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COSMOS:
A SKETCH
OP
A PHYSICAL DESCRIPTION OF THE UNIVERSE.
BY
ALEXANDER VON HUMBOLDT.
TRANSLATED FROM THE GERMAN,
BY E. a OTTE.
MatarsB vero rerura vis atque majestas in omnibus momentis fide caret, si qiiia modo
partes ejus ac non totara complectatur animo. — Plin., Hist. Nat., lib. viL, c. 1.
IN TWO VOLUMES.
VOL. L
NEW YORK:
HARPER & BROTHERS, PUBLISHERS
329 & 331 PEARL STREET,
FRANKLIN SQUARE.
18 56.
TRANSLATOR'S PREFACE.
I CAN not more appropriately introduce the Cosmos than
by presenting a brief sketch of the life of its illustrious au-
thor.* While the name of Alexander von Humboldt is fa-
miliar 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 bom 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 pu-
pil 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
comitries, 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 oth-
er scientific pursuits, among which botany and the then re-
cent discovery of galvanism may be especially noticed. Bot-
any, 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 in-
struments which he afterward turned to so singularly excel-
lent an account.
The political disturbances of the civilized world at the close
* For the following remarks I am mainly indebted to the articles on
the Cosmos in the two leading Quarterly Reviews.
iv translator's preface.
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 posses-
sions 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 dia-
metrically 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 have in-
delibly 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 considera-
bly more than one hundred pounds sterling. Smce 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 govern-
ment. 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
translator's preface. v
the results obtained during their expedition are recorded by
our author in his Frag?nents Asiatiques, and in his Asie
Ce7itrale, 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 pubHc, 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 de-
voted 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 reaUty the
undefined vision that has so long floated before him. The
w;ork, when completed, wiU form three volumes. The first
volume comprises a sketch of all that is at present Imown of
the physical phenomena of the universe ; the second compre-
hends two distinct parts, the first of which treats of the in-
citements to the study of nature, afforded in descriptive poet-
ry, 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 him-
self 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 s;reat Picture of Na-
vi translator's preface.
ture." 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 philos
ophers of our own country, that, " should the conclusion cor-
respond (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 Alexan
der von Humboldt."
In venturing to appear before the English public as the in-
terpreter of " the great ivork of our age,^'^ I have been en-
couraged by the assistance of many kind literary and scientific
friends, and I gladly avail myself of this opportunity of ex-
pressing my deep obligations to Mr. Brooke, Dr. Day, Pro
fessor Edward Forbes, Mr. Hind, Mr. Glaisher, Dr. Percy, and
Mr. Ronalds, for the valuable aid they have afforded me.
It would be scarcely right to conclude these remarks with-
out a reference to the translations that have preceded mine.
The translation executed by Mrs. Sabine is singularly accu-
rate and elegant. The other translation is remarkable for
the opposite qualities, and may therefore be passed over in si-
lence. The present volumes differ from those of Mrs. Sabine
in having all the foreign measures converted into correspond-
ing 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 omit-
ting passages, sometimes amounting to pages, simply because
they might be deemed slightly obnoxious to our national prej-
udices.
* 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.
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 cotemporaries with a diffidence inspired
by a just mistrust of my own powers, while I would willingly
forget that writings long expected are usually received mth
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 de-
scriptive botany, geognosy, chemistry, astronomical determin-
ations 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 inter
course 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 illu-
sion. These special departments in the great domain of nat-
v'lii author's preface.
iiral science are, moreover, capable of being reciprocally fruc-
tified by means of the appropriative forces by which they are
endowed. Descriptive botany, no longer confined to the nar-
row 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 over the
earth's surface, according to distance from the equator and ver-
tical elevation above the sea. It is further necessary to in-
vestigate the laws which regulate the differences of tempera-
ture and climate, and the meteorological processes of the at-
mosphere, 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 dis-
tricts 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, m 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 geog-
raphy has thus, by an extended and perhaps too boldly imag-
ined 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
uo inconsiderable difficulties in the choice of the form utidev
AUTHOR S PREFACE. * IX
which such a work must be presented, if it would aspire to
the honor of being regarded as a Hterary composition. De-
scriptions 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 ob-
servation, 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 hestowed upon a small work bearing the title of Ansich-
ten der Natur, which I pubhshed 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, g;rassy plains, and deserts). The efiect produced
by this small volimie has doubtlessly been more powerfully
manifested in the influence it has exercised on the sensitive
minds of the young, whose imaginative faculties are so strong-
ly manifested, than by means of any thing which it could it-
self impart. In the work on the Cosmos on which I am now
engaged, I have endeavored to show, as in that entitled An-
sichten der Natur, that a certain degree of scientific com-
pleteness 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 sci-
ence, I undertook, for many months consecutively, first in the
French language, at Paris, and afterward in my own native
German, at Berhn (almost simultaneously at two different
places of assembly), to deUver a course of lectures on the phys-
ical 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,
author's preface.
of those portioiis of my discourses which have been preserved
by the industry of certain attentive auditors. V/ith the ex-
ception 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 pres-
ent condition of knowledge and opinions. Since the addi-
tions 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 con
tains 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 treatinjr a
physical description of the universe, and gives a general pic-
ture 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 vdth re-
gard to the connection existing between generalities and spe-
cialities, while it moreover exemplifies, by the form and style
of the composition, the mode of treatment pursued in the se-
lection 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 na-
ture (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 spe-
AUTHOR ^^ PREFACE-. XI
cial branches of the several departments of scienet, whose
mutual connection is indicated in the beginning of the work.
Wherever it has been possible to do so, I have adduced the au-
thorities from whence I derived my facts, with a view of afibrd-
ing 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, scat-
tered 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 inva-
riably preferred the repetition of the same words to any arbi-
ti'ary substitution of my own paraphrases. The much-con-
tested 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 occasion-
ally 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 dis-
coveries by which the age was characterized, I have been sim-
ply 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 dog-
matical modern opinions, and enter the free and fanciful do-
main of earlier presentiments.
It has frequently been regarded as a subject of discouraging
consideration, that while purely literary products of intellect
ual 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 phe-
nomena and physical laws, are subject to the most marked
modifications of form in the lapse of short periods of time, both
xii author's preface.
by the improvement in the instruments used, and by the con-
sequent expansion of the field of view opened to rational ob-
servation, and that those scientific works which have, to use
a common expression, become mitiquated by the acquisition
of new funds of knowledge, are thus continually being con-
signed 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 addi-
tions 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 re-
gards 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 ani-
mation and exalted grandeur, and to trace the stahle amid the
vacillating, ever-recurring alternation of physical metamorph-
oses, will not be wholly disregarded even at a future age.
PoUdam, Nov., 1844.
CONTENTS OF VOL. I.
Page
The Translator's Preface iii
The Author's Preface vii
Summary xv
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 Contempla-
tion 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 cele-
brated 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 Uni-
verse, acquired by the Inhabitants of a small Section of the tem-
perate 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 Observa-
tion 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, 61
Signification of the Word Cosmos .-. . 68—70
The Domain embraced by Cosmography 71
Empiricism and Experiments 74
The Process of Reason and Induction 77
XIV CONTENTS.
GENERAL REVIEW OF NATIJRAL PHENOMENA.
Connection betweei^ the Material and the Ideal World 80
Delineation of Nature 82
Celestial Phenomena 83
Sidereal Systems 89
Planetary Systems 90
Comets 99
Aerolites Ill
Zodiacal Light 137
Translatory Motion of the Solar System 145
The Milky Way 150
Starless Open'ngs 152
Terrestrial Phenomena 154
Geographical Distribution 161
Fio-ure 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
Geoo-nostic Phenomena 202
Earthquakes 204
Gaseous Emanations , 217
Hot Springs 221
Salses 224
Volcanoes 227
Rocks 247
PalfEontology 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
SUMMARY.
Translator's Preface.
Author's Preface.
«
Vol. I.
GENERAL SUMMARY OF THE CONTENTS.
Introduction. — Rejlections on the different Degrees of Enjoyment pre'
sented to us by the Aspect of Nature and the scientific Exposition of
the Laws of the Universe Page 23-78
Insight mto the connection of phenomena as the aim of all natural
investigation. Nature presents itself to meditative contemplation as a
jnity 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 effect produced by the individual character of a locality. Effect
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 firma-
ment and all the forms of vegetation — p. 23-33.
Tendency toward the investigation of the causes of physical phenom
ena. Erroneous views of the character of natural forces arising from
an imperfect mode of observation or of induction. The crude accu-
mulation of physical dogmas transmitted from one century to another.
Their diffusion among the higher classes. Scientific physics are asso-
ciated with another and a deep-rooted system of untried and misunder-
stood experimental positions. Investigation of natural laws. Appre-
hension 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 na
ture must necessarily be weakened by a study of its domain. Advant
ages of general views which impart an exalted and solemn character
to natural science. The possibility of separating generalities from
specialities. Examples drawn from astronomy, recent optical discov
eries, physical geognosy, and the geography of plants. Practicabil
ity of the study of physical cosmography — p. 33-54. Misunderstood
popular knowledge, confounding cosmography with a mere encyclope-
dic enumeration of natural sciences. Necessity for a simultaneous re-
gard 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 ; recip-
rocal connection existing between thought and speech — p. 54-5C
The notes to p. 28-33. Comparative hypsometrical data of the eleva-
tions of the Dhawalagiri, Jawahir, Chimborazo, iEtna (according to the
measureraeutof Sir John Herschel), the Swiss Alps, &c. — p. 28. Rarity
XVI SUMMARY OF THE CONTENTS.
of palms and ferns in the Himalaya Mountains — p. 29. European vz-
etable 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 cosmog
raphy. Separation of other kindred studies — p. 56-62. The urano-
logical portion of the Cosmos is more simple than the telluric ; the im-
possibility of ascertaining the diversity of matter simplifies the study
of the mechanism of the heavens. Origin of the word Cosmos, its sig-
nification of adornment and order of the universe. The existijig can
not be absolutely separated in our contemplation of nature from the
future. Histoiy of the world and description of the world — p. 62-73.
Attempts to embrace the multiplicity of the phenomena of the Cos-
mos in the unity of thought and under the form of a purely rational
combination. Natural philosophy, which preceded all exact observa-
tion in antiquity, is a natural, but not unfrequently ill-directed, eftbrt
of reason. Two forms of abstraction rule the whole mass of knowl-
edge, viz.: the quantitative, relative deteraiinations according to num-
ber and magnitude, and qualitative, material characters. Means of
submitting phenomena to calculation. Atoms, mechanical methods of
construction. Figurative representatiojus ; mythical conception of im-
ponderable matters, and the peculiar vital forces in every organism.
That which is attained by obsex-vation and experiment (calling forth
phenomena) leads, by analogy and induction, to a knowledge of empir-
ical laws; their gradual simplification and generalization. Arrange-
ment of the facts discovered in accordance with leading ideas. The
treasure of empirical contemplation, collected through ages, is in no dan-
ger 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 Koafiog 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 {to tt&v) in the celestial and terrestrial
spheres. Form and course of the representation. It begins with the
depths of space, of which we know little beyond the existence of
laws of gravitation, and with the region of the remotest nebulous spots
and double stars, and then, gradually descending through the starry
stratum to w^hich our solar system belongs, it contemplates this terres-
trial spheroid, surrounded by air and water, and, finally, proceeds to
the consideration of the form of our planet, its temperature and mag-
netic 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 vahces 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
eai'th, from which a merely subjective point of view might have led ua
to start, but rather with the objects comprised in the regions of space.
Distribution of matter, which is partially conglomerated into rotating
SUMMARY OF THE CONTENTS. XVil
nnd circling heavenly bodies of veiy 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 re-
ciprocal 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-mag-
netic 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. Mateiial pi'oducts which frequently accompany earthquakes. Gas-
eous 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 foi'ces 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. 247-284.
/. Geognostical epochs, which are indicated by the mineralogical dif-
ference of rocks, have determined the distnbution of solids and fluids
into continents and seas. Individual configuration of solids into hori-
zontal expansion and vertical elevation. Relations of area. Articula-
tion. Probability of the continued elevation of the earth's crust in
ridges— p. 284-301.
0-. Liquid and aenform envelopes of the solid surface of our planet.
Distribution of heat in both. The sea. The tides. CuiTents 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. Enu-
meration 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 geogi-aphy of vital
organisms; the geography of vegetables and animals. Physical grada-
tions of the human race — p. 339-359.
Special Analysis of the Delineation of Nature, including References to the
Subjects treated of in the Notes.
[. Celestial Portion of the Cosmos p. 83-154
The universe and all that it compnses — multiform nebulous spots,
planetary vapor, and nebulous stai-s. The pictui'esque 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 6 1
Cygui — p. 88 and note. Our solar system more complicated than was
conjectured at the close of the last century. Primary planets with Nep-
tune, Astrea, Hebe, Iris, and Flora, now constitute 16 ; secondary plan-
ets 18 ; myriads of comets of which many of the inner ones are inclosed
XVm SUMMARY OF THE CONTENTS.
in the orbits of the planets ; a rotating ring (the zodiacal light) and me-
teoric stones, probably to be regarded as small cosmical bodies. The
telescopic planets, Vesta, Junoj 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. Dif-
fei'ences of absolute magnitude, density, period of revolution, eccentric-
ity, 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 appi'oximation 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 di-
rections of the emanations in conoidal envelopes, with more or less
dense walls. Several tails inclined toward the sun ; change of form of
the tail; its conjectured rotation. Nature of light. Occultations of the
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 a6rolites (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 me-
teoric asteroids — p. 130 and notes. Ring of zodiacal light. Limita-
tion of the present solar atmosphere — p. 141 and note. Translatory
motion of the whole solar system — p. 145-149 and note. The exist-
ence 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 stra-
tum. Events in the universe ; the apparition of new stars. Propaga-
tion of light, the aspect of the stai'ry 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 meas-
urements 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. Three-
fold 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 stoiins ; extension of their action. Manifestations of magnet-
ic force on the earth's surface presented under three classes of phe-
nomena, namely, lines of equal force (isodynamic), equal inclination
(isoclinic), and equal deviation (isogenic). 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 observa-
SUMMARY OF THE CONTENTS. XIX
toi-ies 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 mere-
ly dynamic concussions or the upheaval of whole portions of the earth's
crust, accompanied by the eflfusion 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. Earth-
quakes. Extent of the circles of commotion and their gradual increase.
Whether there exists any connection between the changes in terres-
trial magnetism and the processes of the atmosphere. Noises, subter-
ranean thunder without any perceptible concussion. The rocks which
modify the propagation of the waves of concussion. Upheavals ; erup-
tion of water, hot steam, mud mofettes, smoke, and flame during au
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 eleva-
tion or among the detritus of their original structure. Permanent con-
nection 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. Height of the cone of cinders. Characteristics of those
volcanoes v^'hich 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 ele-
vated above the level of the sea (the study of the geographical form
and outlines of the different pai*ts of the earth). Classification of rocks
according to the scale of the phenomena of structure and metamorpho-
sis, which are still passing before our eyes. Rocks of eruption, sedi-
mentary rocks, changed (metamorphosed) rocks, conglomerates — com-
pound rocks are definite associations of oryctognostically simple fossils
There are four phases in the formative condition: rocks of eruption.
XX SUMIMARY OF THE CONTENTS.
endogenous (granite, sienite, porphyry, greenstone, hypersthene, rockj
eupliotide, melapbyre, basalt, and phonolithe); sedimentary rocks (si-
lurian schist, coal measures, limestone, travertino, infusorial deposit) ;
metamorphosed rock, which contains also, together with the detritus
of the rocks of eruption and sedimentary rocks, the remains of gneiss,
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 ra-
pidity of cooling. Origin of granular or saccharoidal marble, silicifica-
tion 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 doleritie
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 \atal 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 todtliegende and zechstein) ; the upper
ti'ias (bunter 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 ; tertiaiy 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 exist-
ing 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
bunter sandstone. Lignite and coal measures (amber-tree). Deposition
of large masses of rock ; doubts regarding their origin — p. 285 and note
/. The knowledge of geognostic epochs — of the upheaval of mount-
ain 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 configura-
tion of the earth's surface. Existing areal relations of the solid to the
fluid differ considerably from those presented by the maps of the phys-
ical 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 exten-
sion (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 form-
ation of the Atlantic Ocean. Forms which frequently recur — p. 285-
293 and notes. Ramifications and systems of mountain chains, and tho
means of determining their relative ages. Attempts to determine the
*enter of gravity of the volume of the lauds upheaved above the level
SUMMARY OF THE CONTENTS. XXI
of the sea. The elevation of continents is still progressing slowly, and
is being compensated for at some definite points by a perceptible sink-
ing. All geognostic phenomena indicate a periodical alternation 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
tlie other aeriform. Contrasts and analogies which these envelopes—
tlie sea and the atmosphere — present in their conditions of aggrega^
tion and electricity, and in their relations of currents and temperature.
Depths of the ocean and of the atmosphei-e, the shoals of which consti
tute our highlands and mountain chains. The degree of heat at the
surface of the sea in different latitudes and in the lower strata. Tend-
ency of the sea to maintain the temperature of the surface in the strata
nearest to the atmosphere, in consequence of the mobility of its j)arti-
cles 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 cur-
rent 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 algse, or on far-extending floating layers of fucus — p. 302-311
and notes.
k. The gaseous envelope of our planet, the atmosphere. Chemical
composition of the atmosphere, its transparency, its polarization, pres
sure, temperature, humidity, and electric tension. Relation of oxygen
to nitrogen ; amount of carbonic acid; carbureted hydrogen; ammo-
niacal vapors. Miasmata. Regular (horaiy) changes in the pressure
of the atmosphere. Mean barometrical height at the level of the sea
in different zones of the earth. Isobarometx'ical curves. Barometrical
windroses. Law of rotation of the winds, and its importance with ref-
erence to the knowledge of many meteorological processes. Land and
sea winds, trade winds and monsoons — p. 311-317. Climatic distribu-
tion 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 iso-
thermal lines in a horizontal and vertical direction, on the earth's sur-
face 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 the 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 tem-
perature. 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 atmos-
phere 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. Ditlerence
between the southern and northern hemispheres. Thennal scales of
XXll SUMMARY OF THE CONTENTS.
cultivated plants, going down from the vanilla, cacoa, and musacese, to
citrons and olives, and to vines yielding potable wines. The influence
which these scales exercise on the geographical distribution of culti-
vated plants. The favorable ripening and the immaturity of fruits are
essentially influenced by the difference in the action of direct or scat-
tered light in a clear sky or in one overcast with mist. General sum-
mary 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 temper-
ature, which correspond to one degree of geographical latitude. Equal-
ity of the mean temperature of a mountain station, and of the polar dis-
tance of any point lying at the level of the sea. Decrease of tempera-
ture 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; hab-
itability of the elevated plateaux of Thibet — p. 33 1 . Quantity of moist-
ure 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 disti-icts 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. Predetermina
tion 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 terres-
trial 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. Geog-
raphy of plants and animals. Migrations of organisms in the ovum, or
by means of organs capable of spontaneous motion. Spheres of distri-
bution depending on climatic relations. Regions of vegetation, and
classification of the genera of animals. Isolated and social living plants
and animals. The character of floras and faunas is not deteimined 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 nation-
ality, although certain historical occurrences have been the means of
diffusing idioms of the same family of languages among nations of wholb^
different descent — p. 351-359.
INTRODUCTION.
REFLECTIONS ON THE DIFFERENT DEGREES OF ENJOYMENT PRE-
SENTED TO US BY THE ASPECT OF NATURE AND THE STUDY OF HER
LAWS.
In attempting, after a long absence from my native coun-
try, 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 gener-
alities clothed in dry and dogmatical forms. Undue concise-
ness 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 deline-
ated 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 mere-
ly in its bearings on the material wants of life, but in its gen-
eral influence on the mtellectual advancement of rnankmd,
we find its noblest and most important result to be a knowl-
edge 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 intel-
lect, combined wdth the spirit of the age, in which are reflect-
ed 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 por-
tion 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 imag'i of
24 COSMOS.
a Cosmos, or harmoniously ordered whole, which, dimly shad-
owed forth to the human mind in the primitive ages of the
world, is now fully revealed to the maturer intellect of man
kind as the result of long and laborious observation.
Each of these epochs of the contemplation of the external
Vorld — the earliest dawn of thought and the advanced stage
of civilization — has its oWii source of enjoyment. In the
former, this enjoyment, in accordance with the simplicity of
the primitive ages, flowed from an intuitive feeling of the or
der that was proclaimed by the invariable and successive re-
appearance of the heavenly bodies, and by the progressive de-
velopment of organized beings ; while in the latter, this sense
of enjoyment springs from a definite knowledge of the phe-
nomena of nature. When man began to interrogate nature,
and, not conteijt with observing, learned to evoke phenomena
under definite conditions ; when once he sought to collect and
record facts, in order that the fruit of liis labors might aid in-
vestigation after his own brief existence had passed aw^ay, 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 w^eighs the value of ob-
servations, and substitutes induction and reasoning for con-
jecture 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 lanffuaofes exuberant in fisfurative exDressions ; and a few
of the best chosen symbols engendered by the happy inspira-
tion of the earliest ages, having by degrees lost their vague-
ness 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 dis-
similar in form and attributes ; one great whole {to -rrdv) an-
imated 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 mat-
ter, to determine with impartial justice what is due to the
discoveries of the past and to those of the present, and to an-
alyze the individual parts of natural phenomena without suo-
cumbing beneath the weight of the whole. Thus, and thus
alone, is it permitted to man, while mindful of the high des-
INTRODUCTION. 25
tiny 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 pre-
sented to us in the contemplation of nature, we find that the
ftrst place must be assigned to a sensation, which is wholly
mdependent 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 penetra-
ted 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 ev
ery 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 ex-
istence and the image of infinity revealed on every side, wheth-
er 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 enjoy-
ment, awakening impressions that are more vivid, better de-
fined, and more congenial to certain phases of the mind, than
those of which we have already spoken. At one time the
hiiart is stirred by a sense of the grandeur of the face of na-
ture, 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 contempla-
tion 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
Vol. I.— B
26 COSMOS.
various sensations that derive their charm and peimauencf
from the pecuhar character of the scene.
If I might be allowed to abandon myself to the recollections
»f my own distant travels, I would instance, among the most
•■■triking scenes of nature, the calm sublimity of a tropical night,
ivhen the stars, not sparkling, as in our northern skies, shed
cheir soft and planetary light over the gently-heaving ocean ;
)r I would recall the deep valleys of the Cordilleras, where
",he tall and slender palms pierce the leafy vail around them,
ind waving on high their feathery and arrow-like branches,
';brm, as it were, " a forest above a forest ;"* or I would de-
scribe the summit of the Peak of TenerifTe, when a horizontal
.ayer of clouds, dazzling in whiteness, has separated the cone
)f cinders from the plain below, and suddenly the ascending
iurrent 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 peace-
ful charm uniformly spread over the face of nature that moves
the heart, but rather the peculiar physiognomy and conforma-
tion of the land, the features of the landscape, the ever-vary-
ing 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
1 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 hap-
py illusion to believe that we receive from the external world
that with which we have ourselves invested it.
When far from our native country, after a long voyage, we
;read for the first time the soil of a tropical land, v/e expe-
•ience a certain feeling of surprise and gratification in recog-
lizing, in the rocks that surround us, the same inclined schis-
I ose strata, and the same columnar basalt covered with cellu-
iar amygdaloids, that we had left in Europe, and whose iden-
iity of character, in. latitudes so widely different, reminds us
!.hat the solidification of the earth's crust is altogether inde-
[leudent of climatic influences. But these rocky masses of
schist and of basalt are covered with vogetation of a character
with wluch we are unacquainted, and of a physiognomy wholly
* This expression is taken from a beautiful description of tropical
forest sceiieiy iu Paul and Virginia, by Bernardin de Saint Pierre.
INTRODUCTION. 27
unknown to us ; and it is then, amid the colossal and majestic
forms of an exotic flora, that we feel how wonderfully the flex-
ibility 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, thai
although the sight of a vegetation similar to that of our native
country might at first be most welcome to the eye, as the sweel
familiar sounds of our mother tongue are to the ear, we nev-
ertheless, by degrees, and almost imperceptibly, become famil
iarized with a new home and a new climate. As a true citi
zen of the world, man eveiy where habituates himself to tha'
which surrounds him ; yet fearful, as it were, of breaking tl ^
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 Avith in his native land ; and by
the mysterious relations existing among all types of organiza-
tion, the forms of exotic vegetation present themselves to his
mind as nobler and more perfect developments of those he had
loved in earher 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 land-
scape, and of every imposing scene in nature, depends so ma-
terially 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 emo-
tions 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 anal-
ysis of this nature present themselves to the eyes of the trav-
eler 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 con-
fines 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 sys-
teraatic views, are not only suited to please the imagination,
28 COSMOS.
but may also, when properly considered, indicate the grades
of the impressions of which I have spoken, from the miiform-
ity 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 Schreck-
horn,* or the Schneekoppe of Silesia on Mont Blanc, we should
* These comparisons are only approximative. The several eleva-
tions above the level of the sea are, in accurate numbers, as follows :
The Schneekoppe or Riesenkoppe, in Silesia, about 5270 feet, ac-
cording 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 Ti-igonometriques en Suisse, 1840, p. 230.) Mount
Athos, 6775 feet, according to Captain Gaultier; Mount Pilatus, 7546
feet; Mount ^Etna, 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 (calcu-
lated by assuming the terrestrial refraction to be 0'076) ; the Schreck
horn, 12,383 feet; the Jungfrau, 13,720 feet, according to TraUes ; Mont
Blanc, 15,775 feet, according to the diflferent measurements considered
by Roger {Bibl. Univ., May, 1828, p. 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.
The actual height of the Swiss mountains fluctuates, according to
Eschman's observations, as much as 25 English feet, owing to the vary-
ing thickness of the stratum of snow that covers the summits. Chim-
borazo 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 dilference of 445 feet between the determin-
ations of Blake and Webb, the elevation assigned to the Dhawalagiri
(or white mountain, from the Sanscrit dhawala, white, and giri, mount-
ain) can not be received with the same confidence as that of the Jawa-
hir, 25,749 feet, since the latter rests on a complete trigonometrical
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 (Hum-
boldt, 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
J(>- '•ney to the Boorendo Pass, 1840, vol. i., p. 143 and 311). Chimbo-
ru-^o 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 th« height of Chimborazo, which is only 21,421 feet,
and being nearly equal in elevation to the Jawahir, which is the highest
mouutaia in the Himalaya that has as yet been accurately measured.
INTRODUCTION. 29
not have attained to the height of that great Colossus of the
Andes, the Chimhorazo, whose height is twice that of Mount
^tna; and we must pile the Righi, or Mount Athos, on the
summit of the Chimhorazo, in order to form a just estimate
of the elevation of the Dhawalagiri, the highest point of the
Himalaya. But although the mountains of India greatly sur-
pass the Cordilleras of South America hy their astonishing el-
evation (which, after heing 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 does 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.* On the southern slope of the an-
cient Paropamisus, in the latitudes of 28^ and 34°, nature no
longer displays the same abundance of tree-ferns and arbores-
cent grasses, heliconias and orchideous plants, which in tropic-
Thus Mont Blanc is 5646 feet below Chimborazo ; Chimhorazo, 3770
feet below the Sorata ; the Sorata, 549 feet below the Jawahir, and prob
ably 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 meas-
urement 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 re-
ductions of the measux'ements.
[In the preceding note, taken from those appended to the Introduc-
tion in the French translation, rewritten by Humboldt himself, the
measurements are given in meters, but these have been convei'ted into
English feet, for the greater convenience of the general reader.] — Tr.
* 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 remark-
able series of lithographs of WalUch'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^° to 27^°) there has hitherto been observed only one
species of palm, Chamaerops martiana, Wall. {Plaidce 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 bmnoniaua, Wall, (of which a stem 48 feet long has been in
the possession of the British Museum since 1831), does not grow in Ne-
paul, but is found on the mountains of Silhet, to the northwest of Cal-
cutta, in lat. 24° 50'. The Nepaul fern, Paranema'cyathoides, Don,
formerly known as Sphaeroptera barbata, Wall. {Plantce 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, measm-ing 33 feet
in height; this is not, however, properly speaking, a tree.
30 CO&MOS.
al 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 cov-
ered with vegetable forms almost similar to those which char-
acterize Europe and Northern Asia. The species are not
identical, but closely analogous in aspect and physiognomy, as,
for instance, the juniper, the alpine birch, the gentian, the
marsh parnassia, and the prickly species of Ribes.* The
chain of the Himalaya is also wanting in the imposing phe-
nomena 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 inte-
rior of our planet.
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 be-
gins at an elevation of 11,000 or 12,000 feet above the level
of the sea,t thus setting a limit to the development of organic
** Ribes iiubicola, 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.), twenly-five oaks, four birches, two chestnuts, seven maples,
twelve willows, fourteen roses, three species of strawberry, seven spe-
cies 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° (see Carl von HUgel's Kasckmir, 1840, 2d pt.
249). Among the Coniferae, we find the Pinus deodwara, or deodara
(in Sanscrit, dewa-dar^i, 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. Moorcroftiaua, Swertia
purpurescens, S. speciosa, Parnassia armata, P. nubicola, Poeonia Emo-
di, Tulipa stellata; and, besides varieties of European genera peculiar
to these Indian mountains, true European species, as Leontodon tarax-
acum, Prunella vulgaris, Galium aparine, and Thlaspi arvense. The
heath mentioned by §aunders, in Turner's Travels, and which had been
confounded with Calluna vulgaris, is an Andromeda, a fact of the great-
est importance in the geography of Asiatic plants. If I have made use,
in this work, of the uuphilosophical expressions of Ejiropean genera,
European species, growing wild in Asia, &c., it has been in consequence
of the old botanical language, which, instead of the idea of a large dis-
semination, or, rather, of the coexistence of organic productions, has
dogmatically substituted the false hypothesis of a migration, which,
fi'om predilection*for Europe, is further assumed to have been from west
to east,
t On the southern declivity of the Himalaya, the limit of perpetual
Buow is 12,978 feet above the level of the sea; on the northern decliv-
ity, or, rather, on the peaks which rise above the Thibet, or Tartarian
INTKUIJUCIION. 3)
ahi in a zone that is nearly 3000 feet lower than that to which
it attains in the equinoctial region of the Cordilleras.
plateau, this limit is at 16,625 feet from 20^° to 32° of latitude, whilt
Bt the equator, iu the Andes of Quito, it is 15,790 feet. Such is the
resuh I have deduced from the combiuatiou of numerous data famished
by Webb, Gerard, Herbert, and Moorcroft. (See my two memoirs on
the mountains of India, in 1816 and 1820, iu the Ann. de CJdmie et di
Physique, t. iii., p- 303 ; t. xiv., p. 6, 22, 50.) The greater elevation to
which the Hmit of perpetual snow recedes on the Tartarian declivity
is owing to tlie radiation of heat from the neighboring elevated plains,
to tlie purity of the atmosphere, and to the infrequent formation of snow
in an air which is both very cold and veiy dry. (Humboldt, Asie Cen
trale, t. iii., p. 281-326.) My opinion on the ditference 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
iiue of perpetual snow is 13,000 feet. On the southern declivity, and
at latitude 31*^, Webb's measurements give me 13,500 feet, consequently
500 i'eet more than the height deduced from Captain Hodgson's oh
servations. Gerard's measurements fully confirm your opinion tha'
the hue of snow is higher on the northern than on the southern side.'
<t was not until the present year (1840) that we obtained the complett
and collected journal of the brothers Gerard, published under the su
pervision of Mr. Lloyd. {Narrative of a Journey from Caionpoor h
the Boorendo Pass, in the Himalaya, by Captain Alexander Gerard ant
John Gerard, edited by George Lloyd, vol. i., p. 291, 311, 320, 327, an<
^Ml.) Many interesting details regarding some localities may be fount ■
in tlie narrative of A Visit to the Shatool,for the Ptirpose of determinin.
the Line of Perpetual Stiow on the southern face of the Himalaya, in At
gust, 1822. Unfortunately, however, these travelers always confoun
the elevation at which sporadic snow falls with the maximum of th
height that the snow-line attains on the Thibetian plateau. Captaii
Gerard distinguishes between the summits that rise in the middle o
the plateau, where he states the elevation of the snow-line to be b(
*ween 18,000 and 19,000 feet, and the northern slopes of the chain o
»he Himalaya, which border on the defile of the Sutledge, and can ri
diate but little heat, owing to the deep ravines with which they ai ^
intersected. The elevation of the village of Tangno is given at onl »
9300 feet, while that of the plateau surrounding the sacred lake of Mj.
nasa is 17,000 feet. Captain Geraixl finds the snow^-line 500 feet lowt >.
on the northern slopes, where the chain of the Himalaya is broke i
through, than toward the southern declivities facing Hindostan, and h •
'.here estimates the line of perpetual snow at 15,000 feet. The moi
striking difierences are presented between the vegetation on the Thil
etian plateau and that characteristic of the southern slopes ot the Hin
alaya. On the latter the cultivation of grain is arrested at 9974 fee.
and even there the corn has often to be cut when the blades are sti.,
green. The extreme limit of forests of tali oaks and deodars is 11,900
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 ui
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 elevti
tioa of upward of 17,000 feet, that is to say, 1280 feet above the lowej
limits of the snow-line at the equator, in the province of Quito. It is-
H2 cosMv s.
But the countries bordering on the equator possess anoihei
advantage, to which sufficient attentign has not hitherto been
very desirable that the mean elevation of the Thibetiaii plateau, which
I have estimated at ouly 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 ihvestigated 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 Kemarks in his Geograph-
isclien Analyse der Karte von Inner Asien, 1841, s. 08.) 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,hov/ever,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
sufSce to establish the main fact, that the remarkable configuration of
the laud in Central Asia affords man all that is essential to the mainte-
nance 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 snov/-line at 15,667 feet, between 16° and 17|° south latitude. The
opinion that I had advanced regarding the difference in the snow-line
on the two faces of the Himalaya has heen most fully confirmed by the
barometrical observations of Victor Jacquemont, who fell an early sac-
I'ifice to his noble and unwearied ardor. (See his Correspondanc&
pendant son Voyage dans V Inde, 1828 a 1832, hv. 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 Kioubrong, 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.)
The same ti-aveler says, " To whatever height we rise on the south-
ern declivity of the Himalaya, the climate retains the same character,
and the same division of the seasons as in the plains of India ; the sum-
mer solstice being eveiy year marked by the same prevalence of rain,
w^hich continues to fall without intermission until the autumnal equi-
nox. 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 couise, 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
INTRODUCTION. 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 mount-
ains of Cundinamarca, of Quito, and of Peru, furrowed by
deep ravines, man is enabled to contemplate alike all the fam-
ilies 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 Musacese, 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 South-
ern 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 dis-
play 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 decliv-
ities of the Cordilleras.
Not to M'-eary 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 gen-
eral results whose combination constitutes the i^liy^ical delhie-
ation of the torrid zone. That which, m the vagueness of our
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 agita-
ted by storms, and in 34° 7' lat., snow^ is found, several feet in thick-
ness, from December to March.
* See, generally, my Essai sur la Geographie des Plantes, et le Ta-
bleau physique des Regions Equinoxiales, 1807, p. 80-88. On the diur-
nal and nocturnal variations of temperatui'e, see Plate 9 of my Atlas
Geogr. et Phys. du Nouveau Continent; and the Tables in my work,
entitled De distributione Geographica Plantarum, secundum cosli tempe-
riem, et altitudinem Montium, 1817, p. 90-116 ; the meteorological por-
tion of my Asie Centrale, t. iii., p. 212, 224; and, finally, the more
receut 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 Boussiugault's Memoir, Sur la profondeur a la-
quelle on trouve, sous les Tropiques, la coucke de Temperature Invaria-
ble. (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° and 35° F.
B2
34 COSMOS.
impressions, loses all distinctness of form, like some distant
mountain shrouded from view by a vail of mist, is clearly re-
vealed by the light of mind, which, by its scrutiny into the
causes of phenomena, learns to resolve and analyze their dif-
ferent 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 strong-
ly to the imagination, derives its collective interest from the
vivid truthfulness with which the individual features are por-
trayed.
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 vari-
ations of the atmosphere and the development of vital forces,
and by the contrasts of climate and vegetation exhibited at
different elevations, the invariability of the laws that regulate
the course of the heavenly bodies, reflected, as it were, in ter-
restrial 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 wliich 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 propor-
tion 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 con-
fines 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,
h^ve given place to monocotyledons, whose slender spikes con-
it"*,ute the sole covering of the soil. This is the zone of the
INTRODUCTION. 35
glasses, one vast savannah extending over the immense mount-
ain- plateaux, and reflecting a yellow, almost golden tinge, tc
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 or-
ganization, 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 sum-
mits of the Cordilleras ; and even where these subterranean
forces have opened a permanent communication with the at-
mosphere, through circular craters or long fissures, they rarelj
send forth currents of lava, but merely eject ignited scoriae,
steam, sulphureted hydrogen gas, and jets of. carbonic acid.
In the earhest stages of civilization, the grand and imposing
spectacle presented to the minds of the inhabitants of the trop-
ics could only awaken feelings of astonishment and awe. Il
might, perhaps, be supposed, as we have already said, that the
periodical return of the same phenomena, and the uniform man-
ner in which they arrange themselves in successive groups,
would have enabled man more readily to attain to a knowl-
edge 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 re-
searches have rendered it very doubtful whether the primitive
seat of Hindoo civihzation — one of the most remarkable phase.'
in the progress of mankind — was actually within the tropics
Airyana Vaedjo, the ancient cradle of the Zend, was situatec
to the northwest of the upper Indus, and after the great re
ligious schism, that is to say, after the separation of the Ir:i
uians from the Brahminical institution, the language that ha«
previously been common to them and to the Hindoos assume'
among the latter people (together with the hterature, habit:
and condition of society) an individual form in the Magodha oi
Madhya Desa,* a district that is bounded" by the great chaii.
* See, on the Madhjadecja, properly so called, Lassen's exceilei
work, entitled Indische Altcrthumskun'de, bd. i., s. 92. The Chinest
S6 cosivros.
oi' Himalaya and the smaller range of the Vindhya. In less
ancient times the Sanscrit language and civilization advanced
tovi^ard the southeast, penetrating further within the torrid zone,
as my brother Wilhelm von Humboldt has shov^^n in his great
work on the Kavi and other languages of analogous structure.*
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
that, in these climates, afiect the movements of the atmosphere
and the distribution of organic forms, it is to the inhabitants
of a small section of the temperate zone that the rest of man-
kind 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 civiliza-
tion 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 en-
joyment 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 im-
mortal poet has said, in our own tongue — Amid ceaseless
change seeks the unchanging pole.f
In order to trace to its primitive source the enjoyment de-
rived from the exercise of thought, it is sufficient to cast a
J:apid glance on the earliest dawnings of the philosophy of na-
ture, or of the ancient doctrine of the Cosmos. We find even
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.
* Ueber die Kawi Sprache aiif der Insel Java, nebst einer Einleiijinff
iiber die Verschiedenheit des menschlichen Spra^'hbaiies und ihren Ein
fluss auf die geistige Entwickelung des Mensckengeschlechf s, von Wil
helm V. Humboldt, 1836, bd. i., s. 5-510.
t This verse occurs in a poem of Schiller, entitled Der Spaziergayig
which first appeared in 1795, in the Horen.
INTRODUCTION. 37
among the most savage nations (as my own travels enable me
to attest) a certain vague, terror-stricken sense of the all-pow-
erful unity of natural forces, and of the existence of an invisi-
ble, 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 revela-
tion 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, de-
veloping in the mind of man, as a simple product of ideal con-
ception, and independently of the aid of observation, the first
germ of a Fhiloioiohy of Nature.
Among nations least advanced in civilization, the imagina-
tion revels in strange and fantastic creations, and, by its pre-
dilection for symbols, alike influences ideas and language. In-
stead of examining, men are led to conjecture, dogmatize, and
interpret supposed facts that have never been observed. The
inner world of thought and of feelins: does not reflect the imajje
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 en-
dowed with superior inteUigence, appears in other regions, and
among entire races of men, to be the result of mystic tenden-
cies 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 pre-
serving forces of the universe. But by degrees, as man, after
having passed through the different gradations of intellectual
development, arrives at the free enjo}rment 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, endeav-
ors 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. Inaccu
rate and imperfect observations have led, by false inductions,
to the great number of physical views that have been perpet-
uated as popular prejudices among all classes of society. Thus
by the side of a solid and scientific knowledge of natural phe-
nomena there has been preserved a system of the pretended
38 COSMOS.
results of observation, which is so much the more difficult to
shake, as it denies the vahdity of the facts by which it may
be refuted. This empiricism, the melancholy heritage trans-
mitted 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, distin-
guishes between that which is certain and that which is mere-
ly probable, and strives incessantly to perfect theory by ex-
tending 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 perpet-
uates 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 iiidependence offerees, 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
beheve that the order of nature is disturbed, it refuses to rec
ognize 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 Irom 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 maybe
comprehended in a single glance. Increased mental cultiva-
tion has given rise, in all classes of society, to an increased de-
sire of embellishing life by augmenting the mass of ideas, and
by multiplying means for their generalization ; and this sen-
timent fully refutes the vague accusations advanced against
the age in which we live, showing that other interests, be-
sides 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 alludo
to thejTear entertained by some persons, that nature rnay by
degrees lose a portion of the charm and magic of her power.
INTRODUCTION. 39
4S we learn more and more how to nnvail her secrets, com-
prehend 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
ehrouded in mystery and darkness, and does not admit of be-
mg classed among the conditions with which experience has
made us acquainted. The effect of such a power is, there-
fore, 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 tel
escopic comet in a group of nebulae, does not feel his imagina-
tion more excited — and this is the very guarantee of the pre-
cision of his labors — than the botanist who counts the divi-
sions of the calyx, or the number of stamens in a flower, or ex-
amines the connected or the separate teeth of the peristoma
surrounding the capsule of a moss. Yet the multiplied an-
gular 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.
We must not confound the disposition of mind in the ob-
server 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 spark-
ling 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
of organic forms. The vault of heaven, studded with nebu-
* Arago's ocular micrometer, a happy improvement upon Rochou'a
prismatic or double-refraction micrometer. See M. Mathieu's note ii
Delambre's Histoire de V Astronomic au dix-huUieme Siecle, 1827.
40 COSMOS
IsL' 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 w^orthy 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 sta-
tionary in the vault of heaven. Astronomy, by her aspiring la-
bors, has assigned indefinite bounds to space ; and if she have
set limits to the great nebula to which our solar system be-
longs, it has only been to show us in those remote regions of
space, which appear to expand in proportion to the increase
of our optic powers, islet on islet of scattered nebulce. The
feeling of the sublime, so far as it arises from a contemplation
of the distance of the stars, of their greatness and physical ex-
tent, 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 senti-
ment 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 de-
tails, 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 feel-
ings, and diminish the nobler enjoyments attendant upon a
contemplation of nature. Those who still cherish such erro
neous views in the present age, and amid the progress of pub-
lic opinion, and the advancement of all branches of knowledge,
fail in duly appreciating the value of every enlargement of th(;
sphere of intellect, and the importance of the detail of isolated
facts in leading us on to general results. The fear of sacri
ficing the free enjoyment of nature, under the influence of" sci-
entific 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
INTRODUCTION. 41
forces — ill 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 presenti-
ment 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 knowl-
edge. 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."
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 dis-
appeared in the great revolutions of our planet ; and as micro-
scopes 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 pro-
ductions, we see incessantly revealed the primordial mystery
of all organic development, that same great problem of meta-
Tnorpliosis which Gothe has treated with more than common
sagacity, and to the solution of which man is urged by his
desire of reducuiEr vital forms to the smallest number of fun-
damental types. As men contemplate the riches of nature,
and see the mass of observations incessantly increasing be-
fore them, they become impressed with the intimate convic-
tion 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 scien-
tific observer untrodden paths of discovery. The regret of
Alexander can not be appUed to the progress of observation
and intelligence.! 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 dif-
ferent branches of the study of natural history are only accessi-
ble in certain positions of social life, and do not, at every sea-
* Cams, Von den Urtheilen des Knochen und Schalen Gerustes, 18"2^
$ 6 + Plut., in Vita Alex. Magni, cap. 7
42 COSMOS.
son and m 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 w^ill fail to interest and
attract us, if they do not touch upon the subjects to v^^hich
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 pro-
gressive and retrograde movement of human society, so might
also the physical description of the world, the science of the
Co&inos, if it were grasped by a powerful intellect, and based
upon a knowledge of all the results of discovery up to a giv-
en period, succeed in dispelling a portion of the contradictions
which, at first sight, appear to arise from the complication oi
phenomena and the multitude of the perturbations simultane-
ously 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 mul-
tiple 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 habitu-
ally 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 compre-
hending the relations that exist between the most recent dis
coveries and those which have prepared the way for them.
Although fixed to one point of space, we eagerly grasp at a
knowledge of that wliich 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 ac-
quaintance with the results of distant voyages that we may
learn to comprehend some of the marvels of" terrestrial mag-
netism, and be thus led to appreciate the importance of the
estal lishments of the numerous observatories which in the
present day cover both hemispheres, and are designed to note
INTRODUCTION. 43
the simullaiieous occurrence of perturbations, and the frequen-
cy and duration of tnagnetic storms.
Let me be permitted here to touch upon a few points con-
nected with discoveries, whose importance can only be esti-
mated 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 preHminary knowledge
of the orbits of comets, we should be unable duly to appre-
ciate 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 com-
prehended 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 shglit disturbances in the
mean temperature of any given place, and thus afibrds suffi-
cient guarantee against the exaggerated apprehension of a
general and progressive deterioration of the climates of Eu-
rope. 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 un-
equal distribution determines the meteorological variations
of its atmosphere, depends alike upon the light-engendering
force of the sun ; that is to say, upon the conditio-i of its
gaseous coverings, and upon the relative position of the planet
and the central body.
44 COSMOS.
There are variations, it is true, which, in obedience to the
laws of universal gravitation, affect the form of the earth's or-
bit and the inclination of the ecliptic, that is, the angle M^hich
the axis of the earth makes with the plane of its orbit ; but
these periodical variations are so slow, and are restricted with-
in 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 4ay 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 dis-
tant 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 1 1th of August, of shoot-
ing stars, which probably form part of a belt of asteroids, in-
tersecting the earth's orbit, and moving with planetary ve-
locity.
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 ha.s
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 1 By means of this instrument we
are enabled to trace the striking analogy which exists be-
tween the formation of the granular rocks composing the
lava currents ejected from active volcanoes, and those endog-
enous misses of granite, porphyry, and serpentine, which, is-
suing from the interior of the earth, have broken, as erup-
tive rocks, through the secondary strata, and modified them
by contact, either in rendering them harder by the introduc-
tion 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 ,
INTKODUCTtON. 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, fur-
nished 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 tlio fact that the internal heat of the earth in-
creases so rapidly with the increase of depth that granite is
m 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 com-
position observed in thermal springs during a long course of
years. 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 dura-
tion 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 in-
* 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° F.
[Dr. Mantell states in The Wonders of Geology, 1848, vol. i., p. 34,
that this increase of temperature amounts to 1° of Fahrenheit for eveiy
fifty-four feet of vertical depth,"} — Tr.
46 coSxMos.
terior of the globe, at a period when the earth's crust we^
still furrowed and rent, and only in a state of semi-solidifica-
tion ; and a primordial condition is thus revealed to us, in
which the temperature of the atmosphere, and climates gen-
erally, were owing rather to a liberation of caloric and of dif-
ferent gaseous emanations (that is to say, rather to the ener-
getic reaction of the interior on the exterior) than to the posi-
tion of the earth with respect to the central body, the sun.
The cold regions of the earth contain, deposited in sedi-
mentary strata, the products of tropical climates ; thus, in
the coal formations, we find the trunks of palms standing up-
right amid coniferee, tree ferns, goniatites, and fishes having
rhomboidal osseous scales ;* in the Jura limestone, colossal
skeletons of crocodiles, plesiosauri, planulites, and stems of the
cycadese ; in the chalk formations, small polythalamia 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;t and, lastly, in transported soils, and in certain
caves, the bones of elephants, hyenas, and lions. 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
* See the classical woik on the fislies of the Old World by Agassiz,
Reck, 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 Palaeouiscus (called also Palueothrissum), lies buried beneath the
Jura formations in the old carboniferous strata. Scales which, in some
fishes, as in the family of Lepidoides (ordei* of Ganoides), are formed
like teeth, and covered in certain pai'ts with enamel, belong, after the
Placoides, to the oldest forms of fossil fishes ; their living representa-
tives are still found in two genera, the Bichir of the Nile and Senegal,
and the Lepidosteus of the Ohio.
\ [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 sili-
ceous shells of GaillonellcB, of such extreme minuteness that a cubic
inch of the stone contains forty-one thousand millions ! The Bergmehl
(mountain meal ov fossil farina) of San Flora, in Tuscany, is one mass
of auimalculites. See the interesting work of G. A Manlell, On Ik^f
Medals of Creation, vol. i., p. 223.]— jTr.
INTRODUCTJOX. 47
descriptive natural history, geology, or mathematical astron-
omy ? 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 aT5-
quainted with the specialities of phenomena, that he may ar-
rive 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 prepar-
ing on the physical laws of the universe, the greater part of
the facts advanced can be made manifest without the neces-
sity of appealing to fundamental views and principles. The
picture of nature thus drawn, notmthstanding 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 imagiuation.
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 efTect until the scaffolding is removed,
that had of necessity been used during its erection. 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 geo-
desical and astronomical operations by means of which these
pyramidal forms of continents have been determiued. In like
manner, physical geography teaches us by how many leagues
* Gotlie, iu Die Aphorismen ilbcr NaturwisscJischaft, bd. I., .s, 155
( Werke kleine Ausgabe, von 1833.)
48 COSMOS.
the equatorial axis exceeds the polar axis of the globe, and
shows us the mean equality of the flattening of the two hemi-
spheres, without entaiUng 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 regu-
lar ellipsoid of revolution, and that this irregularity is reflect-
ed 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 Verhciltniss
zur Natur und zur Geschichte, in which Carl Emitter so ably
delineates the physiognomy of our globe, and shows the influ-
ence 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' Exjoosition du Sijs-
te?7ie dtc Monde, in which the author has combined the results
of the highest astronomical and mathematical labors, and pre-
sented them to his readers free from all processes of demon-
stration. 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 sepa-
ration of the general from the special, are not only conducive
to the attainment of perspicuity in the composition of a phys-
i'-al 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 ena-
bled 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
•he close of the last century, in the condition of all the special
sciences, more particularly of geology, chemistry, and descrip-
t.ive natural history. In proportion as laws admit of more
.general application, and as sciences mutually enrich each other,
md by their extension become connected together in more im-
oierous and more intimate relations, the development of gen-
eral truths may be given with conciseness devoid of superfici-
ality. On being first examined, all phenomena appear to be
INTRODUCTION. 49
isolated, and it is only by the result of a multiplicity of obser-
vations, 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 w-ant of connec-
tion 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 dis-
covery, 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 phydcal geography,
combined icith a descrijotion of the regions of space and the
bodies occujnjing them. Devoid of the profoundness of a purely
speculative philosophy, my essay on the Cos^nos treats of the
contemplation of the universe, and is based upon a rational
empiricism, that is to say, upon the results of the facts regis-
tered 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 individuahties, and the essen-
tial variations of the actual, whether in the form and arrange-
ment of natural objects in the struggle of man against the
elements, or of nations against nations, do not admit of being
Vol. I— C
50 COSMOS.
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 govel'n the moral
world, exercise their action under the control of primordial
necessity, and in accordance with movements occurring period-
ically 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, obe-
dient 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 descrip-
tion of the universe, and appertains to a range of higher spec-
ulative views.
Emanuel Kant, one of the few philosophers who have es-
caped the imputation of impiety, has defined with rare sagac-
ity the limits of physical explanations, in his celebrated essay
On the Theory and Strncture of the Heaven?,, 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 w^e 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 re-
sisted the attempts made to explain them within the narrow
limits of our own sphere of observation. Organic forms tliat
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 endov/
INTRODUCTION. 51
ed 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 oppo-
site liemisphere. These are, so to speak, the equivalents w^hich
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 de-
velopment of certain parts, in the mode of junction of distinct
organs, in the differences in the balance of forces, or in a re-
semblance to intermediate forms which are not permanent,
but merely characteristic of certain phases of normal devel-
opment. 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 sediment-
ary strata they have uplifted, and by the directions which
they follow over the long fissures with which the earth's crust
is furrowed. Relations of superposition of trachyte and of
syenitic porphyry, of diorite and of serpentine, which remuin
doubtful when considered in the auriferous soil of Hungary,
in the rich platinum districts of the Oural, and on the south-
western declivity of the Siberian Altai, 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 accu-
mulated by chance. It has at length been fully acknowledg-
ed, 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 condi-
tion of the science he would enlarge, and is guided by reason
in his researches.
It is by this tendency to generalization, which is only dan-
gerous in its abuse, that a great portion of the physical knowl-
edge already acquired may be made the common property of
all classes of society ; but, in order to render the instruction
imparted 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 t^e inappropriate term of popula?
52 cosjMos.
knowledge. I take pleasure in persuading myself that scien-
tific subjects may be treated of in language at once dignified,
grave, and animated, and that those who are restricted with-
in the circumscribed limits of ordinary life, and have long re-
mained 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 acquisi-
tion of new ideas. Communion with nature awakens within
us perceptive faculties that bad long lain dormant ; and we
thus comprehend at a single glance the influence exercised by
physical discoveries on the enlargement of the sphere of intel-
lect, and perceive how a judicious application of mechanics,
chemistry, and other sciences may be made conducive to na-
tional 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 mat-
ter 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 the-
oretical," 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 cotemporaries could never have anticipated that
the action of the voltaic pile would discover to us, in the al-
kalies, metals of a silvery luster, so light as to swim on wa-
ter, 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 Huygens first ob-
served, 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 ijolarization, 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, oi
INTRODUCTION. 53
whether comets transmit light directly or merely by reflec-
tion.*
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 en-
lightened 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 na-
tional prosperity, must be the award of those states who shrink
with slothful indifierence from the great struggle of rival na-
tions in the career of the industrial arts. It is with nations
as with nature, which, according to a happy expression of
G6the,t " knows no pause in progress and development, and
attaches her curse on all inaction." 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 ac-
quaintance 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 in-
destructible 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 spariiigly 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 di-
minish in proportion as neighboring countries become strength-
ened 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 inwaid one — an ennoblement of the intellect — so ought
we likevidse, in our pursuit of science, to strive after a knowl-
edge of the laws and the principles of unity that pervade the
vital forces of the universe ; and it is by such a course that
* Ai'ago's Discoveries ia the year 1811. — Delambre's Histoire de
V Ait., p. 652. (Passage already quoted.)
t Gothe, ill Die AphoHsmen uber Naturwissenschaft. — Werke, bd. 1...
B. 4
54 COSMOS.
physical studies may be made subservient to the progress of in-
dustry, which is a conquest of mind over matter. By a hap-
py connection of causes and effects, we often see the useful link-
ed to the beautiful and the exalted. The improvement of agri-
culture in the hands of freemen, and on properties of a mod-
erate 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
contact of nations v^^ith each other, are all brilliant results 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 char-
acteristic of the present age, should necessarily have a tenden-
cy 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 devel-
oped beneath the ff^gis 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 nourish-
ment 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 Spar-
tans, notwithstanding their Doric austerity, prayed the gods
to grant them " the beautiful with the good."*
I will no longer dwell upon the considerations of the influ-
ence 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. Ac-
customed 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 mount-
ains : they praise the view even when great part of the dis-
tant plains lie hidden by clouds, knowing that this half-trans-
parent vapory vail imparts to the scene a certain charm from
* Pseudo-Plato. — Alcib., xi., p. 184, ed. Steph. ; Plut., Instituta La-
conica, p. 253, ed. Hutten.
, j\TKoDi;( rrox. oa
the power exercised by the imagination over the domani of the
senses. In like manner, from the height occupied by the phys-
ical history of the world, all parts of the horizon will not ap-
pear 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 unskill-
fulness 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 phys-
ical 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 conmion focus, and thus arrive at a point of view from
w^hich all the organisms and forces of nature may be seen as
one Hving, active whole, animated by one sole impulse, " Na-
ture," 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 uni-
verse — 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 con-
vert 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 re-
garded as a. mere encyclopedic aggregation of the most im-
portant and general results that have been collected together
from special branches of knowledge. These results are noth-
ing more than the materials for a vast edifice, and their com-
bination can not constitute the physical history of the w^orld,
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
vao-ue as their limits are ill defined. In the work before us,
partial facts will be considered only in relation to the whole
5(j COSMOS.
The higher the point of view, the greater is the nece*,sity lor
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 langiiage, by its originality of structure and its
native richness, can, in its delineations, interpret thought M^ith
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 man-
ifested 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 advant-
ages he has enjoyed in being permitted to express his thoughts
in his native language ; and truly happy is he who, in at-
tempting 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 efiii-
sions of creative fancy, has for centuries past exercised so pow-
erful an influence over the destinies of man.
M.MITS 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 enjoy-
ments presented by the aspect of nature, varying as they do
in the sources from whence they flow, may be multiplied and
ennobled by an acquaintance with the connection of phenom-
ena 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 descriiJtion of the utiiverse should
be conducted, and to indicate the limits of this science in ac-
cordance 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 phenom-
INTRODUCTION. 57
ena which are found to be distributed in various g^roups, I would
consider a few general questions intimately connected together,
and bearing upon the nature of our kno^vledge 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 uni-
verse, considered as a distinct science.
2. A brief enumeration of the totality of natural phenomena,
presented under the form of a general delineatioii 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 anima-
tion 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 pro-
gressive 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 phenome-
na 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 pre-
sents itself, therefore, to man, as the inhabitant of the earth,
under a two-fold form — as the earth itself and the reo-ions of
space. It is with a view of showing the actual character and
the independence of the study of physical cosmography, and at
the saraie time indicating the nature of its relations to general
fhysics, descrij)tive 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
C2
58 COSMOS.
of empirical knowledge by terms which admit either ot too
wide or too limited a definition of the ideas which they were
intended to convey, and arc, besides, objectionable from hav-
ing had a different signification in those classical languages of
antiquity from which they 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 vague-
ness, are now generally understood. These changes have been
proposed, for the most part, by those who have occupied them-
selves with the general classification of the various branches
of knowledge, from the first appearance of the great encyclo-
pedia [Margarita Pliilosophica) 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. t
* The Margarita PhilosopJiica of Gregory Reisch, prior of the Char-
treuse at Freiburg, first appeared under the following title : Epitome
omnis Philosophice, alias Margarita PhilosopJiica, tractans de omni generi
scibili. The Heidelberg edition (1486), and that of Strasburg (1504),
both bear this title, but the first part was suppi'essed in the Freiburg
edition of the same year, as well as in the twelve subsequent editions,
vvhich succeeded one another, at short intervals, till 1.535. This work
exercised a great influence on the ditfusion of mathematical and physic-
al sciences toward the beginning of the sixteenth century, and CLas^es,
the learned author of L'Apercu Historique des Methodes en GeomHrtc
(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 PhilosopTiica, 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
VValdseemiiller), 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 G^o-
grapkip. du Nouveau Continent, et des Progres de V Astronomie Nautiqtie
aux 15e et 16e Siecles, t. iv., p. 99-125.
t Ampere, Essai sn.r la Phil, des Sciences, 1834, p. 25. Whewell,
IXTHODITTroW 59
The selection of an inappropriate Greek nomenclature has per-
haps 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 uni-
verse as an object of the external senses, does undoubtedly re-
quire the aid of general physics and of descriptive natural histo-
ly, but the contemplation of all created thmgs, which are hnked
together, and form one luhole, animated by internal forces, gives
to the science we are considering a peculiar character. Phys-
ical 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 consid-
ered as depending upon the primitive and vital action of one
sole force, from which emanate all the movements of the uni-
verse. The terrestrial portion of physical cosmography, for
which I would willingly retain the expressive designation of
'physical geograjjhij, 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 re-
pulsion 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, hav-
ing been elevated at different epochs, constitute distinct sys-
tems, whether they run in parallel lines or intersect one an-
other ; 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 prox-
imity with the sea-shore. It depicts the eruptive rocks as
principles of movement, acting upon the sedimentary rocks by
traversing, uplifting, and inchning them at various angles ; it
Philosophy of the Inductive Sciences, volt ii., p. 277. Park, Pantoiogy^
* All changes in the physical world may be reduced to motion.
Aristot., Phys. Ansc, 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. Psendo-Aris-
tot., De Mundo. cap. vi., p. 398.
.«|HX^
60 COSMOS.
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 ot
the science of the Cosmos describes the strife of the liquid ele-
ment 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 consider-
able distance, Avhere the elevation of the strata of the mount-
ain 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 falling rather within the domain
of geography, properly so called. We would here only con-
sider phenomena in their mutual connection, and in their re-
lations to different zones of our planet, and to its physical con-
stitution generally. The specialities both of inorganic and or-
ganized matter, classed according to analogy of form and com-
position, undoubtedly constitute a most interesting branch of
study, but they appertain to a sphere of ideas having no affin-
ity 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 differenl
descriptions, ranged in series, would as little give us a tru«
image of the general conformation of the irregular surface of
our globe, as a succession of all the floras of different region?
would constitute that M^iich I designate as a Geogra2)hy 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 be
tween the climatic distribution of beings and the individualitj
of organic forms (in the morphology or descriptive natural his-
tory of plants and animals) ; and it is by induction that we
are led to comprehend numerical laws, the proportion of nat-
ural families to the whole number of species, and to desig-nate
the latitude or geographical position of the zones in whose
INTRODUCTION. 61
plains each org:anic form attains the maximum of its develop-
ment. Considerations of this nature, by their tendency to
generalization, impress a nobler character on the physical de-
scription of the globe, and enable us to undfrstand 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 for-
merly 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 articula-
tions. But these pretended systems of nature, however ingen-
ious their mode of classification may be, do not show us or-
ganic beings as they are distributed in groups throughout our
planet, according to their difierent 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 recognize unity in the vast diversity of
phenomena, and by the exercise of thought and the combina-
tion 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 neces-
sary to descend to veiy special facts ; but this will only be in
order to recall the connection existing betM^een the actual dis-
tribution of organic beings over the globe, and the laws of the
ideal classification by natural families, analogy of internal or-
ganization, 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 phys
ical history of the globe, the innumerable multitude of organ-
ized bodies which embellish creation are considered rather ac-
cording to zones of habitation or stations, and to differently
inflected isothermal bands, than with reference to the princi-
ples of gradation in the development of internal organism.
Notwithstanding this, botany and zoology, which constitute
62 COSMOS.
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 — Graminese and
Orchideee, Coniferse 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 disper-
sion is, however, only apparent. The physical description of
the globe teaches us that vegetation every where presents nu-
merically 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 laiv of substi-
tution, which seems to depend upon some inherent mysteries
of the organism, considered with reference to its origin, main-
tains 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
find a principle of unity and a primitive plan of distribution
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 or-
ganic 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, ac-
cording 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 attrac-
tions that are not determined solely by the relations of mass,
we must admit that the description of the earth comprises at
INTRODUCTION. (53
once physical and chejiiical actions. In addition to gravita-
tion, 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 ajjinity, 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. 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 depend-
ing upon the quantitative relations of matter or the distribu-
tion 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 heteroofeneous 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
luminous waves, and by the influence universally exercised by
the force of gravitation or the attraction of masses. The ex-
istence of a periodical action of the sun and moon on the va-
riations of terrestrial magnetism is even at the present day
extremely problematical. We have no direct experimental
knowdedge regarding the properties and specific qualities of
the masses circulating in space, or of the matter of w^hich they
are probably composed, if we except what may be derived from
the fall of aerolites or meteoric stones, wdiich, as we have al-
ready 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
* On the question already discussed by Newton, regarding the differ-
ence existing between the atti-action 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. AnfangR.
grunde der Naturwissenschaft, Sam. Werke, 1839, bd. v., s. 309 (Meta-
physical Principles of the Natural Sciences) ; Pectet, Physique, 1838-
vol, i., p. 59-63.
64 COSMOS.
they are small celestial bodies, which, being attracted by out
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 com-
posing 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 sphe-
roids, being integrant parts of the same system, and having
one common origin, may likewise be composed of substances
chemically identical. Again, experiments with the pendulum,
particularly those prosecuted with such rare precision by Bes-
sel, confirm the Newtonian axiom, that bodies the most hete-
rogeneous in their nature (as water, gold, quartz, granular
limestone, and diflerent masses of aerolites) experience a per-
fectly 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 satel-
lites, on Encke's comet of short period, and on the small planets
Vesta, Juno, Ceres, and Pallas, indicates with equal certain-
ty that within the limits of actual observation attraction is
determined solely by the quantity of matter. t
This absence of any perceptible difierence in the nature of
matter, alike proved by direct observation and theoretical de-
ductions, 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 terres-
trial portion on physics, chemistry, and organic morphology ;
but the domain of these three last-named sciences embraces
* [The analysis of an aeroHte which fell a few years since in Mary
land. United States, and was examined by Professor Silliman, of New
Haven, Connecticut, gave the following results: Oxyd of iron, 24 ; ox-
yd 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.]— 7V.
t Poisson, Connaissances des Temps pour V Annee 1836, p. (j4-6().
Bessel, Poggeudorf 's Annalen, bd. xxv., s. 417. Encke, Abhandhingen
der Berliner Academie (Trans, of the Berlin Academy), 1826, s. 257.
Mitscherlich, Lehrbuck der Chemie (Manual of Chemistry), 1837 bd. i.
8. 352.
INTRODUCTION. 65
the consideration of phenomena which are so complicated,
and have, up to the present time, been found so little suscep-
tible of the application of rigorous method, that tht) physical
science of the earth can not boast of the same certainty and
simplicity in the exposition of facts and their mutual connec-
tion 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 Philolaiis, and subse-
quently 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 meas-
ure, to the form of bodies, and to the number and distances of
the planets,*" while the Ionian physicists directed their atten
tion to the qualities of matter, its true or supposed metamor
phoses, and to relations of origin. 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 oiaturaL 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 pio-
neer cf •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,
* Compare Otfried MUller's Dorien, bd. i., s. 365.
■U6 ^ COSMOS.
and with a geographical sketch of the universe, or, I would
rather say, a true map of the ivorld, such as was traced by
the bold hand of the elder Herschel. If, notwithstanding the
sraallness 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 subordina-
tion of the celestial to the terrestrial portion is met with in the
great work of Bernard Varenius,'* w^hich appeared in the mid-
* Geographia Generalis iii qua affectiones generales telluris expli-
cantur. The oldest Elzevir edition bears date 1650, the second 1672,
and the third 1681 ; these were published at Cambridge, under New-
ton's supervision. This excellent work by Varenius is, in the true
sense of the words, a physical description of the earth. Since the work
Hlstoria 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 rich-
er 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 w^ell-informed travelers. Generalis sive Universalis Geo-
graphia dicitJir qute tellurem in genere considerat atque affectiones ex'
plicat, non^ habita particulariitm regionum ratione. The general de-
scription of the earth by Varenius {Pars Ahsoluta, cap. i.-xxii.) maybe
considered as a treatise of comparative geography, if we adopt the term
used by the author h.\m?,e\i {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 con-
tinents (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 I'elatively to the height of neighboring coasts (p. 103) ;
the uniformity of level observed in all open seas (p. 97) ; the depend-
ence 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 ditferences of temperature, &c. 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. Augustiu, 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, be-
tween 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 spirihium inclusorum vi,
sicut aliquando monies e terra protttsos esse quidam scribunt (p. 225).
The edition published by Newton in 1681 {auciior et emendatior) un^
fortunately contains no additions from this great authority; and there
is not even mention made of the polar compression of the globe, al-
IXTIIODUCTIOX. 07
d\e of the seventeenth century. He was tlie first to distinguish
between general a?id special geography, the former of which
he subdivides into an absolute, or, properly speaking, terres-
trial part, and a relative or planetary portion, according to
the mode of considering our planet either with reference to its
surface in its diliereiit 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 imper-
fect state of many of the auxiliary sciences from which this
. writer was obliged to draw his materials prevented his work
from corresponduig 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.*
The enumeration of the most important results of the as-
tronomical 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 ad-
venturous than the title. The introduction of new terms, es-
pecially with reference to the general results of a science which
- though the experiments on the pendulum by Richer had been made
nine years prior to the appearance of the Cambridge edition. Newton's
Principia Mathematica Philosojjhice Natnralis were not communicated
in manuscript to tlie Royal Society until April, 1G80. Much uncer-
tainty seems to prevail regarding the birth-place of Varenius. Ja;cher
says it was England, while, according to La Biographie Universclle
(b. xlvii., p. 495), he is stated to have been bom at Amsterdam; but
it would appear, from the dedicatory address to the burgomaster ol
that city (see his Geographia Comparativa), that both suppositions ai'e
false. Varenius expressly says that lie 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 Ger-
many, and to the devastations of the Thirty Years' War. In his dedica-
tion of another work, Descriptio regni Japonic^ (Amst., 1649), to the
Senate of Hamburgh, Varenius says that he prosecuted his elementary
mathematical studies in the gymnasium of that city. There is, there-
fore, every reason to believe that this admirable geographer was a
native of Germany, and was probajjly born at Luneburg ( TFV/^e?i. Mem.
Theol., 1685, p. 2142; Zedler, Universal Lexicon, vol. xlvi., 1745. p.
187).
* Carl Ritter's Erdkundeim VerhuUniss zur Naturund zvr Geschichte
des Menschen, oder allgemeine vergleichende Geographic (Geojjraphy in
relation to Nature and the History o' Man, or general Comparativo
Geography).
68 COSMOS.
ought to be accessible to all, has always been greatly in oppo-
sition 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 in-
troduction of hitherto unknown objects rendered new names
necessary. The denominations of physical descriptions of the
universe, or physical cosmography, which I use indiscrimin-
ately, have been modeled upon those o{ physical descriptio?is
of the earth, that is to say, physical geography, terms that
have lonor heen in common use. Descartes, whose o^enius 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 him-
self 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 wddely-extended horizon — of the
assemblage of all things with which space is filled, from the
remotest nebula? to the climatic distribution of those delicate
tissues of vegetable matter which spread a variegated cover-
ins: over the surface of our rocks.
The influence of narrow-minded views peculiar to the ear-
lier ages of civilization led in all languages to a confusion of
ideas in the synonymic use of the words earth and tvorld,
while the common expressions voyages round the ivorld, map
of the ivorld, and neiu ivorld, afford further illustrations of the
same confusion. The more noble and precisely-defined ex-
pressions of system of the ivorld, the planetary ivorld, and
creation and age of the ivorld, 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 uni-
form and regular movements of the sun and planets. Thus
the word Cosmos, which primitively, in the Homeric ages, in-
dicated an idea of order and harmony, was subsequently adopt-
ed 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 Philolaiis, whose fragmentary works have been so ably com-
mented upon by Bockh, and conformably to the general testi-
INTRODUCTION. 69
mony of antiquity, Pythagoras was the first who used the
word Cosmos to designate the order that reigns in the uni-
verse, or entire world.*
* Koofioc, 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 evra^ia, it implied, the or-
der 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 writ-
ings ; but ancient attestation to the truth of this assertion is to be found
in several passages of the fragmentary works of Philolatis (Stob., Eclog.,
p. 360 and 460, Heeren), p. 62, 90, in Bockh's German edition. I do
not, according to the example of Niike, cite Tim.'eus of Locris, since hia
authenticity is doubtful. Plutarch {De plac. Phil., ii., 1) says, in the
most express manner, that Pythagoras gave the name of Cosmos to the
universe on account of the order which reigned throughout it; so like-
wise does Galen {Hist. Phil., p. 429). This word, together with its
novel signification, passed from the schools of philosophy into the lan-
guage ot poets and prose writers. Plato designates the heavenly bod-
ies by the name of Uranos, but the order pervading the regions of space
he too terms the Cosmos, and in his Timmus (p. 30, b.) he says that the
world is an animal endowed tcith a soul {KOCfiov ^cjou kiiypv^ov). Com-
pare Anaxag. Claz., ed. Schaubach, p. Ill, and Plut. {De plac. Phil.,
ii., 3), on spirit apart from matter, as the ordaining power of nature.
In Aristotle {De Casio, 1, 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., 2, 1, and I., 3, 13, p. 339, a, and 340, b, Bekk.) The def-
inition of Cosmos, which I have already cited, is taken from Pseudo-Ar-
istoteles de Mundo, cap. ii. (p. 391); tte passage referred to is as fol-
lows: Koa^og earl nvoTijua kg ovpavov koL yfjg Kul tuv ev Tovrotg Trepte-
XOfiivuif (pvaeov. AeyeTac de Kal eKepcog K6a2,og rj ribv bT^uv rd^ig re kuI
6iaK6(yfj,r]aig, vno t^euv re Kai did d^aijv (pv/iaTTOfiivri. Most of the pas-
sages 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
iipon the Epistles of Phalaris, 1817, p. 254) ; on the histoiical existence
of Zaleucus, legislator of Leucris, in Nake's excellent work, Sched.
Crit., 1812, p. 9, 15; and, finally, in Thcophilus 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, Gesck. der Griechisck-Romischen Philosophie, h. i., s. 252 (His-
tory of the Greco-Roman Philosophy). Each of these groups forming
thus a Cosmos, the universe, to ttuv, the word must be understood in a
wider sense (Pint., 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 inscnptions in praise of Trajan and Adrian ( Corpus Inscr. Grcec.,
1, n. 334 and 1036), in which Koafiog occurs for oLKOVjiivrj, 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
70 COSMOS.
From the Italian school of philosophy, the expression pass-
ed, in this signification, into the language of those early poets
into three parts, the Olympus, Cosmos, and Oui\tnos (Stob., i., p. 488;
Philolatis, p. 94, 202) ; this division applies to the dilTerent regions sur
i-Qunding that mysterious focus of the universe, the 'Earia rov iravTot,
of the Pythagoreans. In the fragmentary passage in which this divi-
sion is found, the term Ouranos designates the innermost region, situ-
ated between the moon and earth ; this is the domain of changing
things. The middle region, where the planets circulate in an invaria-
ble and harmonious order, is, in accordance with the special coucep-
tions entertained of tlie universe, exclusively termed Cosmos, while the
word Olympus is used to express the exterior or igneous region. 13opp,
the profound philologist, has remarked, that we may deduce, as Pott
has done, Etymol. Forschungeii, th. i., s. 39 and 252 {Eiymol. Research-
es), the word Koa^og from the Sanscrit root 'sud\ purificari, by assum-
ing two conditions; first, that the Greek k in koo^oq comes from the
palatial c, which Bopp represents by 's and Pott by c (in the same man-
ner as diKa, decern, taih^m in Gothic, comes from the Indian word del-
ean), and, next, that the Indian d' corresponds, as a general rule, with
the Greek 6 ( Vergleichende Grammatik, $ 99 — Comparative Grammar),
which shows the relation of Koa/xoc (for Kodfxog) with the Sanscrit root
^sud\ whence is also derived Kada^ibg. Another Indian term for the
world is gagat (pronounced dschagat), which is, properly speaking, the
present participle of the verb gagdmi (I go), the root of which is gd.
In restricting ourselves to the circle of Hellenic etymologies, we find
{Etymol. M., p. 532, 12) that Koojiog is intimately associated with wafw,
or rather with Kacvvfiac, whence we have KeKaafievog or KCKac^fxEvog.
Welcker (Eine Kretische Col. in Thebcn, s. 23 — A Cretan Colony in
Thebes) combines with this the name Kadjiog, as in Hesychius Kud/nog
signifies a Cretan suit of anus. When the scientific language of Greece
w^as introduced among the Romans, the word mundus, which at first had
only the primary meaning of /cda/^of (female ornament), was applied to
designate the entire universe. Ennius seems to have been the first
who ventui-ed upon this innovation. In one of the fragments of this
poet, preserved by Macrobius, on the occasion of his quarrel with Vir-
gil, we fiud the word used in its novel mode of acceptation : " Micitdus
coeli vastus constitit silentio''^ (Sat., vi., 2). Cicero also says, ^'Qvem nos
lucentem mundum vocamus^^ (Timajus, 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, accord-
ing to Bopp, from Idk (to see and shine); it is the same with the Scla-
vonic root swjet, which means both light and icorld. (Grimm, Deutsche
Gramm., b. iii., s. 394 — German Grammar.) The word icelt, which
the Germans make use of at the present day, and which was weralt in
old German, toorold in old Saxon, and veruld in Anglo-Saxon, was, ac-
cording to .Tames Grimm's interpi-etation, a period ol time, an age (««-
cnlum), rather than a term used for the world in space. The Etruscans
figured to themselves mundus as an inverted dome, symmetrically op-
posed to the celestial vault (Otfried MUller's Etrusken, th. ii., s. 96,
&c.). Taken in a still more hmited sense, the word appears to have
signified among the Goths the terrestrial surface girded by seas (marei,
meri), the merigard, literally, garden of seas.
INTRODUCTION. 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 Pythago-
rean views, Philolaiis 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 Pythagoras, and in accordance with the precise
definition given of it in the treatise entitled De Mmido, which
was long erroneously attributed to Aristotle. It is the assem-
blage 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 sig-
nification, the present work ought rather to have borne the
title of Cosmography, divided into Uranography and Geog-
raj)hy. The Romans, in their feeble essays on philosophy, ^
imitated the Greeks by applying to the universe the term
inundus, which, in its primary meaning, indicated nothing
more than ornament, and did not even imply order or regu-
larity in the disposition of parts. It is probable that the in-
troduction 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 pu
pils on the Pythagorean philosophy.
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 nebula} 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 ivorld presents a pic-
ture of all that exists in space — of the simultaneous action of
* See, on Ennius, the ingenious researches of Leopold Krahnev, in
liis Grundlinien ziir GeschicJite des Verfalls der Romischen Staats-Rcii
gion, 1837, s. 41-45 (Outlines of the History of the Decay of the EstaU
lished Religion among the Romans). In all probability, Ennius did not
quote from writings of Epicharmus himself, but from poems composed
La the name of that philosopher, and in accordance wi'h his views
72 COSMOS.
natural forces, together with the phenomena which they pro-
duce.
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 for-
mation. It is not organic matter alone that is continually un-
dergoing change, and being dissolved to form new combina-
tions. 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 recog-
nizing the traces of the prior existence and destruction of an
organic world. The sedimentary rocks present a succession
of organic forms, associated in groups, Avhich have successive-
ly displaced and succeeded each other. The different super
imposed strata thus display to us the faunas and floras of dif-
ferent epochs. In this sense the description of nature is inti
mately 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 peculiar-
ly 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 {coulees) of amygdaloid with
elongated and parallel pores, and white deposits of pumice,
intermixed with black scoriae, animate the scenery by the as-
sociations of the past which they awaken, actmg 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 em-
ployed 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
INTRODUCTION. 73^
phases. It is not, however, in the definition given by Vale-
lius Flaccus,*' but in the zoological writings of Aristotle, that
the word history presents itself as an exposition of the results
of experience and observation. The physical description of
the word by Pliny the elder bears the title of Natural His-
tory, while in the letters of his nephew it is designated by the
nobler terra of History of Nature. The earlier Greek his-
torians did not separate the descriptions of countries from the
narrative of events of which they had been the theater. With
these writers, physical geography and history were long inti-
mately 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 princi-
ple, and the evidence ajSbrded by rational truths. In the
present state of empirical knowledge, we can scarcely flatter
ourselves Avith 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 gen-
eration of men will ever have cause to boast of bavins: com-
prehended 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 advance-
ment have been made manifest in our own day, in the phe-
nomena 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 reason*
* Aul. Gell.. Noct. Alt., v., 18.
Vol. I— D
74 COSMOS.
ing is applied strictly to analogous phenomena ; but as soon
as dynamical views prove insufficient M'here the specific prop-
erties and heterogeneous nature of matter come into play, it is
to he feared that, by persisting in the pursuit of laws, we may
find our course suddenly arrested by .an impassable 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 composi-
tion, so happily recognized by modern chemists, and proclaimed
under the ancient form of atomic symbols, still remains isola-
ted and independent of mathematical laws of motion and grav-
itation.
Those productions of nature which are objects of direct ob-
servation 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 distri-
bution of groups, can not rise to the height of a classification
based on one sole principle of composition and internal organ-
ization. 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 dif-
ferently graduated phases in the investigation of the external
world. Empiricism originates in isolated views, which are
subsequently grouped according to their analogy or dissimilar-
ity. To direct observation succeeds, although long afterward,
the wish to prosecute experiments ; that is to say, to evoke
phenomena under different determined conditions. The ra-
tional 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 knowl-
edge, namely, relations of quantity, comprising ideas of num-
ber and size, and relations of quality, embracing the consider-
ation of the specific properties and the heterogeneous nature
INTRODUCTION. 76
of matter. The former, as being more accessible to the exer
cise of thought, appertains to mathematics ; the latter, from
its apparent mysteries and greater difficulties, falls under the
domain of the chemical sciences. In order to submit phe-
nomena to calculation, recourse is had to a hypothetical con-
struction 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 organiza-
tion, have complicated our views generally, and shed an un-
certain light on the path we ought to pursue.
The most various forms of intuition have thus, age aftei
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 possi-
ble 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 complica-
tion of phenomena, and 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 eter-
nal 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 con-
nection, the generalization of many specialities in the great
mass of observations, or the attempt to discover laws. Con-
ceptions 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 counsels of those profound and powerful thinkers who
76 COSMOS.
have given new life to speculations which were already fa-
miliar 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 pure-
ly ideal science of nature, has been signalized by the intoxica-
tion of pretended conquests, by a novel and fantastically sym-
bolical 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 phil-
osophical pursuits and experimental sciences have remained
strangers to these saturnalia. The results yielded by an earn-
est investigation in the path of experinient can not be at va-
riance 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 act-
ually 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 cul-
tivated languages, must not lead us to separate the sphere of
nature from that of mind, since such a separation would re-
duce the physical science of the world to a mere aggregation
of empirical specialities. Science does not present its.elf 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 ex-
ternal 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 fur-
nished to it by the perceptions of the senses. Thus, in the
INTRODUCTION. 77
early ages of mankind, there manifests itself in the simple in-
tuition of natm*al facts, and in the efforts made to compre-
hend them, the germ of the philosophy of nature. These
ideal tendencies vary, and are more or less powerful, accord-
ing 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 imag-
ination.
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 pene-
trated, 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 ob-
servation, 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 per-
fected. 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 prop-
erty of mankind, and should not, 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 disad-
vantages ; we must not, therefore, be surprised if, in the per-
petual vicissitude of theoretical views, as is ingeniously ex-
pressed by the author of Giordano Bi'uno,^ " most men see
nothing in philosophy but a succession of passing meteors,
while even the grander forms in which she has revealed her-
self share the fate of comets, bodies that do not rank in pop-
ular opinion among the eternal and permanent works of na-
* SchelUug's Bruno, TJeher das Goitliche und Naturaliche Princip
der Dingc, $ 181 (Bruno, on the Divine and Natural Principle of
Things)
78 coSxMos.
ture, but are regarded as mere fugitive apparitions of igiioo«/s
vapor." We would here remark that the abuse of thought,
and the false track it too often pursues, ought not to sanctian
an opinion derogatory to intellect, vi^hich would imply that
the domain of mind is essentially a world of vague fantastic
illusions, and that the treasures accumulated by laborious ob-
servations 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 mutual connections, and at another that exercise of
the imagination which prompts and excites discoveries by its
creative powers.
COSMOS.
DELINEATION OF NATURE. GENERAL REVIEW OF
NATURAL PHENOMENA.
When the human mind first attempts to subject to its con-
trol the world of physical phenomena, and strives by medita-
tive 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 insen-
sible 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 our-
selves to be overpowered by a sense of the stupendous rich-
ness 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
aAvakened within the subjective sphere of ideas. It is by a
separation and classification of phenomena, by an intuitive in-
sight into the play of obscure forces, and b/ animated expres-
sions, in which the perceptible spectacle is i\ fleeted with vivid
truthfulness, that we may hope to compreh^^nd and describe
the universal all (to Tray) in a manner worthy of the dignity
of the word Cosmos m its signification of tiniverse, order of
the U'orld, and adornment of this universal order. May the
ijumeasurable diversity of phenomena which crowd into the
picture of nature in no way detract from that harmonious im-
pression of rest and unity v/hich is the ultimate object of every
literary or purely artistical composition.
Beginning with the depths of space and the regions of re-
motest nebulse, Vv-e 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 atten-
80 COSMOS
tion to its form, temperature, and magnetic tension, and to
consi'ler the fullness of organic life unfolding itself upon its
surface beneath the vivifying influence of light. In this man-
ner a picture of the world may, with a few strokes, be made
to include the realms of infinity no less than the minute mi-
croscopic animal and vegetable organisms which exist in stand-
ing 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 vari-
ously 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 pic-
ture 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 complete-
ness of the undertaking. The delineator of nature must re-
sist 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 proper^,
ties of matter — -or, to speak more in accordance with the lan-
guage 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 neces-
sarily prove unsuccessful. Thus, besides the pleasure derived
from acquired knowledge, there lurks in the mind of man,
and tinged with a shade of sadness, an unsatisfied longing for
something beyond the present — a striving towaixl regions yet
unknown and unopened. Such a sense of longing binds still
■aster 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 receive^ from without, and that which it reflects
from its own dej ths 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 it-
self to the haman intellect as a problem which can not be
grasped, a.nd whose solution is impossible, since it requires a
knowledge of che combined action of all natural forces. Such
an acknowledgment is due where the actual state and pro-
spective 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 ef-
fort to embrace nature in its universality may remain unsatis-
fied, the history of the contemplation of the universe (which
DELINEATION OF NATURE. 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 ex-
pression of physical laws, depend upon inean mimerical value?,.
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 at-
tainment and the rectification of the mean values of certain
quantities by means of the processes of weighing and meas-
uring ; and it may be said, that the only remaining and wide-
ly-difiused hieroglyphic characters still in our writing — nimi-
bers — 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 nu-
merical 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 rephes. 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 long-
ing 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
D2
82 COSMOS.
to distant regions. The belief in the uncommon and the won-
derful lends a definite outline to every manifestation of ideal
creation ; and the realm of fancy — a fairy-land of cosmolog-
ical, geognostical, and magnetic visions — becomes thus invol-
untarily blended vv^ith the domain of reaUty.
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 mys-
terious prototype — reveals itself to the simple mind and feel-
ings of man as something earthly, and closely allied to him-
self It is only within the animated circles of organic struc-
ture 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 uni-
verse, in which the magnitude of masses, the number of con-
gregated 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 strata ; 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," sup-
porting the vault of heaven. It begins to exercise its action
at the spot where it originated, and passes from the consider-
ation 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 mathe-
matical 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 deofree — and does not enter into a consideration of the
proofs on which such results have been based. Here, there-
fore, we do not proceed from the subjective point of view of
human interests. The terrestrial must be treated only as a
part, subject to the whole. The view of nature ought to be
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
terrestrial, but with that which fills the regions of space. But
as the sphere of contemplation contracts in dimension our per-
ception of the richness of individual parts, the fullness of phys-
ical phenomena, and of the heterogeneous properties of mat-
ter becomes enlarged. From the regions in which we rec-
ognize only the dominion of the laws of attraction, Ave de-
scend to our own planet, and to the intricate play of terrestrial
forces. The method here described for the delineation of na-
ture is opposed to that which must be pursued in establish-
ino- 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 me-
dium 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 in 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 dens-
ity and size, or scattered through space in the form of self-
luminous vapor. If we consider first the cosmical vapor dis
persed in definite nebulous spots, its state of aggregation will
84 COSMOS.
appear constantly to vary, sometimes appearing separated into
round or elliptical disks, single or in pairs, occasionally con-
nected 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, inclosing a dark interior. It is conjectured
that these bodies are undergoing variously developed formative
processes, as the cosmical vapor becomes condensed in con-
formity with the laws of attraction, either round one or more
of the nuclei. Between two and three thousand of such un-
resolvabie 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 de-
velopment, so do we also, in the great garden of the universe,
recognize 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 conject-
ure 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-exist-
ence, we have no experience, and can therefore form no con-
ception.
A comparison of the various causes influencing the develop-
ment 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 constel-
lation 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.
CELESTIAL PHENOMENA. 85
Nebulous stars must not be confounded either with irreffu-
larly-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 cir-
cular or slightly oval disks manifest in all their parts a per-
fectly 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 con-
siderable magnitude of their apparent diameter, and the re-
mote distance from which they are revealed to us, show that
both the planetary nebulte 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
nebula? are very remote nebulous stars, in which the differ-
ence between the central body and the surrounding nebulous
covering can no longer be detected by our telescopic instru-
ments.
The magnificent zones of the southern heavens, between
50° and 80°, are especially rich in nebulous stars, and in com-
pressed unresolvable nebulae. The larger of the two Magel-
lanic 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
* The optical cousiderations relative to the difTerence 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 explain-
ed in Arago's Analyse des Travaux de Sir William Herschel (Annuaire
du Bvreaii des Lang., 1842, p. 410-412, and 441).
t The twro 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 con-
densation. 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 form-
ing a luminous ground on which other objects of striking and inde-
scribable 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 unre-
solvable 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.)
86 COSMOS.
not resolvable, which, producing a general brightness in the
field of view, form, as it were, the back-ground of the picture."
The appearance of these clouds, of the brightly-beaming con-
stellation Argo, of the Milky Way between Scorpio, the Cen-
taur, 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 con-
stantly 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 nebulse of definite form, exact and corresponding observa*
tions indi^ccxe the existence and the general distribution of an
apparently non-luminous, infinitely-divided matter, which pos
sesses a force of resistance, and manifests its presence in Encke's,
and perhaps also in Biela's comet, by diminishing their eccen-
tricity and shortening their period of revolution. Of this im-
peding, 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 mat-
ter of the immeasurable regions of space {ovpavov ^oprog)*
— whether, scattered without definite form and limits, it ex-
ists as a cosmical ether, or is condensed into nebulous spots,
and becomes comprised among the solid agglomerated bodies
of the universe — we approach a class of phenomena exclusive-
ly designated by the term of stars, or as the sidereal world.
* I should have made use, in the place of garden of the universe, of
the beautiful expression xoprog ovpavov, borrowed by Hesychius fi-om
an unknown poet, if ;:j;6prof had not rather signified in general an in-
closed space. The connection with the German garten and the En-
glish garden, gards in Gothic (derived, according to Jacob Grimm, from
gairdan, to gird), is, however, evident, as is likewise the affinity with
the Sclavonic grad, gorod, and as Pott remarks, in his Etymol. Forschun-
gen, th. i., s. 144 (Etymol. Researches), with the Latin chars, 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,^ gdrd, a place inclosed, as a court, or a country
seat, and the Persian gerd, gird, a district, a circle, a princely country
Beat, a castle or city, as we find the term applied to the names of places
in Firdusi's Schahnameh, as Siyawakschgird, Darabgird, &c.
* (This word is written ^aarrf in the Danish.] — TV. ^
CELESTIAL PHENOMENA. 87
Here, too, we find diflerences existing in the solidity or density
of the spheroid ally agglomerated matter. Our own solar sys-
tem presents all stages of mean density (or of the relation of
volume to 7?iass.) 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 descendino- scale — to draw our illustration from 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 ar-
rangement 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 inves-
tigation 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 ele-
gant inscription on his monument at Upton, broke through the
inclosures of heaven {codorum perrupit claustra), and, like
another Columbus, penetrated into an unknown ocean, from
which he beheld coasts and groups of islands, whose true po-
sition 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 numeric-
al 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 ofi^er the same degree of math-
ematical certainty as that which may be attained in all that
88 COSMOS.
relaies to our solar system, whether we consider the rotation
of double stars with unequal velocity round one common cen-
ter 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 L- the obscurity of antiquity, the other in that of inac-
cessible 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 mat-
ter to be distributed in groups, either as unresolvable nebulaj
of different ages, condensed around one or more nuclei, or as
already agglomerated into clusters of stars, or isolated sphe-
roidal bodies. The cluster of stars, to which our cosmical isl-
and 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 de-
termined for the brightest star in the Centaur (0"-9128), that
hght 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 prox-
imity), that a period of nine years and a quarter is required
for the transmission of light Irom this star to our planet. Our
starry stratum is a disk of inconsiderable thickness, divided a
* 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"-0640. For 61 Cygni, see Bessel, in Schumacher's Jahr-
buch, 1839, s. 47, and Schumacher's Astron. Nachr., bd. xviu., s. 401,
402, probable mean error, 0"-0141. With reference to the relative
distances of stars of different magnitudes, how those of the third mag-
nitude may probably be three times more remote, and the manner in
which we represent to ourselves the material arrangenient of the starry
strata, I have found the following remarkable passage in Kepler's
Epitome Astronomies Copernicance, 1618, t. i., lib. 1, p. 34-39: ''Sol
hie noster nil aliud est quam una ex fixis, nobis major et clarior visa,
quia, propior quam fix a. Pone terram stare ad latus, una semi-diamctro
vim lactece, tunc hcsc via lactea apparebit circulus parvus, vet ellipsis par-
va, tota declinans ad latus alterum; eritque simul uno intuitu conspicua,
qucB nunc non potest nisi dimidia corispici quovis momcnto. Itaque fix'
arum sphcera non tantum orhe stellarum, sed etiam circulo lactis versus
nos deorsum est terminata.^^
SIDEREAL SYSTEMS. 89
third oi'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 stra-
tum 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 man-
ner 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 perspec-
tively grouped, encircling, as in a zone, the visible vault of
heaven. This narrow and branched girdle, studded with ra-
diant light, and here and there interrupted by dark spots, de-
viates only by a few degrees from forming a perfect large cir-
cle 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 tele-
scopic vision as a ring, and at a still greater distance as a re-
solvable discoidal nebula.
Among the many self-luminous moving suns, erroneously
called fixed stag's, 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 midtiple stars
(double stars or suns), these bodies are not subject, with re-
spect to relative motion and illumination, to the same planet-
ary 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 sys-
90 COSMOS.
tern the center of gravity is often comprised within the inner-
most 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 multi-
ple cluster of stars, the analogy thus suggested must be limit •
ed to the universality of the laws of attraction in different sys-
tems, 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 dis-
tance 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 j^lcmets* eighteen satel-
* [Since the publication of Bavon Humboldt's work in 1845, several
other planets have been discovered, making the number of those be-
longing to our planetary system sixteen instead of eleven. Of these,
Astrea, Hebe, Flora, and Iris are members of the remarkable group
of astei'oids between Mars and Jupiter. Astrea and Hebe were dis-
covered 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 de-
terminations 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 34 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 investigatioji 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 succeed-
ed 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
PLANETARY SYSTEMS. 91
iites 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. We may, with no inconsiderable degree of proba-
bility, include within the domain of our Sun, in the immedi-
ate sphere of its central force, a rotating ring of vaporous mat-
ter, lying probably between the orbits of Venus and Mars, but
certainly beyond that of the Earth,=^ which appears to us in
formal incompatibility between the observed motions of Uranus and
the hypothesis that he was acted on ojily by the Sun and known plan-
ets, 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 over-
whelming, he, on the 31st of August, 1846, laid before the French In-
stitute a paper, in w^hich he indicated the exact spot in the heavens
where this new planetaiy 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^ 47'; mass, ^ 3V0 ^h 5 heliocentric long., Jan. 1st,
1847, 326° 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 expect-
ed the new planet would appear, this being one of a series of maps
made for the Academy of Berlin, of the small stars along the entire zo-
diac. By means of this valuable assistance, Dr. Galle, of the Berlin
Observatory, was led, on the 25th of September, 184G, by the discov-
ery 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 lea-ding to yet
greater discoveries. It would appear from the most recent observations,
that the mass of Neptune, instead of being, as at first stated, ^ jq o^h, is
only about _^__th that of the Sun, while its periodic time is now given
w^ith 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 ac-
curate observations have been inade regarding its system of satellites.
See Trans. Astron. Soc, and The Planai Neptune, 1848, by J . P. Nicholl. 1
— Tr.
* " If there should be molecules in the zones diffused by the atmo»
92 COSMOS
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.
When we consider the complication of variously-formed bodies
which revolve round the Sun in orbits of such dissimilar ec-
centricity — although we may not be disposed, with the im-
mortal author of the Mecanique Celeste, to regard the larger
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, re-
volve with but slightly eccentric orbits round the Sun), con-
stitutes but a small portion of the whole system with respect
to individual numbers, if not to mass.
It has been proposed to consider the telescopic planets, Ves-
ta, Juno, Ceres, and Pallas, with their more closely intersect-
ing, 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. The planets near-
est 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 satel-
lites may be ascribed to Uranus, have a quantitative prepon-
derance in the number of their attendant moons, which is as
seventeen to one.
phere of the Sun of too volatile a nature either to combine Avith one
another or with the planets, we must suppose that they would, in cir-
cling round that luminary, present all the appearances of zodiacal light,
without opposing any appreciable resistance to the different bodies com-
posing the planetary system, either owing to their extreme rarity, oi*
to the similarity existing between their motion and that of the planets
with which they come in contact." — Laplace, Expos, du Syst. du MondAi
(ed. 5), p. 415.
* Laplace, Exp. du Syst. du Monde, p. 396, 414.
t Littrow, Astronomic, l8iJ5, bd. xi., § 107. Madler, Astron., 1841,
$ 212. Laplace, Exp. d*. Syst. du Monde, p. 210.
PLANETARY SYSTEMS. 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 revolv-
nig planets from the central body, and their absolute size,
density, period of rotation, eccentricity, and the inclination of
their orbits and the axes. We know as yet of no inherent ne-
cessity, no mechanical natural law, similar to the one which
teaches us that the squares of the periodic times are propor-
tional 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 vol
ume, immediately precede Jupiter (the greatest in size of an)
of the planetary bodies), if we consider them with regard to
distance from the Sun ; and yet the disks of these small aster-
oids, which scarcely admit of measurement, have an areal sur-
face not much more than half that of France, Madagascar, or
Borneo. However striking may be the extremely small dens-
ity of all the colossal planets, which are furthest removed from
the Sun, we are yet unable in this respect to recognize any
regular succession.* Uranus appears to be denser than Sat-
urn, even if we adopt the smaller mass, -34 o o 5> assumed by
Lament ; and, notwithstanding the inconsiderable difference
of density observed in the mnermost planetary group,t we find
both Venus and Mars less dense than the Earth, which lies
between them. 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 el-
* See Kepler, on the increasing density and volume of the planets in
proportion with their increase of distance from the Sun, which is de-
scribed as the densest of all the heavenly bodies ; in the Epitome As-
iron. Copern. in vii. libros digesta, 1618-1622, p. 420. Leibnitz also in-
clined to the opinions of Kepler and Otto von Guericke, that the plan-
ets 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.,
I 264.
t On the arrangement of masses, see Encke, in Schum., Astr. Nachr.
1843 Nr. 488, $ 114.
94 COSMOS.
liptic orbits of Juno, Pallas, and Mercury have the greatest
degree of eccentricity, and Mars and Venus, which immedi-
ately 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 inter-
woven.
The eccentricities of Juno and Pallas are very nearly iden-
tical, and are each 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 chmate, seasons of
the year, and length of the days depend, more than on eccen-
tricity. 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 twen-
ty-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 ir-
regular 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 sec-
ond and fourth, have been recently observed with certainty,
that the axis of this, the outermost of all the planets, is scarce-
ly incHned as much as 11° toward the plane of its orbit, while
Saturn is placed between this planet, whose axis almost coin-
cides with the plane of its orbit, and J upiter, 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 ex-
istence, 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 de-
gress 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 firgm the conflict of manifold forces acting under un-
PLANET All V SYriTEMS. 95
known conditions, although nian considers as accidental what-
ever he is unable to explain in the planetary formation on pure-
ly 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 dens-
ity, 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 difference in 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 geog-
nostic relations of the elevations of continents ; but we are un-
able from 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 ex-
istence 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 at variance with the conception of a series,
owing to the necessity for a supposition in the case of the first
member.
The hitherto discovered principal planets that revolve round
our Sun are attended certainly by fourteen, and probably by
eighteen secondary planets (moons or satellites). The princi-
pal planets are, therefore, themselves the central bodies of sub-
ordinate systems. We seem to recognize in the fabric of the
universe the same process of arrangement so frequently ex-
hibited 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 suhoi'dinate classes. The
secondary planets or satellites are more frequent in the extern-
al region of" the planetary system, lying beyond the intersect-
ing orbits of the smaller planets or asteroids ; in the inner re-
gion none of the planets are attended by satellites, with the
exception of the Earth, whose moon is relatively of great mag-
nitude, since its diameter is equal to a fourth of that of the
Earth, while the diameter of the largest of all known second-
ary 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 satelhtes are most remote from the Sun,
96 COSMOS.
and are at the same time the largest, most compressed at the
poles, and the least dense. According to the most recent
measurements of Madler, Uranus has a greater planetary
compression than any other of the planets, viz., -g-.^^d. In our
Earth and her moon, whose mean distance from one another
amounts to 207,200 miles, we find that the difierences of
mass* and diameter between the two are much less consider-
able than are usually observed to exist between the principal
planets and their attendant satellites, or between bodies of
difi'erent orders in the solar system. While the density of the
Moon is five ninths less than that of the Earth, it would ap-
pear, 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 satelHtes 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 satel-
lites, approach the nearest to the third and brightest of Jupi-
ter'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 ibrty-foot
telescope of William Herschel in 1789, and were seen again
by John Herschel at the Cape of Good Hope, by Vice at Rome,
and by Lamont at Munich. Determinations of the true di-
ameter of satellites, made by the measurement of the apparent
size of their small disks, are subjected to many optical diffi-
culties ; but numerical astronomy, whose task it is to prede-
termine by calculation the motions of the heavenly bodies as
they will appear when viewed from the Earth, is directed al-
* If, according to Burckhardt's determination, the Moon's radius be
0.2725 and its volume _-J;_-^th, its density will be 0*5596, or nearly five
ninths. Compare, also, Willi. Beer und H. Madler, der Mond, § 2,
10, and Madler, Ast., § 157. The material contents of the Moon are,
according to Hansen, nearly ^^th (and according to Madler ^i._-th)
that of the Earth, and its mass equal to g^.^^ d that of the Earth. lu
the largest of Jupiter's moons, the third, the relations of volume to the
central body are -r^^..-„th, and of mass --A_._th. On the polar flatten-
, *' 1 .■> .< 7 1 1 J U *
mg ot Uranus, see Schum., Aalron. Nachr., 1844, No. 493.
PLANETARY SYSTEMS. 97
most, 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 vv^hich 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 dis-
tance between Uranus and its sixth satellite (if the latter real-
ly exist) amounts to as much as 1,360,000 miles. If we com-
pare, in each of these subordinate systems, the volume of the
main planet with the distance of the orbit of its most remote
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 satel-
lite 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 Madler
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-di-
ameters 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 ^d
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 hkewise 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 move like the
primary planets from west to east, and in elliptic orbits, do-
Vol. I.— E
98 COSMOS.
viatiiig but little from circles. It is only in the case of ouf
moon, and perhaps in that of the first and innermost of tha
satellites of Saturn (0'068), that we discover an eccentricity
greater than that of Jupiter ; according to the very exact ob-
servations of Bessel, the eccentricity of the sixth of Saturn's
satellites (0'029) exceeds that of the Earth. On the extremes!
limits of the planetary system, vv^here, 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
have certainly been but imperfectly investigated) exhibit tht
most striking contrasts from the facts observed with regard t(?
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 regard-
ed as a fusion of agglomerated satellites) moving from west tc
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 plan-
etary atmospheric vapor, there must have existed singular
causes of retardation or impediment in the vaporous rings re-
volving round Uranus, by which, under 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 slight
variations in the revolution, give rise -to fluctuations of from
6'^ to 8*^, 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 tlie west-
ern or southern at another. By means of this libration* we
ave enabled to see the annular mountain Malapert (which oc-
casionally conceals the Moon's south pole), the arctic land-
scape round the crater of Gioja, and the largf gray plane near
Endymion, which exceeds in superficial extent the Mare Va-
pormn. Three sevenths of the Moon's surface arc entirelj
* Beer and Madler, op. cit., $ 185, s. 208, and *;j 347, s 33-J ; ,muI u
their Phys. Kemiiniss der liimml. Korper, s. 4 uiiiJ 69. Tab. 1 ( l*hy&Jo
al History of the Heavenly Bodies).
COMETS. 9i>
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 do-
main 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, toi
the human mind, appearing, from time to time, either glim-
mering in true or delusive hght. We have hitherto consid-
ered 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 to-
gether by mutual attraction ; it therefore now only remains
lor us to speak of the unnumbered host of comets which con-
stitute a portion of the cosmical bodies revolving in independ-
ent orbits round the Sun. If we assume an equable distribu-
tion 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 esti-
mates on the rules of the calculus of probabilities, we shall
obtain as the result an amount of myriads perfectly astonish-
ing. 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. =^
* The first comets of whose orbits we have any knowledge, and
which were calculated from Chinese observations, are those of 240 (un-
der Gordian III.), 539 (under Justinian), 56-5, 568, 574, 837, 1337, and
1385. See John Russell Hind, in Schiini., Astron. Nachr., 1843, No. 498.
While ihe comet of 837 (which, a^cordin^ to Du Sejour, continued dur-
100 COSMOS.
Although comets have a smaller mass than anj^ other oos-
mical bodies — being, according to our present knowledge, prob-
ably not equal to joVo^h part of the Earth's mass — yet they
occupy the largest space, as their tails in several instances ex-
tend over many millions of miles. The cone of luminous va-
por 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 rath
er to appertain to the individual than the class, that a de-
scription of one of these " wandering light-clouds," as they
were already called by Xenophanes and Theon of Alexandria,
cotemporaries 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 concentrated toward the middle. This is the most
simple type ; but it can not, however, be regarded as rudi-
mentary, since it might equally be the type of an older cos
mical 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 de
nominated 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,
ing 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 him
self 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°, 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 cor.Ti-
et, 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 Laugier, Comptes Rendus des Stances de VAcad., 1843, t. xvi.,
1006.
* 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 Feb-
raary (according to the testimony of J. G. Clarke, of Portland, state of
COMETS. 101
lor instance, in the large comets of 1402, 1532, 1577, 1744,
and 1843. This latter circumstance indicates, in particular
individuals, a denser mass, capable of reflecting Ught with
greater intensity. Even in Herschel's large telescope, only
two comets, that discovered in Sicily in 1807, and the splen-
did one of 1811, exhibited well-defined disks ;* the one at an
angle of 1", and the other at 0""77, whence the true diame-
ters are assumed to be 536 and 428 miles. 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 con-
tinued visible for so long a period, the nucleus and its nebu-
lous 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, bright-
ly shining zones being in many cases separated by concentric
nebulous envelopes. The tails sometimes appear single, some-
times, although more rarely, double ; and in the comets of-
1807 and 1843 the branches were of difierent leno^ths ; in
one instance (1744) the tail had six branches, the whole
forming an angle of 60^. The tails have been sometimes
straight, sometimes curved, either toward both sides, or to-
ward 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 ap-
peared 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 or less thick-
Maiue), between 1 and 3 o'clock in the afternoon.* The distance of
the very dense nucleus from the sun's light admitted of being measured
with much exactness. The nucleus and tail a{)peared like a very pure
white cloud, a darker space intervemng between the tail and the nu-
cleus. {Amer- Journ. of Science, vol. xlv., No. 1, p. 229.)
* 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 <inJ 428 En
glish miles. For the magnitudes of the comets of 1798 and ISOJ. st;e
Arago, Annnaire, 1832, p. 203.
a [The translator was at New Bedford, Massachusetts, U. S., on the 2Sth Februa-
ry, 1843, and distinctly saw the comet, between 1 and 2 in the afternoon. The skj
at the time was intensely blue, and the sun shining with a dazzling brightnoos un-
known in European climates.] — Tr
102 * COSMOS.
ness, and, considered in this manner, they furnish a simple
explanation of many of the remarkable optical phenomena al-
ready 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°), 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 be-
ing bent backward, formed a part of the tail. The nucleus
of Halley's comet, with its emanations, presented the appear-
ance of a burning rocket, the end of which was turned side-
ways 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.*
The great Konigsberg astronomer concluded from many meas-
urements, 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 opin-
ion that they indicate a polar force, which turns one semi-di-
ameter of the comet toward the Sun, and strives to turn the
opposite side away from that luminary. The magnetic polar-
ity 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 equi-
noxes." This is not the place to enter more fully upon the
grounds on which explanations of this subject have been bas-
ed ; but observations so remarkable,! and views of so exalted
* Arago, Des Changemenis physiques de la Comete de Halley du 15-
23 Oct., 1835. Annnaire, 1836, p. 218, 221. The ordinary direction
of the emanations was noticed even in Nero's time. " Comce radios sO'
lis effugiunt.^^ — Seneca, Nat. Qucest., vii., 20.
t Bessel, in Schumacher, Astr. Nachr., 1836, No. 300-302, s. 188, 192,
COMETS. 103
I character, regarding the most wonderful class of the cosmic-
al bodies belonging to our solar system, ought not to be en-
tirely passed over in this sketch of a general picture of nature.
Although, as a rule, the tails of comets increase in magni-
tude and brilliancy in the vicinity of the sun, and are directed
away from that central body, yet the comet of 1823 ofiered
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°. 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 occa-
sioned a double, unchecked, continuous emanation of nebulous
matter,*
Aristotle, in his Natural Philosophy^ makes these emana-
tions 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, in-
candescent matter. The nebulous belt which separates the
different portions of the vault of heaven was therefore regard-
ed by the Stagirite as a large comet, the substance of which
was incessantly being renewed.!
197, 200, 20-2, 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). Duulop, at Paramat-
ta, thought the same with reference to the third comet of 1825.
* Bessel, in Astr. Nachr., 1836, No. 302, s. 231. Schum., Jahrb., 1837.
s. 175. See, also, Lehmaun, Ueber Cometenschiceife (On the Tails of
Comets), in Bode, Astron. Jahrb. fur 1826, s. 168.
t 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 approxima-
ting 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, accord-
ing to which these cosmical bodies are supposed to be planets having
long periods of revolution. (Aristot., i., 6, 2.) This Pythagorean doc-
trine, which, according to the testimony of ApoUonius Myndius, was
still more ancient, having oingiuated with the Chaldeans, ])a3scd 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. Qucest., vii., 17: ^^ Comeles
pon est species falsa, sed propHum sidus sicnt solis et lunce : altiora mnn-
di secat et tunc demum apparct quum in imum cwrsum stii venil;^' and
'Again (at vii., 27), " Cometes ceternos esse et sortis ejvsdem, cvjns ctr.tera
104 C0SM09.
The occultat.ion of the fixed stars by the nucleus of a com
et, 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 occultation 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. 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 experi-
encing any deflection during its passage.! If such an absence
of refracting power must be ascribed to the nucleus of a com-
et, tve 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
{sidera), etiamsi faciem illis non habent similemJ''' Pliny (ii., 25) also re-
fers to Apollonius Myndius, when he says, "-Sunt qui et kcBC sidera per-
petua esse credant sitoque amhitu ire, sed non nisi relicta a sole cerniy
* Olbers, in Asir. Nachr., 1828, s. 157, 184. Arago, De la Constitu-
tion physique des C o metes ; Annuaire de 1832, p. 203, 208. The an-
cients were struck by the phenomenon that it was possible to see
through comets as throusrh a flame. The earliest evidence to be met
with of stars having been seen throngh comets is that of Democntus
(Aristot., Metear., i., 6, 11), and the statement leads Aristotle to make
the not miimportant remark, that he himself had observed the occulta-
tion of one of the stars of Gemini by Jupiter. Seneca only speaks de-
cidedly of the transparence of the tail of comets. " We may see," says
he, "stars through a comet as through a cloud (Nat. Qucest., vii., 18);
but we can only see through the rays of tlie tail, and not through the
body of the comet itself: non in ea parte qua sidns ipsum est spissi et
:^olidi ignis, sed qua varus splendor occurrit et in crines dispergitur. Per
intervalla ignium, non per ipsos, vides" (vii., 26). The last remark is
unnecessary, since, as Galileo observed in the Saggialore {Lettera a
Monsignor CesaHni, 1G19), we can certainly see through a flame when
it is not of too great a thickness.
t Bessel, in the Astron. Nachr., 1836, No. 301, s. 204, 206. Struve,
in Recueil des Mim. de V Acad, dc St. Petcrsh., 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 Imghtest point of the comet.
The star remained continually visible, and its hght was not perceptibly
diminished, while the nucleus of the comet tfeemed to be almost extin
guished before the radiance of the small star of the ninth or tenth mag
nitude."
COMETS. 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 pos-
sess on the nature and the light of comets are due to Arago's
polarization experiments. His polariscope instructs us re-
garding the physical constitution of thfe Sun and comets, indi-
cating whether a ray that reaches us from a distance of many
millions of miles transmits light directly or by reflection ; and
if the former, whether the source of light is a sofld, a liquid,
or a gaseous body. His apparatus was used at the Paris Ob-
servatory in examining the hght of Capella and that of the
great comet of 1819. The latter shov/ed polarized, and there-
fore reflected hght, while the fixed star, as was to be expect-
ed, appeared to be a self-luminous sun.* The existence of
polarized cometary light announced itself not only by the in-
equality 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, de-
duced 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 ui-
dependent light seems very probable.
The variable intensity of light in comets can not always be
* 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 ap
pearance 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 com-
et in 1835, the instrument was altered so as to give, according to Ara-
go's chromatic polarization, two images of complementary colors (gieen
and red). {Annates 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 po-
larized, that is, coming from the sun. It can not be stated with abso-
lute 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."
E 2
106 COSMOS.
explained by tlie 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 in-
creased 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 dif-
ferent degrees of distance from the Sun, appears very striking.
The physical explanation of the phenomenon can not, howev-
er, be sought in the condensed layers of cosmical vapor occur-
ring in the vicinity of the Sun, since it is difficult to imagine
the nebulous envelope of the nucleus of the comet to be vesic-
ular and impervious to the ether.*
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 ex-
istence of a comet of so short a period of revolution that it re-
mains entirely within the limits of our planetary system, at-
taining 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, al-
though with difficulty, been observed by the naked eye, as in
Europe in 1819, and, according to Riimker, in New Holland
in 1822. Its period of revolution is about S^d 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 lyVl^h. days. The attempt to
brmg 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 diminishes 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 as-
* Arago, in the Anniiaire, 1832, p. 217-220. Sir John Herschel,
Asiron., § 488.
COMElfc'. 107
bribed to tlie altered form of the small nebulous star in the
vi(dnity of the Sun, and to the action of the unequal density
of the strata of cosmical ether. ^ These facts, and the inves-
tigations to which they have led, belong to the most interest-
ng results of modern astronomy. Encke's comet has been
the means of leading astronomers to a more exact investiga-
tion of Jupiter's mass (a most important point with reference
\o the calculation of perturbations) ; and, more recently, the
eourse of this comet has obtained for us the first determina-
tion, although only an approximative one, of a smaller mass for
Mercury.
The discovery of Encke's comet, which had a period of only
3id years, was speedily followed, in 1826, by that of another,
Biela'a comet, whose period of revolution is 6|th 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 cer-
tain example of the orbit of a comet intersecting that of the
Earth. This position, with reference to our planet, may there-
fore 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 en-
dowed with enormous velocity may certainly exercise a con-
siderable power ; but Laplace has shovi^i that the mass of the
comet of 1770 is probably not equal to jo'oo'tb of that of the
Earth, estimating further with apparent correctness the incan
mass of comets as much below yoo-Vo nth that of the Earth,
or about yoVo^b that of the Moon.f 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 pas-
sage took place, on the 29th of October, 1832, it required a
full month before the Earth would reach the point of inter-
section of the two orbits. These two comets oi" short periods
of revolution also intersect each other, and it has been justly
observed,! that amid the many perturbations experienced by
* Encke, in. the Astronomische Nachrichf en, 1843, No. 489, s. 130-132.
■hLaplace, Expos, du S^/st. du Monde, p. 216, 237.
X Littrow, Beschreibende Asiron,, 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, Asiron. Nachr., 1844, No. 495.
Regarding the supposed identity of the comet of 1766 with the third
108 COSMOS.
such small bodies from the larger planets, there is di. possibility
— supposing" a meeting of these comets to occur in October — •
that the inhabitants of the Earth may witness the extraordi-
nary 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.
Events of this nature, resulting either from deflection occa-
sioned by disturbing masses or primevally intersecting orbits,
must have been of frequent occurrence in the course of mill-
ions of years in the immeasurable regions of ethereal space ;
but they must be regarded as isolated occurrences, exercising
no more general or alterative effects on cosmical relations than
the breaking forth or extinction of a volcano within the limit-
ed sphere of our Earth.
A third interior comet, having likev/ise 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 Gold-
schmidt, passes beyond the orbit of Jupiter, is one of the few
whose perihelia are beyond Mars. Its period of revolution is
7y-/o years, and it is not improbable that the form of its pres-
ent 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 iden-
tical 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
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 of the last
mentioned work.
COMETS. 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 Ol-
bers'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 hav-
ing recently been proved by Laugier's calculations,* that in
the Chinese table of comets, first made known to us by Ed-
ward 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.
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 respect-
ively 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 ve-
locity 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 fur-
thest 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
* Laugier, in the Comptes Rendus des Stances de f Academie, 18431
t xvi., p. 1006.
110 COSMOS.
times that of Uranus, while a Centaiiri is 11,000, and 61
Cygni 31,000 times that of Uranus, according to Bessel's de-
terminations.
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 Burck-
hardt's comet of 1770, so celebrated on account of the disturb-
ances 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 only six times
that of the Moon. The same comet passed twice, viz., in
]769 and 1779, through the sj^stem of Jupiter's four satellites
without producing the slightest notable change in the well-
known orbits of these bodies. The great comet of 1680 ap-
proached 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 possi-
ble evils threatened by comets have acquired more weight as
their direction has become more defuiite. The certainty that
there are within the known planetary orbits comets which re-
visit our regions of space at short intervals — that great dis-
turbances 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 equiv-
alent, both as to number and variety, to the vague fears en-
tertained in early ages of the general conflagration of the world
hy Jiammg stvords, and stars with fieri/ streaming hair. As
the cons'Dlatory considerations which may be derived from the
calculus of probabilities address themselves to reason and to
AEROLITES. Ill
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 ex-
citino-. It is an inherent attribute of the human mind to ex-
perience fear, and not hope or joy, at the aspect of that which
is unexpected and extraordinary.* 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 terres-
trial 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 ob-
served, has not been able to shake the common belief in the
meteorological myth of the existence of wandering stars capa-
ble of radiating heat.
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 aeTolites, or meteoric
stones,^ when they reach our atmosphere in a fragmentary
condition. If I should seem to dwell on the specific enumer-
ation of these bodies, and of comets, longer than the general
nature of this work might w^arrant, I have not done so unde-
signedly. The diversity existing in the individual character-
istics of comets has already been noticed. The imperfect
knowledge we possess of their physical character renders it
* Fries, Vorlesungen uber die SternJcunde, 1833, s. 262-267 (Lectures
on the Science of Astronomy). An infeUcitously chosen instance of the
good omen of a comet may be found in Seneca, Nat. Qucest., vii., 17 and
21. The philosopher thus writes of the comet: " Quern 7ios Neronis
principatu Icetissimo vidimus et qui cometis detraxit infamiam.^'
t [Much valuable information may be obtained regarding the origin
and composition of aerolites or meteoric stones in Memoirs on the sub-
ject, by Baumbeer and other writers, in the numbers of Poggendorf's
Annalen, from 1845 to the present time.] — Tr.
1 12 COSMOS.
difficult; in a work like the present, to give the proper def^ree
of circumstantiality to the phenomena, which, althougL of
frequent recurrence, have been observed with such various de-
grees of accuracy, or to separate the necessary from the acci-
dental. It is only with respect to measurements and compu-
tations 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 differencef
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 cir-
cumstantiality 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 con-
dition, and frequently let fall more or less strongly heated stony
fragments, covered with a shining black crust. When we
enter mto a careful investigation of the facts observed at those
epochs when showers of shooting stars fell periodically in Cu-
mana in 1799, and in North America during the years 1833
and 1834, we shall find XhdX 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 explod-
ing smoking luminous fire-balls are sometimes seen, even in
the brightness of tropical daylight,* equaling in size the ap-
* A friend of mine, much accustomed to exact trigonometrical meas-
urements, was in the year 1788 at Popayan, a city which is 2^ 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 tlie 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 exjiress the^e i>iie-
uomena : the Germans use the w^ord Sternschnnppe, literally star savff
—an expression well suited to the physical views of the vulgar in former
AEROLITES. 1]3
parent diameter of the Moon, innumerable quantities of shoot-
ing 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 pliosiohorescent lines.^
It still remains undetermined 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
times, according to which, the lights in the finnament were said to under
go a process of snuffing or cleaning ; and other nations generally adopt a
term expressive of a shot ov fall of stars, as the Swedish stjernjfall, the
Italian stella cadente, and the English star shoot. In the woody district
of the Orinoco, on tlie dreary banks of the Cassiquiare, I heard the na-
tives in the Mission of Vasiva use terms still more inelegant than the
German star snnff. {Relation Historique du Voy. aux Rigions Equhwx.,
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 Parcse, 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 Mytlwlogie, 1843, s. 685.
* 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 tire-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 blend-
ing with the higher ether," expresses himself, however, generally with
much caution. He says: " Stellce cadentes sunt materia viscida inflam-
mata. Eai"nm aliqufs inter cadendum absumuntur, aliquce vere in terram
cadunt. pondere sua tractce. Nee est dissimile vero, quasdam conglohataa
esse ex materia fcecidentd, in ipsam auram atheream immixta : exque
aetheris regione, tractu rectilineo, per aerem trajicerc, ceu minutos com-
etas, occulta causa motus utrorumque.^^ — Kepler, Epit. Astron. Coper-
nicance, t. i., p. 80.
t 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 gi-eater 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 contin-
ues longer visible. The influence exercised on shooting stars by the
character of the atmosphere is shown occasionally even in our temper-
ate zone, and at veiy small distances apart. Wartmann relates that on
the occasion of a November phenomenon at two places lying very near
114 COSMOS.
enables the eye to penetrate furtlier into distance. Sir Alex-
ander Burnes likewise extols as a consequence of the purity of
the atmosphere in Bokhara the enchanting and constantly-re-
curring spectacle of variously-colored shooting stars.
The connection of meteoric stones with the grander phe-
nomenon of fire-halls — the former being known to be project-
ed 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 aerolites at Barbotan, in the
Department des Landes (24th July, 1790), at Siena (16th
June, 1794), at Weston, in Connecticut, U. S. (14th Decem-
ber, 1807), and at Jnvenas, in the Department of Ardeche
(15th 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
each other, Geneva and Aux Plancliettes, the number of the meteors
counted wei'e as 1 to 7. (Wartmann, Mem. sur les Eloiles Jilanies, 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 w^hole 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 Krusen-
stern saw, in his voyage round the world, the train of a fire-ball shine
for an hour after the luminous body itself had disappeared, and scarce-
ly move throughout the whole time. {Reise, th. i., s. 58.) Sir Alex-
ander Bumes gives a charming description of the transparency of the
clear atmosphere of Bokhara, which was once so favorable to the pur-
suit of astronomical observations. Bokhara is situated in 39° 43' 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 clear-
ness 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, as-
suming every color — fiery red, blue, pale, and faint. It is a noble
country for astronomical science, and great must have been the ad-
vantage 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. Mathim., Novem., 1837, p. 447); this number is,
however, limited to five or six by that diligent observer, Olbers.
(Schum., Jahrh., 1838, s. 325.)
AEROLITES. 115
nave been liiirled from one of these moving clouds. In less
frequent cases, as in that which occurred on the 16th of Sep-
tember, 1843, at Kleinwenden, near Miililhausen, a large
aerolite 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
iiameter scarcely equal to that of the small fire-works called
Eloraan candles.
The formative power, and the nature of the physical and
chemical processes involved in these phenomena, are questions
ill equally shrouded in mystery, and we are as yet ignorant
tvdiether the particles composing the dense mass of meteoric
itones are originally, as in comets, separated from one another
\n the form of vapor, and only condensed v/ithin the fiery ball
when they become luminous to our sight, or whether, in the
ease of smaller shooting stars, any compact substance actually
Tails, or, finally, whether a meteor is composed only of a smoke-
like dust, "containing iron and nickel ; while w^e 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.*
* Oil meteoric dust, see Arago, in the Annuaire for 1832, p. 254. 1
have very recently endeavored to show, in another work {Asie Centrale,
t. i., p. 408), how the Scythian saga of the sacred gold, which fell burn-
ing from heaven, and remained in'the possession of the Golden Horde
of the ParalattB (Herod., iv., 5-7), probably originated in the vague rec-
ollection of the fall of an aSrolite. The ancients had also some strange
fictions (Dio Cassius, Ixxv., 1259) of silver which had fallen from heav-
en, and with which it had been attempted, under the Emperor Seve-
rus, to cover bronze coins ; metallic iron was, however, known to exist
hi meteoric stones. (Plin., ii., 56.) The frequently-recui'ring expres-
sion lapidibus phiit must not always be understood to refer to falls of
aSrolites. In Liv., xxv., 7, it probably refers to pumice (rapil/i) eject-
ed from the volcano, Mount Albanus (Monte Cavo), which vC-as 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 myth-
ically 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 eject-
ed 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 ^Eschylus, the Promeihetis
Delivered, every thing proceeds, however, in part of the narration, as
in a fall of aerolites, for Jupiter draws together a cloud, and causes the
"district around to be covered by a shower of round stones " Posido-
116 COSMOS.
We can ascertain by measurement the enormous, wonder,
ful, and wholly planetary velocity of shooting stars, fire-balls,
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, how-
uius even ventured to deride the geognostic myth of the blocks and
stones. The Lygian field of stones was, however, very naturally and
well described iSy the ancients. The district is now known as La Crau.
(See Guerin, Mesures Baromitriques dans les Alpes, et Metiorologie
d^ Avignon, 1829, chap, xii., p. 115.)
* The specific weight of aerolites varies from 1-9 (Alais) to 4-3
(Tabor). Their general density maybe set down as 3, water being 1.
As to wliat has been said in the text of the actual diameters of fire-balls,
we must remark, that the numbers have been taken froin the few
measurl&ments 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 iu
diameter. Brandes {UnterhaltHugen, bd. i., s. 42) ascribes a diameter
varying from 80 to 120 feet to shooting stars, and a luminous train ex-
tending from 12 to 16 miles. There are, however, ample optical caus-
es for supposing that the appai'ent diameter of fire-balls and shooting
stars has been very much overrated. The volume of the largest fiie-
ball yet observed can not be compared with that rf Ceres, estimating
this planet to have a diameter of only 7J English miles. (See the
generally so exact and admirable treatise, i )n the Connection of the
Physical Sciences, 1835, p. 411.) With the view of elucidating what
has been stated in the text regarding the large aerolite that fell into
the bed of the River Narni, but has not again been found, I will give
the passage made known by Pertz, trom the Chronicon Benedicti, Man-
achi Sancti Andrece in Monte Soracte, a MS. belonging to the tenth
century, and preserved in the Chigi Library at Rome. The barbaious
Latiji of that age has been left unchanged. '^^ Anno 921, temporihns
domini Johannis Decimi pape, in anno pontificatus illius 7 visa sunt sig-
na. Nam juxta urbem Romani lapides plurimi de cailo cadere visi sunt.
In civitate qua; vocatur Narnia tarn diri ac tetri, ut 7iihil aliitd credatur,
quarn de infernalibiis locis dedncti essent. Nam ila ex illis lapidibus
umis omnium maximns est, ut d-]cidens in fluuien Narnvs, ad mensuram
unius c'uhiti super aquas fiumim ', usque hodie videretur. Nam et ignitiB
faculce de coslo plurimoe omnibus in hac civitate Romani popuH vis<e S7int,
ita ut pene terra contingeret. Alice cadentes,^'' &c. (Pertz, Mmivm.
Germ. Hist. Scriptores, t. iii., p. 715.) On the aerolites of ^gos. I'ota-
mos, which fell, according to the Parian Chronicle, in the 78 1 Olym-
piad, see Bockh, Corp. Jnscr. Graec, t. ii., p. 302, 320, 340; also Aris-
tot., Meteor., i., 7 (Ideler's Comm., t. i., p. 404-407) ; Stob., Eel. Phys.,
I., 25, p. 508 (Heeren); Pint., Lys., c. 12; Diog. Laert., ii., 10; and
see, also, subsequent notes in this work. According to a Moui^oliun
tradition, a black fragment of a rock, forty feet in height, fell iVoni
heaven on a plain near the source of the Great Yellow River in West-
ern China. (Abel Remusat, in Lametherie, Jour, de Phys., 1819, Mai
p. 264.)
AEROLITES. 117
ever, 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 ap-
parent diameter of which we may, in the case of the largest,
estimate that the actual diameter varies from 500 to about
2800 feet. 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|- 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 m which Socrates was born, has been de-
scribed 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 dif-
ficult to destroy, may be found, since the region in which it
fell is now become so easy of access to European travelers.
The huge aerolite which in the beginning of the tenth centu-
ry 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 or
a dark cloud.
On considering the enormous velocity with \Vhich, as has
been mathematically proved, meteoric stones reach the earth
from the extremest confines of the atmosphere, and the length-
ened course traversed by fire-balls through the denser strata
of the air, it seems more than improbable that these metallif-
erous stony masses, containing perfectly-formed crystals of oli-
vine, labradorite, and pyroxene, should in so short a period of
time have been converted from a vaporous condition to a solid
nucleus. Moreover, that which falls from meteoric masses,
even where the internal composition is chemically difierent,
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 1
Here, as in the sphere of organic life, all that appertains to
the history of development remains hidden in obscurity. Me-
teoric masses become luminous and kindle at heights which
118 COSMOS.
must be regarded as almost devoid of air, or occupied by an
atmosphere that does not even contain To"oVoo*h part of oxy
gen. The recent investigations of Biot on the important phe
nomenon of twihght=^ have considerably lowered the lines
which had, perhaps with some degree of temerity, been usual
ly termed the boundaries of the atmosphere ; but processes of
hght may be evolved independently of the presence of oxygen,
and Poisson conjectured that aerolites were ignited far beyond
the range of our atmosphere. Numerical calculation and geo-
metrical 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. Although Halley pronounced the great fire-ball of 1686,
whose motion was opposite to that of the earth in its orbit, f to
be a cosmical body, Chladni, 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. J A brilliant confirmation of the cos-
mical 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 cele-
brated fall of shooting stars on the night between the 12th
* Biot, TraiU d' Astro7iomie Physique (3eme 6d.), 1841, t. i., p. 149,
177, 238, 312. My lamented frieud Poisson endeavored, in a singular
manner, to solve the difficulty attending an assumption of the sponta-
neous 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 usually done, the incandescence of aerolites 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, ex-
tending far beyond the mass of our atmosphere, yet subject to terres-
trial 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 im-
ponderable 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 Probability des Jugements, 1837, p. 6.)
t Philos. Transact., vol. xxix., p. lGl-163.
X The first edition of Chladni's important treatise, Ueber den Ur-
sprung der von Pallas gefundenen nnd 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 Gottingen Taschenbnch, tha
" stones reach our atmosphere from the remoter regions of space.'
Comp., also, Olbers's letter to Benzenberg, 18th Nov., 1837, in Ben
zenberg's Treatise on Shooting Stars, p. 186.
AEROLITES. 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 y 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 observ-
ation. Such an independence of the, Earth's rotation shows
that the luminous body must have reached our atmosphere from
witlwut. According to Encke's computation* of the whole
* Eucke, \i\Vo^§,end., Annalen, bd. xxxiii. (1834), s. 213. Arago,
in the Annuaire. for 1836, p. 291. Two letters which I wrote to Ben-
zenberg, May 19 and October 22, 1837, on the conjectural precession
of the nodes in the orbit of periodical falls of shooting stai's. (Benzen-
berg'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 Fryehn, in
the Bull, de V Academie de St. PHershourg, t. iii., p. 308.')
On the 21st Oct., O.S., 1366, " die sequente post festum XL ynillia Vir-
ginum ab hora matutiyia usque ad Tioram primam visce sunt quasi stellce
de coilo cadere contiinio, et in tanta multitudine, quod nemo narrare suf
jicit.'''' This remarkable notice, of which we shall speak more fully in
the subsequent part of this w^ork, was found by the younger Von Bo-
guslawski, in Benesse (de Horowic) de Weitmil or Weithmiil, Chron-
icon Ecclesice Pragensis, p. 389. This chronicle may also be found in
the second part of ScHptores rerum Bghemicarum, by Pelzel and Do-
browsky, 1784. (Schum., Astr. Nachr., Dec, 1839.)
On the night between the 9th and 10th of November, 1787, many fall-
ing stars were observed at Manheira, Southern Germany, by Hemmer.
(Kamtz, Meteor., th. iii., s. 237.)
After midnight, on the 12th of November, 1799, occurred the extra-
ordinary fall of stars at Cumana, which Bonpland and myself have de
scribed, 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, inter-
mingled with fire-balls, were seen in large numbers by Kloden, at
Potsdam. (Gilbei-t's Ann., bd. Ixxii., s. 291.)
On the I3th of November, 1831, at 4 o'clock in the morning, a great
shower of falling stars was seen by Captain Berard, on the Spanish
coast, near Carthagena del Levante. {Annuaire, 1836, p. 297.)
In the night between the 12th and 13tli of November, 1833, occurred
the phenomenon so admirably described by Professor Olmsted, iu
North America.
In the night of the 13-14th of November, 1834, a similar fall of shoot-
120 COSMOS.
Qumber 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. On the recurrence of falls of shoot-
ing 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 the Earth
was then moving. This peculiarity of the phenomenon, mani-
fested 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 problem-
atical 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. =^ 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
jng 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 I'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.)
* I am well aware tliat, amoug 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.
(Bi'andes, Unterhaltungen fur Frennde der Astronomic mid Physik, heft
i., s. 48. Instructive Nairatives for the Lovers of Astronomy and Phys-
ics.) But Olbers considered that all determinations for elevations be-
yond 120 miles must be doubtfid, owing to the smallness of the parallax.
t 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
AEROLITES. 121
of fire-balls and shooting stars, wliicli has frequently been ob-
served to be opposite to that of" the Earth, ma}^ be considered
as conclusive arguments against the hypothesis that aerolites
derive their origin from the so-called active lunar volcanoes.
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 imag-
ine the reaction of the interior of a planet on its crust ten or
even a hundred times greater than that of our present terres-
• trial volcanoes ; the direction of masses projected from a satel-
lite 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 ori-
gin of meteoric stones* depends upon a number of conditions
* Chladui states that an Italian physicist, Paolo Maria Terzago, on
the occasion of the fall of an aerolite at Milan in 1660, by which a Fran-
ciscan monk was killed, was the first who surmised that aerolites were
of selenic origin. He says, in a memoir entitled Musceuvi Septalianum,
Manfredi Septalcs, Patricii Mediolanensis, indjistrioso labore conslruciurn
(Tortona, 1664, p. 44), '^Labant philosophorum meutes sub horum lapidum
ponderibus ; ni dicire velimus, lunam terram alteram, sine mundum esse,
ex cujus montibus dwisa frustra in inferior em nostrum hunc orbe^n dela
bantury 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 tangen-
tial force that would be requisite to bring to the Earth masses project-
ed 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 w^as 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. La-
place states that this velocity is only five or six times as great as that of
a cannon ball; but Olbers has sliown "that, with such an initial veloc-
ity 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
geogi'aphical mile). But the measured velocity of meteoric stones av-
erages 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 La-
place asserted." (Olbers, in Sebum., Jahrb., 1837, p. 52-58; and in
Vol. I.— F
12*2 COSMOS.
whose accidental coincidence could alone convert a possible
into an actual fact. The view of the orighial existence of
Gehlei-, NeuesPhyslk. Worterbuche, bd. yi., abth. 3, s. 2129-2130.)^ 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 present-
ed by Mtna, found that the greatest velocity of any of the stones pro- '
jected 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 aerolites, " that in all probability they
come from the depths of space," yet we see from another passage
(chap, vi., p. 233) that, being probably unacquainted with the extra-
ordinary planetary velocity of meteoric stones, he inclines to the hy-
pothesis of their lunar origin, always, however, assuming that the stones
projected from the Moon " become satellites of our Earth, describing
around it more or less eccentric orbits, and thus not reaching its atmos-
phere until several or even many revolutions have been accomplished."
As an Italian at Tortona had the fancy that aerolites 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 iEgos Potamos (see note, p. 116). Pliny,
whose labors in recording the opinions and statements of preceding
writei'S are astonishing, repeats the theoiy, and derides it the more
freely, because he, with earlier writers (Diog. Laert., 3 and 5, p. 99,
Hiibner), accuses Anaxagoras of having predicted the fall of aerolites
from the Sun: "Celebrant Grseci Anaxagoram Clazomenium Olyra-
piadis septuagesimae octavse secundo anno praedixisse caelestium littera-
rum scientia, quibus diebus saxum casurum esse e sole, idque factum
interdiu in Thracife parte ad iEgos flumen. Quod si quis prsedictum
credat, simul fateatur necesse est, majoris miraculi divinitatem Anax-
agorae faisse, solvique rerum naturae intellectum, et confundi omnia, si
aut ipse Sol lapis esse aut unquam lapidem in eo fuisse credatur; de-
cidere tamen crebro non erit dubium." The fall of a moderate-sized
stone, which is pi'eserved in the Gymnasium at Abydos, is also report-
ed to have been foretold by Anaxagoras. The fall of aerolites in bright
sunshine, and when the Moon's disk was invisible, probably led to the
idea of sun-stones. Moreovev, 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" (fivdpoc dtdTvvpo^). In accord-
ance with these views of Anaxagoras, we find Euripides, in Phaeton,
terming the Sun "a golden mass;" that is to say, a tire-colored, bright-
ly-shining matter, but not leading to the inference that aerolites are
golden suu-stones. (See note to page 115.) Compare Valckenaer,
Diatribe in Eurip. perd. Dram. Reliqnias, 17G7, 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., il/e/'cor.,
lib. i., cap. iv., 2-13, and cap. vii., 9); a solar origin; and. lastly, an
AEROLITES. 123
Email 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 at-
mosphere, 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 bodies re-
maining invisible to us during many years and frequent revo-
lutions. The supposed phenomenon of ascending shooting
stars and fire-balls, which Chladni has unsuccessfully endeav-
ored to explain on the hypothesis of the reflection of strongly
compressed air, appears at first sight as the consequence of
some unknown tangential force propelling bodies from the
earth ; but Bessel has sho^\^l by theoretical deductions, con-
firmed by Feldt's carefully-conducted calculations, that, owing
to the absence of any proofs of the simultaneous occurrence
of the observed disappearances, the assumption of an ascent
of shooting stars was rendered wholly improbable, and inad-
missible as a result of observation. *" 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 separately and in inconsiderable
numbers, that is, sporadically, or in swarms of many thou-
origin in the regions of space, as heavenly bodies which had long re-
mained invisible. Respecting this last opinion, which is that of Diog-
enes of Apollonia, and entirely accords with that of the px'esent 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
aerolites 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., Exerc, p. 531; and
the passages collected by Ukert, in his Geogr. der Griechen nnd Romer,
th. ii., 1, s. 131, note 14.) On the improbability that meteoric masses
are formed from metal-dissolving gases, which, according to Fusiuieri,
may exist in the highest strata of our atmosphere, and, previously dif-
fused 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.
* Bessel, in Schum., Astr. Nachr., 1839, No 380 und 381, s. 222 iind
346. At the conclusion of the Memoir there is a comparison of the
Sun's longitudes with the epochs of the November phenomeuou, from
the period of the first observations in Cumana ia 1799.
124 COS3IOS.
sands. 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 No-
vember 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 con-
stant recurrence.* Notwithstanding the great quantity of
shooting stars and fire-balls of the most various dimensions,
which, according to Kloden, 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 EUicot and myself,! and which, by
* Dr. Thomas Forster {The Pocket Encyclopedia of Natural Phe-
nomena, 1827, p. 17) states that a manuscript is preserved in the libra-
ry of Chi-ist's College, Cambridge,^ written in the tenth century by a
monk, and entitled Ephemerides Rerum Naturalium, in which the nat-
ural phenomena for each day of the year are inscribed, as, for instance,
the first flowering of plants, the arrival of birds, &c. ; the 10th of Au-
gust is distinguished by the word " meteorodes." It was this indica-
tion, 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. Mathim., Serie III.,
t. i., 1837, p. 433.)
+ Humb., Rel. Hist., t. i., p. 519-527. Ellicot, in the Transaction*
of the American Society, 1804, vol. vi., p. 29. Arago makes the follow-
ing 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
a [No such manuscript is at present known to exist in the Ubrary of that college.
For this information I am indebted to the inquiries of Mr. Cory, of Pembroke Col-
lege, the learned editor of Hieroglyphics of Horapollo Nilous, Greek and English,
1840.]— rr.
AEROLITES. 125
a comparison of the facts I had adduced, showed that the
phenomenon had been simultaneously seen in the New Conti-
n«it, from the equator to New Herrnhut in Greenland (64^
14' north latitude), and between 46° and 82° longitude.
The identity of the epochs was recognized with astonishment.
The stream, which had been seen from Jamaica to Boston
(40° 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.
Muschenbroek,* 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. We shall, no doubt, in time, discover other pe-
riodically appearing streams,! probably about the 22d to the
ecliptic at about the point which our Eai-th annually occupies between
the 11th and 13th of November. It is a new planetary world begin-
ning to be revealed to us." (Annuaire, 1836, p. 296.)
* 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, after the earhest observations of
Brandes (Benzenberg, ilber Sternschnuppen, s. 240-244) ; the August
observations of Thomas Forster, iu Quetelet, op. cit., p. 438-453 ; those
of Adolph Erman, Boguslawski, and Kreil, in Sebum., Jahrb., 1838, s.
317-330. Regarding the point of origin in Pei'seus, on the 10th of Au-
gust, 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 appear to have been retrograde ; see Arago, in Comptes
Rendus, 1837, t. ii., p. 183.
t On the 25th of April, 1095, " innumerable eyes in France saw stars
faUiug from heaven as thickly as hail" {rit grando, nisi lucerent, pro den-
sitate putaretur ; Baldr., p. 88), and this occurrence was regarded by
the Council of Clermont as indicative of the great movement in Chris-
tendom. (Wilken, Gesch. der Kreuzzuge, bd. i., s. 75.) On the 25th
of April, 1800, a great fall of stars was observed in Virginia and Mas
sachusetts ; it v/as " a fire of rockets that lasted two hours." Arago
was the first to call attention to this " trainee d'asteroTdes," as a recur-
ring phenomenon. {Annuaire, 1836, p. 297.) The falls of aerolites in
the beginning of the mouth of December are also deserving of notice.
In reference to their- periodic recurrence as a meteoric stj-eam, we may
mention the eai'ly observation of Brandes on the night of the 6th and
7th of December, 1798 (when he counted 2000 falling stars), and very
126 COSMOS.
25tli of April, between the Gth and 12th of December-, and,
to judge by the number of true falls of aerolites enumerated
by Capocci, also between the 27th and 29th of November, or
about the 1 7th of July.
Although the phenomena hitherto observed appear to have
been independent of the distance from the pole, the tempera-
ture 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
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 re-
markable than at Richmond, near London. I have mentioned
in another work the singular fact observed by Admiral Wran-
gel, and frequently confirmed to me by himself,*' that when he
probably the enormous fall of aSrolites that occurred at the Rio Assu,
near the village of Macao, in the !6razils, on the 11th of December, 1836.
(Brandes, Unterhalt. fur Freunde der Physik, 1825, heft i., s. 65, and
Comptes Rendus, t. v., p. 211.) Capocci, in the interval betvreen 1809
and 1839, a space of thirty years, has discovered twelve authenticated
cases of aerolites occurring betw^een 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 vv^ith the months of Jan-
uary and February, and probably also with March, no periodic streams
of falling stars or aerolites 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 Februaiy, 1797. From the phenomena hith-
erto 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 differ-
ences existing between isolated comets and rings filled w^ith asteroids,
to regard the frequency of these meteoric streams with less astonish-
ment than the first consideration of the phenomenon would be likely
to excite.
* Ferd. v. Wrangle, Reise Idngs der Nordkuste 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 infonmed 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
AERULITKS. 1 il
was on the Siberian coast of the Polar Sea, he observed, during
an Aurora BoreaHs, certain portions of the vault of heaven,
which were not illuminated, light up and continue luminous
whenever a shooting star passed over them.
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. Accord-
ing 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 smaller plan-
ets 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 be-
comes visible, or the retardatio7is of the phenomena of which
I hav^e already spoken, indicate a regular precession or oscilla.-
tion 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
rinsf 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 im-
mense 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 rev-
olution round the Sun, requires three days to traverse an ex-
tent 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 sel-
dom 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.
the 11th and 12tli of November, 1799, a similar fiery mauif'estalioii 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
6j)ace of an hour enveloped in falling slars, so tlmt the inhabitants en-
deavored to appease heaven by religious processions. {Eelat. Hist.,
I' \., ciiap. i\'., p .307 ; chap, x., j). .520 and 527.)
128 COSMOS.
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 shoiver vi^as seen in England
in the year 1837, w^hile 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 tht-
time through a part of the meteoric ring proportionally lesi-
densely studded with bodies." If the hypothesis of a regular
progression or oscillation of the nodes should acquire greatei
weight, special interest will be attached to the investigation
0^ 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 Tyrtseus, or the sec-
ond 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, thosQ 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 epochsf indicated. 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 Ckronicon Ecclesice Pragensis), be
identical with our November phenomenon, although the oc-
currence in the fourteenth century was seen in broad day-
light, we find by the precession in 477 years that this system
of meteors, or, rather, its common center of gravity, must de-
* From a letter to myself, dated Jan. 24th, 1838. The enormous
swarm of falling stax's in November, 1799, was almost exclusively seen
in America, where it was witnessed from New Herruhut in Greenland
to the equator. The sw^ai'ms of 1831 and 1832 were visible only iu
Europe, and those of 1833 and 1834 only in the United States of North
America.
t Lettre de M. Edouard Biot a M. Quetelet, sur les anciennes appari-
tions d'Etoiles Filantes en Chine, in the Bull, de V Acadimie de Brux'
elles, 1843, t. x., No. 7, p. 8. On the notice from the Ckronicon Ec-
clesice Pragensis, see the younger Boguslawski, in Poggend., Annalert,
bd. xlviii., s. 612.
AEROLITES. ^ 129
Bcribe 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 be-
tween the asteroid groups, or, according to Poisson, to the ac-
tion of the larger planets* on the form and position of thii
annulus.
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 dark small cloud, are accompanied by much
noise, and although heated, are not in an actual state of in-
candescence. They undeniably exhibit a great degree of gen-
eral 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 ob-
served 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 excep-
tions regarding individual points. What differences, for in-
stance, do we not find between the malleable masses of iron
of Hradschina in the district of Agram, those from the shores
of the Sisim in the government of Jeniseisk, rendered so cele-
brated by Pallas, or those which I brought from Mexico,t all
of which contain 96 per cent, of iron, from the aerolites of
Siena, in which the iron scarcely amounts to 2 per cent., or
the earthy aerolite of Alais (in the Department du Gard),
which broke up in water, or, lastly, from those of Jonzac and
Juvenas, which contained no metallic iron, but presented a
* " 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 im«
possible at others." — Poisson, Recherches sur la Probability des Juge-
vients, p. 306, 307.
t Humboldt, Essai Politique sur la Nmiv. Espagne (2de edit.), t. iii.
p. 310.
F 2
130 COSMOS.
mixture of oryctognostically distinct crystalline components !
These differences have led mineralogists to separate these cos-
mical masses into two classes, namely, those containing nick
elliferous meteoric iron, and those consisting of fine or coarse-
ly-granular meteoric dust. The crust or rind of aerolites is
peculiarly characteristic of these bodies, being only a few
tenths of a line in thickness, often glossy and pitch-like, and
occasionally veined.* There is only one instance on record,
as far as I am aware (the aerolite of Chantonnay, in La Ven-
dee), 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 granite blockst which I brought from the cata-
racts of the Orinoco, and which are also associated with
many other cataracts, as, for instance, those of the Nile and
of the Congo River. The greatest heat employed in our
porcelain ovens would be insufficient to produce any thing
similar to the crust of meteoric stones, whose interior re-
mains 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, sul-
phur, 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 aerolites, 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
* The peculiar color of their crust was observed even as' early as ia
the time of Pliny (ii., 56 and 58): "colore adusto." The phrase "lateri-
bus pluisse" seems also to refer to the burned outer surface of aerolites.
t Humb., Rel. Hist., t. ii., chap, xx., p. 299-302.
AEROLITES. 131
found incorporated with aerolites, imparts to them a pecul-
iar, but not, consequently, a s,elenic character ; for in other
regions of space, and in other cosmical hodies besides our Moon,
water may be wholly absent, and processes of oxydation of
rare occurrence.
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 Sterli
tamak, west of the Uralian Mountains, which are said to have
constituted the interior of hailstones,* must both be classed
among the mythical fables of raeteorolog}^ Some few aero-
lites, 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 I'Ardeche, which re-
sembled dolorite), are the only ones, as Gustav Rose has
remarked, which have a more familiar aspect. These bodies
contain, 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 re-
placed by oxyd of tin.:t As meteoric olivine, like our basalt,
contains from 47b to 49 per cent, of magnesia, constituting,
according to Berzelius, almost the half of the earthy compo-
nents of meteoric stones, we can not be surprised at the great
quantity of silicate of magnesia found in these cosmical bodies.
If the aerolite of Juvenas contain separable crystals of augite
and labradorite, the numerical relation of the constituents
* Gustav Rose, Reise nach dem Ural, bd. ii., s. 202.
t Gustav Rose, in Poggend., Ann., 1825, bd. iv., s. 173-192. Ram-
melsberg, Erstes Suppl. zum chem. Handworterbuche der Mineralogie,
1843, s. 102. "It is," says the clear-minded obsex-ver Olbei's, '"a re-
markable but hitherto uni-egarded fact, that while shells are found in
secondary and tertiaiy formations, no fossil meteoric stones have as yet
been discovered. May we conclude from this circumstance that pre-
vious to the present and last modification of the earth's surface no me-
teoric 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 West-
ern Carpathians (the mountain chain of Magura, at Szlanicz), both of
which are remarkably like meteoric stones. Compare Erman. Arckiv
fur wissenschaftliche Kundevon Russland, hd. i., s. 315, and Haidhiger,
Bericht uher Szlaniczer Schurfe in Ungarn.
X Berzelins, Jahresber., bd. xv., s. 217 und 231. Rammelsberg,
Handtcdrterb., abth. ii., s. 2.5-28.
132 COSMOS.
render it at least probable tbat the meteoric masses of Cha-
teau-Ren ard may be a compound of diorite, consisting of horn-
blende and albite, and those of Blansko and Chantonnay com-
pounds of hornblende and labradorite. The proofs of the tel-
luric and atmospheric origin of aerolites, which it is attempt-
ed to base upon the oryctognostic analogies presented by these
bodies, do not appear to me to possess any great weight.
Recallins: to mind the remarkable interview between New-
ton and Conduit at Kensington,* I would ask why the ele-
mentary substances that compose one group of cosmical bodies,
or one planetary system, may not, in a great measure, be iden-
tical ? 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 ofi^ from the once far more expanded solar at-
mosphere, and been formed from vaporous rings 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 Avhich 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 at-
traction, blend together under definite relations of mixture,
composing the white glittering 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 ar-
bitrary views devoid of the support of inductive reasoning.
Remarkable obscurations of the sun's disk, during whicli
the stars have been seen at mid-day (as, for instance, in the
obscuration of 1547, which continued for three days, and oc-
curred about^ the time of the eventful battle of Miihlberg),
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
* " 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 vari-
ously concocted." — Turner, Collections for the History of Grantham^
eontainhig authentic Memoirs of Sir Isaac Newton, p. 172.
AEROLITES. 133
hours, were supposed by Chiadni and Schnurrer to be occa
sioned by the passage of meteoric masses before the sun's disk.
Since the period that streams of meteoric shootmg stars were
first considered with reference to the direction of their orbit
as a closed ring, the epochs of these mysterious celestial phe-
nomena have been observed to present a remarkable connec
tion with the regular recurrence of swarms of shooting stars
Adolph Erman has evinced great acuteness of mind in his ac-
curate investiofation of the facts hitherto observed on this sub-
ject, and his researches have enabled him to discover the con-
nection 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."^
The Greek natural philosophers, who were but little dis
posed to pursue observations, but evinced inexhaustible fer
tility of imagination in giving the most various interpretation
of half-perceived facts, have, however, left some hypotheses
reofardinor 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,t " are, according to
* Adolph Erman, in Poggend., Annalen, 1839, bd. xlviii., s. 582-
601. Biot had preNaously thrown doubt regarding the probability of
the November stream reappearing in the beginning of May (Comptes
Rendns, 1836, t. ii., p. 670). Madler has examined the mean depres-
sion of temperature on the three ill-named days of May by Berlin ob-
servations for eighty-six years ( Verhandl. des Vereins zur Befurd. des
Gartenbaues, 183"4, s. 377), and found a retrogression of temperature
amounting to 20-2 Fahr. from the 11th to the 13th of May, a period at
wliich 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 i*i the southern hemisphere. (Comp. Bull, de VAcad.
Imp. de Si. Petershourg, 1843, t. i.. No. 4.)
t Plut., Vitce par. in Lysandro, cap. 22. The statement of Dama-
cho9 (Daimachos), that for seventy days continuously there was a fiery
cloud seen in the sky, emitting sparks like falling stars, and which then,
sinkii^g nearer to the earth, let fall the stone of iEgos Potamos, " which,
however, was only a small pai't of it," is extremely improbable, since
the direction and velocity of the fire-cloud would in that case of neces-
sity 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 alto-
gether certain whether Daimachos, the writer, -Kepi evaef'ELag, was the
134 coSiMos.
k
f
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 conse-
quence of a certain intermission in the rotatory force, and by
the impulse of some irregular movement, 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." Diogenes of Apollonia^ expresses himself still more
explicitly. 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
to the earth and are extinguished, as the stony star which fell
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 con-
verted into stars." In the Ionian school, therefore, according
to the testimony transmitted to us in the views of Diogenes
of Apollonia, aerolites 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,t
same person as Daimachos of Platjea, who was sent by Seleucus to
India to the sou of Androcottos, and who was 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 aerolites
occurred in Thrace, and whose authenticity is also doubted by Plutarch.
■* Stob., ed. Heeren, i., 25, p. 508 ; Plut., de plac. Philos., ii., 13.
t The remarkable passage in Plut., deplac. Philos., ii., 13, runs thus:
'' Anaxagoras teaches that the surrounding ether is a fiery substance,
which, by the power of its rotation, tears rocks from the earth, inflames
tliem, and converts them into stars." Applying an ancient fable to il-
lustrate a physical dogma, the Clazomenian appears to have ascribed
the fall of the Nemtean Lion to the Peloponnesus from the Moon to
such a rotatory or centrifugal force, (^lian., xii., 7; Pint., de 'Facie
in Orbe Lunce, c. 24; Schol. ex Cod. Paris., in ApoU. 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 niiimal from the
Moon! According to an acute remark of Bockh, the ancient mythol-
ogy of the Nerasean lunar lion has an astronomical origin, tind is sym-
AEROLITES. 135
foiming all things around it in the same manner as we, ac-
cording to our present views, suppose the planets of our sys-
tem to have originated in the expanded atmosphere of anoth-
er central body, the Suri. These views must not, therefore,
be confounded with what is commonly termed the telluric or
atmospheric origin of meteoric stones, nor yet with the singu-
lar opinion of Aristotle, which supposed the enorn:v)us mass
of iEgos Potamos to have been raised by a hurricane. That
arrogant spirit of incredulity, which rejects facts without at-
tempting to investigate them, is in some cases almost more
injurious than an unquestioning credulity. Both are alike
detrimental to the force of investigfation. Notwithstandinsr
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 irre-
proachable eye-witnesses — notwithstanding the important part
enacted by the Baetylia in the meteor- worship of the ancients
— notwithstanding the fact of the companions of Cortez hav-
ing seen an aerolite at Cholula which had fallen on the neigh-
boring 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 re-
mained almost wholly unheeded, and its intimate connection
with other planetary systems unknown, until attention was
drawn to the subject by Chladni, who had already gained im-
mortal 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 an-
imated 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,
bolically connected in chronology with the cycle of intercalation of the
lunar year, with the moon- worship at Nemiea, and the games by which
it was acc(impanied.
136 COSMOS.
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 sat-
ellites, or that of Ceres, with the immense volume of the Sun,
all relations of magnitude vanish from our minds. The ex-
tinction 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 vi-
cinity 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 uni-
verse 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. An-
other 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 lumin-
ous or calorific vibrations, or in obedience to the laws of mu-
tual 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 pos-
sible 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 find-
ing that we may examine, weigh, and analyze bodies that ap-
* The following remarkable passage on the radiation of heat from
the fixed stars, and on their low combustion arid vitality — one of Kep-
ler's many aspirations — occurs in the Paralipom. in Vitell. Astron. para
Optica, 1604, Propos. xxxii., p. 25 : " Lucis 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 meusura, uterquo simul percipi et
judicari possit. De cincindularum lucula tenuissima negare non potes,
quin cum calore sit. Vivunt enim et moventur, hoc autem non sine
calefactione perficitur. Sic neque putrescentium lignorum lux sno ca«
lore destituitur ; nam ipsa puetredo quidam lentus ignis est. Inest et
stirpibus suus calor." (Compare Kepler, Epit. Astron. Copernicance,
1618, t. i., lib. i., p. 35.)
ZODIACAL LIGHT. 137
pertain 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 power-
ful natural force.
Although the asteroid-swarms, on which we have been led,
from special predilection, to dwell somewhat at length, ap-
proximate 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, illu-
mines a part of the uniform length of tropical nights. I have
seen it shine with 9.n intensity of hglit equal to the milky way
in Sagittarius, and that not only in the rare and dry atmos-
phere of the summits of the Andes, at an elevation of from
thirteen to fifteen thousand feet, but even on the boundless
grassy plains, the llanos 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 aerial spec-
tacle 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 10^ a,nd 14° 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 zodi-
138 COSMOS.
acal light, although the night was already perlectly dark. An
hour after sunset it was seen in great brilUancy between Alde-
baran and the Pleiades ; and on the 18th of March it attained
an altitude of 39^ 5'. 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 ap-
pears 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 phe-
nomenon should have failed to attract the attention of physi-
cists and astronomers until the middle of the seventeenth cen-
tury, or how it could have escaped the observation of the Ara-
bian natural philosophers in ancient Bactria, on the Euphra-
tes, and in the south of Spain. Almost equal surprise is ex-
cited by th^ tardiness of observation of the nebulous spots in
Andromeda and Orion, first described by Simon Marius and
Huygens. The earliest explicit description of the zodiacal
fight occurs in Childrey's Britannia Baconica* in the year
* " There is another thing which I recommend to the observation
of mathematical men, which is, that in February, and for a fittle before
and a Httle 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 towai-d the Pleiades, and seeming almost to touch them. It is so
observed any clear night, but it is best iliac 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
S)f 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 Baco-
nica, 1661, p. 183.) This is the first view and a simple description of
the phenomenon. (Cassini, Dicouverte de la Lumiere Cileste qui pa-
roit dans le Zodiaque, in the M&m. de VAcad., t. viii., 1730, p. 276.
Mairan, TraiU Phys. de V Aurore Boriale, 1754, p. 16.) In this remark-
able work by Childrey there are to be found (p. 9 1) very clear accounts
of the epochs of maxima and minima diurnal and annual temperatures.
I
zoiJiATAL i.i(;in'. 139
IGCl. Tlie first observation of the phenomenon may have
been made two or three years prior to this period ; but, not-
withstanding, the merit oi" 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
whii^h he saw at Bologna in 1668, and wliich was observed
at the same time in Persia by the celebrated traveler Char-
din (the court astrologers of Ispahan called this light, which
had never before been observed, nijzek, a small lance), was
not the zodiacal light, as has often been asserted,* but the
and of the retardation of the extremes of the effects in meteorological
processes. It is, howevei", to be regretted that our Baconian-philosophy-
loving author, who was Lord Henry Somerset's chaplain, lell into the
same error as Bernardin de St. Pierre, and regarded the Earth as elon-
gated at the poles (see p. 148). At the first, he believes that the Earth
was spherical, but supposes tliat the uninterrupted and inci'easing addi-
tion of layers of-ice at both poles has changed its figure ; and that, as the
ice is formed from water, the quantify of that hquid is every where
diminishing.
* Dominicus Cassini {Man. de VAcad., t. viii., 1730, p. 188), and
Mairaii {Aurore Bor., p. 16), have even maintained that the phenome-
non observed in Persia in 16G8 was the zodiacal light. Delambre
{Hist, de V Astron. Moderne, t. ii., p. 742), in very decided terms, ascribes
the discovery of this light to the celebrated traveler Chardin ; but in the
C our 07171 ement de Soliman, and in several passages of the narrative of his
travels (ed. de Langles, t. iv., p. 326; t. x., p. 97), he only applies the
term niazouk (nyzek), or "petite lance," to " tiie great and famous
comet which appeared over neai'ly the whole world in 1668, and whose
head was so hidden in the w^est that it could not be perceived in the
horizon of Ispahan" {Atlas du Voyage de Chardin, Tab. iv. ; froin the
observations at Schiraz). The head or nucleus of the comet was, how-
ever, visible in the Brazils and in India (Pingie, Cometog7-., t. ii., p. 22).
Regardhig the conjectured identity of the last great comet of March,
1843, with this, which Cassini mistook for the zodiacal light, see Schuin.,
Astr. Nachr., 1843, No. 476 and 480. In Persian, the term "nizehi
alteschin" (fiery spears or lances) is also applied to the rays of the ris-
ing or setting sun, in the same way as " nayazik," according to Frey-
tag's Arabic Lexicon, signifies " Stella) cadentes." The comparison of
comets to lances and swords was, however, in the Middle Ages, ve;y
common in all languages. The great comet of 1500, which was visible
from April to June^ was always termed by the Italian writers of tliat
time il Signor Astone (see my Exa77ien Critique de V Hist, de la Geo-
graphic, 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, ap-.
pear 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 I'ays, which, falling on different parts of
the planetary orbs, strike the eye laterally by extraordinaiy 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. As
140 COSMOS.
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. We may conjecture, with much probability, that the
remarkable light on the elevated plains of Mexico, seen for
forty nights consecutively in 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 Az-
tec MS., the Codex Telleriano-Reinensis* preserved in the
Royal Library at Paris.
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 conse-
quently can not be diffused beyond g^ths of Mercury's helio-
centric distance. These same laws teach us that the altitude
of the extreme boundaries of the atmosphere of a cosmical
tron. Copernicance, 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 6oKovg vocant" (Plin., ii., 2G and 27) had reference to the tongue-
shaped rising zodiacal light, as Cassini (p. 231, art. xxxi.) and Mairan
(p. 15) have maintained. Everywhere among the ancients the trabes
are associated with the bolides (ardores et faces) and other fiery mete-
ors, and even with long-barbed comets. ( Regarding doKog, doKiag,
doKLTijg, see Schafer, Schol. Par. ad Apoll. Rhod., 1813, t. ii., p. 206;
Pseudo-Aristot., de Mimdo, 2, 9 ; Comment. Alex. Joh. Philop. et Olymp.
in Aristot. Meteor., lib. i., cap. vii., 3, p. 195, Ideler; Seneca, Nat.
Quf£st., i., 1.)
* Humboldt, Monumens des Peuples Indighies de V Amirique, t. ii..
p. 301. The rare manuscnpt which belonged to the Archbishop of
Rheims, Le Tellier, contains various kinds of extracts from an Azt^
ritual, an astrological calendar, and historical annals, extending from
1197 to 1549, and embx'aciug 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 manusci-ipt 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 vol-
canic eruptions of Popocatepetl, which lies very near, in tlie southeast-
ern direction. (Prescott, History of the Conquest of Mexico, vol. i., p.
284.) Later commentators have confounded this phenomenon, which
Montezuma regarded as a warning of his misfortunes, with the " estrella
que huraeava" (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" (Cit-
laltepetl, the volcano of Orizaba), see my Monumens, t. ii., p. 303.
ZODIACAL LIGHT. 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 sateUite would rotate round
the central body simultaneously with the diurnal revolution
of the latter.* This Umitation 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, there-
fore, 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.t
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. As
* Laplace, Expos, du Syst. du Monde, p. 270 ; M6canique C6leste,
t. ii., p. 169 and 171; Schubert, Astr.,hd. iii., § 206.
t Arago, in tlie Annuaire, 1842, p. 408. Compare Sir John Her-
schel's considerations on the volume and faintness of li^ht of planetary
nebulae, in Mary Somerville's Connection of the Physical Sciences, 1835,
p. 108. The opinion that the Sun is a nebulous star, whose atmos-
phere presents the phenomenon of zodiacal liglit, did not originate with
Dominicus Cassini, but was first promulgated by Mairan in 1730 ( Traits
de VAurore Bor., p. 47 and 263 ; Arago, in the Annuaire, 1842, p.
412). It is a renewal of Kepler's views.
X Dominicus 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 ex-
tent), 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." {Mim. de I' Acad., t. viii., 1730, p. 218,
and Biot, in the Comptes Rendus, 1836, t. iii., p. 666.) Cassini be-
lieved 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 01
bers 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.
142 COSMOS.
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 appear 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.
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 remark-
able), which occurred at the time of the new moon at mid-
night in 1743, the phosphorescence was so intense that ob-
jects 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 llanos, I enjoy-
ed ample opportunities of carefully examining this phenome-
non. 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.f 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, de-
tect 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 con-
densation 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 man-
* Sir John Herschel, Astron., ^ 487.
t Arago, in the Annuaire, 1832, p. 246. Several physical facts ap
pear to indicate that, in a mechanical separation of matter into its small-
est 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 miiTor have not hitherto
given any positive evidence of the presence of radiant heat in the zo-
diacal light. (Lettre de M. Matthiessen a M. Arago, in the Comptes
Rendus, t. xvi., 1843, Avril, p. 687.)
ZODIACAL LIGHT. 143
ner ? 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 sec-
onds through the tail of a comet, v/hich appeared during the
continuance of the pulsations of light to be lengthened by sev-
eral degrees, and then again contracted.* As, however, the
separate particles of a comet's tail, measuring millions of miles,
* "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 trop-
ics, is of the greater 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
I'otated ; but I assumed (contrary to Poisson's opinion, w^hich 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 suiTOunding 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 other years
it is scarcely perceptible. I think that I find the first trace of an allu-
sion to the zodiacal light in a letter from Rothmann toTycho, in which
he mentions that in spring he has observed the twilight did not close
until the sun was 24*^ below the horizon. Rothmann must certainly
have confounded the disappeai'ance 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 vainalions 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
most strikingly seen in the tails of large comets. We often observe,
especially in tlie clearest weather, that these tails exhibit pulsations,
commencing from the head, as being the lowest part, and vibrating in
one or two seconds tln-ough 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 Schroter and Chladni, do
not actnally occur in the tails of the comets, but are produced by our at-
mosphere, is obvious when we recollect that the individual parts of
those tails (which ai'e many millions of miles in length) lie at very dif-
ferent 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 coin-
cide with the Sun's place below the horizon." (From a letter wr'tten
by Dr. Olbers to myself, and dated Bremen, March 26th. 1833.)
144 COSMOS.
are verj' unequally distant from the 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 per-
ceive any actual changes in. a cosmical body of such vast ex-
tent. These considerations in no way exclude the reality of
the change^ 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, accord-
ing to the most recent and acute researches on the crepuscular
theory, and of the height of the atmosphere.^ The phenom-
ena 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 solar
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 re-
volves round the Sun in the vicinity of the Earth, and for
which, owing to its position, we may retain the name of zo-
diacal 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 atmos-
phere from the external regions of universal space are alone
arrested in the course of their planetary revolution, and re-
tained within the sphere of a larger planet. In the solar sys-
tem, whose boundaries determine the attractive force of the
central body, comets are made to revolve in their elliptical
* Biot, TraiU d'Asiron. Physique, 3eme ed., 1841, t. i., p. 171, 238.
and 312.
TRANSLATORY MOTION OF THE SOLAR SYSTEM. 145
orbits at a distance 44 times greater than that of Uranus ;
nay, 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 mill-
ions of miles. Central forces, therefore, at once constitute and
maintain the system.
Our Sun may be considere'l as at rest when compared to all
the large and small, dense and almost vaporous cosmical bodies
that appertain to and revolve around it ; but it actually ro-
tates round the common center of gravity of the whole sys-
tem, which occasionally falls within itself, that is to say, re-
mains within the material circumference of the Sun, what-
ever changes may be assumed by the positions of the planets.
A very different phenomenon is that presented by the trans-
latory 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 6 1 Cygni, is not less
m one day than 3,336,000 geographical miles. This change
of the entire solar system would remain unknown to us, if the
admirable exactness of our astronomical instruments of meas-
urement, and the advancement recently made in the art of
observinff, did not cause our advance toward remote stars to
be perceptible, like an approximation to the objects of a dis-
tant shore in apparent motion. The proper motion of the star
6 1 Cygni, for instance, is so considerable, that it has amount-
ed 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 equi-
noxes, 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
* Bessel, in Schura., Jalirh.fur 1839, s. 51; probably four millions
of miles daily, iu a relative velocity of at the least 3,336,000 miles, or
more than double the velocity of revolution of the Earth in her orbit
round the Sun.
Vol. I.— G
1 46 COd.MOS.
of the annual motion of the fixed stars due to the translatiou
of thy whole solar system in universal space, and to the true
proper motion of the stars. The difficult problem of numer-
ically separating these two elements, the true and the appar-
ent motion, has been effected by the careful study of the di-
rection 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, con-
firmed by the calculus of probabilities, is, that our solar sys-
tem and the stars both change their places in space. Accord-
ing to the admirable researches of Argelander at Abo, who
has extended and more perfectly developed the work begun by
William Herschel and Prevost, the Sun moves in the direc-
tion 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 257° 49'-7 R.A., and
28° 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 alone owing to the solar system.*
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 cer-
tainly inclines the intellectual activity, no less than the imag-
ination 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
* Regarding the motion of the solar system, according to Bradley,
Tobias Mayer, Lambert, Lalaude, and William Herschel, see Arago,iu
the Anmiaire, 1842, p. 388-399; Argelander, in Schum., Asfron. Nachr.,
No. 363, 364, 398, and in the treatise Voti der eigcnen Bewegnng des
Soymensy stems (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 V Acad, de St. Petersh., 1842, t. x.,
No. 9, p. 137-139. The last-named astronomer has found, by a more
recent combination, 261^ 23' R.A.4-37° 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 259"
3' R.A. 4- 34° 36' Decl.
TRANSLATORY MOTION. 14T
the concatenation of causes if there were not one primordiai
immovable motor."*
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 con-
stantly going on in the regions of space, afford us incontro-
vertible 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 conjec-
ture, 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 re-
volving round a center of gravity lying ivitliout their system
(2800 such systems having been discovered up to 1837), but
rather the extension of our knowledge regarding the funda-
mental forces of the whole material world, and the proofs we
have obtained of the universal empire of the laws of attrac-
tion, 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 7\ of Corona, and in others to sev-
eral 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 ^ of Cancer has com-
pleted more than one entire revolution. By a skillful com-
bination of the altered distances and angles of position,! the
elements of these orbits may be found, conclusions drawn re-
garding the absolute distance of the double stars from the
Earth, and comparisons made between their mass and that
of the Sun, Whether, however, here and in our solar sys-
tem, quantity of matter is the only standard of the amount
of attractive force, or whether specific forces of attraction pro-
portionate to the mass may not at the same time come into
operation, as Bessel was the first to conjecture, are questions
* Aristot., de Caelo, iii., 2, p. 301, Bekker ; Phys., viii., 5, p. 256.
t Savary, in the Connaissance des Terns, 1830, p. 56 and 163. Encke,
Berl. Jahrb.. 1832, s. 253, &c. Arago, in the Annuaire, 1834, p. 260
295. John Herschel, in the Memoirs of the Astronom. Soc, vol. v., p. 17 1
148 COSMOS.
whose practical solution must be left to future ages.* When
we compare our Sun with the other fixed stars, that is, with oth
er 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 constella-
tion Centaur, almost 31,300 from 61 Cygni, and 41,600 from
Vega in the constellation Lyra. The comparison of the vol-
ume of the Sun with that of the fixed stars of the first mag-
nitude is dependent upon the apparent diameter of the latter
bodies — an extremely uncertain optical element. If even we
assume, with Herschel, that the apparent diameter of Arctu-
rus 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.f The distance of the star 61 Cygni, made known
by Bessel, has led approximately to a knowledge of the quan-
tity of matter contained in this body as a double star. Not-
withstanding 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 and the major axis of this star, it has been conjec-
tured with much probability by the great Konigsberg astron-
omer,t " that the mass of this double star can not be very con-
siderably larger or smaller than half of the mass of the Sun."
This result is from actual measurement. The analogies de-
duced 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
* Bessel, Untersuchung. des Theils der planetaHschen Storungen,
welcke aus der Betcegumg der Sonne entsieken (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),
8. 2-6. The question has been raised by John Tobias Mayer, in Com-
ment. Soc. Reg. Gotting., 1804-1808, vol. xvi., p. 31-68.
t Fkilos. 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.
X Bessel, in Schum., Jahrb., 1839, s. 53.
TRANSLATORY MOTION. l49
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.* We are, however, far from having arrived at general
results regarding this subject. Our Sun, according to Arge-
lander, 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 nebulse, 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 nebulse, 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 suc-
cessively be indicated by the stars (3 and a Cephei, and 6 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 inter-
mission 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 movinor in throngfed
groups in difierent directions ; nebulse w^andering 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 heaven, even as on the Earth's surface, where we
see it unfolded in the germ, the leaf, and the blossom, the or
ganisms of the vegetable world. The celebrated Spanish bot
anist Cavanilles was the first who entertained the idea of
" seeing grass grow," and he directed the horizontal microme-
ter threads of a powerfully magnifying glass at one time to
* Madler, Astron., s. 476; also in Schum.. Jahrb., 1839, s. 9.5.
150 COSMOS.
the apex of the shoot of a bambusa, and at another on the
rapidly-growing stem of an American aloe [Agave Americmia),
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 Miiky 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.* The two
brilliant nodes in which the branches of the zone unite, in the
region of Cepheus and Cassiopeia, and in the vicinity of Scor-
pio and Sagittarius, appear to exercise a powerful attraction
on the contiguous stars ; in the most brilliant part, however,
between /3 and y Cj^gni, one half of the 330,000 stars that
have been discovered in a breadth of 5^ 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.f The num-
ber of telescopic stars in the Milky Way uninterrupted by any
nebulEe 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 per-
ceptive powers of man, is awakened in both extremes of the
universe, in the celestial bodies as in the minutest animal-
cules. $ A cubic inch of the polishing slate of Bilin contains,
according to Ehrenberg, 40,000 millions of the silicious shells
of GalionellsB.
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
* Sir William Herschel, in the Pkilos. Transact, for 1817, Part ii.
p. 328. t Arago, in the Anmiaire, 1842, p. 459.
X Sir JoliQ 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.)
THK MII.lvV WAV. 151
with another Milky Way, composed of nebulai. The Ibrmer
constitutes, according to Sir J ohn Herschel's views, an annu-
lus, 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 op-
posite point, Cassiopeia.* An imperfectly seen nebulous spot,
discovered by Messier in 1774, appeared to present a remark-
able similarity to the form of our starry stratum and the divided
ring of our Milky Way.t The Milky V/ay composed of neb-
ula; does not belong to our starry stratum, but surrounds it at
a great distance without being physically connected with it,
passing ahiiost 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 ag-
glomerate 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 second-
ary 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 wo
generally term the Milky Way, is composed of nebulous stars,
avera^ino- from the tenth to the eleventh degree of magni-
tude,| but appearing, when considered individually, of very
difierent magnitudes, while isolated starry clusters (starry
swarms) almost always exhibit throughout a character of
great uniformity in magnitude and brilliancy.
In whatever part the vault of heaven has been pierced by
powerful and far-penetrating telescopic instruments, stars or
luminous nebulss are every where discoverable, the former, in
* Sir John Herschel, Astronom.., § 624; likewise in his Obsei'vations
■)n Nebulceand Clusters of Stars {Phil. Transact. ^ 1833, Part ii.,p. 479,
fig. 25) : " We have here a brother system, bearing a real physical re
jemblauce and strong analogy of structure to our own."
t Sir William Herschel, in the Phil. Trans, for 1785, Part i., p. 257.
Sir .John Herschel, Astron., $ 61G. (" The nebulous region of the heav-
ens forms a nebulous Milky Way, composed of distinct uebulse, as the
other of stars." The same observation was made in a letter he addressed
to mfi in March. 1829.) t Sir John Herschel, Astron., $ 585.
152 COSMOS.
Bome cases, not exceeding the twentieth or twenty-fourth de
gree of telescopic magnitude. A portion of the nebulous vapoi
would probably be found resolvable into stars by more power
ful optical instruments. As the retina retains a less vivid im-
pression of separate than of infinitely near luminous points,
less strongly marked photometric relations are excited in the
latter case, as Arago has recently shown.* 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 Gi-
bers, should arise, if every point throughout the depths of space
were filled by an infinite series of stars. f The assumption of
such a distribution in space is, however, at variance with ob-
servation, which shows us large starless regions of space, 02:)en-
ings in the heavens, as William Herschel terms them — one,
four degrees in width, in Scorpio, and another in Serpentari-
us. In the vicinity of both, near their margin, we find un-
resolvable nebulae, of which that on the western edge of the
opening in 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 at-
tractive and agglomerative forces of the marginal groups. $
" 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 Scor-
pio 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 [cJiasmata)
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
* Arago, iu the Annuaire, 1842, p. 282-285, 409-411, and 439-442.
t Olbers, on the transparency of celestial space, in Bode's Jalirh.,
1826, s. 110-121.
X " An opening in the heavens," William Hersche],in the Phil. Trans.
for 1785, vol. Ixxv., Part i., p. 256. Le Fran9ais Lalande, in the Con-
naiss. des Terns pour V An. VIII., p. 383. Arago, in the Annuaire,
1842, p. 425.
STARLESS OPENINGS. 153
translucent illuminated ether which lay beyond them.* Der-
ham, and even Huygens, did not appear disinclined to explain
in a similar manner the mild radiance of the nebuleB.f
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 consider-
ation of the varying distances and the boundlessness of space,
which shows the world of phenomena, and that which con-
stitutes its causal reality, to be dependent upon the ])ropaga-
tion 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 meas-
urements of Maclear, Bessel, and Struve, of the parallaxes
and distances of three fixed stars of very unequal magnitudes
{a Centauri, 16 Cygni, and a Lyrse), a ray of light requires
respectively 3, 9^^. 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 r\ in Argo increase in splendor from the
second to the first magnitude 4 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
* Aristot., Meteor., ii., 5, 1. Seneca, Natur. Qucest., i., 14, 2. " Cce-
lum discessisse," in Gic, de Divin., i., 43.
t Arago, in the Annuaire, 1842, p. 429.
X In December, 1837, Sir John Herschel saw the star ;; 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 Jan-
uary, 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 rj Argo.
G2
154 COSMOS.
hour a ray of light traverses over a space of 592 miHions of
miles. While, according to the theogony of Hesiod, the di-
mensions 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. Much, therefore, has vanished long before it
is rendered visible to us — much that we see was once differ-
ently 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 mild-
ly-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 pre-
sents us with the most ancient perceptible evidence of the ex-
istence 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. "f
From the regions of celestial forms, the domain of Uranus,
we will now descend to the more contracted sphere of terres-
trial 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. If we sup-
pose 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 neb-
* " Hence it follows that the rays of hght 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 An-
nuaire, 1842. p. 334, 359, and 382-385.
t From my brother's beautiful sonnet " Freiheitund Gesetz." (Wil-
helm von Humboldt, Gesammelte Werhe, bd. iv., s. 358, No. 25.)
X Otfried MOUer, Prolegomena, s. 373.
TERRESTRIAT. PHENOMENA. 155
ulous rings, the same connection with this contiguous 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 pow-
erfully excite the light of the Sun in the atmosphere and in the
upper strata of our air, that give rise to heat-engendering elec-
tric 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 exclusive-
ly 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 in-
herent 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, exliibited in unequally ex-
panded 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 al-
most uninterrupted shocks by M^hich it has been moved from
below, undergoes, nevertheless, great changes in the course of
centuries in the relations of the elevation of solid portions,
wdien compared with the surface of the liquid parts, and even
in the form of the bottom of the sea. In this manner si-
multaneous 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 un-
known 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 niidst of
exlialations, and the lava becomes incrusted, as it were, by
156 COSMOS.
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 Plutonic forces. Even where no disruption takes
place the crystalline molecules are displaced, combining to
Ibrm 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 alumin-
ous precipitates, agglomerations of finely-pulverized mineral
bodies, covered with layers of the silicious shields of infusoria,
and with transpwted soils containing the bones of fossil ani-
mal 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, contorted, and
upheaved, by mutual compression and volcanic force, leads
the reflective observer, by simple analogies, to draw a com-
parison between the present and an age that has long passed.
It is by a combination of actual phenomena, by an ideal en-
largement 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 founda-
tion of scientific deduction.
It has been acutely remarked, " that, notwithstanding our
continual employment of large telescopes, we are less ac-
quainted 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 ob-
servation and calculation. Their physical character is, how-
ever, hidden in obscurity, for it is only in our own globe that
we can be brought in immediate contact with all the ele-
ments of organic and inorganic creation. The diversity of
the most heterogeneous substances, their admixtures and met-
amorphoses, 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 clas-
sification gradually become the objects of inductive reasoning.
I would here allude to the advantage, of which I have al-
TERRESTRIAL PHENOMENA. 157
ready spoken, possessed by that portion of physical science
whose origin is famihar to us, and is connected with our earth-
ly 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 gen-
eral 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 com-
binations, 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 het-
erogeneous nature of matter, its chemical differences, the reg-
ular farms in which its molecules combine together, whether
in crystals or granules ; its relations to the deflected or de-
composed waves of Hght by which it is penetrated ; to radi-
ating, transmitted, or polarized heat ; and to the brilHant 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 ob-
jects 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 per-
mitted 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 dif-
ference 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 space from 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*
* In speaking of the greatest depths within the Earth reached by hu
man labor, we must recollect that there is a ditference between the (tb-
solute depth (that is to say, the depth below the Earth's surface ut tii;i.
156 COSxMOS.
do not extend beyond a vertical depth of somewhat more than
2000 feet (about one third of a geographical mile) below the
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, 1844, it
was exactly 1993 feet, the absolute depth being 2231 feet. The tern
perature of the water at the bottom was 91° F., which, assuming the
mean temperature o4' the air at 49°-3, gives an augmentation of tem-
perature of 1° for every 54 feet. The absolute depth of the Artesian
well of Grenelle, near Paris, is only 1795 feet. According to the ac-
count of the missionary Imbert, the fire-springs, " Ho-tsing," of the Chi-
nese, which are sunk to obtain [carbureted] hydrogen gas for salt-boil-
ing, far exceed our Artesian springs in depth. In the Chinese province
of Szii-tschuan these fire-springs are very commonly of the depth of
more than 2000 feet; indeed, at Tseu-lieu-tsing (the place of continual
flowj 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 V Association de la Propagation de la Foi, 1829, No. 16, p. 369.)
The relative depth reached at Mount Massi, in Tuscany, south of
Vol terra, amounts, according to Matteuci, to only 1253 feet. The bor-
ing 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 Staifordshire, where men work 725 yards below the surface
of the earth. (Thomas Smith, Miner's Guide, 1836, p. 160.) Unfortu-
nately, 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 Philas. Mag., vol. v.,
1834, p. 446.) That of the Liege coal-mine, V Espirance, at Seraing,
is 1355 feet, according to M. von Dechen, the director ; and the old
mine of Marihaye, near Val-St.-Lambert, in the valley of the Maes,
is, according to M. Gernaert, Ingenieur des Mines, 1233 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 Eselschacht, at Kuttenberg, in Bo-
hemia, a mine which can not now be worked, had the enormous abso-
lute depth of 3778 feet. (Fr. A. Schmidt, Berggesetze der oster Mon.,
abth. i., bd. i., s. xxxii.) Also, at St. Daniel and at Geish, on the Rorer-
biihel, in the Landgericht (or provincial district) of Kitzbiihl, there
were, in the sixteenth century, excavations of 3107 feet. The plans
of the works of the Rorerbtihel are still preserved. (See Joseph von
Sperges. Tyroler Bergwerksgeschichte, s. 121. Compare, also, Hum-
boldt, Gutachten uher Herantreibung des Meissner Stollens in die Frei-
berger Erzrevier, printed in Herder, uber den jetz bcgonnenen Erbstol-
len, 1838, s. cxxiv.) We may presume that the knowledge of the ex-
traordinary depth of the Rorerbiihel 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
terrse portio, quae unquam hominibus spectanda emerget aut eruitur:
cum profundius in ejus viscera, ultra ♦florescentis extremitatis coirupte-
lam. aut propter aquas in magnis fodin tanquam per venas scaturientes
aut propter aeris salubrioris ad vitam o erariorum sustinendani neces-
sarii defectum, aut propter ingentes sumf tus ad tautos labures exant-
landos, multasque difficultates, ad profundi n-es terrte partes peuetrare
TERRESTRIAL PHENOMENA. 150
level of the sea, and consequently only about g^VTr^^^ of the
Earth's radius. The crystalUne masses that have been erupt-
ed 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 ena-
bled to penetrate. We are able to give m numbers the depth
of the shaft where the strata of coal, after penetrating a cer-
tain way, rise again at a distance that admits of being accu-
rately 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
non possumus; adeo ut quadi-ingeutas aut [quod rarissime] quiugeiitas
orgyas iii quibusdam inetiillis desceiidisse, stupeudus omnibus videatur
conatus." — Gulielmi Gilbert!, Colcestreusis, de Magnate Physiologia
nova. Loud., 1600, p. 40.)
Tiie absolute depth of the mines iu the Saxon Erzgebirge, near Frei
bure, ai'e : in the Tharmhofer mines, 1944 feet; in the Honeubirker
mines, 1827 feet ; the i-elative 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^
recent observations to be 1269 feet. The absolute depth of the cele-
brated 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 great-
er than the height of our Brockeu, and only 200 feet less than that of
Vesuvius) with the loftiest structures that the hands of man have erect-
ed (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 great-
est absolute and relative depths of mines and borings. In descending
eastward ft-om Jerusalem toward the Dead Sea, a view presents itself
to the eye, which, according to our pi'esent hypsometrical knowledge
of the surface of our planet, is unrivaled in any country ; as we ap-
proach the open ravine through which the Jordan takes its course, we
tread, with the open sky above us, on rocks which, according to the ba-
rometric measurements of Berton and Russegger, are 1385 feet below the
level of the Mediterranean. (Humboldt, Asie Cenirale, th. ii., p. 323.)
* Basin-shaped curved strata, which dip and reappear at measurable
distances, although their deepest portions are beyond the reach of the
miner, afford sensible evidence of the nature of the earth's ciixst at great
depths below its surface. Testimony of this kind possesses, consequent-
ly, a great geognostic interest. I am indebted to that excellent geog-
160 COSMOS.
Df the sea, and that the calcareous and the curved strata of
the Devonian basin penetrate twice that depth. If w^e com-
pare these subterranean basins with the summits ot" mountains
that have hitherto been considered as the most elevated por-
tions of the raised crust of the Earth, we obtain a distance of
37,000 feet (about seven miles), that is, about the j-jjth 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 gener-
al elevation of the upper surface of the earth were equal to
the height of the Dhawalagiri 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 regard-
ing 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 in-
nosist, 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 ab-
solute 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 w^hich are presented by the
coal strata of Saar-Revier (SaarbiTJcken). I have found, after repeated
examinations, that the lowest coal stratum which is known in the neigh-
borhood of Duttweiler, near Bettingen, northeast of Saarlouis, must de-
scend 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 De-
vonian strata. This coal-field is therefore sunk as far below the sur-
face of the sea as Chimborazo is elevated above it — at a depth at which
the Earth's temperature must be as high as 435° F. Hence, from tlie
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 radiu.s.
GEOGRAPHICAL DISTRIBUTION. 161
crease of density from the upper surface to tfcfi 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 eruptions, and even in producing
alterations in the level of the sea.* Large plains and vari-
ously indented continents are raised or sunk, lands are sep
arated fi:om 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 fre-
quently changed. Plains have undergone oscillatory move-
ments, being alternately elevated and depressed. After the
elevation of continents, mountain chains were raised upon long
fissures, mostly parallel, and, in that case, probably cotem-
poraneous ; 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 erup-
tions 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 Himalaya to the regions of perpetual snow, have occa-
sioned new compositions and new textures in the rocky masses,
and have altered the strata which had been previously de-
posited from fluids impregnated with organic substances. We
here trace the series of formations, divided and superposed ac-
cording to their age, and depending upon the changes of con-
figuration 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 in-
timate connection and reciprocal action with the encircling
* [See Daubeney On Volcanoes, 2d edit., 1848, p. 539, &c., on the so-
called mui volcanoes, and the reasons advanced in favor of adopting the
term "salses" to designate these phenomena.] — Tr.
162 uosmorj.
sea, in which organic life is almost entirely limited to the ani-
mal world. The liquid element is again covered by the at-
mosphere, an aerial ocean in which the mountain chains and
high plains of the dry land rise like shoals, occasioning a va-
riety 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 de-
clivities.
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 rela-
tive numerical distribution over the Earth's surface, are con-
ditions 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 Mdiich 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 them-
selves, 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 man-
ner the consideration of" the form of the Earth and the inces-
sant 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 domam of the ocean (of the liquid por-
tions 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 cul-
ture. 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
requiren\ent for cosraical presentation awakened in me by the '
I
FKiUllK OF THE EARTlf. 163
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 knovt^ledge
that portions which have long- stood isolated become gradually
connected, and subject to higher laws. I only indicate the
empirical jiath 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."*
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 crys-
talline, 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 revolu-
tion gives evidence of having once been a soft or fluid mass.
Thus the Earth's compression constitutes one of the most an-
cient geognostic events, as every attentive reader of the book
of nature can easily discern ; and an analogous fact is pre-
sented in the case of the Moon, the perpetual direction of whose
axes toward the Earth, that is to say, the increased accumula-
tion of matter on that half of the Moon which is turned to-
ward us, determines the relations of the periods of rotation and
revolution, and is probably cotemporaneous with the earliest
epoch in the formative history of this satellite. The mathe-
matical 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
decrees refer. This mathematical surface is difi'ereiit from
that true physical surface which is alTected by all the acci-
dents and inequalities of the solid parts. f The whole figure
of the Earth is determined when we know the amount of the
* Plato, Phccdo, p. 97. (Arist., Metaph., p. 985.) Compare Hegel,
Philosophic der Geschichte, 1840, s. 16.
t Bessel, Allgemeine Betrachtungen uber Gradmessungeri nach astro-
nomisch-geoddtischen Arbeiten, at the conclusion of Bessel and Baeyer,
Gradmessung in Ostpreussen, s. 427. Regarding the accumulation ot"
matter on the side of the Moon turned toward us (a subject noticed
in an earlier part (jf the text), see Laplace, Expos, du Syst. du Monde,
p. 308.
164 ' COSMOS.
compression at the poles and the equatorial diameter ; m or-
der, however, to obtain a perfect representation of its form it
is necessary to have measurements in two directions, perpen-
dicular to one another.
Eleven measurements of degrees (or determinations of the
curvature of the Earth's surface in diflerent parts), of which
nine only belong to the present century, have made us ac-
quainted with the size of our globe, which Pliny named " a
point in the immeasurable universe."* 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,
PhiLoso2:)hice Naturalis Principia, that the compression of the
Earth, as a homogeneous mass, was -^^-^Xh.. Actual meas-
* Plin., ii., 68. Seneca, Nat. Qucest., Prcef., c. ii. " El mundo as
poco" (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 w^as not
long, if, as he observes, " we seek the east from the west." Compare
my Examen Crit. de VHist. de la Geogr. dn 15me Siecle, t. i., p. 83, and
t. ii., p. 327, where I have shown that the opinion maintained by De-
lisle, Fr6ret, and Gosselin, that the excessive differences in the state-
ments 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 Fer-
rer, in a proposition regai'ding the determination of the line of demark-
ation of the papal dominions.
t 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, consequent-
ly, to the investigation of the true figure of the Earth." Although Cas-
sini did not announce the amount of the compression of Jupiter (—jth)
till 1691 (Anciens MSmoires de V 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 yeai's before the publication of Newton's
Principia.
FIGURE OF THE EARTH. 165
urements, 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 g^o^h.
Three methods have been employed to investigate the curv-
ature of the Earth's surface, viz., measurements of degrees,
oscillations of the pendulum, and observations of the inequal-
ities in the Moon's orbit. The first is a direct geometrical
and astronomical method, while in the other two we determ-
ine from accurately observed movements the amount of the
forces which occasion those naovements, 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 strik-
ing 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 measure-
ments 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 ob-
ject 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
* According to Bessel's examination of ten measurements of degrees,
in which the error discovered by Puissant in the calculation of the
French measurements is taken into consideration (Schumacher, Astron.
Nackr., 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 _^_^_-j.^d ; the length of a mean degree of
the meridian, 57,013-109 tofses, or 364,596 feet, with an error of -\-
166 coriiVios.
of -g-g-g-tli. In accordance with this, the polar radius is 1 0,938
toises (69,944 feet), or about 11|- miles, shorter than the equa-
torial radius of our terrestrial spheroid. The excess at the
equator in consequence of the curvature of the upper surface
of the globe amounts, consequently, in the direction of gravi-
tation, to somevv^hat more than 4^th times the height of
Mont Blanc, or only 21 times the probable height of the
summit of the Dhawalagiri, in the Himalaya chain. The
lunar inequalities (perturbation in the moon'^s latitude and
longitude) give, according to the last investigations of Laplace,
almost the same result for the eUipticity as the measurements
of degrees, viz., 2-y¥^h. The results yielded by the oscillation
of the pendulum give, on the whole, a much greater amount
of compression, viz., •gjs'th.*
2-8403 toises, or 18-16 feet, whence the leugtli ofja geographical mile
is 3807-23 toises, or 6086-7 feet. Previous combinations of measure-
ments of degrees varied betvi^een gl^d and g^^th; thus Walbeck (Z>e
Forma et Magnitudine telluris in demensis arcubus Meridiani definiendis,
1819) gives 3 Q^ij^th : Ed. Schmidt {Lekrhichder Maikem. und Phi/s. Geo-
graphie, 1829, s. 5) gives -ggl^- 2d, as tlie mean of seven measures. Re-
specting the influence of great differences of longitude on the polar
compression, see Bibliotheqne Universelle, t. xxxiii., p. 181, and t. xxxv.,
p. 56 ; likev^^ise Connaissance des Term, 1829, p. 290. From the lunar
inequalities alone, Laplace {Expositioyi du Syst. dn Monde, p. 229) found
it, by tiie older tables of Biirg, to be «'y^th ; and subsequently, from
the hmar observations of Burckhardt and Bouvard, he fixed it at ■, g^.yth
(M^canique Cileste, t. v., p. 13 and 43).
* The oscillations of the pendulum give ^^^^th as the general result
of Sabine's great expedition (1822 and 1823, from the equator to 80°
north latitude) ; according to Freycinet, g^^^.-^d, exclusive of the experi-
ments instituted at the Isle of France, Guam, aiad Mowi (Mawi); ac-
cording to Forster, ^^^th ; according to Duperrey, ^^^th ; and ac-
cording to Liitke ('Partie Nautique, 1836, p. 232), -o^gth, calculated
from eleven stations. On the other hand, Mathieu ( Connaiss. des Temps,
1816, p. 330) fixed the amount at ^^_d, from observations made be-
tween Formentera and Dunkirk; and Biot, at —yth, from observations
between Formentera and the island of Unst. Compare Baily, Report
on Pendulum Experiments, in the Memoirs of the Royal Astronomical
Society, vol. vii., p. 96; also Borenius, in the Bulletin de V Acad, de St.
Pitersbourg, 1843, t. i., p. 2.5. The first proposal to apply the length of
the pendulum as a standard of measure, and to establish the third part
of the seconds pendulum (then supposed to be every where of equal
length) as a pes horarius, or general measure, that might be recovered
at any age and by all nations, is to be found in Huygens's Horologium
Oscillatorium, 1673, Prop. 2.5. A similar wish was afterward publicly
expressed, in 1742, on a monument erected at the equator by Bouguer,
La Condamine, and Godin. On the beautiful marble tablet which ex-
ists, as yet uninjured, in the old Jesuits' College at Quito, I have myself
read the inscription, Penduli simplicis (pquinoctialis unius minuti secundt
FIGURE OF THE EARTH. 167
Galileo, who first observed when a boy (having, probably,
suffered his thoughts to wander from the service) that the
height of the vaulted roof of a church might be measured by
the time of the vibration of the chandeliers suspended at dif-
ferent altitudes, could hardly have anticipated that the pendu-
lum would one day be carried from pole to pole, in ordof to
determine the form of the Earth, or, rather, that the unequal
density of the strata of the Earth affects the length of the sec-
onds pendulum by means of intricate forces of local attraction,
which are, however, almost regular in large tracts of land.
These geognostic relations of an instrument intended for the
measurement of time — this property of the pendulum, by
which, like a sounding line, it searches unknown depths, and
reveals in volcanic islands,=^ or in the declivity of elevated con-
tinental m.ountain chains,! dense masses of basalt and mela-
archetypus, meyisurce naturalis exemplar, niinam universalis ! From an
observation made by La Condamine, in his Journal du Voyage a I'Equa-
teur, 1751, p. 163, regarding parts of the inscription that were not tilled
up. and a slight difference between Bougner and himself respecting the
numbers, I was led to expect that I should tind considerable discrepan-
cies between the marble . tablet and the inscription as it had been de-
scribed in Paris; but, after a careful comparison, I mei'ely found two
perfectly unimportant ditfereuces ; "ex arcu graduum Sj^" instead of
"ex arcu graduum plusquam trium," and the date of 1745 instead of
1742. The latter circumstance is singular, because La Condamine re-
turned to Europe in November, 1744, Bouguer in June of the same year,
and Godin had left South America in July, 1744. The most necessary
and useful amendment to the numbers on this inscription would have
been the astronomical longitude of Quito. (Humboldt, Ttecueil d'Ob-
serv. Astroji., t. ii., p. 319-354.) Nonet's latitudes, engraved on Egyp-
' tian monuments, offer a more recent example of the danger presented
by the grave perpetuation of false or careless results.
* Respecting the augmented intensity of the attraction of gravitation
in volcanic islands (St. Helena, Ualan, Fernando de Noronha, Isle of
France, Guam, Mowi, and Galapagos), Rawak (Liitke, p. 240) being
an exception, probably in consequence of its proximity to the high
land of New Guinea, see Mathieu, in Delambre, Hist, de VAstronomie, au
ISwe Steele, p. 701.
t Numerous observations also show great irregularities iu the length
of the pendulum in the midst of continents, and which are ascribed to
local attractions. (Delambre, Mesure de la Miridienne, t. iii., p. 548;
Blot, in the M6m. de V Acad6mie des Sciences, t. viii., 1829, p. 18 and
23.) In passing over the South of France and Lombardy from west to
east, we find the minimum intensity of gravitation at Bordeaux ; from
thence it increases rapidly as we advance eastward, through Figeac,
Clermont-Ferrand, Milan, and Padua; and in the last town we find that
the intensity has attained its maximum. The influence of the southern
declivities of the Alps is not merely dependent on the general size of
their mass, but (much more), in the opinion of Elie de Beaumont (Reck,
sitr les R6vol. de la Surface d>i Globe, 1830, p. 729). on the rocks of
meJaphyie and serpentiue. which have elttviited the cliain. On the
168 COSMOS.
phyre instead of cavities, render it difficult, notwithstandmg
the admirable simplicity of the method, to arrive at any great
result regarding the figure of the Earth from observation of
the oscillations of the pendulum. In the astronomical part of
the determination of degrees of latitude, mountain chains, or
the denser strata of the Earth, likewise exercise, although in a
less degree, an unfavorable influence on the measurement.
As the form of the Earth exerts a powerful influence on the
motions of other cosmical bodies, and especially on that of its
own neighboring satellite, a more perfect knowledge of the mo-
tion of the latter will enable us reciprocally to draw an infer-
ence regarding the figure of the Earth. Thus, as Laplace ably
remarks,* "An astronomer, without leaving his observatory,
may, by a comparison of lunar theory with true observations,
not only be enabled to determine the form and size of the
Earth, but also its distance from the Sun and Moon — results
that otherwise could only be arrived at by long and arduous
expeditions to the most remote parts of both hemispheres."
declivity of Ararat, which with Caucasus may be said to lie iii the cen-
ter of gravity of the old continent formed by Europe, Asia, and Africa,
the very exact pendulum experiments of Fedorow give indications, not
of subterranean cavities, but of dense volcanic masses. (Parrot, Reise
zum Ararat, bd. ii., s. 143.) In the geodesic operations of Carlini and
Plana, in Lombardy, differences ranging from 20" to 47"-8 have been
found between direct observations of latitude and the results of these
operations. (See the instances of Andrate and Mondovi, and those of
Milan and Padua, in the Operations Geodes. et Astron. potir la Mesure
d'un Arc du Parallele Moyen, t. ii., p. 347 ; Effemeridi Astron. di Mi-
lano, 1842, p. 57.) The latitude of Milan, deduced from that of Berne,,
according to the French triangulation, is 45° 27' 52", while, according
to direct astronomical observations, it is 45° 27' 35". As the perturba-
tions extend in the plain of Lombardy to Parma, which is far south of
thePo (Plana, Op6rat. Geod., t. ii., p. 847), it is probable that there are
deflecting causes concealed beneath the soil of the plain itself. Struve
has made similar experiments [ with corresponding results] in the most
level parts of eastern Europe. (Schumacher, Astron. Nachrichten, 1830,
No. 164, s. 399.) Regai'ding the influence of dense masses supposed to
lie at a small depth, equal to the mean height of the Alps, see the ana-
lytical expressions given by Hossard and Rozet, in the Comptes Rendus,
t. xviii., 1844, p. 292, and compare them with Poisson, Traiti dc M6-
caniqjie (2me ed.), t. i., p. 482. The earliest observations on the in-
fluence which dinerent. kinds of I'ocks exercise on the vibration of ihe
pendulum are those of Thomas Young, in the Philos. Transactions for
1819, p. 70-96. In drawing conclusions regarding the Earth's curva-
ture from the length of the pendulum, we ought not to overlook the
possibility that its crust may have undergone a process of hardening
previously to metallic and dense basaltic masses having penetrated froc3
great depths, through open clefts, and approached near the surface.
* Laplace, Expos, du Syst. du Monde, p. 231.
DENSITY OF THE EARTH. 169
The compression which may be inferred from lunar inequali-
ties affords an advantage not yielded by individual measure-
ments of degrees or experiments w^ith the pendulum, since it
gives a mean amount which is referable to the whole planet.
The comparison of the Earth's compression with the velocity
of rotation . shows, further, the increase of density from the
strata from the surface toward the center — an increase which
a comparison of the ratios of the axes of Jupiter and Saturn
with their times of rotation likewise shows to exist in these
two large planets. Thus the knowledge of the external form
of planetary bodies leads us to draw conclusions regarding their
internal character.
Th# northern and southern hemispheres appear to present
nearly the same curvature under equal degrees of latitude, but,
as has already been observed, pendulum experiments and
measurements of degrees yield such different results for indi-
vidual portions of the Earth's surface that no regular figure
can be given which would reconcile all the results hitherto
obtained by this method. The true figure of the Earth is to
a regular figure as the uneven surfaces of water in motion are
to the even surface of water at rest.
When the Earth had been measured, it still had to bo
weighed. The oscillations of the pendulum* and the plum-
met have here likewise served to determine the mean density
of the Earth, either in connection with astronomical and geo-
detic operations, with the view of finding the deflection of the
plummet from a vertical line in the vicinity of a mountain, or
by a comparison of the length of the pendulum in a plain and
on the summit of an elevation, or, finally, by the employment
of a torsion balance, which may be considered as a horizon-
tally vibrating pendulum for the measurement of the relative
density of neighboring strata. Of these three methods! the
* La Caille's pendulum measurements at the Cape of Good Hope,
which have been calculated with much care by Mathieu (Delarabre,
Hist, de VAstr-on. an ISme Siecle, p. 479), give a compression of ^^j-.^^th;
but, from several comparisons of observations made in equal latitudes
in the two hemispheres (New HoUmid and. the Malouines (Falkland
Islands), compared with Barcelona, New York, and Dunkirk), there is
»as yet no reason for supposing that the mean compression of the south-
ern hemisphere is greater than that oithe northern. (Blot, in the M6in.
de VAcad. des Sciences, t. viii., 1829, p. 39-41.)
t The three methods of observation give the ibllowing results: (1.) by
the deflection of the plumb-line in the proximity of the Shehallieu
Mountain (Gaelic, Thichallin) in Perthshire, 4-713, as determined by
Maskelyne, Kutton, and Playfair (1774-1776 and 1810), according to a
method that had been proposed by Newton; (2.) by pendulum vibra
Vol. I — H
170 " COSMOS.
last IS the most certain, since it is independent of the difficult
determination of the density of the mineral masses of which
the spherical segment of the mountain consists near which the
observations are made. According to the most recent experi-
ments of Reich, the result obtained is 5'44 ; that is to say, the
mean density of the whole Earth is 5-44 times gireater than
that of pure water. As, according to the nature of the min-
eralogical strata constituting the dry continental part of the
Earth's surface, the mean density of this portion scarcely
amounts to 2*7, and the density of the dry and liquid surface
conjointly to scarcely 1*6, it follows that the elliptical un-
equally compressed layers of the interior must greatly increase
m density toward the center, either through pressure or^owing
to the heterogeneous nature of the substances. Here again
we see that the vertical, as well as the horizontally vibrating
pendulum, may justly be termed a geognostical instrument.
The results obtained by the employment of an instrument
ol" this kind have led celebrated physicists, according to the
difference of the hypothesis from which they started, to adopt
tions ou niountaiiis, 4*837 (Carlini's observations on Mount Cenis coni^
pared with Biot's observations at Bordeaux, Effemer. Astron. di Milano,
1824, p. 184); (3.) by the torsion balance used by Cavendish, with an
ap{)aratus originally devised by Mitchell, 5*48 (according to Hutton's
revision of the calculation, 5*32, and according to that of Eduai'd
Schmidt, 5*52; Lehrbitch der Math. Geographic, bd. i., s. 487); by the
torsion balance, according to Reich, 5-44, In the calculation of these
experiments of Professor Reich, which have been made with masterly
accuracy, the original mean result was 5-43 (with a probable error of
only 0233), a result which, being increased by the quantity by which
the Earth's centrifugal force diminishes the force of gravity for the lati-
tude of Freiberg (50"^ 55'), becomes changed to 5*44. The employ-
ment of cast iron instead of lead has not presented any sensible differ-
ence, or none exceeding the limits of errors of observation, hence dis-
closing no traces of magnetic influences. (Reich, Versjiche uberdie mitt-
lere Dichtigheit der Erde, 1838, s. 60, 62, and QQ.) By the assumption
of too slight a degree of ellipticity of the Earth, and by the uncertainty
of the estimations regarding the density of rocks on its surface, the
mean density of the Earth, as deduced from exiieriments on and near
mountains, was found about one sixth smaller than it really is, name-
ly, 4-761 (Laplace, Mican. CHesfe, t. v., p. 46), or 4-783. (Eduard
Schmidt, Lehrh. der Math. Geogr., bd. i., ^ 387 uud 418.)' On Halley's
hypothesis of the Earth being a hollow sphere (noticed ia page 171),
which was the germ of Franklin's ideas concerning earthquakes, see
Philos. Trans, for the year 1693, vol. xvii., p. 563 {On the Structure of
the laternal Parts of the Earth, and the concave habited Arch of the
Shell). Halley regarded it as more worthy of the Creator " that tlio
Earth, like a house of several stories, should be inhabited both without
and within. For light in the hullovv sphere (p. 576) provision might ii*
Bome manner be contrived."
DENSITY OF THE EARTH. 171
entirely opposite views regarding the nature of the interior of
the globe. It has been computed at what depths liquid or
even gaseous substances would, from the pressure of their
own superimposed strata, attain a density exceeding that of
platinum or even iridium ; and in order that the compression
which has been determined within such narrow limits migh*
be brought into harmony with the assumption of simple and
infinitely compressible matter, Leslie has ingeniously conceived
the nucleus of the world to be a hollow sphere, filled with an
assumed " imponderable matter, having an enormous force of
expansion." These venturesome and arbitrary conjectures
have given rise, in wholly unscientific circles, to still more
fantastic notions. The hollow sphere has by degrees been
peopled with plants and animals, and two small subterranean
revolving planets — Pluto and Proserpine — were imaginatively
supposed to shed over it their mild light ; as, however, it was
further imagined that an ever-uniform temperature reigned in
these internal regions, the air, which was made self-luminous
by compression, might well render the planets of this lower
world unnecessary. Near the north pole, at 82° latitude,
whence the polar light emanates, was an enormous opening,
through which a descent might be made into the hollow
sphere, and Sir Humphrey Davy and myself were even pub-
licly and frequently invited by Captain Symmes to enter upon
this subterranean expedition : so powerful is the morbid in-
clination of men to fill unknown spaces with shapes of won-
der, totally unmindful of the counter evidence furnished by
well-attested facts and universally acknowledged natural laws.
Even the celebrated Halley, at the end of the seventeenth
century, hollowed out the Earth in his magnetic speculations I
Men were invited to believe that a subterranean freely-ro-
tating nucleus occasions by its position the diurnal and an-
nual changes of magnetic declination. It has thus been at-
tempted in our own day, with tedious solemnity, to clothe in
a scientific garb the quaintly-devised fiction of the humorous
Ilolberg.*
* [The work referred to, one of the wittiest prodnctions of tlie learned
Norwegian satirist and dramatist Holberg, was written in Latin, and
first appeared under the following title : Nicolai Klimii Her suhterra-
neum novum tellvris theonam ac historiam qr/intce monarchice adhuc «o-
his incogvAtce exhibens e hibliotheca b. Abelini. Hafniee ct Lipsice snmt.
Jac. Prenss, 1741. An admirable Danish translation of this learned
but severe satire on the institutions, morals, and manners of the inhab*
itants of the upper Earth, appeared at Copenhagen in 1789, and was
entitled Niels Klim^s ujiderjordiske reise ved Lndwig Holberg, oversat
172 COSMOS.
The figure of the Earth and the amount of solidification
(density) w^hich it has acquired are intimately connected with
the forces by which it is animated, in so far, at least, as they
have been excited or awakened from without, through its
planetary position with reference to a luminous central body.
Compression, when considered as a consequence of centrifugal
force acting on a rotating mass, explains the earUer condition
of fluidity of our planet. During the solidification of this
fluid, which is commonly conjectured to have been gaseous
and primordially heated to a very high temperature, an enor-
mous quantity of latent heat must have been liberated. If
the process of solidification began, as Fourier conjectures, by
radiation from the cooling surface exposed to the atmosphere,
the particles near the center would have continued fluid and
hot. As, after long emanation of heat from the center toward
the exterior, a stable condition of the temperature of the
Earth would at length be established, it has been assumed
that with increasing depth the subterranean heat likewise
uninterruptedly increases. The heat of the water which
flows from deep borings (Artesian wells), direct experiments
regarding the temperature of rocks in mines, but, above all,
the volcanic activity of the Earth, shown by the flow of molt-
en masses from open fissures, afibrd unquestionable evidence
of this increase for very considerable depths from the upper
strata. According to conclusions based certainly upon mere
analogies, this increase is probably much greater toward the
center.
That which has been learned by an ingenious analytic cal-
culation, expressly perfected for this class of investigations,*
efter den Latinske original af Jens Baggesen. Holberg, who studied
for a time at Oxford, was born at Bergen in 1685, and died in 1754 as
Rector of the University of Copenhagen.] — Tr.
* Here we must notice the admirable analytical labors of Fourier,
Biot, Laplace; Poisson, Duhamel, and Lame. In his Th6orie Mathema-
tique de la Chaleur, 1835, p. 3, 428-430, 436, and 521-524 (see, also,
De la Rive's abstract in the Bibliotheque Universelle de Geneve), Pois-
son has developed an hypothesis totally different from Fourier's view
( Theorie Analytique de la Chaleur.) He denies the present fluid state
of the Earth's center ; he believes that " in cooling by radiation to the
medium surrounding the Earth, the parts which were first solidified
Bunk, and that by a double descending and ascending current, the great
inequality was lessened which would have taken place in a solid body
cooling from the surface." It seems more probable to this great ge-
ometer that the solidification began in the parts lying nearest to the
center : " the phenomenon of the increase of heat with the depth does
not extend to the whole mass of the Earth, and is merely a consequence
of the motion of our planetary system in space, of which some parts
INTERNAL HEAT OF THE EARTH. 173
reguiding the motion of heat in homogeneous metallic sphe-
roids, must be applied with much caution to the actual char-
acter of our planet, considering our present imperfect knowl-
edge of the substances of which the Earth is composed, the
difference in the capacity of heat and in the conducting power
of different superimposed masses, and the chemical changes
experienced by solid and liquid masses from any enormous
compression. It is with the greatest difficulty that our pow-
ers of comprehension can conceive the boundary line which di-
vides the fluid mass of the interior from the hardened mineral
masses of the external surface, or the gradual increase of the
solid strata, and the condition of semi-fluidity of the earthy
substances, these being conditions to which known laws of
hydraulics can only apply under considerable modifications.
The Sun and Moon, which cause the sea to ebb and flow,
fliost probably also affect these subterranean depths. We
may suppose that the periodic elevations and depressions of
the molten mass under the already solidified strata must have
caused inequalities in the vaulted surface from the force of
pressure. The amount and action of such oscillations must,
however, be small ; and if the relative position of the attract-
ing cosmical bodies raiay here also excite " spring tides," it is
certainly not to these, but to more powerful internal forces,
that we must ascribe the movements that shake the Earth's
surface. There are groups of phenomena to whose existence
it is necessary to draw attention, in order to indicate the
universality of the influence of the attraction of the Sun and
Moon on the external and internal conditions of the Earth,
however little we may be able to determine the quantity of
this influence.
According to tolerably accordant experiments in Artesian
wells, it ha? been shown that the heat increases on an average
about 1° foi every 54-5 feet. If this increase can be reduced
are of a very different temperature from others, iu consequence of stel-
lar heat (chaleur stellah*e)." Thus, accoi'ding to Poisson, the warmth
of the water of our Artesian wells is merely that which has penetrated
into the Earth from without ; and the Earth itself " might be regarded
as in the same circumstances as a mass of rock conveyed from the
equator to the pole in so short a time as not to have entirely cooled.
The .ncrease of temperature in such a block wtiiuld not extend to the
central strata." The physical doubts which have reasonably been
entertained against this extraordinary cosmical view (which attributes
to the regions of space that which probably is more dejieiident on the
first transition of matter condensing from the gaseo-fluid into the solid
state) will be found collected in Poggendorf 's Annalen, bd. x.xxix,, a.
93-100.
174 COSMOS.
to arithmetical relations, it will follow, as I have already ob-
served,* that a stratum of granite would be in a state of fusion
at a depth of nearly twenty-one geographical miles, or between
four and five times the elevation of the highest summit of the
Himalaya.
We must distinguish in our globe three different modes for
the transmission of heat. The first is periodic, and affects
the temperature of the terrestrial strata according as the heat
penetrates from above downward or from below upward, being
influenced by the different positions of the Sun and the sea-
sons of the year. The second is likewise an efiect of the Sun,
although extremely slow : a portion of the heat that has pene-
trated into the equatorial regions moves in the interior of the
globe toward the poles, where it escapes into the atmosphere
and the remoter regions of space. The third mode of trans-
mission is the slowest of all, and is derived from the seculaT
cooling of the globe, and from the small portion of the primi-
tive heat which is still being disengaged from the surface.
* See the Introduction. This increase of temperature has been found
in the Puits de Greuelle, at Paris, at 58'3 feet ; in the boring at the new
salt-works at Minden, almost 53*6 ; at Pregny, near Geneva, according
to Auguste de la Rive and Marcet, notwithstanding that the uiouth oi
the boring is 1609 feet above the level of the seaj it is also 53-6 feet.
This coincidence between the results of a method first proposed by
Arago in the year 1821 {Annuaire du Bureau des Longitudes, 1835, p.
234), for three different mines, of the absolute depths of 1794, 2231,
and 725 feet respectively, is remarkable. The two points on the Earth,
lying at a small vertical distance from each other, whose annual mean
temperatures are most accurately known, are probably at the spot on
which the Paris Observatory stands, and the Caves de I'Observatoire
beneath it: the mean temperature of the former is 51'^"5, and of the
latter 53°-3, the ditference being lo-8 for 92 feet, or 1° for 51-77 feet.
(Poisson, Thiorie Math, de la Chaleur, p. 415 and 462.) In the course
of the last seventeen years, from causes not yet perfectly understood,
but probably not connected with the actual temperature of the caves,
the thermometer standing there has risen very nearly 0'-'*4. Although
in Artesian wells there are sometimes slight errors from the lateral
permeation of water, these errors are less injurious to the accuracy of
conclusions than those resulting from cuiTents of cold air, which are
almost always present in mines. The general result of Reich's great
work on the temperature of the mines in the Saxony mining districts
gives a somewhat slower increase of the terrestrial heat, or 1° to 76*3
feet. (Reich, Beob. uber die Te^nperatur des Gesteins in verschieden en
Tiefen, 1834, s. 134.) Phillips, however, found (Pogg., Annalen, bd.
xxxiv., s. 191), in a shaft of the coal-mine of Monk-wearmouth, near
Newcastle, in which, as I have already remarked, excavations are going
on at a depth of about 1500 feet below the level of the sea, an increase
of 1° to 59*06 feet, a result almost identical with that found by Arago
in the Puits de Grenell.
MEAN TEMPER A TURK OF THE EARTH. 175
This loss experienced by the central heat must have been very
considerable in the earliest epochs of the Earth's revolutions,
but within, historical periods it has hardly been appreciable
by our instruments. The surface of the Earth is therefore
situated between the glowing heat of the inferior strata and
the universal regions of space, whose temperature is probably
below the freezing-point of mercury.
The periodic changes of temperature which have been
occasioned on the Earth's surface by the Sun's position and
by meteorological processes, are continued in its interior,
although to a very inconsiderable depth. The slow conduct-
ing power of the ground diminishes this loss of heat in the
winter, and is very favorable to deep-rooted trees. Points
that lie at very different depths on the same vertical line
attain the maximum and minimum of the imparted tempera-
ture at very different periods of time. The further they are
removed from the surface, the smaller is this difference be-
tween the extremes. In the latitudes of our temperate zone
(between 48^ and 52°), the stratum of invariable temperature
is at a depth of from 59 to 64 feet, and at half that depth
the oscillations of the thermometer, from the influence of the
seasons, scarcely amount to half a degree. In tropical cli-
mates this invariable stratum is only one foot below the
surface, and this fact has been ingeniously made use of by
Boussingault to obtain a convenient, and, as he. believes, cer-
tain determination of the mean temperature of the air of
different places.* This mean temperature of the air at a
fixed point, or at a group of contiguous points on the surface,
is to a certaiij degree the fundamental element of the climato
and agricultural relations of a district ; but the mean tem-
perature of the whole surface is very different from that of
the globe itself. The questions so often agitated, whether the
mean temperature has experienced any considerable differences
in the course of centuries, whether the climate of a country
has deteriorated, and whether the winters have not become
milder and the summers cooler, can only be answered by
means of the thermometer ; this instrument has, however,
scarcely been invented more than two centuries and a half,
and its scientific application hardly dates back 120 years.
The nature and novelty of the means interpose, therefore, very
narrow limits to our investigation regarding the temperature
* Boussingault, Su7- la Profondeur a laqnelle se trouve la Coiiche de
Temperature invariable entre les Tropiqv.es, in the Annalcf de. Chimin
et de Physique, t. liii., 1833, p. 225-247.
176 COSMOS.
of the air. It is quite otherwise, however, with the solution
of the great problem of the internal heat of the whole Earth.
As we may judge of uniformity of temperature from the unal-
tered time of vibration of a pendulum, so we may also learn,
from the unaltered rotatory velocity of the Earth, the amount
of stability in the mean temperature of our globe. This
msight into the relations between the length of the day and
the heat of the Earth is the result of one of the most brilliant
applications of the knowledge we had long possessed of the
movement of the heavens to the thermic condition of our
planet. The rotatory velocity of the Earth depends on its
volume ; and since, by the gTadual cooling of the mass by
radiation, the axis of rotation would become shorter, the rota-
tory velocity would necessarily increase, and the length of the
day diminish, with a decrease of the temperature. From the
comparison of the secular inequalities in the motions of the
Moon with the eclipses observed in ancient times, it follows
that, smc« the time of Hipparchus, that is, for full 2000
years, the length of the day has certainly not diminished by
the hundredth part of a second. The decrease of the mean
heat of the globe during a period of 2000 years has not, there-
fore, taking the extremest limits, diminished as much as a^gth
of a degree of Fahrenheit.*
This invariability of form presupposes also a great invaria-
bility in the distribution of relations of density in the interior
of the globe. The translatory movements, which occasion
the eruptions of our present volcanoes and of ferruginous lava,
and the filling up of previously empty fissures and cavities
with dense masses of stone, are consequently dnly to be re-
garded as slight superficial phenomena afiecting merely one
portion of the Earth's crust, which, from their smallness
when compared to the Earth's radius, become wholly insig-
nificant.
I have described the internal heat of our planet, both with
reference to its cause and distribution, almost solely from the
results of Fourier's admirable investigations. Poisson doubts
the fact of the uninterrupted increase of the Earth's heat
* Laplace, Exp. dit, Syst. du Monde, p. 229 and 263 ; Micaniqu6
Celeste, t. v., p. 18 and 72. It should be remarked that the fraction
5^th of a degree of Fahrenheit of the mercurial thermometer, given in
the text as the limit of the stability of the Earth's temperature since
the days of Hipparchus, rests on the assumption that the dilatation of
the substances of which the Earth is composed is equal to that of glass.
that is to say, y^.^o-oth for 1°. Regarding this hypothesis, see Arago
in the Annuaire for 1834, p. 177-190.
TERRESTRIAL MAGNETISM. 177
from the surface to the center, and is of opinion that all heat
has penetrated from without inward, and that the tempera-
ture of the globe depends upon the very high or very low
temperature of the regions of space through- which the solar
system has moved. This hypotiiesis, imagined by one of the
most acute mathematicians of our time, has not satisfied phys-
icists or geologists, or scarcely, indeed, any one besides its au-
thor. But, whatever mav be the cause of the internal heat
of our planet, and of its limited or unlimited increase in deep
strata, it leads us, in this general sketch of nature, through
the intimate connection of all primitive phenomena of matter,
and through the common bond by which molecular forces are
united, into the mysterious domain of magnetism. Changes
of temperature call forth magnetic and electric currents. Ter-
restrial magnetism, whose main character, expressed in the
three-fold manifestation of its forces, is incessant periodic va-
riabihty, is ascribed either to the heated mass of the Earth
itself,* or to those galvanic currents which we consider as
electricity in motion, that is, electricity moving in a closed
circuit.!
The mysterious course of the magnetic needle is equally
affected by time and space, by the sun's course, and by changes
of place on the Earth's surface. Between the tropics, the
hour of the day may be known by the direction of the needle
as well as by the oscillations of the barometer. It is affected
instantly, but only transiently, by the distant northern light
as it shoots from the pole, flashing in beams of colored light
across the heavens. When the uniform horary motion of the
needle is disturbed by a magnetic storm, the perturbation
manifests itself simultaneously, in the strictest sense of the
word, over hundreds and thousands of miles of sea and land,
or propagates itself by degrees, in short intervals of time, in
* William Gilbert, of Colchester, whom Galileo pronounced " great
to a degree that might be envied," said " magnus magnes ipse est globus
terrestris." He ridicules the magnetic mountains of Frascatori, the great
cotemporary of Columbus, as being magnetic poles : " rejicienda est
vulgaris opinio de montibus magneticis, aut rupe aliqua magnetica, aut
polo phantastico a polo mundi distante." He assumes the declination
of the magnetic needle at any given point on the surface of the Earth
to be invariable (variatio uuiuscujusque loci constans est), and refers
the curvatures of the isogenic lines to the configuration of continents
and the relative positions of sea basins, wrhich possess a weaker mag-
netic force than the solid masses rising above the ocean. (Gilbert, de
Magnate, ed. 1633, p. 42, 98, 152, and 155.)
t Gauss, Allgemeine Theorie des Erdmagnetismus, in the Resultate aut
■ den Beob. des Magnet. Vereins, 1838, s. 41, p. 56.
H 2
17^ COSMOS.
every direction over the Earth's surface.* In the former case,
the simultaneous manifestation of the storm may servCj with-
in certain hmitations. Hke Jupiter's satelhtes, fire-signals, and
well-observed falls of shooting stars, for the geographical
determination of degrees of longitude. We here recognize
with astonishment that the perturbations of two small mag-
netic needles, even if suspended at great depths below the
surface, can measure the distances apart at which they are
placed, teaching us, for instance, how far Kasan is situated
east of Gottingen or of the banks of the Seine. There are
also districts in the earth where the mariner, who has been
enveloped for many days in mist, without seeing either the
sun or stars, and deprived of all means of determining the
tirhe, may know with certainty, from the variations in the
inclination of the magnetic needle, whether he is at the north
or the south of the port he is desirous of entering.!
* There are also perturbations which are of a local character, and
do not extend themselves far, and are probably less deep-seated. Some
years ago I described a rare instance of this kind, in which an extraor-
dinaiy disturbance was felt in the mines at Freiberg, but was not per-
ceptible at Berlin. {Lettre de M. de Humboldt a Son Altesse Roy ale le
Due de Sussex- sti7' les moyens propres a perfectionner la Connaissance
ill Magn6tisme Terrestre, in Becquerel's TraiiS Experimental de VElec-
tricitS, t. vii., p. 442.) Magnetic storms, which were simultaneously
felt from Sicily to Upsala, did not extend from Upsala to Alten. (Gauss
and Weber, Resultate des Magnet. Vereins, 1839, $ 128; Lloyd, in the
Comptcs Rendus de I' Acad, des Sciences, t. xiii., 1843, Sem. ii., p. 725
and 827.) Among the numerous examples that have been recently
observed, of perturbations occurring simultaneously and extending over
wide portions of the Earth's sm-face, and which are collected in Sabine's
important work {Observ. on Days of unusual Magnetic Disturbance,
1843), one of the most i-emarkable is that of the 25th of September,
1841, which was observed at Toronto in Canada, at the Cape of Good
Hope, at Prague, and partially in Van Diemen's Land. The English
Sunday, on which it is deemed sinful, after midnight on Saturday, to
register an observation, and to follow out the great phenomena of crea-
tion in their perfect development, interrupted the observatious in Van
Diemen's Land, where, in consequence of the difference of the longi-
tude, the magnetic storm fell on the Sunday. {Observ., p. xiv., 78, 85,
and 87.)
t I have described, in Lametherie's Journal de Physique, 1804, t.
lix., p. 449, the application (alluded to in the text) of the jnagnetic in-
clination to the determination of latitude along a coast naming north
and south, and which, like that of Chili and Peru, is for a part of the
year enveloped in mist {gar7ia). In the locality I have just mentioned,
thi^ application is of the greater importance, because, in consequence
of the strong current running northward as far as to Cape Parena, navi-
gators incur a great loss of time if they approach the coast to the north
of the haven they are seeking. In the South Sea, from Callao de Lima
harbor to Truxillo, which differ from each other in latitude by 3° 57'
TERRESTRIAL MAHNETISM. 179
When the needle, by its sudden disturbance in its horary
course, indicates the presence of a magnetic storm, we are
stiJl unfortunately ignorant whether the seat of the disturbing
cause is to be sought in the Earth itself or in the upper re-
gions of the atmosphere. If we regard the Earth as a true
magnet, we are obliged, according to the views entertained
by Friedrich Gauss (the acute propounder of a general theory
of terrestrial magnetism), to ascribe to every portion of the
globe measuring one eighth of a cubic meter (or Sy'^-ths of a
French cubic foot) in volume, an average amount of magnet-
ism equal to that contained in a magnetic rod of 1 lb. weight.*
If iron and nickel, and probably, also, cobalt (but not chrome,
as has long been believed),! are the only substances which
become permanently magnetic, and retain polarity from a
certain coercive force, the phenomena of Arago's magnetism
of rotation and of Faraday's induced currents show, on the
other hand, that all telluric substances may possibly be made
transitorily magnetic. According to the experiments of the
I have observed a variation of the magnetic inclination amounting to
9° (centesimal division) ; and from Callao to Guayaquil, which differ in
latitude by 9° 50', a variation of 23^-5. (See my Relat. Hist., t. iii.,
p. 622.) At Guarmey (10° 4' south lat.), Huaura (11° 3' south lat.),
and Chancay (11° 32' south lat.), the incHnations are 6°-80, 9°, and
10°-3.5 of the centesimal division. The determination of position by
means of the magnetic inclination has this remarkable feature connected
with it, that where the ship's course cuts the isoclinal line almost per-
pendicularly, it is the only one that is independent of all determination
of time, and, consequently, of observations of the sun Or stars. It is
only lately that I discovered, for the first time, that as eaiiy as at the
close of the sixteenth century, and consequently hardly twenty years
after Robert Norman had invented the inclinatorium, William Gilbert,
in his gi-eat work De Magnete, proposed to determine the latitude by
the inclination of the magnetic needle. Gilbert {Physiologia Nova de
Magneie, lib. v., cap. 8, p. 200) commends the method as applicable
" a^re caliginoso." Edward Wright, in the introduction which he
added to his master's great work, describes this proposal as " worth
much gold." As he fell into the same error with Gilbert, of presum
ing that the isoclinal lines coincided with the geographical parallel
circles, and that the magnetic and geographical equators were identic-
al, he did not perceive that the proposed method had only a local and
very limited application.
* Gauss and Weber, Resvltate des Magnet. Vereins, 1838, § 31, s. 146.
+ According to Faraday (London and Edinburgh Philosophical Maga-
zine, 1836, vol. viii., p. 178), pure cobalt is totally devoid of magnetic
power. I know, however, that other celebrated chemists (Heinrich
Rose and Wohler) do not admit this as absolutely certain. If out of
two cai-efuUy-purified masses of cobalt totally free from nickel, one ap-
pears altogether non-magnetic (in a state of equilibrium), I think it
probable that the other owes its m;ignetic property to a want of purity ;
and this opinion coincides with Faraday's view.
180 COSMOS.
h'rst-mentioned of these great physicists, water, ice, glass, and
carbon affect the vibrations of the needle entirely in the same
manner as mercury in the rotation experiments.* Almost all
substances show themselves to be, in a certain degree,' mag-
netic when they are conductors, that is to say, when a current
of electricity is passing through them.
Although the knowledge of the attracting poAver of native
iron magnets or loadstones appears to be of very ancient date
among the nations of the West, there is strong historical evi-
dence in proof of the striking fact that the knowledge of the
directive power of a magnetic needle and of its relation to
terrestrial magnetism was peculiar to the Chinese, a people
living in the extremest eastern portions of Asia. More than
a thousand years before our era, in the obscure age of Codrus,
and about the time of the return of the Heraclidse to the Pel-
oponnesus, the Chinese had already magnetic carriages, on
which the movable arm of the figure of a man continually
pointed to the south, as a guide by which to find the way
across the boundless grass plains of Tartary ; nay, even in the
third century of our era, therefore at least 700 years before
the use of the mariner's compass in European seas, Chinese
vessels navigated the Indian Oceanf under the direction of
magnetic needles pointing to the south. I have shown, in
another work, what advantages this means of topographical di-
rection, and the early knowledge and application of the mag-
netic needle gave the Chinese geographers over the Greeks
and Romans, to whom, for instance, even the true direction
of the Apennines and Pyrenees always remained unknown. $
The magnetic power of our globe is manifested on the ter-
restrial surface in three classes of phenomena, one of which
exhibits itself in the varying intensity of the force, and the
two others in the varying direction of the inclination, and in
* Arago, in the Annales de Cliimie, t. xxxii., p. 214 ; Brewster, Treat-
ise on Magnetism, 1837, p. Ill; Baumgartner, in the Zeitschrift fur
Phys. und Mathem., bd. ii., s. 419.
t Humboldt, Examen Critique de VHist. de la Giographie, t. iii., p. 36.
X Asie Centrale, t. i., Introduction, p. xxxviii.-xlii. The Western
nations, the Greeks and the Romans, knew that magnetism could be
communicated to iron, and that that metal loould retain it for a length of
time. (" Sola hsec materia ferri vires, a magnate lapide accipit, retinet-
que longo tempore." Plin., xxxiv., 14.) The great discovery of the ter-
restrial directive force depended, therefore, alone on this, that no one
in the West had happened to observe an elongated fragment of magnet-
ic iron stone, or a magnetic iron rod, floating, by the aid of a piece of
wood, in water, or suspended in the air by a tbreac], in such a position
as to admit of free motion.
TERRESTRIAL MAGNETISM. 181
the horizontal deviation from the terrestrial meridian of the
spot. Their combined action may therefore be graphically
represented by three systems of lines, the isodynaniic, isodinic,
and isogonic (or those o 
