculations which were already familiar to the
ancients, systems of natural philosophy have in our own country for some
time past turned aside the minds of men from the graver study of
mathematical and physical sciences. The abuse of better powers, which has
led many of our noble but ill-judging youth into the saturnalia of a purely
ideal science of nature, has been signalized by the intoxication of
pretended conquests, by a novel and fantastically symbolical phraseology,
and by a predilection for the formulae of a scholastic rationalism, more
contracted in its views than any known to the Middle Ages. I use the
expression "abuse of better powers," because superior intellects devoted to
philosophical pursuits and experimental sciences have remained strangers to
these saturnalia. The results yielded by an earnest investigation in the
path of experiment can not be at variance with a true philosophy of nature.
If there be any contradiction, the fault must lie either in the unsoundness
of speculation, or in the exaggerated pretensions of empiricism, which
thinks that more is proved by experiment than is actually derivable from it.
External nature may be opposed to the intellectual world, as if the latter
were not comprised within the limits of the former, or nature may be opposed
to art when the latter is defined as a manifestation of the intellectual
power of man; but these contrasts, which we find reflected in the most
cultivated languages, must not lead us to separate the sphere of nature from
that of mind, since such a separation would reduce the physical science of
the world to a mere aggregation of empirical specialities. Science does not
present itself to man until mind conquers matter in striving to subject the
result of experimental investigation to rational combinations. Science is
the labor of mind applied to nature, but the external world has no real
existence for us beyond the image reflected within ourselves through the
medium of the senses. As intelligence and forms of speech, thought and its
verbal symbols, are united by secret and indissoluble links, so does the
external world blend almost unconsciously to ourselves with our ideas and
feelings. "External phenomena," says Hegel, in his 'Philosophy of History',
"are in some degree translated in our inner representations." The objective
world, conceived and reflected within us by thought, is subjected to the
eternal and necessary conditions of our intellectual being. The activity of
the mind exercises itself on the elements furnished to it by the perceptions
of the senses. Thus, in the
p 77
early ages of mankind, there manifests itself in the simple intuition of
natural facts, and in the efforts made to comprehend them, the germ of the
philosophy of nature. These ideal tendencies vary, and are more or less
powerful, according to the individual characteristics and moral dispositions
of nations, and to the degrees of their mental culture, whether attained
amid scenes of nature that excite or chill the imagination.
History has preserved the record of the numerous attempts that have been
made to form a rational conception of the whole world of phenomena, and to
recognize in the universe the action of one sole active force by which
matter is penetrated, transformed, and animated. These attempts are traced
in classical antiquity in those treatises on the principles of things which
emanated from the Ionian school, and in which all the phenomena of nature
were subjected to hazardous speculations, based upon a small number of
observations. By degrees, as the influence of great historical events has
favored the development of every branch of science supported by observation,
that ardor has cooled which formerly led men to seek the essential nature
and connection of things by ideal construction and in purely rational
principles. In recent times, the mathematical portion of natural philosophy
has been most remarkably and admirably enlarged. The method and the
instrument (analysis) have been simultaneously perfected. That which has
been acquired by means so different -- by the ingenious application of
atomic suppositions, by the more general and intimate study of phenomena,
and by the improved construction of new apparatus -- is the common property
of mankind, and shouldnot, in our opinion, now, more than in ancient times,
be withdrawn from the free exercise of speculative thought.
It can not be denied that in this process of thought, the results of
experience have had to contend with many disadvantages; we must not,
therefore, be surprised if, in the perpetual vicissitude of theoretical
views, as is ingeniously expressed by the author of 'Giordano Bruno', "most
men see nothing in philosophy but a succession of passing meteors, while
even the grander forms in which she has revealed herself share the fate of
comets, bodies that do not rank in popular opinion among the eternal and
permanent works of nature,
p 78
but are regarded as mere fugitive apparitions of igncor vapor."
[Footnote] *Schelling's Bruno, 'eber das Gottliche und Naturaliche Princip.
der Dinge', 181 (Bruno, on the 'Divine and Natural Principle of Things')
We would here remark that the abuse of thought, and the false track it too
often pursues, ought not to sanction an opinion derogatory to the intellect,
which would imply that the domain of mind is essentially a world of vague
fantastic illusions, and that the treasures accumulated by laborious
observations in philosophy are powers hostile to its own empire. It does
not become the spirit which characterizes the present age distrustfully to
reject every generalization of views and every attempt to examine into the
nature of things by the process of reason and induction. It would be a
denial of the dignity of human nature and the relative importance of the
faculties with which we are endowed, were we to condemn at one time austere
reason engaged in investigating causes and their natural connections, and at
another that exercise of the imagination which prompts and excites
discoveries by its creative powers.
This material taken from pages 79 to 111
COSMOS: A Sketch of the Physical Description of the Universe, Vol. 1
by Alexander von Humboldt
Translated by E C Otte
from the 1858 Harper & Brothers edition of Cosmos, volume 1
--------------------------------------------------
p 79
COSMOS.
-------------------------
DELINEATION OF NATURE. GENERAL REVIEW OF NATURAL PHENOMENA.
WHEN the human mind first attempts to subject to its control the world of
physical phenomena, and strives by meditative contemplation to penetrate the
rich luxuriance of living nature, and the mingled web of free and restricted
natural forces, man feels himself raised to a height from whence, as he
embraces the vast horizon, individual things blend together in varied
groups, and appear as if shrouded in a vapory
vail. These figurative expressions are used in order to illustrate the
point of view from whence we would consider the universe both in its
celestial and terrestrial sphere. I am not insensible of the boldness of
such an undertaking. Among all the forms of exposition to which these pages
are devoted, there is none more difficult than the general delineation of
nature, which we purpose sketching, since we must not allow ourselves to be
overpowered by a sense of the stupendous richness and variety of the forms
presented to us, but must dwell only on the consideration of masses either
possessing actual magnitude, or borrowing its semblance from the
associations awakened within the subjective sphere of ideas. It is by a
separation and classification of phenomena by an intuitive insight into the
play of obscure forces, and by animated expressions, in which the
perceptible spectacle is reflected with vivid truthfulness, that we may hope
to comprehend and describe the 'universal all' [Greek words] in a manner
worthy of the dignity of the word 'Cosmos' in its signification of
'universe, order of the world', and 'adornment' of this universal order.
May the immeasurable diversity of phenomena which crowd into the picture of
nature in no way detract from that harmonious impression of rest and unity
which is the ultimate object of every literary or purely artistical
composition.
Beginning with the depths of space and the regions of remotest nebulae, we
will gradually descend through the starry zone to which our solar system
belongs, to our own terrestrial spheroid, circled by air and ocean, there to
direct our attention
p 80
to its form, temperature, and magnetic tension, and to consider the fullness
of organic life unfolding itself upon its surface beneath the vivifying
influence of light. In this manner a picture of the world may, with a few
strokes, be made to include the realms of infinity no less than the minute
microscopic animal and vegetable organisms which exist in standing waters
and on the weather-beaten surface of our rocks. All that can be perceived
by the senses, and all that has been accumulated up to the present day by an
attentive and variously directed study of nature, constitute the materials
from which this representation is to be drawn, whose character is an
evidence of its fidelity and truth. But the descriptive picture of nature
which we purpose drawing must not enter too fully into detail, since a
minute enumeration of all vital forms, natural objects, and processes is not
requisite to the completeness of the undertaking. The delineator of nature
must resist the tendency toward endless division, in order to avoid the
dangers presented by the very abundance of our empirical knowledge. A
considerable portion of the qualitative properties of matter -- or, to speak
more in accordance with the language of natural philosophy, of the
qualitative expression of forces -- is doubtlessly still unknown to us, and
the attempt perfectly to represent unity in diversity must therefore
necessarily prove unsuccessful. Thus, besides the pleasure derived and
tinged with a shade of sadness, an unsatisfied longing for something beyond
the present -- a striving toward regions yet unknown and unopened. Such a
sense of longing binds still faster the links which, in accordance with the
supreme laws of our being, connect the material with the ideal world, and
animates the mysterious relation existing between that which the mind
receives from without, and that which it reflects from its own depths to the
external world. If, then, nature (understanding by the term all natural
objects and phenomena) be illimitable in extent and contents, it likewise
presents itself to the human intellect as a problem which can not be
grasped, and whose solution is impossible, since it requires a knowledge of
the combined action of all natural forces. Such an acknowledgement is due
where the actual state and prospective development of phenomena constitute
the sole objects of direct investigation, which does not venture to depart
from the strict rules of induction. But, although the incessant effort to
embrace nature in its universality may remain unsatisfied, the history of
the contemplation of the universe (which
p 81
will be considered in another part of this work) will teach us how, in the
course of ages, mankind has gradually attained to a partial insight into the
relative dependence of phenomena. My duty is to depict the results of our
knowledge in all their bearings with reference to the present. In all that
is subject to motion and change in space, the ultimate aim, the very
expression of physical laws, depend upon 'mean numerical values', which show
us the constant amid change, and the stable amid apparent fluctuations of
phenomena. Thus the progress of modern physical science is especially
characterized by the attainment and the rectification of the mean values of
certain quantities by means of the processes of weighing and measuring; and
it may be said, that the only remaining and widely-diffused hieroglyphic
characters still in our writing -- 'numbers' -- appear to us again, as
powers of the Cosmos, although in a wider sense than that applied to them by
the Italian School.
The earnest investigator delights in the simplicity of numerical relations,
indicating the dimensions of the celestial regions, the magnitudes and
periodical disturbances of the heavenly bodies, the triple elements of
terrestrial magnetism, the mean pressure of the atmosphere, and the quantity
of heat which the sun imparts in each year, and in every season of the year,
to all points of the solid and liquid surface of our planet. These sources
of enjoyment do not, however, satisfy the poet of Nature, or the mind of the
inquiring many. To both of these the present state of science appears as a
blank, now that she answers doubtingly, or wholly rejects as unanswerable,
questions to which former ages deemed they could furnish satisfactory
replies. In her severer aspect, and clothed with less luxuriance, she shows
herself deprived of that seductive charm with which a dogmatizing and
symbolizing physical philosophy knew how to deceive the understanding and
give the rein to imagination. Long before the discovery of the New World,
it was believed that new lands in the Far West might be seen from the shores
of the Canaries and the Azores. These illusive images were owing, not to
any extraordinary refraction of the rays of light, but produced by an eager
longing for the distant and the unattained. The philosophy of the Greeks,
the physical views of the Middle Ages, and even those of a more recent
period, have been eminently imbued with the charm springing from similar
illusive phantoms of the imagination. At the limits of circumscribed
knowledge, as from some lofty island shore, the eye delights to penetrate
p 82
to distant regions. The belief in the uncommon and the wonderful lends a
definite outline to every manifestation of ideal creation; and the realm of
fancy -- a fairy-land of cosmological, geognostical, and magnetic visions --
becomes thus involuntarily blended with the domain of reality.
Nature, in the manifold signification of the word -- whether considered as
the universality of all that is and ever will be -- as the inner moving
force of all phenomena, or as their mysterious prototype -- reveals itself
to the simple mind and feelings of man as something earthly, and closely
allied to himself. It is only within the animated circles of organic
structure that we feel ourselves peculiarly at home. Thus, wherever the
earth unfolds her fruits and flowers, and gives food to countless tribes of
animals, there the image of nature impresses itself most vividly upon our
senses. The impression thus produced upon our minds limits itself almost
exclusively to the reflection of the earthly. The starry vault and the wide
expanse of the heavens belong to a picture of the universe, in which the
magnitude of masses, the number of congregated suns and faintly glimmering
nebulae, although they excite our wonder and astonishment, manifest
themselves to us in apparent isolation, and as utterly devoid of all
evidence of their being the scenes of organic life. Thus, even in the
earliest physical views of mankind, heaven and earth have been separated and
opposed to one another as an upper and lower portion of space. If, then, a
picture of nature were to correspond to the requirements of contemplation by
the senses, it ought to begin with a delineation of our native earth. It
should depict, first, the terrestrial planet as to its size and form; its
increasing density and heat at increasing depths in its superimposed solid
and liquid strate; the separation of sea and land, and the vital forms
animating both, developed in the cellular tissues of plants and animals; the
atmospheric ocean, with its waves and currents, through which pierce the
forest-crowned summits of our mountain chains. After this delineation of
purely telluric relations, the eye would rise to the celestial regions, and
the Earth would then, as the well-known seat of organic development, be
considered as a planet, occupying a place in the series of those heavenly
bodies which circle round one of the innumerable host of self-luminous
stars. This succession of ideas indicates the course pursued in the
earliest stages of perceptive contemplation, and reminds us of the ancient
conception of the "sea-girt disk of earth," supporting the vault of heaven.
It begins to exercise in action
p 83
at the spot where it originated, and passes from the consideration of the
known to the unknown, of the near to the distant. It corresponds with the
method pursued in our elementary works on astronomy (and which is so
admirable in a mathematical point of view), of proceeding from the apparent
to the real movements of the heavenly bodies.
Another course of ideas must, however, be pursued in a work which proposes
merely to give an exposition of what is known -- of what may in the present
state of our knowledge be regarded as certain, or as merely probable in a
greater or lesser degree -- and does not enter into a consideration of the
proofs on which such results have been based. Here, therefore, we do not
proceed from the subjective point of view of human interests. The
terrestrial must be treated only as grand and free, uninfluenced by motives
of proximity, social sympathy, or relative utility. A physical cosmography
-- a picture of the universe -- does not begin, therefore, with the picture
of the universe -- does not begin, therefore, with the terrestrial, but with
that which fills the regions of space. But as the sphere of contemplation
contracts in dimension our perception of the richness of individual parts,
the fullness of physical phenomena, and of the heterogeneous properties of
matter becomes enlarged. From the regions in which we recognize ony the
dominion of the laws of attraction, we descend to our own planet, and to the
intricate play of terrestrial forces. The method here described for the
delineation of nature is opposed to that which mst be pursued in
establishing conclusive results. The one enumerates what the other
demonstrates.
Man learns to know the external world through the organs of the senses.
Phenomena of light proclaim the existence of matter in remotest space, and
the eye is thus made the medium through which we may contemplate the
universe. The discovery of telescopic vision more than two centuries ago,
has transmitted to latest generations a power whose limits are as yet
unattained.
The first and most general consideration of the Cosmos is that of the
'contents of space' -- the distribution of matter, or of creation, as we are
wont to designate the assemblage of all that is and ever will be developed.
We see matter either agglomerated into rotating, revolving spheres of
different density and size, or scattered through space in the form of
self-luminous vapor. If we consider first the cosmical vapor dispersed in
definite nebulous spots, its state of aggregation will
p 84
appear constantly to vary, sometimes appearing separated into round or
elliptical disks, single or in pairs, occasionally connected by a thread of
light; while, at another time, these nebulae occur in forms of larger
dimensions, and are either elongated, or variously branched or fan-shaped or
appear like well-defined rings, including a dark interior. It is
conjectured that these bodies are undergoing variously developed formative
processes, as the cosmical vapor becomes condensed in conformity with the
laws of attraction, either round one or more of the nuclei. Between two and
three thousand of such unresolvable nebulae, in which the most powerful
telescopes have hitherto been unable to distinguish the presence of stars,
have been counted, and their positions determined.
The genetic evolution -- that perpetual state of development which seems to
affect this portion of the regions of space -- has led philosophical
observers to the discovery of the analogy existing among organic phenomena.
As in our forests we see the same kind of tree in all the various stages of
its growth, and are thus enabled to form an idea of progressive, vital
development, so do we also in the great garden of the universe, recognise
the most different phases of sidereal formation. The process of
condensation, which formed a part of the doctrines of Anaximenes and of the
Ionian School, appears to be going on before our eyes. This subject of
investigation and conjecture is especially attractive to the imagination,
for in the study of the animated circles of nature, and of the action of all
the moving forces of the universe, the charm that exercises the most
powerful influence on the mind is derived less from a knowledge of that
which 'is' than from a perception of that which 'will be', even though the
latter be nothing more than a new condition of a known material existence;
for of actual creation, of origin, the beginning of existence from
non-existence, we have no experience, and can therefore form no conception.
A comparison of the various causes influencing the development manifested by
the greater or less degree of condensation in the interior of nebulae, no
less than a successive course of direct observations, have led to the belief
that changes of form have been recognized first in Andromeda, next in the
constallation Argo, and in the isolated filamentous portion of the nebula in
Orion. But want of uniformity in the power of the instruments employed,
different conditions of our atmosphere, and other optical relations, render
a part of the results invalid as historical evidence.
p 85
'Nebulous stars' must not be confounded either with irregularly-shaped
nebulous spots, properly so called, whose separate parts have an unequal
degree of brightness (and which may, perhaps, become concentrated into stars
as their circumference contracts), nor with the so-called planetary nebulae,
whose circular or slightly oval disks manifest in all their parts a
perfectly uniform degree of faint light. 'Nebulous stars' are not merely
accidental bodies projected upon a nebulous ground, but are a part of the
nebulous matter constituting one mass with the body which it surrounds. The
not unfrequently considerable magnitude of their apparent diameter, and the
remote distance from which they are revealed to us, show that both the
planetary nebulae and the nebulous stars must be of enormous dimensions.
New and ingenious considerations of the different influence exercised by
distance* on the intensity of light of a disk of appreciable diameter, and
of a single self-luminous point, render it not improbable that the planetary
nebulae are very remote nebulous stars, in which the difference between the
central body and the surrounding nebulous covering can no longer be detected
by our telescopic instruments.
[footnote] * The optical considerations relative to the difference
presented by a single luminous point, and by a disk subtending an
appreciable angle, in which the intensity of light is constant at every
distance, are explained in Arago's 'Analyse des Travaux de Sir William
Herschel' ('Annuaire du Bureau des Long.', 1842, p. 410-412, and 441).
The magnificent zones of the southern heavens, between 50 degrees and 80
degrees, are especially rich in nebulous stars, and in compressed
unresolvable nebua e. The larger of the two Magellanic clouds, which circle
round the starless, desert pole of the south, appears, according to the most
recent researches,* as "a collection of clusters of stars, composed of
globular clusters and nebulae of different magnitude, and of large nebulous
spots
p 86
not resolvable, which, producing a general brightness in the field of view,
form, as it were, the back-ground of the picture."
[footnote] *The two Magellanic clouds, Nubecula major and Nubecula minor,
are very remarkable objects. The larger of the two is an accumulated mass
of stars, and consists of clusters of stars of irregular form, either
conical masses or nebulae of different magnitudes and degrees of
condensation. This is interspersed with nebulous spots, not resolvable into
stars, but which are probably 'star dust', appearing only as a general
radiance upon the telescopic field of a twenty-feet reflector, and forming a
luminous ground on which other objects of striking and indescribable form
are scattered. In no other portion of the heavens are so many nebulous and
stellar masses thronged together in an equally small space. Nubecula minor
is much less beautiful, has more unresolvable nebulous light, while the
stellar masses are fewer and fainter in intensity. -- (From a letter of Sir
John Herschel, Feldhuysen, Cape of Good Hope, 13th June, 1836.)
The appearance of these clouds, of the brightly-beaming constellation Argo,
of the Milky Way between Scorpio, the Centaur, and the Southern Cross, the
picturesque beauty, if one may so speak, of the whole expanse of the
southern celestial hemisphere, has left upon my mind an ineffaceable
impression. The zodiacal light, which rises in a pyramidal form, and
constantly contributes, by its mild radiance, to the external beauty of the
tropical nights, is either a vast nebulous ring, rotating between the Earth
and Mars, or, less probably, the exterior stratum of the solar atmosphere.
Besides these luminous clouds and nebulae of definite form, exact and
corresponding observations indicate the existence and the general
distribution of an apparently non-luminous, infinitely-divided matter, which
posssesses a force of resistance and manifests its presence in Encke's, and
perhaps also in Biela's comet, by diminishing their eccentricity and
shortening their period of revolution. Of this impending, ethereal, and
cosmical matter, it may be supposed that it is in motion; that it
gravitates, notwithstanding its original tenuity; that it is condensed in
the vicinity of the great mass of the Sun; and, finally, that it may, for
myriads of ages, have been augmented by the vapor emanating from the tails
of comets.
If we now pass from the consideration of the vaporous matter of the
immeasurable regions of space [(Greek)*] -- whether scattered without
definite form and limits, it exists as a cosmical other, or is condensed
into nebulous spots, and becomes comprised among the solid agglomerated
bodies of the universe -- we approach a class of phenomena exclusively
designated by the form of stars, or as the sidereal world.
[footnote] *I should have made use, in the place of garden of the universe,
of the beautiful expression [Greek], borrowed by Hesychius from an unknown
poet, if [Greek] had not rather signified in general an inclosed space. The
connection with the German 'garten' and the English 'garden', 'gards' in
Gothic (derived according to Jacob Grimm, from 'gairdan', 'to gird'), is,
however, evident, as is likewise the affinity with the Slavonic 'grad',
'gorod', and as Pott remarks, in his 'Etymol. Forschungen', th. i., s. 144
(Etymol. Researches), with the Latin 'chors', whence we have the Spanish
'corte', the French 'cour', and the English word 'court', together with the
Ossetic 'khart'. To these may be further added the Scandinavian 'gard',**
'gard', a place inclosed, as a court, or a country seat, and the Persian
'gerd', 'gird', a district, a circle, a princely country seat, a castle or
city, as we find the term applied to the names of places in Firdusi's
Schahnameh, as 'Siyawakschgird', 'Darabgird', etc.
** (This word is written 'gaard' in the Danish) -- Tr.
p 87
Here, too, we find differences existing in the solidity or density of the
spheroidally agglomerated matter. Our own solar system presents all stages
of 'mean' density (or of the relation of 'volume' to 'mass'.) On comparing
the planets from Mercury to Mars with the Sun and with Jupiter, and these
two last named with the yet inferior density of Saturn, we arrive, by a
descending scale -- to draw our illustration from the terrestrial substances
-- at the respective densities of antimony, honey, water, and pine wood. In
comets, which actually constitute the most considerable portion of our solar
system with respect to the number of individual forms, the concentrated
part, usually termed the 'head', or 'nucleus', transmits sidereal light
unimpaired. The mass of a comet probably in no case equals the five
thousandth part of that of the earth, so dissimilar are the formative
processes manifested in the original and perhaps still progressive
agglomerations of matter. In proceeding from general to special
considerations, it was particularly desirable to draw attention to this
diversity, not merely as a possible, but as an actually proved fact.
The purely speculative conclusions arrived at by Wright, Kant, and Lambert,
concerning the general structural arrangement of the universe, and of the
distribution of matter in space, have been confirmed by Sir William
Herschel, on the more certain path of observation and measurement. That
great and enthusiastic, although cautious observer, was the first to sound
the depths of heaven in order to determine the limits and form of the starry
stratum which we inhabit, and he, too, was the first who ventured to throw
the light of investigation upon the relations existing between the position
and distance of remote nebulae and our own portion of the sidereal universe.
William Herschel, as is well expressed in the elegant inscription on his
monument at Upton, broke through the inclosures of heaven ('caelorum
perrupit claustra'), and, like another Columbus, penetrated into an unknown
ocean, from which he beheld coasts and groups of islands, whose true
position it remains for future ages to determine.
Considerations regarding the different intensity of light in stars, and
their relative number, that is to say, their numerical frequency on
telescopic fields of equal magnitude, have led to the assumption of unequal
distances and distribution in space in the strata which they compose. Such
assumptions, in as far as they may lead us to draw the limits of the
individual portions of the universe, can not offer the same degree of
mathematical certainty as that which may be attained in all that
p 88
relates to our solar system, whether we consider the rotation of double
stars with unequal velocity round one common center of gravity, or the
apparent or true movements of all the heavenly bodies. If we take up the
physical description of the universe from the remotest nebulae, we may be
inclined to compare it with the mythical portions of history. The one
begins in the obscurity of antiquity, the other in that of inaccessible
space; and at the point where reality seems to flee before us, imagination
becomes doubly incited to draw from its own fullness, and give definite
outline and permanence to the changing forms of objects.
If we compare the regions of the universe with one of the island-studded
seas of our own planet, we may imagine matter to be distributed in groups,
either as unresolvable nebulae of different ages, condensed around one or
more nuclei, or as already agglomerated into clusters of stars, or isolated
spheroidal bodies. The cluster of stars, to which our cosmical island
belongs, forms a lens-shaped, flattened stratum, detached on every side,
whose major axis is estimated at seven or eight hundred, and its minor one
at a hundred and fifty times the distance of Sirius. It would appear, on
the supposition that the parallax of Sirius is not greater than that
accurately determined for the brightest star in the Centaur (0".9128), that
light traverses one distance of Sirius in three years, while it also
follows, from Bessel's earlier excellent Memoir* on the parallax of the
remarkable star 61 Cygni (0".3483), (whose considerable motion might lead to
the inference of great proximity), that a period of nine years and a quarter
is required for the transmission of light from this star to our planet.
[footnote] *See Maclear's "Results from 1839 to 1840," in the 'Trans. of
the Astronomical Soc.', vol. xii., p. 370, on 'a' Centauri, the probable
mean error being 0".0649. For 61 Cygni, see Bessel, in Schumacher's
'Jahrbuch', 1839, s. 47, and Schumacher's 'Astron. Nachr.', bd. xviii., s.
401, 402, probable mean error, 0".0141. With reference to the relative
distances of stars of different magnitudes, how those of the third magnitude
may probably be three times more remote, and the manner in which we
represent to ourselves the material arrangement of the starry strata, I have
found the following remarkable passage in Kepler's 'Epitome Astronomiae
Copernicanae', 1618, t. i., lib. 1, p. 34-39: "Sol hic noster nil aliud est
quam una ex fixis, nobis major et clarior visa, quia propior quam fixa.
Pone terram stare ad latus, una semi-diametro via e lactea e, tunc ha ec via
lactea apparebit circulus parvus, vel ellipsis parva, tota declinans ad
latus alterum; eritque simul uno intuitu conspicua, quae nunc no potest nisi
dimidia conspici quovis momento. Itaque fix arum spha era non tantum orbe
stellarum, sed etiam circulo lactis versus not deorsum est terminata."
Our starry stratum is a disk of inconsiderable thickness, divided a
p 89
third of its length into two branches; it is supposed that we are near this
division, and nearer to the region of Sirius than to the constellation
Aquila, almost in the middle of the stratum in the line of its thickness or
minor axis.
This position of our solar system, and the form of the whole discoidal
stratum, have been inferred from sidereal scales, that is to say, from that
method of counting the stars to which I have already alluded, and which is
based upon the equidistant subdivision of the telescopic field of view. The
relative depth of the stratum in all directions is measured by the greater
or smaller number of stars appearing in each division. These divisions give
the length of the ray of vision in the same manner as we measure the depth
to which the plummet has been thrown, before it reaches the bottom, although
in the case of a starry stratum there can not, correctly speaking, be any
idea of depth, but merely of outer limits. In the direction of the longer
axis, where the stars lie behind one another, the more remote ones appear
closely crowded together, united, as it were, by a milky-white radiance or
luminous vapor, and are perspectively grouped, encircling as in a zone, the
visible vault of heaven. This narrow and branched girdle, studded with a
radiant light, and here and there interrupted by dark spots, deviates only
by a few degrees from forming a perfect large circle round the concave
sphere of heaven, owing to our being near the center of the large starry
cluster, and almost on the plane of the Milky Way. If our planetary system
were far 'outside' this cluster, the Milky Way would appear to telescopic
vision as a ring, and at a still greater distance as a resolvable discoidal
nebula.
Among the many self-luminous moving suns, erroneously called 'fixed stars',
which constitute our cosmical island, our own sun is the only one known by
direct observation to be a 'central body' in its relations to spherical
agglomerations of matter directly depending upon and revolving round it,
either in the form of planets, comets, or aerolite asteroids. As far as we
have hitherto been able to investigate 'multiple' stars (double stars or
suns), these bodies are not subject, with respect to relative motion and
illumination, to the same planetary dependence that characterizes our own
solar system. Two or more self-luminous bodies, whose planets and moon, if
such exist, have hitherto escaped our telescopic powers of vision, certainly
revolve around one common center of gravity; but this is in a portion of
space which is probably occupied merely by unagglomerated matter or cosmical
vapor, while in our system
p 90
the center of gravity is often comprised within the innermost limits of a
'visible' central body. If, therefore, we regard the Sun and the Earth, or
the Earth and the Moon, as double-stars, and the whole of our planetary
solar system as a multiple cluster of stars, the analogy thus suggested must
be limited to the universality of the laws of attraction in different
systems, being alike applicable to the independent processes of light and to
the method of illumination.
For the generalization of cosmical views, corresponding with the plan we
have proposed to follow in giving a delineation of nature or of the
universe, the solar system to which the Earth belongs may be considered in a
two-fold relation: first, with respect to the different classes of
individually agglomerated matter, and the relative size, conformation,
density, and distance of the heavenly bodies of this system; and secondly,
with reference to other portions of our starry cluster, and of the changes
of position of its central body, the Sun.
The solar system, that is to say, the variously-formed matter circling round
the Sun, consists, according to the present state of our knowledge of
'eleven primary planets',* eighteen satellites
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or secondary planets, and myriads of comets, three of which, known as the
"planetary comets," do not pass beyond the narrow limits of the orbits
described by the principal planets.
[footnote] * (Since the publication of Baron Humboldt's work in 1845,
several other planets have been discovered, making the number of those
belonging to our planetary system 'sixteen' instead of 'eleven'. Of these,
Astrea, Hebe, Flora, and Iris are members of the remarkable group of
asteroids between Mars and Jupiter. Astrea and Hebe were discovered by
Hencke at Driesen, the one in 1846 and the other in 1847; Flora and Iris
were both discovered in 1847 by Mr. Hind, at the South Villa Observatory,
Regent's Park. It would appear from the latest determinations of their
elements, that the small planets have the following order with respect to
mean distance from the Sun: Flora, Iris, Vesta, Hebe, Astrea, Juno, Ceres,
Pallas. Of these, Flora has the shortest period (about 3 1/4 years). The
planet Neptune, which, after having been predicted by several astronomers,
was actually observed on the 25th of September, 1846, is situated on the
confines of our planetary system beyond Uranus. The discovery of this
planet is not only highly interesting from the importance attached to it as
a question of science, but also from the evidence it affords of the care and
unremitting labor evinced by modern astronomers in the investigation and
comparison of the older calculations, and the ingenious application of the
results thus obtained to the observation of new facts. The merit of having
paved the way for the discovery of the planet Neptune is due to M. Bouvard,
who, in his persevering and assiduous efforts to deduce the entire orbit of
Uranus from observations made during the forty years that succeeded the
discovery of that planet in 1781, found the results yielded by theory to be
at variance with fact, in a degree that had no parallel in the history of
astronomy. This startling discrepancy, which seemed only to gain additional
weight from every attempt made by M. Bouvard to correct his calculations,
led Leverrier, after a careful modification of the tables of Bouvard, to
establish the proposition that there was "a formal incompatibility between
the observed motions of Uranus and the hypothesis that he was acted on
'only' by the Sun and known planets, according to the law of universal
gravitation." Pursuing this idea, Leverrier arrived at the conclusion that
the disturbing cause must be a 'planet', and finally, after an amount of
labor that seems perfectly overwhelming, he, on the 31st of August, 1846,
laid before the French Institute a paper, in which he indicated the exact
spot in the heavens where this new planetary body would be found, giving the
following data for its various elements: mean distance from the Sun, 36.154
times that of the Earth; period of revolution, 217.387 years; mean long.,
Jan. 1st, 1847, 318 degrees 47'; mass, 1/9300th; heliocentric long., Jan
1st1847, 326 degrees 32'. Essential difficulties still intervened, however,
and as the remoteness of the planet rendered it improbable that its disk
would be discernible by any telescopic instrument, no other means remained
for detecting the suspected body but its planetary motion, which could only
be ascertained by mapping, after every observation, the quarter of the
heavens scanned, and by a comparison of the various maps. Fortunately for
the verification of Leverrier's predictions, Dr. Bremiker had just completed
a map of the precise region in which it was expected the new planet would
apper, this being one of a series of maps made for the Academy of Berlin, of
the small stars along the entire zodiac. By means of this valuable
assistance, Dr. Galle, of the Berlin Observatory, was led, on the 25th of
September, 1846, by the discovery of a star of the eighth magnitude, not
recorded in Dr. Bremiker's map, to make the first observation of the planet
predicted by Leverrier. By a singular coincidence, Mr. Adams, of Cambridge,
had predicted the appearance of the planet simultaneously with M. Leverrier;
but by the concurrence of several circumstances much to be regretted, the
world at large were not made acquainted with Mr. Adams's valuable discovery
until subsequently to the period at which Leverrier published his
observations. As the data of Leverrier and Adams stand at present, there is
a discrepancy between the predicted and the true distance, and in some other
elements of the planet; it remains therefore, for these or future
astronomers to reconcile theory with fact, or perhaps, as in the case of
Uranus, to make the new planet the means of leading to yet greater
discoveries. It would appear from the most recent observations, that the
mass of Neptune, instead of being, as at first stated, 1/9300th, is only
about 1/23000th that of the Sun, while its periodic time is now given with a
greater probability at 166 years, and its mean distance from the Sun nearly
30. The planet appears to have a ring, but as yet no accurate observations
have been made regarding its system of satellites. See 'Trans. Astron.
Soc.', and 'The Planet Neptune', 1848, by J. P. Nicholl.) -- Tr.
We may, with no incondsiderable degree of probability, include within the
domain of our Sun, in the immediate sphere of its central force, a rotating
ring of vaporous matter, lying probably between the orbits of Venus and
Mars, but certainly beyond that of the Earth,* which appears to us in
p 92
a pyramidal form, and is known as the 'Zodiacal Light'; and a host of very
small asteroids, whose orbits either intersect, or very nearly approach,
that of our earth, and which present us with the phenomena of aerolites and
falling or shooting stars.
[footnote] * "If there should be molecules in the zones diffused by the
atmosphere of the Sun of too volatile a nature either to combine with one
another or with the planets, we must suppose that they would, in circling
round that luminary, present all the appearances of zodiacal light, without
opposing any appreciable resistance to the different bodies composing the
planetary system, either owing to their extreme rarity, or to the similarity
existing between their motion and that of the planets with which they come
in contact." -- Laplace, 'Expos. du Syst. du Monde' (ed. 5), p. 415.
When we consider the complication of variously-formed bodies which revolve
round the Sun in orbits of such dissimilar eccentricity--although we may not
be disposed, with the immortal author of the 'Mecanique Celeste', to regard
the largr number of comets as nebulous stars, passing from one central
system to another,* we yet can not fail to acknowledge that the planetary
system, especially so called (that is, the group of heavenly bodies which,
together with their satellites, revolve with but slightly eccentric orbits
round the Sun), constitutes but a small portion of the whole system with
respect to individual numbers, if not to mass.
[footnote] *Laplace, 'Exp. du Syst. du Monde', p. 396, 414.
It has been proposed to consider the telescopic planets, Vesta, Juno, Ceres,
and Pallas, with their more closely intersecting, inclined, and eccentric
orbits, as a zone of separation, or as a middle group in space; and if this
view be adopted, we shall discover that the interior planetary group
(consisting of Mercury, Venus, the Earth, and Mars) presents several very
striking contrasts* when compared with the exterior group, comprising
Jupiter, Saturn, and Uranus.
[footnote] *Littrow, 'Astronomie', 1825, bd.xi., 107. MÂdler, 'Astron.',
1841, ¤ 212. Laplace, 'Exp. du Syst. du Monde', p. 210.
The planets nearest the Sun, and consequently included in the inner group,
are of more moderate size, denser, rotate more slowly and with nearly equal
velocity (their periods of revolution being almost all about 24 hours), are
less compressed at the poles, and with the exception of one, are without
satellites. The exterior planets, which are further removed from the Sun,
are very considerably larger, have a density five times less, more than
twice as great a velocity in the period of their rotation round their axes,
are more compressed at the poles, and if six satellites may be ascribed to
Uranus, have a quantitative preponderance in the number of their attendant
moons, which is as seventeen to one.
p 93
Such general considerations regarding certain characteristic properties
appertaining to whole groups, can not, however, be applied with equal
justice to the individual planets of every group, nor to the relations
between the distances of the revolving planets from the central body, and
their absolute size, density, period or rotation, eccentricity, and the
inclination of their orbits and the axes. We know as yet of no inherent
necessity, no mechanical natural law, similar to the one which teaches us
that the squares of the periodic times are proportional to the cubes of the
major axes, by which the above-named six elements of the planetary bodies
and the form of their orbit are made dependent either on one another, or on
their mean distance from the Sun. Mars is smaller than the Earth and Venus,
although further removed from the Sun than these last-named planets,
approaching most nearly in size to Mercury, the nearest planet to the Sun.
Saturn is smaller than Jupiter, and yet much larger than Uranus. The zone
of the telescopic planets, which have so inconsiderable a volume,
immediately procede Jupiter (the greatest in size of any of the planetary
bodies), if we consider them with regard to distance from the Sun; and yet
the disks of these small asteroids, which scarcely admit of measurement,
have an areal surface not much more than half that of France, Madagascar, or
Borneo. However striking may be the extremely small density of all the
colossal planets, which are furthest removed from the Sun, we are yet unable
in this respect to recognize any regular succession.*
[footnote] *See Kepler, on the increasing density and volume of the planets
in proportion with their increase of distance from the Sun, which is
described as the densest of all the heavenly bodies; in the 'Epitome Astran.
Copern. in' vii. 'libros digesta', 1618-1622, p. 420. Leibnitz also
inclined to the opinions of Kepler and Otto von Guericke, that the planets
increase in volume in proportion to their increase of distance from the Sun.
See his letter to the Magdeburg Burgomaster (Mayence, 1671), in Leibnitz,
'Deutschen Schriften, herausg. von Guhrauer', th. i., 264.
Uranus appears to be denser than Saturn, even if we adopt the smaller mass,
1/24605, assumed by Lamont; and, notwithstanding the inconsiderable
difference of density observed in the innermost planetary group,* we find
both Venus and Mars less dense than the Earth, which lies between them.
[footnote] *On the arrangement of masses, see Encke, in Schum., 'Astr.
Nachr', 1843 Nr. 488, 114.
The time of rotation certainly diminishes with increasing solar distance,
but yet it is greater in Mars than in the Earth, and in Saturn than in
Jupiter. The elliptic
p 94
orbits of Juno, Pallas, and Mercury have the greatest degree of
eccentricity, and Mars and Venus, which immediately follow each other, have
the least. Mercury and Venus exhibit the same contrasts that may be
observed in the four smaller planets, or asteroids, whose paths are so
closely interwoven.
The eccentriciities of Juno and Pallas are very nearly identical, and reach
three times as great as those of Ceres and Vesta. The same may be said of
the inclination of the orbits of the planets toward the plane of projection
of the ecliptic, or in the position of their axes of rotation with relation
to their orbits, a position on which the relations of climate, seasons of
the year, and length of the days depend more than on eccentricity. Those
planets that have the most elongated elliptic orbits, as Juno, Pallas, and
Mercury, have also, although not to the same degree their orbits most
strongly inclined toward the ecliptic. Pallas has a comet-like inclination
nearly twenty-six times greater than that of Jupiter, while in the little
planet Vesta, which is so near Pallas, the angle of inclination scarcely by
six times exceeds that of Jupiter. An equally irregular succession is
observed in the position of the axes of the few planets (four or five) whose
planes of rotation we know with any degree of certainty. It would appear
from the position of the satellites of Uranus, two of which, the second and
fourth, have been recently observed with certainty, that the axis of this,
the outermost of all the planets is scarcely inclined as much as 11 degrees
toward the plane of its orbit, while Saturn is placed between this planet,
whose axis almost coincides with the plane of its orbit, and Jupiter, whose
axis of rotation is nearly perpendicular to it.
In this enumeration of the forms which compose the world in space, we have
delineated them as possessing an actual existence, and not as objects of
intellectual contemplation, or as mere links of a mental and causal chain of
connection. The planetary system, in its relations of absolute size and
relative position of the axes, density, time of rotation, and different
degrees of eccentricity of the orbits, does not appear to offer to our
apprehension any stronger evidence of a natural necessity than the
proportion observed in the distribution of land and water on the Earth, the
configuration of continents, or the height of mountain chains. In these
respects we can discover no common law in the regions of space or in the
inequalities of the earth's crust. They are 'facts' in nature that have
arisen from the conflict of manifold forces acting under unknown
p 95
conditions, although man considers as 'accidental' whatever he is unable to
explain in the planetary formation on purely genetic principles. If the
planets have been formed out of separate rings of vaporous matter revolving
round the Sun, we may conjecture that the different thickness, unequal
density, temperature, and electro-magnetic tension of these rings may have
given occasion to the most various agglomerations of matter, in the same
manner as the amount of tangential velocity and small variations in its
direction have produced so great a differencein the forms and inclinations
of the elliptic orbits. Attractions of mass and laws of gravitation have no
doubt exercised an influence here, no less than in the geognostic relations
of the elevations of continents; but we are unable from the present forms to
draw any conclusions regarding the series of conditions through which they
have passed. Even the so-called law of the distances of the planets from
the Sun, the law of progression (which led Kepler to conjecture the
existence of a planet supplying the link that was wanting in the chain of
connection between Mars and Jupiter), has been found numerically inexact for
the distances between Mercury, Venus, and the Earth, and a variance with the
conception of a series, owing to the necessity for a supposition in the case
of the first member.
The hitherto disscovered principal planets that revolve round our Sun are
attended certainly by fourteen, and probably by eighteen secondary planets
(moons or satellites). The principal planets are, therefore, themselves the
central bodies of subordinate systems. We seem to recognize in the fabric
of the universe the same process of arrangement so frequently exhibited in
the development of organic life, where we find in the manifold combinations
of groups of plants or animals the same typical form repeated in the
'subordinate classes'. The secondary planets or satellites are more
frequent in the external region of the planetary system, lying beyond the
intersecting orbits of the smaller planets or asteroids; in the inner region
none of the planets are attended by satellites, with the exception of the
Earth, whose moon is relatively of great magnitude, since its diameter is
equal to a fourth of that of the Earth, while the diameter of the largest of
all known secondary planets -- the sixth satellite of Saturn -- is probably
about one seventeenth, and the largest of Jupiter's moons, the third, only
about one twenty-sixth part that of the primary planet or central body. The
planets which are attended by the largest number of satellites are most
remote from the Sun,
p 96
and are at the same time the largest, most compressed at the poles, and the
least dense. According to the most recent measurements of MÂdler, Uranus
has a greater planetary compression than any other of the planets, viz.,
1/9.92d. In our Earth and her moon, whose mean distance from one another
amounts to 207,200 miles, we find that the differences of mass* and diameter
between the two are much less considerable than are usually observed to
exist between the principal planets and their attendant satellites, or
between bodies of different orders in the solar system.
[footnote] *If, according to Burckhardt's determination, the Moon's radius
be 0.2725 and its volume 1/49.00th, its density will be 0.5596, or nearly
five ninths. Compare, also, Wilh. Beer and H. Madler, 'der Mond', 2, 10,
and Madler, 'Ast.', 157. The material contents of the Moon are, according
to Hansen, nearly 1/34th (and Âdler 1/40.6th) that of the Earth, and its
mass equal to 1/87.73d that of the Earth. In the largest of Jupiter's
moons, the third, the relations of volume to the central body are 1/15370th,
and of mass 1/11300th. On the polar flattening of Uranus, see Schum,
'Astron. Nachr.', 1844, No. 493.
While the density of the Moon is five ninths less than that of the Earth, it
would appear, if we may sufficiently depend upon the determinations of their
magnitudes and masses, that the second of Jupiter's moons is actually denser
than that great planet itself. Among the fourteen satellites that have been
investigated with any degree of certainty, the system of the seven
satellites of Saturn presents an instance of the greatest possible contrast,
both in absolute magnitude and in distance from the central body. The sixth
of these satellites is probably not much smaller than Mars, while our moon
has a diameter which does not amount to more than half that of the latter
planet. With respect to volume, the two outer, the sixth and seventh of
Saturn's satellites, approach the nearest to the third and brightest of
Jupiter's moons. The two innermost of these satellites belong perhaps,
together with the remote moons of Uranus to the smallest cosmical bodies of
our solar system, being only made visible under favorable circumstances by
the most powerful instruments. They were first discovered by the forty-foot
telescope of William Herschel in 1789, and were seen again by John Herschel
at the Cape of Good Hope, by Vico at Rome, and by Lamont at Munich.
Determinations of the 'true' diameter of satellites, made by the measurement
of the apparent size of their small disks, are subjected to many optical
difficulties; but numerical astronomy, whose task it is to predetermine by
calculation the motions of the heavenly bodies as they will appear when
viewed from the Earth, is directed almost
p 97
exclusively to motion and mass, and but little to volume. The absolute
distance of a satellite from its central body is greatest in the case of the
outermost or seventh satellite of Saturn, its distance from the body round
which it revolves amounting to more than two millions of miles, or ten times
as great a distance as that of our moon from the Earth. In the case of
Jupiter we find that the outermost or fourth attendant moon is only
1,040,000 miles from that planet, while the distance between Uranus and its
sixth satellite (if the latter really exist) amounts to as much as 1,360,000
miles. If we compare, in each of these subordinate systems, the volume of
the satellite, we discover the existence of entirely new numerical
relations. The distances of the outermost satellites of Uranus, Saturn, and
Jupiter are when expressed in semi-diameters of the main planets, as 91, 64,
and 27. The outermost satellite of Saturn appears, therefore, to be removed
only about one fifteenth further from the center of that planet than our
moon is from the Earth. The first or innermost of Saturn's satellites is
nearer to its central body than any other of the secondary planets, and
presents, moreover, the only instance of a period of revolution of less than
twenty-four hours. Its distance from the center of Saturn may, according to
MÂdler and Wilhelm Beer, be expressed as 2.47 semi-diameters of that
planet, or as 80,088 miles. Its distance from the surface of the main
planet is therefore 47,480 miles, and from the outer-most edge of the ring
only 4916 miles. The traveler may form to himself an estimate of the
smallness of this amount by remembering the statement of an enterprising
navigator, Captain Beechey, that he had in three years passed over 72,800
miles. If, instead of absolute distances, we take the semi-diameters of the
principal planets, we shall find that even the first or nearest of the moons
of Jupiter (which is 26,000 miles further removed from the center of that
planet than our moon is from that of the Earth) is only six semi-diameters
of Jupiter from its center, while our moon is removed from us fully 60 1/3d
semi-diameters of the Earth.
In the subordinate systems of satellites, we find that the same laws of
gravitation which regulate the revolutions of the principal planets round
the Sun likewise govern the mutual relations existing between these planets
among one another and with reference to their attendant satellites. The
twelve moons of Saturn, Jupiter, and the Earth all most like the primary
planets from west to east, and in elliptic orbits, deviating
p 98
but little from circles. It is only in the case of one moon, and perhaps in
that of the first and innermost of the satellites of Saturn (0.068), that we
discover an eccentricity greater than that of Jupiter; according to the very
exact observations of Bessel, the eccentricity of the sixth of Saturn's
satellites (0.029) exceeds that of the Earth. On the extremest limits of
the planetary system, where, at a distance nineteen times greater than that
of our Earth, the centripetal force of the Sun is greatly diminished, the
satellites of Uranus (which most striking contrasts from the facts observed
with regard to other secondary planets. Instead, as in all other
satellites, of having their orbits but slightly inclined toward the ecliptic
and (not excepting even Saturn's ring, which may be regarded as a fusion of
agglomerated satellites) moving from west to east, the satellites of Uranus
are almost perpendicular to the ecliptic, and move retrogressively from east
to west, as Sir John Herschel has proved by observations continued during
many years. If the primary and secondary planets have been formed by the
condensation of rotating rings of solar and planetary atmospheric vapor,
there must have existed singular causes of retardation or impediment in the
vaporous rings revolving round Uranus, by which, under the relations with
which we are unacquainted, the revolution of the second and fourth of its
satellites was made to assume a direction opposite to that of the rotation
of the central planet.
It seems highly probable that the period of rotation of 'all' secondary
planets is equal to that of their revolution round the main planet, and
therefore that they always present to the latter the same side.
Inequalities, occasioned by sight variations in the revolution, give rise to
fluctuations of from 6 degrees to 8 degrees, or to an apparent libration in
longitude as well as in latitude. Thus, in the case of our moon, we
sometimes observe more than the half of its surface, the eastern and
northern edges being more visible at one time, and the western or southern
at another. By means of this libration* we are enabled to see the annular
mountain Malapert (which occasionally conceals the Moon's south pole), the
arctic landscape round the crater of Gioja, and the large gray plane near
Endymion which exceeds in superficial extent the 'Mare Vaporum'.
[footnote] *Beer and Madler, op. cit., 185, s.208, and ¤ 347, s. 332; and
ix their 'Phys. Kenntniss der himml. Korper', s. 4 und 69, Tab. 1 (Physical
History of the Heavenly Bodies).
Three sevenths of the Moon's surface are entirely
p 99
concealed from our observation, and must always remain so, unless new and
unexpected disturbing causes come into play. These cosmical relations
involuntarily remind us of nearly similar conditions in the intellectual
world, where, in the domain of deep research into the mysteries and the
primeval creative forces of nature, there are regions similarly turned away
from us, and apparently unattainable, of which only a narrow margin has
revealed itself, for thousands of years, to the human mind, appearing, from
time to time, either glimmering in true or delusive light. We have hitherto
considered the primary planets, their satellites, and the concentric rings
which belong to one, at least, of the outermost planets, as products of
tangential force, and as closely connected together by mutual attraction; it
therefore now only remains for us to speak of the unnumbered host of
'comets' which constitute a portion of the cosmical bodies revolving in
independent orbits round the Sun. If we assume an equable distribution of
their orbits, and the limits of their perihelia, or greatest proximities to
the Sun, and the possibility of their remaining invisible to the inhabitants
of the Earth, and base our estimates on the rules of the calculus of
probabilities, we shall obtain as the result an amount of myriads perfectly
astonishing. Kepler, with his usual animation of expression, said that
there were more comets in the regions of space than fishes in the depths of
the ocean. As yet, however, there are scarcely one hundred and fifty whose
paths have been calculated, if we may assume at six or seven hundred the
number of comets whose appearance and passage through known constellations
have been ascertained by more or less precise observations. While the
so-called classical nations of the West, the Greeks and Romans, although
they may occasionally have indicated the position in which a comet first
appeared, never afford any information regarding its apparent path, the
copious literature of the Chinese (who observed nature carefully, and
recorded with accuracy what they saw) contains circumstantial notices of the
constellations through which each comet was observed to pass. These notices
go back to more than five hundred years before the Christian era, and many
of them are still found to be of value in astronomical observations.*
[footnote] *The first comets of whose orbits we have any knowledge, and
which were calculated from Chinese observations, are those of 240 (under
Gordian II.), 539 (under Justinian), 565, 568, 574, 837, 1337, and 1385.
See John Russell Hind, in Schum., 'Astron. Nachr.', 1843, No. 498. While
the comet of 837 (which, according to Du Sejour, continued during
twenty-four hours within a distance of 2,000,000 miles from the Earth)
terrified Louis I. of France to that degree that he busied himself in
building churches and founding monastic establishments, in the hope of
appeasing the evils threatened by its appearance, the Chinese astronomers
made observations on the path of this cosmical body, whose tail extended
over a space of 60 degrees, appearing sometimes single and sometimes
multiple. The first comet that has been calculated solely from European
observations was that of 1456, known as Halley's comet, from the belief
long, but erroneously, entertained that the period when it was first
observed by that astronomer was its first and only well-attested appearance.
See Arago, in the 'Annuaire', 1836, p. 204, and Langier, 'Comptes Rendus
des Seances de l'Acad.', 1843, t. xvi., 1006.
p 100
Although comets have a smaller mass than any other cosmical bodies -- being,
according to our present knowledge, probably not equal to 1/5000th part of
the Earth's mass -- yet they occupy the largest space, as their tails in
several instances extend over many millions of miles. The cone of luminous
vapor which radiates from them has been found, in some cases (as in 1680 and
1811), to equal the length of the Earth's distance from the Sun, forming a
line that intersects both the orbits of Venus and Mercury. It is even
probable that the vapor of the tails of comets mingled with our atmosphere
in the years 1819 and 1823.
Comets exhibit such diversities of form, which appear rather to appertain to
the individual than the class, that a description of one of these "wandering
light-clouds," as they were already called by Xenophanes and Theon of
Alexandria, contemporaries of Pappus, can only be applied with caution to
another. The faintest telescopic comets are generally devoid of visible
tails, and resemble Herschel's nebulous stars. They appear like circular
nebulae of faintly-glimmering vapor, with the light concentrted toward the
middle. This is the most simple type; but it can not, however, be regarded
as rudimentary, since it might equally be the type of an older cosmical
body, exhausted by exhalation. In the larger comets we may distinguish both
the so-called "head" or "nucleus," and the single or multiple tail, which is
characteristically denominated by the Chinese astronomers "the brush"
('sui'). The nucleus generally presents no definite outline, although, in a
few rare cases, it appears like a star of the first or second magnitude, and
has even been seen in bright sunshine;* as,
p 101
for instance, in the large comets of 1402, 1532, 1577, 1744, and 1843.
[footnote] *Arago, 'Annuaire', 1832, p. 209, 211. The phenomenon of the
tail of a comet being visible in bright sunshine, which is recorded of the
comet of 1402, occurred again in the case of the large comet of 1843, whose
nucleus and tail were seen in North America on the 28th of February
(according to the testimony of J. G. Clarke, of Portland, state of Maine),
between 1 and 3 o'clock in the afternoon.(a) The distance of the very dense
nucleus from the sun's light admitted of being measured with much exactness.
The nucleus and tail appeared like a very pure white cloud, a darker space
intervening between the tail and the nucleus. ('Amer. Journ. of Science',
vol. xiv., No. 1, p. 229.)
[footnote] (a) [The translator was at New Bedford, Massachusetts, U.S., on
the 28th February, 1843, and distinctly saw the comet, between 1 and 2 in
the afternoon. The sky at the time was intensely blue, and the sun shining
with a dazzling brightness unknown in European climates.] -- Tr
This latter circumstance indicates, in particular individuals, a denser
mass, capable of reflecting light with greater intensity. Even in
Herschel's large telescope, only two comets, that discovered in Sicily in
1807, and the splendid one of 1811, exhibited well-defined disks;* the one
at an angle of 1 second, and the other at 0.77 seconds, whence the true
diameters are assumed to be 536 and 428 miles.
[footnote] *'Phil. Trans.' for 1808, Part ii., p. 155, and for 1812, Part
i., p. 118. The diameters found by Herschel for the nuclei were 538 and 428
English miles. For the magnitudes of the comets of 1798 and 1805, see
Arago, 'Annuaire', 1832, p. 203.
The diameters of the less well-defined nuclei of the comets of 1798 and 1805
did not appear to exceed 24 or 28 miles.
In several comets that have been investigated with great care, especially in
the above-named one of 1811, which continued visible for so long a period,
the nucleus and its nebulous envelope were entirely separated from the tail
by a darker space. The intensity of light in the nucleus of comets does not
augment toward the center in any uniform degree, brightly shining zones
being in many cases separated by concentric nebulous envelopes. The tails
sometimes appear single, sometimes, although more rarely, double; and in the
comets of 1807 and 1843 the branches were of different lengths; in one
instance (1744) the tail had six branches, the whole forming an angle of 60
degrees. The tails have been sometimes straight, sometimes curved, either
toward both sides, or toward the side appearing to us as the exterior (as in
1811), or convex toward the direction in which the comet is moving (as in
that of 1618); and sometimes the tail has even appeared like a flame in
motion. The tails are always turned away from the sun, so that their line
of prolongation passes through its center; a fact which, according to Edward
Biot, was noticed by the Chinese astronomers as early as 837, but was first
generally made known in Europe by Fracastoro and Peter Apian in the
sixteenth century. These emanations may be regarded as conoidal envelopes
of greater of less thickness,
p 102
and, considered in this manner, they furnish a simple explanation of many of
the remarkable optical phenomena already spoken of.
Comets are not only characteristically different in form, some being
entirely without a visible tail, while others have a tail of immense length
(as in the instance of the comet of 1618, whose tail measured 104 degrees),
but we also see the same comets undergoing successive and rapidly-changing
processes of configuration. These variations of form have been most
accurately and admirably described in the comet of 1744, by Hensius, at St.
Petersburg, and in Halley's comet, on its last reappearance in 1835, by
Bessel, at Konigsberg. A more or less well-defined tuft of rays emanated
from that part of the nucleus which was turned toward the Sun; and the rays
being bent backward, formed a part of the tail. The nucleus of Halley's
comet; with its emanations, presented the appearance of a burning rocket,
the end of which was turned sideways by the force of the wind. The rays
issuing from the head were seen by Arago and myself, at the Observatory at
Paris, to assume very different forms on successive nights.*
[footnote] *Arago, 'Des Changements physiques de la Comete de Halley du
15-23 Oct., 1835. 'Annuaire', 1836, p. 218, 221. The ordinary direction of
the emanations was noticed even in Nero's time. "Comae radios solis
effugiunt." -- Seneca, 'Nat. Quaest.', vii., 20.
The great Konigsberg astronomer concluded from many measurements, and from
theoretical considerations, "that the cone of light issuing from the comet
deviated considerably both to the right and the left of the true direction
of the Sun, but that it always returned to that direction, and passed over
to the opposite side, so that both the cone of light and the body of the
comet from whence it emanated experienced a rotatory, or, rather, a
vibratory motion in the plane of the orbit." He finds that "the attractive
force exercised by the Sun on heavy bodies is inadequate to explain such
vibrations, and is of opinion that they indicate a polar force, which turns
one semi-diameter of the comet toward the Sun, and strives to turn the
opposite side away from that luminary. The magnetic polarity possessed by
the Earth may present some analogy to this, and, should the Sun have an
opposite polarity, an influence might be manifested, resulting in the
precession of the equinoxes." This is not the place to enter more fully
upon the grounds on which explanations of this subject have been based; but
observations so remarkable,* and views of so exalted
p 103
a character, regarding the most wonderful class of the cosmical bodies
belonging to our solar system, ought not to be entirely passed over in this
sketch of a general picture of nature.
[footnote] *Bessel, in Schumacher, 'Astr. Nachr.', 1836, No. 300-302, s.
188, 192, 197, 200, 202, und 230. Also in Schumacher, 'Jahrb.', 1837, s.
149, 168. William Herschel, in his observations on the beautiful comet of
1811, believed that he had discovered evidences of the rotation of the
nucleus and tail ('Phil. Trans.' for 1812, Part i., p. 140). Dunlop, at
Paramatta thought the same with reference to the third comet of 1825.
Although, as a rule, the tails of comets increase in magnitude and
brilliancy in the vicinity of the sun, and are directed away from that
central body, yet the comet of 1823 offered the remarkable example of two
tails, one of which was turned toward the sun, and the other away from it,
forming with each other an angle of 160 degrees. Modifications of polarity
and the unequal manner of its distribution, and of the direction in which it
is conducted, may in this rare instance have occasioned a double, unchecked,
continuous emanation of nebulous matter.*
[footnote] *Bessel, in 'Astr. Nachr.', 1836, No. 302, s. 231. Schum,
'Jahrb.', 1837 s. 175. See, also Lehmann, 'Ueber Cometenschweife' (On the
Tails of Comets), in Bode, 'Astron. Jahrb. fur' 1826, s. 168.
Aristotle, in his 'Natural Philosophy', makes these emanations the means of
bringing the phenomena of comets into a singular connection with the
existence of the Milky Way. According to his views, the innumerable
quantity of stars which compose this starry zone give out a self-luminous,
incandescent matter. The nebulous belt which separates the different
portions of the vault of heaven was therefore regarded by the Stagirite as a
large comet, the substance of which was incessantly being renewed.*
[footnote] *Aristot., 'Meteor.', i., 8, 11-14, und 19-21 (ed. Ideler, t.
i., p. 32-34). Biese, 'Phil. des Aristoteles', bd. ii., s. 86. Since
Aristotle exercised so great an influence throughout the whole of the Middle
Ages, it is very much to be regretted that he was so averse to those grander
views of the elder Pythagoreans, which inculcated ideas so nearly
approximating to truth respecting the structure of the universe. He asserts
that comets are transitory meteors belonging to our atmosphere in the very
book in which he cites the opinion of the Pythagorean school, according to
which these cosmical bodies are supposed to be planets having long periods
of revolution. (Aristot., i., 6, 2.) This Pythagorean doctrine, which,
according to the testimony of Apollonius Myndius, was still more ancient,
having originated with the Chaldeans, passed over to the Romans, who in this
instance, as was their usual practice, were merely the copiers of others.
The Myndian philosopher describes the path of comets as directed toward the
upper and remote regions of heaven. Hence Seneca says, in his 'Nat.
Quaest.', vii., 17: "Cometes non est species falsa, sed proprium sidus
sicut solis et lunae: altiora mundi secat et tunc demum apparet quum in
imum cursum sui venit;" and again (at vii., 27), "Cometes aternos esse et
sortis ejusdem, cujus caetera (sidera), etiamsi faciem illis non habent
similem." Pliny (ii., 25) also refers to Apollonius Myndius, when he says,
"Sunt qui et haec sidera perpetua esse credant suoque ambitu ire, sed non
nisi relicta a sole cerni."
p 104
The occulation of the fixed stars by the nucleus of a comet, or by its
innermost vaporous envelopes, might throw some light on the physical
character of these wonderful bodies; but we are unfortunately deficient in
observations by which we may be assured* that the occulation was perfectly
central; for, as it has already been observed, the parts of the envelope
contiguous to the nucleus are alternately composed of layers of dense or
very attenuated vapor.
[footnote] *Olbers, in 'Astr. Nachr.', 1828, s. 157, 184. Arago, 'De la
Constitution physique des Cometes; Annuaire de' 1832, p. 203, 208. The
ancients were struck by the phenomenon that it was possible to see through
comets as through a flame. The earliest evidence to be met with of stars
having been seen through comets is that of Democritus (Aristot., 'Meteor.',
i., 6, 11), and the statement leads Aristotle to make the not unimportant
remark, that he himself had observed the occulation of one of the stars of
Gemini by Jupiter. Seneca only speaks decidedly of the transparence of the
tail of comets. "We may see," says he, "stars through a comet as through a
cloud ('Nat. Quaest.', vii., 18); but we can ony see through the rays of the
tail, and not through the body of the comet itself: 'non in ea parte qua
sidus ipsum est spissi et solidi ignis, sed qua rarus splendor occurrit et
in crines dispergitur. Per intervalla ignium, non er ipsos, vides" (vii.,
26). The last remark is unnecessary, since, as Galileo observed in the
'Saggiatore (Lettera a Monsignor Cesarini', 1619), we can certainly see
through a flame when it is not of too great a thickness'.
On the other hand the carefully conducted measurements of Bessel prove,
beyond all doubt, that on the 29th of September, 1835, the light of a star
of the tenth magnitude, which was then at a distance of 7".78 from the
central point of the head of Halley's comet, passed through very dense
nebulous matter, without experiencing any deflection during its passage.*
[footnote] *Bessel, in the 'Astron. Nachr.', 1836, No. 301, s. 204, 206.
Struve, in 'Recueil des Mem. de l'Acad. de St. Peterab.', 1836, p. 140, 143,
and 'Astr. Nachr.', 1836, No. 303, s. 238, writes as follows: "At Dorpat
the star was in conjunction only 2".2 from the brightest point of the comet.
The star remained continually visible, and its light was not perceptibly
diminished, while the nucleus of the comet seemed to be almost extinguished
before the radiance of the small star of the ninth or tenth magnitude."
If such an absence of refracting power must be ascribed to the nucleus of a
comet, we can scarcely regard the matter composing comets as a gaseous
fluid. The question here arises whether this absence of refracting power
may not be owing to the extreme tenuity of the fluid; or does the comet
consist of separated particles, constituting a cosmical stratum of clouds,
which, like the clouds of our atmosphere, that exercise no influence on the
p 105
zenith distance of the stars, does not affect the ray of light passing
through it? In the passage of a comet over a star, a more or less
considerable diminution of light has often been observed; but this has been
justly ascribed to the brightness of the ground from which the star seems to
stand forth during the passage of the comet.
The most important and decisive observations that we possess on the nature
and the light of comets are due to Arago's polarization experiments. His
polariscope instructs us regarding the physical constitution of the Sun and
comets, indicating whether a ray that reaches us from a distance of many
millions of miles transmits light directly or by reflection; and if the
former, whther the source of light is a solid, a liquid, or a gaseous body.
His apparatus was used at the Paris Observatory in examining the light of
Capella and that of the great comet of 1819. The latter showed polarized,
and therefore reflected light, while the fixed star, as was to be expected,
appeared to be a self-luminous sun.*
[footnote] *On the 3d of July, 1819, Arago made the first attempt to
analyze the light of comets by polarization, on the evening of the sudden
appearance of the great comet. I was present at the Paris Observatory, and
was fully convinced, as were also Matthieu and the late Bouvard of the
dissimilarity in the intensity of the light seen in the polariscope, when
the instrument received cometary light. When it received light from
Capella, which was near the comet, and at an equal altitude, the images were
of equal intensity. On the reappearance of Halley's comet in 1835, the
instrument was altered so as to give, according to Arago's chromatic
polarization, two images of complementary colors (green and red). ('Annales
de Chimie', t. xiii., p. 108; 'Annuaire', 1832, p. 216.) "We must conclude
from these observations," says Arago, "that the cometary light was not
entirely composed of rays having the properties of direct light, there being
light which was reflected specularly or polarized, that is, coming from the
sun. It can not be stated with absolute certainty that comets shine only
with borrowed light, for bodies, in becoming self-luminous, do not, on that
account, lose the power of reflecting foreign light."
The existance of polarized cometary light announced itself not only by the
inequality of the images, but was proved with greater certainty on the
reappearance of Halley's comet, in the year 1835, by the more striking
contrast of the complementary colors, deduced from the laws of chromatic
polarization discovered by Arago in 1811. These beautiful experiments still
leave it undecided whether, in addition to this reflected solar light,
comets may not have light of their own. Even in the case of the planets,
as, for instance, in Venus, an evolution of independent light seems very
probable.
The variable intensity of light in comets can not always be
p 106
explained by the position of their orbits and their distance from the Sun.
It would seem to indicate, in some individuals, the existence of an inherent
process of condensation, and an increased or diminished capacity of
reflecting borrowed light. In the comet of 1618, and in that which has a
period of three years, it was observed first by Hevelius that the nucleus of
the comet diminished at its perihelion and enlarged at its aphelion, a fact
which, after remaining long unheeded, was again noticed by the talented
astronomer Valz at Nismes. The regularity of the change of volume,
according to the different degrees of distance from the Sun, appears very
striking. The physical explanation of the phenomenon can not, however, be
sought in the condensed layers of cosmical vapor occurring in the vicinity
of the Sun, since it is difficult to imagine the nebulous envelope of the
nucleus of the comet to be vesicular and impervious to the other.*
[footnote] *Arago, in the 'Annuaire', 1832, p. 217-220. Sir John Herschel,
'Astron.', 488.
The dissimilar eccentricity of the orbits of comets has, in recent times
(1819), in the most brilliant manner enriched our knowledge of the solar
system. Encke has discovered the existence of a comet of so short a period
of revolution that it remains entirely within the limits of our planetary
system, attaining its aphelion between the orbits of the smaller planets and
that of Jupiter. Its eccentricity must be assumed at 0.845, that of Juno
(which has the greatest eccentricity of any of the planets) being 0.255.
Encke's comet has several times, although with difficulty, been observed by
the naked eye, as in Europe in 1819, and according to Rumker, in New Holland
in 1822. Its period of revolution is about 3 1/3d years; but, from a
careful comparison of the epochs of its return to its perihelion, the
remarkable fact has been discovered that these periods have diminished in
the most regular manner between the years 1786 and 1838, the diminution
amounting, in the course of 52 years, to about 1 3/10th days. The attempt
to bring into unison the results of observation and calculation in the
investigation of all the planetary disturbances, with the view of explaining
this phenomenon, has led to the adoption of the very probable hypothesis
that there exists dispersed in space a vaporous substance capable of acting
as a resisting medium. This matter diminished the tangential force, and
with it the major axis of the comet's orbit. The value of the constant of
the resistance appears to be somewhat different before and after the
perihelion; and this may, perhaps, be ascribed
p 107
to the altered form of the small nebulous star in the vicinity of the Sun,
and to the action of the unequal density of the strata of cosmical ether.*
[footnote] *Encke, in the 'Astronomiche Nachrichten', 1843, No. 489, s.
130-132.
These facts, and the investigations to which they have led, belong to the
most interesting results of modern astronomy. Encke's comet has been the
means of leading astronomers to a more exact investigation of Jupiter's mass
(a most important point with reference to the calculation of perturbations);
and, more recently, the course of this comet has obtained for us the first
determination, although only an approximative one, of a smaller mass for
Mercury.
The discovery of Encke's comet, which had a period of only 3 1/3d years, was
speedily followed, in 1826, by that of another, Biela's comet, whose period
of revolution is 6 3/4th years, and which is likewise planetary, having its
aphelion beyond the orbit of Jupiter, but within that of Saturn. It has a
fainter light than Encke's comet, and, like the latter, its motion is
direct, while Halley's comet moves in a course opposite to that pursued by
the planets. Biela's comet presents the first certain example of the orbit
of a comet intersecting that of the Earth. This position, with reference to
our planet, may therefore be productive of danger, if we can associate an
idea of danger with so extraordinary a natural phenomenon, whose history
presents no parallel, and the results of which we are consequently unable
correctly to estimate. Small masses endowed with enormous velocity may
certainly exercise a considerable power; but Laplace has shown that the mass
of the comet of 1770 is probably not equal to 1/5000th that of the Earth, or
about 1/2000th that of the Moon.*
[footnote] *Laplace, 'Expos. du Syst. du Monde', p. 216, 237.
We must not confound the passage of Biela's comet through the Earth's orbit
with its proximity to, or collision with our globe. When this passage took
place, on the 29th of October, 1832, it required a full month before the
Earth would reach the point of intersection of the two orbits. These two
comets of short periods of revolution also intersect each other, and it has
been justly observed,* that amid the many perturbations experienced by such
small bodies from the largr planets, there is a 'possibility' -- supposing a
meeting of these comets to occur in October -- that the inhabitants of the
Earth may witness the extraordinary spectacle of an encounter between two
cosmical bodies, and possibly of their reciprocal penetration and
amalgamation, or of their destruction by means of exhausting emanations.
[footnote] *Littrow, 'Beschreibende Astron.', 1835, s. 274. On the inner
comet recently discovered by M. Faye, at the Observatory of Paris, and whose
eccentricity is 0.551, its distance at its perihelion 1.690, and its
distance at its aphelion 5.832, see Schumacher, 'Astron. Nachr.', 1844, No.
495. Regarding the supposed identity of the comet of 1766 with the third
comet of 1819, see 'Astr. Nachr.', 1833, No. 239; and on the identity of the
comet of 1743 and the fourth comet of 1819, see No. 237 or the last
mentioned work.
Events of this nature, resulting either from deflection occasioned by
disturbing masses or primevally intersecting orbits, must have been of
frequent occurrence in the course of millions of years in the immeasurable
regions of ethereal space; but they must be regarded as isolated
occurrences, exercising no more general or alternative effects on cosmical
relations than the breaking forth or extinction of a volcano within the
limited sphere of our Earth.
A third interior comet, having likewise a short period of revolution was
discovered by Faye on the 22d of November, 1843, at the Observatory at
Paris. Its elliptic path, which approaches much more nearly to a circle
than that of any other known comet, is included within the orbits of Mars
and Saturn. This comet, therefore, which, according to Goldschmidt, passes
beyond the orbit of Jupiter, is one of the few whose perihelia are beyond
Mars. Its period of revolution is 7 29/100 years, and it is not improbable
that the form of its present orbit may be owing to its great approximation
to Jupiter at the close of the year 1839.
If we consider the comets in their inclosed elliptic orbits as members of
our solar system, and with respect to the length of their major axes, the
amount of their eccentricity, and their periods of revolution, we shall
probably find that the three planetary comets of Encke, Biela, and Faye are
most nearly approached in these respects, first, by the comet discovered in
1766 by Messier, and which is regarded by Clausen as identical with the
third comet of 1819; and next, by the fourth comet of the last-mentioned
year, discovered by Blaupain, but considered by Clausen as identical with
that of the year 1743, and whose orbit appears, like that of Lexell's comet,
to have suffered great variations from the proximity and attraction of
Jupiter. The two last-named comets would likewise seem to have a period of
revolution not exceeding five or six years, and their aphelia are in the
vicinity of Jupiter's orbit. Among the comets that have a period of
revolution of from seventy to
p 109
seventy-six years, the first in point of importance with respect to
theoretical and physical astronomy is Halley's comet, whose last appearance,
in 1835, was much less brilliant than was to be expected from preceding
ones; next we would notice Olbers's comet, discovered on the 6th of March,
1815; and, lastly, the comet discovered by Pons in the year 1812, and whose
elliptic orbit has been determined by Encke. The two latter comets were
invisible to the naked eye. We now know with certainty of nine returns of
Halley's large comet, it having recently been proved by Laugier's
calculations*, that in the Chinese table of comets, first made known to us
by Edward Biot, the comet of 1378 is identical with Halley's; its periods of
revolution have varied in the interval between 1378 and 1835 from 74.91 to
77.58 years, the mean being 76.1.
[footnote] *Laugier, in the 'Comptes Rendus des Seances de l'Academie',
1843, t. xvi., p. 1006.
A host of other comets may be contrasted with the cosmical bodies of which
we have spoken, requiring several thousand years to perform their orbits,
which it is difficult to determine with any degree of certainty. The
beautiful comet of 1811 requires, according to Argelander, a period of 3065
years for its revolution, and the colossal one of 1680 as much as 8800
years, according to Encke's calculation. These bodies respectively recede,
therefore, 21 and 44 times further than Uranus from the Sun, that is to say,
33,600 and 70,400 millions of miles. At this enormous distance the
attractive force of the Sun is still manifested; but while the velocity of
the comet of 1680 at its perihelion is 212 miles in a second, that is,
thirteen times greater than that of the Earth, it scarcely moves ten feet in
the second when at its aphelion. This velocity is only three times greater
than that of water in our most sluggish European rivers, and equal only to
half that which I have observed in the Cassiquiare, a branch of the Orinoco.
It is highly probable that, among the innumerable host of uncalculated or
undiscovered comets, there are many whose major axes greatly exceed that of
the comet of 1680. In order to form some idea by numbers, I do not say of
the sphere of attraction, but of the distance in space of a fixed star, or
other sun, from the aphelion of the comet of 1680 (the furthest receding
cosmical body with which we are acquainted in our solar system), it must be
remembered that, according to the most recent determinations of parallaxes,
the nearest fixed star is full 250 times further removed from our sun than
the comet in its aphelion. The comet's distance is only 44
p 110
times that of Uranus, while 'a' Centauri is 11,000 and 61 Cygni 31,000 times
that of Uranus, according to Bessel's determinations.
Having considered the greatest distances of comets from the central body, it
now remains for us to notice instances of the greatest proximity hitherto
measured. Lexell and Burckhardt's comet of 1770, so celebrated on account
of the disturbances it experienced from Jupiter, has approached the Earth
within a smaller distance than any other comet. On the 28th of June, 1770,
its distance from the Earth was ony six times than of the Moon. The same
comet passed twice, viz., in 1769 and 1779, through the system of Jupiter's
four satellites without producing the slightest notable change in the
well-known orbits of these bodies. The great comet of 1680 approached at
its perihelion eight or nine times nearer to the surface of the Sun than
Lexell's comet did to that of our Earth, being on the 17th of December a
sixth part of the Sun's diameter, or seven tenths of the distance of the
Moon from that luminary. Perihelia occurring beyond the orbit of Mars can
seldom be observed by the inhabitants of the Earth, owing to the faintness
of the light of distant comets; and among those already calculated the comet
of 1729 is the only one which has its perihelion between the orbits of
Pallas and Jupiter; it was even observed beyond the latter.
Since scientific knowledge, although frequently blended with vague and
superficial views, has been more extensively diffused through wider circles
of social life, apprehensions of the possible evils threatened by comets
have acquired more weight as their direction has become more definite. The
certainty that there are within the known planetary orbits comets which
revisit our regions of space at short intervals -- that great disturbances
have been produced by Jupiter and Saturn in their orbits, by which such as
were apparently harmless have been converted into dangerous bodies -- the
intersection of the Earth's orbit by Biela's comet -- the cosmical vapor,
which, acting as a resisting and impeding medium, tends to contract all
orbits -- the individual difference of comets, which would seem to indicate
considerable decreasing gradations in the quantity of the mass of the
nucleus, are all considerations more than equivalent, both as to number and
variety, to the vague fears entertained in early ages of the general
conflagration of the world by 'flaming swords', and stars with 'fiery
streaming hair'. As the consolatory considerations which may be derived
from the calculus of probabilities address themselves to reason and to
p 111
meditative understanding only, and not to the imagination or to a desponding
condition of mind, modern science has been accused, and not entirely without
reason, of not attempting to allay apprehensions which it has been the very
means of exciting. It is an inherent attribute of the human mind to
experience fear, and not hope or joy, at the aspect of that which is
unexpected and extraordinary.*
[footnote] *Fries, 'Vorlesungen uber die Sternkunde', 1833, s. 262-267
(Lectures on the Science of Astronomy). An infelicitously chosen instance
of the good omen of a comet may be found in Seneca, 'Nat. Quest.', vii., 17
and 21. The philosopher thus writes of the comet: "Quem nos Neronis
principatu latissimo vidimus et qui cometis detraxit infamiam."
The strange form of a large comet, its faint nebulous light, and its sudden
appearance in the vault of heaven, have in all regions been almost
invariably regarded by the people at large as some new and formidable agent
inimical to the existing state of things. The sudden occurrence and short
duration of the phenomenon lead to the belief of some equally rapid
reflection of its agency in terrestrial matters, whose varied nature renders
it easy to find events that may be regarded as the fulfillment of the evil
foretold by the appearance of these mysterious cosmical bodies. In our own
day, however, the public mind has taken another and more cheerful, although
singular, turn with regard to comets; and in the German vineyards in the
beautiful valleys of the Rhine and Moselle, a belief has arisen, ascribing
to these once ill-omened bodies a beneficial influence on the ripening of
the vine. The evidence yielded by experience, of which there is no lack in
these days, when comets may so frequently be observed, has not been able to
shake the common belief in the meteorological myth of the existence of
wandering stars capable of radiating heat.
This material taken from pages 111- 147
COSMOS: A Sketch of the Physical Description of the Universe, Vol. 1
by Alexander von Humboldt
Translated by E C Otte
from the 1858 Harper & Brothers edition of Cosmos, volume 1
--------------------------------------------------
From comets I would pass to the consideration of a far more enigmatical
class of agglomerated matter -- the smallest of all asteroids, to which we
apply the name 'aÂrolites', or 'meteoric stones',* when they reach our
atmosphere in a fragmentary condition.
[footnote] * (Much valuable information may be obtained regarding the
origin and composition of aÂrolites or meteoric stones in Memoirs on the
subject, by Baumbeer and other writers, in the numbers of Poggendorf's
'Annalen', from 1845 to the present time.) -- Tr.
If I should seem to dwell on the specific enumeration of these bodies, and
of comets, longer than the general nature of this work might warrant, I have
not done so undesignedly. The diversity existing in the individual
characteristics of comets has already been noticed. The imperfect knowledge
we possess of their physical character renders it
p 112
diifficult in a work like the present, to give the proper degree of
circumstantiality to the phenomena, which, although of frequent recurrence,
have been observed with such various degrees of accuracy, or to separate the
necessary from the accidental. It is only with respect to measurements and
computations that the astronomy of comets has made any marked advancement,
and, consequently, a scientific consideration of these bodies must be
limited to a specification of the differences of physiognomy and
conformation in the nucleus and tail, the instances of great approximation
to other cosmical bodies, and of the extremes in the length of their orbits
and in their periods of revolution. A faithful delineation of these
phenomena, as well as of those which we proceed to consider, can only be
given by sketching individual features with the animated circumstantiality
of reality.
Shooting stars, fire-balls, and meteoric stones are, with great probability,
regarded as small bodies moving with planetary velocity, and revolving in
obedience to the laws of general gravity in conic sections round the Sun.
When these masses meet the Earth in their course, and are attracted by it,
they enter within the limits of our atmosphere in a luminous condition, and
frequently let fall more or less strongly heated stony fragments, covered
with a shining black crust. When we enter into a careful investigation of
the facts observed at those epochs when showers of shooting stars fell
periodically in Cumana in 1799, and in North America during the years 1833
and 1834, we shall find that 'fire-balls' can not be considered separately
from shooting stars. Both these phenomena are frequently not only
simultaneous and blended together, but they likewise are often found to
merge into one another, the one phenomenon gradually assuming the character
of the other alike with respect to the size of their disks, the emanation of
sparks, and the velocities of their motion. Although exploding smoking
luminous fire-balls are sometimes seen, even in the brightness of tropical
daylight,* equaling in size the apparent
p 113
diameter of the Moon, innumerable quantities of shooting stars have, on the
other hand, been observed to fall in forms of such extremely small
dimensions that they appear only as moving points or 'phosphorescent
lines.'**
[footnote] *A friend of mine, much accustomed to exact trigonometrical
measurements, was in the year 1788 at Popayan, a city which is 2 degrees 26'
north latitude, lying at an elevation of 5583 feet above the level of the
sea, and at noon, when the sun was shining brightly in a cloudless sky, saw
his room lighted up by a fire-ball. He had his back to the window at the
time, and on turning round, perceived that great part of the path traversed
by the fire-ball was still illuminated by the brightest radiance. Different
nations have had the most various terms to express these phenomena: The
Germans use the word 'Sternschnuppe', literally 'star snuff' -- an
expression well suited to the physical views of the vulgar in former times,
according to which, the lights in the firmament were said to undergo a
process of 'snuffing' or cleaning; and other nations generally adopt a term
expressive of a 'shot' or 'fall' of stars, as the Swedish 'stjernifall', the
Italian 'stella cadente', and the English 'star shoot.' In the woody
district of the Orinoco, on the dreary banks of the Cassiquiare, I heard the
natives in the Mission of Vasiva use terms still more inelegant than the
German 'star snuff.' ('Relation Historique du Voy. aux RÂgions Equinox.',
t. ii., p. 513.) These same tribes term the pearly drops of dew which cover
the beautiful leaves of the heliconia 'star spit.' In the Lithuanian
mythology, the imagination of the people has embodied its ideas of the
nature and signification of falling stars under nobler and more graceful
symbols. The Parc¾, 'Werpeja', weave in heaven for the new-born child its
thread of fate, attaching each separate thread to a star. When death
approaches the person, the thread is rent, and the star wanes and sinks to
the earth. Jacob Grimm, 'Deutsche Mythologie', 1843, s. 685.
[footnote] ** According to the testimony of Professor Denison Olmsted, of
Yale College, New Haven, Connecticut. (See Poggend., 'Annalen der Physik',
bd. xxx., s. 194.) Kepler, who excluded fire-balls and shooting stars from
the domain of astronomy, because they were, according to his views, "meteors
arising from the exhalations of the earth, and blending with the higher
ether," expresses himself, however, generally with much caution. He says:
"Stell¾ cadentes sunt materia viscida inflammata. Earum aliqu¾ inter
cadendum absumuntur, aliqu¾ ver in terram cadunt, pondere suo tract¾.
Nec est dissimile vero, quasdam conglobatas esse ex materia f¾culentÂ, in
ipsam auram ¾theream immixta: exque aÂtheris regione, tractu rectilineo,
per aÂrem trajicere, ceu minutos competas, occult causa motus
utrorumque." -- Kepler, 'Epit. Astron. Copernican¾', t. i., p. 80.
It still remains undertermined whether the many luminous bodies that shoot
across the sky may not vary in their nature. On my return from the
equinoctial zones, I was impressed with an idea that in the torrid regions
of the tropics I had more frequently than in our colder latitudes seen
shooting stars fall as if from a height of twelve or fifteen thousand feet;
that they were of brighter colors, and left a more brilliant line of light
in their track; but this impression was no doubt owing to the greater
transparency of the tropical atmosphere*, which enables the eye to penetrate
further into distance.
[footnote] *'Relation Historique', t. i., p. 80, 213, 527. If in falling
stars, as in comets, we distinguish between the head or nucleus and the
tail, we shall find that the greater transparency of the atmosphere in
tropical climates is evinced in the greater length and brilliancy of the
tail which may be observed in those latitudes. The phenomenon is therefore
not necessarily more frequent there, because it is oftener seen and
continues longer visible. The influence exercised on shooting stars by the
character of the atmosphere is shown occasionally even in our temperate
zone, and at very small distances apart. Wartmann relates that on the
occasion of a November phenomenon at two places lying very near each other,
Geneva and Aux Planchettes, the number of the meteors counted were as 1 to
7. (Wartmann, 'MÂm. sur les Etoiles filantes', p. 17.) The tail of a
shooting star (or its 'train'), on the subject of which Brandes has made so
many exact and delicate observations, is in no way to be ascribed to the
continuance of the impression produced by light on the retina. It sometimes
continues visible a whole minute, and in some rare instances longer than the
light of the nucleus of the shooting star; in which case the luminous track
remains motionless. (Gilb., 'Ann.', bd. xiv., s. 251.) This circumstance
further indicates the analogy between large shooting stars and fire-balls.
Admiral Krusenstern saw, in his voyage round the world, the train of a
fire-ball shine for an hour after the lluminous body itself had disappeared,
and scarcely move throughout the whole time. ('Reise', th. i., s. 58.) Sir
Alexander Burnes gives a charming description of the transparency of the
clear atmosphere of Bokhara, which was once so favorable to the pursuit of
astronomical observations. Bokhara is situated in 39 degrees 48' north
latitude, and at an elevation of 1280 feet above the level of the sea.
"There is a constant serenity in its atmosphere, and an admirable clearness
in the sky. At night, the stars have uncommon luster, and the Milky Way
shines gloriously in the firmament. There is also a never-ceasing display
of the most brilliant meteors, which dart like rockets in the sky; ten or
twelve of them are sometimes seen in an hour, assuming every color -- fiery
red, blue, pale, and faint. It is a noble country for astronomical science,
and great must have been the advantage enjoyed by the famed observatory of
Samarkand." (Burnes, 'Travels into Bokhara', vol. ii. (1834), p. 158.) A
mere traveler must not be reproached for calling ten or twelve shooting
stars in an hour "many," since it is only recently that we have learned,
from careful observations on this subject in Europe, that eight is the mean
number which may be seen in an hour in the field of vision of one individual
(Quetelet, 'Corresp. MathÂm.', Novem., 1837, p. 447); this number is,
however, limited to five or six by that diligent observer, Olbers. (Schum.,
'Jahrb.', 1838, s. 325.)
p 114
Sir Alexander Burnes likewise extols as a consequence of the purity of the
atmosphere in Bokhara the enchanting and constantly-recurring spectacle of
variously-colored shooting stars.
The connection of meteoric stones with the grander phenomenon of fire-balls
-- the former being known to be projected from the latter with such force as
to penetrate from ten to fifteen feet into the earth -- has been proved,
among many other instances, in the falls of azzzuerolites at Barbotan, in
the Department des Landes (24th July, 1790), at Siena (16th June, 1794), at
Weston, in Connecticut, U. S. (14th December, 1807), and at Juvenas in the
Department of ArdÂche (14th June, 1821). Meteoric stones are in some
instances thrown from dark clouds suddenly formed in a clear sky, and fall
with a noise resembling thunder. Whole districts have thus occasionally
been covered with thousands of fragmentary masses, of uniform character but
unequal magnitudes, that
p 115
have been hurled from one of these moving clouds. In less frequent cases,
as in that which occurred on the 16th of September, 1843, at Kleinwenden,
near MÂhilhausen, a large aÂrolite fell with a thundering crash while the
sky was clear and cloudless. The intimate affinity between fire-balls and
shooting stars is further proved by the fact that fire-balls, from which
meteoric stones have been thrown have occasionally been found, as at Angers,
on the 9th of June, 1822, having a diameter scarcely equal to that of the
small fire-works called Roman candles.
The formative power, and the nature of the physical and chemical processes
involved in these phenomena are questions all equally shrouded in mystery,
and we are as yet ignorant whether the particles composing the dense mass of
meteoric stones are originally, as in comets, separated from one another
when they become luminous to our sight, or whether in the case of smaller
shooting stars, any compace substance actually falls, or, finally, whether a
meteor is composed only of a smoke-like dust, containing iron and nickel;
while we are wholly ignorant of what takes place within the dark cloud from
which a noise like thunder is often heard for many minutes before the stones
fall.*
[footnote] *On 'mÂteoric dust', see Arago, in the 'Annuaire' for 1832, p.
254. I haave very recently endeavored to show, in another work ('Asie
Centrale', t. i., p. 408). how the Scythian saga of the sacred gold, which
fell burning from heaven, and remained in the possession of the Golden Horde
of the Paralat¾ (Herod., iv., 5-7), probably originated in the vague
recollection of the fall of an aÂrolite. The ancients had also some
strange fictions (Dio Cassius, lxxv., 1259) or silver which had fallen from
heaven, and with which it had been attempted, under the Emperor Severus, to
cover bronze coins; metallic iron was however, known to exist in meteoric
stones. (Plin., ii., 56.) The frequently-recurring expression 'lapidibus
pluit' must not always be understood to refer to falls of aÂrolites. In
Liv., xxv., 7, it probably refers to pumice ('rapilli') ejected from the
volcano, Mount Albanus (Monte Cavo), which was not wholly extinguished at
the time. (See Heyne, 'Opuscula Acad.', t. iii., p. 261; and my 'Relation
Hist.', t. i., p. 394.) The contest of Hercules with the Ligyans, on the
road from the Caucasus to the Hesperides, belongs to a different sphere of
ideas, being an attempt to explain mythically the origin of the round quartz
blocks in the Ligyan field of stones at the mouth of the Rhone, which
Aristotle supposes to have been ejected from a fissure during an earthquake,
and Posidonius to have been caused by the force of the waves of an inland
piece of water. In the fragments that we still possess of the play of
®schylus, the 'Prometheus Delivered', every thing proceeds, however, in
part of the narration, as in a fall of aÂrolites, for Jupiter draws
together a cloud, and causes the "district around to be covered by a shower
of round stones". Posidonius even ventured to deride the geognostic myth of
the blocks and stones. The Lygian field of stones was, however, very
naturally and well described by the ancients. The district is now known as
'La Crau.' (See Guerin, 'Mesures BaromÂtriques dans les Alpes, et
MÂtÂorologie d'Avignon', 1829, chap. xii., p. 115.)
p 116
We can ascertain by measurement the enormous, wonderful, and wholly
planetary velocity of shooting stars, fire-valls and meteoric stones, and we
can gain a knowledge of what is the general and uniform character of the
phenomenon, but not of the genetically cosmical process and the results of
the metamorphoses. If meteoric stones while revolving in space are already
consolidated into dense masses,* less dense, however,
p 117
than the mean density of the earth, they must be very small nuclei, which
surrounded by inflammable vapor or gas, form the innermost part of
fire-balls, from the height and apparent diameter of which we may, in the
case of the largest, estimate that the actual diameter varies from 500 to
about 2800 feet.
[footnote] *The specific weight of aÂrolites varies from 1.9 (Alais) to 4.3
(Tabor). Their general density may be set down as 3, water being 1. As to
what has been said in the text of the actual diameters of fire-balls, we
must remark, that the numbers have been taken from the few measurements that
can be relied upon as correct. These give for the fire-ball of Weston,
Connecticut (14th December, 1807), only 500; for that observed by Le Roi
(10th July, 1771) about 1000 and for that estimated by Sir Charles Blagden
(18th January, 1783) 2600 feet in diameter. Brandes ('Unterhaltungen'
bd.i., s. 42) ascribes a diameter varying from 80 to 120 feet to shooting
stars, and a luminous train extending from 12 to 16 miles. There are,
however, ample optical causes for supposing that the apparent diameter of
fire-balls and shooting stars has been very much overrated. The volume of
the largest fire-ball yet observed can not be compared with that of Ceres,
estimating generally so exact and admirable treatise, 'On the Connection of
the Physical Sciences', 1835, p. 411.) With the view of elucidating what
has been stated in the text regarding the large zÂrolite that fell into the
bed of the River Narni, but has not again been found, I will give the
passage made known by Pertz, from the 'Chronicon Benedicti, Monachi Sancti
Andre¾ in Mont Soracte', a MS. belonging to the tenth century, and
preserved in the Chigi Library at Rome. The Barbarous Latin of that age has
been left unchanged. "Anno 921, temporibus domini Johannis Decimi pape, in
anno pontificatus illius 7 visa sunt signa. Nam juxta urben Romam lapides
plurimi de c¾lo cadere visi sunt. In civilate qu¾ vocatur Narnia tam diri
ac tetri, ut nihil aliud credatur, quam de infernalibus locis deducti
essent. Nam ita ex illis lapidibus unus omnium maximum est, ut decidens in
flumen Narnus, ad mensuram unius cubiti super aquas fluminus usque hodie
videretur. Nam et ignit¾ita ut pene terra contingeret. AliAnno 921,
temporibus domini Johannis Decimi pape, in anno pontificatus illius 7 visa
sunt signa. Nam juxta urben Romam lapides plurimi de c¾lo cadere visi
sunt. In civilate qu¾ vocatur Narnia tam diri ac tetri, ut nihil aliud
credatur, quam de infernalibus locis deducti essent. Nam ita ex illis
lapidibus unus omnium maximum est, ut decidens in flumen Narnus, ad mensuram
unius cubiti super aquas fluminus usque hodie videretur. Nam et ignit¾ ita
ut pene terra contingeret. Ali cadentes," etc. (Pertz, 'Monum. Germ. Hist.
Scriptores', t. iii., p. 715.) On the aÂrolites of gos Potamus, which
fell, according to the Parian Chroniccle, in the 78 1 Olympiad, see BÂckh,
'Corp. Inscr. Graec', t. ii., p. 302, 320, 340; also Aristot., 'Meteor.',
i., 7 (Ideler's 'Comm.', t. i., p. 404-407); Stob., 'Eel. Phys.', i., 25, p.
508 (Heeren); Plut., 'Lys.', c. 12; Diog. Laert., ii., 10; and see, also,
subsequent notes in this work. According to a Mongolisn tradition, a black
fragment of a rock, forty feet in height, fell from heaven on a plain near
the source of the Great Yellow River in Western China. (Abel RÂmusat, in
LamÂtherie, 'Jour. de Phys.', 1819, Mai p. 264.)
The largest meteoric masses as yet known are those of Otumpa, in Chaco, and
of Bahia, in Brazil, described by Rubi de Celis as being from 7 to 7 1/2
feet in length. The meteoric stone of gos Potamos, celebrated in antiquity,
and even mentioned in the Chronicle of the Parian Marbles, which fell about
the year in which Socrates was born, has been described as of the size of
two mill-stones, and equal in weight to a full wagon load. Notwithstanding
the failure that has attended the efforts of the African traveler, Brown, I
do not wholly relinquish the hope that, even after the lapse of 2312 years,
this Thracian meteoric mass, which it would be so difficult to destroy, may
be found, since the region in which it fell is now bcome so easy of access
to European travelers. The huge aÂrolite which in the beginning of the
tenth century fell into the river at Narni, projected between three and four
feet above the surface of the water, as we learn from a document lately
discovered by Pertz. It must be remarked that these meteoric bodies,
whether in ancient or modern times can only be regarded as the principal
fragments of masses that have been broken up by the explosion either of a
fire-ball of a dark cloud.
On considering the enormous velocity with which, as has been mathematically
proved, meteoric stones reach the earth from the extremest confines of the
atmosphere, and the lengthened course traversed by fire-balls through the
denser strata of the air, it seems more than improbable that these
metalliferous stony masses, containing perfectly-formed crystals of olivine,
labradorite, and pyroxene, should in so short a period of time has been
converted from a vaporous condition to a solid nucleus. Moreover, that
which falls from meteoric masses, even where the internal composition is
chemically different, exhibits almost always the peculiar character of a
fragment, being of a prismatic or truncated pyramidal form, with broad,
somewhat curved faces, and rounded angles. But whence comes this form,
which was first recognized by Schreiber as characteristic of the 'severed'
part of a rotating planetary body? Here, as in the sphere of organic life,
all that appertains to the history of development remains hidden in
obscurity. Meteoric masses become luminous and kindle at heights which
p 118
must be regarded as almost devoid of air, of occupied by an atmosphere that
does not even contain 1/100000th part of oxygen. The recent investigations
of Biot on the important phenomenon of twilight* have considerably lowered
the lines which had, perhaps with some degree of temerity, been usually
termed the boundaries of the atmosphere; but processes of light may be
evolved independently of the presence of oxygen, and Poisson conjectured
that aÂroliteswere ignited far beyond the range of our atmosphere.
Numerical calculation and geometrical measurement are the only means by
which as in the case of the larger bodies of our solar system, we are
enabled to impart a firm and safe basis to our investigations of meteoric
stones.
[footnote] *Biot, 'Trait d'Astronomie Physique' (3Âme Âd.), 1841, t.
i., p. 149, 177, 238, 312. My lamented friend Poisson endeavored, in a
singular manner, to solve the difficulty attending an assumption of the
spontaneous ignition of meteoric stones at an elevation where the density of
the atmosphere is almost null. These are his words: "It is difficult to
attribute, as is uaually done, the incandescence of aÂrolites to friction
against the molecules of the atmosphere at an elevation above the earth
where the density of the air is almost null. May we not suppose that the
electric fluid, in a neutral condition, forms a kind of atmosphere,
extending far beyond the mass of our atmosphere, yet subject to terrestrial
attraction, although physically imponderable, and consequently following our
globe in its motion? According to this hypothesis, the bodies of which we
have been speaking would, on entering this imponderable atmosphere,
decompose the neutral fluid by their unequal action on the two
electricities, and they would thus be heated, and in a state of
incandescence, by becoming electrified." (Poisson, 'Rech. sur la
Probabilit des Jugements', 1837, p. 6.)
Although Halley pronounced the great fire-ball of 1686, whose motion was
opposite to that of the earth in its orbit,* to be a cosmical body, Chadni,
in 1794, first recognized, with ready acuteness of mind, the connection
between fire-balls and the stones projected from the atmosphere, and the
motions of the former bodies in space.**
[footnote] *'Philos. Transact.', vol. xxix., p. 161-163.
[footnote] **The first edition of Chlandni's important treatise, 'Ueber den
Ursprung der von Pallas gefundenen und anderen Eisenmassen' (On the Origin
of the masses of Iron found by Pallas, and other similar masses), appeared
two months prior to the shower of stones at Siena, and two years before
Lichtenberg stated, in the 'GÂttingen Taschenbuch', that "stones reach our
atmosphere from the remoter regions of space.' Comp., also, Olbers's letter
to Benzenberg, 18th Nov., 1837, in Benzenberg's 'Treatise on Shooting
Stars', p. 186.
A brilliant confirmation of the cosmical origin of these phenomena has been
afforded by Denison Olmsted, at New Haven, Connecticut, who has shown on the
concurrent authority of all eye-witnesses, that during the celebrated fall
of shooting stars on the night between the 12th
p 119
and 13th of November, 1833, the fire-balls and shooting stars all emerged
from one and the same quarter of the heavens, namely, in the vicinity of the
star 'gamma' in the constellation Leo, and did not deviate from this point,
although the star changed its apparent height and azimuth during the time of
the observation. Such an independence of the Earth's rotation shows that
the luminous body must have reached our atmosphere from 'without.'
According to Encke's computation* of the whole
p 120
number of observations made in the United States of North America, between
the thirty-fifth and the forty-second degrees of latitude, it would appear
that all these meteors came from the same point of space in the direction in
which the Earth was moving at the time.
[footnote] *Encke, in Poggend., 'Annalen', bd. xxxiii. (1834), s. 213.
Arago, in the 'Annuaire' for 1836, p. 291. Two letters which I wrote to
Benzenberg, May 19 and October 22, 1837, on the conjectural precession of
the nodes in the orbit of periodical falls of shooting stars. (Benzenberg's
'Sternsch.', s. 207 and 209.) Olbers subsequently adopted this opinion of
the gradual retardation of the November phenomenon. ('Astron. Nachr.',
1838, No. 372, s. 180.) If I may venture to combine two of the falls of
shooting stars mentioned by the Arabian writers with the epochs found by
Boguslawski for the fourteenth century, I obtain the following more or less
accordant elements of the movements of the nodes:
In Oct., 902, on the night in which King Ibrahim ben Ahmed died, there
fell a heavy shower of shooting stars, "like a fiery rain;" and this year
was, therefore, called the year of stars. (Conde, 'Hist. de la Domin.' de
los Arabes', p. 346.)
On the 19th of Oct., 1202, the stars were in motion all night. "They
fell like locusts." ('Comptes Rendus', 1837, t. i., p. 294; and Fr¾hn, in
the 'Bull. de l'AcadÂmie de St. PÂtersbourg', t. iii., p. 308.)
On the 21st Oct., O.S., 1366, "'die sequente post festum XI. millia
Virginum ab hora matutina usque ad horam primam vis¾ sunt quasi stell¾ de
c¾lo cadere continuo, et in tanta multitudine, quod nemo narrare suf
ficit.'" This remarkable notice, of which we shall speak more fully in the
subsequent part of this work, was found by the younger Von Boguslawski, in
Benesse (de Horowic) de Weitmil or WeithmÂl, 'Chronicon Ecclesi¾
Pragensis', p. 389. This chronicle may also be found in the second part of
'Scriptores rerum Bohemicarum', by Pelzel and Dobrowsky, 1784. (Schum.,
'Astr. Nachr.', Dec., 1839.)
On the night between the 9th and 10th of November, 1787, many falling
stars were observed at Manheim, Southern Germany, by Hemmer (KÂmtz,
'Meteor.', th. iii., s. 237.)
After midnight, on the 12th of November, 1799, occurred the
extraordinary fall of stars at Cumana, which Bonpland and myself have
described, and which was observed over a great part of the earth. ('Relat.
Hist.', t. i., p. 519-527.)
Between the 12th and 13th of November, 1822, shooting stars,
intermingled with fire-balls, were seen in large numbers by Kloden, at
Potsdam. (Gilbert's 'Ann.', bd. lxxii., s. 291.)
On the 13th of November, 1831, at 4 o'clock in the morning, a great
shower of falling stars was seen by Captain BÂrard, on the Spanish coast,
near Carthagena del Levante. ('Annuaire', 1836, p. 297.)
In the night between the 12th and 13th of November, 1833, occurred the
phenomenon so admirably described by Professor Olmsted, in North America.
In the night of the 13-14th of November, 1834, a similar fall of
shooting stars was seen in North America, although the numbers were not
quite so considerable. (Poggend., 'Annalen', bd. xxxiv., s. 129.)
On the 13th of November, 1835, a barn was set on fire by the fall of a
sporadic fire-ball, at Belley, in the Department de l'Ain. ('Annuaire',
1836, p. 296.)
In the year 1838, the stream showed itself most decidedly on the night
of the 13-14th of November. ('Astron. Nachr.', 1838, No. 372.)
On the recurrence of falls of shooting stars in North America, in the month
of November of the years 1834 and 1837, and in the analogous falls observed
at Bremen in 1838, a like general parallelism of the orbits, and the same
direction of the meteors from the constellation Leo, were again noticed. It
has been supposed that a greater parallelism was observable in the direction
of periodic falls of shooting stars than in those of sporadic occurrence;
and it has further been remarked, that in the periodically-recurring falls
in the month of August, as, for instance, in the year 1839, the meteors came
principally from one point between Perseus and Taurus, toward the latter of
which constellations in the Earth was then moving. This peculiarity of the
phenomenon, manifested in the retrograde direction of the orbits in November
and August, should be thoroughly investigated by accurate observations, in
order that it may either be fully confirmed or refuted.
The heights of shooting stars, that is to say, the heights of the points at
which they begin and cease to be visible, vary exceedingly, fluctuating
between 16 and 140 miles. This important result, and the enormous velocity
of these problematical asteroids, were first ascertained by Benzenberg and
Brandes, by simultaneous observations and determinations of parallax at the
extremities of a base line of 49,020 feet in length.*
[footnote] *I am well aware that, among the 62 shooting stars
simultaneously observed in Silesia, in 1823, at the suggestion of Professor
Brandes some appeared to have an elevation of 183 to 240, or even 400 miles.
(Brandes, 'Unterhaltungen fÂr Freunde der Astronomie und Physik', heft i.,
s. 48. Instructive Narratives for the Lovers of Astronomy and Physics.)
But Olbers considered that all determinations for elevations beyond 120
miles must be doubtful, owing to the smallness of the parallax.
The relative velocity of motion is from 18 to 36 miles in a second, and
consequently equal to planetary velocity. This planetary velocity,* as well
as the direction of the orbits
p 121
of fire-balls and shooting stars, which has frequently been observed to be
opposite to that of the Earth, may be considered as conclusive arguments
against the hypothesis that aÂrolites derive their origin from the
so-called active 'lunar volcanoes.'
[footnote] *The planetary velocity of translation, the movement in the
orbit, is in Mercury 26.4, in Venus 19.2, and in the Earth 16.4 miles in a
second.
Numerical views regarding a greater or lesser volcanic force on a small
cosmical body, not surrounded by any atmosphere, must, from their nature, be
wholly arbitrary. We may imagine the reaction of the interior of a planet
on its crust ten or even a hundred times greater than that of our present
terrestrial volcanoes; the direction of masses projected from a satellite
revolving from west to east might appear retrogressive, owing to the Earth
in its orbit subsequently reaching that point of space at which these bodies
fall. If we examine the whole sphere of relations which I have touched upon
in this work, in order to escape the charge of having made unproved
assertions, we shall find that the hypothesis of the selenic origin of
meteoric stones* depends upon a number of conditions
p 122
whose accidental coincidence could alone convert a possible into an actual
fact.
[footnote] *Chladni states that an Italian physicist, Paolo Maria Terzago,
on the occasion of the fall of an aÂrolite at Milan in 1660, by which a
Franciscan monk was killed, was the first who surmised that aÂrolites were
of selenic origin. He says, in a memoir entitled 'Mus¾um Septalianum,
Manfredi Septal¾, Patricii Mediolanensis, industrioso labore constructum'
(Tortona, 1664, p. 44), "Labant philosophorum mentes sub horum lapidum
ponderibus; ni dicire velimus, lunan terram alteram, sine mundum esse, ex
cujus montibus divisa frustra in inferiorem nostrum hunc orben dela bantur."
Without any previous knowledge of this conjecture, Olbers was led, in the
year 1795 (after the celebrated fall at Siena on the 16th of June, 1794),
into an investigation of the amount of the initial tangential force that
would be requisite to bring to the Earth masses projected from the Moon.
This ballistic problem occupied, during ten or twelve years, the attention
of the geometricians Laplace, Biot, Brandes, and Poisson. The opinion which
was then so prevalent, but which has since been abandoned, of the existence
of active volcanoes in the Moon, where air and water are absent, led to a
confusion in the minds of the generality of persons between mathematical
possibilities and physical probabilities. Olbers, Brandes, and Chladni
thought "that the velocity of 16 to 32 miles, with which fire-balls and
shooting stars entered our atmosphere," furnished a refutation to the view
of their selenic origin. According to Olbers, it would require to reach the
Earth, setting aside the resistance of the air, an initial velocity of 8292
feet in the second; according to Laplace, 7862; to Biot, 8282; and to
Poisson, 7595. Laplace states that this velocity is only five or six times
as great as that of a cannon ball; but Olbers has shown "that, with such an
initial velocity as 7500 or 8000 feet in a second, meteoric stones would
arrive at the surface of our earth with a velocity of only 35,000 feet (or
1.53 German geographical mile). But the measured velocity of meteoric
stones averages five such miles, or upward of 114,000 feet to a second; and,
consequently, the original velocity of projection from the Moon must be
almost 110,000 feet, and therefore fourteen times greater than Laplace
asserted." (Olbers, in Schum, 'Jahrb.', 1837, p. 52-58; and in Gehler,
'Neues Physik.' 'WÂrterbuche', bd. vi., abth.3, s. 2199-2136.) If we
could assume volcanic forces to be still active on the Moon's surface, the
absence of atmospheric resistance would certainly give to their projectile
force an advantage over that of our terrestrial volcanoes; but even in
respect to the measure of the latter force (the projectile force of our own
volcanoes), we have no observations on which any reliance can be placed, and
it has probably been exceedingly overrated. Dr. Peters, who accurately
observed and measured the phenomena presented by ®tna, found that the
greatest velocity of any of the stones projected from the crater was only
1250 feet to a second. Observations on the Peak of Teneriffe, in 1798, gave
3000 feet. Although Laplace, at the end of his work ('Expos. du Syst. du
Monde', ed. de 1824, p. 399), cautiously observes, regarding aÂrolites,
"that in all probability they come from the depths of space," yet we see
from another passage (chap. vi., p. 233) 6that, being probably unacquainted
with the extraordinary planetary velocity of meteoric stones, he inclines to
the hypothesis of their lunar origin, always, however, assuming that the
stones projjected from the Moon "become satellites of our Earth, describing
around it more or less eccentric orbits, and thus not reaching its
atmosphere until several or even many revolutions have been accomplished."
As an Italian at Tortona had the fancy that aÂrolites came from the Moon,
so some of the Greek philosophers thought they came from the Sun. This was
the opinion of Diogenes Laertius (ii., 9) regarding the origin of the mass
that fell at "gos Potamos (see note, p. 116). Pliny, whose labors in
recording the opinions and statements of preceding writers are astonishing,
repeats the theory, and derides it the more freely, because he, with earlier
writers (Diog. Laert., 3 and 5, p. 99, HÂbner), accuses Anaxagoras of
having predicted the fall of aÂrolites from the
Sun: "Celebrant Gr¾ci Anaxagoram Clazomenium Olympiadis septuagesim¾
octav¾ secundo anno pr¾dixisse c¾lestium litterarum scientia quibus
diebus saxum casurum esse e sole, idque factum interdia in Thraci¾ parte ad
gos flumen. Quod si quis pr¾dictum credat, simul fateatur necesse est,
majoris miraculi divinitatem Anaxagor¾ fuisse, solvique rerum natur¾
intellectum, et confundi omnia, si aut ipse Sol lapis esse aut unquam
lapidem in eo fuisse credatur; decidere tamen crebro non erit dubium." The
fall of a moderate-sized stone, which is preserved in the Gymnasium at
Abydos, is also reported to have been foretold by Anaxagoras. The fall of
aÂrolites in bright sunshine, and when the Moon's disk was invisible,
probably led to the idea of sun-stones. Moreover, according to one of the
physical dogmas of Anaxagoras, which brought on him the persecution of the
theologians (even as they have attacked the geologists of our own times),
the Sun was regarded as "a molten fiery mass" ([Greed words]). In
accordance with these views of Anaxagoras, we find Euripides, in 'PhaÂton',
terming the Sun "a golden mass;" that is to say, a fire-colored,
brightly-shining matter, but not leading to the inference that aÂrolites
are golden sun-stones. (See note to page 115.) Compare Valckenaer,
'Diatribe in Eurip. perd. Dram. Reliquias', 1767, p. 30. Diog. Laert., ii.,
40. Hence, among the Greek philosophers, we find four hypotheses regarding
the origin of falling stars: a telluric origin from ascending exhalations;
masses of stone raised by hurricane (see Aristot., 'Meteor., lib. i., cap.
iv., 2-13, and cap. vii., 9); a solar origin; and, lastly, an origin in the
regions of space, as heavenly bodies which had long remained invisible.
Respecting this last opinion, which is that of Diogenes of Apollonia, and
entirely accords with that of the present day, see pages 124 and 125. It is
worthy of remark, that in Syria, as I have been assured by a learned
Orientalist, now resident at Smyrna, Andrea de Nericat, who instructed me in
Persian, there is a popular belief that aÂrolites chiefly fall on clear
moonlight nights. The ancients, on the contrary, especially looked for
their fall during lunar eclipses. (See Pliny, xxxvii., 10, p. 164.
Solinus, c. 37. Salm., 'Exere.', p. 531; and the passages collected by
Ukert, in his 'Geogr. der Griechen und RÂmer', th. ii., 1, s. 131, note
14.) On the improbability that meteoric masses are formed from
metal-dissolving gases, which, according to Fusinieri, may exist in the
highest strata of our atmosphere, and previously diffused through an almost
boundless space, may suddenly assume a solid condition, and on the
penetration and misceability of gases, see my '
Relat. Hist.', t. i., p. 525.
p 122
The view of the original existence of
p 123
small planetary masses in space is simpler, and at the same time, more
analogous with those entertained concerning the formation of other portions
of the solar system.
It is very probable that a large number of these cosmical bodies traverse
space undestroyed by the vicinity of our atmosphere, and revolve round the
Sun without experiencing any alteration but a slight increase in the
eccentricity of their orbits, occasioned by the attraction of the Earth's
mass. We may, consequently, suppose the possibility of these bodied
remaining invisible to us during many years and frequent revolutions. The
supposed phenomenon of ascending shooting stars and fire-balls, which
Chladni has unsuccessfully endeavored to explain on the hypothesis of the
'reflection' of strongly compressed air, appears at first sight as the
consequence of some unknown tngential force propelling bodies from the
earth; but Bessel has shown by theoretical deductions, confirmed by Feldt's
carefully-conducted calculations, that, owing to the absence of any proofs
of the simultaneous occurrence of the observed disappearances, the
assumptiopn of an ascent of shooting stars was rendered wholly improbable,
and inadmissible as a result of observation.*
[footnote] *Bessel, in Schum., 'Astr. Nachr.', 1839, No 389 und 381, s. 222
und 346. At the conclusion of the Memoir there is a comparison of the Sun's
longitudes with the epochs of the November phenomenon, from the period of
the first observations in Cumana in 1799,
The opinion advanced by Olbers that the explosion of shooting stars and
ignited fire-balls not moving in straight lines may impel meteors upward in
the manner of rockets, and influence the direction of their orbits, must be
made the subject of future researches.
Shooting stars fall either seprately and in inconsiderable numbers, that is,
sporadically, or in swarms of many thousands.
p 124
The latter, which are compared by Arabian authors to swarms of locusts, are
periodic in their occurrence, and move in streams, generally in a parallel
direction. Among periodic falls, the most celebrated are that known as the
November phenomenon, occurring from about the 12th to the 14th of November,
and that of the festival of St. Lawrence (the 10th of August), whose "fiery
tears" were noticed in former times in a church calendar of England, no less
than in old traditionary legends, as a meteorological event of constant
recurrence.*
[footnote] *Dr. Thomas Forster ('The Pocket Encyclopedia of Natural
Phenomena' 1827, p. 17) states that a manuscript is preserved in the library
of Christ's College, Cambridge,** written in the tenth century by a monk,
and entitled 'Ephemerides Rerum Naturalium', in which the natural phenomena
for each day of the year are inscribed as, for instance, the first flowering
of plants, the arrival of birds, etc.; the 10th of August is distinguished
by the word "meteorodes." It was this indication, and the tradition of the
fiery tears of St. Lawrence, that chiefly induced Dr. Forster to undertake
his extremely zealous investigation of the August phenomena. (Quetelet,
'Correspond. MathÂm.', SÂrie III., t. i., 1837, p. 433.)
[further footnote] **[No such manuscript is at present known to exist in
the library of that college. For this information I am indebted to the
inquiries of Mr. Cory, of Pembroke College, the learned editor of
'Hieroglyphics of Horapollo Nilous', Greek and English, 1840.] -- Tr.
Notwithstanding the great quantity of shooting stars and fire-balls of the
most various dimensions, which, according to KlÂden, were seen to fall at
Potsdam on the night between the 12th and 13th of November, 1822, and on the
same night of the year in 1832 throughout the whole of Europe, from
Portsmouth to Orenburg on the Ural River, and even in the southern
hemisphere, as in the Isle of France, no attention was directed to the
'periodicity' of the phenomenon, and no idea seems to have been entertained
of the connection existing between the fall of shooting stars and the
recurrence of certain days, until the prodigious swarm of shooting stars
which occurred in North America between the 12th and 13th of November, 1833,
and was observed by Olmsted and Palmer. The stars fell on this occasion,
like flakes of snow, and it was calculated that at least 240,000 had fallen
during a period of nine hours. Palmer, of New Haven, Connecticut, was led,
in consequence of this splendid phenomenon, to the recollection of the fall
of meteoric stones in 1799, first described by Ellicot and myself,* and
which, by
p 125
a comparison of the facts I had adduced, showed that the phenomenon had been
simultaneously seen in the New Continent, from the equator to New Herrnhut
in Greenland (65 degrees 14' north latitude), and between 46 degrees and 82
degrees longitude.
[footnote] *Humb., 'Rel. Hist.', t. i., p. 519-527. Ellicot in the
'Transactions of the American Society', 1804, vol. vi., . 29. Arago makes
the following observations in reference to the November phenomena: "We thus
become more and more confirmed in the belief that there exists a zone
composed of millions of small bodies, whose orbits cut the plane of the
ecliptic at about the point which out Earth annually occupies between the
11th and 13th of November. It is a new planetary world beginning to be
revealed to us." ('Annuaire', 1836, p. 296.)
The identity of the epochs was recognized with astonishment. The stream
which had been seen from Jamaica to Boston (40 degrees 21' north latitude)
to traverse the whole vault of heaven on the 12th and 13th of November,
1833, was again observed in the United States in 1834, on the night between
the 13th and 14th of November, although on this latter occasion it showed
itself with somewhat less intensity. In Europe the periodicity of the
phenomenon has since been manifested with great regularity.
Another and a like regularly recurring phenomenon is that noticed in the
month of August, the meteoric stream of St. Lawrence, appearing between the
9th and 14th of August. Muschenbrock,* as early as in the middle of the
last century, drew attention to the frequency of meteors in the month of
August' but their certain periodic return about the time of St. Lawrence's
day was first shown by Quetelet, Olbers, and Benzenberg.
[footnote] *Compare Muschenbroek, 'Introd. ad Phil. Nat.', 1762, t. ii., p.
1061; Howard, 'On the Climate of London', vol. ii., p. 23, observations of
the year 1806; seven years, therefore aftr the earliest observations of
Brandes (Benzenberg, 'Âber Sternschnuppen', s. 240-244); the August
observations of Thomas Forster, in Quetelet, op. cit., p. 438-453; those of
Adolph Erman, Boguslawski, and Kreil, in Schum., 'Jahrb.', 1838, s. 317-330.
Regarding the point of origin in Perseus, on the 10th of August, 1839, see
the accurate measurements of Bessel and Erman (Schum., 'Astr. Nachr.', No.
385 und 428); but on the 10th of August, 1837, the path does not apper to
have been retrograde; see Arago in 'Comptes Rendus', 1837, t. ii., p. 183.
We shall, no doubt, in time, discover other periodically appearing streams,*
probably about the 22d to the
p. 126
25th of April, between the 6th and 12th of December, and, to judge by the
number of true falls of aÂrolites enumerated by Capocci, also between the
27th and 29th of November, of about the 17th of July.
[footnote] *On the 25th of April, 1095, "innumerable eyes in France saw
stars falling from heaven as thickly as hail" ('ut grando, nisi lucerent,
pro densitate putaretur'; Baldr., p. 88), and this occurrence was regarded
by the Council of Clermont as indicative of the great movement in
Christendom. (Wilken, 'Gesch. der KreuzzÂge', bd. i., s. 75.) On the 25th
of April, 1800, a great fall of stars was observed in Virginia and
Massachusetts; it was "a fire of rockets that lasted two hours." Arago was
the first to call attention to the "trainÂe d'asteroÂdes," as a recurring
phenomenon. ('Annuaire', 1836, p. 297.) The falls of aÂrolites in the
beginning of the month of December are also deserving of notice. In
reference to their periodic recurrence as a meteoric stream, we may mention
the early observation of Brandes on the night of the 6th and 7th of
December, 1798 (when he counted 2000 falling stars), and very probably the
enormous fall of aÂrolites that occurred at the Rio Assu, near the village
of Macao, in the Brazils, on the 11th of December, 1836. (Brandes,
'Unterhalt. fÂr Freunde der Physik', 1825, heft i., s. 65, and 'Comptes
Rendus', t. v., p. 211.) Capocci, in the interval between 1809 and 1839, a
space of thirty years, has discovered twelve authenticated cases of
aÂrolites occurring between the 27th and 29th of November, besides others
on the 13th of November, the 10th of August, and the 17th of July.
('Comptes Rendus', t. xi., p. 357.) It is singular that in the portion of
the Earth's path corresponding with the months of January and February, and
probably also with March, no 'periodic' streams of falling stars of
aÂrolites have as yet been noticed; although when in the South Sea in the
year 1803, I observed on the 15th of March a remarkably large number of
falling stars, and they were seen to fall as in a swarm in the city of
Quito, shortly before the terrible earthquake of Riobamba on the 4th of
February, 1797. From the phenomena hitherto observed, the following epochs
seem especially worthy of remark:
22d to the 25th of April.
17th of July (17th to the 26th of July?). (Quet., 'Corr.', 1837, p. 435.)
10th of August.
12th to the 14th of November.
27th to the 29th of November.
6th to the 12th of December.
When we consider that the regions of space must be occupied by myriads of
comets, we are led by analogy, notwithstanding the differences existing
between isolated comets and rings filled with asteroids, to regard the
frequency of these meteoric streams with less astonishment than the first
consideration of the phenomenon would be likely to excite.
Although the phenomena hitherto observed appear to have been independent of
the distance from the pole, the temperature of the air, and other climatic
relations, there is, however, one perhaps accidentally coincident phenomenon
which must not be wholly disregarded. The Northern Light, the Aurora
Borealis, was unusually brilliant on the occurrence of the Borealis, was
unusually brilliant on the occurrence of the splendid fall of meteors of the
12th and 13th November, 1833, described by Olmsted. It was also observed at
Bremen in 1838, where the periodic meteoric fall was, however, less
remarkable than at Richmond, near London. I have mentioned in another work
the singular fact observed by Admiral Wrangel, and frequently confirmed to
me by himself,* that when he
p 127
was on the Siberian coast of the Polar Sea, he observed, during an Aurora
Borealis, certain portions of the vault of heaven which were not
illuminated, light up and continue luminous whenever a shooting star passed
over them.
[footnote] *Ferd. v. Wrangle, 'Reise lÂngs der NordkÂste von Sibirien in
den Jahren', 1820-1824, th. ii., s. 259. Regarding the recurrence of the
denser swarm of the November stream after an interval of thirty-three years,
see Olbers, in 'Jahrb.', 1837, s. 280. I was informed in Cumana that
shortly before the fearful earthquake of 1766, and consequently thirty-three
years (the same interval) before the great fall of stars on the 11th and
12th of November, 1799, a similar fiery manifestation had been observed in
the heavens. But it was on the 21st of October, 1766, and not in the
beginning of November, that the earthquake occurred. Possibly some traveler
in Quito may yet be able to ascertain the day on which the volcano of
Cayambe, which is situated there, was for the space of an hour enveloped in
falling stars, so that the inhabitants endeavored to appease heaven by
religious processions. ('Relat. Hist.', t. i., chap. iv., p 307; chap. x.,
p. 520 and 527.)
The different meteoric streams, each of which is composed of myriads of
small cosmical bodies, probably intersect our Earth's orbit in the same
manner as Biela's comet. According to this hypothesis, we may represent to
ourselves these asteroid-meteors as composing a closed ring or zone, within
which they all pursue one common orbit. The s aller planets between Mars
and Jupiter present us if we except Pallas with an analogous relation in
their constantly intersecting orbits. As yet, however, we have no certain
knowledge as to whether changes in the periods at which the stream becomes
visible, or the 'retardations' of the phenomena of which I have already
spoken, indicate a regular precession of oscillation of the nodes -- that is
to say, of the points of intersection of the Earth's orbit and of that of
the ring; or whether this ring or zone attains so considerable a degree of
breadth from the irregular grouping and distances apart of the small bodies,
that it requires several days for the Earth to traverse it. The system of
Saturn's satellites shows us likewise a group of immense width, composed of
most intimately-connected cosmical bodies. In this system, the orbit of the
outermost (the seventh) satellite has such a vast diameter, that the Earth,
in her revolution round the Sun, requires three days to traverse an extent
of space equal to this diameter. If, therefore, in one of these rings,
which we regard as the orbit of a periodical stream, the asteroids should be
so irregularly distributed as to consist of but few groups sufficiently
dense to give rise to these phenomena, we may easily understand why we so
seldom witness such glorious spectacles as those exhibited in the November
months of 1799 and 1833. The acute mind of Olbers led him almost to predict
that the next appearance of the phenomenon of shooting stars and fire-balls
intermixed, falling like flakes of snow, would not recur until between the
12th and 14th of November, 1867.
p 128
The stream of the November asteroids has occasionally only been visible in a
small section of the Earth. Thus, for instance, a very splendid 'meteoric
shower' was seen in England in the year 1837, while a most attentive and
skillful observer at Braunsberg, in Prussia only saw on the same night,
which was there uninterruptedly clear, a few sporadic shooting stars fall
between seven o'clock in the evening and sunrise the next morning. Bessel*
concluded from this "that a dense group of the bodies composing the great
ring may have reached that part of the Earth in which England is situated,
while the more eastern districts of the Earth might be passing at the time
through a part of the meteoric ring proportionally less densely studded with
bodies."
[footnote] *From a letter to myself, dated Jan. 24th, 1838. The enormous
swarm of falling stars in November, 1799, was almost exclusively seen in
America, where it was witnessed from New Herrnhut in Greenland to the
equator. The swarms of 1831 and 1832 were visible only in Europe, and those
of 1833 and 1834 only in the United States of North America.
If the hypothesis of a regular progression or oscillation of the nodes
should acquire greater weight, special interest will be attached to the
investigation of older observations. The Chinese annals, in which great
falls of shooting stars, as well as the phenomena of comets, are recorded,
go back beyond the age of Tyrt¾s, or the second Messenian war. They give a
description of two streams in the month of March, one of which is 687 years
anterior to the Christian era. Edward Biot has observed that among the
fifty-two phenomena which he has collected from the Chinese annals, those
that were of most frequent recurrence are recorded at periods nearly
corresponding with the 20th and 22d of July, O.S., and might consequently be
identical with the stream of St. Lawrence's day, taking into account that it
has advanced since the epochs* indicated.
[footnote] *Lettre de M. Edouard Biot  M. Quetelet, sur les anciennes
apparitions d'Etoiles Filantes en Chine, in the 'Bull. de l'AcadÂmie de
Bruxelles', 1843, t. x., No. 7, p. 8. On the notice from the 'Chronicon
Ecclesi¾ Pragensis', see the younger Boguslawski, in Poggend., 'Annalen',
bd. xlviii., s. 612.
If the fall of shooting stars of the 21st of October, 1366, O.S. (a notice
of which was found by the younger Von Boguslawski, in Benessius de Horowic's
'Chronicon Ecclesi¾ Pragensis'), be identical with our November phenomenon,
although the occurrence in the fourteenth century was seen in broad
daylight, we find by the precession in 477 years that this system of
meteors, or, rather, its common center of gravity, must describe
p 129
a retrograde orbit round the Sun. It also follows, from the views thus
developed, that the non-appearance, during certain years, in any portion of
the Earth, of the two streams hitherto observed in November and about the
time of St. Lawrence's day, must be ascribed either to an interruption in
the meteoric ring, that is to say, to intervals occurring between the
asteroid groups, or, according to Poisson to the action of the larger
planets* on the form and position of this annulus.
[footnote] *"It appears that an apparently inexhaustible number of bodies,
too small to be observed, are moving in the regions of space, either around
the Sun or the planets, or perhaps even around their satellites. It is
supposed that when these bodies come in contact with our atmosphere, the
difference between their velocity and that of our planet is so great, that
the friction which they experience from their contact with the air heats
them to incandescence, and sometimes causes their explosion. If the group
of falling stars form an annulus around the Sun, its velocity of circulation
may be very different from that of our Earth; and the displacements it may
experience in space, in consequence of the actions of the various planets,
may render the phenomenon of its intersecting the planes of the ecliptic
possible at some epochs, and altogether impossible at others." -- Poisson,
'Recherches sur la Probabilit des Jugements', p. 306, 307.
The solid masses which are observed by night to fall to the earth from
fire-balls, and by day generally when the sky is clear, from a cark small
cloud, are accompanied by much candescence. They undeniably exhibit a great
degree of general identity with respect to their external form, the
character of their crust, and the chemical composition of their principal
constituents. These characteristics of identity have been observed at all
the different epochs and in the most various parts of the earth in which
these meteoric stones have been found. This striking and early-observed
analogy of physiognomy in the denser meteoric masses is, however, met by
many exceptions regarding individual points. What differences, for
instance, do we not find between the malleable masses of for instance, do we
not find between the malleable masses of iron of Hradeschina in the district
of Agram, those from the shores of the Sisim in the government of Jeniseisk,
rendered so celebrated by Pallas, or those which I brought from Mexico,* all
of which contain 96 per cent. of iron, from the aÂrolites of Siena, in
which the iron scarcely amounts to 2 per cent., or the earthy aÂrolite of
Alais (in the Department du Gard), which broke up in water, or, lastly, from
those of Jonzac and Javenas, which contained no metallic iron, but presented
a
p 130
mixture of oryctognostically distinct crystalline compoonents!
[footnote] *Humboldt, 'Essai Politique sur la Nouv. Espagne' (2de Âdit.),
t. iii. p. 310.
These differences have led mineralogists to separate these cosmical masses
into two classes, namely, those containing nickelliferous meteoric iron, and
those consisting of fine or coarsely-granular meteoric dust. The crust or
rind of aÂrolites is peculiarly characteristic of these bodies, being only
a few tenths of a line in thickness, often glossy and pitch-like, and
occasionally veined.*
[footnote] *The peculiar color of their crust was observed even as early as
in the time of Pliny (ii., 56 and 58): "colore adusto." The phrase
"lateribus pluisse" seems also to refer to the burned outer surface of
aÂrolites.
There is only one instance on record, as far as I am aware (the aÂrolite of
Chantonnay, in La VendÂe), in which the rind was absent, and this meteor,
like that of Juvenas, presented likewise the peculiarity of having pores and
vesicular cavities. In all other cases the black crust is divided from the
inner light-gray mass by as sharply-defined a line of separation as is the
black leaden-colored investment of the white granit blocks* which I brought
from the cataracts of the Orinoco, and which are also associated with many
other cataracts, as, for instance, those of the Nile and of the Congo River.
[footnote] * Humb., 'Rel. Hist.', t. ii., chap xx., p. 299-302.
The greatest heat employed in our porcelain ovens would be insufficient to
produce any thing similar to the crust of meteoric stones, whose interior
remains wholly unchanged. Here and there, facts have been observed which
would seem to indicate a fusion together of the meteoric fragments; but, in
general, the character of the aggregate mass, the absence of compression by
the fall, and the inconsiderable degree of heat possessed by these bodies
when they reach the earth, are all opposed to the hypothesis of the interior
being in a state of fusion during their short passage from the boundary of
the atmosphere to our Earth.
The chemical elements of which these meteoric masses consist, and on which
Berzelius has thrown so much light, are the same as those distributed
throughout the earth's crust, and are fifteen in number, namely, iron,
nickel, cobalt, manganese, chromium, copper, arsenic, zinc, potash, soda,
sulphur, phosphorus, and carbon, constituting altogether nearly one third of
all the known simple bodies. Notwithstanding this similarity with the
primary elements into which inorganic bodies are chemically reducible, the
aspect of aÂrolites, owing to the mode in which their constituent parts are
compounded, presents, generally, some features foreign to our telluric rocks
and minerals. The pure native iron, which is almost always
p 131
found incorporated with aÂrolites, imparts to them a peculiar, but not
consequently, a 'selenic' character; for in other regions of space, and in
other cosmical bodies besides our Moon, water may be wholly absent, and
processes of oxydation of rare occurence.
Cosmical gelatinous vesicles, similar to the organic 'nostoc' (masses which
have been supposed since the Middle Ages to be connected with shooting
stars), and those pyrites of Sterlitamak, west of the Uralian Mountains,
which are said to have constituted the interior of hailstones,* must both be
classed among the mythical fables of meteorology.
[footnote] *Gustav Rose, 'Reise nach dem Ural', bd. II., s. 202.
Some few aÂrolites, as those composed of a finely granular tissue of
olivine, augite, and labradorite blended together* (as the meteoric stone
found at Juvenas, in the Department de l'ArdÂche, which resembled
dolorite), are the only ones, as Gustav Rose has remarked, which have a more
familiar aspect.
[footnote] *Gustav Rose, in Poggend., 'Ann.', 1825, bd. iv., x. 173-192.
Rammelsberg, 'Erstes Suppl. zum chem. HandwÂrterbuche der Mineralogie',
1843, s. 102. "It is," says the clear-minded observer Olbers, "a remarkable
but hitherto unregarded fact, that while shells are found in secondary and
tertiary formations, no 'fossil meteoric stones' have as yet been
discovered. May we conclude from this circumstance that previous to the
present and last modification of the earth's surface no meteoric stones fell
on it, although at the present time it appears probable, from the researches
of Schreibers, that 700 fall annually?" (Olbers, in Schum., 'Jahrb.', 1838,
s. 329.) Problematical nickelliferous masses of native iron have been found
in Northern Asia (at the gold-washing establishment at Petropawlowsk, eighty
miles southeast of Kusnezk), imbedded thirty-one feet in the ground, and
more recently in the Western Carpathians (the mountain chain of Magura, at
Szlanicz), both of which are remarkably like meteoric stones. Compart
Erman, 'Archiv fÂr wissenschaftliche Kunde von Russland', bd. i., s. 315,
and Haidinger, 'Bericht Âber Szlaniczer SchÂrfe in Ungarn.'
These bodiescontain, for instance, crystalline substances, perfectly similar
to those of our earth's crust; and in the Siberian mass of meteoric iron
investigated by Pallas, the olivine only differs from common olivine by the
absence of nickel, which is replaced by the oxyd of tin.*
[footnote] *Berzelius, 'Jahresber.', bd. xv., s. 217 und 231. Rammelsberg,
'HandwÂrterb., abth. ii., s. 25-28.
As meteoric olivine, like our basalt, contains from 47 to 49 per cent. of
magnesia, constituting, according to Berzelius, almost the half of the
earthy components of meteoric stones, we can not be surprised at the great
quantity of silicate of magnesia found in these cosmical bodies. If the
zÂrolite of Juvenas contain separable crystals of augite and labradorite,
the numerical relation of the constituents
p 132
render it at least probable that the meteoric masses of Chateau-Renard may
be a compound of diorite, consisting of hornblende and albite, and those of
Blansko and Chantonnay compounds of hornblende and labradorite. The proofs
of the telluric and atmospheric origin of aUerolites, which it is attempted
to base upon the oryctognostic analogies presented by these bodies, do not
appear to me to possess any great weight.
Recalling to mind the remarkable interview between Newton and Conduit at
Kensington,* I would ask why the elementary substances that compose one
group of cosmical bodies, or one planetary system, may not, in a great
measure, be identical?
[footnote] * "Sir Isaac Newton said he took all the planets to be composed
of the same matter with the Earth, viz., earth, water, and stone, but
variously connected." -- Turner, 'Collections for the History of Grantham,
containing authentic Memoirs of Sir Isaac Newton', p. 172.
Why should we not adopt this view, since we may conjecture that these
planetary bodies, like all the larger or smaller agglomerated masses
revolving round the sun, have been thrown off from the once far more
expanded solar atmosphere, and been formed from vaporous rintgs describing
their orbits round the central body? We are not, it appears to me, more
justified in applying the term telluric to the nickel and iron, the olivine
and pyroxene (augite), found in meteoric stones, than in indicating the
German plants which I found beyond the Obi as European species of the flora
of Northern Asia. If the elementary substances composing a group of
cosmical bodies of different magnitudes be identical, why should they not
likewise, in obeying the laws of mutual attraction, blend together under
definite relations of mixture, composing the white glittring snow and ice in
the polar zones of the planet Mars, or constituting in the smaller cosmical
masses mineral bodies inclosing crystals of olivine, augite, and
labradorite? Even in the domain of pure conjecture we should not suffer
ourselves to be led away by unphilosophical and arbitrary views devoid of
the support of inductive reasoning.
Remarkable obscurations of the sun's disk, during which the stars have been
seen at mid-day (as, for instance, in the obscuration of 1547, which
continued for three days, and occurred about the time of the eventful battle
of MÂhlberg), can not be explained as arising from volcanic ashes or mists,
and were regarded by Kepler as owing either to a 'materia cometica', or to a
black cloud formed by the sooty exhalations of the solar body. The shorter
obscurations of 1090 and 1203, which continued, the one only three, and the
other six
p 133
hours, were supposed by Chladni and Schnurrer to be occasioned by the
passage of meteoric masses before the sun's disk. Since the period that
streams of meteoric shooting stars were first considered with reference to
the direction of their orbit as a closed ring, the epochs of these
mysterious celestial phenomena have been observed to present a remarkable
connection with the regular recurrence of swarms of shooting stars Adolph
Erman has evinced great acuteness of mind in his accurate investigation of
the facts hitherto observed on this subject, and his researches have enabled
him to discover the connection of the sun's conjunction with the August
asteroids on the 7th of February, and with the November asteroids on the
12th of May, the latter period corresponding with the days of
St. Mamert (May 11th), St. Pancras (May 12th), and St. Servatius (May 13th),
which according to popular belief, were accounted "cold days."*
[footnote] Adolph Erman, in Poggend., 'Annalen', 1839, bd. xlviii., s.
582-601. Biot had previously thrown doubt regarding the probability of the
November stream reappearing in the beginning of May ('Comptes Rendus', 1836,
t. ii., p. 670). MÂdler has examined the mean depression of temperature on
the three ill-named days of May by Berlin observations for eighty-six years
('Verhandl. des Vereins zur BedfÂrd, des Gartenbaues', 1834, s. 377), and
found a retrogression of temperature amounting to 2.2 degrees Fahr. from the
11th to the 13th of May, a period at which nearly the most rapid advance of
heat takes place. It is much to be desired that this phenomenon of
depressed temperature, which some have felt inclined to attribute to the
melting of the ice in the northeast of Europe, should be also investigated
in very remote spots, as in America, or in the southern hemisphere. (Comp.
'Bull. de l'Acad. Imp. de St. PÂtersbourg', 1843, t. i., No. 4.)
The Greek natural philosophers, who were but little disposed to pursue
observations, but evinced inexhaustible fergility of imagination in giving
the most various interpretation of half-perceived facts, have, however, left
some hypotheses regarding shooting stars and meteoric stones which
strikingly accord with the views now almost universally admitted of the
cosmical process of these phenomena. "Falling stars," says Plutarch, in his
life of Lysander,* are, according to the opinion of some physicists, not
eruptions of the ethereal fire extinguished in the air immediately after its
ignition, nor yet an inflammatory combustion of the air, which is dissolved
in large quantities in the upper regions of space, but these meteors are
rather a fall of celestial bodies, which, in consequence of a certain
intermission in the rotatory force, and by the impulse of some irregular
movements, have been hurled down not only to the inhabited portions of the
Earth, but also beyond it into the great ocean, where we can not find them."
[footnote] *Plut., 'Vit¾ par, in Lysandro', cap. 22. The statement of
Damachos (DaÂmachos), that for seventy days continuously there was a fiery
cloud seen in the sky, emitting sparks like falling stars, and which then,
sinking nearer to the earth, let fall the stone of ®gos Potamos, "which,
however, was only a small part of it," is extremely improbable, since the
direction and velocity of the fire-cloud would in that case of necessity
have to remain for so many days the same as those of the earth; and this, in
the fire-ball of the 19th of July, 1686, described by Halley ('Trans.', vol.
xxix., p. 163), lasted only a few minutes. It is not altogether certain
whether DaÂmachos, the writer, [Greek words], was the same person as
DaÂmachos of Plat¾a, who was sent by Selencus to India to the son of
Androcottos, and who ws charged by Strabo with being "a speaker of lies" (p.
70, Casaub.). From another passage of Plutarch ('Compar. Solonis c. Cop.',
cap. 5) we should almost believe that he was. At all events, we have here
only the evidence of a very late author, who wrote a century and a half
after the fall of aÂrolites occurred in Thrace, and whose authenticity is
also doubted by Plutarch.
Diogenes of Apollonia* expresses himself still more explicitly.
[footnote] *Stob., ed. Heeren, i., 25, p. 508; Plut., 'de plac. Philos.',
ii., 13.
According to his views, "Stars that are 'invisible', and, consequently, have
no name, move in space together with those that are visible. These
invisible stars frequently fall burning at ®gos Potamos." The Apollonian,
who held all other stellar bodies, when luminous, to be of a pumice-like
nature, probably grounded his opinions regarding shooting stars and meteoric
masses on the doctrine of Anaxagoras the Clazomenian, who regarded all the
bodies in the universe "as fragments of rocks, which the fiery ether, in the
force of its gyratory motion, had torn from the Earth and converted into
stars." In the Ionian school, therefore, according to the testimony
transmitted to us in the views of Diogenes of Apollonia, aÂrolites and
stars were ranged in one and the same class; both, when considered with
reference to their primary origin, being equally telluric, this being
understood only so far as the Earth was then regarded as a central body,*
p 135
forming all things around it in the same manner was we, according to our
present views, suppose the planets of our system to have originated in the
expanded atmosphere of another central body, the Sun.
[footnote] *The remarkable passage in Plut., 'de plac. Philos.', ii., 13,
runs thus: "Anaxagoras teaches that the surrounding ether is a fiety
substance, which, by the power of its rotation, tears rocks from the earth,
inflames them, and converts them into stars." Applying an ancient fable to
illustrate a physical dogma, the Clazomenian appears to have ascribed the
fall of the Nem¾an Lion to the Peloponnesus from the Moon to such a
rotatory or centrifugal force. (®lian., xii., 7; Plut., 'de Facie in Orge
Lun¾' c. 24; Schol. ex Cod. Paris., in 'Apoll. Argon.', lib. i., p. 498,
ed. Schaef., t. ii., p. 40; Meineke, 'Annal. Alex.', 1843, p. 85.) Here,
instead of stones from the Moon, we have an animal from the Moon! According
to an acute remark of BÂckh, the ancient mythology of the Nem¾an lunar
lion has an astronomical origin, and is symbolically connected in chronology
with the cycle of intercalation of the lunar year, with the moon-worship at
Nem¾a, and the games by which it was accompanied.
These views must not, therefore, be confounded with what is commonly termed
the telluric or atmospheric origin of meteoric stones, nor yet with the
singular opinion of Aristotle, which supposed the enormous mass of ®gos
Potamos to have been raised by a hurricane. That rrogant spirit of
incredulity, which rejects facts without attempting to investigate them, is
in some cases almost more injurious than an unquestioning credulity. Both
are alike detrimental to the force of investigation. Notwithstanding that
for more than two thousand years the annals of different nations had
recorded falls of meteoric stones, many of which had been attested beyond
all doubt by the evidence of irreproachable eye-witnesses -- notwithstanding
the important part enacted by the B¾tylia in the meteor-worship of the
ancients -- notwithstanding the fact of the companions of Cortez having see
an aÂrolite at Cholula which had fallen on the neighboring pyramid --
notwithstanding that califs and Mongolian chiefs had caused swords to be
forged from recently-fallen meteoric stones -- nay, notwithstanding that
several persons had been struck dead by stones falling from heaven, as for
instance, a monk at Crema on the 4th of September, 1511, another monk at
Milan in 1650, and two Swedish sailors on board ship in 1674, yet this great
cosmical phenomenon remained almost wholly unheeded, and its intimate
connection drawn to the subject by Chladni, who had already gained immortal
renown by his discovery of the sound-figures. He who is penetrated with a
sense of this mysterious connection, and whose mind is open to deep
impressions of nature, will feel himself moved by the deepest and most
solemn emotion at the sight of every star that shoots across the vault of
heaven, no less than at the glorious spectacle of meteoric swarms in the
November phenomenon or on St. Lawrence's day. Here motion is suddenly
revealed in the midst of nocturnal rest. The still radiance of the vault of
heaven is for a moment animated with life and movement. In the mild
radiance left on the track of the shooting star, imagination pictures the
lengthened path of the meteor through the vault of heaven,
p 136
while, every where around, the luminous asteroids proclaim the existence of
one common material universe.
If we compare the volume of the innermost of Saturn's satellites, or that of
Ceres, with the immense volume of the Sun, all relations of magnitude vanish
from our minds. The extinction of suddenly resplendent stars in Cassiopeia,
Cygnus, and Serpentarius have already led to the assumption of other and
non-luminous cosmical bodies. We now know that the meteoric asteroids,
spherically agglomerated into small masses, revolve round the Sun,
intersect, like comets, the orbits of the luminous larger planets, and
become ignited either in the vicinity of our atmosphere or in its upper
strata.
The only media by which we are brought in connection with other planetary
bodies, and with all portions of the universe beyond our atmosphere, are
light and heat (the latter of which can scarcely be separated from the
former),* and those mysterious powers of attraction exercised by remote
masses, according to the quantity of their constituents, upon our globe, the
ocean, and the strata of our atmosphere.
[footnote' *The following remarkable passage on the radiation of heat from
the fixed stars, and on their low combustion and vitality -- one of Kepler's
many aspirations -- occurs in the 'Paralipom. in Vitell. Astron.
parsOpticqa', 1604, Propos. xxxii., p. 25: "Luciis proprium est calor,
sydera omnia calefaciunt. De syderum luce claritatis ratio testatur,
calorem universorum in minori esse proportione ad calorem unius solis, quam
ut ab homine, cujus est certa caloris mensura, utrque simul percipi et
judicari possit. De cincindularum lucula tenuissima negare non potes, quin
cum calore sit. Vivunt enim et moventur, hoc auten non sine calefactione
perficitur. Sic neque putrescentium lignorum lux sui calore destituitur;
nam ipsa puetredo quidam lentus ignis est. Inest et stirpibus suus calor."
(Compare Kepler, 'Epit. Astron. Copernican¾', 1618, t. i., lib. i., p. 35.)
Another and different kind of cosmical, or, rather, material mode of contact
is, however, opened to us, if we admit falling stars and meteoric stones to
be planetary asteroids. They not only act upon us merely from a distance by
the excitement of luminous or calorific vibrations, or in obedience to the
laws of mutual attraction, but they acquire an actual material existence for
us, reaching our atmosphere from the remoter regions of universal space, and
remaining on the earth itself. Meteoric stones are the only means by which
we can be brought in possible contact with that which is foreign to our own
planet. Accustomed to gain our knowledge of what is not telluric solely
through measurement, calculations, and the deductions of reason, we
experience a sentiment of astonishment at finding that we may examine,
weigh, and analyze bodies that appertain
p 137
to the outer world. This awakens, by the power of the imagination, a
meditative, spiritual train of thought, where the untutored mind perceives
only scintillations of light in the firmament, and sees in the blackened
stone that falls from the exploded cloud nothing beyond the rough product of
a powerful natural force.
Although the asteroid-swarms, on which we have been led, from special
predilection, to dwell somewhat at length, approximate to a certain degree,
in their inconsiderable mass and the diversity of their orbits, to comets,
they present this essential difference from the latter bodies, that our
knowledge of their existence is almost entirely limited to the moment of
their destruction, that is, to the period when, drawn within the sphere of
the Earth's attraction they become luminous and ignite.
In order to complete our view of all that we have learned to consider as
appertaining to our solar system, which now, since the discovery of the
small planets, of the interior comets of short revolutions, and of the
meteoric asteroids, is so rich and complicated in its form, it remains for
us to speak of the ring of Zodiacal light, to which we have already alluded.
Those who have lived for many years in the zone of palms must retain a
pleasing impression of the mild radiance with which the zodiacal light,
shooting pyramidally upward, illumines a part of the uniform length of
tropical nights. I have seen it shine with an intensity of light equal to
the milky way in Sagittarius, and that not only in the rare and dry
atmosphere of the summits of the Andes, at an elevation of from thirteen to
fifteen thousand feet, but even on the boundless grassy plains, the Illanos
of Venezuela, and on the sea-shore, beneath the ever-clear sky of Cumana.
This phenomenon was often rendered especially beautiful by the passage of
light, fleecy clouds, which stood out in picturesque and bold relief from
the luminous back-ground. A notice of this aÂrial spectacle is contained
in a passage in my journal, while I was on the voyage from Lima to the
western coasts of Mexico: "For three or four nights (between 10¼degrees
and 14¼degrees north latitude) the zodiacal light has appeared in greater
splendor than I have ever observed it. The transparency of the atmosphere
must be remarkably great in this part of the Southern Ocean, to judge by the
radiance of the stars and nebulous spots. From the 14th to the 19th of
March a regular interval of three quarters of an hour occurred between the
disappearance of the sun's disk in the ocean and the first manifestation of
the zodiacal
p 138
light, although the night was already perfectly dark. an hour after sunset
it was seen in great briliancy between Aldebaran and the Pleiades; and on
the 18th of March it attained an altitude of 39¼degrees5'minutes. Narrow
elongated clouds are scattered over the beautiful deep azure of the distant
horizon, flitting past the zodiacal light as before a golden curtain. Above
these, other clouds are from time to time reflecting the most brightly
variegated colors. It seems a second sunset. On this side of the vault of
heaven the lightness of the night appears to increase almost as much as at
the first quarter of the moon. Toward 10 o'clock the zodiacal light
generally becomes very faint in this part of the Southern Ocean, and at
midnight I have scarcely been able to trace a vestige of it. On the 16th of
March, when most strongly luminous a faint reflection was visible in the
east." In our gloomy so-called "temperate" northern zone, the zodiacal
light is only distinctly visible in the beginning of Spring, after the
evening twilight, in the western part of the sky, and at the close of
Autumn, before the dawn of day, above the eastern horizon.
It is difficult to understand how so striking a natural phenomenon should
have failed to attract the attention of physicists and astronomers until the
middle of the seventeenth century, or how it could have escaped the
observation of the Atabian natural philosophers in ancient Bactria, on the
euphrates, and in the south of Spain. Almost equal surprise is excited by
the tardiness of observation of the nebulous spots in Andromeda and Orion,
first described by Simon Marius and Huygens. The earliest explicit
descriptions of the zodiacal light occurs in Childrey's 'Britannia
Baconica',* in the year 1661.
p 139
[footnote] *"There is another thing which I recommend to the observation of
mathematical men, which is that in February, and for a little before and a
little after that month (as I have observed several years together), about
six in the evening, when the twilight hath almost deserted the horizon, you
shall see a plainly discernible way of the twilight striking up toward the
Pleiades, and seeming almost to touch them. It is so observed any clear
night, but it is best illac nocte. There is no such way to be observed at
any other time of the year (that I can perceive), nor any other way at that
time to be perceived darting up elsewhere; and I believe it hath been, and
will be constantly visible at that time of the year; but what the cause of
it in nature should be, I can not yet imagine, but leave it to future
inquiry." (Childrey, 'Britannia Baconica', 1661, p. 183.) This is the
first view and a simple description of the phenomenon. (Cassini,
'DÂcouverte de la Lumi dfd Âleste qui paroÂt dans le Zodiaque', in the
'MÂm. de l'Acad.', t. viii., 1730, p 276. Mairan, 'TraitÂPhys de l'Aurore
BorÂale', 1754, 0. 16.) In this remarkable work by Childrey there are to
be found (p. 91) very clear accounts of the epochs of maxima and minima
diurnal and annual temperatures, and of the retardation of the extremes of
the effects in meteorological processes. It is, however, to be regretted
that our Baconian-philosophy-loving author, who was Lord Henry Somerset's
chaplain, fell into the same error as Bernardin de St. Pierre, and regarded
the Earth as elongated at the poles (see p. 148). At the first he believes
that the Earth was spherical, but supposes that the uninterrupted and
increasing addition of layers of ice at both poles has changed its figure;
and that as the ice is formed from water, the quantity of that liquid is
every where diminishing.
The first observation of the phenomenon may have been made two or three
years prior to this period; but, notwithstanding, the merit of having (in
the spring of 1683) been the first to investigate the phenomenon in all its
relations in space is incontestably due to Dominicus Cassini. The light
which he saw at Bologna in 1668, and which was observed at the same time in
Persia by the celebrated traveler Chardin (the court astrologers of Ispahan
called this light, which had never before been observed, 'nyzek', a small
lance), was not the zodiacal light, as has often been asserted,* but the
p 140
enormous tail of a comet, whose head was concealed in the vapory mist of the
horizon, and which, from its length and appearance, presented much
similarity to the great comet of 1843.
[footnote] *Dominicus Cassini ('MÂm. de l'Acad.', t. viii., 1730, p. 188),
and Mairan ('Aurore Bor.', p. 16), have even maintained that the phenomenon
observed in Persia in 1668 was the zodiacal light. Delambre ('Hist. de
l'Astron. Moderne', t. ii., p. 742), in very decided trms ascribes the
discovery of this light to the celebrated traveler Chardin; but in the
'Couronnement de Soliman', and in several passages of the narrative of his
travels (Âd. de LanglÂs. t. iv., p. 326; t. x., p. 97), he only applies
the term niazouk (nyzek), or "petite lance," to "the great and famous comet
which appeared over nearly the whole world in 1668, and whose head was so
hidden in the wewst that it could not be perceived in the horizon of
Ispahan" ('Atlas du Voyage de Chardin', Tab. iv.; from the observations at
Schiraz). The head or nucleus of the comet was, however, visible in the
Brazils and in India (PingrÂ, 'ComÂtogr.', t. ii., p. 22). Regarding the
conjectured identity of the last great comet of March, 1843, with this,
which Cassini mistook for the zodiacal light, see Schum., 'Astr. Nachr.',
1843, No. 476 and 480. In Persian, the term "nizehi ÂteschÂn"(fiery
spears or lances) is also applied to the rays of the rising or setting sun,
in the same way as "nayÂzik," according to Freytag's Arabic Lexicon,
signifies "stell¾ cadentes." The comparison of comets to lances and swords
was, however, in the Middle Ages, very common in all languages. The great
comet of 1500, which was visible from April to June, was always termed by
the Italian writers of that time 'il Signor Astone' (see my 'Examen Critique
de l'Hist. de la GÂographie', t. v., p. 80). All the hypotheses that have
been advanced to show that Descartes (Cassini, p. 230; Mairan, p. 16), and
even Kepler (Delambre, t. i., p. 601), were acquainted with the zodiacal
light, appear to me altogether untenable. Descartes ('Principes', iii.,
art. 136, 137) is very obscure in his remarks on comets, observing that
their tails are formed "by oblique rays, which, falling on different parts
of the planetary orbs, strike the eye laterally by extraordinary
refraction," and that they might be seen morning and evening, "like a long
beam," when the Sun is between the comet and the Earth. This passage no
more refers to the zodiacal light than those in which Kepler ('Epit. Astron.
Copernican¾', t. i., p. 57, and t. ii., p. 893) speaks of the existence of
a solar atmosphere (limbus circa solem, coma lucida), which, in eclipses of
the Sun, prevents it "from being quite night:" and even more uncertain, or
indeed erroneous, is the assumption that the "trabes quas [Greek word]
vocant" (Plin., ii., 26 and 27) had reference to the tongue-shaped rising
zodiacal light, as Cassini (p. 231, art. xxxi.) and Mairan (p. 15) have
maintained. Every where among the ancients the trabes are associated with
the bolides (ardores et faces) and other fiery meteors, and even with
long-barbed comets. (Regarding [Greek words] . see SchÂfer, 'Schol. Par.
ad Apoll. Rhod.', 1813, t. ii., p. 206; Pseudo-Aristot., 'de Mundo, 2, 9;
'Comment. Alex. Joh. Philop. et Olymp. in Aristot. Meteor.', lib. i., cap.
vii., 3, p. 195, Ideler; Seneca, 'Nat. Qu¾st.', i., 1.)
We may conjecture, with much probability, that the remarkable light on the
elevated plains of Mexico, seen for forty nights consecutively i8n 1509, and
observed in the eastern horizon rising pyramidally from the earth, was the
zodiacal light. I found a notice of this phenomenon in an ancient Aztec
MS., the 'CodexTelleriano-Remensis',* preserved in the Royal Library at
Paris.
[footnote] *Humboldt, 'Monumens des Peuples IndigÂnes de l'AmÂrique', t.
ii., p. 301. The rare manuscript which belonged to the Archbishop of
Rheims, Le Tellier, contains various kinds of extracts from an Aztec ritual,
an astrological calendar, and historical annals, extending from 1197 to
1549, and embracing a notice of different natural phenomena, epochs of
earthquakes and comets (as, for instance, those of 1490 and 1529), and of
(which are important in relation to Mexican chronology) solar eclipses. In
Camargo's manuscript 'Historia de Tlascala', the light rising in the east
almost to the zenith is, singularly enough, described as "sparkling, and as
if sown with stars." The description of this phenomenon, which lasted forty
days, can not in any way apply to volcanic eruptions of Popcatepetl, which
lies very near, in the southeastery direction. (Prescott, 'History of the
Conquest of Mesico', vol. i., p. 284.) Later commentators have confounded
this phenomenon, which Montezuma regarded as a warning of his misfortunes,
with the "estrella que humeava" (literally, 'which spring forth'; Mexican
'choloa, to leap or spring forth'). With respect to the connection of this
vapor with the star Citlal Choloha (Venus) and with "the mountain of the
star" (Citialtepetl, the volcano of Orizaba), see my 'Monumens', t. ii., p.
303.
This phenomenon, whose primordial antiquity can scarcely be doubted, and
which was first noticed in Europe by Childrey and Dominicus Cassini, is not
the luminous solar atmosphere itself, since this can not, in accordance with
mechanical laws, be more compressed than in the relation of 2 to 3, and
consequently can not be diffused beyond 9/20ths of Mercury's heliocentric
distance. These same laws teach us that the altitude of the extreme
boundaries of the atmosphere of a cosmical
p 141
body above its equator, that is to say, the point at which gravity and
centrifugal force are in equilibrium, must be the same as the altitude at
which a satellite would rotate round the central body simultaneously with
the diurnal revolution of the latter.*
[footnote] *Laplace, 'Expos. du Syst. du Monde', p. 270; 'MÂcanique
CÂleste', t. ii., p. 169 and 171; Schubert, 'Astr.', bd. iii., ¤ 206.
This limitation of the solar atmosphere in its present concentrated
condition is especially remarkable when we compare the central body of our
system with the nucleus of other nebulous stars. Herschel has discovered
several, in which the radius of the nebulous matter surrounding the star
appeared at an angle of 150". On the assumption that the parallax is not
fully equal to 1", we find that the outermost nebulous layer of such a star
must be 150 times further from the central body than our Earth is from the
Sun. If, therefore, the nebulous star were to occupy the place of our Sun,
its atmosphere would not only include the orbit of Uranus, but even extend
eight times beyond it.Â¥
[footnote] *Arago, in the 'Annuaire', 1842, p. 408. Compare Sir John
Herschel's considerations on the volume and faintness of light of planetary
nebul¾, in Mary Somerville's 'Connection of the Physical Sciences', 1835,
p. 108. The opinion that the Sun is a nebulous star, whose atmosphere
presents the phenomenon of zodiacal light, did not originate with Dominicus
Cassini, but was first promulgated by Mairan in 1730 ('Trait de l'Aurore
Bor.', p. 47 and 263; Arago, in the 'Annuaire', 1842, p. 412). It is a
renewal of Kepler's views.
Considering the narrow limitation of the Sun's atmosphere, which we have
just described, we may with much probability regard the existence of a very
compressed annulus of nebulous matter,* revolving freely in space between
the orbits of Venus and Mars, as the material cause of the zodiacal light.
[footnote] *Cominicus Cassini was the first to assume, as did subsequently
Laplace, Schubert, and Poisson, the hypothesis of a separate ring to explain
the form of the zodiacal light. He says distinctly, "If the orbits of
Mercury and Venus were visible (throughout their whole extent), we should
invariably observe them with the same figure and in the same position with
regard to the Sun, and at the same time of the year with the zodiacal
light." ('MÂm. de l'Acad.', t. viii., 1730, p. 218, and Biot, in the
'Comptes Rendus', 1836, t. iii., p. 666.) Cassini believed that the
nebulous ring of zodiacal light consisted of innumerable small planetary
bodies revolving round the Sun. He even went so far as to believe that the
fall of fire-balls might be connected with the passage of the Earth through
the zodiacal nebulous ring. Olmsted, and especially Biot (op. cit., p.
673), have attempted to establish its connection with the November
phenomenon -- a connection which Olbers doubts. (Schum., 'Jahrb.', 1837, s.
281.) Regarding the question whether the place of the zodiacal light
perfectly coincides with that of the Sun's equator, see Houzeau, in Schum.,
'Astr. Nachr.', 1843, No. 492, s. 190.
As
p 142
yet we certainly know nothing definite regarding its actual material
dimensions; its augmentation* by emanations from the tails of myriads of
comets that come within the Sun's vicinity; the singular changes affecting
its expansion, since it sometimes does not apper to extend beyond our
Earth's orbit; or, lastly, regarding its conjectural intimate connection
with the more condensed cosmical vapor in the vicinity of the Sun.
[footnote] *Sir John Herschel, 'Astron.', ¤ 487.
The nebulous particles composing this ring, and revolving round the sun in
accordance with planetary laws, may either be self-luminous or receive light
from that luminary. Even in the case of a terrestrial mist (and this fact
is very remarkable), which occurred at the time of the new moon at midnight
in 1743, the phosphorescence was so intense that objects could be distinctly
recognized at a distance of more than 600 feet.
I have occasionally been astonished in the tropical climates of south
america, to observe the variable intensity of the zodiacal light. As i
passed the nights, during many months, in the open air, on the shores of
rivers and on ilanos, i enjoyed ample opportunities of carefully examining
this phenomenon. When the zodiacal light had been most intense, i have
observed that it would be perceptibly weakened for a few minutes, until it
again suddenly shone forth in full brilliancy. In some few instances i have
thought that i could perceive -- not exactly a reddish coloration, nor the
lower portion darkened in an arc-like form, nor even a scintillation, as
mairan affirms he has observed -- but a kind of flickering and wavering of
the light.*
[footnote] *Arago, in the 'Annuaire', 1832, p. 246. Several physical facts
appear to indicate that, in a mechanical separation of matter into its
smallest particles, if the mass be very small in relation to the surface,
the electrical tension may increase sufficiently for the production of light
and heat. Experiments with a large concave mirror have not hitherto given
any positive evidence of the presence of radiant heat in the zodiacal light.
(Lettre de M. Matthiessen  M. Arago, in the 'Comptes Rendus', t. xvi.,
1843, Avril, p. 687.)
Must we suppose that changes are actually in progress in the nebulous ring?
or is it not more probable that, although I could not, by my meteorological
instruments, detect any change of heat or moisture near the ground, and
small stars of the fifth and sixth magnitudes appeared to shine with equally
undiminished intensity of light, processes of condensation may be going on
in the uppermost strata of the air, by means of which the transparency, or
rather, the reflection of light, may be modified in some peculiar and
unknown manner?
p 143
An assumption of the existence of such meteorological causes on the confines
of our atmosphere is strengthened by the "sudden flash and pulsation of
light," which, according to the acute observations of Olbers, vibrated for
several seconds through the tail of a comet, which appeared during the
continuance of the pulsations of light to be lengthened by several degrees,
and then again contracted.*
[footnote] *"What you tell me of the changes of light in the zodiacal
light, and of the causes to which you ascribe such changes within the
tropics, is of the greatr interest to me, since I have been for a long time
past particularly attentive, every spring, to this phenomenon in our
northern latitudes. I, too, have always believed that the zodiacal light
rotated; but I assumed (contrary to Poisson's opinion, which you have
communicated to me) that it completely extended to the Sun, with
considerably augmenting brightness. The light circle which, in total solar
eclipses, is seen surrounding the darkened Sun, I have regarded as the
brightest portion of the zodiacal light. I have convinced my self that this
light is very different in different years, often for several successive
years being very bright and diffused, while in othr years it is scarcely
perceptible. I tyhink that I find the first trace of an allusion to the
zodiacal light in a letter from Rothmann to Tycho, in which he mentions that
in the spring he has observed the twilight did not close until the sun was
24¼degrees below the horizon. Rothmann must certainly have confounded the
disappearance of the setting zodiacal light in the vapors of the western
horizon with the actual cessation of twilight. I have failed to observe the
pulsations of the light, probably on account of the faintness with which it
appears in these countries. You are, however, certainly right in ascribing
those rapid variations in the light of the heavenly bodies, which you have
perceived in tropical climates, to our own atmosphere, and especially to its
higher regions. This is especially in the clearest weather, that these
tails exhibit pulsations, commencing from the head, as being the lowest
part, and vibrating in one or two seconds through the entire tail, which
thus appears rapidly to become some degrees longer, but again as rapidly
contracts. That these undulations, which were formerly noticed with
attention by Robert Hooke, and in more recent times by SchrÂter and
Chladni, 'do not actually occur in the tails of the comets', but are
produced by our atmosphere, is obvious when we recollect that the individual
parts of those tails (which are many millions of miles in length) lie 'at
very different distances' from us, and that the light from their extreme
points can only reach us at intervals of time which differ several minutes
from one another. Whether what you saw on the Orinoco, not at intervals of
seconds, but of minutes, were actual coruscations of the zodiacal light, or
whether they belonged exclusively to the upper strata of our atmosphere, I
will not attempt to decide; neither can I explain the remarkable 'lightness
of whole nights', nor the anomalous augmentation and prolongation of the
twilight in the year 1831, particularly if, as has been remarked, the
lightest part of these singular twilights did not coincide with the Sun's
place below the horizon." (From a lettr written by Dr. Olbers to myself,
and dated Bremen, Marth 26th, 1833.)
As, however, the separate particles of a comet's tail, measuring millions of
miles,
p 144
are very unequally distant from earth, it is not possible, according to the
laws of the velocity and transmission of light, that we should be able, in
so short a period of time, to perceive any actual changes in a cosmical body
of such vast extent. There considerations in no way exclude the realith of
the changes that have been observed in the emanations from the more
condensed envelopes around the nucleus of a comet, nor that of the sudden
irradiation of the zodiacal light, from internal molecular motion, nor of
the increased or diminished reflection of light in the cosmical vapor of the
luminous ring, but should simply be the means of drawing our attention to
the differences existing between that which appertains to the air of heaven
(the realms of universal space) and that which belongs to the strata of our
terrestrial atmosphere. It is not possible, as well-attested facts prove,
perfectly to explain the operations at work in the much-contested upper
boundaries of our atmosphere. The extraordinary lightness of whole nights
in the year 1831, during which small print might be read at midnight in the
latitudes of Italy and the north of Germany is a fact directly at variance
with all that we know, according to the most recent and acute researches on
the crepuscular theory, and of the height of the atmosphere.*
[footnote] *Biot, 'Trait d'Astron. Physique', 3Âme Âd., 1841, t. i., p.
171, 238 and 312.
The phenomena of light depend upon conditions still less understood, and
their variability at twilight, as well as in the zodiacal light, excite our
astonishment.
We have hitherto considered that which belongs to our solare system -- that
world of material forms governed by the Sun -- which includes the primary
and secondary planets, comets of short and long periods of revolution,
meteoric asteroids, which move thronged together in streams, either
sporadically or in closed rings, and finally a luminous nebulous ring, that
revolves round the Sun in the vicinity of the Earth, and for which, owing to
its position, we may retain the name of zodiacal light. Every where the law
of periodicity governs the motions of these bodies, however different may be
the amount of tangential velocity, or the quantity of their agglomerated
material parts; the meteoric asteroids which enter our atmosphere from the
external regions of universal space are alone arrested in the course of
their planetary revolution, and retained within the sphere of a larger
planet. In the solar system, whose boundaries determine the attractive
force of the central body, comets are made to revolve in their elliptical
p 145
orbits at a distance 44 times greater than that of Uranus; may, in those
comets whose nucleus appears to us, from its inconsiderable mass, like a
mere passing cosmical cloud, the Sun exercises its attractive force on the
outermost parts of the emanations radiating from the tail over a space of
many millions of miles. Central forces, therefore, at once constitute and
maintain the system.
Our Sun may be considered as at rest when compared to all the large and
small, dense and almost vaporous cosmical bodies tht appertain to and
revolve around it; but it actually rotates around the common center of
gravity of the whole system, which occasionally falls within itself, that is
to say, remains within the material circumference of the Sun, whatever
changes may be assumed by the position of the planets. A very different
phenomenon is that presented by the translatory motion of the Sun, that is,
the progressive motion of the center of gravity of the whole solar system in
universal space. Its velocity is such* that, according to Bessel, the
relative motion of the Sun, and that of 61 Cygni, is not less in one day
than 3,336,000 geographical miles.
[footnote] *Bessel, in Schum., 'Jahrb. fÂr' 1839, s. 51; probably four
millions of miles daily, in a relative velocity of at the least 3,336,000
miles, or more than couble the velocity of revolution of the Earth in her
orbit round the Sun.
This change of the entire solar system would remain unknown to us, if the
admirable exactness of our astronomical instruments of measurement, and the
advancement recently made in the art of observing, did not cause our advance
toward remote stars to be perceptible, like an approximation to the objects
of a distant shore in apparent motion. The proper motion of the star 61
Cygni, for instance, is so considerable, that it has amounted to a whole
degree in the course of 700 years.
The amount or quantity of these alterations in the fixed stars (that is to
say, the changes in the relative position of self-luminous stars toward each
other), can be determined with a greater degree of certainty than we are
able to attach to the genetic explanation of the phenomenon. After taking
into consideration what is due to the precession of the equinoxes, and the
nutation of the earth's axis produced by the action of the Sun and Moon on
the spheroidal figure of our globe, and what may be ascribed to the
transmission of light, that is to say, to its aberration, and to the
parallax formed by the diametrically opposite position of the Earth in its
course round the Sun, we still find that there is a residual portion
p 146
of the annual motion of the fixed stars due to the translation of the whole
solar system in universal space, and to the true proper motion of the stars.
The difficult problem of numerically separating these two elements, the
true and the apparent motion, has been effected by the careful study of the
direction of the motion of certain individual stars, and by the
consideration of the fact that, if all the stars were in a state of absolute
rest, they would appear perspectively to recede from the point in space
toward which the Sun was directing its course. But the ultimate result of
this investigation, confirmed by the calculus of probabilities, is, that our
solar system and the stars both change their places in space. According to
the admirable researches of d'Argelander at Abo, who has extended and more
perfectly developed the work begun by William Herschel and Prevost, the Sun
moves in the direction of the constellation Hercules, and probably, from the
combination of the observations made of 537 stars, toward a point lying (at
the equinox of 1792.5) at 257¼degrees 49.'7 R.A., and 28¼degrees 49.'7
N.D. It is extremely difficult, in investigations of this nature, to
separate the absolute from the relative motion, and to determine what is
aloone owing to the solar system.*
[footnote] *Regarding the motion of the solar system, according to Bradley,
Tobias Mayer, Lambert, Lalande, and William Herschel, see Arago in the
'Annuaire', 1842, p. 388-399' Argelander, in Schum., 'Astron. Nachr
., No. 363, 364, 398, and in the treatise 'Von der eigenen Bewegung des
Sonnensystems' (On the proper Motion of the Solar System), 1837, s. 43,
respecting Perseus as the central body of the whole stellar stratum,
likewise Otho Struve, in the 'Bull. de l'Acad. de St. PÂtersb.', 1842, t.
x., No. 9, p. 137-139. The last-named astronomer has found, by a mo4re
recent combination, 261¼degrees 23' R.A.+37¼degrees 36' Decl. for the
direction of the Sun's motion; and, taking the mean of his own results with
that of Argelander, we have, by a combination of 797 stars, the formula
259¼degrees 9' R.A.+34¼degrees 36' Decl.
If we consider the proper, and not the perspective motions of the stars, we
shall find many that appear to be distributed in groups, having an opposite
direction; and facts hitherto observed do not, at any rate, render it a
necessary assumption that all parts of our starry stratum, or the whole of
the stellar islands filling space, should move round one large unknown
luminous or non-luminous central body. The tendency of the human mind to
investigate ultimate and highest causes certainly inclines the intellectual
activity, no less than the imagination of mankind, to adopt such an
hypothesis. Even the Stagirite proclaimed that "every thing which is moved
must be referable to a motor, and that there would be no end to
p 147
the concatenation of causes if there were not one primordial immovable
morot."*
[footnote] *Aristot., 'de C¾lo', iii., 2, p. 301, Bekker: 'Phys.', viii.,
t, p. 256.
This material taken from pages 147-203
COSMOS: A Sketch of the Physical Description of the Universe, Vol. 1
by Alexander von Humboldt
Translated by E C Otte
from the 1858 Harper & Brothers edition of Cosmos, volume 1
--------------------------------------------------
The manifold translatory changes of the stars, not those produced by the
parallaxes at which they are seen from the changing position of the
spectator, but the true changes constantly going on in the regions of space,
afford us incontrovertible evidence of the 'dominion of the laws of
attraction' in the remotest regions of space, beyond the limits of our solar
system. The existence of these laws is revealed to us by many phenomena,
as, for instance, by the motion of double stars, and by the amount of
retarded or accelerated motion in different parts of their elliptic orbits.
Human inquiry need no longer pursue this subject in the domain of vague
conjecture, or amid the undefined analogies of the ideal world; for even
here the progress made in the method of astronomical observations and
calculations has enabled astronomy to take up its position on a firm basis.
It is not only the discovery of the astounding numbers of double and
multiple stars revolving round a center of gravity lying 'without' their
system (2800 such systems having been discovered up to 1837), but rather the
extension of our knowledge regarding the fundamental forces of the whole
material world, and the proofs we have obtained of the universal empire of
the laws of attraction, that must be ranked among the most brilliant
discoveries of the age. The periods of revolution of colored stars present
the greatest differences; thus, in some instances, the period extends to 43
years, as in ¹pi of Corona, and in others to several thousands,, as in 66
of Cetus, 38 of Gemini, and 100 of Pisces. Since Herschel's measurements in
1782, the satellite of the nearest star in the triple system of [Greek
letter] of Cancer has completed more than one entire revolution. By a
skillful combination of the altered distances and angles of position,* the
elements of these orbits may be found, conclusions drawn regarding the
absolute distance of the double stars from the Earth, and comparisons made
between their mass and that of the Sun.
[footnote] *Savary, in the 'Connaissance des Tems', 1830, p. 56 and 163.
Encke, 'Berl. Jahrb.', 1832, s. 253, etc. Arago, in the 'Annuaire' 1834, p.
260, 295. John Herschel, in the 'Memoirs of the Astronom. Soc.', vol. v.,
p. 171.
Whether, however, here and in our solar system, quantity of matter is the
only standard of the amount of attractive force, or whether 'specific'
forces of attraction proportionate to the mass may not at the same time come
into operation, as Bessel was the first to conjecture, are questions
p 148
whose practical solution must be left to future ages.*
[footnote] * Bessel, 'Untersuchung. des Theils der planetarischen
Storungen, welche aus der Bewegung der Sonne entstchen' (An Investigation of
the portion of the Planetary Disturbances depending on the motion of the
Sun) in 'Abh. der Berl. Akad. der Wissensch.', 1824 (Mathem. Classe), s.
2-6. The question has been raised by John Tobias Mayer, in 'Comment. Soc.
Reg. Gotting.', 1804-1808, vol. xvi., p. 31-68.
When we compare our Sun with the other fixed stars, that is, with other
self-luminous Suns in the lenticular starry stratum of which our system
forms a part, we find, at least in the case of some, that channels are
opened to us, which may lead, at all events, to an 'approximate' and limited
knowledge of their relative distances, volumes, and masses, and of the
velocities of their translatory motion. If we assume the distance of Uranus
from the Sun to be nineteen times that of the Earth, that is to say,
nineteen times as great as that of the Sun from the Earth, the central body
of our planetary system will be 11,900 times the distance of Uranus from the
star 'a' in the constellation Centaur, almost 31,300 from 61 Cygni, and
41,600 from Vega in the constellation Lyra. The comparison of the volume of
the Sun with that of the fixed stars of the first magnitude is dependent
upon the apparent diameter of the latter bodies -- an extremely undertain
optical element. If even we assume, with Herschel, that the apparent
diameter of Arcturus is only a tenth part of a second, it still follows that
the true diameter of this star is eleven times greater than that of the Sun.*
[footnote] *'Philos. Trans.' for 1803, p. 225. Arago, in the 'Annuaire',
1842, p. 375. In order to obtain a clearer idea of the distances ascribed
in a rather earlier part of the text to the fixed stars, let us assume that
the Earth is a distance of one foot from the Sun; Uranus is then 19 feet,
and Vega Lyrae is 158 geographical miles from it.
The distance of the star 61 Cygni, made known by Bessel, has led
approximately to a knowledge of the quantity of matter contained in this
body as a double star. Notwithstanding that, since Bradley's observations,
the portion of the apparent orbit traversed by this star is not sufficiently
great to admit of our arriving with perfect exactness at the true orbit nd
the major axis of this star, it has been conjectured with much probability
by the great Konigsberg astronomer,* "that the mass of this double star can
not be very considerably larger or smaller than half of the mass of the
Sun."
[footnote] *Bessel, in Schum., 'Jahrb.', 1839, s. 53.
This result is from actual measurement. The analogies deduced from the
relatively larger mass of those planets in our solar system that are
attended by satellites, and from the fact that Struve has discovered six
times more double stars among
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the brighter than among the telescopic fixed stars, have led other
astronomers to conjecture that the average mass of the larger number of the
binary stars exceeds the mass of the Sun.*
[footnote] *MÂdler, 'Astron.', s. 476; also in Schum, 'Jahrb.', 1839, s.
95.
We are, however, far from having arrived at general results regarding this
subject. Our Sun, according to Argenlander, belongs, with reference to
proper motion in space, to the class of rapidly-moving fixed stars.
The aspect of the starry heavens, the relative position of stars and
nebullae, the distribution of their luminous masses, the picturesque beauty,
if I may so express myself, of the whole firmament, depend in the course of
ages conjointly upon the proper motion of the stars and nebulae, the
translation of our solar system in space, the appearance of new stars, and
the disappearance or sudden diminution in the intensity of the light of
others, and lastly and specially, on the changes which the Earth's axis
experiences from the attraction of the Sun and Moon. The beautiful stars in
the constellation of the Centaur and the Southern Cross will at some future
time be visible in our northern latitudes, while other stars, as Sirius and
the stars in the Belt of Orion, will in their turn disappear below the
horizon. The places of the North Pole will successively be indicated by the
stars § beta and a alpha Cephei, and ¶ delta Cygni, until after a period
of 12,000 years, Vega in Lyra will shine forth as the brightest of all
possible pole stars. These data give us some idea of the extent of the
motions which, divided into infinitely small portions of time, proceed
without intermission in the great chronometer of the universe. If for a
moment we could yield to the power of fancy, and imagine the acuteness of
our visual organs to be made equal with the extremest bounds of telescopic
vision, and bring together that which is now divided by long periods of
time, the apparent rest that reigns in space would suddenly disappear. We
should see the countless host of fixed stars moving in thronged groups in
different directions; nebulae wandering through space, and becoming
condensed and dissolved like cosmical clouds; the vail of the Milky Way
separated and broken up in many parts, and 'motion' ruling supreme in every
portion of the vault of heave, even as on the Earth's surface, where we see
it unfolded in the germ, the leaf, and the blossom, the organisms of the
vegetable world. The celebrated Spanish botanist Cavanilles was the first
who entertained the idea of "seeing grass grow," and he directed the
horizontal micrometer threads of a powerfully magnifying glass at one time to
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the apex of the shoot of a bambusa, and at another on the rapidly-growing
stem of an American aloe ('Agave Americana', precisely as the astronomer
places his cross of net-work against a culminating star. In the collective
life of physical nature, in the organic as in the sidereal world, all things
that have been, that are, and will be, are alike dependent on motion.
The breaking up of the Milky Way, of which I have just spoken, requires
special notice. William Herschel, our safe and admirable guide to this
portion of the regions of space, has discovered by his star-guagings that
the telescopic breadth of the Milky Way extends from six to seven degrees
beyond what is indicated by our astronomical maps and by the extent of the
sidereal radiance visible to the naked eye.*
[footnote] *Sir William Herschel, in the 'Philos. Transact.' for 1817, Part
ii p. 438.
The two brilliant nodes in which the branches of the zone unite, in the
region of Cepheus and Cassiopeia, and in the vicinity of Scorpio and
Sagittarius, appear to exercise a powerful attraction on the contiguous
stars; in the most brilliant part, however between beta and [Greek symbol]
Cygni, one half of the 330,000 stars that have been discovered in a breadth
of 5 degrees are directed toward one side, and the remainder to the other.
It is in this part that Herschel supposes the layer to be broken up.*
[footnote] *Arago, in the 'Annuaire', 1842, p. 569
The number of telescopic stars in the Milky Way uninterrupted by any nebulae
is estimated at 18 millions. In order, I will not say, to realize the
greatness of this number, but, at any rate, to compare it with something
analogous, I will call attention to the fact that there are not in the whole
heavens more than about 8000 stars between the first and the sixth
magnitudes, visible to the naked eye. The barren astonishment excited by
numbers and dimensions in space, when not considered with reference to
applications engaging the mental and perceptive powers of man, is awakened
in both extremes of the universe, in the celestial bodies as in the minutest
animalcules.*
[footnote] *Sir John Herschel, in a letter from Feldhuysen, dated Jan.
13th, 1836. Nicholl, 'Architecture of the Heavens', 1838, p. 22. (See,
also, some separate notices by Sir William Herschel on the starless space
which separates us by a great distance from the Milky Way, in the 'Philos.
Transact.' for 1817, Part ii., p. 328.)
A cubic inch of the polishing slate of Bilin contains, according to
Ehrenberg, 40,000 millions of the silicious shells of Galionellae.
The stellar Milky Way, in the region of which, according to Argelander's
admirable observations, the brightest stars of the firmament appear to be
congregated, is almost at right angles
p 151
with another Milky Way, composed of nebulae. The former constitutes,
according to Sir John Herschel's views, an annulus, that is to say, an
independent zone, somewhat remote from our lenticular-shaped starry stratum,
and similar to Saturn's ring. Our planetary system lies in an eccentric
direction, nearer to the region of the Cross than to the diametrically
opposite point, Cassiopeia.*
[footnote] *Sir John Herschel, 'Astronom.', 624; likewise in his
'Observations on Nebulae and Clusters of Stars' ('Phil. Transact.', 1833,
Part ii., p. 479, fig. 25): "We have here a brother system, bearing a real
physical resemblance and strong analogy of structure to our own."
An imperfectly seen nebulous spot, discovered by Messier in 1774, appeared
to present a remarkable similarity to the form of our starry stratum and the
divided ring of our Milky Way.*
[footnote] *Sir William Herschel, in the 'Phil. Trans.' for 1785, Part i.,
p. 257. Sir John Herschel, 'Astron.', 616. ("The 'nebulous' region of the
heavens forms 'a nebulous Milky Way', composed of distinct nebulae, as the
other of stars." The same observation was made in a letter he addressed to
me in March, 1829.)
The Milky Way composed of nebulae does not belong to our starry stratum, but
surrounds it at a great distance without being physically connected with it,
passing almost in the form of a large cross through the dense nebulae of
Virgo, especially in the northern wing, through Comae Berenicis, Ursa Major,
Andromeda's girdle, and Pisces Boreales. It probably intersects the stellar
Milky Way in Cassiopeia, and connects its dreary poles (rendered starless
from the attractive forces by which stellar bodies are made to agglomerate
into groups) in the least dense portion of the starry stratum.
We see from these considerations that our starry cluster, which bears traces
in its projecting branches of having been subject in the course of time to
various metamorphoses, and evinces a tendency to dissolve and separate,
owing to secondary centers of attraction -- is surrounded by two rings, one
of which, the nebulous zone, is very remote, while the other is nearer, and
composed of stars alone. The latter, which we generally term the Milky Way,
is composed of nebulous stars, averaging from the tenth to the eleventh
degree of magnitude,* but appearing, when considered individually, of very
different magnitudes, while isolated starry clusters (starry swarms) almost
always exhibit throughout a character of great uniformity in magnitude and
brilliancy.
[footnote] *Sir John Herschel, 'Astron.', 585.
In whatever part the vault of heaven has been pierced by powerful and
far-penetrating telescopic instruments, stars or luminous nebulae are every
where discoverable, the former, in
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some cases, not exceeding the twentieth or twenty-fourth degree of
telescopic magnitude. A portion of the nebulous vapor would probably be
found resolvable into stars by more powerful optical instruments. As the
retina retains a less vivid impression of separate than of infinitely near
luminous points, less strongly marked photometric relations are excited in
the latter case, as Arago has recently shown.*
[footnote] *Arago, in the 'Annuaire', 1842, p. 282-285, 409-411, and
439-442.
The definite or amorphous cosmical vapor so universally diffused, and which
generates heat through condensation, probably modifies the transparency of
the universal atmosphere, and diminishes that uniform intensity of light
which, according to Halley and Olbers, should arise, if every point
throughout the depths of space were filled by an infinite series of stars.*
[footnote] *Olbers, on the transparency of celestial space, in Bode's
'Jahrb.', 1826, s. 110-121.
The assumption of such a distribution in space is, however, at variance with
observation, which shows us large starless regions of space, 'openings' in
the heavens, as William Herschel terms them -- one, four degrees in width,
in Scorpio, and another in Serpentarius. In the vicinity of both, near
their margin, we find unresolvable nebulae, of which that on the western
edge of the opening Scorpio is one of the most richly thronged of the
clusters of small stars by which the firmament is adorned. Herschel
ascribes these openings or starless regions to the attractive and
agglomerative forcesof the marginal groups.*
[footnote] *"An opening in the heavens," William Herschel, in the 'Phil.
Trans.' for 1785, vol. lxxv., Part i., p. 256. Le Francais Lalande, in the
'Connaiss. des Tems pour l'An.' VIII., p. 383. Arago, in the 'Annuaire',
1842, p. 425.
"They are parts of our starry stratum," says he, with his usual graceful
animation of style, "that have experienced great devastation from time." If
we picture to ourselves the telescopic stars lying behind one another as a
starry canopy spread over the vault of heaven, these starless regions in
Scorpio and Serpentarius may, I think, be regarded as tubes through which we
may look into the remotest depths of space. Other stars may certainly lie
in those parts where the strata forming the canopy are interrupted, but
these are unattainable by our instruments. The aspect of fiery meteors had
led the ancients likewise to the idea of clefts or openings ('chasmata') in
the vault of heaven. These openings were, however, only regarded as
transient, while the reason of their being luminous and fiery, instead of
obscure, was supposed to be owing to the
p 153
translucent illuminated ether which lay beyond them.*
[footnote] *Aristot., 'Meteor.', ii.,, 5, 1. Seneca, 'Natur. Quaest.', i.,
14, 2. "Coelum discessisse," in Cic., 'de Divin.', i., 43.
Derham, and even Huygens, did not appear disinclined to explain in a similar
manner the mild radiance of the nebulae.*
[footnote] *Arago, in the 'Annuaire', 1842, p. 429.
When we compare the stars of the first magnitude, which, on an average, are
certainly the nearest to us, with the non-nebulous telescopic stars, and
further, when we compare the nebulous stars with unresolvable nebulae, for
instance, with the nebula in Andromeda, or even with the so-called planetary
nebulous vapor, a fact is made manifest to us by the consideration of the
varying distances and the boundlessness of space, which shows the world of
phenomena, and that which constitutes its causal reality, to be dependent
upon the 'propagation of light'. The velocity of this propagation is
according to Struve's most recent investigations, 166,072 geographical miles
in a second, consequently almost a million of times greater than the
velocity of sound. According to the measurements of Maclear, Bessel, and
Struve, of the parallaxes and distances of three fixed stars of very unequal
magnitudes ('a' Centauri, 16 Cygni, and 'a' Lyrae), a ray of light requires
respectively 3, 9 1/4, and 12 years to reach us from these three bodies. In
the short but memorable period between 1572 and 1604, from the time of
Cornelius Gemma and Tycho Brahe to that of Kepler, three new stars suddenly
appeared in Cassiopeia and Cygnus, and in the foot of Serpentarius. A
similar phenomenon exhibited itself at intervals in 1670, in the
constellation Vulpis. In recent times, even since 1837, Sir John Herschel
has observed, at the Cape of Good Hope, the brilliant star [Greek symbol] in
Argo increase in splendor from the second to the first magnitude.*
[footnote] *In December, 1837, Sir John Herschel saw the star [Greek
symbol] Argo, which till that time appeared as of the second magnitude, and
liable to no change, rapidly increase till it became of the first magnitude.
In January, 1838, the intensity of its light was equal to that of 'a'
Centauri. According to our latest information, Maclear in March, 1843,
found it as bright as Canopus; and even 'a' Crucis looked faint by [Greek
symbol] Argo.
These events in the universe belong, however, with reference to their
historical reality, to other periods of time than those in which the
phenomena of light are first revealed to the inhabitants of the Earth: they
reach us like the voices of the past. It has been truly said, that with our
large and powerful telescopic instruments we penetrate alike through the
boundaries of time and space: we measure the former through the latter, for
in the course of an
p 154
hour a ray of light traverses over a space of 592 millions of miles. While
according to the theogony of Hesiod, the dimensions of the universe were
supposed to be expressed by the time occupied by bodies in falling to the
ground ("the brazen anvil was not more than nine days and nine nights in
falling from heaven to earth"), the elder Herschel was of opinion* that
light required almost two millions of years to pass to the Earth from the
remotest luminous vapor reached by his forty-foot reflector.
[footnote] *"Hence it follows that the rays of light of the remotest
nebulae must have been almost two millions of years on their way, and that
consequently, so many years ago, this object must already have had an
existence in the sidereal heaven, in order to send out those rays by which
we now perceive it." William Herschel, in the 'Phil. Trans.' for 1802, p.
498. John Herschel, 'Astron.', 590. Arago, in the 'Annuaire', 1842, p.
334, 359, and 382-385.
Much, therefore, has vanished long before it is rendered visible to us --
much that we see was once differently arranged from what it now appears.
The aspect of the starry heavens presents us with the spectacle of that
which is only apparently simultaneous, and however much we may endeavor, by
the aid of optical instruments, to bring the mildly-radiant vapor of
nebulous masses or the faintly-glimmering starry clusters nearer, and
diminish the thousands of years interposed between us and them, that serve
as a criterion of their distance, it still remains more than probable, from
the knowledge we possess of the velocity of the transmission of luminous
rays, that the light of remote heavenly bodies presents us with the most
ancient perceptible evidence of the existence of matter. It is thus that
the reflective mind of man is led from simple premises to rise to those
exalted heights of nature, where in the light-illumined realms of space,
"myriads of worlds are bursting into life like the grass of the night."*
[fotnote] *From my brother's beautiful sonnet "Freiheit und Gesetz."
(Wilhelm von Humboldt, 'Gesammelte Werke', bd. iv., s. 358, No. 25.)
From the regions of celestial forms, the domain of Uranus, we will now
descend to the more contracted sphere of terrestrial forces -- to the
interior of the Earth itself. A mysterious chain links together both
classes of phenomena. According to the ancient signification of the Titanic
myth,* the powers of organic life, that is to say, the great order of
nature, depend upon the combined action of heaven and earth.
[footnote] *Otfried Muller, 'Prolegomena', s. 373.
If we suppose that the Earth, like all the other planets, primordially
belonged, according to its origin, to the central body, the Sun, and to the
solar atmosphere that has been separated into nebulous
p 155
rings, the same connection with this continguous Sun, as well as with all
the remote suns that shine in the firmament, is still revealed through the
phenomena of light and radiating heat. The difference in the degree of
these actions must not lead the physicist, in his delineation of nature, to
forget the connection and the common empire of similar forces in the
universe. A small fraction of telluric heat is derived from the regions of
universal space in which our planetary system is moving, whose temperature
(which according to Fourier, is almost equal to our mean icy polar heat) is
the result of the combined radiation of all the stars. The causes that more
powerfully excite the light of the Sun in the atmosphere and in the upper
strata of our air, that give rise to heat-engendering electric and magnetic
currents, and awaken and genially vivify the vital spark in organic
structures on the earth's surface, must be reserved for the subject of our
future consideration.
As we purpose for the present to confine ourselves exclusively within the
telluric sphere of nature, it will be expedient to cast a preliminary glance
over the relations in space of solids and fluids, the form of the Earth, its
mean density, and the partial distribution of this density in the interior
of our planet, its temperature and its electro-magnetic tension. From the
consideration of these relations in space, and of the forces inherent in
matter, we shall pass to the reaction of the interior on the exterior of our
globe; and to the special consideration of a universally distributed natural
power -- subterranean heat; to the phenomena of earthquakes, exhibited in
unequally expanded circles of commotion, which are not referable to the
action of dynamic laws alone; to the springing forth of hot wells; and,
lastly, to the more powerful actions of volcanic processes. The crust of
the Earth, which may scarcely have been perceptibly elevated by the sudden
and repeated, or almost uninterrupted shocks by which it has been moved from
below, undergoes, nevertheless, great changes in the course of centuries in
the relations of the elevation of solid portions, when compared with the
surface of the liquid parts, and even in the form of the bottom of the sea.
In this manner simultaneous temporary or permanent fissures are opened, by
which the interior of the Earth is brought in contact with the external
atmosphere. Molten masses, rising from an unknown depth, flow in narrow
streams along the declivity of mountains, rushing impetuously onward, or
moving slowly and gently, until the fiery source is quenched in the midst of
exhalations, and the lava becomes incrusted, as it were, by
p 156
the solidification of its outer surface. New masses of rocks are thus
formed before our eyes, while the older ones are in their turn converted
into other forms by the greater or lesser agency of Platonic forces. Even
where no disruption takes place the crystalline moleculres are displaced,
combining to form bodies of denser texture. The water presents structures
of a totally different nature, as, for instance, concretions of animal and
vegetable remains, of earthy, calcareous, or aluminous precipitates,
agglomerations of finely-pulverized mineral bodies, covered with layers of
the silicious shields of infusoria, and with transported soils containing
the bones of fossil animal forms of a more ancient world. The study of the
strata which are so differently formed and arranged before our eyes, and of
all that has been so variously dislocated, conforted, and upheaved, by
mutual compression and volcanic force, leads the reflective observer, by
simple analogies, to draw a comparison between the present and an age that
has long passed. It is by a combination of actual phenomena, by an ideal
enlargement of relations in space, and of the amount of active forces, that
we are able to advance into the long sought and indefinitely anticipated
domain of geognosy, which has only within the last half century been based
on the solid foundation of scientific deduction.
It has been acutely remarked, "that notwithstanding our continual employment
of large telescopes, we are less acquainted with the exterior than with the
interior of other planets, excepting, perhaps, our own satellite." They
have been weighed, and their volume measured; and their mass and density are
becoming known with constantly-increasing exactness; thanks to the progress
made in astronomical observation and calculation. Their physical character
is, however, hidden in obscurity, for it is only in our own globe that we
can be brought in immediate contact with all the elements of organic and
inorganic creation. The diversity of the most heterogenous substances,
their admixtures and metamorphoses, and the ever-changing play of the forces
called into action, afford to the human mind both nourishment and enjoyment,
and open an immeasurable field of observation, from which the intellectual
activity of man derives a great portion of its grandeur and power. The
world of perceptive phenomena is reflected in the depths of the ideal world,
and the richness of nature and the mass of all that admits of classification
gradually become the objects of inductive reasoning.
I would here allude to the advantage, of which I have already
p 157
spoken, possessed by that portion of physical science whose origin is
familiar to us, and is connected with our earthly existence. The physical
description of celestial bodies from the remotely-glimmering nebulae with
their suns, to the central body of our own system, is limited, as we have
seen, to general conceptions of the volume and quantity of matter. No
manifestation of vital activity is there presented to our senses. It is
only from analogies, frequently from purely ideal combinations, that we
hazard conjectures on the specific elements of matter, or on their various
modifications in the different planetary bodies. But the physical knowledge
of the heterogeneous nature of matter, its chemical differences, the regular
forms in which its molecules combine together, whether in crystals or
granules; its relations to the deflected or decomposed waves of light by
which it is penetrated; to radiating, transmitted, or polarized heat; and to
the brilliant or invisible, but not, on that account, less active phenomena
of electro-magnetism -- all this inexhaustible treasure, by which the
enjoyment of the contemplation of nature is so much heightened, is dependent
on the surface of the planet which we inhabit, and more on its solid than on
its liquid parts. I have already remarked how greatly the study of natural
objects and forces, and the infinite diversity of the sources they open for
our consideration, strengthen the mental activity, and call into action
every manifestation of intellectual progress. These relations require,
however, as little comment as that concatenation of causes by which
particular nations are permitted to enjoy a superiority over others in the
exercise of a material power derived from their command of a portion of
these elementary forces of nature.
If, on the one hand, it were necessary to indicate the difference existing
between the nature of our knowledge of the Earth and of that of the
celestial regions and their contents, I am no less desirous, on the other
hand, to draw attention to the limited boundaries of that portion of
spacefrom which we derive all our knowledge of the heterogeneous character
of matter. This has been somewhat inappropriately termed the Earth's crust;
it includes the strata most contiguous to the upper surface of our planet,
and which have been laid open before us by deep fissure-like valleys, or by
the labors of man, in the bores and shafts formed by miners. These labors*
do not extend beyond a vertical depth of somewhat more than 2000 feet (about
one third of a geographical mile) below the
p 159
level of the sea, and consequently only about 1/9800th of the Earth's
radius.
[footnote] *In speaking of the greatest depths within the Earth reached by
human labor, we must recollect that there is a difference between the
'absolute depth' (that is to say, the depth below the Earth's surface at
that point) and the 'relative depth' (or that beneath the level of the sea).
The greatest relative depth that man has hitherto reached is probably the
bore at the new salt-works at Minden, in Prussia: in June, 1814, it was
exactly 1993 feet, the absolute depth being 2231 feet. The temperature of
the water at the bottom was 98 degrees F., which assuming the mean
temperature of the air at 49.3 degrees gives an augmentation of temperature
of 1 degree for every 54 feet. The absolute depth of the Artesian well of
Grenelle, near Paris, is only 1795 feet. According to the account of the
missionary Imbert, the fire-springs, "Ho-tsing." of the Chinese, which are
sunk to obtain [carbureted] hydrogen gas for salt-boiling, far exceed our
Artesian springs in depth. In the Chinese province of Szu-tschuan these
fire-springs are very commonly of the depth of more than 2000 feet; indeed,
at Tseu-lieu-tsing (the place of continual flow) there is a Ho-tsing which,
in the year 1812, was found to be 3197 feet deep. (Humboldt, 'Asie
Centrale', t. ii., p. 521 and 525. 'Annales de l'Association de la
Propagation de la Foi', 1829, No. 16, p. 369.)
[footnote continues] The relative depth reached at Mount Massi, in Tuscany,
south of Volterra, amounts, according to Matteuci, to only 1253 feet. The
boring at the new salt-works near Minden is probably of about the same
relative depth as the coal-mine at Apendale, near Newcastle-under-Lyme, in
Staffordshire, where men work 725 yards below the surface of the earth.
(Thomas Smith, 'Miner's Guide', 1836, p. 160.) Unfortunately, I do not know
the exact height of its mouth above the level of the sea. The relative
depth of the Monk-wearmouth mine, near Newcastle, is only 1496 feet.
(Phillips, in the 'Philos. Mag.', vol. v., 1834, p. 446.) That of the Liege
coal-mine, 'l'Esperance' at Seraing, is, according to M. Gernaert, Ingenieur
des Mines, 1223 feet in depth. The works of greatest absolute depth that
have ever been formed are for the most part situated in such elevated plains
or valleys that they either do not descend so low as the level of the sea,
or at most reach very little below it. Thus the Eselchacht, at Kuttenberg,
in Bohemia, a mine which can not now be worked, had the enormous absolute
depth of 3778 feet. (Fr. A. Schmidt, 'Berggestze der oter Mon.', abth. i.,
bd. i., s. xxxii.) Also, at St. Daniel and at Geish, on the Rorerbubel, in
the 'Landgericht' (or provincial district) of Kitzbuhl, there were, in the
sixteenth century, excavations of 3107 feet. The plans of the works of the
Rorerbubel are still preserved. (See Joseph von Sperges, 'Tyroler
Bergwerksgeschichte', s. 121. Compare, also, Humboldt, 'Gutachten uber
úerantreibung des Meissner Stollens in die Freiberger Erzrevier', printed
in Herder, 'uber Herantreibung des Meissner Stollens in die Freiberger
Erzrevier', printed in Herder, 'uber den jetz begonnenen Erbstollen', 1838,
s. cxxiv.) We may presume that the knowledge of the extraordinary depth of
the Rorerbuhel reached England at an early period, for I find it remarked in
Gilbert, 'de Magnete', that men have penetrated 2400 or even 3000 feet into
the crust of the Earth. ("Exigua videtur terrae portio, quae unquam
hominibus spectanda emerget aut eruitur; cum profundinus in ejus viscera,
ultra efflorescentis extremitatis corruptelam, aut propter aquas in magnis
fodin, tanquam per venas scaturientesaut propter seris salubrioris ad vitam
operariorum sustinendam necessarii defectum, aut propter ingentex sumptus ad
tantos labores exantlandos, multasque difficultates, ad profundiores terrz'
partes penetrre non possumus; adeo ut quadrigentas aut [quod rarissime]
quingentas orgyas in quibusdam metallis descendisse, stupendus omnibus
videatur connatus." -- Guilielmi Gilberti, Colcestrensis, 'de Magnete
Physiologia nova'. Lond., 1600, p. 40.)
[footnote continues] The absolute depth of the mines in the Saxon
Erzgebirge, near Freiburg, are: in the Thurmhofer mines, 1944 feet; in the
Honenbirker mines, 1827 feet; the relative depths are only 677 and 277 feet,
if, in order to calculate the elevation of the mine's mouth above the level
of the sea, we regard the elevation of Freiburg as determined by Reich's
recent observations to be 1269 feet. The absolute depth of the celebrated
mine of Joachimsthal, in Bohemia (Verkreuzung des Jung Hauer Zechen-und
Andreasganges), is full 2120 feet; so that, as Von Dechen's measurements
show that its surface is about 2388 feet above the level of the sea, it
follows that the excavations have not as yet reached that point. In the
Harz, the Samson mine at Andreasberg has an absolute depth of 2197 feet. In
what was formerly Spanish America, I know of no mine deeper than the
Valenciana, near Guanaxuato (Mexico), where I found the absolute depth of
the Planes de San Bernardo to be 1686 feet; but these planes are 5960 feet
above the level of the sea. If we compare the depth of the old Kuttenberger
mine (a depth greater than the height of our Brocken, and only 200 feet less
than that of Vesuvius) with the loftiest structures that the hands of man
have erected (with the Pyramid of Cheops and with the Cathedral of
Strasburg), we find that they stand in the ratio of eight to one. In this
note I have collected all the certain information I could find regarding the
greatest absolute and relative depths of mines and borings. In descending
eastward from Jerusalem toward the Dead Sea, a view presents itself to the
eye, which, according to our present hypsometrical knowledge of the surface
of our planet, is unrivaled in any country; as we approach the open ravine
through which the Jordan takes its course, we tread, with the open sky above
us, on rocks which, according to the barometric measurements of Berton and
Russegger are 1385 feet below the level of the Mediterranean. (Humboldt,
'Asie Centrale', th. ii., p. 323.)
The crystalline masses that have been erupted from active volcanoes, and are
generally similar to the rocks on the upper surface, have come from depths
which, although not accurately determined, must certainly be sixty times
greater than those to which human labor has been enabled to penetrate. We
are able to give in numbers the depth of the shaft where the strata of coal,
after penetrating a certain way, rise again at a distance that admits of
being accurately defined by measurements. These dips show that the
carboniferous strata, together with the fossil organic remains which they
contain, must lie, as, for instance, in Belgium, more than five or six
thousand feet* below the present level
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of the sea, and that the calcareous and the curved strata of the Devonian
basin penetrate twice that depth.
[footnote] *Basin-shaped curved strata, which dip and reappear at
measureable distances, although their deepest portions are beyond the reach
of the miner, afford sensible evidence of the nature of the earth's crust at
great depths below its surface. Testimony of this kind possesses,
consequently, a great geognostic interest. I am indebted to that excellent
geognosist, Von Dechen, for the following observations. "The depth of the
coal basin of Liege, at Mont St. Gilles, which I, in conjunction with our
friend Von Oeynhausen, have ascertained to be 3890 feet below the surface,
extends 3464 feet below the surface of the sea, for the absolute height of
Mont St. Gilles certainly does not much exceed 400 feet; the coal basin of
Mons is fully 1865 feet deeper. But all these depths are trifling compared
with those which are presented by the coal strata of Saar-Revier
(Saarbrucken). I have found after repeated examinations, that the lowest
coal stratum which is known in the neighborhood of Duttweiler, near
Bettingen, northeast of Saarlouis, must descend to depths of 20,682 and
22,015 feet (or 3.6 geographical miles) below the level of the sea." This
result exceeds, by more than 8000 feet, the assumption made in the text
regarding the basin of the Devonian strata. This coal-field is therefore
sunk as far below the surface of the sea as Chimborazo is elevated above it
-- at a depth at which the Earth's temperature must be as high as
435¼degrees F. Hence, from the highest pinnacles of the Himalaya to the
lowest basins containing the vegetation of an earlier world, there is a
vertical distance of about 48,000 feet, or of the 435th part of the Earth's
radius.
If we compare these subterranean basins with the summits of montains that
have hitherto been considered as the most elevated portions of the raised
crust of the Earth, we obtain a distance of 37,000 feet (about seven miles),
that is, about the 1/524th of the Earth's radius. These, therefore, would
be the limits of vertical depth and of the superposition of mineral strata
to which geognostical inquiry could penetrate, even if the general elevation
of the upper surface of the earth were equal to the height of the
Dhawalagigi in the Himalaya, or of the Sorata in Bolivia. All that lies at
a greater depth below the level of the sea than the shafts or the basins of
which I have spoken, the limits to which man's labors have penetrated, or
than the depths to which the sea has in some few instances been sounded (Sir
James Ross was unable to find bottom with 27,600 feet of line), is as much
unknown to us as the interior of the other planets of our solar system. We
only know the mass of the whole Earth and its mean density by comparing it
with the open strata, which alone are accessible to us. In the interior of
the Earth, where all knowledge of its chemical and mineralogical character
fails, we are again limited to as pure conjecture, as in the remotest bodies
that revolve round the Sun. We can determine nothing with certainty
regarding the depth at which the geological strata must be supposed to be in
state of softening or of liquid fusion, of the cavities occupied by elastic
vapor, of the condition of fluids when heated under an enormous pressure, or
of the law of the increase
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of density from the upper surface to the center of the Earth.
The consideration of the increase of heat with the increase of depth toward
the interior of our planet, and of the reaction of the interior on the
external crust, leads us to the long series of volcanic phenomena. These
elastic forces are manifested in earthquakes, eruptions of gas, hot wells,
mud volcanoes and lava currents from craters of eruption and even in
producing alterations in the level of the sea.*
[footnote] * [See Daubeney 'On Volcanoes', 2d edit., 3848, p. 539, etc., on
the so called 'mud volcanoes', and the reasons advanced in favor of adopting
the term "salses" to designate these phenomena.] -- Tr.
Large plains and variously indented continents are raised or sunk, lands are
separated from seas, and the ocean itself, which is permeated by hot and
cold currents, coagulates at both poles, converting water into dense masses
of rock, which are either stratified and fixed, or broken up into floating
banks. The boundaries of sea and land, of fluids and solids, are thus
variously and frequently changed. Plains have undergone oscillatory
movements, being alternately elevated and depressed. After the elevation of
continents, mountain chains were raised upon long fissures, mostly parallel,
and in that case, probably cotemporaneous; and salt lakes and inland seas,
long inhabited by the same creatures, were forcibly separated, the fossil
remains of shells and zoophytes still giving evidence of their original
connection. Thus, in following phenomena in their mutual dependence, we are
led from the consideration of the forces acting in the interior of the Earth
to those which cause eruptions on its surface, and by the pressure of
elastic vapors give rise to burning streams of lava that flow from open
fissures.
The same powers that raised the chains of the Andes and the Hiimalaya to the
regions of perpetual snow, have occasioned new compositions and new textures
in the rocky masses, and have altered the strata which had been previously
deposited from fluids impregnated with organic substances. We here trace
the series of formations, divided and superposed according to their age, and
depending upon the changes of configuration of the surface, the dynamic
relations of upheaving forces, and the chemical action of vapors issuing
from the fissures.
The form and distribution of continents, that is to say, of that solid
portion of the Earth's surface which is suited to the luxurious development
of vegetable life, are associated by intimate connection and reciprocal
action with the encircling
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sea in which organic life is almost entirely limited to the animal world.
The liquid element is again covered by the atmosphere, an aÂrial ocean in
which the mountain chains and high plains of the dry land rise like shoals,
occasioning a variety of currents and changes of temperature, collecting
vapor from the region of clouds, and distributing life and motion by the
action of the streams of water which flow from their declivities.
While the geography of plants and animals depends on these intricate
relations of the distribution of sea and land, the configuration of the
surface, and the direction of isothermal lines (or zones of equal mean
annual heat), we find that the case is totally different when we consider
the human race -- the last and noblest subject in a physical description of
the globe. The characteristic differences in races, and their relative
numerical distribution over the Earth's surface, are conditions affected not
by natural relations alone, but at the same time and specially, by the
progress of civilization, and by moral and intellectual cultivation on which
depends the political superiority that distinguishes national progress.
Some few races, clinging, as it were, to the soil, are supplanted and ruined
by the dangerous vicinity of others more civilized than themselves, until
scarce a trace of their existence remains. Other races, again, not the
strongest in numbers, traverse the liquid element, and thus become the first
to acquire, although late, a geographical knowledge of at least the maritime
lands of the whole surface of our globe, from pole to pole.
I have thus, before we enter on the individual characters of that portion of
the delineation of nature which includes the sphere of telluric phenomena,
shown generally in what manner the consideration of the form of the Earth
and the incessant action of electro-magnetism and subterranean heat may
enable us to embrace in one view the relations of horizontal expansion and
elevation on the Earth's surface, the geognostic type of formations, the
domain of the ocean (of the liquid portions of the Earth), the atmosphere
with its meteorological processes, the geographical distribution of plants
and animals, and, finally, the physical gradations of the human race, which
is, exclusively and every where, susceptible of intellectual culture. This
unity of contemplation presupposes a connection of phenomena according to
their internal combination. A mere tabular arrangement of these facts would
not fulfill the object I have proposed to myself, and would not satisfy that
requirement for cosmical presentation awakened in me by the
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aspect of nature in my journeyings by sea and land, by the careful study of
forms and forces, and by a vivid impression of the unity of nature in the
midst of the most varied portions of the Earth. In the rapid advance of all
branches of physical science, much that is deficient in this attempt will,
perhaps, at no remote period, be corrected and rendered more perfect, for it
belongs to the history of the development of knowledge that portions which
have long stood isolated become gradually connected, and subject to higher
laws. I only indicate the empirical path in which I and many others of
similar pursuits with myself are advancing, full of expectation that, as
Plato tells us Socrates once desired, "Nature may be interpreted by reason
alone."*
[footnote] *Plato, 'Phaedo', p. 97. (Arist., 'Metaph.', p. 985.) compare
Hegel, 'Philosophie der Geschichte', 1840, s. 16.
The delineation of the principal characteristics of telluric phenomena must
begin with the form of our planet and its relations in space. Here too, we
may say that it is not only the mineralogical character of rocks, whether
they are crystalline, granular, or densely fossiliferous, but the
geometrical form of the Earth itself, which indicates the mode of its
origin, and is, in fact, its history. An elliptical spheroid of revolution
gives evidence of having once been a soft or fluid mass. Thus the Earth's
compression constitutes one of the most ancient geognostic events, as every
attentive reader of the book of nature can easily discern; and an analogous
fact is presented in the case of the Moon, the perpetual direction of whose
axes toward the Earth, that is to say, the increased accumulation of matter
on that half of the Moon which is turned toward us, determines the relations
of the periods of rotation and revolution, and is probably contemporaneous
with the earliest epoch in the formative history of this satellite. The
mathematical figure of the Earth is that which it would have were its
surface covered entirely by water in a state of rest; and it is this assumed
form to which all geodesical measurements of degrees refer. This
mathematical surface is different from that true physical surface which is
affected by all the accidents and inequalities of the solid parts.*
[footnote] *Bessel, 'Allgemeine Betrachtungen uber Gradmessungen nach
astronomisch-geodÂtischen Arbeiten', at the conclusion of Bessel and
Baeyer, 'Gradmessung in Ostpreussen', s. 427. Regarding the accumulation of
matter on the side of the Moon turned toward us (a subject noticed in an
earlier part of the text), see Laplace, 'Expos. du Syst. du Monde', p. 308.
The whole figure of the Earth is determined when we know the amount of the
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compression at the poles and the equatorial diameter; in order, however, to
obtain a perfect representation of its form it is necessary to have
measurements in two directions, perpendicular to one another.
Eleven measurements of degrees (or determinations of the curvature of the
Earth's surface in different parts), of which nine only belong to the
present century, have made us acquainted with the size of our globe, which
Pliny names "a point in the immeasurable universe."*
[footnote] *Plin., ii., 68. Seneca, 'Nat. Quaest., Praef., c. ii. "El
mundo espoco" (the Earth is small and narrow), writes Columbus from Jamaica
to Queen Isabella on the 7th of July, 1503: not because he entertained the
philosophic views of the aforesaid Romans, but because it appeared
advantageous to him to maintain that the journey from Spain was not long,
if, as he observes, "we seek the east from the west." Compare my 'Examen
Crit. de l'Hist. de la Geogr. du 15 me Siecle', t.i., p. 83, and t. ii., p.
327, where I have shown that the opinion maintained by Delisle, Freret, and
Gosselin, that the excessive differences in the statements regarding the
Earth's circumference, found in the writings of the Greeks, are only
apparent, and dependent on different values being attached to the stadia,
was put forward as early as 1495 by Jaime Ferrer, in a proposition regarding
the determination of the line of demarkation of the papal dominions.
If these measurements do not always accord in the curvatures of different
meridians under the same degree of latitude, this very circumstance speaks
in favor of the exactness of the instruments and the methods employed, and
of the accuracy and the fidelity to nature of these partial results. The
conclusion to be drawn from the increase of forces of attraction (in the
direction from the equator to the poles) with respect to the figure of a
planet is dependent on the distribution of density in its interior. Newton,
from theoretical principles, and perhaps likewise prompted by Cassini's
discovery, previously to 1666, of the compression of Jupiter,* determined,
in his immortal work, 'Philosophiae Naturalis Principia', that the
compression of the Earth, as a homogeneous mass, was 1/230th.
[footnote] *Brewster, 'Life of Sir Isaac Newton', 1831, p. 162. "The
discovery of the spheroidal form of Jupiter by Cassini had probably directed
the attention of Newton to the determination of its cause, and consequently,
to the investigation of the true figure of the Earth." Although Cassini did
not announce the amount of the compression of Jupiter (1/15th) till 1691
('Anciens Memoires de l'Acad. des Sciences', t. ii., p. 108), yet we know
from Lalande ('Astron.', 3me ed., t. iii., p. 335) that Moraldi possessed
some printed sheets of a Latin work, "On the Spots of the Planets,"
commenced by Cassini, from which it was obvious that he was aware of the
compression of Jupiter before the year 1666, and therefore at least
twenty-one years before the publication of Newton's 'Principia'.
Actual mesurements,
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made by the aid of new and more perfect analysis, have, however, shown that
the compression of the poles of the terrestrial spheroid, when the density
of the strata is regarded as increasing toward the center, is very nearly
1/300th.
Three methods have been employed to investigate the curvature of the Earth's
surface, viz., measurements of degrees, oscillations of the pendulum, and
observations of the inequalities in the Moon's orbit. The first is a direct
geometrical and astronomical method, while in the other two we determine
from accurately observed movements the amount of the forces which occasion
those movements, and from these forces we arrive at the cause from whence
they have originated, viz., the compression of our terrestrial spheroid. In
this part of my delineation of nature, contrary to my usual practice, I have
instanced methods because their accuracy affords a striking illustration of
the intimate connection existing among the forms and forces of natural
phenomena, and also because their application has given occasion to
improvements in the exactness of instruments (as those employed in the
measurements of space) in optical and chronological observations; to greater
perfection in the fundamental branches of astronomy and mechanics in respect
to lunar motion and to the resistance experienced by the oscillations of the
pendulum; and to the discovery of new and hitherto untrodden paths of
analysis. With the exception of the investigations of the parallax of
stars, which led to the discovery of aberration and nutation, the history of
science presents no problem in which the object attained -- the knowledge of
the compression and of the irregular form of our planet -- is so far
exceeded in importance by the incidental gain which has accrued, through a
long and weary course of investigation, in the general furtherance and
improvement of the mathematical and astronomical sciences. The comparison
of eleven measurements of degrees (in which are included three
extra-European, namely, the old Peruvian and two East Indian) gives,
according to the most strictly theoretical requirements allowed for by
Bessel,* a compression
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of 1/299th.
[footnote] *According to Bessel's examination of ten measurements of
degrees, in which the error discovered by Poissant in the calculation of the
French measurements is taken into consideration (Schumacher, 'Astron.
Nachr.', 1841, No. 438, s. 116), the semi-axis major of the elliptical
spheroid of revolution to which the irregular figure of the Earth most
closely approximates is 3,272,077.14 toises, or 20,924,774 feet; the
semi-axis minor, 3,261,159,83 toises, or 20,854,821 feet; and the amount of
compression or eccentricity 1/299.152d; the length of a mean degree of the
meridian, 57, |
