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books ever published, are as follows : —

1. Completeness. — It contains 114,000
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wanted.

2. Accuracy of Definition. — In this
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were most valuable, in correcting the faulty
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Esq., the Rev. Chauncey Goodrich, Prof.
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The Volume contains 1576 pages, more than 3000 Illustrations

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6. Pronunciation. — This has b<
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7. The Illustrative Citation?

labour has been spared to eniboc
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throw light on the definitions,
sess any special interest of tho
language.

8. The Synonyms. — These ar
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and are very complete, x

9. The Illustrations, which excee<
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HUHBOLDT'S COSMOS.

COSMOS:

A SKETCH

OF A

PHYSICAL DESCRIPTION OF THE UNIYEESE.

BY

ALEXANDER VON HUMBOLDT.

TRANSLATED FROM THE GERMAN,
BY

E, C. OTli AND W. S. DALLAS, F.L.S.

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GENERAL SUMMARY OF CONTENTS

YOLUME V. OF COSMOS.

INTRODUCTION to the special results of observation in the domain of
telluric phenomena . . . . pp. 1— 9

FIRST SECTION 9 — 162

Size, form, and density of the earth .... 9 — 34

Internal heat of the earth 34 — 48

Magnetic activity of the eartn 49 — 162

Historical portion 49 — 87

Intensity 87—101

Inclination 102 — 118

Declination 118—151

Polar light 151—162

SECOND SECTION 162—483

Keaction of the interior of the earth upon its surface 162, etc.

Earthquakes ; dynamic action, waves of concussion 165 — 183

Thermal springs 184 — 207

Gas-springs; salses, mud-volcanoes, Naphtha-springs 207 — 223

Volcanoes with and without structural frames (conical and bell-shaped
mountains) 224—483

Range of volcanoes from North (19|° N. L.) to South, as far as 46*
South latitude : Mexican volcanoes, pp. 281 and 401 (Jorullo, pp. 309,
323, note at p. 310) ; Cofre de Perote, p. 326, Cotopaxi, notes pp. 337 —
341. Subterranean eruptions of vapour, pp. 342 — 345. Central America,
pp. 268—278. New Granada and Quito, pp. 281—285, and notes;
(Antisana, pp.331 — 336, Sangay, p. 446 ; Tungurahua, p. 444; Coto-
paxi, pp. 338—9 ; Chimborazo, p. 461, note 80;) Peru and Bolivia,
p. 286, note; Chili, p. 287, note 75; (Antilles, p. 421, note 31).

VI SYNOPSIS.

Enumeration of all the active volcanoes in the Cordilleras, p. 285.
Relation of the tracts without volcanoes to those abounding in them,
p. 296, note 70 at 283 ; volcanoes in the North-west of America, to the
north of the parallel of the Rio Gila, pp. 403—419 ; review of all the
volcanoes not belonging to the New Continent, pp. 285 — 403 ; Europe,
pp. 349—350; islands of the Atlantic Ocean, p. 351 ; Africa, p. 354;
Asia; Continent, pp. 356— 367 ; Thian-shan, pp. 358— 359, 433, and
notes 42 — 48; (peninsula of Kamtschatka, pp. 362—367); Eastern
Asiatic Islands, p. 367; (island of Saghalin, Tarakai or Kara-
futo, notes 97 — 99, p. 305; volcanoes of Japan, p. 373; islands of
Southern Asia, pp. 377 — 382 ;) Java, pp. 298—307. The Indian Ocean,
pp. 382—388 ; the South sea, pp. 388 — 401.

Probable number of volcanoes on the globe, and their distribution on the
continents and islands pp. 421 — 431

Distance of volcanic activity from the sea, pp. 295-6, 432-3.
Regions of depression, pp. 431 — 436 ; Maars, Mine-funnels, pp. 231-3.
Different modes in which solid masses may reach the surface
from the interior of the earth, through a net-work of fissures in the
corrugated soil, without the upheaval or construction of conical or
dome-shaped piles, (basalt, phonolite, and some layers of pearl-stone
and pumice, seem to owe their appearance above the surface, not to
summit-craters, but to the effects of fissures). Even the effusions from
volcanic summits do not in some lava-streams consist of a continuous
fluidity, but of loose scoriae, and even of a series of ejected blocks and
rubbish ; there are ejections of stones which have not all been
glowing, pp. 308, 330, 332—337, 343—347, note 99 (p. 306) note 26
(page 335).

Mineralogical composition of the volcanic rock : generalisation of the
term trachyte, p. 452 ; classification of the trachytes, according to
their essential ingredients, into six groups or divisions in conformity
with the definitions of Gustav Rose; and geographical distributioa of
these groups, pp. 453 — 467 ; The designations andesite and andesine,
pp. 452 — 468, note, 471. Along with the characteristic ingredients of
the trachyte-formations there are also unessential ingredients, the
abundance or constant absence of which in volcanoes frequently very
near each other, deserves great attention, p. 473; Mica, ibid', glassy
felspar, p. 474 ; Hornblende and augite, p. 475 ; Leucite, p. 476 ;
olivine, p. 477 ; obsidian, and the difference of opinion on the forma-
tion of pumice, p. 479 ; subterranean pumice beds, remote from vol-
canoes, at Zumbalica in the Cordilleras of Quito, at Huichapa in the
Mexican Highland, and at Tschigem in the Caucasus, pp. 340 — 345.
Diversity of the conditions under which the chemical processes of vol-
canicity proceed in the formation of the simple minerals and their
association into trachytes, pp. 472, 473, 483.

CORRECTIONS AND ADDITIONS

BY THE AUTHOR.

PAGE 32. LINE 12.

A far more important result in reference to the density of the earth
than that obtained by Baily (1842) and Reich (1847 — 1850) has been
brought out by Airy's experiments with the pendulum, conducted with
such exemplary care in the Mines of Harton, in the year 1854. Accord-
ing to these experiments, the density is 6'566, with a probable error of
0-182 (Airy in the Philos. Transact, for 1856, p. 342). A slight modi-
fication of this numerical value, made by Professor Stokes on account
of the effect of the rotation and ellipticity of the earth, gives the den-
eity for Harton, which lies at 54° 48' north latitude, at 6'565, and for
the Equator at 6' 489.

PAGE 76. LINE 10.

Arago has left behind him a treasury of magnetical observations
(upwards of 52,600 in number) carried on from 1818 to 1835, which
have been carefully edited by M. Fedor Thoman, and published in the
(Euvres Completes de Francois Arago (t. iv, p. 498). In these observa-
tions, for the series of years from 1821 to 1830, General Sabine has
discovered the most complete confirmation of the decennial period of
magnetic declination, and its correspondence with the same period, in
the alternate frequency and rarity of the solar spots (Meteorological
Essays, London, 1855, p. 350). So early as the year 1850, when Schwabe
published at Dessau his notices of the periodical return of the solar
spots (Cosmos, vol. iv, p. 397), two years before Sabine first showed the
decennial period of magnetic declination to be dependent on the solar
spots (in March, 1852, Phil. Tr. for 1852, p. i, pp. 116—121 ; Cosmo*,
vol. v, p. 76, note), the latter had already discovered the important
result, that the sun operates on the earth's magnetism by the magnetic
power proper to its mass. He had discovered (Phil. Tr. for 1850, p. i,
p. 216, Cosmos, vol. v, p. 140), that the magnetic intensity is greatest,
and that the needle approaches nearest to the vertical direction, when
the earth is nearest to the sun. The knowledge of such a magnetical
operation of the central body of our planetary system, not by its heat-
producing quality, but by its own magnetic power, as well as by changes
in the Photosphere (the size and frequency of funnel-shaped openings),
gives a higher cosmical interest to the study of the earth's magnetism
and to the numerous magnetic observatories (Cosmos, vol. 1, p. 184 ;
vol. v, p. 73) now planted over Russia and Northern Asia, since the
resolutions of 1829, and over the colonies of Great Britain since 1840 —
1850. (Sabine, in the Proceedings of the Roy. Soc. vol. viii, No. 25, p. 400
aud in the Phil Trans, for 1856. p. 362).

CORRECTIONS AND ADDITIONS.

PAGE 85. LINE 9.

Though the nearness of the moon in comparison with the sun does
not seem to compensate the smallness of her mass, yet the already well
ascertained alteration of the magnetic declination in the course of a
lunar day, the lunar-diurnal magnetic variation (Sabine, in the Report
to the Brit. Assoc. at Liverpool, 1854, p. 11, and for Hobart-town in the
Phil. Tr. for 1857, Art. i, p. 6), stimulates to a persevering observation
of the magnetic influence of the earth's satellite. Kreil has the great
merit of having pursued this occupation with great care, from 1839
to 1852, (see his treatise Ueber den Einfluss des Mondes auf die hori-
zontale Component der Magnetischen Erdlcraft, in the Deukschriften der
Wiener AJcademie der Wiss. Mathem. Naturwiss. Classe, vol. v, 1853,
p. 45, and Phil. Trans, for 1856, Art. xxii). His observations, which
were conducted for the space of many years, both at Milan and Prague,
having given support to the opinion that both the moon and the solar
spots occasioned a decennial period of declination, led General Sabine
to undertake a very important work. He found that the exclusive in-
fluence of the sun on a decennial period, previously examined in rela-
tion to Toronto in Canada, by the employment of a peculiar and very
exact form of calculation, may be recognised in all the three elements
of terrestrial magnetism (Phil. Trans, for 1856, p. 861), as shown by
the abundant testimony of hourly observations onrried on for a course
of eight years at Hobart Town, from January 1841 to December 1848.
Thus both hemispheres furnished the same result as to the operation
of the sun, as well as the certainty " that the lunar-diurnal variation
corresponding to different years shows no conformity to the inequality
manifested in those of the solar-diurnal variation. The earth's induc-
tive action, reflected from the moon, must be of a very little amount."
(Sabine, in the Phil. Tr. for 1857, Art. i, p. 7, and in bl>e Proceedings
of the Royal Soc. vol. viii, No. 20, p. 404). The magnetic portion of
this volume having been printed almost three years ago, it seemed
especially necessary, with reference to a subject which has so long
been a favourite one with me, that I should supply what was wanting
by some additional remarks.

INTRODUCTION.

SPECIAL RESULTS OF OBSERVATION IN THE DOMAIN"
OF TELLURIC PHENOMENA.

Ix a work embracing so wide a field as the Cosmos, which
aims at combining perspicuous comjfrehensibility with general
clearness, the composition and co-ordination of the whole
are perhaps of greater importance than copiousness of detail.
This mode of treating the subject becomes the more desirable
because, in the Book of Nature, the generalization of views,
both in reference to the objectivity of external phenomena
and the reflection of the aspects of nature upon the imagination
and feelings of man, must be carefully separated from the
enumeration of individual results. The first two volumes of
the Cosmos were devoted to this kind of generalization, in
which the contemplation of the Universe was considered as
one great natural whole, while at the same time care was
taken to show how, in the most widely remote zones, man-
kind had, in the course of ages, gradually striven to discover
the mutual actions of natural forces. Although a great accu-
mulation of phenomena may tend to demonstrate their causal
connection, a General Picture of Nature can only produce
fresh and vivid impressions when, bounded by narrow limits,
its perspicuity is not sacrificed to an excessive aggregation
of crowded facts.

As in a collection of graphical illustrations of the surface
and of the inner structure of the earth's crust, general maps
precede those of a special character, it has seemed to me that
in a physical description of the Universe it would be most
appropriate, and most in accordance with the plan of the
present work, if, to the consideration of the entire Universe
from general and higher points of view, I were to append in
the latter volumes those special results of observation upon

VOL. v. B

\

2 COSMOS.

which the present condition of our knowledge is more parti-
cularly based. These volumes of my work, must, therefore,
in accordance with a remark already made (Cosmos, vol. iii,
pp. 2 — 6), be considered merely as an expansion and more
careful exposition of the General Picture of Nature (Cosmos,
vol. i, pp. 62 — 369), and as the uranological or sidereal sphere
of the Cosmos was exclusively treated of in the two last
<jolumes, the present volume will be devoted to the con-
ideration of the telluric sphere. In this manner the ancient,
simple, and natural separation of celestial and terrestrial
objects has been preserved, which we find by the earliest
evidences of human knowledge to have prevailed among all
nations.

As in the realms of space, a transition to our own plane-
tary system from the region of the fixed stars, illumined by
innumerable suns, whether they be isolated or circling round
one another, or whether they be mere masses of remote
nebulae, is indeed to descend from the great and the universal
to the relatively small and special ; so does the field of our con-
templation become infinitely more contracted when we pass
from the collective solar system, which is so rich in varied
forms, to our own terrestrial spheroid, circling round the
sun. The distance of even the nearest fixed star, a Centauri,
is 263 times greater than the diameter of our solar system,
reckoned to the aphelion distance of the comet of 1680; and
yet this aphelion is 853 times further from the sun than our
earth (Cosmos, vol. iv, p. 546). These numbers, reckoning
the parallax of a Centauri at O."9187, determine approximately
both the distance of a near region of the starry heavens
from the supposed extreme solar system and the distance
of those limits from the earth's place.

Uraiiology, which embraces the consideration of all that
fills the remote realms of space, still maintains the character
it anciently bore, of impressing the imagination most deeply
and powerfully by the incomprehensibility of the relations
of space and numbers which it embraces ; by the known
order and regularity of the motions of the heavenly bodies ;
and by the admiration which is naturally yielded to the
results of observation and intellectual investigation. This
consciousness of regularity and periodicity was so early im-
pressed upon the human mind that it was often reflected in

INTRODUCTION. 3

those forms of speech, which refer to the ordained course of
the celestial bodies. The known laws which rule the celestial
sphere excite perhaps the greatest admiration by their sim-
plicity, based as they solely are, upon the mass and distri-
bution of accumulated ponderable matter and upon its forces
of attraction. The impression of the sublime, when it arises
from that which is immeasurable and physically great, passes
almost unconsciously to ourselves beyond the mysterious
boundary which connects the metaphysical with the physi-
cal, and leads us into another and higher sphere of ideas. The
image of the immeasurable, the boundless, and the eternal, is
associated with a power which excites within us a more
earnest and solemn tone of feeling, and which, like the
impression of all that is spiritually great and morally exalted,
is not devoid of emotion.

The effect which the aspect of extraordinary celestial
phenomena so generally and simultaneously exerts upon
entire masses of people, bears witness to the influence of
such an association of feelings. The impression produced
in excitable minds by the mere aspect of the starry vault
of heaven is increased by profounder knowledge, and by
the use of those means which man has invented to augment
his powers of vision, and at the same time enlarge the horizon
of his observation. A certain impression of peace and calm-
ness blends with the impression of the incomprehensible in
the universe, and is awakened by the mental conception of
normal regularity and order. It takes from the unfathom-
able depths of space and time those features of terror
which an excited imagination is apt to ascribe to them.
In all latitudes man, in the simple natural susceptibility
of his mind, prizes " the calm stillness of a starlit summer
night."

Although magnitude of space and mass appertains more
especially to the sidereal portion of cosmical delineation, and
the eye is the only organ of cosmical contemplation, our
telluric sphere has, on the other hand, the preponderating
advantage of presenting us with a greater and a scientifically
distinguishable diversity in the numerous elementary bodies
of which it is composed. All our senses bring us in contact
with terrestrial nature, and while astronomy, which, as the
knowledge of moving luminous celestial bodies is most acces-

B2

4 COSMOS.

sible to mathematical treatment, has been the means of in-
creasing in the most marvellous manner the splendour of the
higher forms of analysis, and has equally enlarged the limits
of the extensive domain of optics ; our earthly sphere, on
the other hand, by its heterogeneity of elements, and by the
complicated play of the expressions of force inherent in matter,
has formed a basis for chemistry, and for all those branches
of physical science which treat of phenomena, that have not
as yet been found to be connected with vibrations generating
heat and light. Each sphere has, therefore, in accordance
with the nature of the problems which it presents to our
investigation, exerted a different influence on the intellectual
activity and scientific knowledge of mankind.

All celestial bodies, excepting our own planet and the
aerolites which are attracted by it, are, to our conception com-
posed only of homogeneous gravitating matter, without any
specific or so-called elementary difference of substances.
Such a simple assumption is, however, not by any means
based upon the inner nature and constitution of these remote
celestial orbs, but arises merely from the simplicity of the
hypotheses, which are capable of explaining and leading us
tc predict the movements of the heavenly bodies. This
idea arises, as I have already had occasion frequently to re-
mark (Cosmos, vol. i, pp. 44 — 49 and pp. 124 — 125 ; vol. iii,
pp. 2, 18, and 22 — 28), from, the exclusion of all recognition
of heterogeneity of matter, and presents us with the solu-
tion of the great problem of celestial mechanics, in which
all that is variable in the uranological sphere is subjected to
the sole control of dynamical laws.

Periodical alternations of light upon the surface of the
planet Mars do indeed point, in accordance with its different
reasons of the year, to various meteorological processes, and
to the polar precipitates excited by cold in the atmosphere of
that planet, (Cosmos, vol. iv, p. 504). Guided by analogies
and reasoning, we may indeed here assume the presence of
ice or snow (oxygen and hydrogen), as in the eruptive
masses or the annular plains of the moon we assume the
existence of different kinds of rock on our satellite, but direct
observation can teach us nothing in reference to these points.
.urea Newton ventured only on conjectures regarding the
elementary; constitution of the planets which belong to our

INTRODUCTION. 0

own solar system, as we learn from, an important conversa-
tion which he had at Kensington with Conduit (Cosmos,
vol. i, p. 120). The uniform image of homogeneous gravi-
tating matter conglomerated into celestial bodies has occu-
pied the fancy of mankind in various ways, and mythology
has even linked the charm of music to the voiceless regions
within the realms of space (Cosmos, vol. iv, pp. 431 — 434).

Amid the boundless wealth of chemically varying sub-
stances, with their numberless manifestations of force — amid
the plastic and creative energy of the whole of the organic
world, and of many inorganic substances — amid the meta-
morphosis of matter which exhibits an ever-active appear-
ance of creation and annihilation, the human mind, ever
striving to grasp at order, often yearns for simple laws of
motion in the investigation of the teiTestrial sphere. Even
Aristotle in his Physics states, that " the fundamental prin-
ciples of all nature are change and motion ; he who does not
recognise this truth recognises not nature herself" (Phys.
Auscult. iii, 1 p. 200 Bekker), and referring to the difference
of matter (" a diversity in essence "), he designates motion in
respect to its qualitative nature, as a metamorphosis,
«XXouo<rc9, very different from mere mixture, /*/£*?, and a
penetration which does not exclude the idea of subsequent
separation (De Gener. et Corrupt, i, 1 p. 327).

The unequal ascent of fluids in capillary tubes — the endos-
mosis which is so active in all organic cells, and is probably a
consequence of capillarity — the condensation of different
kinds of gases in porous bodies (of oxygen in spongy plati-
num, with a pressure which is equal to a force of more than
700 atmospheres, and of carbonic acid in boxwood charcoal,
when more than one-third is condensed in a liquid state
on the walls of the cells) — the chemical action of contact-
substances which, by their presence occasion or destroy (by
catalysis) combinations without themselves taking any part
in them — all these phenomena teach us that bodies at in-
finitely small distances exert an attraction upon one another,
which depends upon their specific natures. We cannot
conceive such attractions to exist independently of motions,
which must be excited by them although inappreciable to
our eyes.

We are still entirely ignorant of the relations which reci-

6 COSMOS.

procal molecular attraction as a cause of unceasing motion on
the surface, and very probably also in the interior of the
earth's body, exerts upon the attraction of gravitation, by
which the planets as well as their central body are main-
tained in constant motion. Even the partial solution of this
purely physical problem would yield the highest and most
splendid results that can be attained in these paths of inquiry,
by the aid of experimental and intellectual research. I pur-
posely abstain in these sentences from associating (as is qom-
monly done) the name of Newton with that law of attraction,
which rules the celestial bodies in space at boundless dis-
tances, and which is inversely as the square of the distance.
Such an association implies almost an injustice towards the
memory of this great man, who had recognised both these
manifestations of force, although he did not separate them
with sufficient distinctness, for we find — as if in the felicitous
presentiment of future discoveries — that he attempted in the
Queries to his Optics to refer capillarity and the little that
was then known of chemical affinity to universal gravita-
tion (Laplace, Expos, du Syst. du Monde, p. 384. Cosmos,
vol. iii, p. 23).

As in the physical world, more especially on the borders
of the sea, delusive images often appear which seem for a
time to promise to the expectant discoverer the possession of
some new and unknown land ; so, on the ideal horizon of the
remotest regions of the world of thought, the earnest inves-
tigator is often cheered by many sanguine hopes, which
vanish almost as quickly as they have been formed. Some
of the splendid discoveries of modern times have undoubtedly
been of a nature to heighten this expectation. Among these
we may instance contact-electricity — magnetism of rotation,
which may even be excited by fluids, either in their aqueous
form or consolidated into ice — the felicitous attempt of con-
sidering all chemical affinity as the consequence of the elec-
trical relations of atoms with a predominating poiar force —
the theory of isomorphous substances in its application to the
formation of crystals — many phenomena of the electrical
condition of living muscular fibre — and lastly, the knowledge
which we have obtained of the influence exerted by the sun's
position, that is to say, the thermic force of the solar rays,
upon the greater or lesser magnetic capacity and conducting

INTRODUCTION. T

power of one of the constituents of our atmosphere, namely,
oxygen. When light is unexpectedly thrown upon any pre-
viously obscure group of phenomena in the physical world,
we may the more readily believe that we are on the
threshold of new discoveries, when we find that these rela-
tions appear to be either obscure, or even in opposition to
already established facts.

I have more particularly adduced examples in which the
dynamic actions of attracting forces seem to show the course by
which we may hope to approximate towards the solution of the
problem of the original, unchangeable, and hence named the
elementary heterogeneity of substances (for instance, oxygen,
hydrogen, sulphur, potassium, phosphorus, tin, &c.), and of the
amount of their tendency to combine, in other words, their che-
mical affinity. Differences of form and mixture are, I would
again repeat, the only elements of our knowledge of matter ;
they are the abstractions under which we endeavour to com-
prehend the all-moving universe, both as to its size and com-
position. The detonation of the fulminates under a slight
mechanical pressure, and the still more formidable explosion
of terchloride of nitrogen, which is accompanied by fire,
contrast with the detonating combination of chlorine and
hydrogen, which explodes when the sun's rays fall directly
upon it (more especially the violet rays). Metamorphosis,
union, and separation afford evidence of the eternal circu-
lation of the elements in inorganic nature no less than in
the living cells of plants and animals. "The quantity of
existing matter remains however the same, the elements
alone change their relative positions to one another."

We thus find a verification of the ancient axiom of
Anaxagoras, that created things neither increase nor de-
crease in the Universe, and that that which the Greeks
termed the destruction of matter was a mere separation of
parts. Our earthly sphere, within which is comprised all
that portion of the organic physical world, which is accessible
to our observation, is apparently a laboratory of death and
decay ; but that great natural process of slow combustion,
which we call decay, does not terminate in annihilation. The
liberated bodies combine to form other structures, and through
the agency of the active forces which are incorporated ill
them a new life germinates from the bosom of the earth.

RESULTS OF OBSERVATION IN THE TELLURIC PORTION
OF THE PHYSICAL DESCRIPTION OF THE UNIVERSE.

In the attempt to grasp the inexhaustible materials
afforded by the study of the physical world — or in other
words — to group phenomena in such a manner as to lacili-
tate our insight into their causal connection, general clear-
ness and lucidity can only be secured where special
details — more particularly in the long and successfully
cultivated fields of observation — are not separated from the
higher points of view of cosmical unity. The telluric
sphere, as opposed to the uranological, is separable into
two portions, namely, the inorganic and the organic depart-
ments. The former comprises the size, form, and density
of our terrestrial planet ; its internal heat ; its electro-mag-
netic activity ; the mineral constitution of the earth's crust ;
the reaction of the interior of the planet on its outer surface
which acts dynamically by producing earthquakes, and che-
mically by rock-forming, and rock-metamorphosing processes ;
the partial covering of the solid surface by the liquid ele-
ment— the ocean ; the contour and articulation of the up-
heaved earth into continents and islands ', and lastly the
general external gaseous investment (the atmosphere). The
second or organic domain comprises not the individual forms
of life which we have considered in the Delineation of Nature,
but the relations in space which they bear to the solid and
fluid parts of the earth's surface, the geography of plants and
animals, and the descent of the races and varieties of man
from one common, primary stock.

This division into two domains belongs to a certain extent
to the ancients, who separated from the vital phenomena of
plants and animals such material processes as change of form
and the transition of matter from one body to another. In
the almost total deficiency of all means for increasing the
powers of vision, the difference between the two organisms1
was based upon mere intuition, and in part upon the dogma
of self-nutrition (Aristot. de Anima, ii, It. i, p. 412, a 14,

1 See Cosmos, vol. iii, p. 54.

THE EARTH. 9

Bekker), and of a spontaneous incentive to motion. This kind
of mental comprehension which I have named intuition, to-
gether with that felicitous acumen in the power of combining
his ideas, which was so characteristic of the Stagyrite, led him
to the assumption of an apparent transition from the inani-
mate to the living, from the mere element to the plant, and
induced him even to adopt the view that in the ever ascend-
ing processes of plastic formation there were gradual and
intermediate stages connecting plants with the lower animals
(Aristot. de part. Animal, iv, 5, p. 681, a 12, and hist. Animal.
viii, 1, p. 588, a 4, Bekker). The history of organisms (taking
the word history in its original sense, and therefore in rela-
tion to the faunas and floras of earlier periods of time) is so
intimately connected with geology, with the order of suc-
cession of the superimposed terrestrial strata and with the
chronometrical annals of the upheaval of continents and
mountains ; that it has appeared most appropriate to me, on
account of the connection of great and widely diffused phe-
nomena, to avoid establishing the natural division of organic
and inorganic terrestrial life as the main element of classifi-
cation in a work treating of the Cosmos. We are not here
striving to give a mere morphological representation of the
organic world, but rather to arrive at bold and compre-
hensive views of nature, and the forces which she brings
into play.

I.

Size, Configuration, and Density of the Earth. — The Heat in
the interior of the Earth, and its distribution. — Magnetic
Activity, manifested in changes of Inclination, Declination,
and Intensity of the force under the influence of the Sun's
position in reference to the Heat and Rarefaction of the
Air. — Magnetic Storms. — Polar Light.

That which in all languages is comprehended under ety-
mologically differing symbolical forms by the expression
Nature, and which man, who originally refers everything

10 COSMOS.

I

to his own local habitation, has further designated aa
Terrestrial Nature is the result of the silent co-operation
of a system of active forces, whose existence we can
only recognise by means of that which they move, blend
together, and again dissever ; and which they in part deve-
lope into organic tissues (living organisms), which have the
power of re-producing like structures. The appreciation of
nature is excited in' the susceptible mind of man through
the profound impression awakened by the manifestation of
these forces. Our attention is at first attracted by the re-
lations of size in space exhibited by our planet, which seems
only like a handful of conglomerated matter in the immea-
surable universe. A system of co-operating forces, which
either tend to combine or separate (through polar influences),
shows the dependence of every part of nature upon other
parts, both in the elementary processes (as in the formation
of inorganic substances), and in the production and main-
tenance of life. The size and form of the earth, its mass,
that is to say, the quantity of its material parts, which
when compared with the volume determines its density, and
by means of the latter, under certain conditions, both the
constitution of the interior of the earth and the amount of its
attraction, are relations which stand in a more manifest, and
a more mathematically demonstrable dependence upon one
another than we observe in the case of the above named vital
processes, in the distribution of heat, in the telluric condi-
tions of electro-magnetism, or in the chemical metamorphoses
of matter. Conditions, which we are not yet able to deter-
mine quantitatively on account of a complication of pheno-
mena, may nevertheless be present, and may be demon-
strated through inductive reasoning.

Although the two kinds of attraction, namely, that which
acts at perceptible distances, as the force of gravity (the gra-
vitation of the celestial bodies towards one another), and
that which is manifested at immeasurably small distances, as
molecular or contact-attraction, cannot in the present con-
dition of science be reduced to one and the same law, yet it
is not on that account the less credible that capillary attrac-
tion and endosmosis, which is so important in reference to
the ascent of fluids, and in respect to animal and vegetable
physiology, may be quite as much affected by the force of gra-

THE EARTH. 11

vitation and its local distribution as electro-magnetic pro*
cesses and the chemical metamorphosis of matter. To refer
to extreme conditions, we may assume that if our planet had
only the, mass of the moon, and therefore almost six times
less intensity of gravity, the meteorological processes, the
climate, the hypsometrical relations of upheaved mountain
chains and the physiognomy of the vegetation would be quite
different from what they now are. The absolute size of our
planet which we are here considering, maintains its impor-
tance in the collective economy of nature merely by the re-
lations which it bears to mass and rotation ; for even in the
universe, if ohe dimensions of the planets, the quantitative
admixture of the bodies which compose them, their velo-
cities and distances from one another, were all to increase or
diminish in one and the same proportion, all the phenomena
depending upon relations of gravitation would remain un-
changed in this ideal macrocosmos, or microcosmos.2

a. Size, Figure, Ellipticity, and Density of the Earth.

(Expansion of the Picture of Nature, Cosmos, vol. i,

pp. 154—164.)

The earth has been measured and weighed in order to de-
termine its form, density, and mass. The accuracy which
has been incessantly aimed at in these terrestrial determina-
tions, has contributed, simultaneously with the solution of
the problems of astronomy, to improve instruments of mea-
surement, and methods of analysis. A very important part

2 " The law of reciprocal attraction which acts inversely as the square
of the distance is that of emanations, proceeding from a centre. It ap-
pears to be the law of all those forces, whose action is perceptible at
sensible distances, as in the case of electrical and magnetic forces. One
of the remarkable properties of this law is that, if the dimensions of all
the bodies in the universe, together with their mutual distances and
their velocities, were proportionally increased or diminished, they would
still describe curves precisely similar to those which they now describe ;
so that the universe, after being thus successively reduced to the smallest
conceivable limits, would still always present the same appearance to
the observer. These appearances are consequently independent of the
dimensions of the universe, as in virtue of the law of the ratio which
exists between force and velocity, they are independent of absolute
movement in space." — Laplace, Exposition du Syst. du Monde (Seme e"d.)(
p. 385.

12 COSMOS.

of the process involved in the measurement of a degree is
strictly astronomical, since the altitudes of stars determine
the curvature of the arc, whose length is found by the solution
of a series of triangles. The higher departments of mathe-
matics have succeeded, from given numerical data, in solving
the difficult problems of the figure of the earth, and the sur-
face of equilibrium of a fluid homogeneous, or dense shell-like
heterogeneous mass, which rotates uniformly round a solid
axis. Since the time of Newton and Huygens, the most dis-
tinguished geometricians of the eighteenth century have de-
voted themselves to the solution of these problems. It is well
that we should bear in mind that all the great results which
have been attained by intellectual labour and by mathe-
matical combinations of ideas, derive their importance not
only from that which they have discovered and which has
been appropriated by science, but more especially from the
influence which they have exerted on the development and
improvement of analytical methods.

" The geometrical figure of the earth, in contradistinction
to the physical,3 determines the surface which the super-
ficies of water would assume in passing through a net-work
of canals, connected with the ocean, and covering and inter-
secting the earth in every direction. The geometrical surface
intersects the directions of the forces vertically, and these
forces are composed of all the attractions emanating from the
individual particles of the earth, combined with the centri-
fugal force, which corresponds with its velocity of rota-
tion.4 This surface must be generally considered as approxi-
mating very closely to an oblate spheroid, for irregularities
in the distribution of the masses in the interior of the earth
will also, where the local density is altered, give rise to irre-
gularity in the geometrical surface, which is the product
of the co-operation of unequally distributed elements. The
physical surface is the direct product of the surface of

3 Gauss, Bestimmwng des JSreitenunterschiedes zwisclien den Sternwarten
von Gottingen und Altona, 1828, s. 73. (These two observatories,
by a singular chance, are situated within a few yards of the same
meridian.)

4 Bessel, Ueber den Einflms der Unregelmassigkeiten der Figur der Erdt
auf geoddtisclie Arbeiten und Hire Vergleichung mit astronomischen
Bestimmungen, in Schumachers Astron. Nachr. Bd. xiv, No. 329, s. 270,
and Bessel and Baeyer, Gradmtysung in Ostpreussen, 1838, s. 427 — 442.

THE FIGURE OF THE EARTH. 13

tho solid and fluid matter on the outer crust of the
earth." Although while it is not improbable, judging from
geological data, that the incidental alterations which are
readily brought about in the fused portions of the interior
of the earth, when they are moved by a change of position of
the masses, may even modify the geometrical surface by pro-
ducing curvature of the meridians and parallels in small
spaces, and at very widely separated periods of time ; the
physical surface of the oceanic parts of our globe is peri-
odically subjected to a change of place in the masses, occa-
sioned by the ebbing and flowing (or in other words the
local depression and elevation) of the fluid element. The
inconsiderable amount of the effects of gravity in continental
regions may indeed render a gradual change inappreciable to
actual observation ; and according to Bessel's calculation, in
order to increase the latitude of a place by a change of only
1", it must be assumed that there is a transposition in the
interior of the earth of a mass, whose weight (its density
being assumed to be that of the mean density of the earth) is
that of 7296 geographical cubic miles.* However large the
volume of this transposed mass may appear to us when we
compare it with the. volume of Mont Blanc, or Chimborazo,
or Kintschindjinga, our surprise at the magnitude of the
phenomenon soon diminishes when we remember that our
terrestrial spheroid comprises upwards of 1696 hundreds of
millions of such cubic miles.

Three different methods have been attempted although
with unequal success for solving the problem of the figure of
the earth whose connection with the geological question of
the earlier liquid condition of the rotating planetary bodies
was known at the brilliant epoch of Newton, Huygens
and Hooke.* These methods were the geodetico-astro-

5 Bessel, Ueber den Einfiuss der Vcrdnderungen ties Erdkorpers auf die
Polhohen, in Lindeuau und Bohnenberger, Zeitschi ift fur Astronomic.
Bd. v, 1818, s. 29. " The weight of the earth, expressed in German
pounds=9933 x 10.21, and that of the transposed mass = 947 x 10.14."

6 The theoretical labours of that time were followed by those of
Maclaurin, Clairaut, and d'Alembert, by Legendre and by Laplace.
To this latter period we may add the theorem advanced by Jacobi, in
1834, that ellipsoids of three unequal axes may, under certain conditions,
represent the figures of equilibrium no less than the two previously-
indicated ellipsoids of rotation. — See the treatise of this writer, whose

14 COSMOS.

nomical measurement of a degree, pendulum experiments,
and calculations of the inequalities in the latitude and longi-
tude of the moon. In the application of the first method
two separate processes are required, namely, measurements
of a degree of latitude on the arc of a meridian, and mea-
surements of a degree of longitude on different parallels.

Although seven years have now passed since I brought
forward the results of Bessel's important labours, in refer-
ence to the dimensions of our globe, in my General Delineation
of Nature, his work has not yet been supplanted by any one
of a more comprehensive character, or based upon more recent
measurement's of a degree. An important addition and great
improvements in this department of inquiry may, however,
be expected on the completion of the Russian geodetic mea-
surements, which are now nearly finished, and which, as they
extend almost from the North Cape to the Black Sea, will
afford a good basis of comparison for testing the accuracy of
the results of the Indian survey.

According to the determinations published by Bessel in
the year 1841, the mean value of the dimensions of our
planet was, according to a careful investigation7 of ten mea

early death has proved a severe loss to science, in PoggendorfFs Annalen
der Physilc und Chemie. Bd. xxxiii, 1834, s. 229—233.

7 The first accurate comparison of a large number of geodetic mea-
surements (including those made in the elevated plateau of Quito, two
East Indian measurements, together with the French, English, and
recent Lapland observations) was successfully effected by Walbeck, at
Abo, in 1819. He found the mean value for the earth's ellipticity to be
3oa 176l, and that of a meridian degree 57009.758 toises, or 324,628 feet.
Unfortunately his work, entitled De Forma et Magnitudine Telluris has
not been published in a complete form. Excited by the encouragement
of Gauss, Eduard Schmidt was led to repeat and correct his results in his
admirable Handbook of Mathematical Geography, in which he took into
account both the higher powers given for the ellipticity, and the lati-
tudes observed at the intermediate points, as well as the Hanoverian
measurements and those which had been extended as far as Formentera
by Biot and Arago. The results of this comparison have appeared in
three forms, after undergoing a gradual correction, namely, in Gauss's
JBestimmung der Breitenunterschiede von Gottingen undAltona 1828, s. 82 ;
in Eduard Schmidt's Lehrluchdcr Mathem. und Phys. Geographic, 1829,
Th. 1, s. 183, 194 — 199; and lastly in the preface to the latter work
(s. 5). The last result is, for a meridian degree 57008.655 toises, or
324,261 feet ; for the ellipticity, zWJ^^ra- Bessel's first work of 1 830 had
been immediately preceded by Airy's treatise on tioa Figure of the Earth,

THE SIZE OP THE EARTH. 15

Burements of degrees, as follows : — The semi-axis major of a
rotating spheroid, a form that approximates most closely to

in the Encyclopaedia Metropolitan a. Ed. of 1849, pp. 220 — 239. (Here
the semi-polar axis was given at 20.853,810 feet=3949.585 miles, the
semi-equatorial axis at 20,923,713 feet=3962.824 miles, the meridian
quadrant at 32,811,980 feet, and the ellipticity at ^g^ra)- The great
astronomer of Konigsberg was uninterruptedly engaged, from 1836 to
1842, in calculations regarding the figure of the earth, and as his earlier
works were emended by subsequent corrections, the admixture of re-
sults of investigations at different periods of time has, in many works,
proved a source of great confusion. In numbers, which from their very
nature are dependent on one another, this admixture is rendered still
more confusing from the erroneous reduction of measurements ; as, for
instance, toises, metres, English feet, and miles of 60 and 69 to the
equatorial degree ; and this is the more to be regretted since many
works, which have cost a very large amount of time and labour, are
thus rendered of much less value than they otherwise would be. In
the summer of 1837, Bessel published two treatises, one of which was
devoted to the consideration of the influence of the irregulai-ity of the
earth's figure upon geodetic measurements, and their comparison with
astronomical determinations, whilst the other gave the axes of the ob-
late spheroid, which seemed to correspond most closely to existing
measurements of meridian arcs (Schum. Astr. Nachr. bd. xiv, No.
329, s. 269, No. 333, s. 345). The results of his calculation were
3271953.854 toises for the semi-axis major; 3261072.900 toises for
the semi-axis minor ; and for the length of a mean meridian degree,
that is to say, for the ninetieth part of the earth's quadrant (vertically
to the equator), 57011.453 toises. An error of 68 toises, or 440.8 feet,
which was detected by Puissant, in the mode of calculation that
had been adopted, in 1808, by a Commission of the National Institute
for determining the distance of the parallels of Montjouy, near
Barcelona, and Mola in Formentera, led Bessel, in the year 1841,
to submit his previous calculations regarding the dimensions of the
earth to a new revision. (Schum. Astr. Nachr. Bd. xix, No. 438,
s. 97 — 116). This correction yielded for the length of the earth's
quadrant 5131179.81 toises, instead of 5130740 toises, which had
been obtained in accordance with the first determination of the metre ;
and for the mean length of a meridian degree, 57013.109 toises,
which is about 0.611 of a toise more than a meridian degree, at
45° lat. The numbers given in the text are the result of Bessel's latest
calculations. The length of the meridian quadrant, 5131180 toises,
with a mean error of 255.63 toises, is therefore=10000856 metres, which
would tnerefore give 40003423 metres, or 21563.92 geographical miles,
for the entire circumference of the earth. The difference between the
original assumption of the Commission des Poids et Mesures, according to
which the metre was the forty-millionth part of the earth's circumfer-
ence, amounts for the entire circumference to 3423 metres, or 1756 27
which is almost two geographical miles, or more accurately

1 6 COSMOS.

the irregular figure of our earth, was 3272077.14 toises, or
20,924,774 feet ; the semi-axis minor, 3261139.33 toises,
or 20,854.821 feet; the length of the earth's quadrant,
5131179.81 toises, or 32.811,799 feet ; the length of a mean
meridian degree, 57013.109 toises, or 364,596 feet ; the
length of a parallel degree at 0° latitude, and consequently
that of an equatorial degree, 57108.52 toises, or 365,186
feet ; the length of a parallel degree at 45°, 40449.371 toises,
or 258,657 feet ; the ellipticity of the earth, •?-$-$, TTT \ an(^
the length of a geographical mile, of which sixty go to an
equatorial degree, 951.8 toises, or 6086.5 feet.

The table (page 17) shows the increase of the length of the
meridian degree from the equator to the pole, as it has been
found from observations, and therefore modified by the local
disturbances of attraction

The determination of the figure of the earth by the mea-
surement of degrees of longitude on different parallels re-
quires very great accuracy in fixing the longitudes of different
places. Cassini de Thury and Lacaille employed, in 1740,
powder signals to determine a perpendicular line at the
meridian of Paris. In more recent times, the great trigono-
metrical survey of England has determined, by the help of
far better instruments and with greater accuracy, the lengths
of the arcs of parallels and the differences of the meridians
between Beachy Head and Dunnose, as well as between
Dover and Falmouth. These determinations were, however,
only made for differences of longitude of 1° 26' and 6C22' .8
By far the most considerable of these surveys is the one that
was carried on between the meridians of Marennes, on the
western coast of France, and JFiume. It extends over the
western chain of the Alps, and the plains of Milan and Padua,
in a direct distance of 15° 32' 27", and was executed under
the direction of Brousseaud and Largeteau, Plana and Car-

epeaking, 1.84. According to the earliest determinations, the length of
the metre was determined at 0.5130740 of a toise, while according to
Bessel's last determination it ought to be 0.5131180 of a toise. The
difference for the length of the metre is, therefore, 0.038 of a French
line. The metre has, therefore, been established by Bessel as equal
to 443.334 French lines, instead of 443.296, which is its present legal
value (Compare also, on this so-called natural standard, Faye, Lemons <U
Cosmographie, 1852, p. 93).

8 Airy, Figure of the Earth in the Encycl. Metrop. 1849, pp. 214—216.

THE SIZE OF THE EARTH.

17

2

gi

-* r-j o o o> o <M T-H io i— i o p cq CM o

CO <M 00 CO t^ O i— ' r-H i— < O -^ O *O C5 O*

^GOCCCOO^OCi O t-^005 CO OOr-H

lOiO^O^OiO^OtC^ -* CO CO <M CO ^^

i^COCO^OtOOOCO CO COCO^O CO COCO

COCQCOCOCOCOCOCO CO COCOCO CO COCO

11

05 o o as co" r^ co co"

I-H CO <M C^ id *O r- 1 CM

c o c co

COiO COCO iO4O
i— lOOOi-Hr-H(MCOC<l

T-HOO
i— » »O r-l CO rHCO

Geographical latitude
of the middle of the
measured arc.

Ob-^cdco'coidci CM O'-'O o" oo

i-H^^H <M(M CO<M

<M«D<M r-i OQCO
rH COCOf-l"*

(Mr-H

COCO

OiCO5<1 i-t
CO'—''—' COCO

l

ll

a

VOL. Y,

18 COSMOS.

lini, almost entirely under the so-called mean parallel of 45*.
The numerous pendulum experiments which have been con-
ducted in the neighbourhood of mountain chains, have con-
firmed in the most remarkable manner the previously-recog-
nised influences of those local attractions which were in-
ferred from the comparison of astronomical latitudes with
the results of geodetic measurements.9

In addition to the two secondary methods for the direct
measurement of a degree on meridian and parallel arcs, we
have still to refer to a purely astronomical determination of
the figure of the earth. This is based upon the action which
the earth exerts upon the motion of the moon, or in other
words upon the inequalities in lunar longitudes and latitudes.
Laplace, who was the first to discover the cause of these
inequalities, has also taught us their application by ingeni-
ously showing how they afford the great advantage which
individual measurements of a degree and pendulum experi-
ments are incapable of yielding, namely, that of showing in
one single result the mean figure of the earth.10 We would

9 Biot, Astr. Physique, t. ii, p. 482, and t. iii, p. 482. A very accu-
rate geodetical measurement, which is the more important from its
serving as a comparison of the levels of the Mediterranean and Atlantic,
has been made on the parallel of the chain of the Pyrenees by Cora-
boeuf, Delcros, and Peytier.

10 Cosmos, vol. i, p. 160. "It is very remarkable that an astronomer
without leaving his observatory, may merely by comparing his obser-
vations with analytical results, not only be enabled to determine with
exactness the size and degree of ellipticity 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. The moon may, therefore, by the observation of
its movements render appreciable to the higher departments of astro-
nomy, the ellipticity of the earth, as it taught the early astronomers
the rotundity of our earth by means of its eclipses" (Laplace, Expos, du
Syst. du M&iide, p. 230). We have already in Cosmos, vol. iv, pp. 481 —
532, made mention of an almost analogous optical method suggested by
Arago, and based upon the observation that the intensity of the ash-
coloured light, that is to say the terrestrial light in the moon, might
afford us some information in reference to the transparency of our
entire atmosphere. Compare also Airy in the Encycl. Metrop. pp. 189,
236, on the determination of the earth's ellipticity by means of the
motions of the moon, as well as at pp. 231 — 235. on the inferences which
he draws regarding the figure of the earth from precession and nutation.
According to Biot'a investigations, the latter determination would only

THE FIGURE OP THE EAKTH. 19

here again refer to the happy expression of the discoverer of
this method " that an astronomer without leaving his obser-
vatory may discover tue individual form of the earth in
which he dwells, from the motion of one of the heavenly
bodies." After his last revision of the inequalities in the
longitude and latitude of our satellite, and by the aid of
several thousand observations of Burg, Bouvard, and Burck-
hardt,11 Laplace found by means of his lunar method a
compression amounting to ¥^g-, which is very nearly equal to
that yielded by the measurements of a degree of latitude

(2^9)-

The vibrations of the pendulum yield a third means of de-
termining the figure of the earth (or in other words the
relation of the major to the minor axis, on the supposition of
our planet being of a spheroidal form), by the elucidation of
the law according to which gravity increases from the equator
towards the pole. The Arabian astronomers, and more es-
pecially Ebn-Junis, at the close of the tenth century, and
during the brilliant epoch of the Abbassidian Califs13, first
employed these vibrations for the determination of time, and
after a neglect of six hundred years the same method was
again adopted by Galileo, and Father Riccioli at Bologna.13
The pendulum in conjunction with a system of wheels used
to regulate the clocks (which were first employed in the
imperfect experiments of Sanctorius at Padua in 1612, and
then in the more perfect observations of Huygens in 1656),
gave the first material proof of the different intensity of gravity
at different latitudes in Richer's comparison of the beats of
the same astronomical clock at Paris and Cayenne, in 1672.
Picard was indeed engaged in the equipment of this im-
portant voyage, but he does not on that account assume to
himself the merit of its first suggestion. Richer left Paris

give, for the earth's ellipticity, limiting and widely differing values
(•5fT and -gfa). Astron. Physique, 3eme ed. t. ii, 1844, p. 463.

11 Laplace, Mecanique Celeste, e"d. de 1846, t. v. pp. 16, 53.

l- Cosmos, vol. i, p. 158. Edward Bernard, an Englishman, was the first
who recognised the application of the isochronism of pendulum-oscil-
lations in the writings of the Arabian astronomers. (See his letter, dated
Oxford. April, 1683, and addressed to Dr. Robert Huntington, in
Dublin. Philos. Transac. vol. xii, p. 567.)

13 Frgret de V Etude de la Philosophic Ancienne in the Mem. de I'Acad,
des Inscr. t. xviii Q753), p. 100.

C2

20 COSMOS.

in October, 1671, and Picard in the description of his mea-
surement of a degree of latitude, which appeared in the same
year u merely refers to " a conjecture which was advanced

14 Picard, Mtsure de la Terre, 1671, Art. 4. It is scarcely probabla
that the conjecture which was advanced in the Paris Academy even
before the year 1671, to the effect that the intensity of gravity varies
with the latitude (Lalande, Astronomic, t. iii, p. 20 § 2668) should have
been made by the illustrious Huygens, who had certainly presented
his Discours sur la Cause de la Gravite to the Academy in the course
of the year 1669. There in no mention made in this treatise of the
shortening of the seconds-pendulum, which was being observed by
Richer at Cayenne, although a reference to it occurs in the supple-
ments to this work, (one of which must have been completed after the
publication of Newton's Principia, and consequently later than 1687).
Huygens writes as follows: — "Maxima pars hujus libelli scripta est,
cum Lutetise degerem (to 1681) ad eum usque locum, ubi de altera-
tione, quae pendulis accidit e motu Terrse." See also the explanation
which I have given in Cosmos, vol. ii, p. 736. The observations made
by Richer at. Cayenne were not published until 1679, as I have already
observed in the text, and therefore not until fully six years after his
return, and what is more remarkable, the annals of the Academic des
Inscriptions contain no notice during this long period of Richer's im-
portant double observations of the pendulum clock and of the simple
seconds-pendulum. We do not know the time when Newton first
became acquainted with Richer's results, although his own earliest
theoretical speculations regarding the figure of the earth date farther
back than the year 1665. It would appear that Newton did not be-
come acquainted until 1682 with Picard's geodetic measurement, which
had been published in 1671, and even then " he accidentally heard of it
at a meeting of the Royal Society, which he was attending." His know-
ledge of this fact as Sir David Brewster has shown (Memoirs of Sir I.
Neviton, vol. i, p. 291), exerted a very important influence on his deter-
mination of the earth's diameter, and of the relation which the fall of
a body upon our planet bears to the force which retains the moon in
its orbit. Newton's views may have been similarly influenced by the
knowledge of the spheroidal form of Jupiter which had been ascertained
by Cassini prior to 1666, but was first described in 1691 in the Memoires
de i' Academic des Sciences, t. ii, p. 108. Could Newton have learnt
anything of a much earlier publication, of which some of the sheets
were seen by Lalaude in the possession of Maraldi? (Compare
Laiande, Astr. t. iii. p. 335, § 3345, with Brewster, Memoirs of Sir /.
Newton, vol. i, p. 322, and Cosmos, vol. i, p. 156.) Amid the simultan-
eous labours of Newton, Huygens, Picard, and Cassini, it is often very
difficult to arrive, with any certainty, at a just appreciation of the diffu-
sion of scientific knowledge, owing to the tardiness with which men
at that day made known the result of their observations, the pub-
lication of which, was moreover frequently delayed by accidental cir*
cu instances.

THE FIGURE OF THE EAETH. 21

by one of the members, at a meeting of the Academy, ac-
cording to which the weight of a body must be less at the
equator than at the pole, in consequence of the rotation of
the earth." He adds doubtfully, that although it would
appear from certain experiments made in London, Lyons,
and Bologna, as if the seconds-pendulum must be shortened
the nearer we approach to the equator; yet on the other
hand he was not sufficiently convinced of the accuracy
of the measurements adduced, because at the Hague, not-
withstanding its more northern latitude, the pendulum
lengths were found to be precisely the same as at Paris.
The periods at which Newton first became acquainted with
the important pendulum results that had been obtained by
Richer as early as 1672, although they were not printed
until 1679, and at which he first heard of the discovery that
had been made by C.assini, before the year 1666, of the' com-
pression of Jupiter's disc, have unfortunately not been re-
corded with the same exactness, as the fact of his very tardy
acquaintance with Picard's measurement of a degree. In an
age so remarkable for the successful emulation that distinguished
the cultivators of science, and when theoretical views led to
the prosecution. of observations, which by their results re-
acted in their turn upon theory, it is of great interest to the
history of the mathematical establishment of physical as-
tronomy, that individual epochs should be determined with
accuracy.

Although direct measurements of meridian and parallel
degrees (the former especially in the cast? of the French
measurement of a degree15 between the latitudes 44° 42'
and 47° 30', and the latter by the comparison of points lying
to the east and west of the Italian and Maritime Alps),1*
exhibit great deviations from the mean ellipsoidal figure of
the earth, the variations in the amount of ellipticity given
by pendulum lengths (taken at different geographical points
and in different groups) are very much more striking. The
determination of the figure of the earth obtained from the

15 Delambre, East du Syst. Mttriqiw, t. iii, p. 548.

16 Cosmos, vol. i, p. 159. Plana, Operations G6od6siques et Astrono-
miqucs pour la Mesure dun Arc du ParalUle Moyen, t. ii, p. 847;
Carlini in the £/emeridi Astronomiche di Milano per Vanno 1842,
p. 57.

22 COSMOS.

increase or decrease of gravity (intensity of local attraction),
assumes that gravity at the surface of our rotating spheroid
must have remained the same as it was at the time of our
earth's consolidation from a fluid state, and that no later
alterations can have taken place in its density.17 Not-
withstanding the great improvements which have been made
in the instruments and methods of measurement by Borda,
Kater, and Bessel, there are at present in both hemispheres,
from Spitzbergen in 79° 50' N.L., to the Falkland Islands, in
51° 35' S.L., where Freycinet, Duperrey, and Sir James Ross
successively made their observations, only from 65 to 70
irregularly scattered points,18 at which the length of the
simple pendulum has been determined with as much accu-
racy as the position of the place in respect to its latitude,
longitude, and elevation above the level of the sea.

The pendulum experiments made by the French astrono-
mers on the measured part of a meridian arc, and the obser-
vations of Captain Kater in the trigonometrical survey of
Great Britain concurred, in showing that the results do not
individually admit of being referred to a variation of gravity
proportional to the square of the sine of the latitude. On this
account the English Government determined, at the sugges-
tion of the Vice-President of the Royal Society, Davies
Gilbert, to fit out a scientific expedition, which was en-
trusted to my friend Edward Sabine, who had accompanied
Captain Parry on his first polar voyage in the capacity of
astronomer. In the course of this voyage, which was con-
tinued through the years 1822 and 1823, he coasted along

17 Compare Biot, Astronomic Physique, t. ii, 1844, p. 464, with Cosmos,
vol. i, p. 160, and vol. iv, p. 427, where I have considered the difficulties
presented by a comparison of the periods of rotation of planets, and
their observed compression. Schubert (Astron. Th. iii, s. 316) has
also drawn attention to this difficulty, and Bessel in his treatise On
Mass and Weight says expressly, that the supposition of the invariability
of gravity at any one point of observation has been rendered somewhat
uncertain by the recent experiments made on the slow upheaval of large
portions of the earth's surface.

18 Airy in his admirable treatise on the Figure of the Earth (Encycl.
Metropol. 1849, p. 229) reckoned fifty different stations where trust-
worthy results had been obtained up to the year 1830, and fourteen
others, (those of Bouguer, Legentil, Lacaille, Maupertuis and La
Croyere), which however do not bear comparison with the former iu
point of accuracy.

THE FIGURE OF THE EARTH. 23

the western shores of Africa, from Sierra Leone to the Is-
land of St. Thomas, near the Equator, then by Ascension to
South America, from Bahia to the mouth of the Orinoco, on
his way to the West Indies and the New England States,
after which he penetrated into the Arctic regions as far as
Spitzbergen, and a hitherto unexplored and ice-bound portion
of East Greenland (74° 32'). This brilliant and ably con-
ducted expedition had the advantage of being mainly
directed to one sole object of investigation, and of embracing
points which are separated from one another by 93° of
latitude.

The field of observation in the French expedition for the
measurements of degrees was more remote from the equinoc-
tial and arctic zones ; but it had the great advantage of
presenting a linear series of points of observation, and of
affording direct means of comparison with the partial curvature
of the arcs obtained by geodetico-astronomical observations.
Biot, in 1824, carried the line of pendulum measurements
from Formentera (38° 39' 56") where he had already made
observations conjointly with Arago and Chaix, as far as
Unst, the most northerly of the Shetland Islands (60° 45'
25"), and with Mathieu he extended it to the parallels
of Bordeaux, Figeac, and Padua, as far as Fiume.19 These
pendulum results, when compared with those of Sabine,
certainly give -%^-Q for the compression of the whole northern
quadrant, but when separated into two halves, they yield
a still more varying result, giving T^-^ from the equator to
45°, and -^^ from 45° to the pole.20 It has been shown

19 Biot and Arago, Recueild'Observ. Geodesiques et Astronomiques, 1821,
pp. 526—540, and Biot, Traite d'Astr. Physique, t. ii, 1844, pp. 465—
473.

20 Op. cit. p. 488. Sabine (Super, for determining the variation in the
length of the Pendulum, vibrating Seconds, 1825, p. 352) finds ^irW from
all the thirteen stations of his pendulum expedition, notwithstanding
their great distances from one another in the northern hemisphere ;
and from these, increased by all the pendulum stations of the British
survey and of the French geodetic measurement from Formentera to
Dunkirk, comprising therefore in all a comparison of twenty -five points of
observation he again found TffW- ^ *8 st^l more striking, as was already
observed by Admiral Llitke, that far to the west of the Atlantic region
in the meridians of Petropawlowski and New Archangel, the pendulum
lengths yield a much greater ellipticity, namely •^T. As the previously
applied theory of the influence of the air surrounding the pendulum

24 COSMOS.

in many instances, and in both hemispheres, that there is an
appreciable influence exerted by surrroimding denser rocks,
(basalt, greenstone, diorite, and melaphyre, in opposition to
specifically lighter secondary and tertiary formations,) in the
same manner as volcanic islands21 influence gravity and
augment its intensity. Many of the anomalies which pre-
sented themselves in these observations do not, however,
admit of being explained by any visible geological characters
of the soil.

For the southern hemisphere we possess a small number
of admirable, but very widely diffused observations made by
Freycinet, Duperrey, Fallows, Liifcke, Brisbane and Bumker.
These observations have confirmed a fact which had been
strikingly demonstrated in the northern hemisphere, namely,
that the intensity of gravity is not the same for all places
having the same latitude, and that the increase of gravity
from the equator towards the poles appears to be subjected
to different laws under different meridians. Although the
pendulum measurements made by Lacaille at the Cape of
Good Hope, and those conducted in the Spanish circumnavi-
gating expedition by Malaspina, may have led to the belief
that the southern hemisphere is in general much more com-
pressed than the northern, comparisons made between the
Falkland Islands and New Holland on the one hand,

led to an error in the calculation, and had rendered a correction neces-
sary as early as 1786, (when a somewhat obscure one was given by tha
Chevalier de Buat,) on account of the difference in the loss of weight
of solid bodies, when they are either at rest in a fluid, or impelled in a
vibratory motion, Bessel with his usual analytical clearness laid down
the following axiom in his Untersuchungen iiber die Lange des einfachen
Secundertpendels, s. 32, 63, 126 — 129. "When a body is moving in a
fluid (the atmosphere), the latter belongs with it to the moved system,
and the moving force must be distributed not only over the particles
of the solid moved body, but also over all the moved particles of the
fluid." On the experiments of Sabine and Baily, which originated in
Bessel's practically important pendulum correction (reduction to a
vacuum), see JohnHerschelin the Memoir of Francis Baily, 1845, pp.
17—21.

21 Cosmos, vol. i, p. 159. Compare, for the phenomena occurring in
islands, Sabine Pend. Exper. 1825, p. 237, and Liitke, Obs. du Pendule
invariable, exScuUes de 1826 — 1829, p. 241. This work contains a
remarkable table, p. 239, on the nature of the rocks occurring at 16
pendulum stations, from Spitsbergen (79° 50' N. Lat.) to Valparaiso
(33° 2' S. Lat.).

THE FIGURE OF THE EARTH. 25

and New York, Dunkirk, and Barcelona on the other,
have, however, by their more exact results shown that
the contrary is the case, as I have already elsewhere in-
dicated.22

From the above data, it follows that the pendulum (al-
though it is by no means an unimportant instrument in
geognostic observations, being as it were a sort of plummet
cast into the deep and unseen strata of the earth) does not
determine the form of our planet with the same exactitude
is the measurement of a degree, or the movements of our
satellite. The concentric, elliptical, and individually homo-
geneous strata, which increase in density according to certain
functions of distance from the surface towards the centre of
the earth, may give rise to local fluctuations in the intensity
of gravity at individual points of the earth's surface, which
differ according to the character, position, and density of the
several points. If the conditions which produce these devi-
ations are much more recent than the consolidation of the

22 Cosmos, vol. i, p. 161. Eduard Schmidt (Mathem. und Phys. Geo-
graphic, Th. i, s. 394), has separated from a large number of the pen-
dulum observations which were made on board the corvettes Descubierta
and Atrevida, under the command of Malaspina, those thirteen stations
which belong to the southern hemisphere, from which he obtained a
mean compression of ^TO-'ST- Mathieu obtained ^g-W fr°m a compa-
rison of Lacaille's observations at the Cape of Good Hope and the Isle
of France with Paris, but the instruments of measurement used at that
day did not afford the same certainty as we now obtain by the appli-
ances of Borda and Kater, and the more modern methods of observa-
tion. The present would seem a fitting place to notice the beautiful
experiments of Foucault, which afford so high a proof of the ingenuity
of the inventor, and by which we obtain ocular evidence of the rotation
of the earth on its axis by means of the pendulum, whose plane of
vibration slowly rotates from east to west. (Comptes rendus de I'Acad.
des Sc., Seance du 3 Fevrier, 1851, t. xxxii, p. 135). Experiments for
noticing the deviation towards the east in observations of falling
bodies, dropped from church towers or into mines, as suggested by
Benzenberg and Reich, require a very great height, whilst Foucault's
apparatus makes the effects of the earth's rotation perceptible with a
pendulum only six feet long. We must not confound the phenomena
. which may be explained by rotation (as, for instance, Richer's clock
experiments at Cayenne, diurnal aberration, the deviation of projectiles,
trade winds, etc.), with those that may at any time be produced by
Foucault's apparatus, .and of which the members of the Academia del
Cimento appear to have had some idea, although they did not farther
develope it ^A.utinori, in the Comptes rendus, t. xxxii, p. 635).

*O COSMOS.

outer crust, the figure of the surface cannot be assumed to
be locally modified by the internal motion of the fused
masses. The difference of the results of pendulum measure-
ments is however much too great to be ascribed at the pre-
sent day to errors of observation. Even where a coinci-
dence in the results, or an obvious regularity has been dis-
covered by the various grouping and combination of the
points of observation, the pendulum always gives a greater
ellipticity (varying between the limits -^y and -3 §~o) than
could have been deduced from the measurements of a degree.
If we take the ellipticity which, in accordance with
Bessel's last determination, is now generally adopted,
namely, ^^Jy^, we shall find that the bulging23 at the

23 In Grecian antiquity two regions of the earth were designated as
being characterised, in accordance with the prevalent opinions of the
time, by remarkable protuberances of the surface, namely, the high
north of Asia and the land lying under the equator. " The high and
naked Scythian plains," says Hippocrates (de Acre et Aquis § xix, p. 72,
Littre"), "without being crowned by mountains stretch far upward to
the meridian of the Bear." A similar opinion had previously been
ascribed to Empedocles (Plut. de Plac. Philos. ii, 8). Aristotle (Meteor.
i, 1 a 1 5, p. 66, Ideler) says that the older meteorologists, according to
whose opinions the sun " did not go under the earth, but passed round
it," considered that the protuberances of the earth towards the north
were the cause of the disappearance of the sun, or of the production of
night. And in the compilation of the Problems (xxvi, 15, page 941,
Bekker), the cold of the north wind was ascribed to the elevation of
the soil in this region of the earth, and in all these passages there is
no reference to mountains, but merely to a bulging of the earth into
elevated plateaux. I have already elsewhere shown (Asie Centrale, t. i,
p. 58) that Strabo, who alone makes use of the very characteristic word
opoTridia, says that the difference of climate which arises from geogra-
phical position must everywhere be distinguished from that which we
ascribe to elevation above the sea, in Armenia (xi, p. 522, Casaub.), in
Lycaonia, which is inhabited by wild assea (xii, p. 568), and in Upper
India, in the auriferous country of the Derdi (xv, p. 706). " Even in
southern parts of the world," says the geographer of Amasia, " every
high district, if it be also a plain, is cold " (ii, p. 73). Eratosthenes
and Polybius ascribe the very moderate temperature which prevails
under the equator not only to the more rapid transit of the sun
(Geminus, JElem. Astron. c. 13, Cleom. Cycl. Theor., 1, 6), but more espe-
cially to the bulging of the earth (See my Examen Grit, de la Geogr.
t. iii, pp. 150 — 152). Both maintain, according to the testimony of
Strabo (ii, p. 97), " that the district lying immediately below the equator
is the highest, on which account much rain falls there, in consequence
of the very large accumulation of northern clouds at the period when

THE FIGURE OP THE EARTH. 27

equator amounts to about 645,457 feet ; about 11-J-, or more
accurately, 11.492 geographical miles. As a comparison has

those winds prevail, which change with the season of the year." Of
these two opinions regarding the elevation of the land in Northern
Asia, (the Scythian Europe of Herodotus) and in the equatorial zone, the
former of the two, with the pertinacity characteristic of error, has kept
its ground for nearly two thousand years, and has given occasion to the
geological myth of an uninterrupted plateau in the Tartar district
lying to the north of the Himalayas, whilst the other opinion could only
be justified in reference to a portion of Asia, lying beyond the tropical
zone, and consequently applies only to the colossal, " elevated or
mountain plateau, Meru," which is celebrated in the most ancient and
noblest memorials of Indian poetry. (See "Wilson's Diet. Sanscrit and
English, 1832, p. 674, where the word Meru is explained to signify an
elevated plateau). I have thought it necessary to enter thus circum-
stantially into this question, in order that I might refute the hypothesis
of the intellectual Freret, who, without indicating any passages from
Greek writers, and merely alluding to one which seemed to treat of
tropical rain, interprets the opinion advanced regarding bulgings of the
soil as having reference to compression or elongation at the poles. In
the Mem. de I'Acad. des Inscriptions, t. xviii, 1753, p. 112, FreVet expresses
himself as follows :— " To explain the rains which prevailed in those
equinoctial regions, which the conquests of Alexander first made known,
it was supposed that there were currents which drove the clouds from
the poles towards the equator, where, in default of mountains to stop
their progress, they were arrested by the general elevation of the soil,
whose surface at the equator is farther removed from the centre than
under the poles. Some physicists have ascribed to the globe the figure
of a spheroid, which bulges at the equator and is flattened towards the
poles, while on the contrary, in the opinion of those of the ancients who
believed that the earth was elongated towards the poles, the polar
regions are farther removed than the equatorial zone from the centre
of the earth." I can find no evidence in the works of the ancients to
justify these assertions. In the third section of the first book of Strabo
(page 48, Casaub.), it is expressly stated that, " after Eratosthenes has
observed that the whole earth is spherical, although not like a sphere
that has been made by a turning-lathe (an expression that is borrowed
from Herodotus, iv. 36), and exhibits many deviations from this form,
he adduces numerous modifications of shape which have been produced
by the action of water and fire, by earthquakes, subterranean currents
of wind (elastic vapours?), and other causes of the same kind, which,
however, are not given in the order of their occurrence, for the rotun-
dity of the entire earth results from the co-ordination of the whole, such
modifications in no degree affecting the general form of our earth, the
lesser vanishing in the greater." Subsequently we read, also in Gros-
kurd's admirable translation, " that the earth, together with the sea, ia
spherical, the two constituting one and the same surface. The projec-
tion of the laud, which is inconsiderable and may remain unnoticed ia

28 COSMOS.

very frequently been made from the earliest times of astro-
nomical inquiry between this swelling or convex elevation
of the earth's surface and carefully measured mountain
masses, I will select as objects of comparison the highest of
the known peaks of the Himalayas, namely, that of Kin-
tschindjinga, which was fixed by Colonel Waugh at 28,174
feet, and that portion of the elevated plateau of Thibet
which is nearest to the sacred lakes of Rakas-Tal and Man-
assarova, and which, according to Lieutenant Henry Strachey,
is situated at the mean height of 15,347 feet. The bulg-
ing of our planet at the equatorial zone is therefore not

lost in such magnitudes, so that in these cases we are unable to deter-
mine its spherical form with the same accuracy as in the case of a sphere
made by a turning-lathe, or as well as the sculptor, who judges from
his conceptions of form, for here we are obliged to determine by phy-
sical and less delicate perception " (Strabo, ii, p. 112). "The world ia
at once a work of nature and of providence, — a work of nature inasmuch
as all things tend towards one point, the centre of the whole, round
which they group themselves, the less dense element (water) containing
the denser (earth)." (Strabo, xvii, p. 809). Wherever we find the figure
of the earth described by the Greeks, it is compared (Cleom. Cycl. Theor. i,
8, p. 51) with a flat or centrally depressed disc, a cylinder (Anaximander),
a cube or pyramid, and lastly we find it generally held to be a sphere not*
withstanding the long contest of the Epicureans, who denied the ten-
dency of attraction towards the centre. The idea of compression does not
seem to have presented itself to their imagination. The elongated earth
of Democritus was only the disc of Thales lengthened in one direction.
The drum-like form, TO cfxrjua rv^Travoaofg, which seems more especially
to have emanated from Leucippus (Pint, de Plac. Philos. iii, 10; Galen.
Hist. Phil, cap. 21; Aristotle, de Ccelo, ii, 13 page, 293 Bekker), appears
to have been founded upon the idea of a hemisphere with a flat basis,
which probably represented the equator, whilst the curvature was re-
garded as the oiKovukvr}. A passage in Pliny, regarding Pearls (xi,
54), elucidates this form, whilst Aristotle merely compares the segments
of the sphere with the drum (Meteorol. ii, 5, a 10, Ideler, t. i, p. 563), as
we also find from the commentary of Olympiodorus (Ideler, t. i, p. 301).
I have here purposely avoided referring to two passages which are well
known to me in Agathemerus (de Geographia, lib. i, cap. 1, p. 2, Hudson)
and in Eusebius (Evangel. Prceparat. t. iv, p. 125, ed. Gaisford, 1843),
because they prove with what inaccuracy later writers have often
ascribed to the ancients views which were totally foreign to them.
According to these versions, " Eudoxus gave for the length and breadth
of the earth's disc values which stood in relation to one another as
1 to 2; the same is said in reference to Dictearchus, the pupil of Aris-
totle, who, however, advanced his own special proofs of the spherical
form of the earth (Marcian, Capella, lib. vi, p. 192). Hipparchus re-
garded tha earth as rpa7rt£oa<^£, and Thales held it to be a sphere!"

THE FIGURE OF THE EARTH. 29

quite three times as great as the elevation of the highest of
our mountains above the sea's level, but it is almost five
times as great as that of the eastern plateau of Thibet.

We ought here to observe that the results of the earth's
compression, which have been obtained by mere measure-
ments of a degree, or by combinations of the former with
pendulum measurements, show far less 24 considerable differ-
ences in the amount of the equinoctial bulging than we
should have been disposed at first sight to conclude from the
fractional numbers. The difference of the polar compres-
sions (¥{-Q and -2^-0) amounts to only about 7000 feet in
the difference of the major and minor axes, basing the calcu-
lation on both extreme numerical limits; and this is not
twice the elevation of the small mountains of the Brocken
and of Vesuvius ; the difference being only about one- tenth

24 It has often seemed to me as if the amount of the compression of
the earth was regarded as somewhat doubtful merely from our wish
to attain an unnecessary degree of accwacy. If we take the values of
the compression at ^, 7-Lj, ^t ^, we find that the difference of
both radii is equal to 10,554, 10,905, 11,281, 11,684 toises, or 67,488,
69,554, 73,137, 74,714 feet. The fluctuation of 30 units in the denomi-
nator produces only a fluctuation of 1,130 toises or 7,126 feet in the
polar radius, an amount which, when compared with the visible in-
equalities of the earthis surface appears so very inconsiderable, that I
am often surprised to find that the experiments coincide within such
closely approximating limits. Individual observations scattered over
wide surfaces will indeed teach vis little more than what we already
know, but it would be of considerable importance to connect together
all the measurements that have been made over the entire surface of
Europe, including in this calculation all astronomically determined
points." (Bessel, in a letter addressed to myself, December, 1828.) Even
if this plan were carried out, we should then only know the form of
that portion of the earth, which may be regarded as a peninsular pro-
jection, extending westward, about sixty-six and a half degrees from the
great Asiatic Continent. The steppes of Northern Asia, even the mid-
dle Kirghis steppe, a considerable portion of which I have myself seen,
are often interspersed with hills, and in respect to uninterrupted
levels, cannot be compared with the Pampas of Buenos Ayres, or the
Llanos of Venezuela. The latter, which are far removed from all
mountain chains and consist immediately below the surface of secon-
dary and tertiary strata, having a very uniform and low degree of den-
sity, might by differences in the results of pendulum vibrations, yield
veiy decisive conclusions in reference to the local constitution cf the
deep internal strata of the earth. — Compare my Views of Naturt,
pp. 2—8, 29—32.

30 COSMOS.

of the bulging which would be yielded by a polar compres-
sion of -

As soon as it had been ascertained by more accurate mea-
surements of a degree, made at very different latitudes, that
the earth could not be uniformly dense in its interior, (because
the results showed that the compression was very much
less than had been assumed by Newton (-^o"), an(^ much
greater than was supposed by Huygens (-5^), who con-
sidered that all forces of attraction were combined in the
centre of the earth,) the connection between the amount
of compression and the law of density in the interior of our
earth necessarily became a very important object of ana-
lytical calculation. Theoretical speculations regarding gravity
very early led to the consideration of the attraction of large
mountain masses, which rise freely and precipitously into
the atmosphere from the dried surface of our planet. New-
ton, in his Treatise of the System of the World in a Popular
Way, 1728, endeavoured to determine what amount of
deviation from the perpendicular direction the pendulum
would experience from a mountain 2,665 feet in height and
5,330 feet in diameter. This consideration very probably
gave occasion to the unsatisfactory experiments, which were
made by Bouguer on Chimborazo, 25 by Maskelyne and

25 Bouguer who had been induced by La Condamine to institute
experiments on the deviation of the plummet near the mountain of
Chimborazo, does not allude in his Figure de la Terre, pp. 364 — 394
to Newton's proposition. Unfortunately the most skilful of the two
travellers did not observe on the east and western sides of the
colossal mountain, having limited his experiments (December, 1738) to
two stations lying on the same side of Chimborazo, first in a south-
erly direction 61° 30' West, about 4,572 toises or 29,326 feet from
the centre of the mountain, and then to the South 16° West (distance
1,753 toises or 11,210 feet). The first of these stations lay in a district
with which I am well acquainted, and probably at the same elevation
as the small alpine lake of Yana-cocha, and the other in the pumice-stone
plain of the Arenal (La Condamine, Voyage d I'Equateur, pp. 68 — 70).
The deviation yielded by the altitudes of the stars, was, contrary to all
expectation, only 7. "5 which was ascribed by the observers themselves
to the difficulty of making observations so immediately in the vicinity
of the limit of perpetual snow, to the want of accuracy in their instru-
ments, and above all to the great cavities which were conjectured to
exist within this colossal trachytic mountain. I have already expressed
many doubts, based xipon geological grounds, as to this assumption of
very large cavities, and of the very inconsiderable mass of the tra-

THE FIGURE OF THE EARTH. 31

Hutton on Shehallien, near Blair- Athol, in Perthshire ; to
the comparison of pendulum lengths on a plain lying at an
elevation of 6000 feet and at the level of the sea (as for
instance Carlini's observations at the Hospice of Mont Cenis,
and Biot and Mathieu's at Bordeaux); and lastly to the deli-
cate and thoroughly decisive experiments undertaken in 1837
by Reich and Bailey with the ingeniously constructed torsion-
balance which was invented by John Mitchell and subse-
quently given to Cavendish by Wollaston.26 The three
modes of determining the density of our planet (by vicinity
to a mountain mags, elevation of a mountainous plateau, and
the balance) have already been so circumstantially detailed
in a former part of the Cosmos (vol. i, p. 158), that it only
remains for us to notice the experiments given in Reich's
new treatise, and prosecuted by that indefatigable observer
during the interval between the years 1847 and 1850.27

chytic dome of Chimborazo. South-south-east of this mountain, near
the Indian village of Calpi, lies the volcanic cone of Yana-urcu, which
I carefully investigated in concert with Bonpland, and which is cer-
tainly of more recent origin then the elevation of the great dome-
shaped trachytic mountain, in which neither I nor Boussingault could
discover anything analogous to a crater. See the Ascent of Chimborazo
in my Rhine Schriften, Bd. i, s. 138.

26 Baily, Exper. with the Torsion Rod for determining the mean density
of the earth, 1843, p. 6; John Herschel, Memoir of Francis Baily,
1845, p. 24.

07 Reich, Neue Versuchemit der Drehwage, in iheAlkandl. dermathem.
physischen Classe der Ron. Sdchsischen Gesellschaft der Wissenschaften zu
Leipzig, 1852, Bd. i, s. 405, 418. The most recent experiments of my
respected friend Professor Reich, approximate somewhat more closely
to the results given in Baily's admirable work. I have obtained the
mean 5.5772 from the whole series of experiments: (a) with the tin
ball and the longer thicker copper wire, the result was 5.5712, with a
probable error of 0.0113; (b) with the tin ball, and with the shorter
thinner copper wire, as well as with the tin ball and the bi-filar iron
wire, 5.5832, with a probable error of 0.0149. Taking this error into
account, the mean in (a) and (b) is 5.5756. The result obtained by Baily,
and which was certainly deduced from a larger number of experiments
(5.660), might indeed give us a somewhat higher density, as it obviously
rose in proportion to the greater lightness of the balls that were used
in the experiments, which were either of glass or ivory. (Reich in
Poggend. Annalen, Bd. Ixxxv, s. 190. Compare also Whitehead Hearn
in the Philos. Transact, for 1847, pp. 217—229.) The motion of the
torsion balance was observed by Baily by means of the reflection of a
acale obtained from a mirror, which was attached to the middle of th«

32 COSMOS.

The whole may in accordance with the present state of our
knowledge be arranged in the following manner : —

Sliehallien, according to the mean of the maximum
4.867 and the minimum 4.559, as found by Play-
fair 4.713

Mont Cenis, observations of Carlini, with the cor-
rection of Giulio, 4.950

The torsion-balance, Cavendish (according to Baily's

calculation) . 5.448

Reich, 1838 5.440

Badly, 1842 5.660

Reich, 1847—1850 5.577

The mean of the two last results gives 5. 62 for the density
of the earth (taking that of water as 1), and consequently
much more than the densest finely granular basalt, which
according to the numerous experiments of Leonhard varies
from 2.95 to 3.67, and more than that of magnetic iron (4,9
-to 5.2), and not much less than that of the native arsenic of
Marienberg or Joachimsthal. We have already elsewhere
observed (Cosmos, vol, i, p. 159) that from the great distribu-
tion of secondary and tertiary formations, and of those up-
heaved strata which constitute the visible continental part of
our earth's surface (the plutonic and volcanic upheavals
being scattered in the form of islands over a small area of
space), the solid portion of the upper part of the earth's crust
possesses a density scarcely reaching from 2.4 to 2.6. If we
assume with Rigaud that the relation of the solid to the
fluid oceanic surface of our globe is as 10 : 27, and if further
we consider that the latter has been found by experiments
with the sounding lead to extend to a depth of 27,700 feet,
the whole density of the upper strata, which underlie the dry
and oceanic surfaces, scarcely equals 1.5. The distinguished
geometrician Plana has correctly observed that the author of
the jftlecanique Celeste was in error, when he ascribed to the
upper stratum of the earth a density equal to that of granite,

balance, a method that had been first suggested by Reich, and was
employed by Gauss in his magnetic observations. The use of such a
mirror, which is of great importance from the exactness with which
the scale may be read off, was proposed by Poggendorfi' as early as the
year 1826 (Annakn der Physik. Bd. vii, s. 121)

THE DENSITY OF THE EARTH. 33

which, moreover, he estimated somewhat highly at 3, which
would give him 10.047 for the density of the centre of the
earth.2* This density would, according to Plana, be 16.27 if
we assume that of the upper strata = 1.83, which differs
but slightly from the total density of 1 .5 or 1 .6 of the earth's
crust. The vertical pendulum, no less than the horizon ;al
torsion balance, may certainly be designated as a geognostic
instrument; but the geology of the inaccessible parts of the
interior of our globe is, like the astrognosy of the unillumi-
nated celestial bodies, to be received with considerable cau-

28 Laplace, Mccanigue Celeste, <k1. de 1846, t. v, p. 57. The mean
specific weight of granite cannot be set down at more than 2.7, since
the bi-axial white potash-mica, and green uni-axial magnesia-mica range
from 2.85 to 3.1, whilst the other constituents of this rock, namely
quartz and felspar are 2.56 and 2.65. Even oligoclase is only 2.68. If
hornblende rises as high as 3.17, syenite, in which felspar always pre-
dominates, never rises above 2.8. As argillaceous schist varies from
2.69 to 2.78, while pure dolomite, lying below limestone, equals only
2.88, chalk 2.72, and gypsum and rocksalt only 2.3, I consider that
the density of those continental parts of the crust of our earth, which
are appreciable to us should be placed at 2.6 rather than at 2.4. La-
place, on the supposition that the earth's density increases in arith-
metical progression from the surface towards the centre, and on the
assumption (which is assuredly erroneous) that the density of the
upper stratum is equal to 3, has found 4.7647 for the mean density of
the- whole earth, which deviates very considerably from the results ob-
tained by Reich (5.577) and by Baily (5.660); this deviation being much
greater than could be accounted for by the probable error of observa-
tion. In a recent discussion on the hypothesis of Laplace, which will
soon form a very interesting paper in Schumacher's A str. Nachrichten,
Plana has arrived at the result that, by a different method of treating
this hypothesis, Reich's mean density of the earth, and the density of
the dry and oceanic superficial strata, which I estimated at 1.6, aa
well as the ellipticity, within the limits that seem probable for the latter
value, may be very closely approximated to. " If the compressibility
of the substances of which the earth is formed," writes the Turin geo-
metrician, " has given rise to regular strata, nearly elliptical in form,
and having a density which increases from the surface towards the
centre, we may be allowed to suppose that these strata, in the act of
becoming consolidated, have experienced modifications, which, although
they are actually very small, are nevertheless large enough to preclude
the possibility of our deducing, with all the precision that we could
desire, the condition of the solid earth from its prior state of fluidity.
This reflection has made me attach the greater weight to the first
hypothesis advanced by the author of the Mecanique Celeste, and I
have consequently determined upon submitting it to a new investi-
gation."

VOL. V. D

34 COSMOS.

tion. In a portion of my work, which treats of volcanic pheno-
mena, I cannot wholly pass in silence those problems, which
have been suggested by other inquirers in reference to the
currents pervading the general fluid in the interior of our
planet, or the probable or improbable periodically ebbing
and flowing movement in individual and imperfectly filled
basins, or the existence of portions of space, having a very
low specific gravity and underlying the upheaved mountain
chains29 In a work devoted to cosmical phenomena
no question should be overlooked on which actual observa-
tions have been instituted, or which may seem to be eluci-
dated by close analogies.

b. The Existence and Distribution of Heat in tlie interior of
our Globe.

(Expansion of the Delineation of Nature,
Cosmos, vol. i, pp. 160 — 168.)

Considerations regarding the internal heat of our earth,
the importance of which has been greatly augmented by the
connection which is now generally recognised to exist be-
tween it and phenomena of upheavals and of volcanic action,
are based partly upon direct, and therefore incontrovertible
measurements of temperature in springs, borings, and sub-
terranean mines, and partly upon analytical combinations
regarding the gradual cooling of our planet, and the influence
which the decrease of heat may have exercised in primeval
ages upon the velocity of rotation and upon the direction
of the currents of internal heat.30 The figure of the com-
pressed terrestrial spheroid is further dependent upon the
law, according to which density increases in concentric
superimposed non-homogeneous strata. The first or experi-
mental, and therefore the more certain portion of the in-
vestigation to which we shall limit ourselves in the present
place, throws light only upon the accessible crust of the
earth, which is of very inconsiderable thickness, whilst the

-9 See Petit sur la latitude de I' Observatoire de Toulouse,^ la density
moyenne de la cliaine des Pyrenees, et la probabilite quil existe un vide
sous cette cliaine, in the Comptes rendus de I'Acad. des Sc., t. xxix, 1849,
p. 730.

80 Cosmos, vol. i, p. 1 69.

THE HEAT OF THE EARTH. 35

second or mathematical part, in accordance with the nature
of its applications, yields rather negative than positive results.
This method of enquiry, which possesses all the charm of
ingenious and intellectual combinations of thought,31 leads
to problems, which cannot be wholly overlooked when we
touch upon conjectures regarding the origin of volcanic
forces, and the reaction of the fused interior upon the solid
external crust of our earth. Plato's geognostic myth of
the Pyriphlegethon,32 as the origin of all thermic springs as
well as of volcanic igneous currents, emanated from the early
and generally felt requirement of discovering some common*
?ause for a great and complicated series of phenomena.

Amid the multiplicity of relations presented by the
earth's surface, in respect to insolation (solar action) and
its capacity of radiating heat, and amid the great differences
in the capacity for conducting heat, which varies in ac-
cordance with the composition and density of hetero-
geneous rocks, it is worthy of notice, that wherever the
observations have been conducted with care, and under
favourable circumstances, the increase of the temperature
with the depth has been found to present for the most part
very closely coinciding results, even at very different lo-
calities. For very great depths we obtain the most certain
results from Artesian wells, especially when they are filled
with fluids that have been rendered turbid by the admixture
of clay, and are therefore less favourable to the passage of
internal currents, and when they do not receive many lateral
affluents flowing into them at different elevations through
transverse fissures. On account of their depth, we will
begin with two of the most remarkable Artesian wells,
namely that of Grenelle, near Paris, and that of the New
Salt Works at Oeynhausen, near Minden. We will proceed
in the following paragraph to give some of the most accurate
results which they have yielded.

According to the ingenious measurements of Walferdin,38

31 Hopkins, Physical Geology, in the Report of the British Association
for 1838, p. 92; Philos. Transact., 1839, pt. ii, p. 381, and 1840, pt. i,
p. 193; Hennessey (Terrestrial Physics) in the Philos. Transact., 1851,
pt. ii, pp. 504—525.

3-3 Cosmos, vol. i, p. 235.

33 The observations of Walferdin were made in the autumn of 1847,
and deviate very slightly from the results obtained with the same appa«

D 2

36 COSMOS.

to whom we are indebted for a complete series of very deli
cate apparatus for determinations of temperature at great
dfpths in the sea and in springs, the surface of the basin
of the well at Grenelle lies at an elevation of 36.24 metres
or 119 feet above the level of the sea. The upper outlet
of the ascending spring is 33.33 metres or 109.3 feet higher.
This total elevation of the ascending water (69.57 metres or
228.2 feet) is, when compared with the level of the sea about
196'8 feet lower than the outbreak of the green sandstone
strata in the hills near Lusigny, south-east of Paris, to
whose infiltrations the rise of the waters in the Artesian
wells at C i:enelle have been ascribed. The borings extend
to a depth of 547 metres or 1794.6 feet below the base of
the Grenelle basin, or about 510.76 metres or 1675 feet
below the level of the sea ; the waters consequently rise to a
total height of 580.33 metres or 1904 feet. The tempe-
rature of the spring is 8l°.95 F. ; consequently the increase
of heat marks 1° F. for about every 59 feet.

The boring at the New Salt Works at Eehme is situated
231 feet above the level of the sea (above the watermark at
Amsterdam). It has penetrated to an absolute depth of 2281
feet below the surface of the earth, measuring from the point
M here the operations were begun. The salt spring which,
when it bursts forth, is impregnated with a large quantity
of carbonic acid, lies therefore 2052 feet below the level of
the sea, a relative depth which is perhaps the greatest that
has ever been reached by man in the interior of the earth.
The temperature of the salt spring at the New Salt Works
of Oeynhausen is 91° 04 F., and as the mean annual tem-
perature of the air at these works is about 49°. 3 F., we
may assume that there is an increase of temperature of
1° F. for every 54.68 feet. The boring at these Salt Works34
is therefore 491 feet absolutelv deeper than the boring at

ratus, by Arago, in 1840, at a depth of 1657 feet, when the borer had
left the chalk and was beginning to penetrate through the gault. See
Cosmos, vol. i, p. 167, and Comptes rendus, t. xi, 1840, p. 707.

34 According to the manuscript results given by the superintendent
of the mines of Oeynhausen. See Cosmos, vol. i, pp. 148, 166 ; and
Bischof, Lehrbuch der Chem. und Phys Geologic, Bd. i, Abth. 1, s. 154
— 163. In regard to absolute depth, the borings at Mondorf, in the
Grand Duchy of Luxemburg (2202 feet), approach most nearly to those
at the new salt works at Oeynhauseu.

INTERNAL HEAT OP THE EARTH. 37

Grenelle ; it sinks 377 feet deeper below the surface of the
sea, and the temperature of its waters is 9°. 18 F. higher.
The increase of the heat at Paris, is about 1° F. for 59
feet, and therefore scarcely T]7th greater. I have already else-
where drawn attention to the fact that a similar result was
obtained by Auguste de la Rive and Marcet, at Bregny, near
Geneva, in investigating a boring which was only 725 feet
in depth, although it was situated at an elevation of more
than 1600 feet above the Mediterranean Sea.35

If to these three springs, which possess an absolute depth
varying between 725 feet and 2285 feet, we add another, that
of Monkwearmouth, near Newcastle, (the water rising
through a coal mine which, according to Phillips is worked
at a depth of 1496 feet below the level of the sea,) we
shall find this remarkable result, that at four places widely
separated from one another an increase of heat of 1° F.
varies only between 54 and 58.6 feet;36 such a coincidence
in the results cannot, however, be always expected to occur
when we consider the nature of the means which are em-
ployed for determining the internal heat of the earth at
definite depths. Although we may assume that the water
which is infiltrated in elevated positions through hydrostatic
pressure as in connected tubes, may influence the rising of
springs at points of great depth, and that the subterranean

35 Cosmos, vol. i, p. 166, and Memoires de la Societe d'ffist. Naturelle de
Geneve, t. vi, 1833, p. 243. The comparison of a number of Artesian
wells in the neighbourhood of Lille, with those of Saint Ouen and
Geneva would, indeed, lead us to assume, if we were quite certain as to
the accuracy of the numerical data, that the different conductive powers
of terrestrial and rocky strata exert a more considerable influence
than has generally been supposed (Poisson, Theorie Matliematlgue de
la Chaleur, p. 421).

36 In a table of foxirteen borings, which were more than one hundred
yards in depth, and which were situated in various parts of France,
Bravais, in his very instructive encyclopaedic memoir in the Patria,
1847, p. 145, indicates nine in which an increase of temperature of
1° F. is found to occur for every 50 — 70 feet of depth, which would
give a deviation of about 10 feet in either direction from the mean
value given in the text. See also Magnus in Poggen. Ann. Bd. xxii, 1831,
B. 146. It would appear, on the whole, that the increase of tempera-
ture is most rapid in Artesian wells of very inconsiderable depth,
although the very deep wells of Monte Massi in Tuscany, and Neuffen
on the north-west part of the Swabian Alps, present a remarkable ex-
ception to this rule.

38 COSMOS.

waters acquire the temperature of the terrestrial strata with
which they are brought in contact, the water that is ob-
tained through borings may, in certain cases, when communi-
cating with vertically descending fissures, obtain some aug-
mentation of heat from an inaccessible depth. An influence
of this kind, which is very different from that of the varying
conductive power of different rocks, may occur at individual
points widely distant from the original boring. It is pro-
bable that the waters in the interior of our earth move in
some cases within limited spaces, flowing either in streams
through fissures (on which account it is not unusual to find
that a few only of a large number of contiguous borings prove
successful), or else follow a horizontal direction, and thus form
extensive basins — a relation which greatly favours the labour
of boring, and in some rare cases betrays, by the presence of
eels, mussels, or vegetable remains, a connection with the
earth's surface. Although from the causes which we have
already indicated, the ascending springs are sometimes
warmer than the slight depth of the boring would lead
us to anticipate, the afflux of colder water which flows
laterally through transverse fissures leads to an opposite
result.

It has already been observed that points situated on the
same vertical line at an inconsiderable depth within the
interior of our earth, experience at very different times
the maximum and minimum of atmospheric temperature,
which is modified by the sun's place, and by the seasons of
the year. According to the very accurate observations of
Quetelet, daily variations of temperature are not percep-
tible at depths of 3fths feet below the surface ;37 and at
"Brussels, the highest temperature was not indicated until
Jie 10th of December in a thermometer which had been
Hunk to a depth of more than 25 feet, whilst the lowest tem-
perature was observed on the 15th of June. In like manner,
in the admirable experiments made by Professor Forbes, in
the neighbourhood of Edinburgh, on the conductive power of
different rocks, the maximum of heat was not observed until
the 8th of January in the basaltic trap of Calton Hill at
a depth of 24 feet below the surface.38 It would appear

# Quetelet, in the Bulletin de I'Acad. de Bruxelles, 1836, p. 75.

38 Forbes, Exper. on the temperature of the earth at different depth*

INVARIABLE TEMPERATURE. 39

from the observations which were carried on for many
years by Arago in the garden of the Paris Observatory, that
very small differences of temperature were perceptible 30
feet below the surface. Bravais calculated one degree for
about every 50 feet on the high northern latitude of Bosse-
kop, in Finmark (69° 58' JS. L.). The difference between
the highest and lowest annual temperature diminishes in
proportion with the depth, and according to Fourrier this
difference diminishes in a geometrical proportion as the
depth increases in an arithmetical ratio.

The stratum of invariable temperature depends, in respect
to its depth, conjointly upon the latitude of the place,
the conductive power of the surrounding strata and the
amount of difference of temperature between the hottest
and the coldest seasons of the year. In the latitude
of Paris (48° 50') the depth and temperature of the Caves
de rObservatoire (86 feet and 53°.30 F.) are usually re-
garded as affording the amount of depth and temperature
of the invariable stratum. Since Cassini and Legentil in
1783 placed a very correct mercurial thermometer in
these subterranean caves, which are portions of old stone
quarries, the mercury in the tube has risen about 0°.4.39
Whether the cause of this rising is to be ascribed to an
accidental alteration in the thermometrical scale which,
however, was adjusted by Arago in 1817 with his usual
care, or whether it indicates an actual increase of heat is
still undecided. The mean temperature of the air at Paris
is 51°. 478 F. Bravais is of opinion that the thermometer
in the Caves de V Observatoire stands below the limit cf
invariable temperature, although Cassini believes that he
has found a difference of TVotfts °f a degree (Fahr.) between
the winter and summer temperature, the higher tempe-

in the Trans, of the Royal Soc. of Edinburgh, vol. xvi, 1849, pt. ii,
p. 189.

39 All numbers refeiTing to the temperature of the Caves de V Obser-
vatoire have been taken from the work of Poisson, Theorie Mathema-
tique de la Chaleur, pp. 415 and 462. The Annuaire Meteoroloyique de la
France, edited by Martins and Haeghens, 1849, p. 88, contains correc-
tions by Gay-Cussac for Lavoisier's subterranean thermometer. The
mean of three readings, from June till August, was 5 3°. 9 5 F. for
this thermometer, at a time when Gay-Lussac found the temperature
to be 53°.32, which was therefore a difference of 0°.63.

40 COSMOS.

rature being found to prevail in the winter.40 If we now
take the mean of many observations of the temperature
of the soil between the parallels of Zurich (47° 22') and
Upsala (59° 51'), we obtain an increase of 1° F. for every
40 feet. Differences of latitude cannot produce a difference
of more than 12 or 15 feet, which is not marked by any
regular alteration from south to north, because the influence
which the latitude undoubtedly exerts, is masked within
these narrow limits by the influence of the conductive
power of the soil, and by errors of observation.

As the terrestrial stratum in which we first cease to ob-
serve any alteration of temperature through the whole year
lies, according to the theory of the distribution of heat, so
much the nearer the surface, as the maxima and minima of
the mean annual temperature approximate to one another, a
consideration of this subject has led my friend Boussingault
to the ingenious and convenient method of determining the
mean temperature of a place within the tropical regions
(especially between 10 degrees north and south of the
equator) by observing a thermometer which has been baried
8 or 12 inches below the surface of the soil in some well
protected spot. At different hours and different months of
the year, as in the experiments of Captain Hall near the
coast of the Choco in Tumaco, those at Salaza in Quito, and
those of Boussingault in la Vega de Zupia, Marmato, and
Anserina Nuevo in the Cauca valley, the temperature
scarcely varied one-tenth of a degree ; and almost within
the same limits it was identical with the mean temperature
of the air at those places in which it had been determined
by horary observations. It was, moreover, very remarkable
that this identity remained perfectly uniform, whether the
thermcmetric soundings (of less than one foot in depth)
were made on the torrid shores of Guayaquil and Payta, on
the Pacific, or in an Indian village on the side of the volcano
of Pm-ace, which I found from my barometrical measure-
ments to be situated at an elevation of 1356 toises, or 8671
feet above the sea. The mean temperatures differed by
fully 25° F. at these different stations.41

40 Cassini, in the Mem. de TAcad. des Sciences, 1786, p. 511.

41 Boussingault, sur la profondeur a laquelle on trouve dans la zone
torrlde la couciie de temperature invariable, iu tb.e Annales de Chimie et

INVARIABLE STRATUM. 41

I believe that special attentioD is due to two observations
which I made on the mountains of Peru and Mexico, in
mines which lie at a greater elevation than the summit of
the Peak of Teneriffe, and are therefore the highest in which
a thermometer has ever been placed. At a height of
between 1 2,000 and 18,000 feet above the level of the sea
I found the subterranean air 25° F. warmer than the
external atmosphere. Thus, for instance, the little Peruvian
town of Micuipampa42 lies, according to my astronomical
and hypsometrical observations, in the latitude 6° 43' S.,
and at an elevation of 1857 toises or 11,990 feet, at the
base of Cerro de Gualgayoc, celebrated for the richness of
its silver mines. The summit of this almost isolated
fortress-like and picturesquely situated mountain rises 240
toises or 1504 feet higher than the streets of Micuipampa ;
the external air at a distance from the mouth of the pit of

de Physique, t. liii, 1833, pp. 225—247. Objections have been advanced
by John Caldecott, the astronomer to the Rajah of Travaucore, and by
Captain Newbold, in India, against the method recommended in this
memoir, although it has been employed in South America in many
very accurate experiments. Caldecott found at Trevandrum (Edin.
Transact, vol. xvi, part in, pp. 379 — 393), that the temperature of the
soil at a depth of three feet and more below the surface, (and therefore
deeper than Boussingault's calculation,) was 85° and 86° F., while the
mean temperature of the air was 80°.02. Newbold's experiments (Philos.
Transact, for the year 1845, pt. i, p. 133), which were made at Bellary,
lat. 15° 5', showed an increase of temperature of 4° F. between sunrise
and 2 p.m. for one foot of depth, but at Cassargode, lat. 12° 29', there
was only an increase of 1°.30 F., under a cloudy sky. Is it quite cer-
tain that the thermometer in this case was sufficiently covered to pro-
tect it from the influence of the sun's rays? Compare also Forbes,
E.cper. on the Temp, of the Earth at different depths, in the Edin. Tran-
sact, vol. xvi, part ii, p. 189. Colonel A. Costa, the admirable historian
of New Granada, has made a prolonged series of observations, which
fully confirm Boussingault's statement, and which were completed,
about a year ago, at Guadua, on the south-western side of the elevated
plateau of Bogota, where the mean annual temperature is 43°.94 F. at
the depth of one foot, and at a carefully protected spot. Boussingault
thus refers to these experiments: — "The observations of Colonel A.
Costa, whose extreme precision in everything which is connected with
meteorology is well known to you, prove that when fully sheltered from
all disturbing influences, the temperature within the tropics remains
constant at a very small depth below the surface."

4- In reference to Gualgayoc (or Minas de Chota) and Micuipampa,
see Humboldt, Recueil d'Observ. Astron. vol. i, p. 324.

42 COSMOS.

the Mina del Purgatorio was 42°.26 F., but in the interior
of the mine, which lies more than 2057 toises, or 13,154 feet
above the sea, I saw that the thermometer everywhere indi-
cated a temperature of 67°.64 F., there being thus a differ-
ence of 25°. 38 F. The limestone rock was here perfectly
dry, and very few men were working in the mine. In the
Mina de Guadalupe, which lies at the same elevation, I
found that the temperature of the internal .air was 57°.9 F.,
showing therefore a difference of 15°. 6 4 F. when compared
with the external air. The water which flowed out from
the very damp mine stood at 52°.34 F. The mean annual
temperature of Micuipampa is probably not more than
45°. 8 F. Iii Mexico, in the rich silver mines of Guanaxuato,*3
I found in the Mina de Valenciana the external temperature
in the neighbourhood of the Tiro Nuevo (which is 7590 feet
above the sea) 70°. 16 F., and the air in the deepest mines, for
instance in the Planes de San Bernardo, 1630 feet below the
opening of the shaft of Tiro Nuevo, fully 80°. 6 F., which is
about the mean temperature of the littoral region of the
Gulf of Mexico. At a point 147 feet higher than the
mouth of the Planes de San Bernardo, a spring of water
issues from the transverse rock, in which the temperature is
84°.74 F. I determined the latitude of the mountain town
of Guanaxuato to be 21° 0' 1ST., with a mean annual tem-
perature varying between 60°.44 and 61°. 26 F. The present
is not a fitting place in which to advance conjectures, which
it might be difficult to establish in relation to the causes of
probably an entirely local rise of the subterranean tempera-
ture at mountain elevations, varying from 6000 to more
than 12,000 feet.

A remarkable contrast is exhibited in the steppes of Nor-
thern Asia, by the conditions of the frozen soil, whose very
existence was doubted, notwithstanding the early testimony
of Gmelin and Pallas. It is only in recent times that cor-
rect views in relation to the distribution and thickness of
the stratum of subterranean ice have been established by
means of the admirable investigations of Erman, Baer, and
Middendorff. In accordance with the descriptions given of
Greenland by Cranz, of Spitzbergen by Martens and Phipps,

43 Essai Polit. sur k Roy. de la Nouv. Espagne (2&me ed., t. iii,
P. 201).

THE FROZEN SOIL. 43

and of the coasts of the sea of Kara by Sujew, the whole of the
most northern part of Siberia was described by too hasty a
generalization as entirely devoid of vegetation, always frozen
on the surface, and covered with perpetual snow, even in the
plains. The extreme limit of vegetation in Northern Asia
is not, as was long assumed, in the parallel of 67°, although
sea -winds and the neighbourhood of the Bay of Obi make
this estimate true for Obdorsk ; for in the valley of the
great River Lena, high trees grow as far north as the lati-
tude of 71°. Even in the desolate islands of New Siberia,
large herds of reindeer and countless lemmings find an
adequate nourishment.** MiddendorfFs two Siberian expe-
ditions, which are distinguished by a spirit of keen observa-
tion, adventurous daring, and the greatest perseverance in a
laborious undertaking, were extended from the year 1843 to
1846 as far north as the Taymir land in 75° 45' lat., and
south-east as far as the Upper Amoor and the Sea of Ocbotsk.
The former of these perilous undertakings led the learned
investigator into a hitherto unvisited region, whose explora-
tion was the more important in consequence of its being
situated at equal distances from the eastern and western
coasts of the old Continent. In addition to the distribution
of organisms in high northern latitudes, as depending mainly
upon climatic relations, it was directed by the St. Peters-
burgh Academy of Sciences that the accurate determination
of the temperature of the ground and of the thickness of the
subterranean frozen soil should be made the principal objects
of the expedition. Observations were made in borings and
mines at a depth of from 20 to 60 feet at more than twelve
points (near Turuchansk, on the Jenisei, and on the Lena) at
relative distances of from 1600 to 2000 geographical miles.

The most important seat of these geothermic observations
was however Schergin's shaft at Jakutsk 62° 2' N. lat.45

44 E. von Baer, in MiddendorfFs Reise in Sib., Bd. i, s. vii.

45 The merchant Fedor Schergin, cashier to the Russian- American
Trading Company, began, in the year 1828, to dig a well in the court-
yard of a house belonging to the company. As he had only found
frozen earth and no water at the depth of 90 feet, which he reached in
1830, he determined to give up the attempt, until Admiral Wrangel,
who passed through Jakutsk on his way to Sitcha, in Russian America,
and who saw how interesting it would be, in a scientific point of view,
to penetrate through this subterranean stratum of ice, induced Schergin

44 COSMOS.

Here a subterranean stratum of ice was pierced to a depth
of more than 382 feet. The thermometer was sunk at
eleven points along the lateral walls of the shaft between
the surface and the greatest depth, which was reached in
1837. The observer was obliged to be let down standing in
a bucket, with one arm fastened to a rope, while he read off
the thermometric scale. The series of observations, whose
mean error does not amount to more than 0°. 45 F. embrace
the interval between April 1844 and June 1846. The
decrease of cold was not proportional to the depth at indi-
vidual points, but nevertheless the following results were
obtained for the total increase of the mean temperatures for
the different superimposed frozen strata : —

50 feet - - 17°.13F.

100 „ - - 20°.26 „

150 „ 21°.43 „

200 „ 23°.27 „

250 „ 24°.49 „

382 „ 26°.60 „

After a very careful consideration of all these observations,
Middendorff determined the general increase of tempera-
ture to be 1° F. for eveiy space varying from 44°.5 to 52
feet.46 This result shows a more rapid increase of heat in

to continue the boring ; and, up to 1837, although an opening had
been made to a depth of 382 feet below the surface, it had not pene-
trated beyond the ice.

46 Middendorff, Reise in Sib. Bd. i, s. 125 — 133. "If we exclude,"
says Middendorff, "those depths which did not quite reach 100 feet,
on the ground that they were influenced by annual deviations of tem-
perature, as was determined by experiments previously made in Siberia,
we shall still find certain anomalies in the partial increase of heat.
Thus, for instance, between the depths of 150 — 200 feet the tempera-
ture rises at a ratio of 1° F. for only 29.3 feet, while between 250 —
300 feet the corresponding increase is 96.4 feet. We may, therefore,
venture to assert that the results of observations that have hitherto
been obtained in Shergin's shaft are by no means sufficient to deter-
mine with certainty the amount of the increase of temperature, and
that, notwithstanding the great variations which may depend upon the
different conductive powers of the terrestrial strata, and the disturbing
influence of the air or water which enters from above, an increase of
1° F. occurs for every 44 — 52 feet. The result of 52 feet is the mean of
BI'X partial increases of temperature, measured at intervals of 50 feet
between the depths of 100 and 882 feet. On comparing the mean

THE TEMPE^iJLt'eARTH. 45

Schergin's shaft than has been obtained from different bor-
ings in Central Europe, whose results approximate closely to
one another (see p. 37). The difference fluctuates between
i-th and -|th. The mean annual temperature of Jakutsk was
determined at 13°.7 F. The oscillation between the summer
and winter temperature is so great, according to Newerow's
observations, which were continued for fifteen years (from
1829 to 1844), that sometimes for fourteen days consecutively
in July and August, the atmospheric temperature rises as
high as 77,° or even 84°.6 F., while during 120 consecutive
winter days from November to February, the cold falls to
between — 42°. 3 F. and — 69° F. In estimating the increase
of temperature which was found on boring through the
frozen soil, we must take into account the depth below the

annual temperature of Jakutsk 13°.71 F. with that which was found
from observation to be the mean temperature of the ice (26°.6) at the
greatest depth of the mine (382 feet), I find 29.6 feet for every increase
of 1° F. A comparison of the temperature at the deepest part with
that at a depth of 100 feet would give 44.4 feet for this increase. From
the acute investigations of Middendorff and Peters in reference to the
velocity of transmission of changes of atmospheric temperature, in-
cluding the maxima of cold and heat (Middend. s. 133—157, 163—175),
it follows that in the different borings which do not exceed the in-
considerable depth of from 8 to 20 feet, " the temperature rises from
March to October, and falls from November to April, because the
spring and autumn are the seasons of the year in which the changes of
atmospheric temperature are most considerable" (s. 142 — 145). Even
carefully covered mines in Northern Siberia become gradually cooled,
in consequence of the walls of the shafts having been for years in con-
tact with the air; this cause, however, has only made the temperature
fall about 1° F. in Schergin's shaft, in the course of eighteen years.
A remarkable and hitherto unexplained phenomenon, which has also
presented itself in the Schergin shaft, is the warmth occasionally ob-
served in the winter, although only at the lowest strata, without any
appreciable influence from without (s. 156 — 178). It seems still more
striking to me, that in the borings at Wedeusk, on the Pasina, when
the atmospheric temperature is — 31° F. it should be 26°. -4 at the
inconsiderable depth of 5 or 10 feet ! The isogeothermal lines, whose
direction was first pointed out by Kupffer, in his admirable in-
vestigations (Cosmos, vol. i, p. 216) will long continue to present prob-
lems that we are unable to solve. The solution of these problems is
more e-pecially difficult in those cases in which the complete perfora-
tion of the frozen soil is a work of considerable time; we can, however,
no longer regard the frozen soil at Jakutsk as a merely local pheno-
menon, which, in accordance with Slobin's view, is produced by the
terrestrial strata deposited from water (Middend. s. 167).

46 COSMOS.

surface at which the ice exhibits the temperature of 32° F.,
and which is consequently the nearest to the lower limit of
the frozen soil ; according to MiddendorfTs results which
entirely agree with those that had been obtained much earlier
by Erman, this point was found in Schergin's shaft to be 652,
or 684 feet below the surface. It would appear, however,
from the increase of temperature which was observed in the
mines of Mangan, Shilow and Dawydow, which are situated
at about three or four miles from Irkutsk, in the chain of
hills on the left bank of the Lena, and which are scarcely
more than 60 feet in depth, that the normal stratum of perpe-
tual frost seems to be situated at 320 feet below the surface.47
Is this inequality only apparent in consequence of the un-
certainty which attaches to a numerical determination, based
on so inconsiderable a depth, and does the increase of tem-
perature obey different laws at different times ? Is it
certain that if we were to make a horizontal section of
several hundred fathoms from the deepest part of Schergin's
shaft into the adjoining country, we should find in every
direction and at every distance from the mine frozen soil, in
which the thermometer would indicate a temperature of 4°. 5
below the freezing point ?

Schrenk has examined the frozen soil in 67° 30' N. L. in
the country of the Samojedes. In the neighbourhood of
Pustojenskoy Gorodok, fire is employed to facilitate the
sinking of wells, and in the middle of summer ice was found
at only 5 feet below the surface. This stratum could be
traced for nearly 70 feet, when the works were suddenly
stopped. The inhabitants were able to sledge over the
neighbouring lake of Usteje throughout the whole of the
summer of 1813.48 During my Siberian expedition with
Ehrenberg and Gustav Rose, we caused a boring to be made

47 Middendorff, Bd. i, s. 160, 164, 179. In these numerical data and
conjectures regarding the thickness of the frozen soil, it is assumed
that the temperature increases in arithmetical progression with the
depth. Whether a retardation of this increase occurs in greater depths
is theoretically uncertain, and hence there is no use in entering upon
deceptive calculations regarding the temperature of the centre of the
earth in the fused heterogeneous rocky masses which give rise to
currents.

48 Schrenk's Reise durck die Tundern der Samoje.den, 1848, Th. i,
B. 597.

THE FROZEN SOIL. 47

in a piece of turfy ground near Bogoslowsk (59° 44' N. L.)
among the Ural Mountains on the road to the Turjin mines.**
We found pieces of ice at the depth of 5 feet, which were
embedded, breccia-like, in the frozen ground, below which
began a stratum of thick ice which we had not penetrated
at the depth of 10 feet.

The geographical extension of the frozen ground, that is to
say, the limits within which ice and frozen earth are found
at a certain depth, even in the month of August, and con-
sequently throughout the whole year, in the most northern
parts of the Scandinavian peninsula, as far east as the coasts
of Asia, depends, according to Middendorff' s acute obser-
vations (like all geothermal relations) more upon local
influences than upon the temperature of the atmosphere.
The influence of the latter is on the whole, no doubt, stronger
than any other, but the isogeothermal lines are not, as
Kupffer has remarked, parallel in their convex and concave
cuives to climatic isothermal lines, which are determined by
the means of the atmospheric temperature. The infiltration
of Hquid vapours deposited by the air, the rising of thermal
springs from a depth, and the varying conductive powers of
the soil, appear to be especially active.80 " On the most nor-
thern point of the European continent, in Finmark, between
the high latitudes of 70° and 71°, there is as yet no con-
tinuous tract of frozen soil. To the eastward, impinging
upon the valley of the Obi, 5° south of the North Cape, we
find frozen ground at Obdorsk and Beresow. To the east
and south-east of this point, the cold of the soil increases,
excepting at Tobolsk on the Irtisch, where the temperature
of the soil is colder than at Witimsk, in the valley of the
Lena, which lies 1° farther north. Turuchansk (65° 54'
JN . L.) on the Jenisei, is situated upon an unfrozen soil,
although it is close to the limits of the ice. The soil at
Ainginsk, south-east of Jakutsk, presents as low a tempera-
ture as that of Obdorsk, which lies 5" farther north ; the same
being the case with Oleminsk on the Jenisei. From the Obi
to the latter river the curve formed by the limits of the

49 Gustav Rose, Reise nach. dem Ural, Bd. i, s. 428.

50 Compare my friend, G. von Helmersen's experiments on the rela-
tive conductive powers of ditferent kinds of rocks (Mem. de I' Academic
de St. Petcrsbourg : Melanges Physiques et Chimifjues, 1851, p. 32).

48 t COSMOS.

frozen soil seems to rise a couple of degrees farther north,
after which it intersects, as it turns southward, the Lena
valley, almost 8° south of the Jenessei. Farther eastward,
this line again rises in a northerly direction."61 Kupffer, who
has visited the mines of I^ertshinsk, draws attention to the
fact that independently of the continuous northern mass of
frozen soil, the phenomenon occurs in an island-like form
in the more southern districts, but in general it is entirely
independent of the limits of vegetation, or of the growth of
timber.

It is a very considerable advance in our knowledge, when
we are able gradually to arrive at general and sound cosmical
viows of the relations of temperature of our earth in the
northern portions of the old continent ; and to recognise the
fact that under different meridians the limits of the frozen
soil as well as those of the mean annual temperature,
and of the growth of trees, are situated at very different
latitudes ; whence it is obvious that continuous currents of
heat must be generated in the interior of our planet.
Franklin found in the north-west part of America that the
ground was frozen even in the middle of August at a depth
of 16 inches, while Richardson observed upon a more eastern
point of the coast in 71° 12' lat. that the ice-stratum was
thawed in July as low as 3 feet beneath the herb-covered
surface. Would that scientific travellers would afford us
more general information regarding the geothermal relations
in this part of the earth and in the southern hemisphere !
An insight into the connection of phenomena is the most
certain means of leading us to the causes of apparently in-
volved anomalies, and to the comprehension of that which
we are apt too hastily to regard as at variance with normal
laws.

31 Middendorff, Bd. i, s. 166. Compare also s. 179. "The curve re-
presenting the commencement of the freezing of the soil in Northern
Asia exhibits two convexities, inclining southwards, one on the Obi,
which is very inconsiderable, and the other on the Lena, which is much
more strongly marked. The limit of the frozen soil passes from Ber-
resow on the Obi, towards Turuchansk on the Jenisei, it then runs
between Witirnsk and Oleminsk, on the right bank of the Leua, and,
ascending northwards, turns to the east."

49

c. Magnetic Activity of the Earth in its tliree Manifestations
of Force — Intensity, Inclination, and Variation. — Points
(called the Magnetic Poles), in which the Inclination is 90°.
— Curves on which no Inclination is observed (Magnetic
Equator). — The Four different Maxima of Intensity. —
Curve of weakest Intensity. — Extraordinary Disturbances of
the Declination (Magnetic Storms). — Polar Light.

(Extension of the Picture of Nature, Cosmos, vol. i. pp. 169
—197, vol. ii. pp. 717—720, and vol. iv. pp. 394—398.)

The magnetic constitution of our planet can only be
deduced from the many and various manifestations of ter-
restrial force in as far as it presents measureable relations in
space acd time. These manifestations have the peculiar pro-
perty of exhibiting perpetual variability of phenomena to a
much higher degree even than the temperature, gaseous
admixture, and electrical tension of the lower strata of the
atmosphere. Such a constant change in the nearly allied
magnetic and electrical conditions of matter moreover essen-
tially distinguishes the phenomena of electro-magnetism
from those which are influenced by the primitive funda-
mental force of matter — its molecular attraction and the
attraction of masses at definite distances. To establish
laws in that which is ever varying, is however the highest
object of every investigation of a physical force. Although
it has been shown by the labours of Coulomb and Arago
that the electro-magnetic process may be excited in the
most various substances, it has nevertheless been proved
by Faraday's brilliant discovery of diamagnetism, (by the
differences of the direction of the axes, whether they incline
north and south, or east and west,) '•hat the heterogeneity of
matter exerts an influence distinct from the attraction of
masses. Oxygen gas, when inclosed in a thin glass tube, will
show itself under the action of a magnet to be paramagnetic,
inclining north and south like iron ; and while nitrogen,
hydrogen, and carbonic acid gases remain unaffected, phos-
phorus, leather, and wood show themselves to be diamag-
netic, and arrange themselves equatorially from east to west,

voi* v. K

50 COSMOS.

The ancient Greeks and Romans were acquainted with the
adhesion of iron to the magnet, attraction and repulsion, and
the transmission of the attracting action through brass ves-
sels as well as through rings, which were strung together in a
chain-like form, as long as one of the rings was kept in con-
tact with the magnet ;M and they were likewise acquainted
with the non-attraction of wood and of all metals excepting
iron. The force of polarity, which the magnet is able to
impart to a moveable body susceptible, of its influence, was
entirely unknown to the Western nations (Phoenicians, Tus-
cans, Greeks, and Romans). The first notice which we meet
with among the nations of Western Europe of the knowledge
of this force of polarity, which has exerted so important an
influence on the improvement and extension of navigation,
and which, from its utilitarian value has led so continuously
to the inquiry after one universally diffused, although pre-
viously unobserved force of nature, does not date farther back
tliMitho llth and 12th centuries. In the history and enu-
meration of the principal epochs of a physical contempla-
tion of the universe, it has been found necessary to divide
into several sections, and to notice, the sources from which
vre derive our knowledge of that which we have here sum-
marily arranged under one common point of view.53

We find that the application amongst the Chinese of the
directive power of the magnet, or the use of the north and
south direction of magnetic needles floating on the surface of
water, dates to an epoch which is probably more ancient
than the Doric migration and the return of the Heraclidse
into the Peloponnesus. It seems, moreover, very striking
that the use of the south direction of the needle should have
been first applied in Eastern Asia not to navigation but to
land travelling. In the anterior part of the magnetic waggon
a freely floating needle moved the arm and band of a small
figure, which pointed towards the south. An apparatus of
this kind (called fse-nan, indicator of the south,) was pre-

52 The principal passage referring to the magnetic chain of rings
occurs in Plato's Ion. p. 533, D.E ed. Steph. Mention has been made
of this transmission of the attracting action not only by Pliny (xxxiv,
14) and Lucretius (vi, 910), but also by Augustine (de civitate Dei,
xx, 4) and Philo (de Mwndi opificio, p. 32 D ed. 1691).

53 Cosmos, vol. i, p. 182 ; vol. ii, p. 628.

THE MAGNETIC NEEDLE. 51

.sented during the dynasty of the Tscheu, 1100 years before
our era, to the ambassadors of Tonquin and Cochin-China,
to guide them over the vast plains, which they would have
to cross in their homeward journey. The magnetic waggon
was used as late as the loth century of our era.64 Several
of these waggons were carefully preserved in the imperial
palace and were employed in the building of Buddhist mon-
asteries in fixing the points towards which the main sides
of the edifice should be directed. The frequent application
of magnetic apparatus gradually led the more intelligent
of the people to physical considerations regarding the nature
of magnetic phenomena. The Chinese eulogist of the mag-
netic needle, .Kuopho (a writer of the age of Constantine the
Great), compares, as I have already elsewhere remarked, th^
attractive force of the magnet with that of rubbed amber.
This force, according to him, is " like a breath of wind
which mysteriously breathes through these two bodies, and
has the property of thoroughly permeating them with the
rapidity of an arrow." The symbolical expression of " breath
of wind " reminds us of the equally symbolical designation of
soul, which in Grecian antiquity was applied by Thales, the
founder of the Ionian School, to both these attracting sub-
stances ; soid signifying here the inner principle of the mov-
ing agent.65

54 Humboldt, Asie Centrale, t. i, p. xl — xlii, and Examen Crit. de
VHist. de la Geographic, t. iii, p. 35. Eduard Biot, who has extended
and confirmed by his own careful and bibliographical studies, and with
the assistance of ray learned friend Stanislas Julien, the investigations
made by Klaproth in reference to the epoch at which the magnetic
needle was first used in China, adduces an old tradition, according to
which the magnetic waggon was already in use in the reign of the Em-
peror Hoang-ti. No allusion to this tradition can, however, be found in
any writers prior to the early Christian ages. This celebrated monarch
is presumed to have lived 2600 years before our era (that is to say,
1000 years before the expulsion of the Hyksos from Egypt). Ed. Biot
fur la direction de I' aiguille aimantee en Chine in. the Comptes rendus de
TAcad. des Sciences, t. xix, 1844, p. 822.

55 Cosmos, vol. i, p. 182. Aristotle (de Anima, i, 2) speaks only of
the animation of the magnet as of an opinion that originated with
Thales. Diogenes Laertius interprets this statement as applying also
distinctly to amber, for he says, " Aristotle and Hippias maintain as to
the doctrine enounced by Thales." . . . The sophist Hippias of Elis,
who flattered himself that he possessed universal knowledge, occupied
himself with physical science and with the most ancient traditions of

E2

82 COSMOS.

As the excessive mobility of the floating Chinese needles
rendered it difficult to observe, and note down the ir*dica-
tions which they afforded, another arrangement was adopted
in their place as early as the 12th century of our era, in
which the needle that was freely suspended in the air was
attached to a fine cotton or silken thread exactly in the
same manner as Couiomb's suspension which was first used
by William Gilbert in Western Europe. By means of this
more perfect apparatus,66 the Chinese as early as the begin-
ning of the 12th century determined the amount of the
western variation, which in that portion of Asia seems only
to undergo very inconsiderable and slow changes. From its
use on land, the compass was finally adapted to maritime
purposes, and under the dynasty of Tsin, in the 4th century
of our era, Chinese vessels under the guidance of the conp.pass
visited Indian ports and the eastern coast of Africa.

Fully 200 years earlier, under the reign of Marcus Aurelius
Antoninus, who is called An-tun by the writers of the
dynasty of Han, Roman legates came by sea by way of Ton-
quin to China. The application of the magnetic needle to
European navigation was however not owing to so transient
a source of intercourse, for it was not until its use had
become general thoughout the whole of the Indian Ocean,
along the shores of Persia and Arabia, that it was introduced
into the West in the 12th century, either directly through
the influence of the Arabs or through the agency of the
Crusaders, who since 1096 had been brought in contact with
Egypt and the true Oriental regions. In. historical investi-
gations of this nature, we can only determine with certainty

the physiological school. " The attracting breath," which, according
to the Chinese physicist, Kuopho, "permeates both the magnet and
amber," reminds us, according to Buschmann's investigations into the
Mexican language, of the aztec name of the magnet tlaihioanani tetl,
signifying " the stone which attracts by its breath" (from ihiotl, breath,
and nna, to draw or attract).

56 The remarks which Klaproth has extracted from the Penthsaoyan
regarding this singular apparatus are given more fully in the Mung-
kld-vi-than, Comptes rendus, t. xix, p. 365. We may here ask why, in
this latter treatise, as well as in a Chinese book on plants, it is stated
that the cypress turns towards the west, and, more generally, that the
magnetic needle points towards the south? Does this imply a more
luxuriant development of the branches on the side nearest the sun, or
in consequence of the direction of the prevalent winds?

THE MARINER'S COMPASS. 53

those epochs, which must be considered as the latest limits
beyond which it would be impossible for us to nrge oiit
inquiries. In the politico-satirical poem of Guyot of Pro-
vins, the mariner's compass is spoken of (1199) as an instru-
ment that had been long known to the Christian world ; and
this is also the case in the description of Palestine which we
owe to the Bishop of Ptolemais, Jaques de Vitry, and which
was completed between the years 1204 and 1215. Guided
by the magnetic needle the Catalans sailed along the north-
ern islands of Scotland as well as along the western shores of
tropical Africa, the Basques ventured forth in search of the
whale, and the Northmen made their way to the Azores
(the Bracir islands of Picigano). The Spanish Leyes de las
Partidas (del sabio Rey Don Alonso el nono), belonging to
the first half of the 13th century, extolled the magnetic
needle as " the true mediatrix (medianera) between the mag-
netic stone (la piedra) and the north star." Gilbert also, in
his celebrated work De Magnete Physiologia Nova, speaks of
the mariner's compass as a Chinese invention, although he
inconsiderately adds, that Marco Polo " qui apud Chinas
artem pyxidis didicit," first brought it to Italy. As, how-
ever, Marco Polo began his travels in 1271 and returned in
1295, it is evident from the testimony of Guyot of Provins
and Jaques de Vitry, that the compass was at all events used
in European seas from 60 to 70 years before Marco Polo set
forth on his journeyings. The designations zohron and
aphron, which Vincent of Beauvais applied in his Mirror of
Nature to the southern and northern ends of the magnetic
needle (1254), seem to indicate that it was through Arabian
pilots that Europeans became possessed of the Chinese com-
pass. These designations point to the same learned and
industrious nation of the Asiatic peninsula whose language
too often vainly appeals to us in our celestial maps and
globes.

From the remarks which I have already made, there can
scarcely be a doubt that the general application of the
magnetic needle by Europeans to oceanic navigation as early
as the 12th century, and perhaps even earlier in individual
cases, originally proceeded from the basin of the Mediter-
ranean. The most essential share in its use seems to have
belonged to the Moorish pilots, the Genoese, Venetians,

64 COSMOS.

Majorcans, and Catalans. The latter people, under the
guidance of their celebrated countryman, the navigator, Don
Jaime Ferrer, penetrated, in 1346, to the mouth of the Rio
de Ouro (23° 40' KL.), on the Western Coast of Africa, and,
according to the testimony of Raymundus Lullus (in his
nautical work Fenix de las Maravillas del Orbe, 1286) the
Barcelonians employed atlases, astrolabes, and compasses,
long before Jaime Ferrer.

The knowledge of the amount of magnetic variation is of
a very early date, and was simultaneously imparted by the
Chinese to Indian, Malay, and Arabian seamen, through whose
agency it must necessarily have spread along the shores of
the Mediterranean. This element of navigation, which is so
indispensable to the correction of a ship's reckoning, was then
determined less by the rising and setting of the sun than by
the polar star, and in both cases the determination was very
uncertain ; notwithstanding which, we find it marked down
upon charts, as for instance upon the very scarce atlas of
Andrea Bianco, which was drawn out in the year 1436.
Columbus, who had no more claim than Sebastian Cabot,
to be regarded as the first discoverer of the variation of
the magnetic needle, had the great merit of determining
astronomically the position of a line of no variation 2^°
east of the Island of Corvo, in the Azores, on the 13th
of September, 1492. He found, as he penetrated into the
western part of the Atlantic Ocean, that the variation
passed gradually from north-east to north-west. This obser-
vation led him to the idea, which has so much occupied navi-
gators in later times, of finding the longitude by the position
of the curves of variation which he still imagined to be
parallel to the meridian. We learn from his ship's log, that
when he was uncertain of his position during his second
voyage (1496), he actually endeavoured to steer his way by
observing the declination. The insight into the possibility
of such a method was undoubtedly that uncommunicable
secret of longitude, which Sebastian Cabot boasted on his
deathbed of having acquired through special divine mani-
festation.

The idea of a curve of no declination in the Atlantic was
associated in the easily excited fancy of Columbus with
other somewhat vague views of alterations of climate, of an

VARIATION-CHAETS. 55

anomalous configuration of the earth, and of extraordinary
motions of the heavenly bodies, in which he found a motive
for converting a physical into a political boundary line.
Thus the raya, on which the agujas de marear point directly
to the polar star, became the line of demarcation between the
kingdoms of Portugal and Castille ; and from the importance
of determining with astronomical exactness the geographical
length of such a boundary in both hemispheres, and over
every part of the earth's surface, an arrogant Papal decree,
although it failed in effecting this aim, nevertheless exerted a
beneficial effect on the extension of astroiiomico-nautical
science and on the improvement of magnetic instruments.
(Humboldt, Examen Grit, de la Geog., t. iii, p. 54.) Felipe
Guillen, of Seville, in 1525, and probably still earlier, the
cosmographer Alonso de Santa Cvuz, teacher of mathematics
to the young Emperor Charles V., constructed new variation
compasses by which solar altitudes could be taken. The latter
in 1530, and therefore fully 150 years before Halley, drew
up the first general variation chart, although it was certainly
based upon very imperfect materials. We may form some
idea of the interest that had been excited in reference to ter-
restrial magnetism in the 1 6th century, after the death of
Columbus, and during the contest regarding the line of
demarcation, when we find that Juan Jay me made a voyage
in 1585, with Francisco Gali, from the Philippines to Aca-
pulco, for the sole purpose of testing by a long trial in the
South Sea a Declinatorium of his own invention.

Amid this generally diffused taste for practical observation,
we trace the same tendency to theoretical speculations which
always accompanies or even more frequently precedes the
former. Many old traditions current amongst Indian and
Arabian sailors, speak of rocky islands which bring death and
destruction to the hapless mariner, by attracting through
their magnetic force all the iron which connects together the
planks of the ship, or even by immoveably fixing the entire
vessel. The effect of such delusions as these was to give rise
to a conception of the concurrence, at the poles, o± lines 01
magnetic variation, represented materially under the image
of a high magnetic rock lying near one of the poles. On the
remarkable chart of the New Continent, which was added to
the Latin edition of 1508 of the Geography of Ptolemy, we

56 COSMOS.

find that north of Greenland (Gruenllant), which is repre-
sented as belonging to the eastern portion of Asia, the north
magnetic pole is depicted as an insular mountain. Its
position was gradually marked as being farther south in the
£reve Compendia de la Sphera, by Martin Cortez, 1545, as
well as in the Geographia di Tolomeo of Liveo Sanuto, 1588.
The attainment of this point, called el calamitico, was asso-
ciated with great expectations, since it was supposed in
accordance with a delusion, which was not dissipated till
long afterwards, that some miraculoso stupendo effetto would
be experienced by those who reached it.

Until towards the end of the 16th century, men occupied
themselves only with those phenomena of variation which
exerted a direct influence on the ship's reckoning and the
determination of its place at sea. Instead of the one line of
no variation, which had been found by Columbus in 1492,
the learned Jesuit Acosta, who had been instructed by Por-
tuguese pilots (1589) expressed the belief in his admirable
Historia Natural de las Indias that he was able to indicate
four such lines. As the ship's reckoning, together with the
accurate determination of the direction (or of the angle
measured by the corrected compass) also requires the distance
the ship had made, the introduction of the log, although this
mode of measuring is even at the present day very imperfect,
nevertheless marked an important epoch in the history of
navigation. I believe that I have proved, although contrary
to previously adopted opinions, that the first certain evidence
of the use of the log 67 (la cadena de la popa, la corredera)
occurs in the journal which was kept by Antonio Pigafetta
during the voyage of Magellan, and which refers to the
month of January, 1521. Columbus, Juan de la Cosa, Se-

57 Cosmos, vol. ii, pp. 631 — 634. In the time of King Edward III. of
England, when, as Sir Harris Nicolas (History of the Royal Navy,
1847, vol. ii, p. 180), has shown, ships were guided by the compass,
which was then called the sailstone dial, sailing needle, or adamant, we
find it expressly stated in the accounts of the expemes for equipping the
king's ship, "The George," in the year 1345, that sixteen hour-glasses
had been bought in Flanders ; this statement, however, is by no means
a proof of the use of the log. The ampolletas (or hour-glasses) of the
Spaniards were, as we most plainly find from the statements of Enciso
in Cespides, in use long before the introduction of the log, "echamlo
\juuto por fantasia in la corredera de los perezosos."

MAGNETISATION. 57

bastian Cabot, and Vasco de Gama, were not acquainted
with the log and its mode of application, and they estimated
the ship's speed merely by the eye, while they found the
distance they had made by the running down of the sand in
the glasses known as ampolletas. For a considerable period
the horizontal declination from the north pole was the only
element of magnetic force that was made use of, but, at
length (in 1576), the second element, inclination, began to be
first measured. Robert Norman was the first who deter-
mined the inclination of the magnetic needle in London,
which he noted with no slight degree of accuracy by means
of an inclinatorium, which he had himself invented. It was
not until 200 years afterwards, that attempts were made to
measure the third element, the intensity of the magnetic
terrestrial force.

About the close of the 16th century, William Gilbert, a
man who excited the admiration of Galileo, although his
merits were wholly unappreciated by Bacon, first laid down
comprehensive views of the magnetic force of the earth.58
He clearly distinguished magnetism from electricity by their
several effects, although he looked upon both as emanations
of one and the same fundamental force, pervading all matter.
Like other men of genius, he had obtained many happy
results from feeble analogies, and the clear views which he
had taken of terrestrial magnetism (de magno magnete
tellure) led him to ascribe the magnetisation of the vertical
iron rods on the steeples of old church towers to the effect
of this force. He, too, was the first in Europe who showed
that iron might be rendered magnetic by being touched with
the magnet, although the Chinese had been aware of the fact
nearly 500 years before him.59 Even then, Gilbert gave

58 Cosmos, vol. i, p. 170. Calamitico was the name given to these
instruments in consequence of the first needles for the compass
having been made in the shape of a frog.

59 See Gilbert, Physiologia Nova de Magnete, lib. iii, cap. viii, p. 124.
Even Pliny (Cosmos, vol. i, p. 170), remarks generally, without, how-
ever, referring to the act of touching, that magnetism may be im-
parted for a long period of time to iron. Gilbert expresses himself as
follows in reference to the vulgar opinion of a magnetic mountain : —
" vulgiris opinio de montibus magneticis aut rupe aliqua magnetica, de
polo phantastico a polo mundi distante" (1. c. p. 42 — 98). The variation
and advance of the magnetic lines were entirely unknown to him.
•' Varietas uniuscujusque bci constana est" (1. c. 42, 98, 152, 153.

58 COSMOS.

steel the preference over soft iron, because the former has the
power of more permanently retaining the force imparted to
it, and of thus becoming for a longer time a conductor of
magnetism.

In the course of the 17th century, the navigation of the
Netherlander^ British, Spaniards and French, which had
been so widely extended by more perfect methods of deter-
mining the direction and length of the ship's course, increased
the knowledge of those lines of no variation which, as I have
already remarked, Father Acosta had endeavoured to reduce
into a system.60 Cornelius van Schouten indicated, in 1616,
points lying in the midst of the Pacific and south-east of
the Marquesas Islands in which the variation was null.
Even now there lies in this region a singular, closed system
of isogonic lines, in which every group of the internal con-
centric curves indicates a smaller amount of variation.61
The emulation which was exhibited in trying to find methods
for determining longitudes, not only by means of the varia-
tion, but also by the inclination (which when it was observed
under a cloudy starless sky, aere caliginoso?2 was said by
Wright to be "worth much gold") led to the multiplication
of instruments for magnetic observations, while it tended at
the same time to increase the activity of the observers. The
Jesuit Cabeus of Ferrara, Ridley, Lieutaud (1668), and
Henry Bond (1676), distinguished themselves in this manner.
Indeed, the contest between the latter and Beckborrow,
together with Acosta's view that there were four lines of no
variation which divided the entire surface of the earth, may
very probably have had some influence on the theory, ad-
vanced in 1683 by Halley, of four magnetic poles or points
of convergence.

66 Historia Natural de las Indias, lib. i, cap. 17.

61 Cosmos, vol. i, p. 175.

62 In the very careful observations of inclination which I made on the
Pacific, I demonstrated the conditions under which an acquaintance
with the amount of the inclination may be of important practical
utility in the determination of the latitude during the prevalence, on
the coasts of Peru, of the Garua, when both the sun and stars are ob-
scured (Cosmos, vol. i, p. 173). The Jesuit, Cabeus, author of the Phi'
losophia Maynetica (in qua nova qusedam pyxis explicatur, quse poli

7 elevationem, ubique demonstrat), drew attention to this fact during the
first half of the 17th century.

THE MAGNETIC POLES. 59

Halley is identified with an important epoch in the history
of terrestrial magnetism. He assumed that there was in
each hemisphere a magnetic pole of greater and lesssr
intensity, consequently four points with 90° inclination of
the needle, precisely as we now find among liie four points of
greatest intensity an analogous inequality in the maximum
of intensity for each hemisphere, that is to say, in the
rapidity of the oscillations of the needle in the direction of
the magnetic meridian. The pole of greatest intensity was
situated, according to Halley, in 70° S.L. 120° east of
Greenwich, and therefore almost in the meridian of King
George's Sound in New Holland (Nuyts Land).63 Halley's
three voyages, which were made in the years 1698, 1699,
and 1702, were undertaken with the view of elaborating a
theory which must have owed its origin solely to the earlier
voyage which he had made seven years before to St. Helena,
and to the imperfect observations of variation made by
Baffin, Hudson, and Cornelius van Schouten. These were
the first expeditions which were equipped by any government
for the establishment of a great scientific object — that of
observing one of the elements of terrestrial force on which
the safety of navigation is especially dependent. As Halley
penetrated to 52° south of the equator, he was able to
construct the first circumstantial variation chart, which
affords to the theoretical labours of the 19th century a point
of comparison, although certainly not a very remote one, of
the advancing movement of the curves of variation.

Halley's attempt to combine graphically together by lines
different points of equal variation was a very happy one,64
since it has given us a comprehensive and clear insight into
the connection of the results already accumulated. My iso-
thermal lines (that is to say lines of equal heat or mean
annual summer and winter temperature), which were early

63 Edmund Halley, in the Philos. Transact, for 1683, vol. xii, No. 148.
p. 216.

64 Lines of this kind, which he called tractus chalyboeliticos, were
marked down upon a chart by Father Christopher Burrus, in Lisbon,
and offered by him to the King of Spain for a large sum of money ;
these lines being drawn for the purpose of showing and determining
longitudes at sea. See Kircher:s Magnes, ed. 2, p. 443. The first varia-
tion chart, which was made in 1530, has already been referred to IL. tko
text (p. 56).

60 COSMOS.

received with much favour by physicists, have been formed
on a similar plan to Halley's isogonic curves. These lines,
especially since they have been extended and greatly im-
proved by Dove, are intended to afford a clear view of the
distribution of heat on the earth's surface, and of the princi-
pal dependence of this distribution on the form of the solid
and fluid parts of the earth, and the reciprocal position of
continental and oceanic masses. Halley's purely scientific
expeditions stand so much the more apart from others, since
they were not, like many later expeditions, fitted out at the
expense of the Government with the object of making geo-
graphical discoveries. In addition to the results which they
have yielded in respect to terrestrial magnetism, they were
also the means of affording us an important catalogue of
southern stars as the fruits of Halley's earlier sojourn in the
Island of St. Helena in the years 1677 and 1678. This
catalogue was moreover the first that was drawn up after
telescopes had been combined, according to Morin's and
Gascoigne's methods, with instruments of measurement.65

As the 17th century had been distinguished by an
advance in a more thorough knowledge of the position
of the lines of variation, and by the first theoretical
attempt to determine their points of convergence, viz. the
magnetic poles, the 18th century was characterised by
the discovery of horary periodical alterations of variation.
Graham has the incontestable merit of being the first to
observe (London, 1722) these hourly variations with accuracy
and persistency. Celsius and Hiorter in Upsala,66 who main-
tained a correspondence with him, contributed to the exten-
sion of our knowledge of this phenomenon. Brugmans, and
after him Coulomb, who was endowed with higher mathe-
matical powers, entered profoundly into the nature of ter-

65 Twenty years after Halley had drawn up his catalogue of southern
stars at St. Helena (which, unfortunately, included none under the
sixth magnitude) Hevelius boasted, in his Firmamentum Sobescianum,
that he did not employ any telescope, but observed the heavens through
fissures. Halley, who, during his visit to Dantzic in 1679, was present
at these observations, praises their exactness somewhat too highly.
Cosmos, vol. iii, p. 52.

66 Traces of the diurnal and horary variations of the magnetic force
had been observed in London as early as 1634, by Hellibrand, and in
Slam, by Father Tachard, in 1682.

MAGNETIC INTENSITY. 61

restrial magnetism (1784 — 1788). Their ingenious physical
experiments embraced the magnetic attraction of all matter,
the local distribution of the force in a magnetic rod of a
given form, and the law of its action ar a distance. In order
to obtain accurate results, the vibrations of a horizontal
needle suspended by a thread, as well as deflections by a
torsion balance, were in turn employed.

The knowledge of the difference of intensity of ter-
restrial magnetism at different points of the earth's surface
by the measurement of the vibrations of a vertical needle
ID. the magnetic meridian, is due solely to the ingenuity
of the Chevalier Borda ; ~Dt from any series of speciallv
successful experiments, but by a process of reasoning, and
by the decided influence which he exerted on those who
were equipping themselves for remote expeditions. Borda's
long cherished conjectures were first confirmed by means
of observations made from the year 1785 to 1787, by
i^amanon, the companion of La Perouse. These results
remained unknown, unheeded, and unpublished, although
they had been communicated as early as the summer
of the last-named year to Condorcet, the Secretary of the
Academic des Sciences. The first, and therefore cer-
tainly an imperfect knowledge of the important law of the
variability of intensity in accordance with the magnetic
latitude, belongs undoubtedly67 to the unfortunate but scien-
tifically equipped expedition of La Perouse ; but the law
itself, as 1 rejoice to think, was first incorporated in science
by the publication of my observations, made from 1798 to
1804, in the south of France, in Spain, the Canary Islands,
the interior of tropical America both north and south of the
equator, and in the Atlantic and Pacific Oceans. The suc-
cessful expeditions of Le Gentil, Feuille"e, and Lacaille ; the
first attempt made by Wilke, in 1768, to construct an incli-
nation chart } the memorable circumnavigations of Bougain-
ville, Cook, and Vancouver, have all tended, although by the

G" Cosmos, vol. i, pp. 179 — 181. The admirable construction of the
inclination compass made by Lenoir, according to Borda's plan, the pos-
sibility of having long and free oscillations of the needle, the much
diminished friction of the pivots and the correct adjustment of instru-
ments provided with scales, have been the means of enabling us accu-
rately to measure the amount of the terrestrial force in different zones,

62 COSMOS.

help of instruments possessing very unequal degrees of exact-
ness, to establish the previously neglected, but very important
element of inclination at various intervals of time, and at
many different points ; the observations being made more at
sea and in the immediate vicinity of the ocean than in the
interior of continents. Towards the close of the 18th
century, the stationary observations of declination which
were made by Cassini, Gilpin, and Beaufoy (from 1784 to
1790), with more perfect instruments, showed definitely that
there is a periodical influence at different hours of the day,
no less than at different seasons of the year, — a discovery
which imparted a new stimulus to magnetic investigations.

In the 19th century, half of which has now expired, this
increased activity has assumed a special character differing
from any that has preceded it. We refer to the almost
simultaneous advance that has been made in all branches of
the theory of terrestrial magnetism, comprising the numerical
determination of the intensity, inclination and variation of
the force ; in physical discoveries in respect to the excitation
and the amount of the distribution of magnetism ; and in
the first and brilliant suggestions of a theory of terrestrial
magnetism, which has been based by its founder, Friedrich
Gauss, upon strictly mathematical combinations. The means
which have led to these results are improvements in the
instruments and methods employed ; scientific maritime
expeditions, which in number and magnitude have exceeded
those of any other century, and which have been carefully
equipped at the expense of their respective Governments,
and favoured by the happy choice both of the commanders
and of the observers who have accompanied them ; and
various expeditions by land, which having penetrated far
into the interior of continents, have been able to elucidate
the phenomena of terrestrial magnetism, and to establish a
large number of fixed stations, situated in both hemispheres
in corresponding north and south latitudes, and often in
almost opposite longitudes. These observatories, which are
both magnetic and meteorological, form as it were a net-
work over the earth's surface. By means of the ingenious
combination of the observations which have been published
at the national expense in Russia and England, important
and unexpected results have been obtained. Tlie establish-

PROGRESS IN MAGNETISM. 63

men! of a law regulating the manifestation of force which is
a proximate, although not the ultimate, end of all investiga-
tions, has been satisfactorily effected in many individual
phases of the phenomenon. All that has been discovered by
means of physical experiments concerning the relations
which terrestrial magnetism bears to excited electricity, to
radiating heat and to light, and ail that we may assume in
reference to the only lately generalised phenomena of dia-
magnetism, and to that specific property of atmospheric
oxygen — polarity — opens at all events the cheering prospect,
that we are drawing nearer to the actual nature of the
magnetic force.

In order to justify the praise which we have generally ex-
pressed in reference to the magnetic labours of the first half
of our century, I will here, in accordance with the nature
and form of the present work, briefly enumerate the principal
sources of our information, arranging them in some cases
chronologically, and in others in groups. w

1803 — 1806. Krusenstern's voyage round the world (1812);
the magnetic and astronomical portion was by Horner (Bd. iii,
s. 317).

1804. Investigation of the law of the increase in the in-
tensity of terrestrial magnetic force from the magnetic
equator northward and southward, based upon observations
made from 1799 to 1804. (Humboldt, Voyage aux Regions
Equinoxiales du Nouveau Continent, t. iii, pp. 615 — 623 ;
Lametherie, Journal de Pliysique, t. Ixix, 1804, p. 433 ; the
first sketch of a chart showing the intensities of the force,
Cosmos, vol. i, p. 179). Later observations have shown that
the minimum of the intensity does not correspond to the
magnetic equator, and that the increase of the intensity
in both hemispheres does not extend to the magnetic pole.

1805 — 1806. Gay-Lussac and Humboldt, Observations of
Intensity in the south of France, Italy, Switzerland, and
Germany. Memoir "es de la Societe d'Arcueil, t. i. pp. 1 — 22.

pp.

839,

Compare the observations of Quetelet, 1830 and 1839, with a

68 The dates with which the following table begins (as, for instance,
from 1803 — 1806) indicate the epoch of the observation, while the
figures which are marked in brackets, and appended to the titles of the
works, indicate the date of their publication, which was frequently
much later.

t COSMOS.

" Carte de Tintensite magnetique horizontale entre Paris et
Naples," in the Mem. de VAcad. de Bruxelles, t. xiv ; the
observations of Forbes in Germany, Flanders, and Italy in
1832 and 1837 (Transact, of the Royal Soc. of Edinburgh,
vol. xv, p. 27) ; the extremely accurate observations of Biid-
berg in France, Germany, and Sweden, 1832 ; the observa-
tions of Dr. Bache (Director of the Coasts' Survey of the
United States), 1837 and 1840, at 21 stations both in refer-
ence to inclination and intensity.

1806 — 1807. A long series of observations at Berlin ro
the horary variations of declination and the recurrence c
magnetic storms (perturbations) by Humboldt and Oltmannj
mainly at the periods of the solstices and equinoxes for [
and 6, or even sometimes 9 days, and as many nights conse
cutively, by means of Prony's magnetic telescope which
allowed arcs of 7 or 8 seconds to be distinguished.

1812. Morichini, of Borne, maintained that non-magnetic
steel-needles become magnetic by contact with the violet
rays of light. Regarding the long contention excited by this
assertion and the ingenious experiments of Mrs. Somer-
ville, together with the wholly negative results of Biess and
Moser, see Sir David Brewster, Treatise on Magnetism, 1837,
p. 48.

-1 o-i f> i Q1 Q ~\

18<>3— 1896' i ^e *wo circumnavioati°n voyages of Otto
von Kotzebue, the first in the Buric, the second, five years
later, in the Predprijatie.

1817 — 1848. The series of great scientific maritime expe-
ditions equipped by the French Government, and which
yielded such rich results to our knowledge of terrestrial
magnetism ; beginning with Freycinet's voyage in the cor-
vette Uranie 1817 — 1820, and followed by Duperrey in the
frigate La Coquille 1822 — 1825, Bougainville in the frigate
Thetis 1824—1826, Dumont d'Urville in the Astrolabe
1826 — 1829, and to the south pole in the Zelee 1837—1840,
Jules De Blosseville to India 1828 (Herbert Asiat. Re-
searches, vol. xviii, p. 4, Humboldt, Asie Cent. t. iii, p. 468),
and to Iceland 1833, (Lottin, Voy. de la Recherche 1836,
pp. 376 — 409), du Petit Thouars with Tessan in the Venus
1837—1839, le Vaillant in the Bonite 1836—1837, the
voyage of the " Commission scientifique du Nord " (Lottin,

ARCTIC EXPEDITIONS. G£

Bravais, Martins, Siljestrom) to Scandinavia, Lapland, the
Faroe Islands, and Spitzbergen in the corvette la Recherche
1835—1840, Berard to the Gulf of Mexico and North
America 1838, to the Cape of Good Hope and St. Helena
1842 and 1846 (Sabine in the Phil Transact, for 1849,
pt. ii, p. 175), and Francis de Castlenau, Voy. dans les parties
centralvs de V Amerique du Sud 1847 — 1850.

1818 — 1851. The series of important and adventurous ex-
peditions in the ArcticPolar Seas through the instrumentality
of the British Government first suggested by the praise-
worthy zeal of John Barrow ; Edward Sabine's magnetic and
astronomical observations in Sir John Ross's voyage to Davis
Straits, Baffin's Bay, and Lancaster Sound in 1818, as well as
in Parry's voyage in the Hecla and Griper through Barrow
Straits to Melville Island 1819—1820 ; Franklin, Richard-
son, and Back 1819—1822, and ^gain from 1825—1827,
Back alone from 1833 — 1835, when almost the only food
that the expedition could obtain for weeks together was a
lichen, G-yrophora pustulata, the " Tripe de Roche " of the
Canadian hunters, which has been chemically analyzed by
John Stenhouse in the Phil Transact, for 1849, pt. ii, p. 393';
Parry's second expedition with Lyon in the Fury and Hecla
1821 — 1823 ; Parry's third voyage with James Ross 1824 —
1825 ; Parry's fourth voyage when he attempted with Lieu-
tenants Foster and Crozier to penetrate northward from
Spitsbergen on the ice in 1827, when they reached the lati-
tude 82 J 45' ; John Ross, together with his accomplished
nephew Jame.-5 Ross, in a second voyage undertaken at the
expense of Felix Booth, and which was rendered the more
perilous on account of protracted detention in the ice, namely
from 1829 to 1833 ; Dease and Simpson of the Hudson's
Bay Company 1838 — 1839 ; and more recently, in search of
Sir John Franklin, the expeditions of ( 'aptains Ommanney,
Austin, Penny, Sir John Ross, and Phillips 1850 and 1851.
The expedition of Captain Penny reached the northern lati-
tude of 77° & Victoria Channel into which Wellington
Channel opens.

1819 — 1821. Bellinghausen's voyage into the Antarctic
Ocean.

1819. The appearance of the great work of Hansteen On
the Magnetism of the Earth, which, however, was completed

VOL. V. F

66 COSMOS.

as early as 1813. This work has exercised an undoubted
influence on the encouragement and better direction of geo-
magnetic studies, and it was followed by the author's general
charts of the curves of equal inclination and intensity for a
considerable part of the earth's surface.

1819. The observations of Admirals Roussin and G-ivry
on the Brazilian coasts between the mouths of the rivers
Maranon and La Plata.

1819—1820. Oersted made the great discovery of the fact
that a conductor that is being traversed by a closed elec-
tric current, exerts a definite action upon the direction of
the magnetic needle according to their relative positions,
and as long as the current continues uninterrupted. The
earliest extension of this discovery (together with that of
the exhibition of metals from the alkalies and that of the
two kinds of polarization of light — probably the most bril-
liant discovery of the centuiy — )69 was due to Arago's observ-
ation, that a wire, through which an electrical current is
passing, even when made of copper or platinum, attracts
and holds fast iron filings like a magnet, and that needles
introduced into the interior of a galvanic helix become
alternately charged by the opposite magnetic poles in ac-
cordance with the reversed direction of the coils (Ann. de
Chim. et de Phys., t. xv, p. 93). The discovery of these
phenomena, which were exhibited under the most varied
modifications, was followed by Ampere's ingenious theore-
tical combinations regarding the alternating electro-magnetic
actions of the molecules of ponderable bodies. These com-
binations were confirmed by a series of new and highly
ingenious instruments, and led to a knowledge of the laws
of many hitherto apparently contradictory phenomena of
magnetism.

1820 — 1824. Ferdinand von Wrangel's and Anjou's ex-
pedition to the north coasts of Siberia and to the Frozen
Ocean. (Important phenomena of polar light, see th. ii,
s. 259.)

1820. Scoresby's Account of the Arctic Regions ; experi-
ments of magnetic intensity, vol. ii, p. 537 — 554.

1821. Seebeck's discovery of thermo-magnetism and

69 Malus's (1808) and Arago's (1811) ordinary and chromatic polari-
Kution of Light. See Cosmos, vol. ii, p. 715.

MAGNETIC OBSERVATIONS. 67

thermo-electricity. The contact of two unequally warmed
metals (especially bismuth and copper) or differences of tem-
perature in the individual parts of a homogeneous metallic
ring, were recognised as sources of the production of mag-
neto-electric currents.

1821 — 1823. Weddell's voyage into the Antarctic Ocean
as far as lat. 74° 15'.

1822 — 1823. Sabine's two important expeditions for the
accurate determination of the magnetic intensity and the
length of the pendulum in different latitudes (from the east
coasts of Africa to the equator, Brazil, Havannah, Green-
land as far as lat. 74° 32', Norway and Spitzbergen in lat,
79° 50'). The results of these very comprehensive operations
were first published in 1824 under the title of Account of
Experiments to determine the Figure of the Earth, pp. 460
—509.

1824. Erikson's Magnetic Observations along the shores
of the Baltic.

1825. Arago discovers Magnetism of Rotation. The first
suggestion that led to this unexpected discovery was
afforded by his observation on the side of the hill in Green-
wich Park of the decrease in the duration of the oscillations
of an inclination needle by the action of neighbouring non-
magnetic substances. In Arago's rotation experiments, the
oscillations of the needle were affected by water, ice, glass,
charcoal, and mercury.70

1825 — 1827. Magnetic Observations by Boussingault in
different parts of South America (Marmato, Quito).

1826—1827. Observations of Intensity by Keilhau at 20
stations (in Finmark, Spitzbergen, and Bear Island), by
Keilhau and Boeck in Southern Germany and Italy (Schum.
Astr. Nachr. No. 146).

1826 — 1829. Admiral Lutke's voyage round the world;
the magnetic part was most carefully prepared in 1834 by
Lenz (see Partie N antique du Voyage, 1836).

1826 — 1830. Captain Philip Parker King's Observations
in the southern portions of the eastern and western coasts
of South America (Brazil, Monte Video, the Straits of
Magellan, Chili, and Valparaiso).

1827—1839. Quetelet, Etat du Magnetisme Terrestre

7° Cosmos, voL i, p. 172.

F 2

68 COSMOS.

(Bruxell.es) pendant douze annees. Very accurate observa-
tions.

1827. Sabine, On the determination of the relative inten-
sity of the magnetic terrestrial force in Paris and London.
An analogous comparison between Paris and Christiana was
made by Hansteen in 1825—1828 (Meeting of the British
Association at Liverpool 1837, pp. 19 — 23). The many
results of intensity, which had been obtained by French,
English, and Scandinavian travellers, now first admitted of
being brought into numerical connection with oscillating
needles, which had been compared together at the three
above-named cities. These numbers which could therefore
now be established as relative values were' found to be for
Paris 1.348, as determined by myself, for London 1.372
by Sabine, and for Christiana 1.423 by Hansteen. They
all refer to the intensity of the magnetic force at one
point of the magnetic equator (the curve of no inclination)
which intersects the Peruvian Cordilleras between Micui-
pampa and Caxamarca, in south latitude 7° 2' and western
longitude 78° 48', where the intensity was assumed by
myself as = 1.000. This assumed standard (Humboldt,
Mecueil d'Observ. Astr. vol. ii, p. 382 — 385, and Voyage aux
Regions Equin., t. iii, p. 622) formed the basis, for forty
years, of the reductions given in all tables of intensity (Gay-
Lussac in the Mem. de la Societe d'Arcueil, t. i. 1807, p. 21;
Hansteen, On the Magnetism of the Earth, 1819, p. 71 ;
Sabine, in the Hep. of the British Association at Liverpool,
pp. 43 — 58). It has, however, in recent times been justly
objected to on account of its want of general applicability,
because the line of no inclination71 does not connect together

71 " Before the practice was adopted of determining absolute values,
the most generally used scale (find which still continues to be very fre-
quently referred to), was founded on the time of vibration, observed by
Mr. de Humboldt, about the commencement of the present century, at a
station in the Andes of South America, where the direction of the dipping
needle was horizontal, a condition which was for some time erroneously
supposed to be an indication of the minimum of magnetic force at the
earth's surface. From a comparison of the times of vibration of Mr. de
Humboldt' s needle in South America and in Paris, the ratio of the
magnetic force at Paris to what was supposed to be its minimum was
inferred (1.348), and from the results so obtained, combined with a
similar comparison made by myself between Paris and London, in 1827,
with several magnets, the ratio of the force iu London to that of Mr.

MAGNETIC OBSERVATIONS. 69

the points of feeblest intensity (Sabine, in the PJiil. Transact,
for 1846, pt. iii, p. 254, and in the Manual of Sclent. Inquiry
for the use of the British Navy, 1849, p. 17).

1828 — 1829. The voyage of Hansteen and Due : Magne-
tic observations in European Russia and in Eastern Siberia
as far as Irkutsk.

1828 — 1830. Adolf Erman's voyage of circumnavigation,
with his journey through Northern Asia, and his passage
across both oceans, in the Russian frigate Krotkoi. The
identity of the instruments employed, the uniformity of the
methods and the exactness of the astronomical determina-
tions of position will impart a permanent scientific repiita-
tion to this expedition, which was equipped at the expense
of a private individual, and conducted by a thoroughly well-
informed and skilful observer. See the general declination
Chart, based upon Erman's observations in the Report of the
Committee relat. to the Arctic Expedition, 1840, pi. 3.

1828 — 1829. Humboldt's continuation of the observations
begun in 1800 and 1807, at the time of the solstices and
equinoxes regarding horary declination and the epochs of
extraordinary perturbations, carried on in a magnetic pavi-
lion specially erected for the purpose at Berlin, and provided
with one of Gambey's compasses. Corresponding measure-
ments were made at St. Petersburgh, Nikolajew, and in the
mines of Freiberg, by Professor Reich, 227 feet below the
surface of the soil. Dove and Riess continued these observa-
tions in reference to the variation and intensity of the
horizontal magnetic force till November 1830 (Poggend.
Annalen. Bd. xv, s. 318— 336; Bd. xix, s. 375—391, with
16 tab. ; Bd. xx, s. 545—555).

1829—1834. The botanist David Douglas, who met his
death in Owhyhee, by falling into a trap in which a wild
bull had previously been caught, made an admirable series of

de Humboldt's original station in South America has been inferred to
be 1.372 to 1.000. This is the origin of the number 1.372, which has
been generally employed by British observers. By absolute measure-
ments we are not only enabled to compare numerically with one
another the results of experiments made in the most distant parts of
the globe, with apparatus not previously compared, but we also furnish
the means of comparing hereafter the intensity which exists at the pre-
sent epoch, with that which may be found at f uture periods." S&bine,
in the Manual for the use of the British Navy, 1849, p. 17.

70 COSMOS.

observations on declination and intensity along the north-
west coast of America, and upon the Sandwich Islands as
far as the margin of the crater of Kiraueah (Sabine, Rep. of
the Meeting of the British Association at Liverpool, pp. 27
—32).

1829. Kupffer, Voyage au Mont JSlbrouz dans le Caucase,
pp. 68—115.

1829. Humboldt's magnetic observations on terrestrial
magnetism with the simultaneous astronomical determina-
tions of position in an expedition in Northern Asia under-
taken by command of the Emperor Nicholas, between the
longitudes 11° 3' and 80° 12' east of Paris, near the Lake
Dzaisan as well as between the latitudes of 45° 43' (the
island of Birutschicassa in the Caspian Sea) to 58° 52' in
the northern parts of the Ural district near Werchoturie
(Asie. Centrale, t. iii, pp. 440 — 478).

1829. The Imperial Academy of Sciences at St. Peters-
burgh, acceded to Humboldt's suggestion for the establish-
ment of magnetic and meteorological stations in the different
climatic zones of European and Asiatic Russia, as well as for
die erection of a physical central observatory in the capital
of the empire under the efficient scientific direction of Pro-
fessor Kupffer. (See Cosmos, vol. i, p. 184. Kupffer Rap-
port adresse a VAcad. de St. Petersbourg relatif a VObser-
vatoire physique central, fonde aiipres du Corps des Mines,
in Schuni. Astr. Nadir. No. 726 ; and in his Annales Maq-
netiques, p. xi ) Through the continued patronage, which the
Finance Minister, Count Cancrin, has awarded to every
great scientific undertaking, a portion of the simultaneously
corresponding observations72 between the White Sea and

~': The first idea of the utility of a systematic and simultaneously con-
ducted series of magnetic observations is due to Celsius, and, without
referring to the discovery and measurement of the influence of polar
light on magnetic variation, which was, in fact, due to his assistant,
Olav Hiorter (March, 1741), we may mention that he was the means of
inducing Graham, in the summer of 1741, to join him in his inves-
tigations for discovering whether certain extraordinary perturbations,
which had from time to time exerted a horary influence on the
course of the magnetic needle at Upsala had also been observed at the
same time by him in London. A simultaneity in the perturbations
afforded a proof, he said, that the cause of these disturbances is ex-
tended over considerable portions of the earth's surface, and is not
dependent upon accidental local actions (Celsius, in Svenska Veten-

MAGNETIC OBSERVATIONS. 71

the Crimea, and between the Gulf of Finland and the shores
of the Pacific in Russian America, were begun as early as
1832. A permanent magnetic station was established in the
old monastery at Pekin, which, from time to time since the
reign of Peter the Great, has been inhabited by monks of'
the Greek Church. The learned astronomer, Fuss, who took
the principal part in the measurements for the determination
of the difference of level between the Caspian and the Black
Sea was chosen to arrange the first magnetic establishments
in China. At a subsequent period Kupffer in his voyage of
circumnavigation compared together all the instruments
that had been employed in the magnetic and meteorological
stations as far east as Nertschinsk in 119° 36' longitude, and
with the fundamental standards. The magnetic observations
of Fedorow, in Siberia, which are no doubt highly valuable,
are still unpublished.

1830 — 1845. Colonel Graham of the topographical en-
gineers of the United States, made observations on the mag-
netic intensity at the southern boundary of Canada (Phil.
Transact, for 1846, pt. iii, p. 242).

1830. Fuss, Magnetic, Astronomical, and Hypsometrical
Observations on the journey from the Lake of Baikal,
through Ergi-Oude, Durma, and the Gobi, which lies at an
elevation of only 2525 feet, to Pekin, in. order to establish
the magnetic and meteorological observatory in that city,
where Kovanko continued for 10 years to prosecute his
observations (Rep. of the Seventh Meeting of the Brit.
Assoc. 1837, pp. 497—499 ; and Humboldt, Asie Centrale,
t. i, p. 8 ; t. ii, p. 141 ; t. iii, pp. 468, 477).

1831 — 1836. Captain Fitzroy in his voyage round the
world in the Beagle, as well as in the survey of the coasts
of the most southern portions of America, with a Gam-

skaps Academiens Uandlingar for 1740, p. 44 ; Hiorter, op. cit. 1747,
p. 27). As Aragc had recognised that the magnetic perturbations
owing to polar light are diffused over districts, in which the pheno-
mena of light which accompany magnetic storms have not been seen,
he devised a plan, by which he was enabled to carry on simultaneous
horary observations (in 1823) with our common friend Kupffer, at
Kasan, which lies almost 47° east of Paris. Similar simultaneous ob-
servations of declination were begun in 1828 by myself, in conjunction
with Arago and Reich, at Berlin, Paris, and Freiberg (see Poggeud
Annalen, Bd. xix, s. 337).

72 COSMOS.

Ley's inclinatorium and oscillation needles supplied by Han-
steen.

1831. Dunlop, Director of the Observatory of Paramatta,
Observations on a voyage to Australia (Phil. Transact, for
1840, pt. i, pp. 133—140).

1831. Faraday's induction-currents, whose theory has
been extended by Nobili and Antinori. The great discovery
of the development of light by magnets.

1833 and 1839 are the two important epochs of the first
enunciation of the theoretical views of Gauss : (1) Intensitas
vis magneticse terrestris ad mensuram absolutam revocata,
1833 ; (p. 3 : " elementum tertium, intensitas, usque ad
tempora recentiora penitus neglectum mansit ") ; (2) the
immortal work on " the general theory of terrestrial mag-
netism " (see Results of the observations of the Magnetic
Association in the year 1838, edited by Gauss and Weber,
1839, pp. 1—57).

1833. Observations of Barlow on the attraction of the
ship's iron, and the means of determining its deflecting
action on the compass. Investigation of electro- magnetic
currents in Terrellas. Isogonic atlases. Compare Barlow's
Essay on Magnetic Attraction, 1833, p. 89, with Poisson,
sur les deviations de la boussole produite par lefer des vais-
seaux in the Mem de Plnstitut, t. xvi, pp. 481 — 555 ; Airy,
in the Phil. Transact, for 1839, pt. i, p. 167 ; and for 1843,
pt. ii, p. 146 ; Sir James Boss, in the Phil. Transact, for
1849, pt. ii,pp. 177—195).

1833. Moser's methods of ascertaining the position and
force of the variable magnetic pole (Poggend., Annalen, Bd.
xxviii, s. 49—296).

1833. Christie on the Arctic observations of Captain Back.
Phil. Transact, for 1836, pt. ii. p. 377 (Compare also his
earlier and important treatise in the Phil. Transact, for
1825, pt. i. p. 23.)

1834. Parrot's expedition to Ararat (Magnetismus, bd. ii,
s. 53—64).

1836. Major Estcourt, in the expedition of Colonel Ches-
ney on the Euphrates. A portion of the observations on
intensity were lost with the steamer Tigris, which is the
more to be regretted since we are entirely deficient in
accurate observations of this portion of the interior of

MAGNETIC OBSERVATIONS. 73

Western Asia, and of the regions lying south of the Caspian
Sea.

1836. Letter from M. A. de Humboldt to H.R.H. Duke
of Sussex, President of the Royal Society of London, on the
proper means of improving our knowledge of terrestrial mag-
netism by the establishment of magnetic stations and cor-
responding observations (April 1836). On the happy results
of this appeal, and its influence on the great Antarctic expedi-
tion of Sir James Ross, see Cosmos, vol. i, p. 136, and Sir
James Ross's Voyage to the Southern and Antarctic Regions
1817, vol. i, pt, xii.

1837. Sabine, On the Variations of the Magnetic Intensity of
the Earth in the Report of the Seventh Meeting of the British
Association at Liverpool, pp. 1 — 85. The most complete
work of the kind.

1837 — 1838. Erection of a magnetic observatory at Dub-
lin, by Professor Humphrey Lloyd. On the observations
made there from 1840 to 1846 (see Transact, of the Royal
Irish Academy, vol. xxii. pt. i, pp. 74 — 96).

1837. Sir David Brewster, A Treatise on Magnetism,
pp. 185-263.

1837 — 1842. Sir Edward Belcher's voyage to Singapore,
the Chinese Seas, and the western coasts of America (Phil.
Transact, for 1843, pt. ii, pp. 113, 140—142). These observa-
tions of inclination, when compared with my own, which
were made at an earlier date, show a very unequal advance
of the curves. Thus, for instance, in 1803, I found the in-
clinations at Acapulco, Guayaquil, and Callao de Lima to be
+ 38° 48', + 10°42/and— 9° 54'; while Sir Edward Belcher
found + 37° 57', + 9° 1', and — 9° 54'. Can the frequent
earthquakes upon the Peruvian coasts exert a local influence
upon the phenomena, which depend upon magnetic force
of the earth ?

1838—1842. Charles Wilkes's Narrative of the United
States' Exploring Expedition, vol. i, p. xxi.

1838. Lieutenant James Sullivan's Voyage from Falmouth
to the Falkland Islands (Phil. Transact, for 1840, pt. i, pp.
129, 140—143).

1838 and 1839. The establishment of magnetic stations
under the admirable superintendence of General Sabine in
both hemispheres at the expense of the British Government.

74 COSMOS.

The instruments were dispatched in 1839, and the observa-
tions were begun at Toronto and in Van Diemen's Land in
1840, and at the Cape in 1841 (See Sir John Herschel in the
Quarterly Review, vol. Ixvi, 1840, p. 297, and Becquerel,
Traite d* Electricite et de Magnetisme, t. vi, p. 173). By the
careful and thorough elaboration of these valuable observa-
tions, which embrace all the elements or variations of the
magnetic activity of the earth, General Sabiiie as superin-
tendent of the Colonial observatories, discovered hitherto
unrecognized laws, and disclosed new views in relation to the
science of magnetism. The results of his investigations were
collected by himself in a long series of separate memoirs (Con-
tributions to terrestrial magnetism) in the Philosophical
Transactions of the Royal Society of London, and in separate
works, which constitute the basis of this portion of the
Cosmos. We will here indicate only a few of the most im-
portant (1) Observations on days of unusual magnetic disturb-
ances (storms) in the years 1840 o*kf 1841, pp. 1 — 107, and as
a continuation of this treatise, magnetic storms from 1843 —
1845 in the Phil. Transact, for 1851, pt. i, pp. 123-139,
(2) Observations made at the Magnetical Observatory at Toronto
1840,1841, andl842(43039'KLat, and 81°41'W. Long.)vol.i,
pp. xiv — xxviii; (3) The very variable direction of magnetic de-
clination in one-half of the year at Long wood House, St. Selena
(15° 55' S. Lat., 8° 3' W. Long.), Philosophical Transactions
for 1847, pt. i, p. 54; (4) Observ. made at the Magn. and Meteor.
Observatory at the Cape of Good Hope 1841—1846; (5) Observ.
made at the Magn. and Meteor. Observatory at Hobarton
(42° 52' S. Lat., 145° 7' E. Long.) in Van Diemen's Land and
the Antarctic expedition, vol. i and ii, (1841 — 1848) ; on the se-
paration of the eastern and western disturbances, see vol. ii, pp.
ix — xxxvi; (6) Magnetic phenomena within the Antarctic polar
circle inKergueleris and Van Diemen's Land (Phil. Transact.
for 1843, pt.'ii, pp. 145 — 231) ;(7) On the isoclinal and isody-
namic lines in the Atlantic Ocean, their condition in 1837
(Phil. Transact, for 1840, pt. i, pp. 129—155); (8) Basis of a
chart of the Atlantic Ocean which exhibits the lines of
magnetic variation between 60° N. Lat. and 60° S. Lat. for
the year 1840 (Phil. Transact, for 1849, pt. ii,pp. 173—233) ;
(9) Methods of determining the absolute values, secular change,
ind annual variation of the magnetic force (Phil. Transact, f&t

MAGNETIC OBSERVATIONS. 75

1850, pt i, pp. 201 — 219) ; Coincidence of the epochs of the
greatest vicinity of the sun with the greatest intensity of
the force in both hemispheres, and of the increase of inclina-
tion, p. 216 ; (10) On the amount of magnetic intensity in
the most northern parts of the New Continent and upon the
point of greatest magnetic force found by Captain Lefroy in
52° 19' Lat. (Phil. Transactor 1846, pt, iii, pp. 237—336) ;
(11) The periodic alterations of the three elements of terrestrial
magnetism, variation, inclination, and intensity at Toronto
and -Ffobarton, and on the connection of the decennial period
of magnetic alterations with the decennial period of the
frequency of solar spots, discovered by ScJiwabe at Dessau
(Phil. Transact, for 1852, pt. i, pp. 121—124). The observa-
tions of variation for 1846 and 1851 are to be considered as
a continuation of those indicated in Ko. 1. as belonging to
the years 1840—1845.

1839. Representation of magnetic isoclinal and isodynamic
lines from observations of Humphrey Lloyd, John Phillips,
Robert Were Fox, James Ross, and Edward Sabine. As
early as 1833 it was determined at the meeting of the
British Association in Cambridge, that the magnetic inclina-
tion and intensity should be determined at several parts of
the empire, and in the summer of 1834 this suggestion was
fully carried out by Professor Lloyd and General Sabine, and
the operations of 1835 and 1836 were then extended to
Wales and Scotland (Report of the Meeting of the Brit.
Assoc. held at Newcastle, 1838, pp. 49 — 196), with an
isoclinal and isodynamic chart of the British islands, the
intensity at London being taken as = 1.

1838 — 1843. The great exploring voyage of Sir James
Ross to the South Pole, which is alike remarkable for the
additions which it afforded to our knowledge by proving the
existence of hitherto doubtful polar regions, as well as for
the new light which it has diffused over the magnetic con-
dition of large portions of the earth's surface. It embraces
all the three elements of terrestrial magnetism numerically
determined for almost two-thirds of the area of all the
high latitudes of the southern hemisphere.

1839 — 1851. Kreil's observations, which were continued
for 12 years, at the Imperial Observatory at Prague, in
reference to the variation of all the elements of tur-

76 COSMOS.

restrial magnetism, and of the conjectured soli-lunar in-
fluence.

1840. Horary magnetic observations with one of Gambey's
declination compasses during a ten years' residence in Chili,
by Claudio Gay (see his Historia fisica y politica de Chile,
1847).

1840 — 1851. Lamont, Director of the Observatory at
Munich. The results of his magnetic observations, compared
with those of Gottingen, which date back as far as 1835.
Investigation of the important law of a decennial period in
the alterations of declination (see Lamont in Poggend. Ann.
der Phys., 1851, Bd. 84, s. 572—582, and Relshuber, 1852,
Bd. 85, s. 179 — 184). The already indicated conjectural con-
nection between the periodical increase and decrease in the
annual mean for the daily variation of declination in the
magnetic needle, and the periodical frequency of the solar
spots was first made known by General Sabine in the Phil.
Transact, for 1852, and four or five months later, without
any knowledge of the previous observations, the same result
was enunciated by Rudolf Wolf, the learned Director of the
Observatory at Berne.73 Lament's manual of terrestrial mag-
netism, 1848, contains a notice of the newest methods of
observation as well as of the development of these methods.

1840—1845. Bache, Director of the Coasts' Survey of the
United States, Observ. made at the Magn. and Meteorol. Ob-
servatory at Girard's College, Philadelphia (published in
1847).

1840—1842. Lieutenant Gilliss U. S. Magnetical and Me-
teorological Observations made at Washington, published 1847,
pp. 2—319 ; Magnetic Storms, p. 336.

1841 — 1843. Sir Robert Schomburgk's observations of

73 The treatise of Eudolf Wolf, referred to in the text, contains
special daily observation of the sun's spots (from January 1st to June
30th, 1852) and a table of Lament's periodical variations of declination
with Schwabe's results on the frequency of solar spots (3835 — 1850).
These results were laid before the meeting of the Physical Society of
Berne, on the 31st of July, 1852, whilst the more comprehensive
treatise of Sabine (Phil. Transact. 1852, pp. 116 — 121) had been pre-
sented to the Royal Society of London in the beginning of March,
and read in the beginning of May, 1852. From the most recent
investigations of the observations of solar spots, Wolf finds that be-
tween the years 1600 and 1852 the mean period was 11.11 years.

MAGNETIC OBSERA'ATIONS. 77

declination in the woody district of Guiana, between the
mountain Roraima and the village Pirara between the paral-
lels of 4° 57', and 3° 39' (Phil. Transact, for 1849, pt. ii,
p. 217).

1841 — 1845. Magn. and Meteor ol. Observations made at
Madras.

1843 — 1844. Magnetic observations in Sir Thomas Bris-
bane's observatory at Makerstoun, Roxburghshire, 55° 84*
North lat. (see Transact, of the Royal Society of Edin-
vol. xvii, pt. ii, p. 188, and vol. xviii, p. 46).

1843 — 1849. Kreil, On the influence of the Alps upon the
manifestations of the Magnetic Force (see Schum. Astr.
Nachr. No. 602).

1844—1845. Expedition of the Pagoda into high ant-
arctic latitudes as far as 64° and 67°, and from 4° to 117° E.
lon^., embracing all the three elements of terrestrial mag-
netism, under the command of Lieutenant Moore, who had
already served in the Terror in the polar expedition, and of
Lieutenant Clerk, of the Royal Artillery, and formerly
Director of the Magnetic Observatory at the Cape. — A
worthy completion of the labours of Sir James Ross at tho
South Pole.

1845. Proceedings of the Magn. and Meteorol. Conference
held at Cambridge.

1845. Observations made at the Magn. and Meteorol. Ob-
servatory at Bombay under the superintendence of Arthur
Bedford Orlebar. This observatory was erected in 1841,
on the little island of Colaba.

1845 — 1850. Six volumes of the results of the Magn. and
Meteorol. Observations made at the Royal Observatory at
Greenwich. The magnetic house was erected in 1838.

1845. Simonoff. Professor at Kazan, Recherches sur V action
magnetique de la Terre.

1846 — 1849. Captain Elliot, Madras Engineers, Magnetic
Survey of the Eastern Archipelago. Sixteen stations, at each
of which observations were continued for several months in
Borneo, Celebes, Sumatra, the Nicobars, and Keeling Islands,
compared with Madras, between 16° N. lat. and 12° S. lat.
and 78° and 123° E. long. (Phil. Transact, for 1851, pt. i,
pp. 287 — 331, and also pp. i — clvii.) Charts of equal incli-
nation and declination, which also expressed the horizontal

1*8 COSMOS.

and total force, were appended to these observations, which
also give the position of the magnetic equator and of the line
of no variation, and belong to the most distinguished and
comprehensive that had been drawn up in modern times.

1845 — 1850. Faraday's brilliant physical discoveries : (1)
In relation to the axial, or equatorial (diamagnetic74) direction
assumed by freely oscillating bodies under external magnetic
influences (Phil. Transact., for 1846, § 2420, and Phil.
Transact, for 1851, pfc. i, §§ 2718—2796) ; (2) Begarding the
relation of electro-magnetism to a ray of polarized light,
and the rotation of the latter by means of the altered mo-
lecular condition of the bodies through which the ray of
polarized light and the magnetic current have both been
transmitted (Phil. Transact, for 1846, pt. i, § 2195 and
§§2215 — 2221; (3) Regarding the remarkable property
which oxygen (the only gas which is paramagnetic) exerts
on the elements of terrestrial magnetism, namely that like
soft iron, although in a much weaker degree, it assumes con-
ditions of polarity through the diffused action of the body of
the earth, which represents a permanently present magnet7*
(Phil. Transact, for 1851, pt. i, §§ 2297—2967).

74 See Cosmos, vol. iv, p. 396. Diamagnetic repulsion and an
equatorial, that is to say, an east and west position in respect to a
powerful magnet, are exhibited by bismuth, antimony, silver, phos-
phorus, rock salt, ivory, wood, apple-shavings, and leather. Oxygen gas,
either pure or when mixed with other gases, or when condensed in the
interstices of charcoal, is paramagnetic. See in reference to crystallised
bodies the ingenious observations made by Plucker concerning the
position of certain axes (Poggend. Annal. Bd. Ixxiii, s. 178, and Phil.
Transact, for 1851, §§ 2836 — 2842). The repulsion by bismuth was
first recognised by Brngmans, in 1778, next by Le Bailiff, in 1827, and
finally, more thoroughly tested by Seebeck, in 1828. Faraday himself
(§§ 2429—2431), Reich, and Wilhelm Weber, who, from the year 1836,
has shown himself so incessantly active in his endeavours to promote
the progress of terrestrial magnetism, have all endeavoured to exhibit
the connection of diamagnetic phenomena with those of induction
(Poggend. Annalen, Bd. Ixxiii, s. 241 — 253). Weber has, moreover,
tried to prove that diamagnetism derives its source from Ampere's
molecular currents. (Wilh. Weber, A bhandlungen uber electro- dynaniischv
Maassbestimmungen, 1852, s. 545 — 570.)

'5 In order to excite this polarity, the magnetic fluids in every par-
ticle of oxygen must be separated, to a certain extent, by the actio in
distans of the earth in a definite direction, and with a definite force.
Every particle of oxygen thus represents a small magnet, and all these
small magnets react upon one another as well as upon the earth, and

MAGNETIC OBSERVATIONS. 79

1849. Emory, Magn. observations made at the Isthmus of
Panama.

1849. Professor William Thomson, of Glasgow, A Mathe-
matical Theory of Magnetism in the Phil. Transact for 1851,
pt. i. pp. 243 — 285 (On the problem of the distribution of
magnetic force, compare §§42 and 56 with Poisson in the
Mem de V Institut., 1811, pt. i, p. 1 ; pt. ii, p. 163).

1850. Airy, On the present state and prospects of the
science of Terrestrial Magnetism — the fragment of what pro-
mises to be a most admirable treatise.

1852. Kreil, Influence of the Moon on Magnetic Declination
at Prague in the years 1839 — 1849. On the earlier labours
of this accurate observer, between 1836 and 1838, see Osser-
vazioni sulV intensita e sulla direzione della forza magnetica
institute negli anni 1836 — 1838 alV I. E. Osservatorio di
Milano, p. 171 ; and also his Maqnetical and Meteorological
Observations at Prague, vol. i, p. 59.

1852. Faraday, On Lines of Magnetic Force, and their
definite character.

1852. Sabine's new proof deduced from observations at
Toronto, Hobarton, St. Helena, and the Cape of Good Hope
(from 1841 to 1851), that everywhere between the hours of
seven and eight in the morning the magnetic declination
exhibits an annual period ; in which the northern solstice
presents the greatest eastern elongation, and the southern

finally, in connection with the latter, they further act upon a magnetic
needle, which may be assumed to be in or beyond the atmosphere.
The envelope of oxygen that encircles our terrestrial sphere may be com-
pared to an armature of soft iron upon a natural magnet or a piece of
magnetised steel; the magnet may further be assumed to be spherical,
like the earth, while the armature is assumed to be a hollow shell,
similar to the investment of atmospheric oxygen. The magnetic power
which each particle of oxygen may acquire by the constant force of
the earth, diminishes with the temperature and the rarefaction of the
oxygen gas. When a constant alteration of temperature and an expan-
sion follows the sun around the earth from east to west, it must pro-
portionally alter the results of the magnetic force of the earth, and of
the oxygen investment, and this, according to Faraday's opinion, is the
origin of one part of the variations in the elements of terrestrial mag-
netism. Plucker finds that as the force with which the m signet acts
upon the oxygen is proportional to the density of this gas, the magnet
presents a simple eudiometric means of recognising the presence of
free oxygen gas iu a gaseous mixture even to the 100th or 200th
part.

80 COSMOS.

solstice the greatest western elongation, without the tempe-
rature of the atmosphere or of the earth's crust evincing a
maximum or minimum at these turning periods. Compare
the second volume of the Observations made at Toronto, p.
xvii, with the two treatises of Sabine, already referred to on
the Influence of the sun's vicinity (Phil. Transact, for 1850,
pt. i, p. 216), and of the solar spots (Phil. Transact, for 1852,
p. i, p. 121).

The chronological enumeration of the progress of our
knowledge of terrestrial magnetism during half a century,
which I have uninterruptedly watched with the keenest
interest, exhibits a successful striving towards the attainment
of a twofold object. The greater number of these labours
have been devoted to the observation of the magnetic activity
of our planet in its numerical relations to time and space,
while the smaller part belongs to experiments, and to the
manifestation of phenomena, which promise to lead us to the
knowledge of the character of this activity, and of the
internal nature of the magnetic force. Both these methods
— the numerical observation of the manifestation of terres-
trial magnetism, both in respect to its direction and intensity,
— and physical experiments on the magnetic force generally,
have tended reciprocally to the advancement of our physical
knowledge. Observations alone, independently of every
hypothesis regarding the causal connection of phenomena,
or regarding the hitherto immeasurable and unattainable
reciprocal action of molecules in the interior of substances,
have led to important numerical laws. Experimental phy-
sicists have succeeded by the display of the most wondrous
ingenuity in discovering in solid and gaseous bodies polar-
ising properties, whose presence had never before been sus-
pected, and which stand in special relation to the tempera-
ture and pressure of the atmosphere. However important
and undoubted these discoveries may be, they cannot in the
present condition of our knowledge be regarded as satisfactory
grounds of explanation for the laws which have already been
recognized in the movements of the magnetic needle. The
most certain means of enabling us thoroughly to comprehend

HORARY VARIATION. 81

the variable numerical relations of space, as well as to extend
and complete that mathematical theory of terrestrial mag-
netism, which was so nobly sketched by Gauss, is to pro-
secute simultaneous and continuous observations of all the
three elements of the magnetic force at numerous well se-
lected points of the earth's surface. I have, however, else-
where illustrated by example the sanguine hopes which I
entertained of the great advantages that may be derived from
the combination of experimental and mathematical investi-
gation.7*

Nothing that occurs upon our planet can be supposed to
be independent of cosmical influences. The word planet
instinctively -leads us to the idea of dependence upon a
central body, and of a connection with a group of celestial,
bodies of very different masses which probably have a. similar
origin. The influence of the sun's position upon the mani-
festation of the magnetic force of the earth, was recognised
at a very early period. The most distinct intimation of this
relation was afforded by the discovery of horary variation,
although it had been obscurely perceived by Kepler, who, a
century before, had conjectured that all the axes of the planets
were magnetically directed towards one portion of the uni-
Terse. He says expressly, " that the sun may be a magnetic
body, and that on that account, the force which impels the
planets may be centred in the sun."77 The attraction of masses
and gravitation appeared at that time under the semblance
of magnetic attraction. Horrebow.78 who did not confound
gravitation with magnetism, was the first who called the
process of light a perpetual northern light, produced in the
solar atmosphere by means of magnetic forces. Nearer our

76 See p. 6.

77 Kepler, in Stella Martis, pp. 32 — 34 (and compare with it his
treatise, Mysterium Cosmogr. cap. xx, p. 71).

78 Cosmos, vol. iv, p. 386, where, however, in consequence of an
error of the press, in the place of Basis Astronomies we should read
Clavis Astronomic^. The passage (§ 226) in which the luminous process
of the sun is characterised as a perpetual northern light does not occur
in the first edition of the Clavis Astr. by Horrebow (Havn. 1730), but
is only found in the second and enlarged new edition of the work in
Horrebow's Operum Malhematico-Physicorum, t. i, Havn. 1740, p. 317,
as it belongs to this appended portion of the Clavis. Compare with
Horrebow's view the precisely similar views of Sir William and Sir
John Herschel (Cosmos, voL iii, pp. 39, 40).

VOL. V. Q

82 COSMOS.

own times (and this difference of opinion is very remarkable)
two distinct views were promulgated in reference to the
nature of the influence exerted by the sun.

Some physicists, as Canton, Ampere, Christie, Lloyd, and
Airey, have assumed that the sun, without being itself
magnetic, acts upon terrestrial magnetism merely by pro-
ducing changes of temperature, whilst others, as Coulomb,
believed the sun to be enveloped by a magnetic atmosphere7*
which exerts an action on terrestrial magnetism by distribu-
tion. Although Faraday's splendid discovery of the para-
magnetic property of oxygen gas has removed the great diffi-
culty of having to assume with Canton that the temperature
of the solid crust of the earth and of the sea must be rapidly
and considerably elevated from the immediate effect of the
sun's transit through the meridian of the place, the perfect
co-ordination and an ingenious analysis of all the measure-
ments and observations of General Sabine have yielded this
result : that the hitherto observed periodic variations of the
magnetic activity of the earth cannot be based upon periodic
changes of temperature in those parts of the atmosphere
which are accessible to us. Neither the principal epochs of
diurnal and annual alterations of declination at the different-
hours of the day and night, nor the periods of the mean
intensity of the terrestrial force80 coincide with the periods of

79 Memoires de Mathem. et de Phys. presentes a VAcad. Roy. des Sc.
t. ix, 1780, p. 262.

30 "So far as these four stations (Toronto, Hobarton, St. Helena,
and the Cape), so widely separated from each other and so diversely
situated, justify a generalisation, we may arrive at the conclusion that
at the hour of 7 to 8 A.M. the magnetic declination is everywhere sub-
ject to a variation of which the period is a year, and which is every-
where similar in character and amount, consisting of a movement of
the north end of the magnet from east to west, between the northern
and the southern solstice, and a return from west to east between the
southern and the northern solstice, the amplitude being about 5 minute-s
of arc. The turning periods of the year are not, as many might be disposed
to anticipate, those months in which the temperature at the surface of our
planet, or of the subsoil, or of the atmosphere (as far as we possess the
jneans of judging of the temperature of the atmosphere) attains its
maximum and minimum. Stations so diversely situated would, indeed,
present in these respects thermic conditions of great variety ; whereas
uniformity in the epoch of the turning periods is a not less conspicuous
feature in the annual variation than similarity of character and nume-
rical value. At all the stations the solstices are the turning periods of

MAGNETIC INTENSITY. 83

the maxima and minima of the temperature of the atmo-
sphere, or of the upper crust of the earth. We may remark
that the annual alterations were first accurately represented
by Sabine from a very large number of observations. The
turning points in the most important magnetic phenomena
are the solstices and the equinoxes. The epoch at which
the intensity of the terrestrial force is the greatest, and that
at which the dipping needle most nearly assumes the vertical
position in both hemispheres, is identical with the period at
which the earth is nearest to the sun,81 and consequently
when its velocity of translation is the greatest. At this
period, however, when the earth is nearest to the sun, namely
in December, January, and February ; as well as in May,
June,, and July, when it is farthest from the sun, the relations
of temperature of the zones on either side of the equator are
completely reversed, the turning points of the decreasing and

the annual variation at the hour of which we are treating. The only
periods of the year in which the diurnal or horary variation at that
hour does actually disappear are at the equinoxes, when the sun is
passing from the one hemisphere to the other, and when the magnetic
direction, in the course of its annual variation from east to west, or
vice vers;\, coincides with the direction which is the mean declination
of all the months and of all the hours. The annual variation is obvi-
ously connected with, and dependent on, the earth's position in its orbit
relatively to the sun around which it revolves; as the diurnal variation
is connected with, and dependent on, the rotation of the earth on its axis,
by which each meridian successively passes through every angle of in-
clination to the sun in the round of 24 hours." Sabine, on the Annual
and Diurnal Variations, in the second volume of Observations made at
the Magn. and Meteor ol. Observatory at Toronto, p. xvii — xx. See also
his memoir, On the Annual Variation of the Magnetic Declination at
different periods of the day, in the Philos. Transact, for 1851, pt. f
p. 635, and the Introduction of his Observ. made at the Observatory a£
Hobarton, vol. i, p. xxxiv — xxxvi.

81 Sabine, On the means adopted for determining the Absolute Values,
Secular Change, and Annual Variation of the Terrestrial Magnetic Force,
in the Phil. Transact, for 1850, pt. i, p. 216. In his address to the Asso-
ciation at Belfast (Meeting of the Brit. Assoc. in 1852), he likewise
observes, " that it is a remarkable fact which has been established that
the magnetic force is greater in both the northern and southern hemi-
spheres in the months of December, January, and February, when the
sun is nearest to the earth, than in those of May, June, and July, when
he is most distant from it : whereas, if the effects were due to tempera-
ture, the two hemispheres should be oppositely, instead of similarly,
affected in eacli of the two periods referred to."

G 2

34 COSMOS.

increasing intensity, declination and inclination cannot there-
fore be ascribed to the sun in connection with its thermic
influence.

The annual means deduced from observations at Munich
and Gottingen, have enabled the active director of the Royal
Bavarian Observatory, Professor Lament, to deduce the
remarkable law of a period of 10^ years in the alterations of
declination.83 In the period between 1841 and 1850, the
mean of the monthly alterations of declination attained very
uniformly their minimum in 1843|, and their maximum in
184S|-, Without being acquainted with these European
results, General Sabine was led to the discovery of a periodi-
cally active cause of disturbance from a comparison of the
monthly means of the same years, namely from 1843 to 1848,
which were deduced from observations made at places which
lie almost as far distant from one another as possible (Toronto
in Canada, and Hobarton in Van Diemen's Land). This
cause of disturbance was found by him to be of a purely
cosmical nature, being also manifested in the decennial
periodic alterations in the sun's atmosphere.83 Schwabe,
who has observed the spots upon the sun with more constant
attention than any other living astronomer, discovered (as I
have already elsewhere observed),84 in a long series of years
(from 1826 to 1850), a periodically varying frequency in the
occurrence of the solar spots, showing that their maxima fell
in the years 1828, 1837, and 1848, and their minima in the
years 1833 and 1843. "I have not had the opportunity,"
he writes, " of investigating a continuous series of older
observations, but I willingly subscribe to the opinion that
this period may itself be variable." A somewhat analogous
kind of variability — periods within periods — is undoubtedly
observable in the processes of light of ©ther self-luminous-
suns. I need here only refer to those complicated changes
of intensity, which have been shown by Goodricke and
Argelander to exist in the light of /3 Lyras and Mira Ceti. M

82 Lament, in Poggend. Annalen, Bd. Ixxxiv, s. 579.

83 Sabine, On periodical laws discoverable in the mean effects of the
larger magnetic disturbances, in the Phil. Transact, for 1852, pt. i, p. 121.
Vide supra, p. 75.

84 Cosmos, voL iv, p. 398.

85 Op. cit. voL iii, p. 228.

MAGNETIC VARIATION. &5

If, as Sabine has shown, the magnetism of the sun is
manifested by an increase in the terrestrial force when the
earth is nearest to that luminary, it is the more striking
that, according to Kreil's very thorough investigations of the
magnetic influence of the moon, the latter should hitherto not
have been perceptible, either during the different lunar
phases, or at the different distances assumed by the satellite
in relation to the earth. The vicinity of the moon does not
appear, when compared with the sun, to compensate in this
respect for the smallness of its mass. The main result of
the investigation, in relation to the magnetic influence of the
earth's satellite, which, according to Melloni, exhibits only a
trace of calorification8*, is that the magnetic declination
in our planet undergoes a regular alteration in the course of
a lunar day, during which it exhibits a twofold maximum
and a twofold minimum. Kreil very correctly observes,
"that if the moon exerts no influence on the temperature on
the surface of our earth (which is appreciable by the ordi-
nary means of measuring heat), it obviously cannot in this
way effect any alteration in the magnetic force of the earth ;
but if, notwithstanding, an alteration of this kind is actually
experienced, we must necessarily conclude that it is pro-
duced by some other means than through the moon's heat."
Everything that cannot be considered as the product of a
single force must require, as in the case of the moon, that all
foreign elements of disturbance should be eliminated, in order
that its true nature may be recognized.

Although hitherto the most decisive and considerable
variations in the manifestations of terrestrial magnetism do
not admit of being satisfactorily explained by the maxima
and minima in the variations of temperature, there can be
no doubt that the great discovery of the polar property of
oxygen in the gaseous envelope of our earth will, by a more
profound and comprehensive view of the process of the
magnetic activity, speedily afford us a most valuable assist-
ance in elucidating the mode of origin of this process. It
would be inconceivable if, amid the harmonious co-operation
of all the forces of nature, this property of oxygen and its
modification by an increase of temperature, should not par-

86 Kreil, Einfiuss des Mondes auf die Magnetisdie Declination, 1852,
s. 27, 29, 46.

83 COSMOS.

ticipate in the production and manifestation of magnetic
phenomena.

If, according to Newton's view, it is very probable that
the substances which belong to a group of celestial bodies (to
one and the same planetary system) are for the most part
identical, 8T we may from inductive reasoning conclude that
the electro-magnetic activity is not limited to the gravi-
tating matter on our own planet. To adopt a different
hypothesis would be to limit cosmical views with arbitrary
'dogmatism. Coulomb's hypothesis regarding the influence of
the magnetic sun on the magnetic earth is not at variance
with analogies, based upon the observation of facts.

If we now proceed to the purely objective representation
of the magnetic phenomena, which are exhibited by our
planet on different parts of its surface, and in its different
positions in relation to the central body, we must accurately
distinguish, in the numerical results of our measurements,
the alterations which are comprised within short or very
long periods. All are dependent on one another, and in this
dependence they reciprocally intensify, or partially neutralize
and disturb each other, as the wave-circles in moving fluids
intersect one another. Twelve objects here present them-
selves most prominently to our consideration.

Two magnetic poles, which are unequally distant from the
poles of rotation of the earth, and are situated one in each
hemisphere ; these are points of our terrestrial spheroid at
which the magnetic inclination is equal to 90°, and at which
therefore the horizontal force vanishes.

The magnetic equator, the curve on which the inclination
of the needle = 0°.

The lines of equal declination, and those on which the
declination =. 0 (isogonic lines and lines of no variation).

Tlie lines of equal inclination (isoclinal lines).

The four points of greatest intensity of the magnetic force,
two of unequal intensity in each hemisphere.

The lines of equal terrestrial force (isodynamic lines).

The undulating line which connects together on each
meridian the points of the weakest intensity of the terrestrial
force, and which has sometimes been designated as a dynamic

97 Cosmos, vol. i, pp. 122, 123 ; also vol. iv, p. 568.

MAGNETIC INTENSITY. 87

equator. w This undulating line does not coincide either
with the geographical or the magnetic equator.

The limitation of the zone where the intensity is generally
very weak, and in which the horary alterations of the mag-
netic needle participate, in accordance with the different
seasons of the year, in producing the alternating phenomena
observed in both hemispheres 89.

In this enumeration 1 have restricted the use of the word
pole to the two points of the earth's surface, at which the hori-
zontal force disappears, because, as I have already remarked,
these points, which are the true magnetic poles, but which
by no means coincide with the maxima of intensity, have
frequently been confounded in recent times with the four
terrestrial points of greatest intensity. w Gauss has also
shown that it would be inappropriate to attempt to distinguish
the chord which connects the two points, at which the dip of
the needle = 90°, by the designation of magnetic axis of
the earth91. The intimate connection which prevails between
the objects here enumerated fortunately renders it possible
to concentrate, under three points of view, the complicated
phenomena of terrestrial magnetism in accordance with the
u je manifestations of one active force — Intensity, Incli-
nation, and Declination.

Intensity.

The knowledge of the most important element of terres-
trial magnetism, the direct measurement of the intensity of

88 See Mrs. Somerville's short but lucid description of terrestrial
magnetism, based upon Sabine's works (Physical Geography, vol. ii,
p. 102). Sir James Ross, who intersected the curve of lowest intensity
in his great Antarctic expedition, December, 1839, in 19° S. lat. and
29 ' 13' W. long., and who has the great merit of having first deter-
mined its position in the southern hemisphere, calls it " the equator of
less intensity." See his Voyage to the Southern and Antarctic Regions,
vol. i, p. 22.

89 " Stations of an intermediate character, situated between the
northern and southern magnetic hemispheres, partaking, although iu
opposite seasons, of those contrary features which separately prevail (in
the two hemispheres) throughout the year." Sabine, in the Phil.
Transact, for 1847, pt. i, pp. 53—57.

90 The pole of intensity is not the pole of verticity. Phil. Transact*
for 1846, pt. iii, p. 255.

91 Gauss, Allyem... Theorie des Erdmagnetism**, § 31.

88 COSMOS.

i

the terrestrial force, followed somewhat tardily the know-
ledge of the relations of the direction of this force in
horizontal and vertical planes (declination and inclination).
Oscillations, from the duration of which the intensity is
deduced, were first made an object of experiment towards the
close of the 18th century, and yielded matter for an earnest
and continuous investigation during the first half of the 19th
century. Graham, in 1723, measured the oscillations of his
dipping-needle with the view of ascertaining whether they
were constant,92 and in order to find the ratio which the
force directing them bore to gravity. The first attempt to
determine the intensity of magnetism at widely different
points of the earth's surface, by counting the number of
oscillations in equal times, was made by Mallet in 1769. He
found, with a very imperfect apparatus, that the number of
the oscillations at St. Petersburg (59° 56' N". lat.), and at
Ponoi (67° 4'), were precisely equal93, and hence arose the
erroneous opinion which was even transmitted to Cavendish,
that the intensity of the terrestrial force was the same und-er
all latitudes. Borda, as he has himself often told me, was
prevented, on theoretical grounds, from falling into this error,
and the same had previously been the case with Le Monnier;
but the imperfection of the dipping-needle, the friction which
existed between it and the pivot, prevented Borda (in his
expedition to the Canary Islands in 1776), from discovering
any difference in the magnetic force between Paris, Toulon,
Santa Cruz de Tenerifte, and Goree in Senegambia, over a
space of 35° of latitude. (Voyage de La Perouse, t. i,
p. 162.) This difference was, for the first time, detected with
improved instruments in the disastrous expedition of La
Perouse in the years 1785 and 1787 by Lamanon, who com-
municated it from Macao to the Secretary of the French
Academy. This communication, as I have already stated,
(see p. 61), remained unheeded, and like many others lay
buried in the archives of the Academy.

The first published observations of intensity, which more-

02 Phil. Transact, vol. xxxiii, for 1724—1725, p. 332 ("to try if the
dip and vibrations were constant and regular").

93 Novi Comment. Acad. Scient. Petropol, t. xiv, pro anno 1769, pars 2,
p. 33. See also Le Monnier Lois du Magnetism* comparees aux observa*
tiontf 1776, p. 50.

MAGNETIC INTENSITY. 69

over were instituted at the suggestion of Borda, are those
which I made during my voyage to the tropical regions of
the New Continent between the years 1798 and 1804. The
results obtained at an earlier date (from 1791 to 1794),
regarding the magnetic force, by my friend de Rossel, in the
Indian Ocean, were not printed till four years after my
return from Mexico. In the year 1829 I enjoyed the advan-
tage of being able to prosecute my observations of the mag-
netic intensity and inclination over a space of fully 188°
of longitude from the Pacific eastwards as far as the Chinese
Dzungarei, two-thirds of this portion of the" earth's surface
being in the interior of continents. The differences in the
latitudes amounted to 72° (namely, from 60° N. to 12°
S. Lat.).

When we carefully follow the direction of the closed
isodynamic lines (curves of equal intensity), and pass from
the external and weaker to the interior and gradually stronger
curves, we shall find in considering the distribution of the
magnetic force in each hemisphere, that there are two points,
or foci, of the maxima of intensity, a stronger and a weaker
one, lying at very unequal distances both from the poles of
rotation and the magnetic poles of the earth. Of these four
terrestrial points the stronger, or American, is situated in
the northern' hemisphere94 in 52° 19' N. lat. and in 92° W.
long., whilst the weaker, which is often called the Siberian, is
situated in 70° N. lat. and in 120° E. long, or perhaps a few
degrees less to the eastward. In the journey from Par-
schinsk to Jakutsk, Erman found, in 1829, that the curve of
greatest intensity (1.742) was situated at Beresowski Ostrow
in 117° 51 ' E. long, and 59° 44' K lat. (Erman Magnet. Beob.
s. 172—540; Sabine, in the Phil Transact, jor 1850, pt. i,
p. 218). Of these determinations, that of the American
focus is the more certain, especially in respect to latitude,
while in respect " to longitude it is probably somewhat too
far west." The oval which incloses the stronger northern
focus lies, consequently, in the meridian of the western end
of Lake Superior, between the southern extremity of Hud-

94 In those cases in which individual treatises of General Sabine have
not been specially referred to in these notes, the passages have been
taken from manuscript communications, which have been kindly
placed at my disposal by this learned physicist.

90 COSMOS.

son's Bay and that of the Canadian lake of Winipeg. We
owe this determination to the important land expedition,
undertaken in the year 1843, by Captain Lefroy, of the
Royal Artillery, and formerly director of the Magnetic
Observatory at St. Helena. " The mean of the lem-
niscates which connect the stronger and the weaker focus
appears to be situated north-east of Behring's Straits, and
somewhat nearer to the Asiatic than to the American
focus."

When I crossed the magnetic equator, the line on which
the inclination = 0, between Micuipampa and Caxamarca, in
the Peruvian chain of the Andes, in the southern hemisphere,
in 7° 2' lat. and 78° 48' W. long, and when I observed
that the intensity increased to the north and south of this
remarkable point, I was led from an erroneous generalization
of my own observations, and in the absence of all points of
comparison (which were not made till long afterwards), to
the opinion that the magnetic force of the earth increases
uninterruptedly from the magnetic equator towards both
magnetic poles, and that it was probable that the maximum
of the terrestrial force was situated at these points, that is
to say, where the inclination = 90°. When we first strike
upon the trace of a great physical law, we generally find that
the earliest opinions adopted require subsequent revision.
Sabine,*5 by his own observations, which were made from
1818 to 1822 in very different zones of latitude, and by the
able arrangement and comparison of the numerous oscillation-
experiments with the vertical and horizontal needles, which
of late years have gradually become more general, has shown
that the intensity and inclination are very variously modi-
fied ; that the minimum of the terrestrial force at many
points lies far from the magnetic equator ; and that in the
most northern parts of Canada and in the Arctic regions
around Hudson's Bay from 52° 20' lat. to the magnetic pole
in 70° lat. and from about 92° to 93° W. long, the intensity,
instead of increasing, diminishes. In the Canadian focus of
greatest intensity, in the northern hemisphere, found by
Lefroy, the dip of the needle in 1845 was only 73° 77 and

95 Fifth Report of the British Association, p. 72 ; Seventh Report,
pp. 64 — 68. Contributions to Terrestrial Magnetism No .vii iu the
Phil. Transact, for 1846, pt. iii, p. 254.

MAGNETIC INTENSITY. 91

in both hemispheres we find the maxima of the terrestrial
force coinciding with a comparatively small dip.98

However admirable and abundant are the observations of
intensity which we owe to the expeditions of Sir James Ross,
Moore, and Clerk, in the Antarctic polar seas, there is still
much doubt in reference to the position of the stronger and
weaker focus in the southern hemisphere. The first of these
navigators has frequently crossed the isodynamic curves
of greatest intensity, and from a careful consideration of
his observations, Sabine has been led to refer one of the
foci to 64° S. lat. and 137° 30' E. long. Ross himself, in the
account of his great voyage,97 conjectures that the focus lies
in the neighbourhood of the Terre d'Adelie, discovered by
D'Urville, and therefore in about 67° S. lat. and 140° B. long.
He thought that he had approached the other focus in 60° S.
lat. and 125 W. long.; but he was disposed to place it some-
what further south, not far from the magnetic pole, and
therefore in a more easterly meridian.98

Having thus established the position of the four maxima
of intensity, we have next to consider the relation of the
forces. These data can be obtained from a much earlier

96 Sabine, in the Seventh Report of the Brit. Assoc. p. 77.

9' Sir James Ross, Voyage in the Southern and Antarctic Regions, vol. i,
p. 322. This great navigator, in sailing between Kerguelen's Land and
Van Diemen's Land, twice crossed the curve of greatest intensity, first
in 46° 44' S. lat. 128° 28' E. long, where the intensity increased to
2.034, and again diminished, further east, near Hobarton, to 1.824
(Voy. vol. i, pp. 103 — 104) ; then again, a year later, from January the
1st to April the 3rd, 1841, during which time, it would appear from
the k>g of the Erebus that they had gone from 77° 47' S. lat. 175° 41' E.
long, to 51° 16' S. lat. 136° 50' E. long., where the intensities were
found to be uninterruptedly more than 2.00, and even as much as
2.07 (Phil. Transact, for 1843, pt. ii, pp. 211—215). Sabine's result for
the one focus of the southern hemisphere (64° S.lat. 137° 30' E. long.)
which I have already given in the text, was deduced from observations
made by Sir James Ross between the 19th and 27th of March, 1841
(while crossing the southern isodynamic ellipse of 2.00, about midway
between the extremities of its principal axis), between the southern
latitudes 58° and 64° 26', and the eastern longitudes of 128° 40' and
148° 20' (Contrib. to Terr. Magn. in the Phil. Transact, for 1846, pt. iii,
p. 252).

98 Ross, Voyage, vol. ii, p. 224. In accordance with the instructions
drawn up for the expedition, the two sonthern foci of the maximum of
intensity were conjectured to be in 47° S. lat. 140° E. long, and in CO0
S. lat. 235 E long. (vol. i, p. xxxvi).

92 COSMOS.

source, to which I have already frequently referred, that is to
say, by a comparison with the intensity which I found at a
point of the magnetic equator in the Peruvian chain of the
Andes, which it intersects in 7° 2' lat. and 78° 48' W. long,
or, according to the earliest suggestions of Poisson and Gau&s,
by absolute measurement." If we assume the intensity at
the above indicated point of the magnetic equat or rr 1.000,
in the relative scale, we find from the comparison made be-
tween the intensity of Paris and that of London in the year
1827 (s-ee page 67), that the intensities of these two cities
are 1.348 and 1.372. If we express these numbers in ac-
cordance with the absolute scale they will stand as about
= 10.20 and 10.38, and the intensity, which was assumed to
be 1.000 for Peru, would, according to Sabine, be 7.57 in the
absolute scale, and therefore even greater than the intensity
at St. Helena, which, in the same absolute scale = 6.4. All
these numbers must be subjected to a revision on account of
the different years in which the comparisons were made.
They can only be regarded as provisional, whether they are
reckoned in the relative (or arbitrary) scale or in the absolute
scale, which is to be preferred to the former, but even in
their pres-snt imperfect degree of accuracy they throw con-
siderable light on the distribution of the magnetic force — a
subject which, till within the last half century, was shrouded
in the greatest obs-curity. They afford what is cosmically
of very great importance, historical points of departure for
those alterations in the force, which will be manifested in
future years, probably through the dependence of the earth
upon the magnetic force of the sun, by which it is influenced.
In the northern hemisphere the stronger or Canadian
focus in 52° 19' N. lat. and 92° W. long, has been most satis-
factorily determined by Lefroy. This intensity is expressed
in the relative scale by 1.878, the intensity of London being
1.372, while in the absolute scale it would be expressed by
14.21,100 Even in New York, lat. 40° 42', Sabine found the

99 Phil. Transact, for 1850, pt. i, p. 201; Admiralty Manual, 1849,
p. 16; Erman, Magnet. Beob. s. 437 — 454.

100 On the map of isodynamie lines for North America which occurs
in Sabine's Contributions to Terrestrial Magnetism, No. vii, we find, by
mistake, the value 14.88 instead of 14.21, although the latter, which ia
the true number, is given at page 252 of the text of this memoir.

MAGNETIC INTENSITY. 93

magnetic force not much less (1.803). For the weaker
northern or Siberian focus, 70° lat., 120° E. long., it was
found by Erman to be 1.74 in the relative scale, and by
Hansteen, 1.76, that is to say, about 13.3 in the absolute
scale. The Antarctic expedition of Sir James Ross has
shown us that the difference of the two foci in the southern
hemisphere is probably less than in the northern, but that-
each of the two southern foci exceeds both the northern in
intensity. The intensity in the stronger southern focus,
64° lat., 137° 30' E. long., is at least 2.06 in the relative or
arbitrary scale,1 while in the absolute scale it is 15.60; in
the weaker southern focus, 60° lat., 129° 40' W. long., we find
also, according to Sir James Ross, that it is 1.96 in the arbi-
trary scale and 14.90 in the absolute scale. The greater or
lesser distance of the two foci from one another in the same
hemisphere has been recognised as an important element of
their individual intensity, and of the entire distribution of
the magnetic force. " Even although the foci of the southern
hemisphere exhibit a strikingly greater intensity (namely
15.60 and 14.90 in the absolute scale), than the foci of the
northern hemisphere (which are respectively 14.21 and
13.30), the total magnetic force of the one hemisphere cannot
be esteemed as greater than that of the other."

" The result is, however, totally different when we sepa-
rate the terrestrial sphere into an eastern and western part,
in accordance with the meridians of 100° and 280° E. long,
reckoning from west to east in such a manner that the
eastern or more continental sphere shall enclose South
America, the Atlantic Ocean, Europe, Africa, and Asia,
almost as far as Baikal, whilst the western, which is the
more oceanic and insular, includes almost the whole of North

1 I follow the value given in Sabine's Contributions, No. vii, p. 252a
namely 15.60. We find from the Magnetic Journal of the Erebua
(Phil. Transact, for 1843, pt. ii, pp. 169—172), that several individual
observations, taken on the ice on the 8th of February, 1841, in 77° 47'
S. lat. and 172° 42' W. long, yielded 2.124. The varlue of the intensity
15.60 in the absolute scale would lead us to assume provisionally that
the intensity at Hobarton was 13.51 (Magn. and Meteorol. Obscrv. made
at Hobarton, vol. i, p. 75). This value has, however, lately been slightly
augmented (to 13.56) (vol. ii, xlvi). In the Admiralty Manual, p. 17,
I find the southern focus of greatest intensity changed' to 15.8.

94 COSMOS.

America, the broad expanse of the Pacific, New Holland, and
a portion of Eastern Asia." These meridians lie the one
about 4° west of Singapore, the other 13° west of Cape Horn,
in the meridian of Guayaquil. All four foci of the maxi-
mum of the magnetic force, and even the two magnetic poles
fall within the western hemisphere.3

Adolph Erman's important observation of least intensity
in the Atlantic Ocean, east of the Brazilian province of
Espiritu Santo (20 S. lat., 35 02' W. long.), has been
already mentioned in our Delineation of Nature.4 He found
in the relative scale 0.7062 (in the absolute scale 5.35).
This region of weakest intensity was also twice crossed by
Sir James Ross in his Antarctic expedition6 between 1 9° and
21° S. lat., as well as by Lieutenant Sulivan and Dunlop
in their voyage to the Falkland Islands.6 In his isodynamic
chart of the entire Atlantic Ocean, Sabine has drawn the
curve of least intensity, which Ross calls the equator of less
intensity, from coast to coast. It intersects the West African
shore of Benguela, near the Portuguese colony of Mossamedes,
(15° S. lat.); its summits are situated in the middle of
the ocean in 18° W. long., and it rises again on the Brazilian
coast as high as 20C S. lat. Whether there may not be
another zone of tolerably low intensity (0'97), lying north of
the equator (10° to 12° lat.), and about 20° east of the Phi-
lippines is a question that must be left for future investiga-
tions to elucidate.

I do not think that the ratio which I formerly gave of
the weakest to the strongest terrestrial force requires
much modification in consequence of later investigations.
This ratio falls between 1 : 2^ and 1 : 3, being sorne-

3 See the interesting Map of the World, divided into hemispheres by a
plane coinciding with the meridians of 100 and 280 E. of Greenwich,
exhibiting the unequal distribution of the magnetic intensity in the two
hemispheres, plate v, in the Proceedings of the Brit. Assoc. at Liverpool,
1837, pp. 72 — 74. Erman found that the intensity of the terrestrial
force was almost constantly below 0.76, and consequently very small in
the southern zone between latitudes 24° 25' and 13° 18', and between
the western longitudes of 34° 50' and 32° 44'.

4 Cosmos, vol. i, p. 181.

5 Voyage in the Southern Seasn vol. i, pp. 22, 27 ; vide supra, p. 96.

6 See the Journal of Sulivan and Dunlop, in the Phil. Transact, fof
1840, pt. i, p. 143. They found as the minimum only 0.800.

MAGNETIC INTENSITY. 95

what nearer to the latter number, and the difference of
the data7 arises from the circumstance that in some cases
the minima alone, and in others the minima and maxima
together, have been altered somewhat arbitrarily. Sabine8
has the great merit of having first drawn attention to the
importance of the dynamic equator, or curve of least intensity.
" This curve connects the points of each geographical meri-
dian at which the terrestrial intensity is the smallest.
It describes numerous undulations in passing round the
earth, on both sides of which the force increases with the
higher latitudes of each hemisphere. It in this manner
indicates the limits between the two magnetic hemispheres
more definitely than the magnetic equator, on which the
direction of the magnetic force is vertical to the direction of
gravity. In respect to the theory of magnetism, that which
refers directly to the force itself is of even greater importance
than that which merely refers to the direction of the needle,
its horizontal or vertical position. The curves of the
dynamic equator are numerous, in consequence of their
depending upon forces, which produce four points (foci) of
the greatest terrestrial force, which are unsymmetrical and
of unequal intensity. We are more especially struck in these
inflections with the great convexity in the Atlantic Ocean
towards the South Pole, between the coasts of Brazil and the
Cape of Good Hope."

Does the intensity of the magnetic force perceptibly
decrease at such heights as are accessible to us, or does it
perceptibly increase in the interior of the earth ? The pro-
blem which is suggested by these questions is extremely

7 We obtain 1:2.44 on comparing in the absolute scale St. Helena,
which is 6.4, with the focus of greatest intensity at the south pole,
which is 15.60, and 1:2.47 by a comparison of St. Helena with the
higher southern maximum of 15.8, as given in the Admiralty Manual,
p. 17, and 1 : 2.91 by a comparison in the relative scale of Erman's ob-
servation in the Atlantic Ocean (0.706), with the southern focus (2.06) ;
indeed, even 1:2.95, when we compare together in the absolute scale
the lowest value given by this distinguished traveller (5.35), with the
highest value for the southern focus (15.8). The mean resulting ratio
would be 1 :2.69. Compare for the intensity of St. Helena (6.4 in the
absolute, or 0.845 in the arbitrary scale), the earliest observations of
Fitzroy (0.836), Phil. Transact, for 1847, pt. i, p. 52, and Proceeding of
tfie Meeting at Liverpool, p. 56.

8 See Contrib. to Terrestr. Magnetism, No. vii, p. 256.

90 COSMOS.

complicated in the case of observations which are made
either in or upon the earth, since a comparison of the effect
of considerable heights on mountain journeys is rendered
difficult, because the upper and lower stations are seldom
sufficiently near one another, owing to the great mass of the
mountain, and since further, the nature of the rock and the
penetration of veins of minerals, which are not accessible to
our observation, together with imperfectly understood horary
and accidental alterations in the intensity, modify the results,
where the observations are not perfectly simultaneous. In
this manner we often ascribe to the height or depth alone,
conditions which by no means belong to either. The nume-
rous mines of considerable depth which I have visited in
Europe, Peru, Mexico, and Siberia, have never afforded
localities which inspired me with any confidence.9 Then,
moreover, care should be taken in giving the depths, not to
neglect the perpendicular differences above or below the level
of the sea, which constitutes the mean surface of the earth.
The borings %at the mines of Joachimsthal in Bohemia are up
wards of 2000 feet in absolute depth, and yet they only reach
to a stratum of rock which lies between 200 and 300 feet
above the level of the sea.10 Very different and more favour-
able conditions are afforded by balloon ascents. Gay-Lussac
rose to an elevation of 23,020 feet above Paris ; consequently,
therefore, the greatest relative depth that has been reached
by borings in Europe, scarcely amounts to T\th of this height.
My own mountain observations between the years 1709 and
1806, led me to believe that the terrestrial force gradually
decreases with the elevation, although, in consequence of the
causes of disturbance already indicated, several results are at
variance with this conjectural decrease. I have collected in
a note individual data, taken from 125 measurements of
intensity made in the Andes, in the Swiss Alps, Italy, and
Germany.11 These observations extended from the level of

9 We may ask what kind of error can have led in the coal mines of
Flemi to the result that in the interior of the earth, at the depth of 87
feet, the horizontal intensity had increased 0.001 ? Journal de I'Institut,
1845, Avril, p. 146. In an English mine, which is 950 feet below the
level of the sea, Kenwood did not -find any increase in the intensity
(Brewster, Treatise on Magn. p. 275).

10 Cosmos, vol. i, p. 150.

11 A diminution of the intensity with the height is shown in my

MAGNETIC OBSERVATIONS. 97

the sea to an elevation of 15,944 feet, and therefore to the very
limits of perpetual snow, but the greatest heights did not
afford me the most reliable results. The most satisfactory
were obtained on the steep declivity of the Silla de Caracas
(8638 feet), which inclines towards the neighbouring coasts of
La Guayra ; the Santuario de Nbstra Safiora de Guadalupe,

observations from the comparisons of the Silla de Caracas (8638 feet
above the sea, intensity 1.188), with the harbour of Guayra (height
0 feet, intensity 1.262), and the town of Caracas (height 2648 feet,
intensity 1.209) ; from a comparison of the town of Santa Fe* de Bogota
(elevation 8735 feet, intensity 1.147), with the chapel of Neustra
Senora da Guadalupe (elevation 10,794 feet, intensity 1.127), which
seems to hang over the town like a swallow's nest, perched upon a steep
ledge of rock ; from a comparison of the volcano of Purace (elevation
14,548 feet, intensity 1.077), with the mountain village of Purace
(elevation 8671 feet, intensity 1.087), and with the neighbouring
town of Popayan (elevation 5825 feet, intensity 1.117) ; from a com-
parison of the town of Quito (elevation 9541 feet, intensity 1.067),
with the village of San Antonio de Lulumbamba (elevation 8131
feet, intensity 1.087) lying in a neighbouring rocky fissure directly
under the geographical equator. The oscillation experiments, which I
made at the highest point at which I ever instituted observations of the
kind, namely, at an elevation of 15,944 feet on the declivity of the long
since extinct volcano of Antisana, opposite the Chussulongo, were quite
at variance with this result. It was necessary to make this observation
in a large cavern, and the great increase in the intensity was no doubt
the consequence of a magnetic local attraction of the trachytic rock, as
has been shown by the experiments which I made with Gay-Lussac
within, and on the margin of, the crater of Vesuvius. I found the
intensity in the Cave of Antisana increased to 1.188, while in the neigh-
bouring lower plateau it was scarcely 1.068. The intensity at the
Hospice of St. Gotthard (1.313) was greater than that at Airolo (1.309),
but less than that at Altorf (1.322). Airolo, on the other hand, exceeded
the intensity of the Ursern Lake (1.307). In the same manner Gay-
Lussac and myself found that the intensity was 1.344 at the Hospice of
Mont Cenis, whilst at the foot of the same mountain, at Lans le Bourg,
it was 1.323, and at Turin 1.336. The greatest contradictions were
necessarily presented by the burning volcano of Vesuvius, as we have
already remarked. Whilst in 1805 the terrestrial force at Naples was
1,274, and at Portici 1.288, it rose in the Monastery of St. Salvador to
1.302, whilst it fell in the crater of Vesuvius lower than anywhere else
throughout the whole district, namely, to 1.193. The iron contained in
the lava, the vicinity of magnetic poles, and the heat of the soil, which
probably has the effect of diminishing this force, combined to produce
the most opposite local disturbances. See my Voyage aux Regions
Equinoxiales, t. iii, pp 619 — 626, and Mvm. de la Societe d'Arcueil, t. i,
1807, pp. 17—19.

VOL. V. H

98 COSMOS.

which rises immediately over the town of Bogota, upon the
declivity of a steep wall of limestone rock, with a difference
of elevation amounting to upwards of 2000 feet ; and the
volcano of Purace, which rises 8740 feet above the Plaza
Mayor of the town of Popayan. Kupffer in the Caucasus,13
Forbes in many parts of Europe, Laugier and Mauvais on
the Canigou, Bravais and Martins on the Faulhorn, and
during their very adventurous sojourn in the immediate
vicinity of the summit of Mont Blanc, have certainly observed
that the intensity of the magnetic force diminished with the
height, and this decrease appeared from Bravais's general
consideration of the subject to be more rapid in the Pyrenees
than in the chain of the Alps.13

Quetelet's entirely opposite results, obtained in an excur-
sion from Geneva to the Col de Balme and the Great St.
Bernard, make it doubly desirable for the final and decisive
settlement of so important a question, that observations
should be made at some distance from the surface of the
earth ; and these observations can only be carried on by
means of balloon ascents, such as were employed in 1804, by
Gay-Lussac, first in association with Biot, on the 24th of
August, and subsequently alone on the 16th of September.
Oscillations measured at elevations of 19,000 feet, can how-
ever only afford us certain information regarding the trans-
mission of the terrestrial force in the free atmosphere, when

12 Kupffer' s observations do not refer to the summit of the Elbruz,
but to the difference of height (4796 feet) between two stations, viz. the
bridge of Malya, and the mountain declivity of Kharbis, which unfor
tunately differ considerably in longitude and latitude. Regarding the
doubts which Necker and Forbes have advanced in relation to this result
see Transact, of the Royal Soc. of Edin. vol. xiv, 1840, pp. 23—25.

13 Compare Laugier and Mauvais, in the Comptes rcndi*$, t. xvi, 1843,
p. 1175; and Bravais, Observ. deVIntensite du Magnet isme Terrestre en
France, en Suisse, et en Saroie, in the Annales de Chemie et de Phys
Seme Sfirie, t. xviii. 1846, p. 214; Kreil, Einfluss der Alpen auf die.
Intensitat, in the Denkschriften der Wiener Akad. der Wiss. Mathem.
Naturwiss. Cl. Bd. i, 1850, s. 265, 279, 290. It is very remarkable that
BO accurate an observer as Quetelet should have found, in a tour which
he made in the year 1830, that the horizontal intensity increased with
the height, in ascending from Geneva (where it was 1.080), to the
Col de Balne (where it was 1.091), and to the Hospice of St. Bernard

where it was as high as 1.096). See Sir David Brewster, Treatise on
Uagn. p. 275.

MAGNETIC OBSERVATIONS. 99

care is taken to obtain corrections for temperature in the
needles that are employed both before and after the ascent.
The neglect of such a correction has led to the erroneous
result deducible from Gay-Lussac's experiments, that the
magnetic force remains the same to an elevation of more
than 22,000 feet,14 whilst conversely the experiment showed
a decrease in the force on account of the shortening of the
oscillating needle in the upper cold region.15 Faraday's
brilliant discovery of the paramagnetic force of oxygen must
not be disregarded in the discussion of this subject. This
great physicist shows that in the upper strata of the atmo-
sphere, the decrease in the intensity cannot be sought merely
in the original source of the force, namely the solid earth,
but that it may equally arise from the excessively rarefied
condition of the air, since the quantity of oxygen in a cubic
foot of atmospheric air must differ in the upper and lower
strata. It seems to me, however, that we are not justified
in asbuming more than this — that the decrease of the para-
magnetic property of the oxygenous parts of the atmosphere
which diminish with the elevation and with the rarefac-
tion of the air, must be regarded as a co-operating modifying
cause. Alterations of temperature and density through the
ascending currents of air may further alter the amount of
this influence.10 Such disturbances assume a variable and
specially local character, and they operate in the atmosphere
in the same manner as different kinds of rocks upon the
surface of the earth. With every advance which we may
rejoice in having made in our knowledge of the gaseous
envelope of our planet and of its physical properties, we at the
same time learn to know new causes of disturbance in the
alternating mutual action of forces, which should teach us
how cautiously we ought to draw our conclusions.

The intensity of the terrestrial force, when measured at
definite points of the surface of our planet, has, like all the
phenomena of terrestrial magnetism, its horary as well as its
secular variations. The horary variations were distinctly

14 Annales de Chimie, t. Hi, 1805, pp. 86—87.

15 Arago, in the Annuaire du Bureau des Longitudes pour 1836,
p. 287 ; Forbes, in the Edin. Transact, vol. xiv, 1840, p. 22.

16 Faraday, Exper. Researches in Electricity, 1851, pp. 53, 77, §§ 2881,
2S61.

H 2

100 COSMOS.

recognized by Parry during his third voyage, and also, con«
jointly with him, by Lieutenant Foster (1825) at Port
Bowen. The increase of intensity from morning till evening
in the mean latitudes has been made an object of the most
careful investigation by Christie, 17 Arago, Hansteen, Gauss,
and Kupffer. As horizontal oscillations, notwithstanding
the great improvements which have been made in the present
day in the dipping-needle, are preferable to oscillations of the
latter kind, it is not possible to ascertain the horary varia-
tion of the total intensity without a very accurate knowledge
of the horary variation of the dip. The establishment of
magnetic stations, in the northern and the southern hemi-
sphere, has afforded the great advantage of yielding the
most abundant, and, incomparatively, the most accurate
results. It will be sufficient here to instance two points of
the earth's surface, which are both situated without the
tropics, and almost in equal latitudes on either side of the
equator — namely, Toronto, in Canada, 43° 39' N. lat., and
Hobarton, in Van Diemen's Land, in 42° 53' S. lat., with a
difference of longitude of about 15 hours. The simultaneous
horary magnetic observations belong at the one station to
the winter months, while at the other they fall within the
period of the summer months. While measurements are
made at the one place during the day, they are being simul-
taneously carried on at the other station for the most part
during the night. The variation at Toronto is 1° 33' West ;
at Hobarton it is 9° 57' East ; the inclination and the inten-
sity are similar to one another ; the former is, at Toronto,
about 75° 15' to the north, and at Hobarton about 70° 34' to
the south, whilst the total intensity is 13'90 in the absolute
scale at Toronto, and 13 '5 6 at Hobarton. It would appear
from Sabine's investigation, that these well-chosen stations
exhibit 19 four turning points for the intensity in Canada, and
only two such points for Van Diemen's Land. At Toronto,
the variation in intensity reaches its principal maximum
at 6 P.M., and its principal minimum at 2 A.M. ; a weaker
r; Christie, in the Phil Transact, for 1825, p. 49.

18 Sabine, On Periodical Laws of the Larger Magnetic Disturbances,
in the Phil. Transact, for 1851, pt. i, p. 126, and on the Annnal Varia-
tion of the Magn. Declin. in the PhU. Transact, for 1851. pt. ii, p. 636.

19 Observ. made at the Magn. and Meteorol. Observatory at Toronto,
vol. i (1840- 1842), p. Ixii

MAGNETIC OBSERVATIONS. 101

secondary maximum at 8 A.M., and a weaker secondary
minimum at 10 A.M. The intensity at Hobarton, on
the contrary, exhibits a simple progression from a maxi-
mum between 5 and 6 P.M. to a minimum between 8
and 9 A.M. ; although the inclination there, no less than
at Toronto, exhibits four turning points ao. By a com-
parison of the variations of inclination, with those of the
horizontal force, it has been established that, in Canada,
during the winter months, when the sun is in the southern
signs of the zodiac, the total terrestrial force has a greater
intensity than in the summer months, whilst in Van
Diemen's Land the intensity is greater than the mean annual
value — that is to say, the total terrestrial force — from
October to February, which constitutes the summer of the
southern hemisphere, while it is less from April to August.
According to Sabine,21 this intensity of the terrestrial mag-
netic force is not dependent on differences of temperature,
but on the lesser distance of the magnetic solar body from
the earth. At Hobarton, the intensity during the summer
is 13.574 in the absolute scale, whilst during the winter it fe
13.543. The secular variation of intensity has hitherto been
deduced from only a small number of observations. At
Toronto, it appears to have suffered some decrease between
1845 and 1849, and the comparison of my own observations
with those of Rudberg, in the years 1806 and 1832, give a
similar result for Berlin. 22

20 Sabine, in Magn. and Meteor. Observations at Hobarton, vol. i,
p. Ixviii. " There is also a correspondence in the range and turning
hours of the diurnal variation of the total force at Hobarton and at
Toronto, although the progression is a double one at Toronto and a
single one at Hobarton." The time of the maximum of intensity falls
at Hobarton between 8 and 9 A.M.; whilst the secondary or lesser mini-
mum falls at Toronto about 10 A.M., and consequently the increase and
diminution of the intensity fall within the same hours in accordance
with the time of the place, and not at opposite hours, as is the case
with respect to the inclination and the declination. See, regarding the
causes of this phenomenon, p. Ixix (compare also Faraday, Atmospheric
Magnetism, §§ 3027—3034).

21 Phil. Transact, for 1850, pt. i, pp. 215—217; Magnet. Observ.
at Hobarton, vol. ii, 1852, p. xlvi. See also p. 22 of the present
volume. At the Cape of Good Hope the intensity presents less differ-
ence at opposite periods of the year than the inclination (Magnet.
Observ. made at the Cape of Good Hope, vol. i, 1851, p. lv).

22 See the magnetic part of my work on Asie Centrale, t. iii, p. 442.

102 COSMOB.

Inclination.

The knowledge of the isoclinal curves, or lines of equal
inclination, as well as the more rapid or slower increase of
the inclination by which they are determined, (reckoning
from the magnetic equator where the inclination = 0 to
the northern and southern magnetic pole where the horizontal
force vanishes,) has acquired additional importance in modern
times, since the element of the total magnetic force cannot
be deduced from the horizontal intensity, which requires to
be measured with excessive accuracy, unless we are previously
well acquainted with the inclination. The knowledge of the
geographical position of both magnetic poles is due to the
observations and scientific energy of the adventurous navi-
gator, Sir James Ross. His observations of the northern
magnetic pole were made during the second expedition of
his uncle, Sir John Boss (1829— 1833),23 and of the southern
during the Antarctic expedition under his own command
(1839 — 1843). The northern magnetic pole in 70° 5' lat.,
96° 43' W. long., is 5° of latitude farther from the ordinary
pole of the earth than the southern magnetic pole, 75° 35' lat.,
154°10'E. long., which is also situated farther west from
Greenwich than the northern magnetic pole. The latter be-
longs to the great island of Boothia Felix, which is situated very
near the American continent, and is a portion of the district
which Captain Parry had previously named North Somerset.
It is not far distant from the western coast of Boothia Felix,
near the promontory of Adelaide, which extends into King
William's Sound and Victoria Strait. 24 The southern mag-
netic pole has not been directly reached in the same manner
as the northern pole. On the 17th of February, 1841, the
Erebus penetrated as far as 76° 12' S. lat., and 164° E. long,
As the inclination was here only 88° 40', it was assumed that
the southern magnetic pole was about ] 60 nautical miles
distant. ** Many accurate observations of declination, deter-

23 Sir John Barrow, Arctic Voyages of Discovery, 1846, pp. 521 —
529.

24 The strongest inclination which has as yet been observed in
the Siberian continent, is 82° 16', which was found by Middendorf, on
the river Taimyr, in 74° 17' N. lat, and 95° 40' E. long. (Middend.
Siber. Reise, th. i, s. 194).

25 Qir James Eoss, Voyage to the Antarctic Regions, vol. i, p. 246. "I

MAGNETIC INCLINATION. i03

mining the intersection of the magnetic meridian, render it
very probable that the south magnetic pole is situated in
the interior of the great antarctic region of South Victoria
Land, west of the Prince Albert mountains, which approach
the south pole, and are connected with the active volcano of
Erebus, which is 12,400 feet in height.

The position and change of form of the magnetic equator,
that is to say, the line on which the dip is null, were very
fully considered in the Picture of Nature, Cosmos, vol i.,
p. 176. The earliest determination of the African node
(the intersection of the geographical and magnetic equators)
was made by Sabine36 at the beginning of his pendulum
expedition in 1822. Subsequently, in 1840, the same learned
observer noted down the results obtained by Duperrey,
Allen, Dunlop, and Sulivan, and constructed a chart of the
magnetic equator27 from the west coast of Africa at Biafra,
(4° N. lat. 9° 30' E. long.) through the Atlantic Ocean and
Brazil (16° S. lat., between Porto Seguro and Rio Grande,) to
the point where, upon the Cordilleras, in the neighbourhood
of the Pacific, I saw the northern inclination assume a
southern direction. The African node, as the point of inter-
section of both equators, was situated, in 1837, in 3° E. long.,
while, in 1825, it had been in 6°57/E. long. The secular motion
of the node, turning from the basaltic island of St. Thomas,
which rises to an elevation of more than 7000 feet, was there-
fore somewhat less than half a degree westward in the course
of a year ; after which the line of no inclination turned
towards the north on the African coast, whilst on the Bra-
zilian coast it is inclined southward. The convexity of the
magnetic equatorial curve is persistently turned towards
the south pole, while in the Atlantic Ocean it passes at a
distance of about 16° from the geographical equator. For
the interior of South America, the terra incognita of Mat to

had so long cherished the ambitious hope," says this navigator, '"'to
plant the flag of my country on both the magnetic poles of our globe;
but the obstacles which presented themselves being of so insurniount
able a character was some degree of consolation as it left us no grounds
for self-reproach" (p. 247).

26 Sabine, Pendul. Exper. 1825. p. 476.

27 Sabine, in the Phil. Transact, for 1840, pt. i, pp. 136, 139, 146. I
follow for the progression of the African node the map which is
appended to this treatise.

104 COSMOS.

0 rosso between the large rivers of Xingu, Madera, andUcayle,
we have no observations of the dip until we reach the chain
of the Andes, where, 68 geographical miles east of the shores
of the Pacific, between Montan, Micuipampa, and Caxamarca,
I determined astronomically the position of the magnetic
equator, which rises towards the north-west (7° 2' S. lat., and
78° 46' W. long.) ».

The most complete series of observations which we pos-
sess in reference to the position of the magnetic equator was
made by my old friend, Duperrey, during the years 1823 —
1825. He crossed the equator six times during his voyages
of circumnavigation, and he was enabled to determine this
line by his own observations over a space of 2200.29 Accord-
ing to Duperrey 's chart of the magnetic equator, the two
nodes are situated in long. 5° 50' E. in the Atlantic Ocean,
and in long. 177° 20' E. in the Pacific, between the meri-

-3 I here give, in accordance with my usual practice, the elements of
this not wholly unimportant determination : Micuipampa, a Peruvian
mountain town at the foot of Cerro de Guelgayoc. celebrated for its
rich silver mines, 6° 44' 25" S. lat., 78° 33' 3" W. long., elevation above
the Pacific 11,872 feet, magnetic inclination 0°.42 north (according to the
centesimal division of the circle) ; Caxamarca, a town situated on a
plateau at an elevation of 9362 feet, 7° 8' 38" S. lat., 5h 23' 42" long.,
inclination 0.15 south; Montan, a farm-house (or hacienda), surrounded
by Llama flocks, situated in the midst of mountains, 6° 33' 9" S.
lat., 5h 26' 51" W. long., elevation 8571 feet, inclination 0.70 north;
Tomependa, on the mouth of the Chinchipe, on the river Amazon, in
the province of Jaen de Bracamoros, 5° 31' 28" S. lat., 78° 37' 30" W.
long., elevation 1324 feet, inclination 3°.55 north; Truxillo, a Peru-
vian town on the Pacific, 8° 5' 40" S. lat., 79° 3' 37" W. long., inclina-
tion 2°.15 south. Humboldt, Recueil d'Observ. Astron. (Mvellement
Barometrique et Geode"sique) vol. i, p. 316, No. 242, 244 — 254. For
the basis of astronomical determinations, obtained by altitudes of the
stars and by the chronometer, see the same work, vol. ii, pp. 379 — 391.
The result of my observations of inclination in 1802, in 7° 2' S. lat., and
78° 48' W. long., accords pretty closely by a singular coincidence, and
notwithstanding the secular alteration, with the conjecture of Le
Monnier, which was based upon theoretical calculation. He says, " th»
magnetic equator must be in 7° 40' north of Lima, or at most in 6° 30
S. lat., in 1776"(Zoi's du Magnetisme comparees aux Observations, pt. ii,
p. 59). _

•9 Saigey, Mem sur VEquateur Magnetique d'apres les Observ. du
Capitaine Duperrey, in the Annales Maritimes et Coloniales, Dec. 1833,
t. iv, p. 5. Here it is observed that the magnetic equator is not a curve
of equal intensity, but that the intensity varies in different parts of thia
equator from 1 to 0.867.

THE MAGNETIC EQUATOR. 105

clians of the Fejee and Gilbert Islands. While the magnetic
equator leaves the western coasts of the South American
continent, probably between Punta de la Aguja and Payta,
it is constantly drawing nearer in the west to the geogra-
phical equator, so that it is only at a distance of 2° from it
in the meridian of the group of the Mendana Islands.30
About 10° farther west, in the meridian which passes
through the western part of the Paumotu Islands (Low
Archipelago) lying in 153° 50' E. long., Captain Wilkes
found that the distance from the geographical equator in
1840 was still fully 2°.31 The intersection of the nodes in
the Pacific is not as much as 180° from that of the Atlantic
nodes, that is to say, it does not occur in 174° 10' W. long.,
but in the meridian of the Fejee Islands, situated in about
177° 20' E. long. If, therefore, we pass from the west coast
of Africa, through South America westward, we shall find
in this direction that the distance of the nodes from one
another is about 8^° too great, which is a proof that the
curve of which we are here speaking is not one of the
great circles.

According to the admirable and comprehensive determi-
nations which were made by Captain Elliot from 1846 to
1849, between the meridians of Batavia and Ceylon, and
which coincide in a remarkable manner with those of Jules
de Blosseville (see page 64), it would appear that the
magnetic equator passes through the northern point of
Borneo, and almost due west into the northern point of
Ceylon, in 9° 45' N. lat. The curve of minimum total in-
tensity runs almost parallel to this part of the magnetic
equator,32 which enters the western part of the continent of
Africa, south of the Cape of Gardafui. This important re-
entering point of the curve has been determined with great
accuracy by Rochet d'Hericourt on his second Abyssinian
expedition, from 1842 to 1845, and by the interesting dis-

30 This position of the magnetic equator was confirmed by Erman for
the year 1830. On his return from Kamtscatka to Europe, he found
the inclination almost null at 1° 30' S. lat., 132° 37' W. long.; in 1° 52' S.
lat., 135° 10' W. long.; in 1° 54' lat., in 133° 45' W. long.; in 2° 1' S. lat,,
139° 8' W. long. (Erman, Magnet Beob. 1841, s. 536).

31 Wilkes, United States Exploring Expedition, vol. iv, p. 263.
K Elliot, in the Phil. Transact, for 1851, pt. i, pp. 287—331.

106 COSMOS.

cussion to which his magnetic observations gave rise.33 This
point lies south of Gaubade, between Angolola and Angobar,
the capital of the kingdom of Schoa, in 10° 7' N". lat., and in
41° 13' E. long. The course of the magnetic equator in the
interior of Africa, from Angobar to the Gulf of Biafra, is as
thoroughly unexplored as that in the interior of South
America, east of the chain of the Andes, and south of the
geographical equator. Both these continental districts are
nearly of equal extent, measured from east to west, each
extending over a space of about 80° of longitude, so that we
are still entirely ignorant of the magnetic condition of nearly
one quarter of the earth's circumference. My own observa-
tions of inclination and intensity for the whole of the in-
terior of South America, from Cumana to the Rio Negro, as
well as from Cartagena de Indias to Quito, refer only to the
tropical zone north of the geographical equator, while those
which I made in the southern hemisphere, from Quito as far
as Lima, were limited to the district lying near the western
coast.

The translation of the African node towards the west from
1825 to 1837, which we have already indicated, has been con-
firmed on the eastern coasts of Africa by a comparison of the
inclination-observations made by Pant on, in the year 1776,
with those of Rochet d'Hericourt. The latter observer
found the magnetic equator much nearer the Straits of Bab-el-
Mandeb, namely, 1° south of the island of Socotora, in 8° 40'
"N". lat. There was, therefore, an alteration of 1° 27' lat. for
49 years, whilst the corresponding alteration in the longitude
was determined by Arago and Duperrey to have been 10°
from east to west. The direction of the secular variation of
the nodes of the magnetic equator on the eastern coasts of
Africa, towards the Indian Ocean, was precisely similar to
that on the western coast. The quantity of the motion
must, however, be ascertained from much more accurate
results than we at present possess.

The periodicity of the alterations of the magnetic inclina-
tion, whose existence had been noticed at a much earlier
period, has only been established with certainty and
thorough completeness within the last twelve years, since
the erection of British magnetic stations in both hemispheres.
33 Duperrey, in the Comptes rendus, t. xxii, 1846, pp. 804 — 806.

MAGNETIC INCLINATION. 107

Arago, to whom the theory of magnetism is so largely in-
debted, had indeed recognised, in the autumn of 1827, " that
the dip was greater at 9 A.M. than at 6 P.M., whilst the inten-
sity of the magnetic force, when measured by the oscilla-
tions of a horizontal needle, attained its minimum in the
first, and its maximum in the second period."34 In the

w In a letter from Arago to myself, dated Mayence, 13th of Decem-
ber, 1827, he writes as follows: — "I have definitely proved during the
late Aurorpe boreales, which have been seen at Paris, that this pheno-
menon is always "accompanied by a variation in the position of the hori-
zontal and dipping needles, as well as in intensity. The changes of
inclination have amounted to 1' or 8'. To effect this change, after
allowing for every change of intensity, the horizontal needle must
oscillate more or less rapidly, according to the time at which the obser-
vation is made, but in correcting the results by calculating the imme-
diate effects of the inclination, there still remained a sensible variation
of intensity. On repeating by a new method the diurnal observation of
inclination, on which I was engaged during your late visit to Paris, 1
found a regular variation, not for the means but for each day, which
was greater in the morning at nine than in the evening at six. You
are aware that the intensity, measured ivith the horizontal needle, is on
the contrary at its minimum at the first period, while it attains its
maximum between six and seven in the evening. The total variation
being very small, one might suppose that it was merely due to a
change of iuclination ; and, indeed, the greatest portion of the apparent
variation of intensity depends upon the diurnal alteration of the hori-
zontal component, but, when every correction has been made, there
still remains a small quantity as an indication of a real variation of in-
tensity." In another letter, which Arago wrote to me from Paris on the
20th of March, 1829, shortly before my Siberian expedition, he expressed
himself as follows : — " I am not surprised that you should have found
it difficult to recognise the diurnal change of inclination, of which I
have already spoken to you, in the winter months, for it is only during
the warmer portions of the year that this variation is sufficiently sen-
sible to be observed with a lens. I would still insist upon the fact,
that changes of inclination are not sufficient to explain the change of
intensity, deduced from the observation of a horizontal needle. An
augmentation of temperature, all other circumstances remaining the
same, retards the oscillations of the needles. In the evening, the tem-
perature of my horizontal needle is always higher than in the morning ;
hence the needle must on that account make fewer oscillations in a given
time in the evening than in the morning; in fact it oscillates more fre-
quently than we can account for by the change of inclination, and hence
there must be a real augmentation of intensity from morning till evening
in the terrestrial magnetic force." Later and more numerous observa-
tions at Greenwich, Berlin, St. Petersburg, Toronto, and Hobarton,
have confirmed Arago's assertion (in 1827) that the horizontal intensity

108 COSMOS.

British magnetic stations this opposition and the periodicity
of the horary variation in the dip have been firmly estab-
lished by several thousand regularly prosecuted observations,
which have all been submitted to a careful discussion since
1840. The present would seem the most fitting place to
notice the facts that have been obtained as materials on
which to base a general theory of terrestrial magnetism.
It must, however, first be observed, that if we consider the
periodical variations which are recognised in the three ele-
ments of terrestrial magnetism, we must, with Sabine, dis-
tinguish in the turning hours at which the maxima or
minima occur, two greater, and therefore more important, ex-
tremes, and other slight variations, which seem to be inter-
calated amongst the others, as it were, and which are for the
most part of an irregular character. The recurring move-
ments of the horizontal and dipping needles, as well as the
variation in the intensity of the total force, consequently
present principal and secondary maxima or minima, and
generally some of either type, which therefore constitutes a
double progression with four turning hours (the ordinary
case), and a simple progression with two turning hours, that
is to say, with a single maximum and a single minimum.
Thus, for instance, in Van Diemen's Land, the intensity or
total force exhibits a simple progression, combined with a

was greater in the evening than towards morning. At Greenwich the
principal maximum of the horizontal force was about 6 P.M., the prin-
cipal minimum about 10 A.M. or at noon; at Schulzendorf, near Berlin,
tile maximum falls at 8 P.M., the minimum at 9 A.M.; at St. Petersburg
the max. falls at 8 P.M., the min. at llh. 20m. A.M. ; at Toronto the
max. falls at 4 P.M., the min. at 11 A.M. The time is always rec-
koned according to the true time of the respective places (Airy, Magn.
Observ. at Greenwich for 1845, p. 13 ; for 1846, p. 102 ; for 1847, p. 241;
Riess and Moser, in Poggend. Annalen. Ed. xix, 1830, s. 175 ; Kupffer,
Compterendu Annuel de V Observatoire Centrale Magn. de St. Petersb.
1852, p. 28 ; and Sabine, Magn. Observ. at Toronto, vol. i, 1840 — 1842,
p. xlii). The turning hours at the Cape of Good Hope and at St. Helena,
where the horizontal force is the weakest in the evening, seem to be
singularly at variance, and almost the very opposite of one another
(Sabine, Magn. Obs. at the Cape of Good Hope, p. xl, at St. Helena,
p. 40). Such, however, is not the case further eastward, in other parts
of the great, southern hemisphere. " The principal feature in the
diurnal change of the horizontal force at Hobarton is the decrease of
force in the forenoon and its subsequent increase in the afternoon"
(Sabine, Magn. Obs. at Hobarton, vol. i, p. liv. vol. ii, p. xliii).

MAGNETIC INCLINATION. 109

double progression of the inclination, while at one part of
the northern hemisphere, which corresponds exactly with
the position of Hobarton, namely, Toronto, in Canada, both
the elements of intensity and inclination exhibit a double
progression.3* At the Cape of Good Hope there is only one
maximum and one minimum of inclination. The horary
periodical variations of the magnetic dip are as follows : —

I. Northern Hemisphere.

Greenwich: Maxim. 9 A.M.; minim. 3 P.M. (Airy, Obsero.
in 1845, p. 21 ; in 1846, p. 113 ; in 1847, p. 247). Inclin.
in the last named year about 9 A.M. on an average 68° 59' 3",
but at 3 P.M. it was 68° 58' 6". In the monthly variation,
the maximum falls between April and June and the mini-
mum between October and December.

Paris : Maxim. 9 A.M. ; minim. 6 P.M. This simple pro-
gression from Paris and Greenwich is repeated at the Cape
of Good Hope.

St. Petersburg : Maxim. 8 A.M.; minim. 10 P.M. Varia-
tion of the inclination the same as at Paris, Greenwich, and
Pekin ; less in the cold months, and the maxima more closely
dependent on time than the minima.

Toronto : Principal maxim. 10 A.M. ; principal minim.
4 P.M. ; secondary maxim. 10 P.M.; secondary minim. 6 A.M.
(Sabine, Tor. 1840—1842, vol. i, p. Ixi.)

II. Southern Hemisphere.

Hobarton, Van Diemen's Land : principal minim. 6 A.M.;
principal maxim. 11 . 30. A.M. ; secondary minim. 5 P.M. ; second-
ary maxim. 10 P.M. (Sabine, Hob., vol. i, p. Ixvii.) The incli-
nation is greater in the summer when the sun is in the southern
zodiacal signs, 70° 36'. 74 ; it is smaller in winter when the
sun is in the northern signs, 70°34/.66. The annual mean
taken from the observations of six years gives 70° 36'.01.
(Sabine, Hob., vol. ii, p. xliv.) Moreover the intensity at
Hobarton is greater from October to February than from
April to August, p. xlvi.

Cape of Good Hope : Simple progression, the minim, being
0 h. 34 m. P.M. ; maxim. 8 h. 34 m. P.M., with an exceedingly

85 Sabine, Hobarton, vol. i, pp. Ixvii, Ixix.

110 COSMOS.

small intermediate variation between 7 and 9 A.M. (Sabine,
Carte Obs. 1841—1850, p. liii.)

The phenomena of the turning hours of the maximum of
the inclinations expressed in the time of the place, fall with
remarkable regularity between 8 and 10 A.M. for places in
the northern hemisphere, such as Toronto, Paris, Greenwich,
and St. Petersburg, whilst in like manner the minima of the
turning hours all fall in the afternoon or evening, although
not within equally narrow limits (at 4, 6, and 10 P.M.). It is
so much the more remarkable, that in the course of very
accurate observations made at Greenwich during five years
there was one year, 1845, in which the epochs of the maxima
and minima were reversed. The annual mean of the in-
clinations was for 9 A.M. : 68° 5 6'. 8, and for 3 P.M.: 68° 58M.
"When we compare together the stations of Toronto and
Hobarton, which exhibit a corresponding geographical posi-
tion on either side of the equator, we find that there is at
Hobarton a great difference in the turning hours of the prin-
cipal minimum of inclination (at 4 o'clock in the afternoon
and 6 o'clock in the morning), although such is not the case
in the turning hours of the principal maximum (10 and
1 1. 30 A M.). The period of the principal minimum (6 A.M.) at
Hobarton coincides with that of the secondary minimum at
Toronto. The principal and secondary maxima occur at
both places at the same hours, between 10 and 11. 30 A.M.
and 10 P.M. The four turning hours of the inclination occur
almost precisely the same at Toronto as at Hobarton, only
in a reversed order (4 or 5 P.M., 10 P.M., 6 A.M., and 10 or
11. 30 A.M.) This complicated effect of the internal terres-
trial fo.'rce is very remarkable. If, on the other hand, we
compare Hobarton and Toronto in respect to the order in
whicli the turning hours of the alterations of intensity and
inclination occur, we shall find that at the former place in
the southern hemisphere the minimum of the intensity
follows only 2 hours after the principal minimum of the
inclination, whilst the delay in the maximum amounts to
6 hours, while in the northern hemisphere, at Toronto, the
minimum of intensity precedes the principal maximum of
inclination by 8 hours, whilst the maximum of intensity
differs only by 2 hours from the minimum of inclination.36
36 Total intensity at Hobartou, max. 5h. 30m. P.M., miu. 8h. 30m, A.M.J

MAGNETIC INCLINATION. Ill

The periodicity of inclination at the Cape of Good Hope
does not coincide with that at Hobarton, which lies in the
same hemisphere, nor with any one point of the northern
hemisphere. The minimum of inclination is indeed reached
at an hour at which the needle at Hobarton has very nearly
reached the maximum.

For the determination of the secular variation of the
inclination, it is necessary to have a series of observations
that have not only been conducted with extreme accuracy,
but which have likewise extended over long intervals of time.
Thus for instance, we cannot go with certainty as far back
as the time of Cook's voyages, for although in his third
expedition the poles were always reversed, we frequently
observe differences of 40' to 55' in the observations of this
great navigator and of Bayley on the Pacific Ocean, a dis-
crepancy which may very probably be referred to the imper-
fect construction of the magnetic needle at that time, and to
the obstacles which then prevented its free motion. For
•London we scarcely like to go further back than Sabine's
observation of August 1821, which compared with the
admirable determination made by himself, Sir James Ross
and Fox in May 1838, yielded an annual decrease of 2'.73,
whilst Lloyd with equally accurate instruments, but in a
shorter interval of time, obtained at Dublin, the very accord-
ant result of 2'.38.37 At Paris, where the annual diminution
of inclination is likewise on the decrease, this diminution is
greater than in London. The very ingenious methods sug-
gested by Coulomb for determining the dip, had indeed led
their inventor to incorrect results. The first observation
which was made with one of Le Noir's perfect instruments
at the Paris Observatory, belongs to the year 1798. At that
time I found, after often repeating the experiments conjointly
with the Chevalier Borda 69° 51' ; in the year 1810, in con-
junction with Arago, I found 68° 50'.2, and in the year
1826, with Mathieu, 67° 56'.7. In the year 1841, Arago
found 67° 9', and in the year 1851, Laugier and Mauvais

at Toronto, principal max. 6 P.M., principal min. 2 A.M., secondary mar.
•S A.M., secondary min. 10 A.M. See Sabine, Toronto, vol. i, pp. Ixi, Ixii,
and Hobarton, vol i, p. Ixviii.

37 Saluue, Report on the Isoclinal and Isodynamic Lines in the Bril'uh
Island*, 1839, pp. 61—63.

112 COSMOS.

found 66° 35' : all these observers adopting similar methods
and using similar instruments. This entire period which
extends over more than half a century (from 1798 to 1851)
giyes a mean annual diminution of the inclination at Paris
of 3'. 69. The intermediate periods stood as follows : —

From 1798—1810 at . . . . 5',08

1810—1826 .. .. 3.37

1826—1811 .. .. 3.13

1841—1851 .. .. 3.40

The decrease between 1810 and 1826 has been strikingly,
though gradually retarded ; for an observation which Gay-
Lussac made with extreme care (69° 12') after his return in
1806 from Berlin, whither he had accompanied me after our
Italian expedition, gave an annual diminution of 4 '.87 since
1798. The nearer the node of the magnetic equator approaches
to the meridian of Paris in its secular progression from east
to west, the slower seems to be the decrease, ranging in half
a century from about 5'.08 to 3'.40. Shortly before my
Siberian expedition in April 1829, I laid before the Academy
of Berlin, a memoir, in which I had compared together the
different points observed by myself, and which I believe I
may venture to say, had all been obtained with equal care.38
Sabine more than 25 years after me measured the inclination
and intensity of the magnetic force at the Havanah, which in
respect to these equinoctial regions, affords a very considerable
interval of time, while he also determined the variation of
two important elements. Hansteen, in 1831, gave the
result of his investigations of the annual variation of the
dip in both hemispheres,39 in a very admirable work which
is of a more comprehensive nature than my own.

38 Humboldt, in Poggend. Annalen, Bd. xv, s. 319—336, Bd. xix,
s. 357 — 391, and in the Voyage aux Regions Equinox, t. iii, pp. 616 —
625.

39 Hansteen, Ueber jdlirliche Verdnderung der Inclination, in Poggend.
Ann. Bd. xxi, s. 403 — 429. Compare also, on the iofluence of the pro-
gression of the nodes of the magnetic equator, Sir David Brewster,
Treatise on Magnetism, p. 247. As the great number of observations
made at different stations have opened an almost inexhaustible field of
inquiry in this department of special investigation, we are constantly
meeting with new complications in our search for the laws by which
these forces are controlled. Thus, for instance, in the course of a series

MAGNETIC OBSERVATIONS. 113

Although Sir Edward Belcher's observations for the year
1838, when compared with those I made in 1803 (see p. 73),
along the Western Coast of America, between Lima, Guaya-
quil, and A capulco, indicate considerable alterations in the
inclination (and the longer the intermediate period the
greater is the value of the results), the secular variation of
the dip at other points of the Pacific has been found to be
strikingly slow. At Otaheite, Bayley found in 1773, 29° 43'
and Fitzroy in 1835, 30° 14', whilst Captain Belcher in 1840,
again found 30° 17', and hence the mean annual variation
scarcely amounted, in the course of 67 years, to O'.Sl.40 A
very careful observer, Sawelieff, found in Northern Asia,
22 years after my visit to those regions, in a journey which
he made from Casan to the shores of the Caspian Sea, that
the inclination to the north and south 01 the parallel of 50°
had varied very irregularly.41

Humboldt. Sawelieff.

1829. 1851.

Casan .. 68° 26'.7 .. .. 68° 30'. 8

Saratow.. 64 40.9 .. ..64 48.7

Sarepta . . 62 15 .9 . . . . 62 39 .6

Astrachan 59 58 .3 .. ..60 27.9

For the Cape of Good Hope we now possess an extended
series of observations, which if we do not go further back
than from Sir James Ross and du Petit Thouars (1840) to
Vancouver (1791), may be regarded as of a very satisfactory
nature in respect to the variation of the inclination for nearly
half a century.42

of successive years we see that the dip passes in one of the turning hours
— that of the maximum from a decrease to an absolute increase, whilst
in the turning hour of the minimum, the progressive annual decrease
continued the same. Thus, at Greenwich, the magnetic inclination in
the maximum hour (9 A.M.) decreased in the years 1844 and 1845,
while it increased at the same hour from 1845 to 184P, and continued
in the turning hour of the minimum (3 P.M.) to decrease from 1844 to
1846 (Airy, Magn. Observ. at Greenwich, 1846, p. 113).

40 Phil. Transact, for 1841, pt. i, p. 35.

41 Compare Sawelieff, in the Bulletin Physico-Mathematique de T Acad.
Imp. de St. Petersb. t. x, No. 219, with Humboldt, Asie Centr. t. iii,
p. 440.

42 Sabine, Magn. Observ. at the Cape of Good Hope, vol. i, p. Ixv. If
we may trust to the observations made by Lacaille for the year 1751,

VOL. V. I

114: COSMOS.

The solution of the question whether the elevation of the
soil does in itself exert a perceptible influence on magnetic
dip and intensity,43 was made the subject of very careful
investigation during my mountain journeys in the chain of
the Andes, in the Ural, and Altai. I have already observed,
in the section on Magnetic Intensity, how very few localities
were able to afford any certainty as to this question, because
the distance between the points to be compared together
must be so small as to leave no ground for suspecting that
the difference found in the inclination may be a consequence
of the elevation of the soil, instead of the result of the cur-
vature of the isodynamic and isoclinal lines, or of some great
peculiarity in the composition of the rocks. I will limit
myself to the four results which I thought at the time they
were obtained, showed more decisively than could be done
by observations of intensity, the influence exerted by eleva-
tion in diminishing the dip of the needle.

The Silla de Caracas, which rises almost vertically above
La Guayra, and 8638 feet above the level of the sea, south
of the coast but in its immediate vicinity and north of the
town of Caracas, yielded the inclination of 41°. 90 ; La
Guayra, elevation 10 feet, inclination 4 2°. 20 ; the town of
Caracas, height above the shores of the Bio Guayre, 2648
feet, inclination 42°. 95. (Humboldt, Voy. aux Reg. Equi-
nox., t. i, p. 612.)

Santa .¥6 de Bogota : elevation 8735 feet, inclination
27°. 15 \ the chapel of Nuestra Senora de Guadalupe, built
upon the projecting edge of a rock, elevation 10,794 feet, in-
clination 26°.80.

Popayan : elevation 5825 feet, inclination 23°. 25 ; moun-
tainous village of Purace on the declivity of the volcano,
elevation 8671 feet, inclination 21°. 80 ; summit of the vol-
cano of Purace, elevation 14,548 feet, inclination 20°. 30.

Quito : elevation 9541, inclination 14°. 85 ; San Antonio
de Lulumbamba, where the geographical equator intersects

who, indeed, always reversed the poles, but who made his observations
with a needle which did not move freely, it follows that there has been
an increase in the inclination at the Cape of Good Hope of 3°.08 in
89 years !

43 Arago, in the Annuaire du Bureau des Long, pour 1825, pp. 285
—288.

MAGNETIC OBSERVATIONS. 115

the torrid valley, elevation of the bottom of the valley 8153
feet, inclination 16°. 02. (All the above-named inclinations
have been expressed in decimal parts of a degree.)

It might perhaps be deemed unnecessary, considering the
extent of the relative distances and the influence of the
neighbouring kinds of rock,44 for me to enter fully into the
details of the following observations : the Hospice of St.
Gotthard, 7087 feet, inclination 66° 12' ; compared with
Airolo, elevation 3727 feet, inclination 66° 54', and Altorf,
inclination 66° 55' ; or to notice the apparently contradictory
data yielded by Lans le Bourg, inclination 66° 9', the Hospice
of Mont Cenis, 6676 feet, inclination 66° 22', and Turin 754
feet, inclination 6 6° 3'; or by Maples, Portici and the margin of
the crater of Vesuvius; or by the summit of the Great Mili-
schauer (Phonolith) inclination 67° 53'.5, Teplitz inclination
67° 19'. 5, and Prague inclination GG^iT'.e.44 Simultaneously
with the series of admirable comparative observations pub-
lished with the fullest details of the horizontal intensity,
which were made in 1844 by Bravais, in conjunction with
Martins and Lepileur, and compared at 35 stations, includ-
ing the summits of Mont Blanc (15,783 feet), of the Great St.
Bernard (8364 feet), and of the Faulhorn (8712 feet), the
above-named physicists made a series of inclination experi-
ments on the grand plateau of Mont Blanc (12,893 feet), and
at Chamouni (3421 feet). Although the comparison of these
results showed that the elevation of the soil exerted an in-
fluence in diminishing the magnetic inclination, observations
made at the Faulhorn and at Brienz (1870 feet in eleva-
tion) showed the opposite result of the inclination increasing
with the height. The different investigations on horizontal
intensity and inclination failed to yield any satisfactory
solution of the problem. (Bravais, Sur VIntensite du Mag-
net isme Terrestre en France, en Suisse, et en Savoie, in the
Annales de Chimie et de Physique, 3eme serie, t. xviii, 1846,
p. 225.) In a manuscript report by Borda of his expedition

44 I would again repeat that all the European observations of incli-
nation \vhichhave been given in this page have been reckoned according
to the diyi§ion of the circle into 360 parts, and it is only in those obser-
vations of inclination which I made myself before the month of June,
1804, in the New Continent, that the centesimal division of the arc has
been, adhered to (Voy. aux Regions Equinox., t. iii, pp. 615 — 623).

12

116 COSMOS.

to the Canary Islands, in the year 1776, which is preserved
at Paris in the Depot de la Marine, and which I have been
enabled to consult through the obliging courtesy of Admiral
Rosily, I have discovered that Borda was the first who made
an attempt to investigate the influence of a great elevation
on the inclination. He found that the inclination was 1° 15'
greater at the summit of the Peak of Tenerifie than in the
harbour of Santa Cruz, owing undoubtedly to the local
attractions of the lava, as I have often observed on Vesuvius
and different American volcanoes. (Humboldt, Voy. aux
Regions Eqiiinox., t. i, pp. 116, 277, 288.)

In order to try whether the deep interior portions of the
body of the earth influence magnetic inclination in the same
manner as elevations above the surface, I instituted an ex-
periment during my stay at Freiberg, in July 1828, with all
the care that I could bestow upon it, and with a constant
inversion of the poles ; when I found after very careful in-
vestigation that the neighbouring rock, which was composed
of gneiss, exerted no action on the magnetic needle. The
depth below the surface was 854 feet, and the difference
between the inclination of the subterranean parts of the
mine and those points which lay immediately above it, and
even with the surface, was only 2'. 06 ; but considering the
care with which my experiments were made, I am inclined
to think from the results given for each needle, as recorded in
the accompanying note,*5 that the inclination is greater in

45 In the Churprinz mine at Freiberg, in the mountains of Saxony,
the subterranean point was 133£ fathoms deep, and was observed with
Freiesleben and Reich at 2£ P.M. (temperature of the mine being
60°.08 F.). The dipping needle A showed 67° 37'.4, the needle B
67° 32/.7, the mean of both needles in the mine was 67° 35'.05. In the
open air, at a point of the surface which lies immediately above the
point of subterranean observation, the needle A stood at 11 A.M. at
67° 33'.87 and the needle B at 67° 32'.12. The mean of both needles
in the upper station was 67° 32'.99, the temperature of the air being
60°.44 F., and the difference between the upper and lower result
2'.06. The needle A, which, as the stronger of the two, inspired me
with most confidence, gave even 3'. 53, whilst the influence of the depth
remained almost inappreciable when the needle B only was used (Hum-
boldt, in Poggend. Annal. Bd. xv, s. 326). I have already described in
detail, and elucidated by examples, in Asie Centr. t. iii, pp. 465 — 467,
the uniform method which I have always employed in reading the
azimuth circle in order to find the magnetic meridian by corresponding

MAGNETIC OBSERVATIONS. 117

the Churprinz mine than on the surface of the mountain.
It would be very desirable if opportunities were to present
themselves in cases, where there is evidence that the rock
has not exerted any local influence on the magnet, for care-
fully repeating my experiments in mines, in which, like those
of Valenciana near Guanaxuato in Mexico, the vertical
depth is 1686 feet ; or in English coal mines nearly 1900
feet deep, or in the now closed shaft at Kuttenberg in
Bohemia, 3778 feet in depth.4*

After a violent earthquake at Cumana on the 4th of
November, 1799, 1 found that the inclination was diminished
0°.90, or nearly a whole degree. The circumstances under
which I obtained this result, and which I have elsewhere
fully described, 47 afford no sufficient ground for the suspi-
cion of an error in the observation. Shortly after my arrival
at Cumana I found that the inclination was 43°.53. A few
days before the earthquake, I was induced to begin a long
series of carefully conducted observations in the harbour of
Cumana, in consequence of having accidentally noticed a
statement in an otherwise valuable Spanish work, Mendoza's
Tratado de Navegacion, t. ii, p. 72, according to which it
was erroneously asserted that the hourly and monthly
alterations of inclination were greater than those of varia-
tion. I found between the 1st and 2nd of November that
the inclination exhibited very steadily the mean value of
43°. 65. The instrument remained untouched and properly
levelled on the same spot, and on the 7th of November, and
therefore three days after the great earthquake and when
the instrument had again been adjusted, it yielded 42°. 75.
The intensity of the force, measured by vertical oscillations
was not changed. I expected that the inclination would
perhaps gradually return to its former position, but it re-
mained stationary. In September, 1800, in an expedition of

inclinations, or by the perpendicular position of the needle ; as also to
find the inclination itself on the vertical circle by reversing the bearings
of the needle and by taking the readings at both points, before and after
the poles had been reversed. The position of the two needles has, in
each case, been read off 16 times, in order to obtain a mean result.
Where so small an amount has to be determined, it is necessary to enter
fully into the individual details of the observation.

46 Cosmos, vol. i, p. 148.

47 Humboldt, Voy. aux Regions Equinox, t. i, pp. 515 — 517.

118 COSMOS.

more than 2000 geographical miles on the waters and along
the shores of the Orinoco and the Rio Negro, the same in-
strument, which was one of Borda's, which I had constantly-
carried with me, yielded 42°. 80, showing, therefore, the
same dip as before my journey. As mechanical disturb-
ances and electrical shocks excite polarity in soft iron by
altering its molecular condition, we might suspect a connec-
tion between the influences of the direction of magnetic
currents and the direction of earthquakes ; but carefully as
I observed this phenomenon, of whose objective reality I
did not entertain a doubt in 1799, I have never on any
other occasion, in the many earthquakes which I experienced
in the course of three years at a subsequent period in South
America, noticed any sudden change of the inclination,
which I could ascribe to these terrestrial convulsions, how-
ever different were the directions, in which the undulations
of the strata were propagated. A very accurate and ex-
perienced observer, Erman, likewise found that after an
earthquake at Lake Baikal, on the 8th of March, 1828, there
was no disturbance in the declination48 and its periodic
changes.

Declination.

We have already referred to the historical facts of the
earliest recognition of those phenomena, which depend upon
the third element of terrestrial magnetism, namely, declina-
tion. The Chinese, as early as the 12th century of our era,
were not only well acquainted with the fact of the variation
of a horizontal magnetic needle (suspended by a cotton
thread) from the geographical meridian, but they also
knew how to determine the amount of this variation.
The intercourse which the Chinese carried on with the
Malays and Indians, and the latter with Arab and
Moorish pilots, led to the extensive use of the mariner's
compass amongst the Genoese, Majorcans and Catalans, in
the basin of the Mediterranean, on the west coast of Africa,
and in high northern latitudes ; while the maps, which were
published as early as 1436, even give the variation for dif-
ferent parts of the sea.49 The geographical position of a

48 Erman, Reise um die Erde, Bd. ii, s. 180.

49 See page 52 ; Petrus Peregrine informs a friend that he found the
variation in Italy was 5° east in 1269.

MAGNETIC VARIATION. 119

line of no variation, on which the needle turns to the true
north, — the pole of the axis of the earth— was determined
by Columbus on the 13th of September, 1492, and it did
not escape his notice that the knowledge of the magnetic
declination might serve in the determination of geographical
longitudes. I have elsewhere shewn, from the Admiral's log,
that when he was uncertain of the ship's reckoning, he
endeavoured, on his second voyage, April, 1496, to ascertain
his position by observations of declination. M The horary
changes of variation which were simply recognized as certain
facts by Hellibrand and Father Tachard, at Louvo, in Siam,
were circumstantially and almost conclusively observed by
Graham in 1722. Celsius was the first who made use of
these observations to institute simultaneous measurements
at two widely remote points. 51

Passing to the consideration of the phenomena observed
in the variation of the magnetic needle, we must first notice
its alterations in respect to the different hours of the
night and day, the different seasons of the year and the
mean annual values ; next, in respect to the influence which
the extraordinary, although periodically recurring disturb-
ances, and the magnetic position, north or south of the
equator, exert on these alterations, and finally in respect to
the different lines passing through the terrestrial points at
which the variation is equal, or even null. These linear
relations are certainly most important in respect to the direci

50 Humboldt, Examen. Grit, de VHut. de la Geogr. t. iii, pp. 29, 36.
38, 44 — 51. Although Herrera (Dec. i, p. 23) says that Columbus had
remarked that the magnetic variation was not the same by day and
by night, it does not justify us in ascribing to this great discoverer a
knowledge of the horary variation. The actual Journal of the admira1
which has been published by Navarrete, informs us that from the 17tk
to the 30th of September, 1492, Columbus had reduced everything to a
so-called "unequal movement" of the polar star and the pointers
(Guardas), Examen Grit. t. iii, pp. 56 — 59.

51 See pages 60, 70. The first printed observations for London are
those by Graham, in the Phil. Transact, for 1724 and 1725, vol. xxxijn,
pp. 96 — 107 (An Account of Observations made of the Horizontal Needle
at London, 1722—1723, by Mr. George Graham). The change of the
variation depends " neither upon heat nor cold, diy or moist air.
The variation is greatest between 12 and 4 in the afternoon, and the
least at 6 01 7 in the evening." These however, are not the true turning
hours.

120 COSMOS.

practical application of their results to the ship's reckoning,
and to navigation generally ; but all the cosmical phenomena
of magnetism, amongst which we must place those extraor-
dinary and most mysterious disturbances which often act
simultaneously at very remote distances (magnetic storms),
are so intimately connected with one another, that no single
one of them can be neglected in our attempt gradually to
complete the mathematical theory of terrestrial magnetism.
In the middle latitudes, throughout the whole northern
magnetic hemisphere, (the terrestrial spheroid being as-
sumed to be divided through the magnetic equator) the
north end of the magnetic needle, — that is to say, the end
which points towards the north pole, — is most closely in the
direction of that pole about 8h. 15m. A.M. The needle moves
from east to west, from this hour till about Ih. 45m. P.M., at
which time it attains its most westerly position. This motion
westward is general, and occurs at all places in the northern
hemisphere, whether they have a western variation, as the
whole of Europe, Pekin, .Nertschmsk and Toronto, or an
eastern variation, like Kasan, Sitka in Russian America,
Washington, Marmato (New Grenada), and Payta on the
Peruvian coast. *2 From this most westerly point, at
Ih. 45m. P.M., the magnetic needle continues to retrograde

52 Proofs of this are afforded by numerous observations of George
Fuss and Kowanko, at the observatory in the Greek convent at Pekin,
by Anikin at Nertschinsk, by Buchanan Biddell at Toronto in Canada ;
(all these being places of western variation); by Kupffer and Simonoff
at Kasan ; by Wrangel, notwithstanding the many disturbances from
the Aurora borealis at Sitka, on the north-west coast of America;
by Gilliss at Washington; by Boussingault at Marmato, in South Ame-
rica ; and by Duperrey at Payta, on the Peruvian shores of the Pacific ;
(all these being places with an eastern variation). I would here observe
that the mean declination was 2° 15' 42" west at Pekin (Dec., 1831)
(Poggend. Annalen, Bd. xxxiv, s. 54); 4° 1' 44 "west at Nertschinsk
(Sept., 1832) (Poggend. Op. Git. s. 61); 1° 33' west at Toronto (Novem-
ber, 1847) (see Observ. at the Magnet teal and Meteorological Observatory
at Toronto, vol. i, p. xi, and Sabine, in the Phil. Transact, for 1851,
pt.ii, p. 636), 2° 21' east at Kasan (August, 1828), (Kupffer, Simonoff,
and Erman, Reise um die Erde, Bd. ii, s. 532); 28° 16' east at Sitka
(November, 1829) (Erman, Op. Git. s. 546); 6° 33' east at Marmato
(August, 1828), (Humboldt, in Poggend. Annalen, Bd. xv, s. 331); 8° 56'
east at Payta (August, 1823), (Duperrey, in the Connaissance des Temps
pour 1828,, p. 252). At Tiflis the declination was westerly from 7 A.M.
till 2 P.M. (Parrot, Reise zum Ararat, 1834, Th. ii, s. 58).

MAGNETIC VARIATION. 121

towards the east throughout the whole of the afternoon and
a portion of the night till midnight, or 1 A.M., while it often
makes a short pause about 6 P.M. In the night there is again
a slight movement towards the west, until the minimum or
eastern position is reached at 8h. 15m. A.M. This nocturnal
period which was formerly entirely overlooked, since a gradual
and uninterrupted retrogression towards the east between
Ih. 45m. P.M. and 8h. 15m. A.M. was assumed, had already
been carefully studied by me at Rome, when I was engaged
with Gay-Lussac in observing the horary changes of variation
with one of Prony's magnetic telescopes. As the needle is
generally unsteady as long as the sun is below the horizon,
the small nocturnal motion westward is more seldom and
less distinctly manifested. At those occasions when this
motion was clearly discernible, I never saw it accompanied
by any restlessness of the needle. The needle, during this
small western period, passes quietly from point to point of
the dial, exactly in the same manner as in the reliable diurnal
period, between 8h. 15m. A.M. and Ih. 45m. P.M., and very dif-
ferently from the manner in which it moves during the
occurrence of the phenomenon which I have named a mag-
netic storm. It is very remarkable that when the needle
changes its continuous western motion into an eastern move-
ment, or conversely, it does not continue unchanged for any
length of time, but it turns round almost suddenly, more
especially by day, at the above-named periods, 8h. 15m. A.M.
and Ih. 45m. P.M. The slight motion westward does not
commonly occur until after midnight and towards the early
morning. On the other hand, it has been observed at Berlin,
and during the subterranean observations at Freiberg, as well
as at Greenwich, Makerstoun in Scotland, Washington and
Toronto, soon after 10 or 11 P.M.

The four movements of the needle, which I recognised in
1805,53 have been represented in the admirable collection of
observations made at Greenwich in the years 1845, 1846, and

53 See extracts from a letter, which I addressed to Karsten, from
Eome, June the 22ud, 1805, " On four motions of the magnetic needle,
constituting, as it were, four periods of magnetic ebbing and flowing,
analogous to the barometrical periods." This communication was
printed in Hansteen's Magnetismus der Erde, 1819, s. 459. On the long
disregarded nocturnal alterations of variation, see Faraday, OntheNiyht
Episode, §. 3012—3024.

IZZ COSMOS.

1847, as the results of many thousand horary observations in
the following four turning points,64 namely, the first mini-
mum at 8 A.M.; the first maximum at 2 P.M. ; the second

54 Airy, Magnetic and Meteorological Observations made at Greenwich
(Results, 1845, p. 6, 1846, p. 94, 1847, p. 236). The close correspondence
between the earliest results of the nocturnal and diurnal turning hours,
and those which were obtained four years later, in the admirable obser-
vatories at Greenwich and at Toronto in Canada, is clearly shown by
the investigation made by my old friend, Enke, the distinguished direc-
tor of the observatory at Berlin, between the corresponding observa-
tions of Berlin and Breslau. He wrote as follows on the llth of
October, 1836 : — "In reference to the nocturnal maximum, or the
inflection of the curve of horary variation, I do not think that there
can be a doubt, as, indeed, Dove has also shown from the Freiberg
observations for 1830 (Poggend. Ann. Bd. xix, s. 373). Graphical repre-
sentations are preferable to numerical tables for affording a correct
insight into this phenomenon. In the former, great irregularities at
once attract the attention, and enable the observer to draw a line of
average ; while in the latter the eye is frequently deceived, and indivi-
dual and striking irregularities are mistaken for a true maximum or
minimum. The periods seem to fall regularly at the following turning
hours : —

The greatest eastern declination falls at 8 A.M. 1 max. E.

„ „ western „ „ 1 P.M. 1 min. E.

The secondary or lesser eastern max. 10 P.M. 11 max. E.

„ „ „ western min. 4 A.M. 11 min, E.

The secondary or lesser minimum (the nocturnal elongation westward)
falls, more correctly speaking, between 3 and 5 A.M., sometimes nearer
the one hour, and sometimes nearer the other." I need scarcely ob-
serve that the periods which Enke and I designate as the eastern
minima (the principal and the secondary minimum at 4 A.M.) are named
western maxima in the registers of the English and American stations,
which were established in 1840, and consequently our eastern maxima
(8 A.M. and 10 P.M.) would, in accordance with the same form of expres-
sion, be converted into western minima. In order, therefore, to give a
representation of the horary motion of the needle in its general charac-
ter and analogy in the northern hemisphere, I will employ the terms
adopted by Sabine, beginning with the period of the greatest western
elongation, reckoned according to the mean time of the place : —

Freiberg. Breslau. Greenwich

1829. 1836. 1846-47.

Maximum ,~~ ,-.... 1 P.M. 1 P.M. 2 P.M.

Minimum 1 A.M. 10 P.M. 12 P.M.

Maximum 4 A.M. 4 A.M. 4 A.M.

Minimum ,... SA.M. 8 A.M. 8 A.M.

MAGNETIC VAKIATION. 123

minimum at 12 P.M. or 2 A.M.; and the second maximum at
2 A.M. or 4 A.M. I must here content myself with merely
giving the mean conditions, drawing attention to the fact,

Makerstoun. Toronto. Washington.

1842-43. 1845-47. 1840-42.

Maximum Oh. 40m. 1 P.M. 2 P.M.

Minimum 10 P.M. 10 P.M. 10 P.M.

Maximum 2h. 15m. A.M. 2 A.M. 2 A.M.

Minimum 7h.l5m.A.M. 8 A.M. 8 A.M.

The different seasons exhibited some striking differences at Greenwich.
In the year 1847 there was only one maximum (2 P.M.) and one mini-
mum (12 night) during the winter; in the summer there was a double
progression, but the secondary minimum occurred at 2 A.M. instead of
4 A.M. (p. 236). The greatest western elongation (principal maximum)
remained stationary at 2 P.M. in winter as well as in summer, but the
smaller or secondary minimum fell, in 1846, as usual (p. 94), at about
8 A.M. in the summer, and in winter about 1 2 at night. The mean whiter
western elongation continued without intermission throughout the whole
year between midnight and 2 P.M. (see also for 1845, p. 5). We owe the
erection of the observatory at Makerstoun, Roxburghshire, in Scotland,
to the generous scientific zeal of Sir Thomas Brisbane (see John Allan
Broun, Obs. in Magnetism and Meteorology made at Makerstoun in 1843,
pp. 221 — 227). On the horary diurnal and nocturnal observations of
St. Petersburg, see Kupffer, Compte-rendu Meteor, et Mag. a Mr. de
Brock en 1851, p. 17. Sabine, in his admirable and ingeniously com-
bined graphic representation of the curve of horary declination at
Toronto (Phil. Transact, for 1851, pt. ii, plate 27), shows that there is
a singular period of rest (from 9 to 11 P.M.) occurring before the small
nocturnal western motion, which begins about 11 P.M., and continues
till about 3 A.M. " We find," he observes, " alternate progression and
retrogression at Toronto twice in the 24 hours. In 2 of the 8 quarters
(1841 and 1842) the inferior degree of regularity during the night occa-
sions the occurrence of a triple max. and min.; in the remaining quar-
ters the turning hours are the same as those of the mean of the 2 years."
(Obs. made at the Magn. and Meteor. Observatory at Toronto, in Canada,
vol. i, pp. xiv, xxiv, 183 — 191, and 228; and Unusual Magn. Distur-
bances, pt. i, p. vi.) For the very complete observations made at Wasb-
ington, see Gilliss, Magn. and Meteor. Observations made at Washington,
p. 325 (General .Law). Compare with these Bache, Observ. at the Magn.
and Meteor. Observatory at the Girard College, Philadelphia, made in the
years 1840 to 1845 (3 volumes, containing 3212 quarto pages) vol. i,
p. 709, vol. ii, p. 1285, vol. iii, pp. 2167, 2702. Notwithstanding the
vicinity of these two places (Philadelphia lying only 1° 4' north, and
0* 7' 33" east of Washington), I find a difference in the lesser periods
of the western secondary maximum and secondary minimum. The
former falls about Ih. 30m. and the latter about 2h. 15m. earlier at
Philadelphia.

124 COSMOS.

that the morning principal minimum of 8h. is not changed in
our northern zone by the earlier or later time of sunrise.
At the two solstitial periods, and the three equinoxes, at
which, conjointly with Oltmanns, I watched the horary
variations for 5 to 6 consecutive days and nights, T found
that the eastern turning point remained fixed between
7h. 45m. A.M. and 8h. 15m. A.M. both in summer and ir
winter, and was only very slightly anticipated by the earliei
period at which the sun rose.*6

In the high northern latitudes near the Arctic circle, and
between the latter and the pole of the earth's rotation, the
regularity of the horary declination has not yet been very
clearly recognised, although there has been no deficiency in
the number of very carefully conducted observations regard-
ing this point. The local action of the rocks and the fre-
quency of the disturbing action of the polar light, either in
the immediate vicinity or at a distance, made Lottin hesi-
tate in drawing definite conclusions in reference to these
turning hours, from his own great and careful labours, which
were carried on during the French scientific expedition of
Lilloise in 1836, or from the earlier results, that had been
obtained with much care and accuracy by Lowenorn, in
1786. It would appear that at Reikjavik, in Iceland, 64° 8'
lat,, as well as at Godthaab, on the coast of Greenland,
according to observations made by the missionary, Genge,
the minimum of the western variation fell almost as in the

55 Examples of the slightly earlier occurrence of the turning hours
are given by Lieutenant Gilliss, in his Magn. Observ. of Washington,
p. 328. At Makerstoun, in Scotland (55° 35' N". lat.), variations are
observed in the secondary minimum, which occurs about 9 A.M. in the
first three and the last four months of the year, and about 7 A.M. in the
remaining five months (from April till August); the reverse being the
case at Berlin and Greenwich (Allan Broun, Observ. made at Makers-
toun, p. 225). The idea of heat exerting an influence on the regular
changes of the horary variation, whose minimum falls in the morning
near the time of the minimum of the temperature, as the maximum
very nearly coincides with maximum heat, is most distinctly contra-
dicted by the nocturnal motions of the needle, constituting the second-
ary min. and secondary max. " There are 2 maxima and 2 minima of
variation in the 24 hours, but only one minimum and one maximum of
temperature" (Relshuber, in Poggend. Annalen der Physik und Chemie,
Bd. 85, 1852, s. 416). On the normal motion of the magnetic needle
in Northern Germany, see Dove, Poggend. Annalen, Bd. xix, s. 364 —
374.

MAGNETIC VARIATION. 125

middle latitudes at about 9 or 10 A.M., whilst the maximum
did not appear to occur before 9 or 10 P.M.66 Farther to the
north, at Hammerfest, in Finmark, 70° 40' lat., Sabine found
that the motion of the needle was tolerably regular, as in the
south of Norway and Germany,67 the western minimum being
at 9 A.M. and the western maximum at Ih. 30m. P.M.; he
found it, however, different at Spitzbergen, in 79° 50' lat.,
where the above-named turning hours fell at 6 and at
7h. 30m. A.M. In reference to the Arctic polar archipelago,
we possess an admirable series of observations, made during
Captain Parry's third voyage, in 1825, by Lieutenants Foster
and James Ross, at Port Bowen, on the eastern coast of
Prince Regent's Inlet, 73° 14' N. lat., which were extended
over a period of 5 months. Although the needle passed
twice in the course of 24 hours through that meridian,
which was regarded as the mean magnetic meridian of the
place, and although no Aurora borealis was visible for fully
2 months (during the whole of April and May), the periods
of the principal elongations varied from 4 to 6 hours, and
from January to May, the means of the maxima and minima
of the western variation differed by only Ih.! The quantity
of the decimation rose in individual days from 1° 30' to
6° or 7°, whilst at the turning periods it hardly reaches as
many minutes.88 Not only within the Arctic circle, but
also in the equatorial regions, as, for instance, at Bombay,
18° 56' lat., a great complication is observable in the horary
periods of magnetic variation. These periods may be
grouped into two principal classes, which present great dif-
ferences between April and October on the one hand, and
between October and December on the other, and these are
again divided into two sub- periods, which are very far from
being accurately determined.69

56 Voy. en Islande et en Greenland, execute en 1835 et 1836, sur la
Corv. la Recherche; Physique (1838), pp. 214—225, 358—367.

5? Sabine, Account of the Pendulum Experiments, 1825, p. 500.

53 See Barlow's "Report of the Observations at Port Bowen," in the
Edlnb. New Philos. Journal, vol. ii, 1827, p. 347.

59 Professor Orlebar, of Oxford, former superintendent of the Mag-
netic Observatory of the Island of Colaba, erected at the expense
of the East India Company, has endeavoured to elucidate the com-
plicated laws of the changes of declination in the sub-periods (Ob-
servations made at the Mayn. and Meteor. Observatory at Bombay in

126 COSMOS.

Europeans could not have learnt, from their own expe-
rience, the direction of the magnetic needle in the southern
hemisphere before the second half of the 15th century, when
they may have obtained an imperfect knowledge of it from
the adventurous expeditions of Diego Cam with Martin
Behaim, and Bartholomew Diaz, and Vasco de Gama. The
Chinese, who, as early as the 3rd century of our era, as well
as the inhabitants of Corea and the Japanese Islands, had
guided their course by the compass at sea, no less than by
land, are said, according to the testimony of their earliest
writers, to have ascribed great importance to the south direc-
tion of the magnetic needle, and this was probably mainly
dependent on the circumstance, that their navigation was
entirely directed to the south and south-west. During these
southern voyages, it had not escaped their notice that the
magnetic needle, according to whose direction they steered
their course, did not point accurately to the south pole. We
even know, from one of their determinations, the amount ^ of
the variation towards the south-east, which prevailed during
the 12th century. The application and farther diffusion of
such nautical aids favoured the very ancient intercourse of
the Chinese and Indians with Java, and to a still greater
extent the voyages of the Malay races and their colonisation
of the island of Madagascar.81

1845, Results, pp. 2 — 7. It is singular to find that the position of the
needle during the first period from April to October (western min.
7h. 30m. A.M., max. Oh. 30m. P.M. ; min. 5h. 30m., max. 7 P.M.) coin-
cides so closely with that of Central Europe. The month of October is
a transition period, as the amount of diurnal variation scarcely amounts
to 2 minutes in November and December. Notwithstanding that this
station is situated 8° from the magnetic equator, there is no obvious
regularity in the turning hours. Everywhere in nature, where various
causes of disturbances act upon a phenomenon of motion at recurring
periods (whose duration, however, is still unknown to us), the law by
which these disturbances are brought about often remains for a long
time unexplained in consequence of the perturbing causes either reel-
procally neutralising or intensifying one another.

60 See my Examen Grit, de I'ffist. de la Geogr. t. iii, pp. 34—37.
The most ancient notice of the variation given by Keutsungchy, a writer
belonging to the beginning of the twelfth century, was east J- south.
Klaproth's Lettre sur I' invention de la Boussole, p. 68.

61 On the ancient intercourse of the Chinese with Java, according to
Btatements of Fahian in the Fo-kue-si, see Wilhelin von Huraboldt,
Ueber die Kawi Spracke, Bd. i, s. 16.

MAGNETIC VAKIATION. 127

Although, judging from the present very northern position
of the magnetic equator, it is probable that the town of Louvo
in Siam was very near the extremity of the northern mag-
netic hemisphere, when the missionary father, Guy Tachard,
first observed the horary alterations of the magnetic varia-
tion at that place in the year 1682, it must be remem-
bered, that accurate observations of the horary declina-
tion in the southern magnetic hemisphere were not made
for fully a century later. John Macdonald watched the
course of the needle during the years 1794 and 1795 in Fort
Marlborough, on the south-western coast of Sumatra, as well
as at St. Helena.62 The results which were then obtained
drew the attention of physicists to the great decrease in the
quantity of the daily alterations of variation in the lower
latitudes. The elongation scarcely amounted to 3 or 4
minutes. A more comprehensive and a deeper insight into
this phenomenon was obtained through the scientific expedi-
tions of Freycinet and Duperrey, but the erection of mag-
netic stations at three important points of the southern
magnetic hemisphere, at Hobarton in Van Diemen's Land,
at St. Helena, and at the Cape of Good Hope (where for the
last 10 years horary observations have been carried on for the
registration of the alterations of the three elements of ter-
restrial magnetism in accordance with one uniform method),
afforded us the first general and systematic results. In
the middle latitudes of the southern magnetic hemisphere

62 Phil Transact, for 1795, pp. 340—349, for 1798, p. 397. The result
which Macdonald himself draws from his observations at Fort Marl-
borough (situated above the town of Bencoolen, in Sumatra, 3° 47' S.
lat.), and according to which the eastern elongation was on the increase
from 7 A.M. to 5 P.M., does not appear to me to be entirely justified.
No regular observation was made between noon and 3, 4, or 5 P.M., and
it seems probable, from some scattered observations made at different
times from the normal hours, that the turning hours between the
eastern and western elongation fall as early as 2 P.M., precisely the
same as at Hobarton. We are in possession of declination-observations
made by Macdonald during 23 months (from June, 1794, to June,
1796), and from these I perceive that the eastern variation increases at
all times of the year between 7h. 30m. A.M. till noon, the needle moving
steadily from west to east during that period. There is here no trace
of the type of the northern hemisphere (Toronto), which was observ-
able at Singapore, from May till September; and yet Fort Marlborough
lies in almost the same meridian, although to the south of the geogra-
phical equator, and only 5° 4' distant from Singapore.

128 COSMOS.

the needle moves in a totally opposite direction from that
which it follows in the northern, for while in the south the
needle that is pointed southward turns from east to west be-
tween morning and noon, the northern point of the needle
exhibits a direction from west to east.

Sabine, to whom we are indebted for an elaborate revi-
sion of all these variations, has arranged the horary observa-
tions that were carried on for five years at Hobarton (42° 53'
S. lat., variation 9° 57' east,) and Toronto (43° 39' N. lat.,
variation 1° 33' west), so that we can draw a distinction
between the periods from October to February, and from
April to August, since the intermediate months of March
and September present, as it were, phenomena of transition.
At Hobarton the extremity of the needle which points
northwards exhibits two eastern and two western maxima
of elongation,63 so that in the period of the year from Octo-
ber to February it moves eastward from 8 or 9 o'clock A.M.
till 2 P.M., and then from 2 till 11 P.M., somewhat to the
west, from 11 P.M. to 3 A.M. it again turns eastward, and
from 3 *o 8 A.M. it goes back to the west. In the period
between April and August, the eastern turning hours are
later, occurring at 3 P.M. and 4 A.M., whilst the western turn-
ing hours fall earlier, namely at 10 A.M. and at 11 P.M. In
the northern magnetic hemisphere the motion of the needle
westward from 8 A.M. till 1 P.M. is greater in the summer
than in the winter, whilst in the southern magnetic hemi-
sphere, where the motion has an opposite direction between
the above-named turning hours, the quantity of the elon-
gation is greater when the sun is in the southern than when
it is in the northern signs.

The question which I discussed seven years ago in the
Picture of Nature,64 whether there may not be a region of
the earth, probably between the geographical and magnetic
equators, in which there is no horary variation (before the
return of the northern extremity of the needle to an oppo-
site direction of variation in the same hours), is one which

63 Sabine, Magn. Observ. made at Hobarton, vol. i (1841 and 1842),
pp. xxxv ; 2, 148 ; vol. ii (1843—1845), pp. iii— xxxv, 172—344. See
also Sabine, Obs. made at St. Helena, and in Phil. Transact, for 1847,
pt. i, p. 55, pi. iv, and Phil. Transact, for 1851, pt. ii, p. 36, pi. xxvii.

64 Cosmos, vol. i, p. 176.

MAGNETIC INTENSITY. 129

it would seem from recent experiments, and more especially
since Sabine's ingenious discussions of the observations made
at Singapore (1° 11' K lat.), at St. Helena (15° 56' S. lat.),
and at the Cape of Good Hope (33° 56' S. lat.), must be an-
swered in the negative. No point has hitherto been dis-
covered, at which the needle does not exhibit a horary
D'otion, and since the erection of magnetic stations, the im-
portant and very unexpected fact has been evolved, that
there are places in the southern magnetic hemisphere, at
which the horary variations of the dipping needle alter-
nately participate in the phenomena (types) of both
hemispheres. The island of St. Helena lies very near the
line of weakest magnetic intensity, in a region where this
line divaricates very widely from the geographical equator
and from the line of no inclination. At St. Helena, the
movement of the end of the needle which points to the
north is entirely opposite in the months from May to Sep-
tember from the direction which it follows in the analogous
hours from October to February. It has been found after five
years' horary observations, that during the winter of the
southern hemisphere, in the above-named periods of the
year, while the sun is in the northern signs, the northern
point of the needle has the greatest eastern variation at
7 A.M., from which hour, as in the middle latitudes of Europe
and North America, it moves westward till 10 A.M. and re-
mains very nearly stationary until 2 P.M. At other parts of
the year, on the other hand, namely from October till
February, (which constitutes the summer of the southern
hemisphere and when the sun is in the southern signs and
therefore nearest to the earth) the greatest western elonga-
tion of the needle falls about 8 A.M., showing a movement
from west to east until noon, precisely in accordance with
the type of Hobarton (42° 53 S. lat.)," and of other districts
of the middle parts of the southern hemisphere. At the
time of the equinoxes, or soon afterwards, as for instance in
March and April, as well as in September and October, the
course of the needle fluctuates on individual days, showing
periods of transition from one type to another, from that of
the northern to that of the southern hemisphere.66

*•' Sabine, Observations made at the Magn. and Meteor. Observatory at
St. Helena in 1840- -1845, vol. i, p. 30, and in the Phil. Transact, for

VOL. V. K

130 COSMOS.

Singapore lies a little to the north of the geographical
equator, between the latter and the magnetic equator, which,
according to Elliot, coincides almost exactly with the curve
of lowest intensity. According to the observations which
were made at Singapore every two hours during the years
1841 and 1842, Sabine again finds the St. Helena types in
the motion of the needle from May to August and from
November to February ; the same occurs at the Cape of
Good Hope, which is 34° distant from the geographical and
still more remote from the magnetic equator, and where
the inclination is 53° south and the sun never reaches the
zenith.66 We possess the published borary observations made

1847, pt. i, pp. 51 — 56, pi. iii. The regularity of this opposition in the
two divisions of the year, the first occurring between May and Sep-
tember (type of the middle latitudes in the northern hemisphere),
and the next between October and February (type of the middle lati-
tudes in the southern hemisphere), is graphically and strikingly mani-
fested when we separately compare the form and inflections of the
curve of horary variation in the portions of the day intervening be-
tween 2 P.M. and 10 A.M., between 10 A.M. and 4 P.M., and between
d P.M. and 2 A.M. Every curve above the line which indicates the mean
declination has an almost similar one corresponding to it below it
(vol. i, pi. iv, the curves A A and BB). This opposition is perceptible
even in the nocturnal periods, and it is still more remarkable, that
while the type of St. Helena and of the Cape of Good Hope is found to
be that belonging to the northern hemisphere, the same earlier occur-
rence of the turning hours which is observed in Canada (Toronto) is
noticed in the same months at these two southern points. Sabine,
Olserv. at Hobarton, vol. i, p. xxxvi.

66 Phil. Transact, for 1847, pt. i, pp. 52, 57, and Sabine, Observations
made at the Magn. and Meteor. Observatory at the Cape of Good Hope,
1841 — 1846, vol. i, p. xii — xxiii, pi. iii. See also Faraday's ingenious
views regarding the causes of those phenomena, which depend upon
the alternations of the seasons, in his Experiments on Atmospheric
Magnetism, § 3027 — 3068, and on the analogies with St. Petersburg,
§ 3017. It would appear that the singular type of magnetic declina-
tion, varying with the seasons, which prevails at the Cape of Good
Hope, St. Helena, and Singapore, has been noticed on the southern
shores of the Red Sea by the careful observer, d'Abbadie (Airy, On the
Present State of the Science o/ Terrestrial Magnetism, 1850, p. 2). " It
results from the present position of the four points of maximum of
intensity at the surface of the earth," observes Sabine, "that the im-
portant curve of the relatively, but not absolutely, weakest intensity in
the Southern Atlantic Ocean should incline away from the vicinity of
St. Helena, in the direction of thj southern extremity of Africa. The
astronomico-geographical position of this southern extremity, where the
eun remains throughout the whole year north of the zenith, affords a

MAGNETIC DISTURBANCES. 131

at the Cape for six years, from May to September, according
to which, almost precisely as at St. Helena, the needle moves
westward till 1 1 h. 30 m. A.M. from its extreme eastern posi-
tion (7h. 30m. A.M.), while from October to March it moves
eastward from 8h. 30m. A.M. to Ih. 30m. and 2 P.M. The
discovery of this well-attested, but still unexplained and
obscure phenomenon, has more especially proved the import-
ance of observations continued uninterruptedly from hour to
hour for many years. Disturbances which, as we shall soon
have occasion to show, have the power of diverting the
needle either to the eastward or westward for a length of
time, would render the isolated observations of travellers
uncertain.

By means of extended navigation and the application of
the compass to geodetic surveys, it was very early noticed
that at certain times the magnetic needle exhibited an ex-
traordinary disturbance in its direction, which was frequently
connected with a vibratory, trembling and fluctuating mo-
tion. It became customary to ascribe this phenomenon to
some special condition of the needle itself, and this was
characteristically designated by French sailors Taffolemeni de
V aiguille, and it was recommended that une aiguille affolee
should be again more strongly magnetised. Halley was cer-
tainly the first who inferred that polar light was a magnetic
phenomenon — a statement CT which he made on the occasion

principal ground of objection against de la Rive's thermal explanation
(Annales de Chimie et de Physique, t. xxv, 1849, p. 310) of the pheno-
menon of St. Helena here referred to, which, although it seems at first
sight apparently abnormal, is nevertheless entirely in accordance with
established law, and is found to occur at other points." See Sabine, in
the Proceedings of the Royal Society, 1849, p. 821.

6' Halley, Account of the late surprising appearance of Lights in the
Air, in the Phil. Transact, vol. xxix, 1714 — 1716, No. 347, pp. 422 —
428. Halley's explanation of the Aurora boi-ealis is unfortunately con-
nected with the fantastic hypothesis which had been enounced by him
twenty-five years earlier, in the Phil. Transact, for 1693, vol. xvii,
No. 195, p. 563, according to which there was a luminous fluid in th^
hollow terrestrial sphere lying between the outer shell which we inhabit
and the inner denser micleus, which is also inhabited by human beings.
These are his words : — "In order to make that inner globe capable of
being inhabited, there might not improbably be contained some lumi-
nous medium between the balls, so as to make a perpetual day below."
Since the outer shell of the earth's crust is far less thick in the region
of the poles of rotation (owing to the compression produced at tho.-j

K 2

132 COSMOS.

of his being invited by the Royal Society of London to ex-
plain the great meteor of the 6th of March, 1716, which was
seen in every part of England. He says, " that the meteor
is analogous with the phenomenon, which Gassendi first
designated in 1621 by the name of Aurora borealis"
Although in his voyages for the determination of the line
of variation, he advanced as far south as 52°, yet we learn
from his own confession, that he had never seen a northern,
or southern polar light before the year 1716, although the
latter, as I can testify, is visible in the middle of the tropical
zone of Peru. Halley, therefore, does not appear from his
own observation to have been aware of the restlessness of the
needle, or of the extraordinary disturbances and fluctuations
which it exhibits at the periods of visible, or invisible north-
ern or southern polar lights. Olav Hiorter and Celsius at
Upsala were the first who, in the year 1741, and therefore
before Halley's death, confirmed by a long series of measure-
ments and determinations the connection, which he had
merely conjectured to exist between the appearance of the
Aurora borealis and a disturbance in the normal course of the
needle. This meritorious investigation led them to enter
into an arrangement for carrying on systematic observations
simultaneously with Graham in London, while the extra-
ordinary disturbances of variation, observed on the appear-
ance of the Aurora, were made subjects of special investiga-
tion by Wargentin, Canton, and Wilke.

The observations which I had the opportunity of making,
conjointly with Gay-Lussac, in 1805, on the Monte Pincio
at Rome, and more especially the investigations suggested by
these observations, and which I prosecuted conjointly with
Oltmanns during the equinoctial and solstitial periods of

parts) than at the equator, the inner luminous fluid (that is, the mag-
netic fluid), seeks at certain periods, more especially at the times of the
equinoxes, to find itself a passage in the less thick polar regions through
the fissures of rocks. The emanation of this fluid is, according to
Halley, the phenomenon of the northern light. When iron filings are
etrewn over a spheroidal magnet (a terella), they serve to show the
direction of the luminous coloured rays of the Aurora. ' ' As each one
sees his own rainbow, so also the Corona appears to every observer to be
at a different point" (p. 424). Eegarding the geognostic dreams of an
intellectual investigator, who displayed such profound knowledge in all
his magnetic and astronomical labours, see Cosmos, vol. i, p. 163.

MAGNETIC DISTURBANCES. 133

the years 1806 and 1807, in a large isolated garden at Berlin,
by means of one of Prony's magnetic telescopes, and of a
distant tablet-signal, which admitted of being well illumi-
nated by lamp-light, showed me that this element of terres-
trial activity (which acts powerfully at certain epochs, and
not merely locally, and which has been comprehended under
the general name of extraordinary disturbances), is worthy,
on account of its complicated nature, of being made the sub-
ject of continuous observation. The arrangement of the
signal and the cross wires in the telescope, which was sus-
pended in one instance to a silken thread and in another to
a metallic wire, and attached to a bar magnet, enclosed in a
large glass case, enabled the observer to read off to 8" in the
arc. As this method of observation allowed of the room in
which the telescope and the attached bar-magnet stood. beinsj
left unilluminated by night, all suspicion of the action of
currents of air was removed, and those disturbances avoided,
which otherwise are apt to arise from the illumination of the
scale in variation compasses, provided with microscopes,
however perfect they may otherwise be. In accordance with
the opinion then expressed by me that " a continuous unin-
terrupted hourly and half-hourly observation (Observatio
Perpetua) of several days and nights was greatly to be pre-
ferred to isolated observations extending over many months,"
we continued our investigations for 5, 7, and even 1 1 days
and nights consecutively,68 during the equinoctial and solsti-
tial periods — the importance of such observations at these
times being admitted by all recent observers. We soon per-
ceived that, in order to study the peculiar physical character
of these anomalous disturbances, it was not sufficient to de-
termine the amount of the alteration of the variation, but
that the numerical degree of disturbance of the needle must
be appended to each observation by obtaining the measured
elongation of the oscillations. In the ordinary horary course
of the needle, it was found to be so quiet that in 1500 re-
's When greatly fatigued by observing for many consecutive nights,
Professor Oltmanns and myself were occasionally relieved by very
trustworthy observers, as, for instance, by Mampel, the geographer
Friesen, the skilful mechanician Nathan Mendelssohn, and our great
geognosist, Leopold von Buch. It has always afforded me pleasure
to record the names of those who have kindly assisted me in my
labours.

134

COSMOS.

suits, deduced from 6000 observations, made from the middle
of May, 1806, to the end of June, 1807, the oscillation gene-
rally fluctuated only from one-half of a graduated interval to
the other half, amounting therefore only to 1' 12"; in indivi-
dual cases, and often when the weather was very stormy and
much rain was falling, the needle appeared to be either per-
fectly stationary, or to vary only 0.2 or 0.3 of a graduated
interval, that is to say, about 24" or 28". But on the occur-
rence of a magnetic storm, whose final and strongest mani-
festation is the Aurora borealis, the oscillations were either in
some cases only 14' and in others 38' in the arc, each one
being completed in from 1^- to 3 seconds of time. Fre-
quently, on account of the magnitude and inequality of the
oscillations, which far exceeded the scale parts of the tablet
in the direction of one or both of its sides, it was not pos-
sible to make any observation.69 This, for instance, was the

fi9 The month of September, 1806, was singularly rich in great mag-
netic disturbances. By way of illustration, I will give the following
extracts from my journal : —

Sept. 1806, from 4h. 36m. A.M. till 5h. 43m. A.M.

If-

f-

4h. 40m. „ 7h. 2m.

3h. 33m. „ 6h. 27m.

3h. 4m. „ 6h. 2m.

2h. 22m. „ 4h. 30m.

2h. 12m. „ 4h. 3m.

Ih. 55m. „ 5h. 27m.

Oh. 3m. „ Ih. 22m.

The disturbance last referred to was very small, and was succeeded by
the greatest quiet, which continued throughout the whole night, aud
until the following noon.

f£ Sept. 1806, from lOh. 20m. P.M. till llh. 32m. P.M.

This was a small disturbance, which was succeeded by great calm
until 5h. 6m. A.M. 3T° Sct.S 1806, about 2h. 46m. A.M. a great but
short magnetic storm, followed by perfect calm. Another equally great
magnetic disturbance about 4h. 30m. A.M.

The great storm of ff September had been preceded by a still
greater disturbance from 7h. 8m. till 9h. llm. P.M. In the following
winter months there was only a very small number of storms, and these
could not be compared with the disturbances during the autumnal
equinox. I apply the term great storm to a condition in which the
needle makes oscillations of from 20 to 38 minutes, or passes beyond all
the scale parts of the segment, or when it is impossible to make any
observation. In small storms, the needle makes irregular oscillations of
from 5 to 8 minutes.

MAGNETIC DISTUKBANCES. 135

case for long and uninterrupted periods during the night
of the 24th September, 1806, lasting on the first occasion
from 2h. Om. to 3h. 32m. A.M., and next from 3h. 57m.
to 5h. 4m. A.M.

In general, during unusual or larger magnetic disturbances
(magnetic storms), the mean of the arc of the oscillations
exhibited an increase either westward or eastward, although
with irregular rapidity, but in a few cases, extraordinary
fluctuations were also observed, even when the variation
was not irregularly increased or decreased, and when the
mean of the oscilli 'ions did not exceed the limits apper-
taining to the normal position of the needle at the given
time. We saw, after a relatively long rest, sudden motions
of very unequal intensity, describing arcs of from 6' to 15',
either alternating with one another or abnormally inter-
mixed, after which the needle would become suddenly sta-
tionary. At night, this mixture of total quiescence and
violent perturbation without any progression to either side
was very striking.70 One special modification of the motion,

"° Arago, during the ten years in which he continued to make care-
ful observations at Paris (till 1829), never noticed any oscillations with-
out a change in the variation. He wrote to me as follows, in the course
of that year : — " I have communicated to the Academy the results of
our simultaneons observations. I am surprised to notice the oscilla-
tions which the dipping needle occasionally exhibited at Berlin during
the observations of 1806, 1807, and of 1828—1829, even when the mean
declination was not changed. Here (at Paris) we never experience any-
thing of the kind. The only time at which the needle exhibits violent
oscillations is on the occurrence of an Aurora borealis, and when its
absolute direction has been considerably disturbed ; and even then, the
disturbances of direction are most frequently unaccompanied by any
oscillatory movement." The condition here described is, however, en-
tirely opposite to the phenomena which were observed at Toronto
(43° 91' N.lat.) during the years 1840 and 1841; and which correspond
accurately with those manifested at Berlin. The observers at Toronto
have paid so much attention to the nature of the motion that they
indicate whether the vibrations and shocks are " strong" or "slight,"
and characterise the disturbances in accordance with definite and
uniform subdivisions of the scale, following a fixed and uniform nomen-
clature. Sabine, Days of Unusual Magn. Disturbances, vol. i, pt. i,
p. 46. Six groups of successive days (146 in all) are given from the
two above-named years in Canada, which were marked by very strong
shocks, without any perceptible change in the horary declination.
Such groups (see op. cit. pp. 47, 54, 74, 88, 95, 101), are designated as
" Times qf Observations at Toronto, at which the magnetometers were dii'

136 COSMOS.

which I must not pass without notice, consisted in the very
rare occurrence of a vertical motion, a kind of tilting motion,
an alteration of the inclination of the northern point of the
needle, which was continued for a period of from 15 to 20
minutes, accompanied by either a very moderate degree of
horizontal vibration or by the entire absence of this move-
ment . In the careful enumeration of all the secondary condi-
tions which are recorded in the registers of the English obser-
vatories, I have only met with three references to " constant
vertical motion, the needle oscillating vertically,"71 and these
three instances occurred in Van Diemen's Land.

The periods of the occurrence of the greater magnetic
storms fell, according to the mean of my observations in
Berlin, about 3 hours after midnight, and generally ceased
about 5 A.M. We observed lesser disturbances during the
daytime, as, for instance, between 5 and 7 P.M., and fre-
quently on the same days of September, during which violent
storms occurred after midnight, when, owing to the magni-
tude and rapidity of the oscillations, it was impossible to read
them off or to estimate the means of their elongation. I
soon became so convinced of the occurrence of magnetic
storms in groups during several nights consecutively, that I
acquainted the Academy at Berlin with the peculiar nature
of these extraordinary disturbances, and even invited my
friends to visit me at predetermined hours, at which I hoped
they might have an opportunity of witnessing this pheno-
menon, and in general I was not deceived in my anticipa-

turbed, but the mean readings were not materially changed." The changes
of variation were also nearly always accompanied by strong vibrations
at Toronto during the frequent Aurora boreales ; in some cases these
vibrations were so strong as entirely to prevent the observations from
being read off. We learn, therefore, from these phenomena, whose
further investigation we cannot too strongly recommend, that although
momentary changes of declination which disturb the needle may often
be followed by great and definite changes of variation (Younghusband,
Unusual Disturbances, pt. ii, p. x), the size of the arc of vibration in no
respect agrees with the amount of the alteration in the declination ; that
in very inconsiderable changes of variation the vibrations may be very
strong, while the progressive motion of the needle towards a western or
eastern declination may be rapid and considerable, independently of any
vibration ; and further, that these processes of magnetic activity assume
a special and different character at different places.
N Unusual Disturb, vol. i, pt. i, pp. 69, 101.

MAGNETIC DISTURBANCES. 137

tions.78 Kupffer, during his travels in the Caucasus in 1829,
and at a later period, Kreil, in the course of the valuable
observations which he made at Prague, were both enabled
to confirm the recurrence of magnetic storms at the same
hours.73

The observations which I was enabled to make during the
year 1806, at the equinoctial and solstitial periods, in refer-
ence to the extraordinary disturbances in the variation, have
become one of the most important acquisitions to the theory of
terrestrial magnetism, since the erection of magnetic stations
in the different British colonies (from 1838 to 1840), through
the accumulation of a rich harvest of materials, which have
been most skilfully elaborated by General Sabine. In the
results of both hemispheres this talented observer has sepa-
rated magnetic disturbances, according to diurnal and noc-
turnal hours, according to different seasons of the year, and
according to their deviations eastward or westward. At
Toronto and Hobarton the disturbances were twice as fre-
quent and strong by night as by day,74 and the same was the
case in the oldest observations at Berlin ; exactly the reverse
of what was found in from 2600 to 3000 disturbances at
the Cape of Good Hope, and more especially at the island of
St. Helena, according to the elaborate investigation of Cap-

72 This was at the end of September, 1806. This fact, which was
published in Poggendorflfs Annalen der Physilc, Bd. xv (April, 1829),
s. 330, was noticed in the following terms : — " The older horary obser-
vations which I made conjointly with Oltmanns, had the advantage
that at that period (1806 and 1807), none of a similar kind had beeii
prosecuted either in France or in England. They gave the nocturnal
maxima and minima ; they also showed how remarkable magnetic
storms could be recognised, which it is often impossible to record, owing
to the intensity of the vibrations, and which occur for many nights
consecutively at the same time, although no influence of meteorological
relations has hitherto been recognised as the inducing cause of the
phenomena." The earliest record of a certain periodicity of extraordi-
nary disturbances was not, therefore, noticed for the first time in the
year 1839. Report of the Fifteenth Meeting of the British Association at
Cambridge, 1845, pt. ii, p. 12.

73 Kupffer, Voyage au Mont Elbruz dans le Caucase, 1829, p. 108.
" Irregular deviations often recur at the same hour and for several days
consecutively."

74 Sabine, Unusual Disturb, vol. i, pt. i, p. xxi, and Younghusband,
On Periodical Laws in the Larger Magnetic Disturbances, in the
Transact, for 1853, pt. i, p. 173.

138 COSMOS.

tain Younghusband. At Toronto the principal disturbances
generally occurred in the period from midnight to 5 A.M. ; it
was only occasionally that they were observed as early as from
10 P.M. to midnight, and consequently they predominated by
night at Toronto, as well as at Hobarton. After having
made a very careful and ingenious investigation of the 3940
disturbances at Toronto, and the 3470 disturbances at
Hobarton, which were included in the cycle of 6 years (from
1843 to 1848), of which the disturbed variations constituted
the ninth and tenth parts, Sabine was enabled to draw the
conclusion75 that " the disturbances belong to a special kind
of periodically recurring variations, which follow recognisable
laws, depend upon the position of the sun in the ecliptic and
upon the daily rotation of the earth round its axis, and,
further, ought no longer to be designated as irregular
motions, since we may distinguish in them, in addition to a
special local type, processes which affect the whole earth."
In those years in which the disturbances were more frequent
at Toronto, they occurred in almost equal numbers in the
southern hemisphere at Hobarton. At the first-named of
these places these disturbances were, on the whole, doubly as
frequent in the summer, namely from April to September, as in
the winter months, from October to March. The greatest
number fell in the month of September, in the same manner as
at the autumn equinox in my Berlin observations of 1806.T6
They are more rare in the winter months in all places ; at

75 Sabine, in the Phil. Transact, for 1851, pt. i, pp. 125—127. " The
diurnal variation observed is in fact constituted by two variations
superposed upon each other, having different laws, and bearing different
proportions to each other in different parts of the globe. At tropical
stations the influence of what have been hitherto called the irregular
disturbances (magnetic storms), is comparatively feeble ; but it is other-
wise at stations situated as are Toronto (Canada) and Hobarton (Van
Diemen's Island), where their influence is both really and proportion-
ally greater, and amounts to a clearly recognisable part of the whole
diurnal variation." We find here, in the complicated effect of simul-
taneous but different causes of motion, the same condition which has
been so admirably demonstrated by Poisson in his theory of waves
(Annales de Chimie et de Physique, t. vii, 1817, p. 293). " Waves of
different kinds may cross each other in the water as in the air, where
the smaller movements are superposed upon each other." See Lamont's
conjectures regarding the compound effect of a polar and an equatorial
wave, in Poggend. Annalen, Bd. Ixxxiv. s. 583.

<6 See p. 134.

MAGNETIC DISTURBANCES 139

Toronto they occur less frequently from November till
February, and at Hobarton from May till August. At St.
Helena and at the Cape of Good Hope the periods, at which
the sun crosses the equator, are characterised, according to
Younghusband, by a very decided frequency in the disturb-
ances.

The most important point, and one which was also first
noticed by Sabine in reference to this phenomenon, is the
regularity with which, in both hemispheres, the disturbances
occasion an augmentation in the eastern or western variation.
At Toronto, where the declination is slightly westward
(1° 33'), the progression eastward in the summer, that is,
from June till September, preponderated over the progression
westward during the winter (from December till April), the
ratio being 411 : 290. In like manner, in Van Diemen's
Land, taking into account the local seasons of the year, the
winter months (from May till A.ugust) are characterised by
a strikingly diminished frequency of magnetic storms.77
The co-ordination of the observations obtained in the course
of 6 years at the two opposite stations, Toronto and Hobar-
ton, led Sabine to the remarkable result that, from 1843 to
1848, there was in both hemispheres not only an increase in
the number of the disturbances, but also (even when, in order
to determine the normal annual mean of the daily variation,
3469 storms were excluded from the calculation,) that the
amount of total variation from this mean gradually progressed
during the above-named five years from 7 '.65 to 10'.5S.
This increase was simultaneously perceptible, not only in
the amplitude of the declination, but also in the inclination
and in the total terrestrial force. This result acquired addi-
tional importance from the confirmation and generalisation
afforded to it by Lament's complete treatise (September,
1851) "regarding a decennial period, which is perceptible in
the daily motion of the magnetic needle." According to the
observations made at Gottingen, Munich, and Kremsmun-
ster,78 the mean amplitude of the daily declination attained its

77 Sabine, in the Phil. Transact, for 1852, pt. ii, p. 110 (Younghusband,
op. cit. p. 169).

<s According to Lamont and Relshuber, the magnetic period is
10 years 4 months, so that the amount of the mean of the diurnal
motion of the needle increases regularly for 5 years, and decreases for

140 COSMOS.

minimum between 1843 and 1844, and its maximum from
1848 to 1849. After the decimation has thus increased for 5
years it again diminishes for a period of equal length, as is
proved by a series of exact horary observations, which go back
as far as to a maximum in 1786^-.7* In order to discover a
general cause for such a periodicity in all three elements of
telluric magnetism, we are disposed to refer it to cosmical
influences. Such a connection is indeed appreciable, accord-
ing to Sabine's conjecture, in the alterations which take place
in the photosphere, that is to say, in the luminous gaseous
envelopes of the dark body of the sun.80 According to the
investigations which were made throughout a long series of
years by Schwabe, the period of the greatest and smallest
frequency of the solar spots entirely coincides with that
which has been discovered in magnetic variations. Sabine
first drew attention to this coincidence in a memoir which
he laid before the Royal Society of London, in March, 1852.
" There can be no doubt," says Schwabe, in the remarks
with which he has enriched the astronomical portion of the
present work, "that, at least from the year 1826 to 1850,
there has been a recurring period of about 10 years in the
appearance of the sun's spots, whose maxima fell in the
years 1828, 1837, and 1848, and the minima in the years
1833 and 1843."81 The important influence exerted by the
sun's body, as a mass, upon terrestrial magnetism is confirmed
by Sabine in the ingenious observation, that the period at
which the intensity of the magnetic force is greatest, and the
direction of the needle most near to the vertical line, falls,
in both hemispheres, between the months of October and

the same length of time; on which account the winter motion (the
amplitude of declination) is always twice as small as the summer motion
(see Lament, Jahresbericht der Sternwarte zu Milnchenfur 1852, s. 54 —
60). The Director of the Observatory at Berne, Rudolph Wolf, finds
"by a much more comprehensive series of operations, that the period of
magnetic declination which coincides with the frequency of the solar
spots, must be estimated at 11.1 years.

79 See page 75.

80 Sabine, in the Phil. Transact, for 1852, pt. i, pp. 103, 121. See
the observations made in July, 1852, by Rudolph Wolf, above reierred
to in page 76 of the present volume ; also the very similar conjectures
of Qautier, which were published very nearly at the same time in the
BibliotMque l/niverselle de GenZve, t. xx, p. 189.

81 Cosmos, vol. iv, p. 397- 400.

MAGNETIC DISTURBANCES. 141

February ; that is to say, precisely at the time when the
earth is nearest to the sun, and moves in its orbit with the
greatest velocity.82

I have already treated in the Picture of Nature83 of the
simultaneity of many magnetic storms, which are transmitted
for thousands of miles and indeed almost round the entire
circumference of the earth, as on the 25th of September,
1841, when they were simultaneously manifested in Canada,
Bohemia, the Cape of Good Hope, Van Diemen's Land, and
Macao ; and I have also given examples of those cases, in
which the perturbations were of a more local kind, passing
from Sicily to Upsala, but not from Upsala farther north in
the direction of Alten and Lapland. In the simultaneous
observations of declination which were instituted by Arago
and myself in 1829 at Berlin, Paris, Freiberg, St. Peters-
burg, Casan, and Nikolajew, with the same Gambey's instru-
ments, individual perturbations of a marked character were
not transmitted from Berlin as far as Paris, and not on any
one occasion to the mine at Freiberg, where Eeich was mak-
ing a series of subterranean observations on the magnet.
Great variations and disturbances of the needle simultan-
eously with the occurrence of the Aurora borealis at Toronto
certainly occasioned magnetic storms in Kerguelen's Land,
but not at Hobarton. When we consider the capacity for
penetrating through all intervening bodies, which distin-
guishes the magnetic force, as well as the force of gravity
inherent in all matter, it is certainly very difficult to form a
clear conception of the obstacles which may prevent its trans-
mission through the interior of the earth. These obstacles
are analogous to those which we observe in sound-waves, or
in the waves of commotion in earthquakes, in which certain

82 Sabine, in the Phil. Transact, for 1850, pt. i, p. 216. Faraday,
Exper. Researches on Electricity, 1851, pp. 56, 73, 76, § 2891, 2949,
2958.

83 Cosmos, vol. i, p. 185 ; Poggend. Annalen, Bd. xv, s. 334, 335 ;
Sabine, Unusual Disturb, vol. i, pt. i, pp. xiv — xviii; where tables are
given of the simultaneous storms at Toronto, Prague, and Van Diemen's
Land. On those days in which the magnetic storms were the most
marked in Canada (as, for instance, on the 22nd of March, the 10th of
May, the 6th of August, and the 25th of September, 1841), the same
phenomena were observed hi the southern hemisphere in Australia.
See also Edward Belcher, in the Phil. Transact, for 1843, p. 133.

112 COSMOS.

spots which are situated near one another never experience
the shocks simultaneously.84 Is it possible that certain mag-
netic intersecting lines may by their intervention oppose all
further transmission ?

We have here described the regular and the apparently
irregular motions presented by horizontally suspended
needles. If by an examination of the normal recurring-
motion of the needle we have been enabled from the mean
numbers of the extremes of the horary variations to ascer
tain the direction of the magnetic meridian, in which the
needle has vibrated equally to either side, from one solstice
to another, the comparison of the angles which the magnetic
meridian describes at different parallels with the geographi-
cal meridian has led in the first place to the knowledge of
lines of variation of strikingly heterogeneous value (Andrea
Bianco, in 1436, and Alonzo de Santa Cruz, cosmographer
to the Emperor Charles V., even attempted to lay down
these lines upon charts) ; and more recently to the success-
ful generalization of isogonic curves, lines of equal variation,
which British seamen have long been in the habit of grate-
fully designating by the historical name of Halleys lines.
Among the variously curved and differently arranged closed
systems of isogonic lines, which are sometimes almost parallel,
and more rarely re-enter themselves so as to form oval
closed systems, the greatest attention in a physical point
of view is due to those lines, on which the variation is null,
and on both sides of which variations of opposite denomina-
tions prevail, which increase unequally with the distance.85
I have already elsewhere shown how the first discovery
made by Columbus on the 13th of September, 1492, of a
line of no variation in the Atlantic Ocean, gave an impetus
to the study of terrestrial magnetism, which, however, con-
tinued for two centuries and a half to be directed solely to
the discovery of better methods for obtaining the ship's
reckoning.

However much the higher scientific education of mariners
in recent times and the improvement of instruments and
methods of observation have extended our knowledge of

84 Cosmos, voL i, p. 208.

85 Op. cit. vol. i, pp. 187—189; vol. ii, pp. 657 — 659 and pp. 52 —CO
of the present volume.

LINES OF NO VARIATION. 143

individual portions of lines of no variation in Northern
Asia, in the Indian Archipelago and the Atlantic O^ean,
we have still to regret, that in this department of o?ir
knowledge, where the necessity of cosmical elucidation is
strongly felt, the progress has been tardy and the results
deficient in generalization. I am not ignorant that a large
number of observations of accidental crossings of lines of no
variation have been noted down in the logs of various ships,
but sve are deficient in a comparison and co-ordination of
the materials, which cannot acquire any importance in re-
ference to this object or in respect to the position of the
magnetic equator, until individual ships shall be despatched
to different seas for the sole purpose of uninterruptedly fol-
lowing these lines throughout their course. Without a
simultaneity in the observations, we can have no history of
terrestrial magnetism. I here merely reiterate a regret
which I have often previously expressed.86

86 At very different periods, once in 1809, in my Recueil d'Observ.
Astron. vol. i, p. 368, and again, in 1839, when, in a letter addressed to
the Earl of Minto, then First Lord of the Admiralty, a few days before
the departure of Sir James Ross on his Antarctic expedition, I endea-
voured more fully to develope the importance of the proposition ad-
vanced in the text (see Report of the Committee of Physics and Meteor, of
the Royal Soc. relative to the Antarctic Exped. 1840, pp. 88 — 91). " In
order to follow the indications of the magnetic equator or those of the
lines of no variation, the ship's course must be made to cross the lines 0
at very small distances, the bearings being changed each time that obser-
vations of inclination or of declination show that the ship has deviated
from these points. I am well aware that, in accordance with the com-
prehensive views of the true basis for a general theory of terrestrial mag-
netism, which we owe to Gauss, a thorough knowledge of the horizon-
tal intensity, and the choice of the points at which the three elements of
declination, inclination, and total intensity have all been simultaneously
measured, suffice for finding the value of ^- (Gauss, § 4 and 27), and
that these are the essential points for future investigations; but the
sum total of the small local attractions, the requirements of steering
ships, the ordinary corrections of the compass, and the safety of navi-
gation continue to impart special importance to the knowledge of the
position, and to the movements of the periodic translation of lines of no
variation. I here plead the cause of these various requirements, which
are intimately connected with the interests of physical geography."
Many years must still pass before seamen can be enabled, to guide the
ship's course by charts of variation, constructed in accordance with the
theory of terrestrial magnetism (Sabine, in the Phil. Transact, for 1849,
pt. ii, p. 204), and the wholly objective view directed to actual observa-

1 44 COSMOS.

According to the facts which we already generally know
concerning the position of lines of no variation, it would
appear that instead of the four meridian systems which were
believed at the end of the 16th century to extend from pole
to pole,87 there are probably three very differently formed
systems of this kind, if by this name we designate those
groups in which the line of variation does not stand in any
direct connection with any other line of the same kind, or
cannot, in accordance with the present state of our know-
ledge, be regarded as the continuation of any other line. Of
these three systems which we will separately describe, the
middle, or Atlantic, is limited to a single line of no varia-
tion, inclining from SS.E. to NN.W. between the parallels
of 65° south and 67° north latitude. The second system,
which lies fully 150° farther east, occupying the whole of
Asia and Australia, is the most extended, and most compli-
cated of all, if we merely take into account the points at
which the line of no variation intersects the geographical
equator. This system rises and falls in a remarkable manner,
exhibiting one curvature directed southward and another

tion, which I would here advocate, would, if it led to periodically-
repeated determinations, and consequently to expeditions prosecuted
simultaneously by land and sea, in accordance with some preconcerted
plan, give the double advantage of, in the first place, yielding a direct
practical application and affording us a correct knowledge of the annual
progressive movement of these lines ; and secondly, of supplying many
new data for the further development of the theory enounced by Gauss
(Gauss, § 25). It would, moreover, greatly facilitate the accurate deter-
mination of the progression of the two lines of no inclination and no vari-
tion, if landmarks could be established at those points, where the lines
enter or leave continents at stated intervals, as, for instance, in the

years 1850, 1875, 1900 In expeditions of this kind, which

would be similar to those undertaken by Halley, many isoclinal and
isogonic systems would necessarily be intersected before the lines of no
declination and no inclination could be reached, and by this means the
horizontal and total intensities might be measured along the coasts, so
that several objects would thus be simultaneously attained. The views
which I have here expressed are, I am happy to find, supported by a
very great authority in nautical questions, viz. Sir James Ross. (See his
Voyage in the Southern and Antarctic Regions, vol. i, p. 105.)

87 Acosta, Historia de las Jndias, 1590, lib. i, cap. 17. I have already
considered the question whether the opinion of Dutch navigators re-
garding the existence of four lines of no variation may not, through the
differences between Bond and Beckborrow, have had some influence on
Halley 'a theory of four magnetic poles (Cosmos, vol. ii, p 658)

MAGNETIC VARIATION. 14/5

northward ; indeed it is so strongly curved at its north-
eastern extremity that the line of no variation forms an
ellipse, surrounding those lines which rapidly increase in
variation from without inwards. The most westerly and
the most easterly portions of this Asiatic curve of no varia-
tion, incline like the Atlantic line from south to north, and
in the space between the Caspian Sea and Lapland even from
SS.E. to NN.W. The third system, that of the Pacific,
which has been least investigated, is the smallest of all, and
lying entirely to the south of the geographical equator forms
almost a closed oval of concentric lines, whose variation is
opposite to that which we observe in the north-eastern part
of the Asiatic system, and decreases from without inwards.
If we base our opinion upon the magnetic declination ob-
served on the coast, we find that the African continent88 only
presents lines which exhibit a western variation of from 6°
to 29° ; for according to Purchas, the Atlantic line of no
variation left the southern point of Africa (the Cape of Good
Hope) in the year 1605, inclining further from east to west.
The possibility, that we may discover in some part of Central
Africa an oval group of concentric lines of variation, decreas-
ing to 0°, and which is similar to that of the Pacific, can
neither be asserted or denied on any sure grounds.

The Atlantic portion of the American curve of no varia-
tion was accurately determined in both hemispheres for the
year 1840, by the admirable investigations of General Sabine
who employed 1480 observations, and duly took into account
the secular changes. It passes in the meridian of 70° S. lat.,
and about 19° W. long./9 in a NN.W. direction, to about

w In the interior of Africa, the isogonic line of 22° 15' W. is espe-
cially deserving of careful cosmical investigation, as being the interme-
diate line between very different systems, and as proceeding (accord-
ing to the theoretical views of Gauss), from the Eastern Indian Ocean,
straight across Africa on to Newfoundland. The very comprehensive
plan of the African expedition, conducted by Eichardson, Earth, and
Ovenveg, under the orders of the British Government, may probably
lead to the solution of such magnetic problems.

sa Sir James Ross intersected the curve of no variation in 61* 30' S.
lat. and 27° 10' W, long. ( Voyage to the Southern Seas, vol. ii, p. 357).
Captain Crozier found the variation in March, 1843, 1° 38' in 70° 43' S.
lat. and 21° 28' \V. long., and he was therefore very near the line of no
variation. See Sabine, On the Magn. Declination in the Atlantic Ocecv*
for 1840, in the Phil. Transact, for 1849, pt. ii, p. 233,

VOL, V. t

146 COSMOS.

3° east of Cook's Sandwich Land, and to about 9° 30' east
of South Georgia ; it then approaches the Brazilian coast,
which it enters at Cape Frio 2° east of Rio Janeiro and tra-
verses the southern part of the New Continent no farther
than 0° 36' S. lat., where it again leaves it somewhat to the
east of Gran Para, near Cape Tigloca on the Rio do Para,
one of the secondary outlets of the Amazon, crossing the
geographical equator in 47° 44' W. long., then skirting along
the coast of Guiana at a distance of eighty-eight geogra-
phical miles as far as 5° N. lat., and afterwards following the
arc of the small Antilles as far as the parallel of 18°, and
finally touching the shore of North Carolina near Cape
Lookout, south-east of Cape Hattaras in 34° 50' N. lat.,
74° 8' W. long. In the interior of North America, the
curve follows a north-western direction as far as 41° 30' N.
lat., 77° 38' W. long., towards Pittsburgh, Meadville, and
Lake Erie. We may conjecture that it has advanced very
nearly half a degree farther west since 1840.

The Australo-Asiatic curve of no variation (if according
to Erman we consider the part which rises suddenly from
Kasan to Archangel and Russian Lapland as identical with
the part in the sea of Molucca and Japan) can scarcely be
followed as far as 62° in the southern hemisphere. This
starting point lies farther west from Van Diemen's Land than
had hitherto been conjectured, and the three points, at which
Sir James Ross crossed the curve of no variation on his Ant-
arctic voyage of discovery in 1840 and 1841,90 are all situated
in the parallels of 62°, 54°. 30, and 46°, between 133° and
135° 40' E. long. ; and therefore mostly in a meridian-like
direction running from south to north. In its further course,
the curve crosses Western Australia from the southern coast
of Nuyts' Land about 103 W. of Adelaide to the northern
coast near Vansittart river and Mount Cockburn, from
whence it enters the sea of the Indian Archipelago in a region
of the world, in which the inclination, declination, total in-
tensity, and the maximum and minimum of the horizontal
force were investigated by Captain Elliot from 1846 to 1848,
with more care than has been done in any other portion of
the globe. Here the line passes south of Flores and through

* Sir James Ross, Op. dt. vol. i, pp. 104, 310, 317.

MAGNETIC VARIATION. 147

the interior of the small Sandal-wood Island,91 in a direct
east and west direction from about 120° 30' to 93° 30' E
long., as had been accurately demonstrated sixteen years
before by Barlow. From the last named meridian it ascends
towards the north-west in 9° 30' S. lat., judging by the posi-
tion in which Elliot followed the curve of 1° east variation
to Madras. We are not able here to decide definitely whether,
crossing the equator in about the meridian of Ceylon, it-
enters the continent of Asia between the Gulf of Cambay and
Guzurat, or further west in the Bay of Muscat,92 and whether,
therefore, it is identical93 with the curve of no variation,
which appears to advance southward from the basin of
the Caspian Sea ; or whether, as Erman maintains, it may
not curve to the eastward, and rising between Borneo and
Malacca, reach the Sea of Japan,94 and penetrate into Eastern

91 Elliot, in the Phil. Transact, for 1851, pt. i, p. 331, pi. xiii. The
long and narrow small island from which we obtain the sandalwood
(tschendana, Malay and Java, tschandana, Sanscrit, fsandel, Arab).

92 According to Barlow, and the chart of Lines of Magnetic Declina-
tions computed according to the theory of Mr. Gauss, in the Report of the
Committee for the Antarctic Expedition, 1840. According to Barlow the
line of no variation proceeding from Australia enters the Asiatic Con-

'tinent at the Bay of Cambay, but turns immediately to the north-east,
across Thibet and China, near Thaiwan (Formosa), from whence it
enters the Sea of Japan. According to Gatiss, the Australian line
ascends merely through Persia, past Nishnei-Nowgorod to Lapland.
This great geometrician regards the Japan and Philippine line of no
variation, as well as the closed oval group in Eastern Asia, as entirely
independent of the line belonging to Australia, the Indian Ocean,
Western Asia, and Lapland.

93 I have already elsewhere spoken of this identity, which is based upon
my own declination-observations in the Caspian Sea, at Uralsk on the
Jaik, and in the Steppe of Elton Lake (Asie Centrale, t. iii, pp. 458 — 461).

94 Adolf Erman's Map of the Magnetic Declination, 1827 — 1830.
Elliot's chart shows, however, most distinctly that the Australian curve
of no variation does not intersect Java, but runs parallel with, and at a
distance of 1° 30' latitude from the southern coast. Since, according
to Erman, although not according to Gauss, the Australian line of no
variation between Malacca and Borneo enters the Continent through
the Japanese Sea, proceeding to the closed oval group of Eastern Asia,
on the northern coast of the Sea of Ochotsk (59° 30' N. lat.), and again
descends through Malacca, the ascending line can only be 11° distant
from the descending curve ; and according to this graphical representa-
tion, the Western Asiatic line of no variation (from the Caspian Sea to
llussian Lapland) would be the shortest and most direct prolongation
of the part descending from north to south.

L 2

14fc COSMOS.

Asia through the Gulf of Ochotsk. It is much to be lamented,
that notwithstanding the frequent voyages made to and from
India, Australia, the Philippines, and the north-east coasts
of Asia, a vast accumulation of materials should remain
buried and unheeded in various ships' logs, which might
otherwise lead to general views, by which we might be en-
abled to connect Southern Asia with the more thoroughly
explored parts of Northern Asia and thus to solve questions
which were started as early as 1840. In order, there-
fore, not to blend together known facts with uncertain hypo-
theses, I will limit myself to the consideration of the Siberian
portion of the Asiatic continent, as far as it has been ex-
plored in a southerly direction to the parallel of 45° by Erman,
Hansteen, Due, Kupfler, Fuss, and myself. In no other part
of the earth has so extended a range of magnetic lines been
accessible to us in continental regions ; and the importance
which European and Asiatic Russia presents in this respect
was ingeniously conjectured even before the time of Leib-
nitz.95

95 I drew attention as early as 1843 to the fact, which I had ascer-
tained from documents presenved in the Archives of Moscow and,
Hanover (Asie Centrale, t. iii, pp. 469 — 476), that Leibnitz, who con-
structed the first plan of a French expedition to Egypt, was also the first
who endeavoured to profit by the relations which the Czar, Peter tho
Great, had established with Germany in 1712, by using his influence to
secure the prosecution of observations for " determining the position of
the lines of variation and inclination, and for insuring that these observa-
tions should be repeated at certain definite epochs" in different parts of
the Russian empire, whose superficies exceed those of the portions of
the moon visible to us. In a letter addressed to the Czar, discovered
by Pertz, Leibnitz describes a small hand-globe, or terrella, which is
still preserved at Hanover, and on which he had represented the curve
at which the variation is null (his linea magnetica primaria). Leibnitz
maintains that there is only one line of no variation, which divides the
terrestrial sphere into two almost equal parts, and hag four pwncta,
flexus contrarii, or sinuosities, where the curves are changed from con-
vex to concave. From the Cape dft Verd it passes in lat. 36° towards
the eastern shores of North America, after which it directs its course
through the South Pacific to Eastern Asia and New Holland. This line
is a closed one, and passing near both poles, it approaches closer to the
southern than the northern pole ; at the latter, the declination must
be 25° west, and at the former only 5°. The motion of this important
curve must have been directed towards the north pole at the beginning
of the 18th century. The variation must have ranged between 0° and
15° east over a great portion of the Atlantic Ocean, the whole of the

MAGNETIC VARIATION. 149

In order to follow the usual direction of Siberian expedi-
tions from west to east, and starting from Europe, we will
begin with the northern part of the Caspian Sea. Here, in
the small island of Birutschikassa, in Astracan, on Lake Elton,
in the Kirghis steppe, and at Uralsk, on the Jaik, between
45°43'and51°12'NMat., and 46° 37' and 51°24'E. long., the
variation fluctuates from 0° 10' east to 0° 37' west.96 Farther
northward, this line of no variation inclines somewhat more
towards the north-west, passing nftui* Nishnei-Nowgorod.97
In the year 1828 it passed between Osablikowo and Doskino
in the parallel of 56° K lat. an.d 43° E. long. It becomes
elongated in the direction of Russian Lapland between
Archangel and Kola, or more accurately according to Han-
steen (1830) between Umba and Ponoi.98 It is not until we
have passed over nearly two-tiirds of the greatest breadth
of Northern Asia, advancing eastward to the latitudes of
from 50° and 60° (a district in wLich at present the variation
is entirely easterly), that we reach the line of no variation,
which in the north-eastern part of the Lake of Baikal, rises
to a point west of Wiluisk, which riches the latitude of 68°,
in the meridian of Jakutsk 129° 50' E. long., forming at
this point the outer shell of the eastern group of oval con-
centric lines of variation, to which we have frequently re-
ferred, again sinking in the direction of Ochotsk in 143° 10'
E. long., intersecting the arc of the Kurile Islands, and
penetrating into the southern part of the Japanese Sea.
A 11 the curves of from 5° to 15° eastern variation which oc-
cupy the space between the lines of no variation in Western
and Eastern Asia, have their concavities turned northward.
The maximum of their curvature falls, according to Erman,
in 80° E. long., and almost in one meridian between Omsk

Pacific, Japan, a part' of China, and New Holland. " As the Czar's
private physician, Donelli, is dead, it would be advisable to supply hia
place by some one else, who will be disposed to administer very little
medicine, but who may be able to give sound scientific advice regarding
determinations of magnetic declination and inclination." ....
These hitherto unnoticed letters of Leibnitz certainly do not express
any special theoretical views.

96 See my Magnetic Observations, in Asie Centrale, t. iii, p. 460.

97 Erman, Astron. und Magnet. Beobachtuwgen (Reise urn, die Erde,
Abth. ii, Bd. 2, s. 532.

93 Hansteen, in Poggend. Ann. Bd. xxi, a. 371.

1 50 COSMOS.

and Tomsk, and are therefore not very different from the
meridian of the southern extremity of the peninsula of Hin-
dostan. The axis major of the closed oval group extends
28° of latitude as far as Corea.

A similar configuration, although on a still larger scale,
is exhibited in the Pacific. The closed curves here form an
oval between 20° N. lat. and 42° S. lat. The axis major
lies in 130° W. long. That which most especially distin-
guishes this singular group (the greater portion of which
belongs to the southern hemisphere and exclusively to the
sea) from the continent of Eastern Asia is. as has been
already observed, the relative succession in the value of the
curves of variation. In the former, the eastern variation
diminishes, whilst in the latter the western variation in-
creases the farther we penetrate into the interior of the oval.
The variation in the interior of this closed group in the
southern hemisphere amounts, however, as far as we know,
only to from 8° to 5°. Is it likely that there is a ring of
southern variation within the oval, or that we should again
meet with western variation farther to the interior of this
closed line of no variation ?

Curves of no variation, like all magnetic lines, have their
own history, which, however, does not as yet unfortunately
date further back than two centuries. Scattered notices
may indeed be met with, as early even as in the 14th and
15th centuries, and here again Hansteen has the great merit
of having collected and carefully compared together all the
various data. It would appear, that the northern magnetic
pole is moving from west to east, and the southern magnetic
pole from east to west ; accurate observations show us, how-
ever, that the different parts of the isogonic curves are pro-
gressing very irregularly, and that where they were parallel
they are losing their parallelism ; and lastly that the domain
of the declination of one denomination, that is to say, east
or west declination, is enlarging and contracting in very
different directions in contiguous parts of the earth. The
lines of no variation in Western Asia and in the Atlantic
are advancing from east to west ; the former line having
crossed Tobolsk in 1716, while in 1761, in Chappe's time, it
crossed J ekatherinenburg and subsequently Kasan, and in
1829 it was found to have passed between Osablikowo and

POLAR LIGHT. 151

Doskino, not far from Nishneinowgorod, and consequently
had advanced 24° 45' westward in the course of 113 years.
Is the line of the Azores, which Christopher Columbus deter-
mined on the 13th of September, 1492, the same, which,
according to the observations of Davis and Keeling, in 1607,
passed through the Cape of Good Hope r" and is it identical
with the one which we designate as the Western Atlantic.
and which passes from the mouth of the river Amazon to
the sea- coast of North Carolina ? if it be, we are led to ask
what has become of the line of no variation which passed in
1600 through Konigsberg, in 1620 (?) through Copenhagen,
from 1657 to 1662 through London, and which did not, ac-
cording to Picard, reach Paris, notwithstanding its more
eastern longitude, until 1666, passing through Lisbon some-
what before 1668 ? 10C Those points of the earth at which
no secular progression has been observed for long periods of
time are especially worthy of our notice. Sir John Herschel
has already drawn attention to a corresponding long period
of cessation in Jamaica,1 while Euler* and Barlow3 refer to a
similar condition in Southern Australia.

Polar Light.

We have now treated fully of the three elements of ter-
restrial magnetism in the three principal types of its mani-
festation, namely, Intensity, Inclination and Declination, in
reference to the movements which depend upon geographical
relations of place, and diurnal and annual periods. The ex-
traordinary disturbances which were first observed in the dip,
are as Halley conjectured, and as Dufay and Hibrter recog-
nised, in part forerunners, and in part accompaniments of the

99 Sabine, Magn. and Meteor. Observ. at the Cape of Good Hope, vol. i,
p. Ix.

00 In judging of the approximate epochs of the crossing of the line of
no variation, and in endeavouring to decide upon the claim of priority
in this respect, we must bear in mind how readily an error of 1° may
have been made with the instruments and methods then in use.

1 Cosmos, vol. i, p. 174.

2 Euler, in the Mem. de I'Acad. de Berlin, 1757, p. 176.

3 Barlow, in the Phil. Transact, for 1833, pt. ii, p. 671. Great un-
certainty prevails regarding the older magnetic observations of St.
Petersburg during the first half of the 18th century. The variation
seems to have been always 3° 15' or 3° 30' from 1726 to 1772 ! Hart-
eteen, Magnetismus der Erdc, s. 7, p. 143.

Io2 COSMOS.

magnetic polar light. I have already fully treated, in the
Picture of Nature, of the peculiarities of this luminous pro-
cess, which is often so remarkable for the brilliant display of
colours with which it is accompanied ; and more recent ob-
servations have in general accorded with the views which
I formerly expressed. " The Aurora borealis has not been
described merely as an external cause of a disturbance in the
equilibrium of the distribution of terrestrial magnetism, but
rather as an increased manifestation of telluric activity,
amounting even to a luminous phenomenon, exhibited on the
one hand, by the restless oscillation of the needle, and on the
other, by the polar luminosity of the heavens." The polar
light appears in accordance with this view to be a kind of
silent discharge or shock as the termination of a magnetic
storm, very much in the same manner as in the electric shock,
the disturbed equilibrium of the electricity is renewed
by a development of light by lightning, accompanied by
pealing thunder. The reiteration of a definite hypothesis in
the case of a complicated and mysterious phenomenon has at
all events the advantage of giving rise with a view to its
refutation to more persistent and careful observations of the
individual processes.4

Dwelling only on the purely objective description of these
processes, which are mainly based upon the materials yielded
by the beautiful and unique series of observations, which were
continued without intermission for eight months (1838, 1839),
— during the sojourn of the distinguished physicists, Lottin,
Bravais and Siljestrom — in the most northern parts of Scandi-
navia,8 we will first direct our attention to the sty- called black
segment of the Aurora, which rises gradually on the horizon
like a dark wall of clouds.6 The blackness is not, as Argel-

4 Cosmos, vol. i, pp. 187 — 199, and Dove,, in Poggend. Annalen, Bd.
xix, s. 388.

5 The able narrative of Lottin, Bravais, Lilliehob'k, and Siljestrom,
who observed the phenomena of the northern light from the 19th of
September, 1838,till the 8th of April, 1839, at Bossekop (69° 58' N. lat.)
in Finmark and at Jupvig (70° 6' N. lat.) was published in the fourth
section of Voyages en Scandinavie, en Laponie, au Spitzberg et aux Feroes,
sur la Corvette, la Recherche (Aurores boreales). To these observations
are appended important results obtained by the English superinten-
dent of the copper mines at Kalfiord (69° 56' N. lat.), pp. 401—435.

6 See the work above referred to (pp. 437—444) for a description of
the Segment obscure de V Aware boreale.

i'OLAR LIGHT.

ander observes, a mere result of contrast, since it is occasionally
visible before it is bounded by the brightly illuminated arch.
It must be a process effected within some part of the atmo-
sphere, for nothing has hitherto shown that the obscuration
is owing to any material blending. The smallest stars are
visible through the telescope in this black segment, as well
as in the coloured illuminated portions of the fully developed
Aurora, In northern latitudes, the black segment is seen far
less frequently than in more southern regions. It has even
been found entirely absent in these last named latitudes in
the months of February and March, when the Aurora was
frequent in bright clear weather ; and Keilhau did not once
observe it during the whole of a winter, which he spent at
Talwig in Lapland. Argelander has shown by accurate deter-
mination of the altitudes of stars, that no part of the polar
light exerts any influence on these altitudes. Beyond the
segment, there appear, although rarely, Hack rays, which Haii-
steen and I have often watched7 during their ascent ; blended
with these, appear round Hack patches, or spots, enclosed by
luminous spaces. The latter phenomena have been made a
special subject of investigation by Siljestrom.8 The central
portion of the corona of the Aurora (which owing to the
effect of linear perspective corresponds at its highest point
with the magnetic inclination of the place), is also usually
of a very deep black colour. Bravais regards this blackness
and the black rays as the effect of optical illusions of con-
trast. Several luminous arches are frequently simultaneously
present ; in some rare cases as many as seven or nine are seen

7 Schweigger's Jahrbuch der Chemie und Physik, 1826, Bd. xvi,
s. 198, and Bd. xviii, s. 364. The dark segment and the incontestible
rising of black rays or bands, in which the luminous process is annihi-
lated (by interference?) reminds us of Quet's Recherches sur V Electrochimie
dans Ic vide, and of Ruhmkorffs delicate experiments, in which in a
vacuum the positive metallic balls glowed with red light, while the nega-
tire balls showed a violet light, and the strongly luminous parallel strata
of rays were regularly separated from one another by perfectly dark
strata. " The light which is diffused between the terminal knobs of th«
two electric conductors divides into numerous parallel bands, which
are separated by alternate obscure and perfectly distinct strata."
C'omptes rendus de T Acad. des Sc. t. xxxv, 1852, p. 949.

8 Voyages en Scandinavie (Aurores bor.), p. 558. On the Corona and
bands of the northern light, see the admirable investigations of Bravaie,
pp. 502—514.

1 54 COSMOS.

advancing towards the zenith, parallel to one another ; while
in other cases they are altogether absent. The bundles of
rays and columns of light assume the most varied forms, ap-
pearing either in the shape of curves, wreathed festoons and
hooks, or resembling waving pennants or sails.9

In the higher latitudes, " the prevailing colour of the polar
light is usually white, while it presents a milky hue when the
Aurora is of faint intensity. When the colours brighten,
they assume a yellow tinge ; the middle of the broad ray be-
comes golden yellow, while both the edges are marked by
separate bands of red and green. When the radiation ex-
tends in narrow bands, the red is seen above the green.
When the Aurora moves sideways from left to right, or from
right to left, the red appears invariably in the direction to-
wards which the ray is advancing, and the green remains
behind it." It is only in very rare cases that either one of
the complementary colours, green or red, has been seen alone.
Blue is never seen, while dark red, such as is presented by
the reflection of a great fire, is so rarely observed in the
north that Siljestrom noticed it only on one occasion.10 The
luminous, intensity of the Aurora never even in Finmark
quite equals that of the full moon.

The probable connection which, according to my views,
exists between the polar light and the formation of very
small and delicate fleecy clouds (whose parallel and equivalent
rows follow the direction of the magnetic meridian), has met
with many advocates in recent times. It still remains a doubt-
ful question, however,11 whether, as the northern travellers,
Thienemann and Admiral Wrangel believe, these parallel
fleecy clouds are the substratum of the polar light, or whether

9 Op. cit. pp. 35, 37, 45, 67, 481 ("Draperie ondulante, flamme d"un
navire de guerre deployce horizontalement et agttee par le vent, crochets,
fragments d'arcs et de guirlandes)." M. Bevalet, the distinguished artist
to the expedition, has given an interesting collection of the many varied
forms assumed by this phenomenon.

10 See Voy. en Scandinavie (Aur. boreal.), pp. 523—528, 557.

11 Cosmos, vol i, p. 194 ; see also, Franklin, Narrative of a Journey to
the Shores of the Polar Sea in 1819—1822, p. 597; and Kiimtz, Lehr-
buch der Meteorologie, Bd. iii (1836), s. 488—490. The earliest conjec-
tures advanced in relation to the connection between the northern
light and the formation of clouds are probably those of Frobesius. (Sea
Auroras borealis spectacula, Helrnst, 1739, p. 139).

POLAT? LIGHT. .

they are not rather, as has been conjectured by Franklin,
Richardson, and myself, the effect of a meteorological process
generated by and accompanying the magnetic storm. The
regular coincidence in respect to direction between the very
fine cirrous clouds (polar bands) and the magnetic declination,
together with the turning of the points of convergence, were
made the subjects of my most careful observation on the
Mexican plateau in 1803, and in Northern Asia in 1829.
When the last named phenomenon is complete, the two ap-
parent points of convergence do not remain stationary, the
one in the north-east and the other in the south-west (in
the direction of the line which connects together the highest
points of the arch of the polar light which is luminous at
night), but move by degrees towards the east and west.12
A precisely similar turning, or translation of the line, which
in the true Aurora connects the highest points of the lumi-
nous arch, whilst its bases (the points of support by which it
rests on the horizon) change in the azimuth and move from
east-west towards north-south, has been several times ob-
served with much accuracy in Finmark.13 These clouds ar-

12 I will give a single example from my M.S. journal of my Siberian
journey: — "I spent the whole of the night of the 5 — 6th of August
(1829), separated from my travelling companions, in the open air, at
the Cossack outpost of Krasnajazarki, the most eastern station on the
Irtisch, on the boundary of the Chinese Dzungarei, and hence a place
whose astronomical determination was of considerable importance.
The night was extremely clear. In the eastern sky polar bands of
cirrous clouds were suddenly formed before midnight (which I have re-
corded as ' de petits moutons eyalement espaces, distribute en bandes
parall&les et polaires)' . Greatest altitude 35°. The northern point of con-
vergence is moving slowly toward the east. They disappear without reach-
ing the zenith ; and a few minutes afterwards, precisely similar cirrous
bands are formed in the north-east ; which move during a part of the
night, and almost till sunrise, regularly northward 70° E. An unusually
large number of falling stars and coloured rings round the moon
throughout the night. No trace of a true Aurora. Some rain falling
from speckled feathery masses of clouds. At noon on the 6th of
August the sky was clear, polar bands were again formed, passing from
N.N.E. to S.S.W., where they remained immoveabie, without altering
the azimuth, as I had so often seen in Quito and Mexico." (The mag-
netic variation in the Altai is easterly.)

13 Bravais, who, contrary to my own experience, almost invariably
observed that the masses of cirroup clouds at Bossekop were directed,
like the Aurora borealis, at right angles to the magnetic meridian
(Voyage* en Scandinavie, Phenomene de translation dans les pied* de

158 COSMOS.

ranged in the form of polar bands correspond, according to
the above developed views, in respect to position, with the
luminous columns or bundles of rays which ascend in the
true Aurora towards the zenith from the arch, which is
generally inclined in an east and west direction ; and they
cannot, therefore, be confounded with those arches of which
one was distinctly seen by Parry in bright day-light after
the occurrence of a northern light. This phenomenon oc-
curred in England on the 3rd of September, 1827, when
columns of light were seen shooting up from the luminous
arch even by day.14

It has frequently been asserted that a continuous evolu-
tion of light prevails in the sky immediately around the
northern magnetic pole. Bravais, who continued to prose-
cute his observations uninterruptedly for 200 nights, during
which he accurately described 152 Aurorse, certainly asserts
that nights, in which no northern lights are seen, are alto-
gether exceptional, but he has sometimes found even when the
atmosphere was perfectly clear, and the view of the horizon
was wholly uninterrupted, that not a trace of polar light
could be observed throughout the whole night, or else that
the magnetic storm did not begin to be apparent until a very
late hour. The greatest absolute number of northern lights
appears to occur towards the close of the month of September ;
and as March, when compared with February and April,
seems to exhibit a relatively frequent occurrence of the phe-
nomenon, we are here led, as in the case of other magnetic
phenomena, to conjecture some connection with the period

I'arc des Aurores bore"ales, pp. 534 — 537), describes with his accustomed
exactitude the turnings or rotations of the true arch of the Aurora
borealis, pp. 27, 92, 122, 487. Sir James Ross has likewise observed in
the southern hemisphere similar progressive alterations of the arch of
the Aurora (a progression in the southern lights from W.N.W. — E.S.E.
to N.N.E. — S.S.W.) Voyage in the Southern and Antarctic Regions, vol. i,
p. 311. An absence of all colour seems to be a frequent characteristic
of southern lights, vol. i, p. 266, vol. ii, p. 209. Regarding the absence
of the northern light in some nights in Lapland, see Bravais, Op. cit.
p. 545.

14 Cosmos, vol. i, p. 191. The arch of the Aurora seen in bright day-
light reminds us by the intensity of its light of the miclei and tails of
the comets of 1843 and 1847, which were recognised in the immediate
vicinity of the sun in North America, Parma, and London. Op. cit.
vol. i, p. 85, vol. iii. p. 543.

POLAR LIGHT. L57

of the equinoxes. To the northern lights which have been
seen in Peru, and to the southern lights which have been
visible in Scotland, we may add a coloured Aurora, which
was observed for more than two hours continuously by
Lafond in the Candide, on the 14th of January, 1831, south
of New Holland, in latitude 45°.16

The accompaniment of sound in the Aurora has been as
definitely denied by the French physicists and Siljestrom at
Bossekop16 as by Thienemann, Parry, Franklin, Richardson,
Wrangel, and A.njou. Bravais estimated the altitude of the
phenomenon to be fully 51307 toises (or 52 geographical
miles), whilst an otherwise very careful observer, Farquhar-
son, considers that it scarcely amounts to 4000 feet. The
data on which all these determinations are based are very
uncertain, and are rendered less trustworthy by optical illu-
sions, as well as by erroneous conjectures regarding the posi-
tive identity of the luminous arch seen simultaneously at two
remote points. There is, however, no doubt whatever of tli€
influence of the northern light on declination, inclination,
horizontal and total intensity, and consequently on all the
elements of terrestrial magnetism, although this influence
is exerted very unequally in the different phases of this great
phenomenon, and on the different elements of the force.
The most complete investigations of the subject were those
made in Lapland by the able physicists Siljestrom and
Bravais17 (in 1838 — 1839), and the Canadian observations at
Toronto (1840 — 1841), which have been most ably dis-
cussed by Sabine.18 In the preconcerted simultaneous ob-
servations which were made by us at Berlin (in the Men-
delssohn-Bartholdy Garden), at Freiberg below the surface
of the earth, at St. Petersburgh, Kasan and Nikolajew, we
found that the magnetic variation was affected at all these
places by the Aurora boreal is, which was visible at Alford in
Aberdeenshire (57° 15' N. lat.) on the night of the 19-20th
of December, 1829. At some of these stations, at which

15 Comptes rendus de PAcad. des Sciences, t. iv, 1837, p. 589.
6 Voyages en Scandinavie, en Laponie, etc., (Awores boreales,) p. 559 ;
and Martin's Trad, de la Meteorologie de Kaemtz, p. 460. In reference
to the conjectured elevation of the northern light, see Bravais, Op. cit.
pp. 549, 559.

V Op. cit. p. 462.

18 Sabine, Unusual Mcynet. Disturbances, pt. i, pp. xviii, xxii, 3, 54.

16'S COSMOS.

the other elements of terrestrial magnetism could be noted,
the magnetic intensity and inclination were affected no less
than the variation.19

D-uring the beautiful Aurora, which Professor Forbes ob-
served at Edinburgh on the 21st of March, 1833, the inclina-
tion was strikingly small in the mines at Freiberg, while the
variation was so much disturbed that the angles could scarcely
be read off. The decrease in the total intensity of the mag-
netic force which has been observed to coincide with the in-
creasing energy of the luminosity of the northern light is a
phenomenon which is worthy of special attention. The mea-
surements which I made in conjunction with Oltmanns at
Berlin during a brilliant Aurora on the 20th of December,
1806, M and which are printed in Hansteen's " Unter-
suchungen iiber den Magnetismus der Erde," were con-

19 Dove, in Poggend. Ann. Bd. xx, s. 333 — 341. The unequal influ-
ence which an Aurora exerts on the dipping needle at points of the
earth's surface, which lie in very different meridians, may in many
cases lead to the local determination of the active cause, since the mani-
festation of the luminous magnetic storm does not by any means always
originate in the magnetic pole itself ; while, moreover, as A rgelander
maintained and as Bravais has confirmed, the summit of the luminous
arch is in some cases as much as 11° from the magnetic meridian.

20 "On the 20th of December, 1806, the heavens were of an azure
blue, with not a trace of clouds. Towards 10 P.M. a reddish-yellow
luminous arch appeared in the N.N.W., through which I could distin-
guish stars of the 7th magnitude in the night telescope. I found the
azimuth of this point by means of a Lyrse, which was almost directly
under the highest point of the arch. It was somewhat further west
than the vertical plane of the magnetic variation. The Aurora, which
was directed N.N.W., caused the north pole of the needle to be deflected,
for, instead of progressing westward like the azimuth of the arch, the
needle moved back towards the east. The changes in the magnetic
declination, which generally amount to from 2' 27" to 3' in the
nights of this month, increased progressively and without any great
oscillation to 26' 28" during the northern light. The variation was the
smallest about 9h. 12m. when the Aurora was the most intense. We
found that the horizontal force amounted to 1' 37".73 for 21 vibrations
during the continuance of the Aurora, while at 9h. 50m: A.M., and con-
sequently long after the disappearance of the Aurora, which had en-
tirely vanished by 2h. 10m. A.M. it was 1' 37".17 for the same number
of vibrations. The temperature of the room, in which the vibrations of
the small needle were measured, was in the first case 37°.76 F. and
in the second 37°.04 F. The intensity was therefore slightly diminished
during the continuance of the northern light. The moon presented no
coloured rings." From my magnetic journal, see Hansteen, s. 4d&.

TERRESTRIAL MAGNETISM. 159

firmed by Sabine and the French physicists in Lapland m
1838.21

While in this careful development of the present condition
of our positive knowledge of the phenomena of terrestrial
magnetism, I have necessarily limited myself to a mere ob-
jective representation of that which did not even admit of
being elucidated by merely theoretical views, based only
upon induction and analogy ; I have likewise purposely ab-
stained in the present work from entering into any of those
^eognostic hypotheses, in which the direction of extensive
mountain chains and of stratified mountain masses is con-
sidered in relation to its dependence upon the direction of
magnetic lines, more especially the isoclinal and isodynamic
systems. I am far from denying the influence of all cosmical
primary forces — dynamic and chemical forces — as well as of
magnetic and electrical currents on the formation of crystal-
line rocks and the filling up of veins ;22 but owing to the
progressive movement of all magnetic lines and their conse-
quent change of form, their present position can teach us
nothing in reference to the direction in primeval ages of
mountain chains, which have been upheaved at very different
epochs, or to the consolidation of the earth's crust, from
which heat was being radiated during the process of its
hardening.

Of a different order, not referring generally to terrestrial
magnetism, but merely to very partial local relations, are
those geognostic phenomena, which have been designated by
the name of the magnetism23 of mountain masses. These
phenomena engaged much of my attention before my Ame-
rican expedition, at a time when I was occupied in examin-
ing the magnetic serpentine rock of the Haidberg moun-
tain in Franconia in 1796, and then gave occasion in

21 Sabine, On Days of Unusual Magn. Disturbances, pt. i, p. xviii.
" M. Bravais concludes from the observations made in Lapland that the
horizontal intensity diminishes when the phenomenon of the Aurora
borealis is at its maximum" (Martins, p. 461 ).

** Delesse, Stir 1'association des mineraux dans les roches qui ont
un pouvoir magnetique eleve, in the Comptes rendus de I'Acad. dcs Sc.
t. xxxi, 1850, p. 806; and Annales des Mines, 4eme Sfirie, t. xv (1349),
p. 130.

-"' Reich, Ueber Gebirys-und Gcsteins-Magnetismus, in Poggend. A itn.
Bd. Ixvii, s. iJj.

160 COSMOS.

Germany to a considerable amount of literary dissension,
which, however, was of a very harmless nature. They pre-
sent a number of problems, which are by no means incapable
of solution, but which have been much neglected in recent
times, and only very imperfectly investigated both as regards
observation and experiment. The force of this magnetism
of rocks may be tested for the determination of the increase
of magnetic intensity by means of pendulum experiments
and by the deflection of the needle in broken off fragments of
hornblende and chloritic schists, serpentine, syenite, dolerite,
basalt, melaphyre and trachyte. We may in this manner
decide by a comparison of the specific gravity, by the rinsing
of finely pulverised masses, and by the application of the
microscope, whether the intensity of the polarity may not
depend in various ways upon the relative position, rather
than upon the quantity, of the granules of magnetic iron
and protoxide of iron, intermixed in the mass. More im-
portant, however, in a cosmical point of view is the question
which I long since suggested in reference to the Haidberg
mountain ; whether there exist entire mountain ranges, in
which opposite polarities are found to occur on opposite de-
clivities of the mass.24 An accurate astronomical determi-

24 This question was made the subject of lively discussion when, in
the year 1796, at the time that I fulfilled the duties of superintendent
of the mining operations in the Fichtelgebirge, in Franconia, I dis-
covered the remarkable magnetic serpentine mountain (the Haidberg)
near Gefress, which had the property at some points of causing the
needle to be deflected at a distance of even 23 feet (Intelligenz-Blatt der
Allgem. Jenaer Litteratur-Zeitung, Dec. 1796, No. 169, s. 1447, and
Mdrz, 1797, No. 38, s. 323 — 326; Gren's Neues Journal der Physik,
Ed. iv, 1797, s. 136 ; Annales de Chimie, t. xxii, p. 47). I had thought
that the magnetic axes of the mountain were diametrically opposed to
the terrestrial poles ; but according to the investigations of Bischoff
and Goldfuss, in 1816 (Beschreibung des Fichtelgelirges, Bd. i, s. 176), it
would appear that they discovered magnetic poles, which penetrated
through the Haidberg and presented opposite poles on the opposite
declivities of the mountain, while the directions of the axes were not
the same as I had given them. The Haidberg consists of dull green
serpentine, which partially merges into chloritic and hornblende schists.
At the village of Voysaco, in the chain of the Andes of Pasto, we Baw
the needle deflected by fragments of porphyritic clay, while on the
ascent to (Jhimboi-azo, groups of columnar masses of trachyte disturbed
thp motion of the needle at a distance of three feet. It struck me a-i n
very remarkable fact that I should have found in the black and red

MAGNETISM. 161

nation of the position of such magnetic axes of a mountain
would be of the greatest interest, if it could be ascertained

obsidians of Quinche, north of Quito, as well as in the gray obsidian of
the Cerro de la Navajas of Mexico, large fragments with distinct poles.
The large collective magnetic mountains in the Ural chain, as Blagodat,
near Kuschwa, Wyssokaja Gora, at Nishne Tagilsk, and Katschkanar,
near Nishne Turinsk, have all broken forth from augitic or rather
uralitic porphyry. In the great magnetic mountain of Blagodat, which
I investigated with Gustav Rose, in our Siberian expedition, in 1829,
the combined effect of the polarity of the individual parts did not indeed
appear to have produced any determined and recognisable magnetic axes.
In close' vicinity to one another lie irregularly mixed opposite poles. A
similar observation had previously been made by Ennan (Reise urn die
Erde, Bd. i, a. 362). On the degree of intensity of the polar force in
serpentine, basaltic, and trachytic rock, compared with the quantity of
magnetic iron and protoxide of iron, intermixed with these rocks, as well
as on the influence of the contact of the air in developing polarity, which
had already been maintained by Gmelin and Gibbs, see the numerous and
very admirable experiments of Zaddach, in his Beobachtungen uber die
Magnetische Polaritdt des Basaltes und der Trachytischen Gestdne, 1851,
s. 56, 65 — 78, 95. A comparison of many basaltic quarries, made with a
view of ascertaining the polarity of individual columns which have stood
isolated for a long period, and an examination of the sides of these
columns which have been recently brdught in contact with the outer air
in consequence of the removal from individual masses of a certain
depth of earth, have led Dr. Zaddach to hazard the conjecture (see s.
74, 80) that the polar property, which always appears to be manifested
with the greatest intensity in rocks to which the air has been freely ad-
mitted, and which are intersected by open fissures, " diffuses itself from
without inwards, and generally from above downwards." Gmelin ex-
presses himself as follows in respect to the great magnetic mountain,
Ulu-utasse-Tau, in the country of the Baschkiri, near the Jaik : — " The
sides which are exposed to the open air exhibit the most intense mag-
netic force, while those which lie under ground are much weaker"
(Reise durch Siberien, 1740—1743, Bd. iv, s. 345). My distinguished
teacher, Werner, in describing the magnetic iron of Sweden, in hia
lectures, also spoke of " the influence which contact with the atmo-
sphere might have, although not by means of an increased oxidation, in
rendering the polar and attracting force more intense." It is asserted
by Colonel Gibbs, in reference to the magnetic iron mines at Succas-
suny, in New Jersey, that "the ore raised from the bottom of the mine
has no magnetism at first, but acquires it after it has been some time
exposed to the influence of the atmosphere" (On the connexion of Mag-
netism and Light, in Silliman's American Journal of Science, vol. i, 1819,
p. 89). Such an assertion as this ought assuredly to stimulate obser-
vers to make careful and exact investigations ! When I drew attention
in the text (see page 160), to the fact that it was not only the quantity
of the small particles of iron which we're intermixed in the stone, but
Mso their relative distribution (their position) which ac^ed as the 19-
VOL. V. M

162 COSMOS.

after considerable periods of time, that the three variable
elements of the total force of terrestrial magnetism caused
either an alteration in the direction of the axes, or that such
small systems of magnetic forces were at least apparently
independent of these influences.

II.

Reaction of the interior of the Earth upon its surface ; mani-
festing itself : — a. Merely dynamically, by tremulous un-
dulations (earthquakes] ; — b. By the high temperature of
mineral springs, and by the difference of the intermixed
salts and gases (Thermal springs); c. By the outbreak of
elastic fluids, sometimes accompanied by phenomena of
spontaneous ignition (ffas and mud volcanoes, burning
naphtha springs, Salses) ; d. By the grand and mighty
actions of true volcanoes, which (when they have a perma-
nent connexion with the atmosphere by fissures and craters)
throw up fused earth from the depths of the interior, partly
only in the form of red-hot cinders, but partly submitted to
varying processes of crystalline rock formation, poured out
in long, narrow streams.

In order to maintain, in accordance with the fundamental
plan of this work, the co-ordination of telluric phenomena

sultant upon the intensity of the polar force, I considered the small
particles to be so many small magnets. Seethe new vieAvs regarding this
subject in a treatise by Melloui, read by that distinguished physicist
before the Royal Academy at Naples, in the month of January, 1853
(Esperienze intorno al Magnetisms delle Rocche, Mem. i, Sulla Polarita).
The popular notion which has been so long current, more especially on
the shores of the Mediterranean, that if a magnetic rod be rubbed with
an onion, or brought in contact with the emanations of the plant, the
directive force will be diminished, while a compass thus treated would
mislead the steersman, is mentioned in Prodi Diadoclii Paraphrases
Ptolem. libriiv. deSideruma/ectionibus, 1635, p. 20 (Delambre, Hist.de
I' Astronomic Ancitnne, t. ii, p. 545). It is difficult to conceive what
could have given occasion to so singular a popular error.

VULCANIC ITY. 163

— the co-operation of a single system of impelling forces —
in the descriptive representation, we must here remind the
reader, how, starting from the general pr -perties of matter,
and the three principal directions of its activity (attraction,
vibrations producing light and heat, and electro-magnetic pro-
cesses], we have in the first section taken into consideration
the size, form, and density of our planet, its internal dif-
fusion of heat and of magnetism, in their effects of intensity,
dip, and variation, changing in accordance with definite
laws. The directions of the activity of matter just mentioned
are nearly allied * manifestations of one and the same primi-
tive force. They occur in a condition of the greatest inde-
pendence of all differences of matter, in gravitation and
molecular attraction. We have at the same time represented
our planet in its cosmical relation to the central body oi its
system ; because the internal primitive heat, which is pro-
bably produced by the condensation of a rotating nebular
ring, is modified by the action of the sun (Insolation). With
the same view, the periodical action of the solar spots (that
is to say, the frequency or rarity of the apertures in the
solar envelopes) upon terrestrial magnetism, has been referred
to, in accordance with the most recent hypotheses.

The second section of this volume is devoted to the
entirety of those telluric phenomena which are to be
ascribed to the constantly active reaction of the interior oj
the earth upon its surface? To this entirety I give the
general name of Vulcanism or Vulcanicity ; and I regard it
as advantageous to avoid the separation of that which is
causally connected and differs only in the strength of the
manifestation of force and the complication of physical pro-
cesses. By taking this general view, small and apparently
unimportant phenomena acquire a greater significance.
The unscientific observer who comes for the first time
upon the basin of a thermal spring and sees gases cap-
able of extinguishing light rising in it, or who wanders
amongst rows of changeable cones of mud volcanoes, scarcely
exceeding himself in height, never dreams that in the calm
space occupied by the latter, eruptions of fire to the he'ght
of many thousand feet have often taken place ; and that one

1 Cosmos, vol. iii, p. 39.

2 Cotmos, vol. i, p. 197 — 199,

164 COSMOS.

and the same internal force produces colossal craters of eleva-
tion, nay even the mighty, desolating, lava-pouring volcanoes
of Etna and the Peak of Teyde, and the cinder-erupting
Cotopaxi and Tunguragua.

Amongst the multifarious, mutually intensifying, phenomena
of the reaction of the interior of the earth upon its external
crust, I first of all separate those, the essential character of
which is purely dynamical, namely, that of movement or tre-
mulous undulations in the solid strata of the earth ; a volcanic
activity which is not necessarily accompanied by any chemical
changes of matter, or by the expulsion or production of any-
thing of a material nature. In the other phenomena of the
reaction of the interior upon the exterior of the earth : — in
gas and mud volcanoes, burning springs and salses, and in
the large burning mountains to which the name of volcano
was first, and for a long time exclusively, applied, the
production of something of a material nature (gaseous or
solid), and processes of decomposition and gas-evolution,
such as the formation of rocks from particles arranged in a
crystalline form, are never wanting. When most fully gene-
ralized, these are the distinctive characters of the volcanic
vital activity of our planet. In so far as this activity is to
be ascribed in great measure to the high temperature of the
innermost strata of the earth, it becomes probable that all
cosmical bodies which have become conglomerated with an
enormous evolution of heat, and passed from a state of vapour
to a solid condition, must present analogous phenomena. The
little that we know of the form of the moon's surface, ap-
pears to indicate this.3 — Upheaval and plastic activity in
the production of crystalline rock from a fused mass, are
conceivable even in a sphere which is regarded as destitute
of both air and water.

The genetic connexion of the classes of volcanic pheno-
mena here referred to is indicated by the numerous traces
of the simultaneousness of the simpler and weaker with
stronger and more complex effects, and the accompanying
transitions of the one into the other. The arrangement of
the materials in the representation selected by me is justified
by such a consideration. The increased magnetic activity
of our planet, the seat of which, however, is not to be sought
3 Cosmos, vol. iii, p. 44; iv, pp. 426, 491, 495—498.

EARTHQUAKES. 165

in the fused mass of the interior (even though, according to
Lenz and Kiess, iron, in the fused state, may be capable of
conducting an electrical or galvanic current), produces evolu-
tion of light in the magnetic poles of the earth, or at least
usually in their vicinity. We concluded the first section of
the volume on telluric phenomena with the luminosity of the
earth. This phenomenon of a luminous vibration of the ether
by magnetic forces is immediately followed by that class of
volcanic agencies, which, in their essential nature, act purely
dynamically, exactly like the magnetic force : — causing move-
ment and vibrations in the solid ground, but neither produc-
ing nor changing anything of a material nature. Secondary
and unessential phenomena (the ascent of flames during the
earthquake, and eruptions of water and evolutions of gas*
following it) remind one of the action of thermal springs and
salses. Eruptions of flame, visible at a distance of many
miles, and masses of rock, torn from their deep seats and
hurled about,6 are presented by the salses, which thus, as it
were, prepare us for the magnificent phenomena of the true
volcanoes; which again, between their distant epochs of erup-
tion, like the salses, only exhale aqueous vapour and gases
from their fissures. So remarkable and instructive are the
analogies which are presented in various stages by the grada-
tions of vulcanism.

a. Earthquakes.

(Amplification of the Picture of .Nature.
Cosmos, vol. i. pp. 199—213).

Since the appearance in the first volume of this work
(1845) of the general representation of the phenomena of
earthquakes, the obscurity, in which the seat and causes of
these phenomena are involved, has but little diminished ;
but the excellent works6 of Mallet (1846) and Hopkins
(1847) have thrown some light upon the nature of concussions,
the connection of apparently distinct effects and the separa-

4 Cosmos, vol. i, p. 214.

6 Cosmos, vol. i, p. 222. Compare Bertrand-Geslin, " Sur les roches
lancges par le Volcan de bouedu Monte Zibio pres du bourg de Sassuolo,"
in Humboldt, Voyage aux Regions Equinoxiales du Nouveau Continent
(Relation ffistorique), t. iii, p. 566.

'Robert Mallet, in the Transactions of the Royal Irish Academy ,
vol. xxi (1848), pp. 51—113, and First Report on the Facts of Earth-
quake Phenomena, in the Report of the Meeting of the British A ssociatior^

166 COSMOS.

tion of chemical and physical processes, which may accom-
pany it or occur simultaneously with it. Here, as elsewhere,
a mathematical mode of treatment, such as that adopted by
Poisson, may have a beneficial effect. The analogies between
the oscillations of solid bodies and the sound-waves in the
ordinary atmosphere to which Thomas Young7 had already
called attention, are peculiarly adapted to lead to simpler
and more satisfactory views, in theoretical considerations
upon the dynamics of earthquakes.

Displacement, commotion, elevation, and formation of fissures
indicate the essential character of the phenomenon. We
have to distinguish the efficient force, which, as the impulse,
gives rise to the vibration ; and the nature, propagation, in-
crease or diminution of the commotion. In tiie Picture of
Nature I have described what is especially manifested to the
senses ; what I had myself the opportunity of observing for
so many years on the sea, on the sea-bottom of the plains
(Llanos), and at elevations of eight to fifteen thousand feet ;
on the margin of the craters of active volcanos, and in re-
gions of granite and mica schist, twelve hundred geographical
miles from any eruptions of fire \ in districts where at cer-
tain periods the inhabitants take no more notice of the num-
ber of earthquakes, than we in Europe of that of the showers
of rain, and where Bonpland and I were compelled to dis-
mount, from the restiveness of our mules, because the earth
shook in a forest for 15 to 18 minutes without intermission.
By such long custom, as Boussingault subsequently expe-
rienced even in a still higher degree, one becomes fitted for
quiet and careful observation, and also for collecting varying
evidence with critical care on the spot, nay, even for ex-
amining under what conditions the mighty changes of the
surface of the earth, the fresh traces of which one recognises,
have taken place. Although five years had already elapsed

] 850, pp. 1 — 89 ; also Manual of Scientific Inquiry for the Use of the
British Navy, 1849, pp. 196 — 223. William Hopkins, On the Geological
Theories of Elevation and Earthquakes, in the Report of the British Asso~
ciation for 1847, pp. 33 — 92. The rigorous criticism to which Mr.
Mallet has subjected my previous work in his very valuable memoirs
(Irish Transactions, pp. 99 — 101, and Meeting of the British Association
at Edinburgh, p. 209), has been repeatedly made use of by me.
7 Thomas Young, Lectures on Natural Philosophy, 1807, vol. f,
717.

EARTHQUAKES. 167

since the terrible earthquake of Riobamba, which, on the
4th ot February, 1797, destroyed upwards of 30,000 people in
a few minutes,8 we nevertheless saw the formerly advancing
cone of the Moya9 which rose out of the earth, and witnessed
the employment of this combustible substance for cooking in
che huts of the Indians. I might describe the results of alte-
rations of the ground from this catastrophe, which, although
on a larger scale, were exactly analogous to those presented
by the famous earthquake of Calabria (February 1783),
and were long considered to have been represented ia an
incorrect and exaggerated manner, because they could not
be explained in accordance with hastily formed theories.

By carefully separating, as we have already indicated, the
investigation of that which gives the impulse to the vibra-
tion, from that of the nature and propagation of the waves
of commotion, we distinguish two classes of problems of very
unequal accessibility. The former, in the present state of
our knowledge, can lead to no generally satisfactory results,
as is the case with so many problems in which we wish to
ascend to primary causes. Nevertheless, whilst we are en-
deavouring to discover laws in that which is submitted to
actual observation, it is of great cosmical interest that we
should bear constantly in mind the various genetic explana-
tions which have hitherto been put forward as probable.
As with all vulcanicity, the greater part of these refer,
under various modifications, to the high temperature and
chemical nature of the fused interior of the earth ; one of the
most recent explanations of earthquakes in trachytic regions,
is the result of geognostic suppositions regarding the want of
cohesion in rocky masses raised by volcanic action. The fol-
lowing summary furnishes a more exact but very brief indi-
cation of the variety of views as to the nature of the first
je to the commotion : —

The nucleus of the earth is supposed to be in a state of
igneous fluidity, as the consequence of every planetary
process of formation from a gaseous material, by evolution

8 I follow the statistical account communicated to me by the Corre-
gidoi- of Tacunga in 1802. It rose to a loss of 30,000—34,000 people,
but some twenty years later the number of those killed immediately
was reduced by about one-third.

9 CVwnuw, voL i, p. 209, Bohn's edition.

168 COSMOS.

of heat during the transition from fluidity to solidity.
The external strata were first cooled by radiation, and
were the first to become consolidated. The commotion is
occasioned by an unequal ascent of elastic vapours formed
(at the limit between the fluid and solid parts) either from
the fused terrestrial mass alone, or from the penetration
of sea-water into higher strata of rock, nearer to the sur-
face of the earth, the sudden opening of fissures, and by
the sudden ascent of vapours produced in the hotter and
consequently more elastic depths. The attraction of the
moon and sun10 on the fluid, fused surface of the nucleus

10 Hopkins has expressed doubts as to the action upon the fused
" subjacent fluid confined into internal lakes," at the Meeting of the
British Association for 1847 (p. 57), as Mallet has also done with regard
to "the subterraneous lava tidal wave, moving the solid crust above it,"
at the British Association Meeting for 1850 (p. 20). Poisson also, with
whom I have often spoken regarding the hypothesis of the subterranean
ebb and flow, caused by the sun and moon, considers the impulse,
which he does not deny, to be inconsiderable, " as in the open sea the
effect scarcely amounts to 14 inches." Ampere, on the other hand,
says : — " Those who admit the fluidity of the internal nucleus of the
earth, do not appear to have sufficiently considered the action which
would be exercised by the moon upon this enormous liquid mass ; an
action from which would result tides analogous to those of our seas,
but far more terrible, both from their extent and from the density of
the liquid. It is difficult to .conceive how the envelope of the earth
should be able to resist the incessant action of a sort of hydraulic
ram(?) of 1400 leagues in length" (Ampere, Theorie de la Terre, in Revue
des deux Mondes, July, 1833, p. 148). If the interior of the earth be
fluid, which in general cannot be doubted, as, notwithstanding the
enormous pressure, the particles are still displaceable, then the same
conditions are fulfilled in the interior of the earth that give rise on the
surface to the ocean tides; and the tide-producing force will con-
stantly become weaker in approaching the centre, as the difference of
the distances of every two opposite points, considered in their relation
to the attracting bodies, constantly becomes less in receding from the
surface, and the force depends exclusively upon the difference of the
distances. If the solid crust of the earth opposes a resistance to this
effort, the interior of the earth will only exert a pressure against its
crust at these points ; as my astronomical friend, Dr. Brunnow, ex-
presses himself, no more tide will be produced than if the ocean had an
indestructible covering of ice. The thickness of the solid unf used crust
of the earth Is calculated from the fusing points of the different kinds
of rock, and the law of the increase of heat from the surface into the
depths of the earth. I have already (Cosmos, vol. i, p. 26), justified
the assumption that, at somewhat more than twenty geographical

EARTHQUAKES. 1 69

of the earth, may also be regarded as the subsidiary action
of a non -telluric cause, by which an increased pressure must
be produced, either immediately against a solid, superim-
posed rocky arch ; or indirectly, when the solid mass is
separator!, in subterranean basins, from the fused, fluid
mass by elastic vapours.

The nucleus of our planet is supposed to consist of un-
oxidised masses, the metalloids of the alkalies and earths.
Volcanic activity is excited in the nucleus by the access
of water and air. Volcanoes certainly pour forth a great
quantity of aqueous vapour into the atmosphere ; but the
assumption of the penetration of water into the volcanic
focus is attended with much difficulty, considering the
opposing pressure11 of the external column of water and

miles (21T6Q, 25 English) below the surface, a heat capable of melting
granite prevails. Nearly the same number (45,000 metres=24 geo-
graphical miles) was named by Elie de Beaumont (Geologic, edited by
Vogt, 1846, vol. i, p. 32), as the thickness of the solid crust of the
earth. Moreover, according to the ingenious experiments of Bischot
on the fusion of various minerals, of which the importance to the pro-
gress of geology is so great, the thickness of the unfused strata of the
earth is between 122,590 and 136,448 feet, or on the average 21-i geo-
graphical (24 g English) miles; see Bischof, Warmelehre des Innern unsers
Erdkorpers, pp. 286 and 271. This renders it the more remarkable to
me to find that, with the assumption of a definite limit between the
solid and fused parts, and not of a gradual transition, Hopkins, from
the fundamental principles of his speculative geology, establishes the
result that " the thickness of the solid shell cannot be less than about
one-fourth or one-fifth(?) of the radius of its external surface" (Meeting
of British Association, 1847 ', p. 51). Cordier's earliest supposition was
only 56 geographical (72 English) miles, without correction, which is
dependent upon the increased pressure of the strata at great depths,
and the hypsqmetrical form of the surface. The thickness of the solid
part of the crust of the earth is probably very unequal.

11 Gay Lussac, Reflexions sur les Volcans, in the Annales de Chimie et
de Physique, tome xxii, 1823, pp. 418 and 426. The author, who, in
company with Leopold von Buch and myself, observed the great erup-
tion of lava from Vesuvius in September, 1805, has the merit of having
submitted the chemical hypotheses to a strict criticism. He seeks for
the cause of volcanic phenomena in a "very energetic and still unsatis-
fied affinity between the substances, which a fortuitous contact permits
them to obey ;" in general he favours the hypothesis of Davy and
Ampere, which is now given up, " supposing that the radicals of silica,
alumina, lime, and iron are combined with chlorine in the interior of
the earth ," and the penetration of sea water does not appear to him to
be improbable unde^ certain conditions (pp. 419, 420, 423, and 42t>),

170 COSMOS.

of the internal lava ; and the deficiency, or, at all events,
very rare occurrence of burning hydrogen gas during the
eruption, (which the formation of hydrochloric acid,la
ammonia, and sulphuretted hydrogen, certainly does not
sufficiently replace) has led the celebrated originator of
this hypothesis to abandon it of his own accord.13

According to a third view, that of the highly endowed
South American traveller, Boussingault, a deficiency of
coherence in the trachytic and dolentic masses which form
the elevated volcanoes of the chain of the Andes, is re-
garded as a primary cause of many earthquakes of very
great extent. The colossal cones and dome-like summits
of the Cordilleras, according to this view, have by no
means been elevated in a soft and semifluid state, but
have been thrown up and piled on one another when
fectly hardened, in the form of enormous, shai
fragments. In an elevation and piling of this description,
large interstices and cavities have necessarily been pro-
duced ; so that by sudden sinking, and by the fall of solid
masses which are too weakly supported, shocks are pro-
duced.14

Upon the difficulty of a theory founded upon the penetration of water,
Bee Hopkins, Brit. Assoc. Rep. 1847, p. 38.

12 According to the beautiful analyses made by Boussingault, on the
margins of five craters (Tolima, Purace, Pasto, Tuqueras, and Cumbal),
hydrochloric acid is entirely wanting in the vapours poured forth by
the South American volcanoes, but not in those of Italy (Annales de
Chimie, tome lii, 1833, pp. 7 and 23).

13 Cosmos, vol. i, p. 234, Boon's edition. Whilst Davy, in the most
distinct manner, gave up the opinion that volcanic eruptions are a con-
sequence of the contact of the metalloid bases with water and air, he
still asserted that the presence of oxidizable metalloids in the interior
of the earth might be a co-operating cause in volcanic processes already
commenced.

14 Boussingault says : — " I attribute most of the earthquakes in the
Cordillera of the Andes to falls produced in the intei-ior of these moun-
tains by the subsidence which takes place, arid which is a consequence of
their elevation. The mass which constitutes these gigantic ridges has
not been raised in a soft state ; the elevation did not take place until
after the solidification of the rocks. I assume, therefore, that the ele-
vated masses ot the Andes are composed of fragments heaped upon each
other. The consolidation of the fragments could not be so stable from
the beginning as that there should be no settlements after the elevation,
or that there should be no interior movements in the fragmentary
masses" (Boussingault, /Siw les TremUcmcm de Terre des Andes, in

EARTHQUAKES. 171

The effects oftJie impulse, the waves of commotion, may be
reduced to simple mechanical theories with more distinctness
than is furnished by the consideration of the nature of the
first impulse, which indeed may be regarded as heterogeneous.
As already observed, this part of our knowledge has advanced
essentially in very recent times. The earth-waves have been
represented in their progress and their propagation through
rocks of different density and elasticity ;15 the causes of the
rapidity of propagation, and its diminution by the refrac-
tion, reflection, and interference™ of the oscillations have been

Annales de Chimie et de Physique, tome Iviii, 1835, pp. 84—86). In
the description of his memorable ascent of Chimborazo (Ascension au
Ckimborazo le 16 Dec. 1831, loc. cit. p. 176), he says again:— "Like
Cotopaxi, Antisana, Tunguragua, and the volcanoes in general which pro-
ject from the plateaux of the Andes, the mass of Chimborazo is formed
by the accumulation of trachytic debris, heaped together without any
order. These fragments, often of enormous volume, have been elevated
in the solid state by elastic fluids which have broken out through the
points of least resistance ; their angles are always sharp." The cause
of earthquakes here indicated is the same as that which Hopkins calls
" a shock produced by the falling of the roof of a subterranean cavity,"
in his "Analytical Theory of Volcanic Phenomena" (Brit. Assoc. Report,
1847, p. 82).

15 Mallet, Dynamics of Earthquakes, pp. 74, 80, and 82 ; Hopkins,
Brit. Assoc. Report, 1847, pp. 74—82. All that we know of the waves
of commotion and oscillations in solid bodies shows the untenability of
the older theories as to the facilitation of the propagation of the move-
ment by a series of cavities. Cavities can only act a secondary part in
the earthquake, as spaces for the accumulation of vapours and con-
densed gases. " The earth, so many centuries old," says Gay Lussac
very beautifully (Ann. de Chimie et de Phys. tome xxii, 1823, p. 428),
" still preserves an internal force, which raises mountains (in the oxi-
dized crust), overturns cities and agitates the entire mass. Most moun-
tains, in issuing from the bosom of the earth, must have left vast cavi-
ties, which have remained empty, at least unless they have been filled
with water (and gaseous fluids). It is certainly incorrect for Deluc an<?
many geologists to make use of these empty spaces, which they imaghu
produced into long galleries, for the propagation of earthquakes to a
distance. These phenomena, so grand and terrible, are very powerful
sonoro\is waves, excited in the solid mass of the earth by some commo-
tion, which propagates itself therein with the same velocity as sound.
The movement of a carriage over the pavement shakes the vastest edi-
fices, and communicates itself through considerable masses, as in the
deep quarries below the city of Paris."

16 Upon phenomena of interference in the earth-waves, analogous to
those of the waves of sound, see Cosmos, vol. i, p. 211, Bohn'a edition,
and Humboldt, Kleinere Schriften, Bd. i. p. 379.

172 COSMOS

mathematically investigated. Attempts have been made to
reduce to a rectilineal*17 standard the apparently circling
(rotatory) shocks of which the obelisks before the monastery
of San Bruno, in the small town of Stephano del Bosco
(Calabria, 1783), furnished such a well-known example. Air,
water, and earth-waves follow the same laws which are re-
cognized by the theory of motion, at all events in space ; but
the earth-waves are accompanied, in their destructive action,
by phenomena which remain more obscure in their nature
and belong to the class of physical processes, As such we have
to mention, — discharges of elastic vapours, and of gases;
or, as in the small, moving Moya-cones of Pelileo, grit-like
mixtures of pyroxene crystals, carbon, and infusorial animal-
cules with silicious shields. These wandering cones have
overthrown a great number of Indian huts.18

In the general Delineation of Nature many facts are
narrated concerning the great catastrophe of Riobamba (4th
of February, 1797), which were collected on the spot from
the lips of the survivors, with the most earnest endeavours
after historic truth. Some of them are analogous to the
occurrences in the great earthquake of Calabria in the year
1783 ; others are new, and especially characterized l>y the
mine-like manifestation of force from below upwards. The
earthquake itself was neither accompanied nor announced by
any subterranean noise. A prodigious explosion, still indi-
cated by the simple name of el gran ruido, was not per-
ceived until 18 or 20 minutes afterwards, and only under
the two cities of Quito and Ibarra, far removed from Ta-
cunga, Hambato, and the principal scene of the destruc-
tion. There is no other event in the troubled destinies
of the human race, by which in a few minutes, and in
sparingly peopled mountain lands, so many thousands at
once may be overtaken by death, as by the production
and passage of a few earth-waves, accompanied by pheno-
mena of cleavage !

17 Mallet on vorticose shocks and cases of twisting, in Brit. Assoc.
Report, 1850, pp. 33 and 49, and in thf Admiralty Manual, 1849, p. 213
(see Cosmos, voL i, p. 199, Bonn's edition).

18 The Moya-cones were seen by Boussingault nineteen years after I
saw them. " Muddy eruptions, consequences of the earthquake, like
the eruptions of the Moya of P^lileo, which have buried entire villages**
(Ann. de Chim. et de Phys. t. lyiii, p. 81).

EARTHQUAKES. 173

In the earthquake of Biobamba, of which the celebrated
Valencian botanist, Don Jose Cavanilles, gave the earliest
account, the following phenomena are deserving of special
attention :— fissures which alternately opened and closed
again, so that men saved themselves by extending both
arms in order to prevent their sinking ; the disappearance
of entire caravans of riders or loaded mules (recuas), some of
which disappeared through transverse fissures suddenly open-
ing in their path, whilst others, flying back, escaped the
danger ; such violent oscillations (non-simultaneous elevation
iind depression) of neighbouring portions of the ground, that
people standing upon the choir of a church at a height of
more than 12 feet, got upon the pavement of the street
without falling ; the sinking of massive houses,19 in which the
inhabitants could open inner doors, and for two whole days,
before they were released by excavations, passed uninjured
from room to room, procured lights, fed upon supplies acci-
dentally discovered, and disputed with each other regarding
the probability of their rescue ; and the disappearance of
such great masses of stones and building materials. Old
Riobamba contained churches and monasteries amongst
houses of several stories ; and yet, when I took the plan of
the destroyed city, I only found in the ruins heaps of stone
of 8 to 10 feet in height. In the south-western part of Old
Hiobamba (the former Barrio de Sigchuguaicu) a mine-
like explosion, the effect of a force from below upwards, was
distinctly perceptible. On the Cerro de la Culca, a hill of
some hundred feet in height, which rises above the Cerro de
Cambicarca situated to the north of it, there lies stony rub-
bish mixed with human bones. Translator^ movements, in a
horizontal direction, by which avenues of trees become
displaced, without being uprooted, or fragments of culti-
vated ground of very different kinds mutually displace
each other, have occurred repeatedly in Quito, as well as

19 Upon the displacement of buildings and plantations during the
earthquake of Calabria, see Ly ell's Principles of Geology, vol. i, pp. 484
— 491. Upon escapes in fissures during the great earthquake of Rio-
bamba, see my Relation Historique, tome ii, p. 642. As a remarkable
example of the closing of a fissure it must be mentioned that, according
to Scacchi's report, during the celebrated earthquake (in the summer
of 1851), in the Neapolitan province of Basilicata, a hen was found
Caught by both feet in the street pavement in Barile, near Melfi,

174- COSMOS.

in Calabria. A still more remarkable and complicated phe-
nomenon is the discovery of utensils belonging to one
house in the ruins of another at a great distance ; a cir-
cumstance which has given rise to law-suits. Is it, as the
natives believe, a sinking followed by an eruption ? or,
notwithstanding the distance, a mere projection ? As,
in nature, everything is repeated when similar conditions
again occur, we must, by not concealing even what is still
imperfectly observed, call the attention of future observers
to special phenomena.

According to my observations it must not be forgotten that
besides the commotion of solid parts as earth-waves, very dif-
ferent forces, as for instance physical forces, emanations of
gas and vapour, also assist in most cases in the production of
fissures. When in the undulatory movement the extreme
limit of the elasticity of matter set in motion (according to
the difference of the rocks or the looser strata) is exceeded
and separation takes place, tense elastic fluid may break out
through the fissures, bringing substances of various kinds
from the interior to the surface and giving rise again by their
eruption to translatory movements. Amongst these pheno-
mena, which only accompany the primitive commotion (the
earthquake) are the elevation of the undoubtedly wandering
cone of the Moya, and probably also the transportation of
objects upon the surface of the earth.20 When large clefts
are formed, and these only close again at their upper parts,
the production of permanent subterranean cavities may not
only become the cause of new earthquakes, as, according to
Boussingault's supposition, imperfectly supported masses be-
come detached in course of time and fall, producing commo-
tions, but we may also imagine it possible that the circles of
commotion are enlarged thereby, and that in the new earth-
quake, the clefts opened in the previous one enable elastic
fluids to act in places to which they could not otherwise have
obtained access. It is therefore an accompanying pheno-

20 Cosmos, vol. i, p. 201, Bohn's edition. Hopkins has very correctly
shown theoretically that the fissures produced by earthquakes are very
instructive as regards the formation of veins and the phenomenon of
dislocation, the more recent vein displacing the older formations. But
long before Phillips (in his " Theorie der Gange," 1791), Werner
snowed the comparative ages of the displacing penetrating vein and oi
the disrupted penetrated rock (see Brit. Assoc. Report, 1847, p. 62).

EARTHQUAKES. 175

menon, and not the strength of the wave commotion which
has once passed through the solid parts of the earth, that
gives rise to the gradual and very important, but too little
considered enlargement of the circle of commotion?*

Volcanic activities, of which the earthquake is one of the
lower grades, almost always include at the same time, move-
ment and the physical production of matter. In the Deli-
neation of Nature we have already repeatedly indicated that
water and hot vapours, carbonic acid gas and other mofettes,
black smoke (as was the case for several days in the rock of
Alvidras during the earthquake of Lisbon on the 1st Novem-
ber, 1755), flames of fire, sand, mud and moyas mixed with
charcoal, rise from fissures at a distance from all volcanoes.
The acute geognosist, Abich, has proved the connexion which
exists in the Persian Ghilan between the thermal springs of
Sarcin (5051 feet), on the road from Ardebil to Tabriz, and
the earthquakes which frequently visit the elevated districts
in every second year. In October, 1 848, an uiidulatory move-
ment of the earth, which lasted for a whole hour, compelled
the inhabitants of Ardebil to abandon the town ; and the
temperature of the springs, which is between 44° and 46° C.
(= 111° — 115° F.) rose immediately to a most painful
scalding heat, and continued so for a whole month.22 As
Abich says, nowhere perhaps upon the face of the earth is
" the intimate connexion of fissure-producing earthquakes,
with the phenomena of mud- volcanoes, of salses, of combus-
tible gases penetrating through the perforated soil, and of

21 Upon the simultaneous commotion of the tertiary limestone of
Cumana and Maniquarez since the great earthquake of Cumana on the
14th December, 1796, see Humboldt's Relation Historique, tome i,
p. 314 ; Cosmos, vol. i, p. 208, Bonn's edition ; and Mallet, Brit. Assoc.
Report, 1850, p. 28.

^ Abich, on Daghestan, Schagdagh, and Ghilan, in Poggend. A nnalen,
Bd. Ixxvi, 1849, p. 157. The salt spring in a well near Sassendorf, in
Westphalia (in the district of Amsberg), also increased about l£ per
cent, in amount of saline matter, in consequence of the widely extended
earthquake of the 29th July, 1846, the centre of commotion of which
is placed at St. Goar, on the Rhine ; this was probably because other
fissures of supply had opened (Noggerath, Das Erdbeben im Rheinge-
biete vom 29 Juli, 1846, p. 14). According to Charpentier's observation,
the temperature of the sulphureous spring of Lavey (above St. Maurice,
on the bank of the Rhone), rose from 87°.8 to 97°.3 F. during the
Swiss earthquake of the 25th August, 1851.

175 cos;.;os.

petroleum springs, more distinctly expressed or more clearly
recognizable, than in the south-eastern extremity of the
Caucasus, between Schemacha, Baku, and Sallian. It is
the part of the great Aralo-Caspian basin, in which the earth
is most frequently shaken."23 I was myself struck with the
remarkable fact that in Northern Asia the circle of commo-
tion, the centre of which appears to be in the vicinity of Lake
Baikal, extends westwards only to the eastern borders of
the Russian Altai, as far as the silver mines of Riddersk,
the trachytic rock of Kruglaia Sopka and the hot springs of
Rachmanowka and Arachan, but not to the Ural chain.
Further, towards the south, on the other side of the parallel
of 45° 1ST., in the chain of the Thianschan (Mountains of
Heaven) there appears a zone of volcanic activity directed
from east to west, with every kind of manifestation. It
extends not only from the fire district (Ho-tscheu) in Tur-
fan, through the small chain of Asferah to Baku, and thence
over Ararat into Asia Minor ; but it is believed that it may
be traced, oscillating between the parallels of 38° and 40J JS .,
through the volcanic basin of the Mediterranean as far as
Lisbon and the Azores. I have elsewhere24 treated in detail

23 At Schemacha (elevation 2393 feet), one of the numerous meteoro-
logical stations founded by Prince Worouzow, in the Caucasus, under
Abich's directions, 18 earthquakes were recorded by the observer in
the journal in 1848 alone.

24 See Asie Centrale, tome i, pp. 324—329, and tome ii, pp. 108 —
120; and especially my Carte des Montagues et Volcans de I'Asie, com-
pared with the geognostic maps of the Caucasus, and of the plateau of
Armenia by Abich, and the map of Asia Minor (Argaeus) by Peter
Tschichatschef, 1853 (Rose, Reise nac/i dem Ural, Altai, und Kaspischem
Meere, Bd. ii, pp. 576 and 597). In Asie Centrale we find: — "From
Tourfan, situated upon the southern slope of the Thianchan, to the
Archipelago of the Azores, there are 120 degrees of longitude. This is
probably the longest and most regular band of volcanic reactions, oscil-
lating slightly between 38° and 40° of latitude, which exists upon the
face of the earth ; it greatly surpasses in extent the volcanic band of
the Cordillera of the Andes in South America. I insist the more upon
this singular line of ridges, of elevations, of fissures, and of propaga-
tions of commotions, which comprises a third of the circumference of a'
parallel of latitude, because some small accidents of surface, the un-
equal elevation and the breadth of the ridges, or linear elevations, a.s
well as the interruption caused by the sea-basins (Aralo-Caspian, Medi-
terranean, and Atlantic basins), tend to mark the great features
of the geological constitution of the globe. (This bold sketch of a
i-egnlarly prolonged line of commotion by no means excludes other

EARTHQUAKES -" 177

of this important subject of volcanic geography. In Greece,
also, which has suffered from earthquakes more than any
other part of Europe (Curtius, Peloponnesos, i, s. 42 — 46),
it appears that an immense number of thermal springs, some
still flowing, others already lost, have broken out with earth-
shocks. A similar thermic connexion is indicated in the re-
markable book of Johannes Lydus upon earthquakes (De
Ostentis, cap. liv, p. 189, Hase). The great natural pheno-
menon of the destruction of Helice and Bura in Achaia
(373 B.C. ; Cosmos, vol. iv, p. 543) gave rise in an especial
manner to hypotheses regarding the causal connexion of
volcanic activity. "With Aristotle originated the curious
theory of the force of the winds collecting in the cavities
of the depths of the earth (Meteor, ii, p. 368). By the part
which they have taken in the early destruction of the monu-
ments of the most flourishing period of the arts, the unhappy
frequency of earthquakes in Greece and Southern Italy has
exercised the most pernicious influence upon all the studies
which have been directed to the evolution of the Greek and
Roman civilisation at various epochs. Egyptian monuments
also, for example that of a colossal Memnon (27 years B.C.),
have suffered from earthquakes, which, as Letronne has
proved, have been by no means so rare as was supposed in
the valley of the Nile (Les Statues Vocales de M.emnony
1&33, pp. 23—27, 255).

The physical changes here referred to, as induced by earth-
quakes by the production of fissures, render it the more re-
lines in the direction of which the movements may also be propa-
gated.)" As the city of Khotan and the district south of the Thian-
echan has been the most ancient and celebrated seat of Buddhism, the
Buddhistic literature was occupied very early and earnestly with the
causes of earthquakes (see Foe-koue-ki, ou Relation des Royaumes Boud-
diques, translated by M. Abel Re"musat, p. 217). By the followers of Sak-
hyamuni eight of these causes are adduced, amongst which a revolving
wheel of steel, hung with reliques ('sarira, signifying body in Sanscrit),
plays a principal part, — a mechanical explanation of a dynamic phe-
nomenon, scarcely more absurd than many of our geological and mag-
netic myths, which have but recently become antiquated ! According
to a statement of Klaproth's, pnestd, and especially begging monks (Bhik-
*hous) have the power of causing the earth to tremble and of setting
the subterranean wheel in motion. The travels of Fahian, the author
of the t'oe-koue-ki, date about the commencement of the fifth cen-
tury.

VOL. V. M

178 COSMOS.

markable that so many warm mineral springs retain their
composition and temperature unchanged for centuries, and
therefore must flow from fissures which appear to have un-
dergone no alteration either vertically or laterally. The
establishment of communications with higher strata would
have produced a diminution, and that with lower ones an
increase of heat.

When the great eruption of the volcano of Conseguina (in
Nicaragua) took place on the 23rd of January, 1835, the
subterranean noise25 (los ruidos subterraneos) was heard at
the same time on the island of Jamaica and on the plateau
of Bogot£, 8740 feet above the sea, at a greater distance than
from Algiers to London. T have also elsewhere observed,
that in the eruptions of the volcano on the island of Saint
Vincent, on the 30th of April, 1812, at 2 o'clock in the
morning, a noise like the report of cannons was heard with-
out any sensible concussion of the earth over a space of
160,000 geographical square miles.8* It is very remarkable
that when earthquakes are combined with noises, which is
by no means constantly the case, the strength of the latter
does not at all increase in proportion to that of the former.
The most singular and mysterious phenomenon of subter-
ranean sound is undoubtedly that of the bramidos de Gua-
naxuato which lasted from the 9th of January to the middle
of February. 1784. regarding which I was the first to collect
trustworthy details from the lips of living witnesses, and
from official records (Cosmos, vol. i, p. 205).

The rapidity of the propagation of the earthquake upon
the surface of the earth must from its nature be modified in
many ways by the variable densities of the solid rocky strata
(granite and gneiss, basalt and trachytic porphyry, Jurassic
limestone and gypsum), as well as by that of the alluvial
soil, through which the wave of commotion passes. It

85 Acosta, Viajes cientificos d los Andes ecuatoriales, 1849, p. 56.

26 Cosmos, vol. i, pp. 204 — 206 ; Humboldt, Relation ffistorique,
t. iv, chap. 14, pp. 31 — 38. Some sagacious theoretical observations by
Mallet upon sonorous waves in the earth and sonorous waves in the air
occur in the Brit. Assoc. Report, 1850, pp. 41 — 46, and in the Admiralty
Manual, 1849, pp. 201 and 217. The animals which in tropical coun-
tries are disquieted by the slightest commotions of the earth sooner
than man are, according to my experience, fowls, pigs, dogs, asses, and
crocodiles (CajtnnuH); the latter suddenly quit the bottom D£ the riveru,

EARTHQUAKES. 179

would, however, be desirable to ascertain once for all with
certainty what are the extreme limits between which the
velocities vary. It is probable that the more violent com-
motions by no means always possess the greatest velocity.
The measurements, moreover, do not always relate to the
same direction which the waves of commotion have followed.
Exact mathematical determinations are much wanted, and
it is only at a very recent period that a result has been ob-
tained with great exactitude and care from the Rhenish
earthquake of the 29th of July, 1846, by Julius Schmidt,
assistant at the Observatory of Bonn. In the earthquake
just mentioned the velocity of propagation was 14,956
geographical miles in a minute, that is 1466 feet in the
second. This velocity certainly exceeds that of the waves of
sound in the air ; but if the propagation of sound in water
is at the rate of 5016 feet, as stated by Colladon and Sturm,
and in cast iron tubes 11393 feet, according to Biot, the
result found for the earthquake appears very weak. For
the earthquake of Lisbon on the 1st of November, 1755,
Schmidt (working from less accurate data) found the velocity
between the coasts of Portugal and Holstein to be more
than five times as great as that observed on the Rhine, on
the 29th of July, 1846. Thus, for Lisbon and Gluckstadt (a
distance of 1348 English miles) the velocity obtained was
89.26 miles in a minute or 7953 feet in a second ; which,
however, is still 3438 feet less than in cast iron.27

27 Julius Schmidt, in Nb'ggerath, Ueber das Erdbebcn vom 29 Juli,
1846, s. 28—37. With the velocity stated in the text, the earthquake
of Lisbon would have passed round the equatorial circumference of
the earth in about 45 hours. Michell (Phil. Transact, vol. i, pt. ii,
p. 572) found for the same earthquake of the 1st November, 1755, a
velocity of only 50 English miles in a minute, that is, instead of 7956,
only 4444 feet in a second. The inexactitude of the older obser-
vations and difference in the direction of propagation may conduce to
this result. Upon the connexion of Neptune with earthquakes, at
which I have glanced in the text (p. 181), a passage of Proclus in the
commentary to Plato's Cratylus, throws a remarkable light. " The
middle one of the three deities. Poseidon, is the cause of movement in
all things, even in the immovable. As the originator of movement he ia
called 'Eworriyaiog- to him, of those who shared the empire of Saturn,
fell the middle lot, the easily moved sea" (Creuzer, Symbolik und
Mythologie, Th. iii, 18.42, s. 260). As the Atlantis of Solon and the
Lyctonia, which, according to my idea, was nearly allied to it, are
geological myths, both the lands destroyed by earthquakes are re*

K 2

180 COSMOS.

Concussions of the earth and sudden eruptions of fire
from volcanoes which have been long in repose, whether
these merely emit cinders, or, like intermittent springs,
pour forth fused, fluid earths in streams of lava, have cer-
tainly a single, common causal connexion in the high
temperature of the interior of our planet ; but one of these
phenomena is usually manifested quite independently of the
other. Thus, in the chain of the Andes in its linear exten-
sion, violent earthquakes shake districts in which unextin •
guished, often indeed active, volcanoes exist, without the lat-
ter being perceptibly excited. During the great catastrophe
of Riobamba, the volcanoes of Tungurahua and Cotopaxi, the
former in the immediate \icinity, and the latter rather fur-
ther off, remained perfectly quiet. On the other hand, vol-
canoes have presented violent and long-continued eruptions,
without any earthquake being perceived in their vicinity,
either previously or simultaneously. In fact, the most de-
structive earthquakes recorded in history, and which have
passed through many thousand square miles, if we may judge
from what is observable at the surface, stand in no connexion
with the activity of volcanoes. These have lately been called
Plutonic, in opposition to the true Volcanic earthquakes,
which are usually limited to smaller districts. In respect of
the more general views of vulcanicity, this nomenclature is,
however, inadmissible. By far the greater part of the earth-
quakes upon our planet must be called Plutonic.

That which is capable of exciting earth-shocks, is every-
where under our feet ; and the consideration that nearly
|ths of the earth's surface are covered by the sea (with
the exception of some scattered islands) and without any
permanent communication between the interior and the
atmosphere, that is to say, without active volcanoes, contra-
dicts the erroneous, but widely disseminated belief that all
earthquakes are to be ascribed to the eruption of some dis-
tant volcano. Earthquakes on continents are certainly propa-

garded as standing under the dominion of Neptune, and Bet in opposi-
tion to the Saturnian continents. According to Herodotus (lib. ii,
c. 43 et 50), Neptune was a Libyan deity, and unknown in Egypt.
Upon these circumstances — the disappearance of the Libyan lake
Tritonis by earthquake — and the idea of the great rarity of earthquakes
in the valley of the Nile, see my Examen Critique de la Geograjjlue, t. i,
pp. 171 and 172.

EARTHQUAKES. 181

gated along the sea-bottom from the shores, and give rise to
the terrible sea-waves, of which such memorable examples
were furnished by the earthquakes of Lisbon, Callao de Lima,
and Chili. When, on the contrary, the earthquakes start
from the sea bottom itself, from the realm of Poseidon, the
earth-shaker (^ffeiai^Owv, Kivrjot^Owv), and are not accom-
panied by upheaval of islands (as in the ephemeral exist-
ence of the island of Sabrina or Julia), an unusual rolling
and swelling of the waves may still be observed at points
where the navigator would feel no shock. The inhabitants of
the desert Peruvian coasts have often called my attention to
a phenomenon of this kind. Even in the harbour of Callao,
and near the opposite island of San Lorenzo, I have seen,
wave upon wave suddenly rising up in the course of a few
hours to more than 10 or 15 feet, in perfectly still nights,
and in this otherwise so thoroughly peaceful part of the South
Sea. That such a phenomenon might have been the conse-
quence of a storm which had raged far off upon the open sea,
was by no means to be supposed in these latitudes.

To commence from those commotions which are limited
to the smallest space, and evidently owe their origin to the
activity of a volcano, I may mention in the first place how
when sitting at night in the crater of Vesuvius at the foot
of a small cone of eruption with my chronometer in my hand,
(this was after the great earthquake of Naples on the 26th of
July, 1805, and the eruption of lava which took place seven-
teen days subsequently), I felt a concussion of the soil of
the crater very regularly every 20 or 25 seconds, imme-
diately before each eruption of red hot cinders. The cinders,
thrown up to a height of 50 — 60 feet fell back partly into
the orifice of eruption, whilst a part of them covered the
walls of the cone. The regularity of such a phenomenon
renders its observation free from danger. The constantly
repeated small earthquake was quite imperceptible beyond
the crater, — even in the Atrio del Cavallo and in the Her-
mitage del Salvatore. The periodicity of the concussion
shows that it was dependent upon a determinate degree of
tension which the vapours must attain, to enable them to
break through the fused mass in the interior of the cone
of cinders. In the case just described no concussions were
telt on the declivity of the ashy cone of Vesuvius, and in an

182 COSMOS.

exactly analogous but far grander phenomenon, on the ash-
cone of the volcano of Sangai, which rises to a height of
17,006 feet to the south-east of the city of Quito, no trem-
bling of the earth28 was felt by a very distinguished observer,
M. Wisse, when (in December, 1849,) he approached within
a thousand feet of the summit and crater, although no less
than 267 explosions (eruptions of cinders) were counted in
an hour.

A second, and infinitely more important kind of earth-
quake, is the very frequent one which usually accompanies
or precedes great eruptions of volcanoes,— whether the vol-
canoes, like ours in Europe, pour forth streams of lava ; or
like Cotopaxi, Pichincha, and Tunguragua of the Andes
only throw out calcined masses, ashes and vapours. For
earthquakes of this kind the volcanoes are especially to be
regarded as safety valves, as indicated even by Strabo's ex-
pression concerning the fissure pouring out lava near Lelante
in Eubcea. The earthquakes cease, when the great eruption
has taken place.

Most widely29 distributed, however, are the ravages of the
waves of commotion which pass sometimes through completely
non-trachytic, non-volcanic countries and sometimes through

28 The explosions of the Sangai, or Volcan de Macas, took place on
an average every 13". 4, see Wisse, Comptes rendus de I'Acad. des
Sciences, tome xxxvi, 1853, p. 720. As an example of commotions con-
fined within the narrowest limits, I might also have cited the report of
Count "Larderel upon the lagoons in Tuscany. The vapours containing
boron or boracic acid give notice of their existence and of their ap-
proaching eruption at fissures by shaking the surrounding rocks (Lar-
derel, Sur les etablissements industries de la production d'acide boracique
en Toscane, 1852, p. 15).

29 I am glad that I am able to cite an important authority in confir-
mation of the views that I have endeavoured to develope in the text.
" In the Andes the oscillation of the soil, due to a volcanic eruption,
is, so to speak, local, whilst an earthquake, which, at all events in ap-
pearance, is not connected with any volcanic eruption, is propagated to
incredible distances. In this case it has been remarked that the
shocks followed in preference the direction of the chains of mountains,
and were principally felt in Alpine districts. The frequency of the
movements in the soil of the Andes, and the little coincidence observed
between these movements and volcanic eruptions, must necessarily lead
us to suppose that in most cases they are occasioned by a cause inde-
pendent of volcanoes" (Boussingault, Annales de Chimie et de Physique,
t. Iviii, 1835, p. 83).

EARTHQUAKES. 183

krachytic, volcanic regions, without exerting any influence
upon the neighbouring volcanoes. This is a third group of
phenomena, and is that which most convincingly indicates
the existence of a general cause, lying in the thermic nature
of the interior of our planet. To this third group also be-
longs the phenomenon, sometimes, though rarely, met with
in non-volcanic lands, but little disturbed by earthquakes,
of a trembling of the soil, within the most narrow limits,
continued uninterruptedly for months together, so as to give
rise to apprehensions of an elevation and formation of an
active volcano. This was the case in the Piedmontese val-
leys of Pelis and Clusson, as well as in the vicinity of Pig-
nerol in April and May, 1805, and also in the spring of 1829
in Murcia, between Orihuela and the sea-shore, upon a space
of scarcely sixteen square miles. When the cultivated sur-
face of Jorullo upon the western declivity of the plateau of
Mechoacan in the interior of Mexico was shaken uninter-
ruptedly for 90 days, the volcano rose with many thousand
cones of 5—7 feet in height (los Jwrnitos) surrounding it.
and poured forth a short but vast stream of lava. In Pied-
mont and Spain, on the contrary, the concussions of the
oarth gradually ceased, without the production of any other
phenomenon.

I have considered it expedient to enumerate the perfectly
distinct kinds of manifestation of the same volcanic activity
(the reaction of the interior of the earth upon its surface)
in order to guide the observer, and bring together materials
which may lead to fruitful results with regard to the causal
connexion of the phenomena. Sometimes the volcanic
activity embraces at one time or within short periods sc
large a portion of the earth, that the commotions of the soil
excited may be ascribed simultaneously to many causes re
lated to each other. The years 1796 and 1811 present par-
ticularly memorable examples 30 of such a grouping of the
phenomena,

30 The great phenomena of 1796 and 1797, and 1811 and 1812,
occurred in the following order : —

27th of September, 1796. Eruption of the volcano of the island of

Quadaloupe, in the Leeward Islands, after a repose of many years
November, 1796. The volcano on the plateau of Pasto, between

the small rivers Guaytara and Juanambu, became ignited and

began to smoke permanently ;

184 COSMOS.

b, Thermal Springs.

(Amplification of the Representation of Nature.
Cosmos, vol. i, pp. 216—221).

Asa consequence of the vital activity of the interior of
our planet, evidenced in irregularly repeated and often
tearfully destructive phenomena, we have described the

14th of December, 1796. Earthquake and destruction of the city of
Cumana ;

4th of February, 1797. Earthquake and destruction of Rjobamba. On
the same morning the columns of smoke of the volcano of Pasto,
at a distance of at least 200 geographical miles from Riobamba,
disappeared suddenly, and never reappeared ; no commotion was
felt in its vicinity.

30th of January, 1811. First appearance of the island of Sabrina, in
the group of the Azores, near the island of St. Michael. The ele-
vation preceded the eruption of fire, as in the case of the little
Kameni (Santorin) and that of the volcano of Jorullo. After an
eruption of cinders, lasting for six days, the island rose to a
height of 320 feet above the surface of the sea. It was the
third appearance and disappearance of the island nearly at the
same point, at intervals of 91 and 92 years.

Iffay, 1811. More than 200 shocks of earthquake on the island of
St. Vincent up to April, 1812.

December, 1811. Innumerable shocks in the river-valleys of the
Ohio,^ Mississippi, and Arkansas up to 1813. Between New
Madrid, Little Prairie, and La Saline, to the north of Cincin-
nati, the earthquakes occurred almost every hour for months
together.

December, 1811. A single shock in Caraccas.

26th of March, 1812. Earthquake and destruction of the town of
Caraccas. The circle of commotion extended over Santa Mart a,
the town of Honda, and the elevated plateau of Bogota", to a dis-
tance of 540 miles from Caraccas. The motion continued until the
middle of the year 1813.

80th of April, 1812. Eruption of the volcano of St. Vincent ; and on
the same day, about 2 o'clock in the morning, a fearful subter-
ranean noise, like the roar of artillery, was heard at the same time
and with equal distinctness on the shores of Caraccas, in the
Llanos of Calabazo and of the Rio Apure, without being accom-
panied by any concussion of the earth (see ante, p. 178). The
subterranean noise was also heard upon the Island of St. Vin-
cent, but, and this is very remarkable, it was stronger at some
distance upon the sea.

THERMAL SPRINGS. 185

earthquake. In this, there prevails a volcanic power, which
in its essential nature only acts dynamically, producing
movement and commotion, but when it is favoured at parti-
cular points by the fulfilment of subsidiary conditions, it is
capable of bringing to the surface material products, although
not of generating them like true volcanoes. Just as water,
vapours, petroleum, mixtures of gases, or pasty masses (mud
and moya} are thrown out, through fissures suddenly opened
in earthquakes sometimes of short duration, so do liquid and
aerial fluids flow permanently from the bosom of the earth
through the universally diffused network of communicating
fissures. The brief and impetuous eruptive phenomena are
here placed beside the great peaceful spring-system of the
crust of the earth, which beneficently refreshes and supports
organic life. For thousands of years it returns to organized
nature the moisture which has been drawn from the atmo-
sphere by falling rain. Analogous phenomena are mutually
illustrative in the eternal economy of nature ; and wherever
an attempt is made at the generalisation of ideas, the inti-
mate concatenation of that which is recognized as allied must
not remain unnoticed.

The widely disseminated classification of springs, into
cold and hot, which appears so natural in ordinary conversa-
tion, has but a very indefinite foundation when reduced
to numerical data of temperature. If the temperature of
springs be compared with the internal heat of man (found,
with thermo-electrical apparatus, to be 98° — 98°. 6 F. according
to Brechet and Becquerel), the degree of the thermometer at
which a fluid is called cold, warm, or hot, when in contact
with parts of the human body, is very different according to
individual sensations. No absolute degree of temperature
can be established, above which #, spring should be desig-
nated warm. The proposition to call a spring cold in any
climatic zone, when its average annual temperature does not
exceed the average annual temperature of the air in the sama
zone, at least presents a scientific exactitude, by affording a
comparison of definite numbers. It has the advantage of lead-
ing to considerations upon the different origin <?f springs, as
the ascertained agreement of their temperature with the
annual temperature of the air is recognized directly in un-
changeable springs; and in changeable ones, as has beeu

186 COSMOS. •

shown by TVahlenberg and Erman the elder, in the averages
of the summer and winter months. But in accordance with
the criterion here indicated, a spring in one zone must be
denominated warm, which hardly attains the seventh cr
eighth part of temperature of one which in another zone,
near the equator, will be called cold. I may mention the
differences between the average temperature of St. Peters-
burg (38°.12 F.) and of the shores of the Orinoco. The
purest spring water which I drank in the vicinity of the
cataracts of Atures31 and Maypures (81°. 14 F.) or in the
forest of Atabapo, had a temperature of more than 79° F. ;
even the temperature of the great rivers in tropical South
America, corresponds with the high degrees of heat of such
cold32 springs.

31 Humboldt, Voyage aux Regions Equinoxiales, t. ii, p. 376.

32 Foi the sake of comparing the temperature of springs where they
break fort»i directly from the earth, with that of large rivers flowing
through open channels, I here bring together the following average
numbers from my journals : —

Rio Apure, lat. 7f° ; temperature, 81°.

Orinoco, between 4° and 8° of latitude ; 81°.5— 85°.3.

Springs in the forest, near the cataract of Maypures, breaking forth
from the granite, 82°.

Cassiquiare, the branch of the Upper Orinoco, which forms the union
with the Amazon; only 75°.7.

Rio Negro, above San Carlos (scarcely 1° 53' to the north of the
equator); only 74°. 8.

Rio Atabapo, 79°.2 (lat. 3° 500-

Orinoco, near the entrance of the Atabapo, 82°.

Rio Grande de la Magdalena (lat. 5° 12' to 9° 56'), 79° 9'.

Amazon, 5° 31' south latitude, opposite to the Pongo of Rentema
(Provincia Jaen de Bracamoros), scarcely 1300 f 'et above ths
South Sea, only 72°. 5.

The great mass of water of the Orinoco consequently pproaches the
average temperature of the air of the vicinity. During great inunda-
tions of the Savannahs, the yellowish brown waters, which smell of
sulphuretted hydrogen, acquire a temperature of 92°. 8 ; this I found to
be the temperature in the Lagartero,to the east of Guayaqtiil, which
swarmed with crocodiles. The soil there becomes heated, as in shallow
rivers, by the warmth produced in it by the sun's rays falling upon it.
With regard to the multifarious causes of the low temperature of the
water of the Rio Negro, which is of a coffee-brown colour by reflected
light, and of the white waters of the Cassiquiare (a constantly clouded
eky, the quantity of rain, the evaporation from the dense forests, and

THERMAL SPRINGS. 187

The breaking out of springs, effected by multifarious
causes of pressure and by the communication of fissures
containing water, is such a universal phenomenon of the
surface of the earth, that waters flow forth at some points
from the most elevated mountain strata, and at others from
the bottom of the sea. In the first quarter of this century
numerous results were collected by Leopold von Buch,
Wahlenberg and myself, with regard to the temperature
of springs and the diffusion of heat in the interior of the
earth in both hemispheres, from 12° S. lat. to 71° N.33 The
springs which have an unchangeable temperature were care-
fully separated from those which vary with the seasons ;
and Leopold von Buch ascertained the powerful influence
of the distribution of rain in the course of the year, that is
to say, the influence of the proportion between the relative
abundance of winter and summer rain upon the temperature
of the variable springs, which, as regards number, are the
most widely distributed. More recently34 some very ingenious

the want of hot sandy tracts upon the banks), see my river voyage, in
the Relation Historique, t. ii, pp. 463 and 509. In the Rio Guanca-
bamba or Chamaya, which falls into the Amazon, near the Pongo de
Rentema, I found the temperature of the water to be only 67°.6, as its
waters come with prodigious swiftness from the elevated lake Sirni-
cocha on the Cordillera. On my voyage of 52 days up the river Mag-
dalena, from Mahates to Honda, I perceived most distinctly, from
numerous observations, that a rise in the level of the water was indi-
cated for hours previously by a diminution of the temperature of the
river. The refrigeration of the stream occurred before the cold moun-
tain waters from the Paramos near the source came down. Heat and
water move, so to speak, in opposite directions and with very unequal
velocities. When the water near Badillas rose suddenly, the tempera-
ture fell long before from 80°.6 to 74°.3. As, during the night, when
one is established upon a low sandy islet, or upon the bank, with bag
and baggage, a rapid rise of the river may be dangerous, the dis-
co veiy of a prognostic of the approaching rise (the avenida) is of some
importance.

33 Leopold von Buch, Physicalisclie BescJireibung der canarischen
Inseln, s. 8 : Poggend. Annalen, Bd. xii, s. 403 ; Bibliotheque Britan-
nique, Sciences et Arts, t. xix, 1802, p. 263 ; Wahlenberg, De Veget. et
Glim, in Helvetia Septentrionali Observatis, pp. Ixxviii and Ixxxiv ;
Wahlenberg, Flora Carpathica, p. xciv, and in Gilbert's Annalen,
Bd. xli, s. 115 ; Humboldt, in the Mem. de la Soc. d'Arcucil, t. iii (1817)
p. 599.

34 De Gasparin, in the Bibliotheque Univ. Sciences et Arts, t. xxxviii,
1828, pp. 54, 113 and 264 ; Mem. de la Soc. Centrale d 'Agriculture,

188 COSMOS.

comparative observations by De Gasparin, Schouw and Thur-
mann have thrown considerable light, in a geographical and
hypsometrical point of view, in accordance with latitude and
elevation upon this influence. Wahlenberg asserted that in
very high latitudes the average temperature of variable springs
is rather higher than that of the atmosphere ; he sought the
cause of this, not in the dryness of a very cold atmosphere and
in the less abundant winter rain caused thereby, but in the
snowy covering diminishing the radiation of heat from the soil.
In those parts of the plain of Northern Asia, in which a
perpetual icy stratum, or at least a frozen alluvial soil mixed
with fragments of ice is found at a depth of a few feet,85 the
temperature of springs can only be employed with great cau-
tion for the investigation of Kupffer's important theory of
the isogeothermal lines. A two-fold radiation of heat is
then produced in the upper stratum of the earth : one up-
wards towards the atmosphere, and another downwards
towards the icy stratum. A long series of valuable observa-
tions made by my friend and companion, Gustav Rose, during
our Siberian expedition in the heat of summer (often in
springs still surrounded by ice) between the Irtysch, the
Obi, and the Caspian Sea, revealed a great complication of
local disturbances. Those which present themselves from
perfectly different causes in the tropical zone, in places where

1826, p. 178; Schouw, Tableau du Ciimat et de la Vegetation de TItalie
vol. i, 1839, pp. 133 — 195 ; Thurmann, Sur la temperature des sources de
l(t chatne du Jura, comparee a ceUe des sources de la plaine Suisse, des
Alpes et des Vosges, in the Annuaire Meteor ologique de la France, 1850,
Plj. 258 — 268. As regards the frequency of the summer and autumn
rains, De Gasparin divides Europe into two strongly contrasted regions.
Valuable materials are contained in Kamtz, Lehrbuch der Meteorologie,
Bd. i, s. 448 — 506. According to Dove (Poggend. Annalen, Bd.
xxxv, s. 376) in Italy. " at places to the north of which a chain of
mountains is situated, the maxima of the curves of monthly quantities
of rain fall in March and September ; and where the mountains lie to
the south, in April and October." The totality of the proportions of
rain in the temperate zones may be comprehended under the following
general point of view : — " The period of winter rain in the borders of
the tropics constantly divides, the further we depart fi'om these, into
two maxima united by slighter falls, and these again unite into a
summer-maximum in Germany; where, therefore, a temporary want of
rain ceases altogether." See the section "Geothermik" in the excellent
Lehrbuch der Geoynosie, by Naumaun, Bd. i, (1850), s. 41—73.
35 See above, p. 45.

THERMAL SPRINGS. 189

•mountain springs burst forth upon vast elevated plateaux,
eight or ten thousand feet above the sea (Micuipampa,
Quito, Bogota), or in narrow, isolated mountain-peaks many
thousand feet higher, not only include a far greater part of
the surface of the earth, but also lead to the consideration
of analogous thermic conditions in the mountainous countries
of the temperate zones.

In this important subject it is above all things necessary
to separate the cycle of actual observations from the theor-
etical conclusions which are founded upon them. What we
seek, expressed in the most general way, is of a triple nature :
— the distribution of heat in the crust of the earth which is
accessible to us, in the aqueous covering (the ocean) and in
the atmosphere. In the two envelopes of the body of the
earth, the liquid and gaseous, an opposite alteration of tem-
perature (diminution and increase in the superposed strata)
prevails in a vertical direction. In the solid parts of the
body of the earth the temperature increases with the depth ;
the alteration is in the same direction, although in a very
different proportion, as in the aerial ocean, the shallows and
rocks of which are formed by the elevated plateaux and mul-
tiform mountain peaks. We are most exactly acquainted
by direct experiments, with the distribution of heat in the
atmosphere, — geographically by local determination in lati-
tude and longitude, and in accordance with hypsometric re-
lations in proportion to the vertical elevation above the sur-
face of the sea, — but in both cases almost exclusively in
close contact with the solid and fluid parts of the surface of
our planet. Scientific and systematically arranged investi-
gations by aerostatic voyages in the free aerial ocean, beyond
the near action of the earth, are still very rare, and there-
fore but little adapted to furnish the numerical data of
average conditions which are so necessary. Upon the de-
crease of heat in the depths of the ocean observations are
not wanting ; but currents, which bring in water of different
latitudes, depths, and densities, prevent the attainment of
general results, almost to a greater extent than currents in
the atmosphere. We have here touched preliminarily upon
the thermic conditions of the envelopes of our planet, which
will be treated of in detail hereafter, in order to consider the
influence of the vertical distribution of heat in the solid

190 COSMOS.

crust of the earth, and the system of the geo-isothermic
lines, not in too isolated a condition, but as a part of the
all-penetrating motion of heat, a truly cosmical activity.

Instructive as are, in many respects, observations upon
the unequal diminution of temperature of springs which do
not vary with the seasons as the height of their point of
emergence increases, — still the local law of such a diminish-
ing temperature of springs cannot be regarded, as is often
done, as a universal geothermic law. If we were certain
that waters flowed unmixed in a horizontal stratum of great
extent, we might certainly suppose that they have gradually
acquired the temperature of the solid ground, but in the
great network of fissures of elevated masses, this case can
rarely occur. Colder and more elevated waters mix with
the lower ones. Our mining operations, inconsiderable as
may be the depth to which they attain, are very instruc-
tive in this respect ; but we should only obtain a direct
knowledge of the isogeothermal lines, if thermometers were
buried, according to Boussingault's method,36 to a depth below
that affected by the influences of the changes of temperature
of the neighbouring atmosphere, and at very different eleva-
tions above the sea. From the forty-fifth degree of latitude
to the parts of the tropical regions in the vicinity of the
equator, the depth at which the stratum of invariable tempe-
rature commences, diminishes from 60 to 1^ or 2 feet. Bury-
ing the geothermometer at a small depth in order to obtain a
knowledge of the average temperature of the earth, is there-
fore readily practicable only between the tropics or in the
subtropical zone. The excellent expedient of Artesian wells
which have indicated an increase of heat of 1° F. for every
54 to 58 feet in absolute depths of from 745 to 2345
feet has hitherto only been afforded to the physicist in
districts not much more than 1600 feet above the level of
the sea 37 I have visited silver-mines in the chain of the
Andes, 6°45' south of the equator at an elevation of nearly
13,200 feet and found the temperature of the water pene-
trating through the fissures of the limestone to be 52°,3 F.88
The waters which were heated in the baths of the Inca

36 See Cosmos, vol. i, p. 218, and vol. v, p. 40, Bohn's edition.

*7 See above, p. 37.

88 Mina de Guadalupe, one of the Minas de Chota, I.e. sup. p. 43,

THERMAL SPRINGS. 191

Tupac Yupanqui, upon the ridge of the Andes (Paso del
Assuay}, probably come from springs of the Lad era de Cad-
lud, where I have traced their course, near which the old
Peruvian causeway also ran, barometrically to an elevation
of 15,526 feet (almost that of Mont Blanc).39 These are the
highest points at which I could observe spring water in
South America. In Europe the brothel's Schlagintweit
have found gallery-water in the gold mine in the Eastern
Alps at a height of 9442 feet, and found that the tempera-
ture of small springs near the opening of the gallery of only
33°.4 F.,40 at a distance from any snow or glacier ice. The
highest limits of springs are very different according to geo-
graphical latitude, the elevation of the snow line and the rela-
tion of the hi^Uest peaks to the mountain ridges and plateaux.
If the radius of our planet were to be increased by the
height of the Himalaya at the Kintschindjun^a, and there-
fore uniformly over the whole surface by 28,175 feet (4.34
English miles), with this small increase of only -g-roth
of the radius, the heat in the surface cooled by radiation,
would be (according to Fourier's analytical theory), almost
the same as it now is in the upper crust of the earth.
But if individual parts of the surface raise themselves in
mountain chains and narrow peaks, like rocks upon the
bottom of the aerial ocean, a diminution of heat takes place
in the interior of the elevated strata, and this is modified
by contact with strata of air of different temperature, by the
capacity for heat and conductive power of heterogeneous
kinds of rocks, by the sun's action on the forest-clad
summits and declivities, by the greater and less radiation
of the mountains in accordance with their form (relief),
their massiveness) or their conical and pyramidal narrow-
ness. The special elevations of the region of clouds, the
snow and ice-coverings at various elevations of the snow
line, and the frequency of the cool currents of air coming
down the steep declivities, at particular times of the day, alter
the effect of the terrestrial radiation. In proportion as the
towering cones of the summits become cooled, a weak current

» Hximboldt, Views of Nature, p. 393.

40 Mine on the Great Fleuss in the Moll Valley of the Tauern, se«
Hermann and Adolph Schlagintweit, Untersuchungen iOter die physifa-
liwhe Geographic 1#r Alzen, 1850, s. 242—273.

192 COSMOS.

of heat tending towards, but never reaching an equilibrium,
sets in from below upwards. The recognition of so many
factors acting upon the vertical distribution of heat, leads to
well-founded presumptions regarding the connexion of com-
plicated local phenomena, but not to direct numerical deter-
minations. In the mountain springs (and the higher ones,
being important to the chamois-hunter, are carefully sought)
there so often remains the doubt that they are mixed with
waters, which by sinking down introduce the colder tem-
perature of higher strata, or by ascending introduce the
warmer temperature of lower strata. From 19 springs, ob-
served by Wahlenberg, Kamtz draws the conclusion that in
the Alps we must rise from 960 to 1023 feet in order to *ee
the temperature of the springs sink 1° C. (1°.8 F.). A greater
number of observations selected with more care by Hermann
and Adolph Schlagintweit in the eastern Carinthian Alps
and in the western Swiss Alps on the Monte Rosa, give only
767 feet. According to the great work41 of these excellent
observers, " the decrease of the temperature of springs is
certainly somewhat more gradual than that of the average
annual temperature of the air, which in the Alps amounts
to about 320 feet for 1° F. The springs there are in
general warmer than the average temperature of the air at
the same level ; and the difference between the temperature
of the air and springs increases with the elevation. The
temperature of the soil is not the same at equal elevations
in the entire range of the Alps, as the isothermal surfaces
which unite the points of the same average temperature of
springs, rise higher above the level of the sea, independently
of the influence of latitude, in proportion to the average con-
vexity of the surrounding soil ; perfectly in accordance with
the laws of the distribution of heat in a solid body of vary-
ing thickness, with which the relief (the mass-elevation) of
the Alps may be compared."

In the chain of the Andes, and indeed in those volcanic
parts of it which present the greatest elevations, the bury-
ing of thermometers may in particular cases lead to decep-
tive results by the influence of local circumstances. From
the opinion formerly held by me, that black rocky ridges,
visible at a great distance, which penetrate the snowy
41 Monte Rosa, 1853, chap, vi, s. 212—225.

THERMAL SPRINGS. 193

region, are not always indebted for their entire freedom
I'rom snow to the steepness of their sides, but to other
causes, I buried the bulb of a thermometer only three inches
deep in the sand which filled the fissure in a ridge on the
Chimborazo at an elevation of 18,290 feet, and therefore
3570 feet above the summit of Mont Blanc. The thermo-
meter permanently showed 10°.5 F. above the freezing point,
whilst the air was only 4°.5 F. above that point. The re-
sult of this observation is of some importance ; for even
2558 feet lower, at the lower limit of perpetual snow of the
volcano of Quito, according to numerous observations col-
lected by Boussingault and myself, the average temperature
of the atmosphere is not higher than 34°. 9 F. The ground
temperature of 42^.5 must therefore be ascribed to the sub-
terranean heat of the doleritic mountain : I do not say of
the entire mass, but to the currents of air ascending in it
from the depths. At the foot of Chimborazo, at an eleva-
tion of 9486 feet towards the hamlet of Calpi, there is, more-
over, a small crater of eruption, Yana-Urcu, which, as indeed
is shown by its black, slag-like rock (augitic -porphyry), ap-
pears to have been active in the middle of the fifteenth cen-
tury.48

The aridity of the plain from which Chimborazo rises,
and the subterranean brook, which is heard rushing under
the volcanic hill (Yana-Urcu) just mentioned, have led
Boussingault and myself43 at very different times to the idea
that the water which the enormous masses of snow produce
daily by melting at their lower limit, sinks into the depths
through the fissures and chambers of the elevated volcano.
These waters perpetually produce a refrigeration in the
.strata through which they run down. Without them the
whole of the doleritic and trachytic mountains would ac-
quire, even at times when no near eruption is foretold, a still
higher temperature in their interior, from the volcanic
source, perpetually in action, although perhaps not lying at
the same depth in all latitudes. Thus, in the varying
struggle of the causes of heat and cold, we have to assume
a constant tide of heat upwards and downwards in those
places where conical solid parts ascend into the atmosphere.

4J Humboldt, Kleinere Schriften, Ed. i, pp. 139 and 147.

'•' Humboldt, Op. tit., s. 140 and 203.

VOL. V. O

194 COSMOS.

As regards the area which they occupy, however, mountains
and elevated peaks form a very small phenomenon in the relief
formation of continents ; and moreover nearly two-thirds of
the entire surface of the earth is sea-bottom (according to
the present state of geographical discovery in the polar re-
gions of both hemispheres, we may assume the proportion of
sea and land to be in the ratio of 8 : 3). This is directly in
contact with aqueous strata, which, being slightly salt, and
depositing themselves in accordance with the maximum of
their density (at 38°.9), possess an icy coldness. Exact ob-
servations by Lenz and du Petit-Thouars have shown that
within the tropics, where the temperature of the surface of the
ocean is 78°.8 to 80°.6, water of the temperature of 36°.5 could
be drawn up from a depth of seven or eight hundred fathoms,
— phenomena which prove the existence of under currents
from the polar regions. The consequences of tliis constant,
suboceanic refrigeration of by far the greater part of the
crust of the earth deserve a degree of attention which they
have not hitherto received. JRocks and islands of small size,
which project, like cones, from the sea-bottom above the sur-
face of the water, and narrow isthmuses, such as Panama and
Darien washed by great oceans, must present a distribution
of heat in their rocky strata, different from that of parts of
equal circumference and mass in the interior of continents.
In a veiy elevated mountainous island, the submarine part is
in contact with a fluid which has an increasing temperature
from below upwards. But as the strata pass into the atmo-
sphere, unmoistened by the sea, they come in contact, under
the influence of insolation and free radiation of dark heat,
with a gaseous fluid in which the temperature diminishes
with the elevation. Similar thermic conditions of opposed
decrease and increase of temperature in a vertical direction
are repeated between two large inland seas, the Caspian and
Aral Sea, in the narrow Ust-tJrt, which separates them from,
each other. In order, however, to clear up such compli-
cated phenomena, the only means to be employed are such
as borings of great depth, which lead directly to the know-
ledge of the internal heat of the earth, and not merely ob-
servations of springs, or of the temperature of the air in
caves, which give just as uncertain results as the air in the
galleries arid chambers of mines.

THERMAL SPRINGS. 195

\Vlien a low plain is compared with a mountain chain or
plateau, rising boldly to a height of many thousand feet, the
law of the increase and diminution of temperature does not
depend simply upon the relative vertical elevation of two
points on the earth's surface (in the plain and on the summit
of the mountain). If we should calculate from the supposi-
tion of a definite proportion in the change of temperature in
a certain number of feet from the plain upwards to the sum-
mit, or from the summit downwards to the stratum in the
interior of the mountain mass which lies at the same level
as the surface of the plain, we should in the one case find the
summit too cold, and in the other the stratum in the in-
terior of the mountain far too hot. The distribution of
heat in a gradually sloping mountain (an undulation of the
surface of the earth) is dependent, as has already been re-
marked, upon form, mass, and conductibility ; upon insola-
tion, and radiation of heat towards the clear or cloudy
strata of the atmosphere ; and upon the contact and play
of the ascending and descending currents of air. According
to such assumptions, mountain springs must be very abun-
dant, even at very moderate elevations of four or five ^hou-
sand feet, where the temperature would exceed the average
temperature of the locality by 72 or 90 degrees ; and how
would it be at the foot of mountains under the tropics,
which at an elevation of 14,900 feet are still free from
perpetual snow ; and often exhibit no volcanic rock, but
only gneiss and mica schist I44 The great mathematician,
Fourier, who had been much interested in the fact of the
volcano of Jorullo having been upheaved, in a plain, where
for many thousands of square miles around no unusual ter-
restrial heat was to be detected, occupied himself at my
request in the very year before his death with theoretical
investigations upon the question, how in the elevation of
mountains and alterations in the surface of the earth, the
isothermal surfaces are brought into equilibrium with the
new form of the soil. The lateral radiation from strata
which lie in the same level, but are differently covered,
44 I differ here from the opinion of one of my best friends, a physi-
cist \vhohas done excellent Rervice as regards the distribution of telluric
heat. See " upon the cause of the hot springs of Leuck and Warm-
brunn," Bischof, Lehrbuch der chtfMMchcn und physikalisclien
Bd. i, s. 127—133.

o 2

196 COSMOS.

plays in this case a more important part -than the direction
(inclination) of the cleavage planes of the rock, in cases
where stratification is observable.

I have already elsewhere mentioned45 how the hot springs
in the environs of ancient Carthage, probably the thermal
springs of Pertusa (aquce calidce of Hammam-el Enf ) led
Bishop Patricius, the martyr, to the correct view of the
cause of the higher or lower temperature of the bubbling
waters. When the Proconsul Julius tried to confuse the
accused Bishop by the mocking question, " Quo auctorefer-
vens hfpc aqua tantum ebulliat ? " Patricius set forth his
theory of the central heat, " which causes the fiery eruptions
of Etna arid Vesuvius, and communicates more and more
heat to the springs, in proportion as they have a deeper
origin." With the learned Bishop, Plato's Pyriphlegethon
was the hell of sinners ; and a,s though he desired at the

45 With regard to this passage, discovered by Bureau de la Malle,
see Cosmos, vol. i, pp, 220, 221. " Est autem," says Saint Patricius,
" et supra firmamentum cteli, et subter terrain ignis atque aqua ;
et quce supra terram est aqua, coacta in unum, appellationem ma-
rium : quse vero infra, abyssorum suscepit ; ex qiiibus ad generis
human! usus in terram velut siphones quidam emittuntur et scatu-
riunt. Ex iisdem quoque et thermae ex.sistunt : quarum quge ab igne
absunt longius, provida boni Dei erga nos mente, fnyidiores ; quce
vero propius admodum, ferventes fluunt. In quibusdam etiam locis et
tepidse aqua? reperiuntur, pro ut majore ab igue intervallo sunt dis-
junctac." So run the words in the collection : — Acta Primorum Mar-
tyrum, opera et studio T/teodorici Ruinart, ed. 2, Amstelaedami, 1713 fol.
p. 555. According to another report (A. S. Mazochii, in veins marmo-
reuin sanctce Neapolitans Ecclesice Kalendarium commentaries, vol. ii,
Neap. 1744, 4to, p. 385), Saint Patricius developed nearly the same
theory of telluric heat before the proconsul Julius, but at the conclu-
sion of his speech the cold hell is more distinctly indicated :— - " Nam
quse longius ab igne subterraneo absunt, Dei optimi providentia frigi-
diores erumpunt. At quD3 propiores igni sunt, ab eo fervefactse, into-
lerabili calore procditae promuntur foras. Sunt et alicubi tepidse,
quippe non parum sed longiuscule ab eo igne remotre. Atque ille in-
fernus ignis impiarum est animarum carnin'cina ; non secus ac subter-
raneus frigidissirnus gurges, in glaciei glebas concretus, qui Tartarus
nuncupatur." The Arabic name, Hamm&m-el-Enf, signifies nose-baths,
and is, as Temple has already remarked, derived from the form of a
neighbouring promontory, and not from a favourable action exerted by
this thermal water upon diseases of the nose. The Arabic nam- has
been variously altered by reporters: — Haminam 1'Enf or Lif, Eruma-
melif (Peyssonel), la Mamelif (Desfontaines). See Cumprecht, Die Mine'
ralqudlen auf dem FestlamJe von Africa (1851), s. 140 — 144.

THERMAL SPRINGS. 197

same time to remind one of the cold hells of the Buddhists,
an aqua gelidissima concrescens in glaciem is admitted,
somewhat unphysically and notwithstanding the depth, for
the nunquam jhiiendum siipplicium impiorum.

Amongst hot springs, those which, approaching the boil-
ing heat of water, attain a temperature of 194°F., are far more
rare than is usually supposed in consequence of inexact ob-
servations ; least of all do they occur in the vicinity of still
active volcanoes. I was so fortunate, during my American
travels, as to investigate two of the most important of these
springs, both between the tropics. In Mexico, not far from
the rich silver mines of Guanaxuato, in 21° N. lat., and at an
elevation of about 6500 feet above the surface of the sea;
near Chichermquillo.46 the Aquas de Comangillas burst forth
from a mountain of basalt and basaltic breccia. In Septem-
ber, 1803, 1 found their temperature to be 205°.5 F. This mass
of basalt has broken in the form of veins through a columnar
porphyry, which again rests upon a white syenite rich in
quartz. At a greater elevation, but not far from this nearly
boiling spring, near los Jbares, to the north of Santa Rosa
de la Sierra, snow falls from December to April even at an
elevation of 8,700 feet, and the inhabitants prepare ice the
whole year round, by radiation in artificial basins. On the
road from Nueva Valencia in the Valles de Aragua, towards
the harbour of Portocabello (in about 10i° of latitude),
on the northern slope of the coast chain of Venezuela, I saw
the aquas calientes de las Trincheras springing from a strati-
fied granite, which does not pass at all into gneiss. I found47
the springs in February, 1800, at 194°.5 F., whilst the
Banos de Mariara in the Valles de Aragua,, which belong to
the gneiss, showed a temperature of 138°.7 F. Twenty-
three years later, and again in the month of February, Bous-
singault and Rivero*8 found in the Mariara exactly 147°.2 F. ;

46 Humboldt, Essai Politique sur la Nouvelle Espayne, ed. 2, t. iii
(1827), p. 190.

4? Relation Historique, t. ii, p. 98; Cosmos, vol. i, p. 219. The hot
springs of Carlsbad also originate in the granite (Leop. von Buch, in
Poggend. Annalen, Bd. xii, s. 230), just like the hot springs of Momay,
in Thibet, visited by Joseph Hooker, which break forth near Chan-
grokhang, at an elevation of 16,000 feet above the sea, with a temper-
ature of 115° (Himalayan Journal, vol. ii, p. 133).

4' Boussingault, " Considerations sur les ea".x thermales des Cordfi

198 COSMOS.

and in the Trinoheras de Portocabello, at a small eleva-
tion above the Caribbean Sea, in one basin 198° F., in the
other 206°. 6 F. The temperature of these hot springs had
therefore risen unequally in the short interval between these
two periods : — in Mariara about 8°. 5 F., and in the Trincheras
about 12° 1 F. Boussingault has justly called attention to
ti e fact, that it was in the above mentioned interval that the
fearful earthquake took place, which overwhelmed the city
of Caraccas on the 26th of March, 1812. The commotion at
the surface was indeed not so strong in the vicinity of the
lake of Tacarigua (Nueva Valencia) ; but in the interior of
the earth, where elastic vapours act upon fissures, may not a
movement which propagated itself so far and so powerfully,
readily alter the net-work of fissures and open deeper canals
of supply ? The hot waters of the Trincheras, rising from a
granite formation, are nearly pure, as they only contain traces
of silicic acid, a little sulphuretted hydrogen and nitrogen ;
after forming numerous, very picturesque cascades, sur-
rounded by a luxuriant vegetation, they constitute a river,
the Rio de Aguas calientes ; and this, towards the coast, is
full of large crocodiles, to which the warmth, already con-
siderably diminished, is very suitable. In the most northern
parts of India (30° 52' N. lat.), and also from granite, issues
the very hot well of Jumnotri which attains a temperature
of 194° F., and as it presents this high temperature at an ele-
vation of 10,850 feet almost reaches the boiling point pro-
per to this atmospheric pressure.49

Amongst the intermittent hot springs, the Icelandic boil-
ing fountains, and of these especially the Great Geysir and
Strokkr, have justly attained the greatest celebrity. Ac-
cording to the admirable recent investigations of Bunsen.
Sartorius von Waltershausen and Descloiseaux the tempe-
rature of the streams of water in both diminishes in a remark-
able manner from below upwards. The Geysir possesses a
truncated cone of 25 to 30 feet in height formed by hori-
zontal layers of silicious sinter. In this cone there lies a
shallow basin of 52 feet in diameter, in the centre of which

leres," in the Annales de Chimie et de Physique, t. Hi, 1833, pp. 188 —
190.

49 Captain Newbold, " On the Temperature of the Wells and Pavers
in India and Egypt" (Phil. Transact, for 1845, pt. i, p. 127).

THERMAL SPRINGS. 19D

the funnel of the boiling spring, one -third of its diameter, and
surrounded by perpendicular walls, goes down to a depth of
75 feet. The temperature of the water which constantly
fills the basin is 180°. At very regular intervals of one hour
and 20 or 30 minutes the thunder below proclaims the com-
mencement of the eruption. The jets of water, of 9 feet
in thickness, of which about three large ones follow one
another, attain a height of 100 and sometimes 1#0 feet.
The temperature of the water ascending in the funnel has
been found to be 2 60°. 6 at a depth of 72 feet a little while
before the eruption, during the eruption 255°.5, and imme-
diately after it 251°.6 ; at the surface of the basin it is only
183° — 185°. The Strokkr, which is also situated at the base
of the Bjarnafell, has a smaller mass of water than the
Geysir. The sinter margin of its basin is only a few inches
in height and breadth. The eruptions are more frequent
than in the Geysir, but do not announce themselves by sub-
terranean thunder. In the Strokkr the temperature during
the eruption is 235°— 239° at a depth of 42 feet, and almost
212° at the surface. -The eruptions of the intermittent boil-
ing springs, and the slight changes in the type of the pheno-
mena are perfectly independent of the eruptions of Hecla, and
were by no means disturbed by the latter in the years 1845
and 1846.50 With his peculiar acuteness in observation and
discussion, Bun sen has refuted the earlier hypotheses regard-
ing the periodicity of the Geysir eruptions (subterranean
cauldrons, which, as steam-boilers, are filled sometimes with
vapours and sometimes with water). According to him the
eruptions are caused by a port ion of the column of water which

50 Sartorius von Waltersbausen, PhysiscTi-geographische STcizze von
Island, mit besonderer Riicksicht auf vullcanische Erscheinungen, 1847,
s. 128 — 132 ; Bunsen and Descloiseaux, in the Comptes rendus des
Seances de VAcad. des Sciences, t. xxiii, 1846, p. 935 ; Bunsen, in the
Annalen der Chemie und Pharmacie, Bd. Ixii, 1847, s. 27 — 45. Lottiu
and Robert had already found that the temperature of the jet of water
in the Geysir diminishes from below upwards. Amongst the forty sili-
cious bubbling springs, which are situated in the vicinity of the Great
Geysir and Strokkr, one bears the name of the Little Geysir. Its jet
of water only rises 20 or 30 feet. The term boiling springs (Koch-
brunnen) is derived from the word Geysir, which is connected with the
Icelandic giosa (to boil). On the high land of Thibet also, according to
the report of Esoma de Koros, there is, nenr the Alpine lake Mapham
a Geysir, which rises to the height of 12 feet.

200 COSMOS.

has acquired a high temperature at a lower point under great
pressure of accumulated vapours, being forced upwards, and
thus coming under a pressure which does not correspond
with its temperature. In this way " the Geysirs are natural
collectors of steam power."

Of the hot springs a few approach nearly to absolute
purity • others contain solutions of 8 — 12 parts of solid or
gaseous matters. Among the former are the baths of Lux-
eueil, Pfeffer, and Gastein, the efficacy of which may appear
so mysterious on account of their purity.81 As all springs
are fed principally by meteoric water, they contain nitrogen,
as Boussingault has proved in the very pure82 springs flowing
from the granite in las Trincheras de Portocabello, and Bun-
sen63 in the Cornelius spring at Aix and in the Geysir of
Iceland. The organic matter dissolved in many springs also
contains nitrogen, and is even sometimes bituminous. Until
it was known from the experiments of Gay-Lussac and my-
self that rain and snow-water contain more oxygen than
the atmosphere (the former 10, and the latter at least 8 per
cent, more) it appeared very remarkable that a gaseous mix-
ture, rich in oxygen, could be evolved from, the springs of
Nocera in the Apennines. The analyses made by Gay-Lus-
sac during our stay at this mountain spring showed that it
only contained as much oxygen as might have been furnished
to it by atmospheric moisture.54 If we be astonished at the

51 Trommsdorf finds in the springs of Gastein only 0.303 of solid
constituents in 1000 parts; Lowig, 0.291 in Pfeffer; and Longchamp
only 0.236 in Luxeuil; on the other hand, 0.478 were found in 1000
parts of common well water in Berne ; 5.459 in the Carlsbad bubbling
spring; and even 7.454 in Wiesbaden (Studer, P/iysikal. Geographic und
Geologic, ed. 2, 1847, cap. i, s. 92).

52 « The hot springs which gush from the granite of the Cordillera of
the coast (of Venezuela), are nearly pure ; they only contain a small
quantity of silica in solution, and hydrosulphuric acid gas, mixed with
a little nitrogen. Their composition is identical with that which would
result from the action of water upon sulphuret of silicium" (Annales de
Chimieet de Physique, t. lii, 1833, p. 189). Upon the great quantity
of nitrogen which is contained in the hot spring of Orense (154°.4),
see Maria Eubio, Tratado de las Fuentes Minerales de Espaiia, 1853,
p. 331.

53 Sartorius von Waltershausen, Skizze von Island, s. 125.

54 The distinguished chemist Morechini of Rome, had stated the
oxygen contained in the spring of Nocera (situated 2240 feet above the
snati to be 0.43 j Gay-Lnssac (26 September, 1805) found the exact

THERMAL SPBINGS. 201

Bilicious deposits as a constructive material of which nature,
as it were, artificially composes the apparatus of Geysirs, we
must remember that silicic acid is also diffused in many colci
springs which contain a very small portion of carbonic acid.

Acid springs and jets of carbonic acid gas, which were
long ascribed to deposits of coal and lignite, appear rather to
belong entirely to the processes of deep volcanic activity : —
an activity which is universally disseminated, and therefore
does not exert itself merely in those places where volcanic
rocks testify to the existence of ancient local fiery eruptions.
In extinguished volcanoes jets of carbonic acid certainly re-
main longest after the Plutonic catastrophes ; they follow
the stage of Solfatara activity ; but nevertheless waters im-
pregnated with carbonic acid, and of the most various tem-
peratures, burst forth from granite, gneiss, and old and new
fioetz mountains. Acid springs become impregnated with
alkaline carbonates, and especially with carbonate of soda,
wherever water impregnated with carbonic acid acts upon
rocks containing alkaline silicates.55 In the north of Ger-
many many of the carbonic acid springs and gaseous jets are
particularly remarkable for the dislocation of the strata
about them and for their eruption in circular valleys (Pyr-
mont, Driburg) which are usually completely closed. Fried-
rich Hoffman and Buckland have almost at the same time
very characteristically denominated such depressions valleys
of elevation ( Erhebu-ngs-Thaler).

In the springs to which the name of sulphurous waters is
given, the sulphur by no means constantly occurs combined
in the same way. In many, which contain no carbonate of
soda, sulphuretted hydrogen is probably dissolved ; in others,
for example in the sulphurous waters of Aix (the Kaiser,
Cornelius, Rose, and Quirinus springs), no sulphuretted
hydrogen is contained, according to the precise experiments
of Bunsen and Liebig, in the gases obtained by boiling the

quantity of oxygen to be only 0.299. We had previously found 0.31
of oxygen in meteoric waters (rain). Upon the nitrogen gas con-
tained in the acid springs of Neris and Bourbon 1'Archambault, seethe
works of Anglade and Longchatnp(lS34), and on carbonic acid exhala-
tions in general, see Bischof's admirable investigations in his Ckemiscfte
Geologic, Bd. i, s. 243—350.

55 Bunsen, in PoggendorfFs Annalen, Bd. Ixxxiii, s. 257; Bischof,
Geologic, Bd. i, s. 271.

202 COSMOS.

waters without access of air ; indeed the Kaiserquelle alonfl
contains 0.31 per cent, of sulphuretted hydrogen in gas
bubbles which rise spontaneously from the springs.56

A thermal spring which gives rise to an entire river of
water acidified by sulphur, the Vinegar river (Rio Vinagre),
called Pusambio by the aborigines, is a remarkable pheno-
menon to which I first called attention. The Rio Vinagre
rises at an elevation of about 10,660 feet on the north-
western declivity of the volcano of Purace, at the foot of which
the city of Popayan is situated. It forms three picturesque
cascades.57 of one of which I have given a representation,
falling over a steep trachytic wall probably 3.20 feet in per-

Eendicular height. From the point where the small river
Jls into the Cauca, this great river for a distance of 2 — 3
miles (from 8 to 12 English miles) downwards, as far as the
junctions of the Pindamon and Palace, contains no fish ;
which must be a great inconvenience to the inhabitants of
Popayan, who are strict observers of fasts ! According to
Boussingault's subsequent analysis, the waters of the Pusam-
bio contain a great quantity of sulphuretted hydrogen and
carbonic ac.d, with some sulphate of soda. Near the source,
Boussingault found the temperature to be 163°. The upper
part of the Pusambio runs underground. Degenhardt (of
Clausthal in the Harz), whose early death has caused a
great loss to Geognosy, discovered a hot spring in 1846 in
the Paramo de RVJ'Z, on the declivity of the volcano of the
same name, at the sources of the Rio Guali, and at an alti-
tude of 12,150 feet, in the water of which Boussingault
found three times as much sulphuric acid as in the Rio
Vinagre.

The equability of the temperature and chemical constitu-

56 Liebig and Bunseu, Untersuchung der Aachener Scheivefelquetten, in
the Annalen der Ckemie und Pharmacie, Bd. Ixxix (1851), s. 101. In
the chemical analyses of mineral waters which contain sulphuret of
sodium, carbonate of soda and sulphuretted hydrogen are often stated
to occur from an excess of cai-bonic acid being present in those waters.

5~ One of these cascades is represented in my Vues des Cordilleres,
pi. xxx. On the analysis of the water of the Eio Vinagre, see Boussin-
gault. in the .Annales de Ckimie et de Physique, 2e, s6rie, t. lii, 1833,
p. 397. and Dumas., 3e serie, t. xviii, 1846, p. 503; on the spring in the
Paramo do Ruiz, see Joaquin Acosba, Viajes Cientificos d los Andet
Ecuatoriales, 1849, p. 89.

THERMAL SPRINGS. 203

tion of springs as far as we can ascertain from reliable ob-
servations, is for more remarkable thaD the instability58
which has been occasionally detected. The hot spring-waters,
which, during their long and tortuous course, take up such a
variety of constituents from the rocks with which they are
in contact, and often carry them to places where they are
deficient in the strata through which the springs burst forth,
have also an action of a totally different nature. They exert
a transforming and at the same time a formative activity,
and in this respect they are of great geognostic importance.
Senarmont has shown with wonderful acuteness, how ex-
tremely probable it is that many vein-crevices (ancient courses
of thermal waters) have been filled from below upwards by

58 The examples of alteration of temperature in the thermal springs
of Mariara and las Trincheras lead to the question whether the Styx
water, whose source, so difficult of access, is situated in the wild
Aroanie Alps of Arcadia, near Nonacris, in the district of Pheneos, has
lost its pernicious qualities by alteration in the subterranean fissures of
supply ? or whether the waters of the Styx have only occasionally been
injurious to the wanderer by their icy coldness ? Perhaps they are
indebted for their evil reputation, which has been transmitted to the
present inhabitants of Arcadia, only to the awful wildness and desola-
tion of the neighboxarhood, and to the myth of their origin from Tar-
tarus. A young and learned philologist, Theodor Schwab, succeeded a
few years ago, with great exertion, in penetrating to the rocky wall
from which the spring trickles down, exactly as described by Homer,
Hesiod, and Herodotus. He drank some of the water, which was ex-
tremely cold, but very pure to the taste, without perceiving any injuri-
ous effects (Schwab, ArTcadien, seine Natur und Geschickte, 1852, s. 15 —
20). Amongst the ancients it was asserted that the coldness of the
water of the Styx burst all vessels except those made of the hoof of an
ass. The legends of the Styx are certainly very old, but the report of the
poisonous properties of its spring appears to have been widely dissemi-
nated only in the time of Aristotle. According to a statement of
Antigonus of Carystus (IIi»t. M'nab. § 174), it was contained very cir-
cumstantially iu a book of Theophrastus, which has been lost to us.
The calumnious fable of the poisoning of Alexander by the water of
the Styx, which Aristotle communicated to Cassander by Antipater, was
contradicted by Plutarch and Arriau, and disseminated by Vitruvius,
Justin, and Quintus Curtius, but without mentioning the Stagirite
(Stahr, Aristotelia, Th. i, 1830, s. 137 — 140). Pliny (xxx, 53) says,
somewhat ambiguously : — " Magna Aristotelia infamia excogitatum."
See Ernst Curtius, Pelvponnesiis (1851), Bd. i, s. 194 — 196, and 212;
St. Croix, Exainen Critique des Anciens Historiens d'Alejrandre, p. 496.
A representation of the cascade of the Styx, drawn from a distance, ia
contained in Fiedler's Reise durck Griechenland, Th. i,s. 400.

204 COSMOS.

the deposition of the dissolved elements. By changes of pres-
sure and temperature, by internal electro-chemical processes,
and the specific attraction of the lateral walls (the rock tra-
versed), sometimes lamellar deposits, and sometimes masses
of concretion are produced in fissures and vesicular cavities.
In this way druses and porous amygdaloids appear to have
been sometimes formed. Where the deposition of the veins
has taken place in parallel zones, these zones usually
correspond with each other symmetrically in their nature
both vertically and laterally. Senarmont has succeeded in
preparing a considerable number of minerals artificially, by
perfectly analogous synthetical methods.69

One of my intimate friends, a highly endowed scientific
observer, will, I hope, before long publish a new and impor-
tant work upon the conditions of temperature of springs, and
in it treat with great acumen and universality, by induction
from a long series of recent observations, upon the involved
phenomenon of disturbances. In the determinations of tem-
perature made by him in Germany (on the Rhine) and in Italy
(in the vicinity of Rome, in the Albanian mountains and
the Apennines) from the year 1845 to 1853, Eduard Hall-

59 « Very important metalliferous lodes, perhaps the greater number,
appear to have been formed by solution, while the veins filled witn
concretions of metal seem to be nothing but immense canals more or
less obstructed, and formerly traversed by encrusting thermal waters.
The formation of a great number of minerals which, are met with in
these lodes, does not always presuppose conditions or agents very far
removed from existing causes. The two principal elements of the most
widely diffused thermal waters, the alkaline sulphurets and carbonates,
have enabled me to reproduce artificially, by very simple synthetic
methods, 29 distinct mineral species, nearly all crystallised, belonging
to the native metals (native silver, copper, and arsenic), quartz, specular
iron, carbonates of iron, nickel, zinc, manganese, sulphate of baryta,
pyrites, malachite, copper pyrites, sulphuretof copper, red arsenical and
antimonial silver. . . . We approach as closely as possible to the pro-
cesses of nature, if we succeed in reproducing mineral? in their conditions
of possible association, by means of the most widely diffused natural
chemical agents, and by imitating the phenomena which we still see
realised in the foci in which the mineral creation has concentrated the
remains of that activity which it formerly displayed with a very dif-
ferent energy" (H. de Senarmont, Sur la Formation des Mineraux pa,'.'
la Voie Humide, in the Annales de Chemie et de Physique, 3eme sdrie
t. xxxii, 1851, p. 234 ; see also Elie de Beaumont, Sur les Emanations
Volcaniques e\ Metalliferes, in the bulletin de la Societe Geologique dt
France, 2e &e"rie, t. xv. p. 129).

THERMAL SPRINGS. 205

mann distinguishes : — 1. Purely meteorological springs, the
average temperature of which is not increased by the internal
heat of the earth ; 2. Meteorologico-geological springs, which,
being independent of the distribution of rain, and warmer
than the air, only undergo such alterations of temperature as
are communicated to them by the soil through which they
flow out ; 3. Abnormally cold springs, which bring down
their coldness from great elevations.80 The more we have

60 " In order to ascertain the amount of variation of the average tem-
perature of springs from that of the air, Dr. Ecluard Hallmann observed
at his former residence, Marienberg, near Boppard, on the Rhine, the
temperature of the air, the amount of rain and the temperature of seven
springs for five years, from the 1st December, 1845, to the 30th No-
vember, 1850 ; upon these observations he has founded a new elabora-
tion of the relative temperature of springs. In this investigation the
springs with a perfectly constant temperature (the purely geological
springs) are excluded. On the other hand, all those springs have been
made the subject of investigation which undergo an alteration in their
temperature according to the seasons.

" The variable springs fall into two natural groups : —

" 1. Purely meteorological springs : that is to say, those whose ave-
rage is demonstrably not elevated by the heat of the earth. In these
springs the amount of variation of the average from the aerial average is
dependent upon the distribution of the animal amount of rain through
the 12 months. These springs are on the average colder than the air
when the proportion of rain for the four cold months, from December
to March, amounts to more than 33^ per cent.; they are on the average
warmer than the air, when the proportion of rain for the four warm
months, from July to October, amounts to more than 33£ per cent.
The negative or positive difference of the spring-average from the air-
average, is larger in proportion to the excess of rain in the above-men-
tioned cold or warm thirds of the year. Those springs in which the
difference of the average from that of the air is in accordance with
the law, that is to say, the largest possible by reason of the distribution
of rain in the year, are called purely meteorological springs of undis-
torted average ; but those in which the amount of difference of the
average from the air average is diminished by the disturbing action of the
atmospheric heat during the seasons which are free from rain are called
purely meteorological springs of approximate average. The approxima-
tion of the average to the aerial average is caused either by the enclo-
sure, especially by a channel at the lower extremity of which the tem-
perature of the spring was observed, or it is the consequence of a super-
ficial course and the poverty of the feeders of the spring. In each year
the amount of difference of the average from the aerial average is
similar in all purely meteorological springs, but it is smaller in tho
approximate than in the undistorted springs, and indeed is smaller in
proportion as the disturbing action of the atmospheric heat is greater

206 COSMOS.

advanced of late years, by the successful employment of
chemistry, in the geognostic investigation of the formation

Of the springs of Marienberg 4 belong to the group of purely meteoro-
logical springs, of these 4 one is undistorted in its average, the three
others are approximated in various degrees. In the first year of obser-
vation the portion of rain of the cold third predominated, and all four
springs were on the average colder than the air. In the four following
years of observation the rain of the warm third predominated, and in
these all the four springs had <t higher average temperature than the
air; and the positive variation of. the average of the spring from that
of the air was higher, the greater the excess of rain in the warm third
of one of the four years. .

" The view put forward in the year 1825, by Leopold von Buch, that
the amount of variation of the average of springs from that of the air
must depend upon the distribution of rain in the seasons of the year
has been shown to be perfectly correct by Hallmann, at least for his
place of observation, Marienberg, in the Rhenish Grauwacke mountains.
The purely meteorological springs of undistorted average alone have
any value for scientific climatology ; these springs are to be sought for
everywhere, and to be distinguished on the one hand from the purely
meteorological springs with an approximate average, and on the other
from the rneteorologico-geological springs.

"2. Meteorologico-ge-jlogical springs: that is to s.ay, those of which
the average is demonstrably heightened by the heat of the earth. What-
ever the distribution of rain may be, these springs are in their average
warmer than the air, all the year round (the alterations of temperature
which they exhibit in the course of the year are communicated to them
by the soil through which they flow). The amount by which the
average of a rneteorologico-geological spring exceeds the atmospheric
average, depends upon the depth to which the meteoric waters have
sunk down into the interior of the earth, where the temperature is con-
stant, before they again make their appearance in the form of a spring ;
this amount consequently possesses no climatological interest. The
clirnatologist must, however, know these springs, in order that he may
not mistake them for purely meteorological springs. The meteorologico-
geological springs may also be approximated to the aerial average by an
enclosure or channel. The springs were observed on particular fixed
days, four or five times a month. The elevation above the sea, both of
the place where the temperature of the air was observed, and of the
different springs was carefully taken into account."

After the completion of the elaboration of his observations at Marien-
berg, Dr. Hallmann passed the winter of 1852 — 1853 in Italy, and
found abnormally cold springs in the vicinity of ordinary ones. This is
the name he gives "to those springs which demonstrably bring down
cold from above. These springs are to be regarded as subterranean
drains of open lakes or subterranean accumulations of water situated
at a great elevation, from which the waters pour down very rapidly
in fissures and clefts, and break forth *t the foot of the mountain or
chain of mountains in the form of springs. The idea of the abnormally

SALSES. 207

and metamorphic transformation of rocks, the greater im-
portance has been acquired for the consideration of the
waters impregnated with gases and salts which circulate in the
interior of the earth, and which, when they burst forth at the
surface as thermal springs, have already fulfilled the greater
part of their formative, alterative, or destructive activity.

c. Vapour and Gas Springs, Salses, Mud-volcanoes,
Naphtha-fire.

(Amplification of the Picture of Nature. Cosmos,
vol. i. pp. 221—223).

In the General Representation of Nature, I have shown by
well ascertained examples, which, however, have not been
sufficiently taken into consideration, how the salses in the
various stages through which they pass, from the first erup-
tions accompanied by flames, to the subsequent condition of
simple eruptions of mud, form as it were an intermediate
step between hot springs and true volcanoes, which throw
out fused earths, either in the form of disconnected cinders,
or as newly formed rocks, often arranged in many beds one
over the other. Like all transitions and intermediate steps
both in organic and inorganic nature, the salses and mud-
volcanoes deserve a more careful consideration than was
bestowed upon them by the older geognosists, from the want
of special knowledge of the facts.

The salses and naphtha springs are sometimes arranged in
isolated close groups : like the Macalubi, near Girgenti, in
Sicily, which were mentioned even by Solinus, those nearPietra
Mala, Barigazzo, and on the Monte Zibio, not far from Sas-
suolo in the north of Italy, or those near Turbaco in South
America ; sometimes they appear to be arranged in narrow
chains, and these are the most instructive and important.

cold springs is, therefore, as follows : — They are too cold for the eleva-
tion at which they come forth ; or, which indicates the conditions better,
they come forth at too low a part of the mountain for their low tem-
perature." These views, which are developed in the first volume of
Hallmann's Temperaturvcrhaltnissen der Quellen, have been modified by
the author in his second volume (s. 181 — 183), because in every
meteorological spring, however superficial it may be there must bo
some telluric heat.

COSMOS.

We have long known 61 as the outermost members of the
Caucasus, in the north-west the mud-volcanoes of Taman,

61 Humboldt, Asie Centrale, t. ii, p. 58. Upon the reasons which
render it probable that the Caucasus, which for ft.hs of its length, be-
tween the Kasbegk and lilburuz, runs from E.S.E. to W.N.W. in the
mean parallel of 42° 50', is the continuation of the volcanic fissure of
the Asferah (Aktagh) and Thian-schan, see the work cited above, pp. 54
— 61. Both the Asferah and Thian-schau oscillate between the parallels
of 40f° and 43°. I regard the great Aralo-Caspian depression, the sur-
face of which, according to the accurate measurements of Slruve,
exceeds the area of the whole of France by nearly 107,520 geographical
square miles (Op. cit. supra, pp. 309 — 312), as more ancient than the
elevations of the Altai and Thian-schan. The fissure of elevation of
the last-mentioned mountain chain has not been continued through the
great depression. It is only to the west of the Caspian Sea that we again
meet with it, with some alteration in its direction, as the chain of the
Caucasus, but associated with trachytic and volcanic phenomena. This
geognostic connection has also been recognised by Abich, and confirmed
by valuable observations. In a treatise on the connection of the Thian-
schan with the Caucasus by this great geognosist, which is in my pos-
session, he says expressly : — " The frequency and decided predominance
of a system of parallel dislocations and lines of elevation (nearly from
east to west) distributed over the whole district (between the Black Sea
and the Caspian) brings the mean axial direction of the great latitu-
dinal central Asiatic mass-elevations, most distinctly westward from the
Kosyurt and Bolar system* to the Caucasian Isthmus. The mean
direction of the Caucasus, S.E. — N.W., is E.S.E. — W.N.W. in the cen-
tral parts of the mountain chain, and sometimes even exactly E. — W., as
in the Thian-schan. The lines of elevation which unite Ararat with the
trachytic mountains Dzerlydagh and Kargabassar near Erzeroum, and in
the southern parallels of which Mount Argaeus, Sepandagh, and Sabalan
are arranged, constitute the most decided expression of a mean volcanic
axial direction, that is to say, of the Thian-schau being prolonged west-
ward through the Caucasus. Many other mountain-directions of
Central Asia, however, also revert to this remarkable space, and stand,
as elsewhere, in mutual relation to each other, so as to form vast moun-
tain nuclei and maxima of elevation." Pliny (vi, 17), says : — " Persse
appellavere Caucasum montem Graucasim (var. Graucasum, Groucasim,
Grocasurn), hoc est nive candidum ;" in which Bohleu thought the
Sanscrit words Teds, to shine, and gravan, rock, were to be recognised
(see my Asie Centrale, t. i, p. 109). As Klausen says, in his investiga-
tions on the wanderings of lo (Rheinisckes Museum fur Philoloyie,
Jahrg iii, 1845, s. 298), if the name Graucasus was corrupted into Cau-
casus, then a name " in which each of its first syllables gave the Greeks
the idea of burning might certainly characterise a burning mountain,
with which the history of the Fire-burner (Fire-igniter, -rrvoKatvi-) would
become readily and almost spontaneously associated." It cannot be denied
that myths sometimes originate from names, but the production of so
great and important a fable, as the Typhonico-caucasic, can certainly not

SALSES. 209

and in the south-east of the great mountain chain, the
naphtha-springs and naphtha-fire of Baku and the Caspian
peninsula, Apscheron. The magnitude and connection of
this phenomenon was, however, first discovered by Abich,
distinguished by his profound knowledge of this part of
Asia. According to him, the mud-volcanoes and naphtha-
fires of the Caucasus are arranged in a distinctly recognisable
manner in certain lines, which stand in unmistakeable rela-
tion with the axes of elevation and the directions of dislo-
cation of the strata of rock. The greatest space, of nearly
4,000 square miles, is occupied by genetically connected
mud-volcanoes, naphtha-emanations and saline springs in
the south-eastern part of the Caucacus, in an isosceles
triangle, the base of which is the shore of the Cas-

be derivable from the accidental similarity of sound in the misunderstood
name of a mountain. There are better arguments, of which Klausen also
mentions one. From the actual association of Typhon and the Caucasus,
and from the express testimony of Pherecydes of Syros (in the time of
the 58th Olympiad), it is clear that the eastern extremity of the world
was regarded as a volcanic mountain. According to one of the Scholia
to Apollonius (Scholia in Apoll. Rhod., ed. Schaeiferi, 1813, v. 1210,
p. 524), Pherecydes says, in the Theogony, "that Typhon, when pur-
sued, fled to the Caucasus, and that then the mountain burnt (or was
set on fire); that from thence Typhon fled to Italy, when the island
Pithecusa was thrown around (as it were, poured around) him." But
Pithecusa is the island ^Enaria (now Ischia), upon which the Epomeus
(Epopon) cast forth fire and lava, according to Julius Obsequens, 95
years before our era, then during the reigns of Titus and Diocletian,
and lastly, in the year 1302, according to the statement of Tolomeo
Fiadoni of Lucca, who was at that time Prior of Santa Maria Novella.
" It is singular," as Boeckh, the profound student of antiquity, writes to
me, " that Pherecydes should make Typhon fly from the Caucasus
because it burnt, as he himself is the originator of subterraneous fire;
but that his residence upon the Caucasus rests upon the occurrence of
volcanic eruptions there, appears to me to be undeniable." Apollonius
Rhodius (Argon, lib. ii, v. 1212 — 1217, ed. Beck) in speaking of the birth
of the Colchian Dragon, also places in the Caucasus the rock of Typhon,
on which the giant was struck by the lightning of Jupiter. Although the
lava-streams and crater-lakes of the high land of Kely, the eruptions of
Ararat and Elburuz, or the currents of obsidian and pumice-stone from
the old craters of the Puotandagh, may be placed in a pre-historic
period, still the many hundred flamos which even now break forth
from fissures in the Caucasus, both from mountains of seven or eight
thousand feet in height and from broad plains, may have been a suffi-
cient reason for regarding the entire, mountain district of the Caucasus
as a Typhonic seat of fire.

VOL. Y. P

210 COSMOS.

plan Sea near Balachani (to the north of Baku) and one of
the mouths of the Kur (Araxes), near the hot springs of
Sallian. The apex of such a triangle is situated near the
Schagdagh in the elevated valley of Kinalughi. There, at
the boundary of a, dolomitic and slate formation, at an ele-
vation of 8350 feet above the Caspian Sea, close to the
village of Kinalughi itself, break forth the perpetual fires of
the Schagdagh, which have never been extinguished by me-
teorological occurrences. The central axis of this triangle
corresponds with the direction which the earthquakes, so
often experienced in Schamacha upon the banks of the
Pyrsagat, appear constantly to follow. When the north-
western direction just indicated is traced further, it strikes
upon the hot sulphurous springs of Akti, and then becomes
the line of strike of the principal crest of the Caucasus where
It rises up into the Kasbegk and bounds Daghestan. The
salses of the lower region, which are often regularly arranged
in series, gradually become more numerous towards the shore
of the Caspian, between Sallian, the mouth of the Pyrsagat
(near the island of Swinoi), and the peninsula of Apscheron.
They present traces of repeated mud eruptions in earlier
times, and often bear at their summits small cones, from
which combustible and often spontaneously ignited gas is
poured forth, and which are exactly similar in form to the
hornitos of Jortillo in Mexico. Considerable eruptions of
flame were particularly frequent between 1844 and 1849, at
the Oudplidagh, Nahalath, and Turandagh. Close to the
mouth of the Pyrsagat on the mud volcano Toprachali,
" black marly fragments, which at the first glance might be
confounded with dense basalt, and extremely fine-grained
doleritic rocks" are found (a proof of the exceptional, greatly
increased intensity of the subterranean heat). At other
points on the peninsula of Apscheron, Lenz found slag-like
fragments as products of eruption ; and during the great
eruption of flame of Backlichli (7th February, 1839), small
hollow balls, like the so-called ashes of the true volcanoes,
were carried by the wind to a long distance.62

62 Humboldt, Asie Centrale, t. ii, pp. 511 and 513. I Lave already
(t. ii, p. 201 ) called attention to the fact that Edrisi does not mention
the fire of Baku, although it is described diffusely as a Nefala-land, that
is to say, rich in burning naphtha swings, by Mass1*^/ *)othbeddin, two

SALSES. 211

In the north-western extremity towards the Cimmerian
Bosphorus are the mud volcanoes of the peninsula of Taman,
which form, one group with those of Aklanisowka and
Jenikale near Kertsch. One of the salses of Taman exhibited
an eruption of mud and gas on the 27th of February, 1793, in
which, after much subterranean noise, a column of fire half
enveloped in black smoke (dense aqueous vapour ?) rose to a
height of several hundred feet. It is a remarkable pheno-
menon, and instructive as regards the nature of the Volcan-
citos de Turbaco, that the gas of Taman. which was tested in
1811 by Frederick Parrot and Engelhardt, was not inflam-
mable -j whilst the gas collected by G-obel in the same place,
23 years later, burnt, from the mouth of a glass tube, with
a bluish flame like all emanations from the salses in the
south-eastern Caucasus, but also, when carefully analysed,
contained in 100 parts 92.8 of carburetted hydrogen and 5
parts of carbonic oxide gas.63

A phenomenon certainly nearly allied to these in its origin,
although different as regards the matter produced, is pre-
sented by the eruptions of boracic acid vapours in the Tuscan
Maremma, known under the names of lagoni, fiimmarole,
soffioni, and even volcani, near Possara, Castel Novo, and
Monte Cerboli. The vapours have an average temperature
of 205° to 212°, and according to Pella, in certain points, as
much as 347°. They rise in part directly from clefts in the
rocks, and partly from stagnant pools, in which they throw up
small cones of fluid clay. They are seen to diffuse them-
selves in the air in whitish eddies. The boracic acid, which
is brought up by the aqueous vapours from the bosom of
the earth, cannot be obtained when the vapours of the
sqffioni are condensed in very wide and long tubes, but
becomes diffused in the atmosphere in consequence of its
volatility. The acid is only procured in the beautiful esta-
blishments of Count Larderel, when the orifices of the

hundred years before, in the tenth century (see Frahn, Ibn Fozlan,
p. 245, and on the etymology of the Median word naphtha, Asiatic
Journal, vol. xiii, p. 124).

6:5 Compare Moritz von Engelhardt and F. Parrot, Reise in die Krym
und den Kaukasus, 1815, Th. i, s. 71, with Gobel, Reise in die Steppen
dex xiid lichen Russlands, 1838, Th. i, s. 249—253. aud Th. ii, s. 138
—144,

p 2

212 COSMOS.

sofnoni are covered directly by the fluid of the basin.64
.According to Payen's excellent analysis, the gaseous emana-
tions contain 0'57 of carbonic acid, 0'35 of nitrogen, and
only 0'07 of oxygen, and O001 of sulphuric acid. Where
the boracic acid vapours permeate the clefts of the rock,
they deposit sulphur. According to Sir "Roderick Murchi-
son's investigations the rock is in part of a chalky nature,
and in part an eocene formation, containing nummulites — a
maciffno, which is penetrated by the uncovered and elevated
serpentine 65 ol the neighbourhood (near Monte Rotondo). In
this case, and in the crater of Volcano, asks Bischof, do
not hot aqueous vapours act upon and decompose boracic
minerals, such as rocks rich in datolithe, axinite or tourma-
line?66

In the variety and grandeur of the phenomena, the system
of somoni in Iceland exceeds anything that we are ac-
quainted with on the continent. Actual mud-springs burst
forth in the fumarole-field of Krisuvek and Reykjalidh,
from small basins with crater-like margins in a bluish gray

64 Payen, De I'acide boracique des Suffioni de la Toscane, in the
Annaks de Chimie et de Physique, 3me se"rie, t. i, 1841, pp. 247 — 255 ;
Bischof, Chem. imd Physik. Geologic, Bd. i, s. 669—691; EtaUissements
industriels de I'acide boracique en Toscane, by the Count de Larderel,
p. 8.

65 Sir Eoderick Impey Murchison, On the vents of hot vapour in Tus-
cany, 1850, p. 7 (see also tl'e earlier geognostic observations of Hoff-
mann, in Karstens und JJechens Archiv fur Mineral. Bd. xiii, 1839,
s. 19). From old but trustworthy traditions, Targioni Tozzeti asserts
that some of these boracic acid springs which are constantly changing
their place of eruption were once seen to be luminous (ignited) at night.
In order to increase the geological interest of the observations of Mur-
chison and Pareto upon the volcanic relations of the serpentine forma-
tion in Italy, I may here advert to the fact that the flame of the Asiatic
Chimcera (near the town of Deliktasch, the ancient Phaselis in Lycia,
on the west coast of the Gulf of Adalia) which has been burning lor
several thousand years, also rises from a hill on the slope of the Soli-
mandagh, in which serpentine in position and blocks of limestone have
been found, liather more to the south, on the small island of Gram-
busa, the limestone is deposited upon dark-coloured serpentine. See
the important work of Admiral Beaufort (Survey of the Coasts of Cara-
mania, 1818, pp. 40 and 48), whose statements are confirmed by the
specimens of rocks just brought home (May, 1854), by a highly talented
artist, Albrecht Berg (Pierre de Tchihatcheff, Asie Mineure, 1853, t. i,
p. 407.)

66 Bischof, op. cit. s. 682.

COSMOS. 213

clay.67 Here also the fissures of the springs may be traced
in determinate directions.68 There is no portion of the earth,
where hot springs, salses and gas-eruptions occur, that has
been made the subject of such admirable and complete che-
mical investigations as those on Iceland, which we owe to
the acute and persevering exertions of Bunsen. Nowhere,
perhaps, in such a great extent of country, or so near the
surface, is such a multifarious spectacle of chemical decom-
positions, conversions, and new formations to be witnessed.

Passing from Iceland to the neighbouring American con-
tinent we find in the State of New York, in the neighbour-
hood of Fredonia, not far from Lake Erie, a multitude of
jets of inflammable gas (carburetted hydrogen), breaking forth
from fissures in a basin of Devonian sandstone strata, and
partly employed for the purpose of illumination. Other
springs of inflammable gas, near Rushville, assume the form
of mud cones ; and others, in the valley of the Ohio, in
Virginia, and on the Kentucky river, also contain chloride
of sodium, and are there connected with weak naphtha
springs. But on the other side of the Caribbean Sea, on the
north coast of South America, 11^ miles south-south-east
from the harbour of Cartagena de Indias, near the plea-
sant village of Turbaco, a remarkable group of salses or
mud- volcanoes exhibits phenomena, which I was the first to
describe.

In the neighbourhood of Turbaco, where one enjoys a
magnificent view of the colossal snowy mountains (Sierras
Nevadas) of Santa Marta, on a desert spot in the midst of
the primeval forest, rise the Volcancitos, to the number of
18 or 20. The largest of the cones, which consist of blackish
gray loam, are from 19 to 23 feet in height, and probably
80 feet in diameter at the base. At the apex of each cone
is a circular orifice of 20 to 28 inches in diameter, surrounded
by a small mud-wall. The gas rushes up with great violence,
as in Taman, forming bubbles, each of which, according to
my measurements in graduated vessels, contains 10 — 12
cubic inches. The upper part of the funnel is filled with

67 Sartorius von "\Valtershausen, Plnjsiscli-geoyrapliixclie Sklz:.e von
Island, 1847, R. 123; Bunsen "upon the processes of formation of the
volcanic rocks of Iceland," Pog^end. Annalen, Bd. Ixxxiii, s. 207.

68 Waltershausen, op. cit. s. 11 £.

214 COSMOS.

water, which rests upon a compact floor of mud. The erup-
tions are not simultaneous in neighbouring cones, but in
each one a certain regularity was observable in the periods
of the eruptions. Bonpland and I, standing on the outer-
most parts of the group, counted pretty regularly 5 eruptions
every 2 minutes. On beading down over the small orifice
of the crater a hollow sound is perceived in the interior of
the earth, far below the base of the cone, usually 20 seconds
before each eruption. A very thin burning wax taper was
instantly extinguished in the gas, which was twice collected
with great care ; this was also the case with a glowing chip
of the wood Bombax Ceiba. The gas could not be ignited.
Lime water was not rendered turbid by it ; no absorption
took place. When tested for oxygen with nitrous acid gas,
this gas showed no trace of the former in one experiment ;
in a second case, when the gas of the Yolcancitos had been
confined for many hours in a bell glass with water, it exhi-
bited ratter more than one hundredth of oxygen, which
had probably been evolved from the water and accidentally
intermixed.

From these analytical results I then declared, perhaps not
very incorrectly, that the gas of the Volcancitos of Turbaco
was nitrogen gas, which might be mixed with a small
quantity of hydrogen. At the same time I expressed my
regret in my journal, that in the state of chemistry at that
time (April, 1801), no means were known by which, in a
mixture of nitrogen and hydrogen gases, the numerical
proportions of the mixture might be determined. The
expedient, by the employment of which three thousandths
of hydrogen may be detected in a gaseous mixture, was only
discovered by Gay-Lussac and myself four years afterwards,69
During the half-century that has elapsed since my residence
in Turbaco, and my astronomical survey of the Magdalena
river, no traveller had occupied himself scientifically with
the small mud-volcanoes just described, until, at the end of
December, 1850, my friend Joaquin Acosta,70 so well versed

69 Humboldt and Gay-Lussac, Memoire sur ^analyse de I'air atmo-
spherique in the Journal de Physique, par Lametherie, t. Ix, p. 151 (see
my Kleinere Schriften, Bd. i, s. 346).

70 " It is with emotion that I have just visited a place which you
made known fifty years ago. The appearance of the small volcanoes of

SALSES. 215

in modern geognosy and chemistry, made the remarkable
observation that at present " the cones diffuse a bituminous
odour ;" (of which no trace existed in my time) ; " that some
petroleum floats upon the surface of the water in the small
orifices, and that the gas pouring out may be ignited upon
every mud-cone of Turbaco." Does this, asks Acosta, indi-
cate an alteration of the phenomena brought about by
internal processes, or simply an error in the earlier experi-
ments ? I would admit the latter freely, if I had not
preserved the leaf of the journal on which the experiments
were recorded in detail,71 on the very morning on which

Turbaco is such as you have described ; there is the same luxuriance
of vegetation, the same form of cones of clay, and the same ejection 01
liquid and muddy matter ; nothing has changed, unless it be the
nature of the gas which is evolved. I had with me, in accordance
with the advice of our mutual friend, M. Boussiugault, all that was
necesssary for the chemical analysis of the gaseous emanations, and even
for making a freezing mixture for the purpose of condensing the aqueous
vapour, as the doubt had been expressed to me that nitrogen might
have been confounded with this vapour. But this apparatus was by
no means necessary. As soon as I arrived at the Volcancitos, the dis-
tinct odour of bitumen set me in the right course; I commenced by
lighting the gas upon the very orifice of each small crater. Even now
one sees on the surface of the liquid, which rises intermittently, a deli-
cate film of petroleum. The gas collected burns away entirely, without
any residue of nitrog-en(?) and without depositing sulphur (when in
contact with the atmosphere). Thus the nature of the phenomenon has
completely c/tanr/ed since your journey, unless we admit an error of obser-
vation, justified by the less advanced state of experimental chemistry
at that period. I no longer doubt that the great eruption of Galera
Zamba, which illuminated the country in a radius of 100 kilometres
(62 miles), is a salses-like phenomenon, developed on a great scale, since
there exist hundreds of little cones, vomiting saline clay, upon a surface
of 400 square leagues. I propose examining the gaseous products of
the cones of Tubara, which are the most distant salses from your
Volcancitos of Turbaco. From the powerful manifestations which have
caused the disappearance of a part of the peninsula of Galera Zamba,
now become an island, and from the appearance of a new island raised
from the bottom of the sea in 1848, and which has since disappeared,
I am led to think that it is near Galera Zamba, to the west of the delta
of the Rio Magdalena, that the principal focus of the phenomenon of
salses in the province of Carthagena is situated" (from a letter from
Colonel Acosta to A. von Huinboldt, Turbaco, 21 December, 1850).
See also Mosquera, Memoria politica sobre la Nueva Granada, 1852,
p. 73 ; and Lionel Gisborne, The Isthmus of Darien, p. 48.

71 During the whole of my American expedition I always adhered
strictly to the advice of Yauquelin, under whom I worked for some time

216 COSMOS.

they were made. I find nothing in them that could make
me at all doubtful now ; and the observation already referred

before my voyage : to write down and preserve the details of every
experiment on the same day. From my journals of the 17th and
18th April, 1801, I here copy the following : — " As, therefore, the gas
showed scarcely 0.01 of oxygen from experiments with phosphorus
and nitrous acid gas, and not 0.02 of carbonic acid with lime-water, the
question is, what are the other 97 hundredths? I supposed, first of all,
carburetted and sulphuretted hydrogen ; but no sul phur is deposited
on the margins of the small craters in contact with the atmosphere,
and no odour of sulphuretted hydrogen was to be perceived. The pro-
blematical part might appear to be pure nitrogen, for, as above men-
tioned, nothing was ignited by a burning taper ; but I know, from the
time of my analyses of fire-damp, that a light hydrogen gas, free from
any carbonic acid, which merely stood at the top of a gallery did not
ignite, but extinguished the pit candles, whilst the latter burnt clearly
in deep places, when the air was considerably mixed with nitrogen gas.
The residue of the gas of the Volcancitos is, therefore, probably to be
regarded as nitrogen, with a portion of hj'drogen gas, the quanti-
tative amount of which ,we do not at present know. Does the same
carbonaceous schist that I saw further westward on the Rio Sinu, or
marl and clay, lie below the Volcancitos ? Does atmospheric air penetrate
through narrow fissures into cavities formed by water and become de-
composed in contact with blackish gray loam, as in the pits in the
saline clay of Hallein and Berchtholdsgaden, where the chambers are
filled with gases which extinguish lights ? or do the gases, streaming out
tense and elastic, prevent the penetration of atmospheric air?" These
questions were sf't down by me in Turbaco 53 years ago. According to
the most recent observations of M. Vauvert de Mdan (1854) the inflam-
mability of the gas emitted has been completely retained. The traveller
brought with him samples of the water which fills the small orifice of
the craters of the Volcancitos. In this Boussingault found in the litre:
common salt, 6.59 gr. ; carbonate of soda, 0.31; sulphate of soda, 0.20;
and also traces of borate of soda and iodine. In the mud which had
fallen to the bottom, Ehrenberg, by a careful microscopic examination,
found no calcareous parts or scoriaceous matter, but quartz granules
mixed with micaceous laminre, and many small crystalline prisms of
black Augite, such as often occurs in volcanic tufa ; no trace of Spon-
giolites or Polygastric Infusoria, and nothing to indicate the vicinity
of the sea, but on the contrary many remains of Dicotyledonous plants
and grasses, and sporangia of lichens, reminding one of the consti-
tuents of the Moya of Pelileo. Whilst C. Saiute-Claire, Deville, and
George Bornemann, in their beautiful analyses of the Macalube di
Terrapilata, found 0.99 of carburetted hydrogen in the gas emitted, the
gas which rises in the Agua Santa di Limosina, near Catanea, gave
them, like Turbaco formerly, 0.98 of nitrogen, without a trace of.
oxygen (Comptes rendus de I'Acad. des Sciences, t. xliii, 1856, pp. 361
and 366).

SALSES. 217

to (from Parrot's Keports), that "the gas of the mud-
volcanoes of the peninsula of Taman in 1811 had the
property of preventing combustion, as a glowing chip was
extinguished in the gas, and even the ascending bubbles, a
foot in diameter, could not be ignited at the moment of
their bursting," whilst in 1834, Gobel saw readily inflam-
mable gas burning with a bluish flame at the same place, —
leads me to believe that the emanations undergo chemical
changes in different stages. Yery recently Mibscherlich has,
at my request, determined the limits of inflammability of
artificially prepared mixtures of nitrogen and hydrogen
gases. It appeared that mixtures of 1 part of hydrogen
gas and 3 parts of nitrogen gas, not only took fire from a
light, but also continued to burn. When the quantity of
nitrogen gas was increased, so that the mixture consisted oi
1 part of hydrogen and 3J parts of nitrogen, it was still
inflammable, but did not continue burning. It was only
ivitk a mixture of\ part nf hydrogen and 4 parts of nitrogen
gas tliat no ignition too place. The gaseous emanations, which
from their ready inflammability and the colour of their
flame are usually called emanations of pure and carburetted
hydrogen, need therefore consist quantitatively only of one-
third part of one of the last-mentioned gases. With mix-
tures of carbonic acid and hydrogen, which occur more
rarely, the limits of inflammability prove different again,
on account of the capacity for heat of the former. Acosta
justly suggests the question: — "Whether a tradition dis-
seminated amongst the inhabitants of Turbaco, descendants
of the Indios de Taruaco, according to which the Volcancitos
formerly all burnt; and were converted from Volcanes de
fucgo into Volcares de agua, by being exorcised and sprinkled
with holywater by a pious monk72, may not refer to a con-
dition which has now returned ?" Single great eruptions of
flames from mud volcanoes, which both before and since
have been very inactive (Tainan, 1793 ; on the Caspian
Sea, near Jokmali, 1827; and near Baklichli, 1839; near

72 Humboldt, Vues des Cordilleres et Monuments dcs pcuples indigenes
de I'Amerique, pi. xli, p. 239. The beautiful drawing of the Volcancitos
de Turbaco, from which the copperplate was engraved, was made by my
young fellow-traveller, Louis de Rieux. Upon the old Taruaco in the
first period of the Spanish Conquista, see Herrera, Dec. i, p. 251.

218 COSMOS.

Kuschtschy, 1846, also in the Caucasus), present analogous
examples.

The apparently unimportant phenomenon of the salses
of Turbaco, has gained in geological interest by the ter-
rible eruption of flame, and the terrestrial changes which
occurred in 1839, more than 32 geographical miles to the
N.N.E. of Cartagena de Indias, between this harbour and
that of Sabanilla, not far from the mouth of the great
Magdalena river. The true central point of the phenomenon
was the Cape Galera Zamba, which projects 6 — 8 geo-
graphical miles into the sea, in the form of a narrow penin-
sula. For the knowledge of this phenomenon we are also
indebted to Colonel Acosta, of whom science has unfor-
tunately been deprived by an early death. In the
middle of the tongue of land there stood a conical hill,
from the crater of which smoke (vapours) and gases some-
times poured forth with such violence that boards and
large pieces of wood which were thrown into it were cast
back again to a great distance. In the year 1839 the
cone disappeared during a considenible eruption of fire, and
the entire peninsula of Galera Zamba became an island,
separated from the continent by a channel of 30 feet in
depth. The surface of the sea continued in this peaceful
state until on the 7th of October, 1848, at the place of
the previous breach, a second terrible eruption of flames 73
appeared, without any perceptible earthquake in the
vicinity, lasted for several days, and was visible at a
distance of from 40 to 50 miles. The salse only emitted gases,
but no solid matters. When the flames had disappeared
the sea-bottom was found to be raised into a small
sandy islet, which however soon disappeared again. More
than 50 volcancitos (cones similar to those of Turbaco)
now surround the submarine gas volcano of Galera Zamba,
to a distance of from 18 to '23 miles. In a geological point of
view we may certainly regard this as the principal seat of
the volcanic activity which strives to place itself in contact
with the atmosphere, over the whole of the low country
from Turbaco to beyond the delta of the Bio Grande de la
Magdalena.

73 Lettre de M. Joaquin Acosta k M. Elie de Beaumont, in the
Comptes rendus de VAcad. des Sciences, t. xxix, 1849, pp. 530 — 534.

SALSES. 219

The uniformity of the phenomena which are presented in
the various stages of their activity, by the salses, mud vol-
canoes, and gas-springs on the Italian peninsula, in the
Caucasus and in South America, is manifested in enormous
tracts of land in the Chinese empire. The art of man has
there from the most ancient periods known how to make use
of this treasure ; nay, even led to the ingenious discovery of
the Chinese rope-boring, which has only of late become
known to Europeans. Borings of several thousand feet in
depth are produced by the most simple application of human
strength, or rather of the weight of man. I have elsewhere 74
treated in detail of this discovery, and also of the " fire
springs," Ho-tsing, and "fiery mountains," Ho-schan, of
Eastern Asia. They bore for water, brine-springs, and in-
flammable gas, from the south-western provinces, Yun-nan,
Kuang-si, and Szu-tschuan on the borders of Thibet, to the
northern province Schan-si. When it has a reddish flame,
the gas often diffuses a bituminous odour ; it is transferred
partly in portable and partly in lying bamboo-tubes to re-
mote places, for use in salt-boiling, for heating the houses, or
for lighting the streets. In some rare cases supply of
carburetted hydrogen gas has been suddenly exhausted, or
stopped by earthquakes. Thus we know that a celebrated
Ho-tsing, situated to the south-west of the town of Khiung-
tscheu (latitude 50° 27,' longitude 101° 6' East), which was
a salt spring burning with noise, was extinguished in the
thirteenth century, after it had illuminated the neighbour-
hood from the second century of our era. In the province
of Schan-si, which is so rich in coal, there are some ignited
carbonaceous strata. Fiery mountains ( Ho-schan) are distri
buted over a great part of China. The flames often rise to a
great height, for example, in the mass of rock of the Py-kia-

<"4 Humboldt, Asie Centrale, t. ii, pp. 519 — 540; principally from
extracts from Chinese works by Klaproth and Stanislas Julien. The old
Chinese rope-boring, which was repeatedly employed, and sometimes
with advantage, in coal-pits in Belgium and Germany between 1830 and
1842, had been described (as Jobard has discovered) as early as the
17th century, in the Relation of the Dutch Ambassador, Van Hoorn,
but the most exact account of this method of boring the fire-springs
(Ho-tsing) is given by the French missionary, Imbert, who resided so
many years in Kia-ting-fu (see Annales de la, Propagation de la Foy,
1829, pp. 369—381).

220 COSMOS.

schan, at the foot of a mountain covered with perpetual snow
(lat. 31° 40'), from long, open, inaccessible fissures : a pheno-
menon which reminds us of the perpetual fire of the Shag-
dagh mountain in the Caucasus.

On the Inland of Java, in the province of Samarang,
at a distance of about fourteen miles from the north coast,
there are salses similar to those of Turbaco and Galera
Zamba. Very variable hills of 25 to 30 feet in height,
throw out mud, salt-water, and a singular mixture of
hydrogen gas and carbonic-acid76; a phenomenon which is
not to be confounded with the vast and destructive streams
of mud which are poured forth during the rare eruptions of
the true, colossal volcanoes of Java (Gununq Kelut and
Gunung Idjen). Some mofette-grottoes or sources of car-
bonic acid in Java are also very celebrated, particularly in
consequence of exaggerations in the statements of some
travellers, as also from their connexion with the myth of the
Upas poison-tree, already mentioned by Sykes and Loudon.
The most remarkable of the six has been scientifically de-
scribed by Junghuhn, the so-called Vale of death of the
island (PaJcaraman) in the mountain Dieng, near Batur.
It is a funnel-shaped sinking on the declivity of a moun-
tain, a depression in which the stratum of carbonic acid
emitted attains a very different height at different seasons.
Skeletons of wild hogs, tigers, and birds are often found in
it.76 The poison-tree, pohon (or better puhn) upas of the
Malays (Antiaris toxicaria of the traveller Leschenault de

75 According to Diard, Asie Centrale, t. ii, p. 515. Besides the mud
volcanoes of Damak and Surabaya, there are upon other islands of the
Indian Archipelago the mud volcanoes of Pulu-Semao, Pulu-Kambing,
and Pulu-Koti : see Junghuhn, Java, seine Gestalt und Pflanzendeckc,
1852, Abth. iii, s. 830.

?6 Junghuhn, Op. cit., Abth. i, s. 201, and Abth. iii, s. 854—858.
The weaker suffocating caves on Java are Gua-Upas and Gua-Galan
(the first word is the Sanscrit, gnhd, cave). As there can certainly be
no doubt that the Grotto del Cane, in the vicinity of the Lago di Agnano
is the same that Pliny (ii, cap. 93) described nearly 18 centuries ago,
"in agro Puteolano," as "Charonea scrobis mortiferum spiritum
exhalans," we must certainly share in the surprise felt by Scacchi
(Memorie geol. sulla Campania, 1849, p. 48), that in a loose soil, so
often moved by earthquakes, so small a phenomenon (the supply of
a small quantity of carbonic acid) can have remained unaltered and un-
disturbed.

SALSES. 221

la Tour), with its harmless exhalations, has nothing to do
with these fatal actions.77

I conclude this section on the salses and steam and gas
springs, with the description of an eruption of hot sulphu-
rous vapours, which may attract the interest of geognosists
on account of the kind of rock from which they are evolved.
During my delightful, but somewhat fatiguing passage over
the central Cordillera of Quindiu, (it took me 14 or 15 days
on foot, and sleeping constantly in the open air, to get over
the mountain crest of 11.500 feet from the valley of the Rio
Magdalena into the Cauca valley), when at the height of
6810 feet I visited the Azufral to the west of the station el
Moral. In a mica-schist of a rather dark colour, which, re-
posing upon a gneiss containing garnets, surrounds, with the
latter, the elevated granite domes of la Ceja and la Garita
del Paramo, I saw hot sulphurous vapours flowing out from
the clefts of the rocks in a narrow valley (Quebrada del
Azufral). As they are mixed with sulphuretted hydrogen
gas and much carbonic acid, a stupefying dizziness is expe-
rienced on stooping down to measure the temperature, and
remaining long in their vicinity. The temperature of the
sulphurous vapours was 117° 7 ; that of the air 69° ; and
that of the sulphurous brook, which is probably cooled in
the upper parts of its course by the snow-waters of the
volcano of Tolima, 84°. 6. The mica-schist, which contains
some pyrites, is permeated by numerous fragments of sul-
phur. The sulphur prepared for sale is principally obtained
from an ochre-yellow loam, mixed with native sulphur and
weathered mica-slate. The operatives (Mestizoes) suffer
from diseases of the eyes and muscular paralysis. When
Boussingault visited the Azufral de Quindiu, 30 years after
me (1831), the temperature of the vapours which he ana-
lysed 78 had so greatly diminished, as to fall below that of the
open air (7 1°!~6), namely to 66°— 68.° The same excellent
observer saw the trachytic rock of the neighbouring volcano
of Tolima, breaking through the mica-schist, in the Quebrada
de Aguas calientes : just as I have very distinctly seen the

77 Blume, Rumphia sire Comment, lotanicce, t. i (1835), pp. 47—59.

"s Humboldt, Essai r/eognostique sur le gisement des Roches dans les
deux Hemispheres, 1823, p. 76 ; Boussingault, in the Annales de Chimie
tt de Physique, t. Hi, 1S33, p. 11.

222 COSMOS.

equally eruptive, black trachyte of the volcano of Tungu-
ragua covering a greenish mica-schist containing garnet near
the rope-bridge of Penipe. As sulphur has hitherto been
found in Europe, not in the primitive rocks as they were
formerly called, but only in the tertiary limestone, in gypsum,
in conglomerates and in true volcanic rocks, its occurrence
in the Azufral de Quindiu (4^° N. lat.) is the more remark-
able, as it is repeated to the south of the equator between
Quito and Cuenca, on the northern slope of the Paramo del
Assuay. In the Azufral of the Cerro Cuello (2° 13' S. lat.).
again in mica-schist, at an elevation of 7980 feet, I met
with a vast bed of quartz,79 in which the sulphur is dissemi-
nated abundantly in scattered masses. At the time of my
journey the fragments of sulphur measured only 6 — 8 inches,
but they were formerly found of as much as 3 — 4 feet in
diameter. Even a naphtha spring rises visibly from mica-
schist in the sea-bottom in the gulf of Cariaco near Cumana.
There the naphtha gives a yellow colour to the surface of the
sea to a distance of more than a thousand feet, and I found
that its odour was diffused as far as the interior of the pen-
insula of Araya.80

"9 With regard to the elevation of Alausi (near Ticsan) on the Cerro
Cuello, see the " Nivellement barome'trique, No. 206," in my Observ.
Astron. vol. i, p. 311.

80 " The existence of a naphtha spring issuing at the bottom of the sea
from a mica-schist, rich in garnets, and diffusing, according to the ex-
pression of the historian of, the Conquista, Oviedo, a " resinous, aromatic,
and medicinal liquid," is an extremely remarkable fact. All those
hitherto known belong to secondary mountains ; and this mode of stra-
tification appeared to favour the idea that all the mineral bitumens (Hat-
chett, Transact. Linncean Society, 1798, p. 129) were due to the destruc-
tion of vegetable and animal matters, or to the ignition of coal. The
phenomenon of the Gulf of Cariaco acquires fresh importance, if we
bear in mind that the same so-called primitive stratum contains subter-
ranean fires, that the odour of petroleum is experienced from time to
time at the edge of ignited craters (for example, in the eruption of
Vesuvius in 1805, when the volcano threw up scoria?), and that most of
the very hot springs of South America issue from granite (las Trin-
cheras, near Portocabello), gneiss and micaceous schist. More to the
eastward of the meridian of Cumana, in descending from the Sierra de
Meapire, we first came to the hollow ground (tierra hueca), which,
during the great earthquakes of 1766, threw up asphalte enveloped in
viscous petroleum ; and afterwards, beyond this ground, to an infinity
of hydrosulphurous hot springs (Humboldt, Relation Historique, t, i,
pp. 136, 344, 347, and 447).

SALSES. 223

If we now cast a last glance at the kind of volcanic
activity which manifests itself by the production of vapours
and gases, either with or without phenomena of combustion,
we find sometimes a great affinity, and sometimes a remark-
able difference in the matters escaping from fissures of the
earth, according as the high temperature of the interior,
modifying the action of the affinities, has acted upon homo-
geneous or very composite materials. The matters which
are driven to the surface by this low degree of volcanic
activity, are : — aqueous vapour in great quantity, chloride of
sodium, sulphur, carburetted and sulphuretted hydrogen,
carbonic acid and nitrogen ; naphtha (colourless or yellowish,
or in the form of brown petroleum) ; boracic acid and alu-
mina from the mud volcanoes. The great diversity of these
matters, of which, however, some (common salt, sulphuretted
hydrogen gas, and petroleum), are almost always associated
together, shows the unsuitableness of the denomination
salses, which originated in Italy, where Spallanzani had the
great merit of having been the first to direct the attention
of geognosists to this phenomenon, which had been long
regarded as so unimportant, in the territory of Modena. The
name vapour and gas springs, is a better expression of the
general idea. If many of them, such as the Fumaroles,
undoubtedly stand in relation to extinct volcanoes, and are
even, as sources of carbonic acid, peculiarly characteristic of a
last stage of such volcanoes ; others, on the contrary, appear
to be quite independent of the true fiery mountains which
vomit forth fused earths. Then, as Abich has already shown
in the Caucasus, they follow definite directions in large tracts
of country, breaking out of fissures in rocks, both in the plains,
even in the deep basin of the Caspian Sea, and in moun-
tain elevations of nearly 8500 feet. Like the true volcanoes,
they sometimes suddenly augment their apparently dor-
mant activity by the eruption of columns of fire, which
spread terror all around. In both continents, in regions
widely separated, they exhibit the same conditions following
one upon the other ; but no observation has hitherto justified
us in supposing that they are the forerunners of the forma-
tion of true volcanoes vomiting lava and cinders. Their
activity is of another kind, perhaps originating at a smaller
depth, and caused by different chemical processes.

224 COSMOS.

d Volcanoes , according to the difference of their formation
and activity. — Action ~by fissures and cauldron-like depres-
sions.— Circumvallation of the craters of elevation. — Vol-
canic conical and hell-shaped Mountains, with open or
closed summits, — Difference of the Rocks through which
Volcanoes act.

(Amplification of the Eepresentation of Nature :
Cosmos, vol. i., pp. 225—247.)

Amongst the various specific manifestations of force in
the reaction of the interior of our planet upon its uppermost
strata, the mightiest is that presented by the true Volcanoes :
— that is to say, those openings through which, besides
gases, solid masses of various materials are forced up from
unmeasured depths to the surface, either in a state of igneous
fusion, as lava streams, or in the form of cinders, or as pro-
ducts of the finest trituration (ashes). If we regard the
words volcano and fiery mountain as synonymous, in accord-
ance with the old usage of speech, we thus, according to a
preconceived and very generally diffused opinion, attach to
the idea of volcanic phenomena, the picture of an isolated
conical mountain, with a circular or oval orifice at the
summit. Such views, however, lose their universality when
the observer has the opportunity of wandering through
connected volcanic districts, occupying a surface of many
thousand square geographical miles ; for example, the entire
central part of the highlands of Mexico, between the Peak
of Orizaba, Jorullo, and the shores of the South Sea; or
Central America ; or the Cordilleras of New Granada and
Quito, between the Volcano of Purace", near Popayan, that
of Pasto and Chimborazo ; or the isthmian chain of the
Caucasus, between the Kasbegk, Elburuz and Ararat. In
lower Italy, between the Phlegraean Fields of the mainland
of Campania, Sicily, and the islands of Lipari and Ponza, as
also in the Greek Islands, part of the intervening land has
not been elevated with the volcanoes, and part of it has
been swallowed by the sea.

In the above-mentioned great districts of America and
the Caucasus, masses of eruptions — (true Trachytes, and not

VOLCANOES. 225

trachytic conglomerates ; streams of obsidian ; quarried
blocks of pumice -stone, and not pumice boulders trans-
ported and deposited by water) — make their appearance,
seeming to be quite independent of the mountains, which
only rise at a considerable distance. Why should not the
surface have been split in many directions during the pro-
gressive refrigeration of the upper strata of the earth by
radiation of heat, before the elevation of isolated mountains
or mountain chains had yet taken place ? Why should not
these fissures have emitted masses in a state of igneous
fusion, which have hardened into rocks and eruptive stones
(trachyte, dolerite, melaphyre, margarite, obsidian, and pu-
mice) ? A portion of these trachytic or doleritic strata which
have broken out in a viscid fluid state, as if from earth-
springs,81 and which were originally deposited in a horizontal
position, have, during the subsequent elevation of volcanic
cones and bell-shaped mountains, been tilted into a position
which by no means belongs to the more recent lavas, pro-
duced from igneous mountains. Thus, to advert in the first
place to a very well-known European example, in the Val
del Bove on Etna (a depression which cuts deeply into the
interior of the mountain) the declination of the strata of
lava, which alternate very regularly with masses of boulders, is
25° to 30°, whilst, according to Elie de Beaumont's exact
determinations, the lava streams which cover the surface of
Etna, and which have only flowed from it since its elevation
in the form of a mountain, only exhibit a declination of 3°
to 5° on an average of 30 streams. These conditions indi-
cate the existence of very ancient volcanic formations,
which have broken out from fissures, before the production
of the volcano as an igneous mountain. A remarkable pheno-
menon of this kind is also presented to us by antiquity ; a
phenomenon which manifested itself on Eubcea, the modern
Negropout, in an extended plain, situated at a distance
from all active and extinct volcanoes. " The violent earth-
quakes, which partially shook the island, did not cease until
an abyss, which had opened on the plain of Lelantus, threw
up a stream of glowing mud (lava)."*8

81 Cosmos, vol. i, p. 229.

82 Strabo i, p. 58, ed. Casaub. The epithet diairvpog, proves that in
this case mud-volcanoea are not spoken of. Where Plato, in his geog-

VOL. V Q.

226 COSMOS.

If the oldest formations of eruptive rock (often perfectly
similar to the more recent lavas in its composition), which
also in part occupy veins, are to be ascribed to a previous
fissure of the deeply shaken crust of the earth, as I have
long been inclined to think, both these fissures, and the less
simple craters of elevation subsequently produced, must be
regarded only as volcanic eruptive orifices, not as volcanoes
themselves. The principal character of these last consists
in a connexion of the deep-seated focus with the atmosphere,
which is either permanent, or at least renewed from time to
time. For this purpose the volcano requires a peculiar frame-
work ; for, as Seneca w says very appropriately, in a letter to
Lucilius, "ignis in ipso monte non alimentum habet, sed
viam." The volcanic activity exerts, therefore, a formative
action by elevating the soil ; and not, as was at one time uni-
versally and exclusively supposed, a building action by the ac-
cumulation of cinders, and new strata of lava, superposed one
upon the other. The resistance experienced in the canal of
eruption, by the masses in a state of igneous fluidity when
forced in excessive quantities towards the surface, gives rise to
the increase in the heaving force. A " vesicular inflation of
the soil " is produced, as is indicated by the regular outward
declination of the elevated strata. A mine-like explosion,
the bursting of the central and highest part of the convex
inflation of the soil gives origin sometimes only to what
Leopold von Buch has called a crater of elevation^ that is
nostic phantasies, alludes to these, mixing mythical matter with ob-
served facts, he says distinctly (in opposition to the phenomenon de-
scribed by Strabo) vypov rrr)\ov Trorajuot. Upon the denominations
TTJjXof and pua%, as volcanic emissions, I have treated on a former
occasion (Cosmos, vol. i, p. 236), and I shall only advert here to
another passage in Strabo (vi, p. 269), in which hardening lava,
called 71-77X6? /iifXag, is most distinctly characterised. In the description
of Etna we find : — "The red-hot stream (pvaZ.) in the act of solidifica-
tion converts the surface of the earth into stone to a considerable
depth, so that whoever wishes to uncover it must undertake the labour
of quarrying. For, as in the craters, the stone is molten and then up-
heaved, the fluid streaming from the summit is a black excrementi-
tious mass (Trr/Xot.) falling down the mountain, which, afterwards har-
dening, becomes a millstone, and retains the same colour that it had
before."

83 Cosmos, vol. i, p. 238.

84 Leopold von Buch, On Basaltic Islands and Craters of Elevationt
in the Abhandl. der kvnig. Akad. der Wiss. zu Berlin, 1818 — 1819, s. 51;

CRATERS OF ELEVATION. 227

to say, a ci-ater-like, round or oval depression, bounded by a
circle of elevation, a ring-shaped wall, usually broken down
in places ; sometimes (when the framework of a perma-
nent volcano is to be completed), to a dome-shaped or
conical mountain in the middle of the crater of elevation.
The latter is then generally open at its summit, and on the
bottom of this opening (the crater of the permanent volcano)
rise transitory hills of eruption and hills of scoriae, small and
large cones of eruption, which, in Vesuvius, sometimes far ex-
ceed the margins of the crater of the cone of elevation. The
signs of the first eruption, the old framework, are not however
always retained. The high wall of rock which surrounds
the inner circular wall (the crater of elevation), is not recog-

and Physicalische Beschreibung der canarischen Inseln, 1825, s. 213,
262, 284, 313, 323, and 341. This work, which constitutes an era in
the profound knowledge of volcanic phenomena, is the fruit of a voyage
to Madeira and Teneriffe from the beginning of April to the end of
October, 1815 ; but Naumann indicates with much justice, in his Lekr-
buch der Geognosie, that in the letters written in 1802 by Leopold von
Buch, from Auvergne (Geognostische Beobacht. auf Reisen durch Deutsch-
land und Italien, Bd. ii, s. 282), in reference to the description of Mont
d'Or, the theory of craters of elevation and their essential difference
from the true volcanoes was already expressed. An instructive coun-
terpart to the three craters of elevation of the Canary Islands (on Gran
Canaria, Teneriffe, and Palma) is furnished by the Azores. The admir-
able maps of Captain Vidal, for the publication of which we are in-
debted to the English Admiralty, elucidate the wonderful geognostic
construction of these islands. On San Michael is situated the enormous
Caldeira das sete Cidades. which was formed in the year 1444, almost
under Cabral's eyes, a crater of elevation which encloses two lakes, the
Lagoa grande and the Lagoa azul, at a height of 876 feet. The Cal-
deira de Corvo, of which the dry part of the bottom is 1279 feet high,
is almost of the same circumference. Nearly three times this height are
the craters of elevation of Fayal and Terceira. To the same kind of
eruptive phenomena belong the innumerable but ephemeral platforms
which were visible only by day, in 1691, in the sea around the island
of San George, and in 1757 around San Michael. The periodical inflation
of the sea-bottom, scarcely four miles to the west of the Caldeira das
sete Cidades, producing a larger and somewhat more permanent island
(Sabrina), has already been mentioned (Cosmos, vol. i, p. 241).
Upon the crater of elevation of Astru»i, in the Phlegnean plains,
and the trachytic mass driven up in its centre, as an unopened bell-
shaped hill, see Leopold von Buch, in Poggend. Annalen. Bd. xxxvii,
s. 171 and 182. A fine crater of elevation is that of Rocca Monfina.
measured and figured in Abich's Geolog. Beobacht. tiber die vulkan,
Erschein. in Unter-und Mittd Italien, 1841, Bd. i, s. 113, Taf. ii.

228 COSMOS.

nisable, even in scattered detritus, on many of the largest
and most active volcanoes.

It is a great merit of modern times not only to have more
accurately investigated the peculiar conditions of the forma-
tion of volcanoes by a careful comparison of those which are
widely separated from each other, but also to have intro-
duced more definite expressions into language, by which the
heterogeneous features of the general outline, as well as
the manifestations of volcanic activity are distinguished.
If we are not decidedly disinclined to all classifications,
because in the endeavour after generalization these always
rest only upon imperfect indications, we may conceive the
bursting forth of fused masses and solid matter, vapours and
gases, in four different ways. Proceeding from the simple
to the complex phenomena, we may first mention eruptions
from fissures, not forming separate series of cones, but pro-
ducing volcanic rocks superlying each other, in a fused
and viscid state ; secondly, eruptions through heaped up
cones, without any circumvallation, and yet emitting streams
of lava, as was the case for five years during the destruction
of the Island of Lancerote, in the first half of the last
century ; thirdly, craters of elevation, with up-heaved strata,
but without central cones, emitting streams of lava only on
the outside of the circumvallation, never from the interior,
which is soon closed up with detritus ; fourthly, closed bell-
shaped mountains or cones of elevation, open at the summit,
either enclosed by a circular wall, which is at least partially
retained, — as on the Pic of Teneriffe, in Fogo, and Rocca
Monfina ; or entirely without circumvallation or crater of
elevation, — as in Iceland,85 in the Cordilleras of Quito, and
the central parts of Mexico. The open cones of elevation of
this fourth class maintain a permanent connection between
the fiery interior of the earth and the atmosphere, which is
more or less effective at undetermined intervals of time.
Of the dome-shaped and bell-shaped trachytic and doleritic
mountains which have remained closed at the summit, there
appear, according to my observations, to be more than of
the open cones whether active or extinct, and far more
than of the true volcanoes. Dome-shaped and bell-shaped

85 Sartorius von Waltershausen, Physisch-geographische Slcizze vor
Island, 1847, s. 107.

CRATERS OP ELEVATION. 229

mountains, such as Chimborazo, Puy de Dome, Sarcouy,
Rocca Monfina and Vultur, give the landscape a peculiar
character, by which they contrast pleasingly with the sch's*
tose peaks, or the serrated forms of limestone.

In the tradition preserved to us so picturesquely by Ovid
regarding the great volcanic phenomenon of the peninsula of
Methone, the production of such a bell-shaped and unopened
mountain is indicated with methodical clearness. " The
force of the winds imprisoned in dark caves of the eartl ,
and seeking in vain for an opening, drive up the heaving
soil (extentam tumefecit humum), as when one fills a bladder
or leather bag with air. By gradual hardening, the high
projecting eminence has retained the form of a hill." I have
already elsewhere adverted to the fact of how completely
different this Roman representation is from Aristotle's
narration of the volcanic phenomenon upon Hiera, a newly
formed Aeolic (Liparian) Island, in which "the subterra-
nean, mightily urging blast does indeed also raise a hill,
but afterwards breaks it up to pour forth a fiery shower
of ashes." The elevation is here clearly represented as
preceding the eruption of flame (Cosmos, vol. i, p 240).
According to Strabo, the elevated dome-like hill of Methana
had also opened in fiery eruptions, at the close of which an
agreeable odour was diffused in the night time. It is very
remarkable that the latter was observed under exactly
similar circumstances during the volcanic eruption of San-
torin, in the autumn of 1650, and was denominated "a
consoling sign, that God would not yet destroy his flock,"
in the penitential sermon delivered and written shortly after-
wards by a monk.86 Does not this pleasant odour afford

86 It has been a much disputed point, to what particular locality of
the plain of Troezen, or the peninsula of Methana, the description of
the Roman poet may refer. My friend, Ludwig Ross, the great Greek
antiquarian and chorograph, who has had the advantage of many tra-
vels, thinks that the immediate vicinity of Troezen presents no locality
which can be referred to as the bladder-lifce hills, and that, by a poetic
license, Ovid has removed the phenomenon described with such truth
to nature, to the plain. " To the south of the peninsula of Methana,
and east of the plain of Troezen," writes Ross, "lies the island Calauria,
well known as the place where Demosthenes, being pressed by the
Macedonians, took poison in the temple of Neptune. A narrow arm of
the sea separates the limestone rocks of Calauria from the coast; from
this arm of the sea (passage, TTO^OI,') the town and island take their present

233 COSMOS.

indications of naphtha ? The same thing is also referred to
by Kotzebue, in his Russian voyage of discovery, in connec-
tion with an igneous eruption (1804) of the volcanic island of
Umnack, newly elevated from the sea in the Aleutian Archi-
pelago. During the great eruption of Vesuvius, on the 12th
August, 1805, which I observed in company with Gay-
Lussac, the latter found a bituminous odour prevailing at
times in the ignited crater. I bring together these little-
noticed facts, because they contribute to confirm the close
concatenation of all manifestations of volcanic activity, the
intimate connection of the weak salses and naphtha springs
with the true volcanoes.

Circumvallations, analogous to those of the craters of ele-
vafcion, also present themselves in rocks which are very
different from trachyte, basalt and porphyritic schists, for
example according to Elie de Beaumont's acute observation,
in the granite of the French Alps. The mountain mass of
Oisans, to which the highest 87 summit of France, Mont
name. In the middle of the strait, united with Calauria by a low cause-
way, probably of artificial origin, lies a small conical islet, comparable
in form to an egg cut through the middle. It is volcanic throughout,
consisting of greyish yellow and yellowish red trachyte, mixed with
eruptions of lava and scoriae, and is almost entirely destitute of vege-
tation. Upon this islet stands the present town of Poros, on the place
of the ancient Calauria. The formation of the islet is exactly similar
to that of the more recent volcanic islands in the Bay of Thera (Santo-
rino). In his animated description, Ovid has probably followed a
Greek original or an old tradition" (Ludw. Eoss, in a letter to me dated
November, 1845). As a member of the French scientific expedition,
Virlet has set up the opinion that the volcanic upheaval may have been
only a subsequent increase of the trachytic mass of the peninsula of
Methana. This increase occurs in the north-west extremity of the
peninsula, where the black burnt rock, called Kammeni-petra, resem-
bling the Kammeni, near Santorin, betrays a more recent origin. Pau-
sanias communicates the tradition of the inhabitants of Methana, that,
on the north coast, before the now celebrated sulphurous springs burst
forth, fire rose out of the earth (see Curtius, Pelopwinesos, Bd. i, s. 42
and 46). On the " indescribable pleasant odour" which followed the
stinking sulphurous odour, near Santorino (Sept. 3650), see Ross,
Reisen auf den griech. Inseln des agaiscken Meeres, Bd. i, s. 196. Upon
the odour of naphtha in the fumes of the lava of the Aleutian island
Umnack, which appeared in 1796, see Kotzebue's Entdeckungs-Reise,
Bd. ii, s. 106, and Leopold de Buch, Description phys. des lies Canaries,
p. 458.

87 The highest summit of the Pyrenees, that is, the Pic de Nethou
(the eastern and highest peak of the Maladetta or Malahita group), has

MAARS. 231

Pelvoux, near Brianc,on, (12,905 feet) belongs, forms an am-
phitheatre of thirty-two geographical miles in circumference,
in the centre of which is situated the small village of la
Berarde. The steep walls of this circular space rise to a height
of more than 9600 feet. The circumvallation itself is gneiss ,
all the interior is granite.88 In the Swiss and Savoy Alps, the
same formation presents itself repeatedly in small dimensions.
The Grand-Plateau of Mont-Blanc, in which Bravais and
Martins encamped for several days, is a closed amphi-
theatre with a nearly flat bottom at an elevation of nearly
12,811 feet; from tne midst of which the colossal pyramid
of the summit rises.89 The same upheaving forces produce
similar forms, although modified by the composition of the
different rocks. The annular and cauldron-like valleys (val-
leys of elevation), described by Hoffman, Buckland, Mur-
chison, and Thurmann, in the sedimentary rocks of the north
of Germany, in Herefordshire, and the Jura mountains of
Porrentruy, are also connected with the phenomena here
described, as well as, although with a less degree of ana-
logy, some elevated plains of the Cordilleras enclosed on all
sides by mountain masses, in which are situated the towns
of Caxamarca (9362 feet), Bogota (8729 feet), and Mexico
(7469 feet), and in the Himalayas the cauldron-like valley
of Caschmir (5819 feet).

Less related to the craters of elevation than to the above
described simplest form of volcanic activity (the action from
mere fissures), are the numerous Maars amongst the extinct
volcanoes of the Eifel ; cauldron-like depressions in non-
volcanic-rock (Devonian slate), and surrounded by slightly
elevated margins, formed by themselves. " These are as
been twice measured trigonometrically ; its height, according to Reboul,
is 11,443 feet (3481 metres), and, according to Coraboeui, 11,167 feet
(3404 metres). It is, therefore, 1705' feet lower than Mont Pelvoux, in
the French Alps, near Brian9on. The next in height to the Pic de
Nethou in the Pyrenees, are the Pic Posets or Erist, and of the group
of the Marbore", the Montperdu, and the Cylindre.

88 Mtmoire pour servir a la Description Geologique dc la France, t. ii.
p. 339. Upon " valleys of elevation" and " encircling ridges" in the
Silurian formation, see the admirable description of Sir Roderick Mur-
chison in " The Silurian System," pt. i, pp. 427 — 442.

89 Bravais and Martins, Observ. faites au Sommet et au Grand
Plateau du Mont-Blanc, in the Annuaire Meteorol. de la France pow
1850, p. 131.

232 COSMOS.

it were the funnels of mines, indications of mine-like erup-
tions," resembling the remarkable phenomenon described by
me of the human bones scattered upon the hill of la Culca *°
during the earthquake of Riobamba (4 February, 1797).
When single Maars, not situated at any great height, in the
Eifel, in Auvergne, or in Java, are filled with water, such
former craters of explosion may in this state be denominated
crater es-lacs ; but it seems to me that this term should not
be taken as a synonymous name for Maar, as small lakes
have been found by Abich and myself on the summits of the
highest volcanoes, on true cones of elevation in extinguished
craters : for example, on the Mexican volcano of Toluca at
an elevation of 12,246 feet, and on the Caucasian Elburuz at
19,717 feet. In the volcanoes of the Eifel we must carefully
distinguish from each other two kinds of volcanic activity of
very unequal age, — the true volcanoes emitting streams of
lava ; and the weaker eruptive phenomena of the Maars.
To the former belong the basaltic stream of lava, rich in
olivine, and cleft into upright columns, in the valley of
Uesbach near Bertrich ;w the volcano of Gerolstein, which
is seated in a limestone containing dolomite, deposited in the
form of a basin in the Devonian grauwacke schists ; and the
long ridge of the Mosenberg (1753 feet above the sea) not
far from Bettenfeld to the west of Manderscheid. The last
named volcano has three craters, of which the first and
second, those furthest to the north, are perfectly round, and
covered with peat mosses ; whilst from the third and most

90 Cosmos, vol. v, p. 173. I have twice visited the volcanoes
of the Eifel, when geognosy was in very different states of de-
velopment, in the autumn of 1794, and in August, 1845; the first
time in the vicinity of the lake of Laach and the monastery there,
which was then still inhabited by monks; the second time, in the
neighbourhood of Bertrich, the Mosenberg, and the adjacent Maars,
but never for more than a few days. As in the latter excursion I had
the good fortune to be able to accompany my intimate friend, the
mining surveyor, Von Dechen, I have been enabled by many years' cor-
respondence, and the communication of important manuscript memoirs
to make free use of the observations of this acute geognosist. I have
often indicated by quotation marks, as is my wont, what I have bor-
rowed, word for word, from his communications.

91 H. von Dechen, Geognost. Uebersicht der Umgegend von Bad £&>••
trick, 1847, s. 11—51.

MAARS, 233

southern98 crater, theie flows down a vast, reddish brown,
deep stream of lava, separated into a columnar form, towards
the valley of the little Kyll. It is a remarkable pheno-
menon, foreign to lava-producing volcanoes in general, that
neither on the Mosenberg nor on the Gerolstein, nor in
other true volcanoes of the Eifel are the lava-eruptions
visibly surrounded at their origin by a trachytic rock, but,
as far as they are accessible to observation, proceed directly
from the Devonian strata. The surface of the Mosenberg
does not at all prove what is hidden in its depths. The
scoriae containing augite, which by cohesion pass into
basaltic streams, contain small, calcined fragments of slate,
but no trace of enclosed trachyte. Nor is the latter to be
found enclosed in the crater of the Rodderberg, notwith-
standing that it lies in the immediate vicinity of the Sieben-
gebirge, the greatest trachytic mass of the Rhine district.

"The Maars appear," as the mining surveyor Von Dechen has
ingeniously observed, " to belong in their formation to about
the same epoch as the eruption of the lava-streams of the
true volcanoes. Both are situated in the vicinity of deeply
cut valleys. The lava-producing volcanoes were decidedly
active at a time when the valleys had already attained very
nearly their present form ; and we also see the most ancient
lava-streams of this district pouring down into the valleys."
The Maars are surrounded by fragments of Devonian slates
and by heaps of gray sand and tufa-margins. The Laacher
lake, wh ether it be regarded as a large Maar, or, with my
old friend C. von Oeynhausen, as part of a large cauldron-
like valley in the clay slate (like the basin of Wehr), ex-
hibits some volcanic eruptions of scoriae upon the ridge sur-
rounding it, as is the case on the Krufter Ofen, the Yeitskopf
and Laacher Kopf. It is not, however, merely the entire want
of lava-streams, such as are to be observed on the Canary
Islands upon the outer margin of true craters of elevation
and in their immediate vicinity, — it is not the inconsiderable

92 Stengel, in Ndggerath, das Gebirye von Rheinland und Westphalen,
Bd. i, s. 79, Taf. iii. See also C. von Oeynhauseii's admirable explana-
tions of his geognostic Map of the Lake of Laach, 1847, pp. 34, 39, and
42, including the Eifel and the basin of Neuwied. Upon the Maars,
see Steininger, Geognostische Beschreibung der Eifel, 1853, s. 113. Hip
earliest meritorious work, " Die erloschenen Vulkane in der Eifel und
am Niedcr-RItein," belongs to the year 1820.

234- COSMOS.

elevation of the ridge surrounding the Maar, that distin-
guishes this from craters of elevation ; the margins of the
Maars are destitute of a regular stratification of the rock,
falling, in consequence of the upheaval, constantly outwards.
The Maars sunk in the Devonian slate, appear, as has already
been observed, like the craters of mines, into which, after
the violent explosion of hot gases and vapours, the looser
ejected masses (Bapillt), have for the most part fallen
back. As examples I shall only mention here the Immera-
ther, the Pulverinaar, and theMeerfelder Maar. In the centre
of the first mentioned, the dry bottom of which, at a depth
of two hundred feet, is cultivated, are situated the two
villages of Ober- and Unter-Immerath. Here, in the vol-
canic tufa of the vicinity, exactly as on the Laacher lake,
mixtures of felspar and augite occur in spheroids, in which
particles of black and green glass are scattered. Similar
spheroids of mica, hornblende and augite, full of vitrified
portions are also contained in the tufa veins of the Pulver-
maar near Gillenfeld, which, however, is entirely converted
into a deep lake. The regularly circular Meerfelder Maar,
covered partly with water and partly with peat, is character-
ized geognostically by the proximity of the three craters of
the groat Mosenberg, the most southern of which has fur-
nished a stream of lava. The Maar, however, is situated
639 feet below the long ridge of the volcano, and at its
northern extremity, not in the axis of the series of craters,
but more to the north-west. The average elevation of the
Maars of the Eifel above the surface of the sea falls be-
tween 922 feet (Laacher lake ?) and 1588 feet (Mosbrucher
Maar).

As this is peculiarly the place in which to call attention
to the uniformity and agreement exhibited by volcanic
activity in its production of material results, in the
most different forms of the outer framework (as Maars,
as circuinvallated craters of elevation, or cones opened
at the summit), I may mention the remarkable abun-
dance of crystallized minerals which have been thrown
out by .the Maars in their first explosion, and which still
in part lie buried in the tufas. In the environs of the
Laacher lake this abundance is certainly greatest, but; other
Maars also, for example the Immerather, and the Meerfelder

MAARS. 235

Maar so rich in bombs of olivine, contain fine crystallized
masses. We may here mention, zircon, hauyne, leucite,93 apa-
tite, nosean, olivine, augite, rhyacolite, common felspar
(orthoclase) , glassy felspar (sanidine), mica, sodalite, garnet,
and titanic iron. If the number of beautifully crystallized
minerals on Vesuvius be so much greater (Scacchi counts
43 species), we must not forget, that very few of them are
ejected from the volcano, and that the greater number belongs
to the portion of the so-called eruptive matters of Vesu-
vius, which, according to the opinion of Leopold von Buch,94
" are quite foreign to Vesuvius, and to be referred to a
tufaceous covering diffused far beyond Capua, which was up-
heaved by the rising cone of Vesuvius, and has probably
been produced by a deeply-seated submarine volcanic action."
Certain definite directions of the various phenomena of
volcanic activity are unmistakeable even in the Eifel. " The
eruptions, producing lava-streams, of the upper Eifel lie in
one fissure, nearly 32 English miles in length, from Bert-

93 Leucite (of the same kind from Vesuvius, from Rocoa di Papa in
the Albanian mountains, from Viterbo, from the Rocca Monfina,
according to Pilla, sometimes of more than 3 inches in diameter, and
from the dolerite of the Kaiserstuhl in the Breisgau), occurs also " in
position as leucite-rock in the Eifel, on the Burgberg, near Rieden.
The tufa in the Eifel incloses large blocks of leucitophyre near Boll
and Weibern." I cannot resist the temptation to borrow the following
important observation from a chemico-geognostic memoir read by Mits-
cherlich a few weeks since before the Academy of Berlin. "Aqueous
vapours alone may have effected the eruptions of the Eifel ; but they
would have divided olivine and augite into the finest drops and pow-
der, if they had met with them in a fluid state. With the funda-
mental mass of the erupted matters fragments of the old, broken up rock
are most intimately mixed, for example on the Dreiser Weiher, and
these are frequently caked together. The larger olivine masses and the
masses of augite even usually occur surrounded by a thick crust of
this mixture ; a fragment of the old rock never occurs in the olivine or
augite, — both were consequently formed before they reached the spot
where the breaking up took place. Olivine and augite had therefore
separated from the fluid basaltic mass before this met with an accumu-
lation of water or a spring which caused its expulsion." See also upon
the bombs an older memoir by Leonard Homer, in the Transactions of
the Geological Society, 2nd series, vol. iv, pt. 2, 1836, p. 467.

94 Leopold von Buch, in Poggend. Annalen, Ed. xxxvii, s. 17P.
According to Scacchi, the eruptive matters belong to the first outbreak
of Vesuvius in the year 79. Leonhard's Neues Jahrbuch fur Mineral
1853, s. 259.

236 COSMOS.

rich to the Goldberg near Ormond, directed from south-
east to north-west ; on the other hand the Maars, from the
Meerfelder Maar to Mosbruch and the Laacher lake, follow
a line of direction from south-west to north-east. These
two primary directions intersect each other in the three
Maars of Daun. In the neighbourhood of the Laacher lake
trachyte is nowhere visible on the surface. The occurrence
of this rock below the surface is only indicated by the pecu-
liar nature of the perfectly felspar-like pumice-stone of
Laach, and by the bombs of augite and felspar thrown out.
But the trachytes of the Eifel, composed of felspar and
large crystals of hornblende, are only visibly distributed
amongst basaltic mountains : as in the Sellberg (1893 feet)
near Quiddelbach, in the rising ground of Struth, near
Kelberg, and in the wall-like mountain chain of Reimerath
near Boos."

Next to the Lipari and Ponza Islands few parts of Europe
have probably produced a greater mass of pumice-stone
than this region of Germany, which, with a comparatively
small elevation, presents such various forms of volcanic
activity in its Maars (crate res d' explosion) , basaltic rocks,
and lava-emitting volcanoes. The principal mass of the
pumice-stone is situated between Nieder Mendig and Sorge,
Andernach and Hiibenach ; the principal mass of the duckstein,
or Trass (a very recent conglomerate, deposited by water),
lies in the valley of Brohl, from its opening into the Rhine
upwards to Burgbrohl, near Plaidt and Kruft. The Trass-
formation of the Brohl- valley contains, together with frag-
ments of grauwacke-slate and pieces of wood, small fragments
of pumice-stone, differing in nothing from the pumice-stone
which constitutes the superficial covering of the region, and
even that of the duckstein itself. Notwithstanding some
analogies which the Cordilleras appear to present, I have
always doubted whether the Trass can be ascribed to erup-
tions of mud from the lava-producing volcanoes of the Eifel.
I rather suppose, with H. von Dechen, that the pumice-
stone was thrown out dry, and that the Trass was formed in
the same way as other conglomerates. "Pumice-stone is
foreign to the Siebengebirge; and the great pumice-eruption
of the Eifel, the principal mass of which- still lies above the
loess (Trass) and alternates therewith in particular parts,

MAARS. 237

may, in accordance with the presumption to which the local
conditions lead, have taken place in the valley of the Rhine,
above Neuwied, in the great Neuwied basin, perhaps near
Urmits, on the leit bank of the Rhine. From the friability
of the material the place of eruption may have disappeared
without leaving any ti-aces, by the subsequent action of the
current of the Rhine. In the entire tract of the Maars of
the Eifel, as in that of its volcanoes from Bertrich to Ormond,
no pumice-stone is found. That of the Laacher lake is limited
to the rocks upon its margin ; and on the other M aars the
small fragments of felspathic rock, which lie in the volcanic
sand and tuff, do not pass into pumice."

We have already touched upon the relative antiquity of the
Maars and of the eruptions of the lava-streams, which differ
so much from them, compared with that of the formation of the
valleys. " The trachyte of the Siebengebirge appears to be
much older than the valley -formation, and even older than the
Rhenish brown-coal. Its appearance has been independent
of the cutting of the valley of the Rhine, even if we should
ascribe this valley to the formation of a fissure. The forma-
tion of the valleys is more recent than the Rhenish brown-
coal, and more recent than the Rhenish basalt ; but older
than the volcanic eruptions with lava-streams, and older
than the great pumice-eruption and the Trass. Basalt for-
mations decidedly extend to a more recent period than the
formation of trachyte, and the principal mass of the basalt is,
therefore, to be regarded £ younger than the trachyte. In
the present declivities \,f the valley of the Rhine many
basaltic groups (the quarry of Unkel, Rolandseck, Godes-
berg), were only laid bare by the opening. of the valley,
as up to that time they were probably enclosed in the Devo-
nian grauwacke rocks."

The Infusoria, whose universal diffusion, demonstrated by
Ehrenberg, upon the continents, in the greatest depths of the
sea and in the upper strata of the atmosphere, is one of the
most brilliant discoveries of our time, have their principal
seat in the volcanic Eifel, in the Rapilli, Trass-strata, and
pumice-conglomerates. Organisms with silicious shields fill
the valley of Brohl and the eruptive matters of Hochsim-
mer ; sometimes, in the Trass, they are mixed with uncar-
bonised twigs of coniferae. According to Ehrenberg, the

238 COSMOS.

whole of this microcosm is of fresh- water formation, and
marine Polythalamia95 only show themselves exceptionally in
the uppermost deposit of the friable, yellowish loess at the
foot and on the declivities of the Siebengebirge (indicating
its former brackish coast-nature).

Is the phenomenon of Maars limited to Western Ger-
many ? Count Montlosier, who was acquainted with the
Eifel by personal observations in 1819, and who pronounces
the Mosenberg to be one of the finest volcanoes that he ever
saw, (like Rozet) regards the Gouffre de Tazenat, the Lac
J?avin and Lac de la G-odivel, in Auvergne, as Maars or
craters of explosion. They are cut into very different kinds
of rock, — in granite, basalt, and domite (trachytic rock), and
surrounded at the margins with scoriae and rapilli.96

The frameworks which are built up by a more powerful
eruptive activity of volcanoes, by upheaval of the soil and
emission of lava, appear in at least six different forms, and
reappear with this variety in their forms in the most distant
zones of the earth. Those who are born in volcanic districts
amongst basaltic and trachytic mountains, are often genially
impressed in spots where the same forms greet them.
Mountain forms are amongst the most important deter-
mining elements of the physiognomy of nature, — they give
the district either a cheerful, or a stern and magnificent cha-
racter, according as they are adorned with vegetation or sur-
rounded by a dreary barrenness. I have quite recently endea-

95 Upon the antiquity of formation of the valley of the Rhine, see
H. von Dechen, Geognost. Besdireibung des Siebengebirges, in the Ver-
handl. des Naturhist. Vereins der Preuss. Rheinlande und Westphalens,
1852, s. 556 — 559. The infusoria of the Eifel are treated of by
Ehrenberg in the Monatsber. der Akad. der Wiss. zu Berlin, 1844,
e. 337, 1845, s. 133 and 148, and 1846, s. 161—171. The Trass of
Brohl, which is filled with crumbs of pumice-stone containing infusoria,
forms hills of as much as 850 feet in height:

96 See Rozet, in the Memoires de la Societe Geologique, 2me serie, t. i,
p. 119. On the island of Java also, that wonderful seat of multifarious
volcanic activity, there occur " craters without cones, as it were flat
volcanoes" (Junghuhn, Java, seine Gestalt und Pflanzendecke, Lief, vii,
p. 640) between Gunung Salak and Perwakti, analogous to the Maars
as " craters of explosion." Destitute of any elevated margins, they are
situated partly in perfectly flat districts of the mountains, have angular
fragments of the burst rocky strata scattered around them, and now
only emit vapours and gases.

TRUE VOLCANOES. 239

voured to bring together, in a separate atlas, a number of out-
lines of the Cordilleras of Quito and Mexico, sketched from my
own drawings. As basalt occurs sometimes in conical domes,
somewhat rounded at the summit, sometimes in the form ol
closely-arranged twin-mountains of unequal elevation, and
sometimes in that of a long horizontal ridge bounded at
each extremity by a more elevated dome, so we principally
distinguish in trachyte the majestic dome-form97 (Chim-
borazo, 21,422 feet), not to be confounded with the form
of the unopened but less massive bell-shaped mountains. The
conical form is most perfectly98 exhibited in Cotopaxi (18,877
feet), and next to this in Popocatepetl99 (17,727 feet), as seen
on the beautiful shores of the lake of Tezcuco, or from the
summit of the .ancient Mexican step-pyramid of Cholula;
and in the volcano of Orizaba100 (17,374 feet, according to
Ferrer 17,879 feet). A strongly truncated conical form1 is
exhibited by the Nevado de Cayambe-Urcu (19,365 feet),
which is intersected by the equator, and by the volcano of
Tolima (18,129 feet), visible above the primaeval forest at
the foot of the Paramo de Quindiu, near the little town of
Ibague.2 To the astonishment of geognosists an elongated
ridge is formed by the volcano of Pichincha (15,891 feet), at
the less elevated extremity of which the broad, still ignited
crater3 is situated.

Fallings of the walls of craters, induced by great natural
phenomena, or their rupture by mine-like explosion from

9' Humboldt, Umrisse von Vullcanen der Cordilleren von Quito und
Mexico, ein Beitrag zur Pliysiognomik der Natur, Tafel iv (Kleinere
Schriften, Bd. i, s. 133—205).

98 Umrisse von Vulkanen, Tafel vi.

99 Op. tit. sup. Tafel viii (Kleinere Schriftin, Bd. i, s. 463—467).
On the topographical position of Popocatepetl (smoking mountain, in
the Aztec language), near the (recumbent) White woman, Iztaccihuatl,
and its geographical relation to the western lake of Tezcuco and the
pyramid of Cholula situated to the eastward, see ray Atlas Geographique
et Physique de la Nouvelle Espagve, pi. 3.

00 Umrisse von Vulkanen, Tafel ix; the Star-mountain, in the Aztec
language Citlaltepetl ; Kleinere Schriften, Bd. i, s. 467 — 470, and my
Atlas Geogr. et Phys. de la Nouvelle Espagne, pi. 17.

1 Umrisse von Vulkanen, Tafel ii.

2 Humboldt, Vues dts Cordilleres et Monumens des peuples indigenes de
lAmerique (fol.), pl.lxii.

3 Umrisse von Vidkanen. Tafel i and x (Kleinere Schriften, Bd. L
a. 1-99).

240 COSMOS.

the depths of the interior produce remarkable and con-
trasting forms in conical mountains : such as the cleavage
into double pyramids of a more or less regular kind in the
Carguairazo (15,667 feet), which suddenly fell in4 on the
night of the 19th July, 1698, and in the still more beautiful
pyramids5 of Ilinissa (17,438 feet) ; and a crenulation of the
upper walls of the crater, in which two very similar peaks,
opposite to each other, betray the previous primitive form
(Capac- Urcu, Cerro del Altar, now only 17,456 feet in
height). Amongst the aborigines of the highlands of Quito,
between Chambo and Lican, between the mountains of
Condorasto and Cuvillan, the tradition has been universally
preserved that fourteen years before the invasion of Huayna
Capac, the son of the Inca Tupac Yupanqui, and after erup-
tions which lasted uninterruptedly for seven or eight years,
the summit of the last-mentioned volcano fell in, and
covered the entire plateau, in which New Riobamba is situ-
ated, with pumice-stone and volcanic ashes. The volcano,
originally higher than Chimborazo, was called in the Inca
or Quichua language, capac, the kins' or prince of mountains
(urcu), because the natives saw its summit rise to a greater
height above the lower snow line, than that of any other moun-
tain of the neighbourhood.6 The great Ararat, the summit

4 Umrisse von Vulkanen, Tafel iv.

5 Ibid. Tafel iii, and vii.

6 Long before the visit of Bouguer and La Condamine (1736) to the
plateau of Quito, long before any measurements of the mountains by
astronomers, the natives knew that Chimborazo was higher than any
other Nevado in that region. They had detected two lines of level
which remained almost exactly the same all the year round, — that of
the lower limit of perpetual snow, — and that of the elevation to
which a single, occasional snow-fall reached down. As in the equatorial
region of Quito, the snow-line, as I have proved by measurements else-
where (Asie Centrale, t. iii, p. 255), only varies about 190 feet in eleva-
tion on six of the most colossal peaks ; and as this variation, as well as
smaller ones caused by local conditions, is imperceptible to the naked
eye when seen from a great distance (the height of the summit of Mont
Blanc is the same as that of the lower equatorial snow-limit), this cir-
cumstance gives rise within the tropics to an apparently uninterrupted
regularity of the snowy covering, that is to say, the form of the snow-
line. The pictorial representation of this horizontally is astounding to
the physicists who are only accustomed to the irregularity of the
enowy covering in the variable, so-called temperate zones. The uni-
formity of elevation of the snow about Quito, and the knowledge of tlia

TRUE VOLCANOES. 241

of which (17,084 feet) was reached by Friedrich Parrot in
the ytar 1829, and by Abich and Chodzko in 1845 and 1850,
forms, like Chimborazo, an mi-opened dome. Its vast lava-
streams have burst forth far below the snow-line. A more
important character in the formation of Ararat is a lateral
chasm, the deeply-cut Valley of Jacob, which may be coin-
pal ed with the Val del Bove of Etna. In this, according to
Abich's observation, the inner structure of the nucleus of
the trachytic dome-shaped mountain, first becomes really
risible, as this nucleus and the upheaval of the whole of
Ararat are much more ancient than the lava-streams.7
The Kasbegk and Tschegem which have broken out upon the
same principal Caucasian mountain ridge (E.S.E. — W.N.W.)
as the Elburuz (19,716 feet) are also cones without craters at
their summits, whilst the colossal Elburuz bears a crater-lake
upon its summit.

As conical and dome-like forms are by far the most fre-
quent in all regions of the earth, the isolated occurrence
of the long ridge of the volcano of Pichinch'a, in the group
of volcanoes of Quito, becomes all the more remarkable. I
have occupied myself long and carefully with the study of
its structure, and, besides its profile view, founded upon

maximum of its oscillation, presents perpendicular bases of 15,777 fee*
above the surface of the sea, and of 6396 feet above the plateau in
which the cities of Quito, Hambato, and Nuevo Riobambaare situated;
bases which, combined with very accurate measurements of angles of
elevation, may be employed for determining distance in many topogra-
phical labours which are to be rapidly executed. The second of the
level-lines here indicated, the horizontal which bounds the lower por-
tion of a single occasional snow-fall, is decisive as to the relative height
of the mountain domes which do not reach into the region of perpetual
snow. Of a long chain of such mountains, which have been erroneously
supposed to be of equal height, many are below the temporary snow-
line, and thus the snow-fall decides as to the relative height. I have
heard such considerations as these upon perpetual and accidental snow-
limits from the mouths of rough country people and herdsmen in the
mountains of Quito, where the Sierras Nevadas are often close together
although they are not connected by the same line of perpetual snow.
Grandeur of nature sharpens the perceptive faculties in paiticular
individuals amongst the coloured aborigines, even when they are on
the lowest steps of civilization.

1 Abich. Bulletin de la Societe de Geographic, 4me se'rie, t. i (1851),
p. 517, with a very beautiful representation of the form of the old
volcano.

VOL. V. B

242 COSMOS.

numerous angular measurements, have also published a topo-
graphical sketch of its transverse valleys.8 Pichiricha forms
a wall of black trachytic rock (composed of augite and oligo-
clase) more than nine miles in length, elevated upon a fissure
in the most western Cordilleras, near the South Sea, but
without the axis of the high mountain ridge coinciding in
direction with that of the Cordillera. Upon the ridge of
the wall, the three domes, set up like castles, follow from
S.W. to N.E. : Cuntur-guachana, Guagua-Pichincha (the
child of the old volcano) and el Picacho de los Ladrillos.
The true volcano is called the Father or the Old Man, Eucu-
Pichincha. It is the only part of the long mountain ridge
that reaches into the region of perpetual snow, and there-
fore rises to an elevation which exceeds the dome of Guagua-
Pichincha; the child, by about 190 feet. Three tower-like
rocks surround the oval crater, which lie somewhat to the
south-west, and therefore beyond the axial direction of a
wall which is on the average 15,406 feet in height. In the
spring of 1802, 1 reached the eastern rocky tower accompanied
only by the Indian, Felipe Aldas. We stood there upon the
extreme margin of the crater, about 2451 feet above the bot-
tom of the ignited chasm. Sebastian Wisse, to whom the phy-
sical sciences are indebted for so many interesting observations
during his long residence in Quito, had the courage to pass
several nights, in the year 1845, in a part of the crater where
the thermometer fell towards sunrise to 28°. The crater is
divided into two portions by a rocky ridge, covered with
vitrified scoriae. The eastern portion lies more than a
thousand ieet deeper than the western, and is now the real
seat of volcanic activity. Here a cone of eruption rises to
a height of 266 feet. It is surrounded by more than seventy
ignited fumaroles, emitting sulphurous vapours.9 From this
circular eastern crater, the cooler parts of which are now
covered with tufts of rushy grasses, and a Pourretia with
Bromelia-like leaves, it is probable that the eruptions of
fiery scoriae, pumice, and ashes of Rucu-Pichincha took
place in 1539, 1560, 1566, 1577, 1580, and 1660. The city

8 Humboldt, Vuts de Cordilleres, p. 295, pi. Ixi, and Atlas dt la
Mat. Hist, du Voyage, pi. 27.
» Kleinere Schriften, Bd. i, s. 61, 81, 83, and 88.

TRUE VOLCANOES. 243

of Quito was then frequently enveloped in darkness for days
together by the falling, dust-like rapilli.

To the rarer class oi volcanic forms which constitute elon-
gated ridges belong, in the old world, the Galungung, with a
large crater, in the western part of Java ;10 the doleritic mass
of the Schiwelutsch, in Kamtschatka, a mountain- chain upon
the ridge of which single domes rise to a height of 10,170
feet ;n Hec'a, seen from the north-west side, in the normal
direction upon the principal and longitudinal fissure over
which it has burst forth, as a broad mountain-chain, fur-
nished with various small peaks. Since the last eruptions of
1845 and 1846, which yielded a lava-stream of 8 geographical
miles in length and in some places more than 2 miles in
breadth, similar to the stream from Etna in 1669, five caldron-
like craters lie in a row upon the ridge of Hecla. As the
principal fissure is directed N. 65J E., the volcano, when seen
from Selsundsfjall, that is from the south-west side, and
therefore in transverse section, appears as a pointed conical
mountain.12

If the forms of volcanoes are so remarkably different
(Cotopaxi and Pichincha) without any variation in the
matters thrown out, and in the chemical processes taking place
in the depths of their interior, the relative position of the
cones of elevation is sometimes still more singular. Upon
the island of Luzon, in the group of the Philippines, the still
active volcano of Taal, the most destructive eruption oi'
which was that of the year 1754, rises in the midst of a
If.rge lake, inhabited by crocodiles (called the laguna de
Bomlon). The cone, which was ascended in Kotzebue's
voyage of discovery, has a crater-lake, from which again a
cone of eruption, with a second crater, rises.13 This descrip-

10 Junghuhn, Reise durch Java, 1845, s. 215, Tafel xx.

11 See Adolf Erraan's Reise um die Erde, which is also very important
in a geognostic point of view, Bd. iii, s. 271 and 207.

12 Sartorius von Waltershausen, Physisch-geographische Skizze von
Island, 1847, s. 107, and his Geognostischer Atlas von Island, 1853,
Tafel xv and xvi.

13 Otto von Kotzebue, Entdeckungs-Reise in die Sildsee und in die
Berings-Strasse, 1815—1818, Bd. iii, s. 68; Reise- Atlas von Choris, 1820,
Tafel 5; Vicointe d'Archiac, Histoire des Progres de la Geologie, 1847,
t. i, p. 544 ; and Buzeta, Diccionario Geogr. estad. Historico de las islat
Filipinos, t.ii (Madrid, 1851), pp.436 and 470—471, in which, however,

244 COSMOS.

tion reminds one involuntarily of Hanno's journal of his
voyage, in which an island is referred to, enclosing a small
lake, from the centre of which a second island rises. The
phenomenon is said to occur twice, once in the Gulf of the
Western Horn, and again in the Bay of the Gorilla Apes, on
the West African coast.14 Such particular descriptions may
be believed to rest upon actual observation of nature !

The smallest and greatest elevation of the points at which
the volcanic energy of the interior of the earth shows itself
permanently active at the surface, is a hypsometric considera-
tion possessing that interest for the physical description of
th£ earth which belongs to all facts relating to the reaction
of the fluid interior of the planet upon its surface. The
degree of the upheaving force16 is certainly evidenced in the
height of volcanic conical mountains, but an opinion as to
the influence of comparative elevation upon the frequency
and violence of eruptions must be given with great caution.
Individual contrasts of the frequency and strength of similar
actions in very high or very low volcanoes, cannot be deci-
sive in this case, and our knowledge of the many hundred
active volcanoes, supposed to exist upon continents and
Islands, is still so exceedingly imperfect that the only deci-
sive method, that of average numbers, is as yet misapplied.
But such average numbers, even if they should furnish the
definite result at what elevation of the cones a quicker
return of the eruptions is manifested, would still leave room
for the doubt that the incalculable contingencies occurring

the double encircling of a crater in the crater-lake, mentioned alike accu-
rately and circumstantially by Delamare, in his letter to Arago (Novem-
ber, 1842, Comptes rcndus de I'Acad. des Sciences, t. xvi, p. 756) is not
referred to. The great eruption in December, 1754 (a previous and
more violent one took place on the 24th September, 1716), destroyed
the old village of Taal, situated on the south-western bank of the lake,
which was subsequently rebuilt at a, greater distance from the volcano.
The small island of the lake upon which the volcano rises is called Isla
del Volcan. (Buzeta loc. cit.) The absolute elevation of the volcano of
Taal is scarcely 895 feet. It is, therefore, like Cosima, one of the lowest.
At the time of the American expedition of Captain Wilkes (1842) it
was in full activity. See United States Exploring Expedition, vol. v.
P. 317.

14 Humboldt, Examen Critique de I' Hist, de la Geogr. t. iii, p. 135;
ffannonis Periplus, in Hudson's Geogr. Greed min. t. i, p. 46.

15 Cosmos, vol. i, p. 227.

TRUE VOLCANOES. 245

in the network of fissures, which may be stopped up with
more or less ease, may act together with the elevation ; that
is to say, the distance from the volcanic focus. The pheno-
menon is consequently an uncertain one, as regards its
causal connexion.

Adhering cautiously to matters of fact, where the compli-
cation of the natural phenomena and the deficiency of histo-
rical records as to the number of eruptions in the lapse of
ages have not yet allowed us to discover laws, I am con-
tented with establishing five groups for the comparative
hypsometry of volcanoes, in which the classes of elevation are
characterised by a small but certain number of examples.
In these five groups I have only referred to conical moun-
tains rising isolated and furnished with still ignited craters,
and consequently to true and still active volcanoes, not to
unopened dome-shaped mountains, such as Chimborazo. All
cones of eruption which are dependent upon a neighbouring
volcano, or which, when at a distance from the latter, as
upon the island of Lancerote, and in the Arso on the
Epomeus of Ischia, have preserved no permanent connection
between the interior of the earth and the atmosphere, are
here excluded. According to the testimony of the most
zealous observer of the vulcanicity of Etna, Sartorius von
Waltershausen, this volcano is surrounded by nearly 700
larger and smaller cones of eruption. As the measured ele-
vations of the summits relate to the level of the sea, the
present fluid surface of the planet, it is of importance here
to advert to the fact that insular volcanoes, — of which some
(such as the Javanese volcano Cosima,16 at the entrance of
the Straits of Tsugar, described by Horner and Tilesius) do
not project a thousand feet, and others, such as the Peak of
Tenerifie,17 are more than 12,250 feet above the surface of

16 For the position of this volcano, which is only exceeded in small-
noss by the volcano of Tanna, and that of the Mendaiia, see the fine
map of Japan by F. von Siebold, 1840.

17 I do not mention here, with the Peak of Teneriffe, amongst the
insular volcanoes, that of Mauna-Roa, the conical form of which does
not agree with its name. In the language of the Sandwich Islanders,
mauna signifies mountain, and roa, both long and much. Nor do I
mention Hawaii, upon the height of which there has so long been a
dispute, and which has been described as a trachytic dome not opened
at the summit. The celebrated crater Kiraueah (a lake of molten,

246 COSMOS.

the sea, — have raised themselves by volcanic forces above a
sea-bottom, which has often been found 20,000 feet, nay, in
one case, more than 45,838 leet, below the present surface of
the ocean. To avoid an error in the numerical proportions
it must also be mentioned that, although distinctions of the
first and fourth classes,— volcanoes of 1000 and 18,000 feet
(1066 and 19,188 English feet)— appear very considerable for
volcanoes on continents, the ratios of these numbers are
quite changed if (from Mitscherlich's experiments upon the
melting point of granite, and the not very probable hypo-
thesis of the uniform increase of heat in proportion to the
depth in arithmetical progression) we infer the upper limit
of the fused interior of the earth to be about 121,500 feet
below the present sea level. Considering the tension of elastic
vapours, which is vastly increased by the stopping of volcanic
fissures, the differences of elevation of the volcanoes hitherto
measured are certainly not considerable enough to be
regarded as a hindrance to the elevation of the lava and other
dense masses to the height of the crater.

Hypsometry of Volcanoes.

First group, from 700 to 4000 Paris or 746 to 4264 English
feet in height.

The volcano of the Japanese i&land Cosima, to the south of Jezo:

746 feet, according to Horner.
The volcano of the Liparian island Volcano: 1305 English feet,

according to F. Hoffmann.18
Gunung Api (signifying Fiery Mountain in the Malay language), the

volcano of the island of Banda : 1949 feet.

boiling lava) lies to the eastward, near the foot of the Mauna-Eoa, accord-
ing to Wilkes, at an elevation of 3970 feet. See the excellent description
in Charles Wilkes' Exploring Expedition, vol iv, pp. 165 — 196.

18 Letter from F. Hoffmann to Leopold von Buch, upon the Geog-
nostic Constitution of the Lipari Islands, in Poggend. Annalen, Bd. xxvi,
1832, s. 59. Volcano, 1268 feet, according to the recent measurement
of C. Sainte-Claire Deville, had violent eruptions of scoriae and ashes in
the year 1444, at the end of the 16th century, in 1731, 1739, and 1771.
Its fumaroles contain ammonia, borate of selenium, sulphuret of
arsenic, phosphorus, and, according to Bornemann, traces of iodine.
The last three substances occur here for the first tinip amongst vol-
canic products (Comptes rendus de I'Acad. des Sciences, t, xliii, 1856,
p. 683).

TRUE VOLCANOES. 247

The volcano of Izalco,19 in the state of San Salvador (in Central
America) which was first ascended in the year 1770, and which
is in a state of almost constant eruption : 2132 feet, according
to Squier.

Gunung Ringgit, the lowest volcano of Java : 2345 feet, according to
Junghuhn.20

Stromboli: 2958 feet, according to F. Hoffmann.

Vesuvius, the Rocca del Palo, on the highest northern margin of the
crater : the average of my two barometrical measurements-1 of 1805
and 1822 gives 3997 feet.

The volcano of Jorullo, which broke out in the elevated plateau of
Mexico- on the 29th September, 1759: 4266 feet.

Second group, from 4000 to 8000 Paris or 4264 to 8528
English feet in height.

Mont PeU, of Martinique : 4707 feet, according to Dupuget.

The Soufriere, of Guadaloupe: 4867 feet, according to C. Deville.

Gunung Lamongan, in the most eastern part of Java: 5341 feet,
according to Junghuhn.

Gunung Tengger, which has the largest crater23 of all the volcanoes of
Java: height at the cone of eruption of Bromo, 7547 feet, accord-
ing to Junghuhn.

The volcano of Osorno (Chili): 7550 feet, according to Fitzroy.

The volcano of Pico24 (Azores) : 7614 feet, according to Captain
Vidal.

The volcano of the island of Bourbon: 8002 feet, according to
Berth.

19 Squier, in the tenth annual meeting of the American Association,
Newhaven, 1850.

20 See Franz Junghuhn's exceedingly instructive work, Java, seine
Gestalt und Pflanzendecke, 1852, Bd. i, s. 99. Ringgit has been nearly
extinct, since its fearful eruption in the year 1586, which cost the lives
of many thousand people.

21 The summit of Vesuvius is, therefore, only 260 feet higher than
the Brock en.

22 Humboldt, Vues des Cordilleres, pi. xliii, and Atlas geogr. et
physique, pi. 29.

*3 Junghuhn, Op. cit. sup. Bd. i, s. 68 and 98.

24 See my Relation ffistorique, t. i, p. 93, especially with regard to
the distance at which the summit of the volcano of the island of Pico
has sometimes been seen. Ferrer's old measurement gave 7918 feot,
and therefore 304 feet more than the certainly more careful survey of
Obtain Vidal in 1843.

248 COSMOS.

Third group, from 8000 to 12,000 Paris or 8528 to 12,792
English feet in height.

The volcano of Awatscha (Peninsula of Kamtschatka), not to be con-
founded25 with the rather more northern Strjdoschnaja Sopka,
which is usually called the volcano of Awatscha by the English
navigators: 8912 feet, according to Erman.

The volcano of Antuco'26 or Anto'io (Chili): 8920 feet, according to
Domeyko.

The volcano of the island of FogcF (Cape Verd Islands) : 91 54 feet,
according to Charles Deville.

The volcano of Schiwelutsch (Kamtschntka) : the north-eastern
summit 10,551 feet, according to Erman.28

25 Erman, in his interesting geognostic description of the volcanoes
of the peninsula of Kamtschatka, gives the Awatschinskaja or Gorelaja
Sopka as 8912 feet, and the Strjeloschnaja Sopka, which is also called
Korjaskaja Sopka, as 11,822 feet (Reise, Bd. iii, s. 494 and 540). See
with regard to these two volcanoes, of which the former is the most
active, Leopold de Buch, Descr. Physique des Ites Canaries, pp. 447 —
450. Erman's measurement of the volcano of Awatscha agrees best
with the earliest measurements of Mongez (8739) during the expedition
of La Perouse (1787), and with the more recent one of Captain Beechy
(9057 feet). Hofmann in Kotzebue's voyage, and Lenz in Lutke's
voyage, found only 8170 and 8214 feet ; see Lutke, Voyage autour du
Monde, t. iii, pp. 67 — 84. The admiral's measurement of the Strjelo-
schnaja Sopka gave 11,222 feet.

26 See Pentland's table of elevations in Mrs. Somerville's Physical
Geography, vol. ii, p. 452 ; Sir Woodbine Parish, Biienos-Ayres and the
Province of the Rio de la Plata, 1852, p. 343; Poppig, Reise in Chile wid
Peru, Bd. i, s. 411—434.

27 Is it probable that the height of the summit of this remarkable
volcano is gradually diminishing ? A barometrical measurement by
Baldey, Vidal, and Mudge, in the year 1819, gave 2975 metres or 9760
feet ; whilst a very accurate and practised observer, Sainte-Claire
Deville, who has done such important service to the geognosy of
volcanoes, only found 2790 metres or 9154 feet in the year 1842
(Voyage aux lies Antilles et a Vile de Fogo, p. 155). Captain King
had a little while before determined the height of the volcano of
Fogo to be only 2686 metres or 8813 feet.

28 Erman, Reise, Bd. iii, s. 271, 275, and 297. The volcano Schiwe-
lutsch, like Pichincha, has a form which is rare amongst active vol-
canoes, namely, that of a long ridge (chrebet), upon which single domes
and crests (grebni) rise. Dome-shaped and conical mountains are
always indicated in the volcanic district of the peninsula by the name
eopki.

TRUE VOLCANOES. 249

Etna.39 according to Smyth, 10,871 feet.

Peak of Tencriffe: 12.161 feet, according to Charles Deville.30

The volcano Gunung Semeru, the highest of all mountains on the

island of Java: 1^,237 feet, according to Junghuhu's barometrical

measurement.

The volcano Erebus, lat. 77° 32', the nearest to the south pole .31
12,366 feet, according to Sir James Rosa.

The volcano Argceus,32 in Cappadocia, now Erdschisch-Dagh, south-
south-east of Kaisarieh : 12,603 feet, according to Peter von
Tschichatscheff.

29 For an account of the remarkable agreement of the trigonome-
trical with the barometrical measurement of Sir John Herschel, see
Cosmos, vol. i, p. 6.

30 The barometrical measurement of Sainte-Claire Deville (Voy. aux
Antilles, pp. 102—118), in the year 1842, gave 3706 metres or 12,161
feet, nearly agreeing with the result (12,184 feet) of Borda's second
trigonometrical measurement in the year 1776, which I was enabled to
publish for the first time from the manuscript in the De'pot de la
Marine (Humboldt, Voy. aux Regions Equinox, t. i, pp. 116 and 275 —
287). Borda's first trigonometrical measurement, undertaken in con-
junction with Pingre" in the year 1771, gave, instead of 12,1 84 feet,
only 11,142 feet. The. cause of the error was the false reading of an
angle (33' instead of 53'), as was told me by Borda himself, to whose
great personal kindness I was indebted for much useful advice before
my voyage on the Orinoco.

31 I follow Peutland's estimate of 12,367 feet, especially because
in Sir James Ross' Voyage of Discorery in the Antarctic Regions,
vol. i, p. 216, the height of the volcano, the eruptions of smoke and
flame from which were seen even in the day time, is given in round
numbers at 12,400 feet.

32 With regard to Argseus, which Hamilton was the first to ascend and
measure barometrically (at 12,708 feet or 3905 metres), see Peter von
Tschichatscheff, Asie Mineure (1853), t. i, pp. 441—449, and 571. In his
excellent work (Researches in Asia Minor), William Hamilton obtained
as the mean of one barometrical measurement and several angles of
elevation 13,000 feet; but if the height of Kaisarieh is 1000 feet less
than he supposes, it would be only 12,000 feet. See Hamilton, in Trans.
Geolog. Societi/, vol. v, pt. 3, 1840, p. 596. Towards the south-east from
Argseus (Erdschisch Dagh) in the great plain of Eregli, numerous very
email cones of eruption rise to the south of the village of Karabunar
and the mountain group Karadscha-Dagh. One of these, furnished
with a crater, has a singular shape like that of a ship, running out in
front like a beak. This crater is situated in a salt lake, on the road
from Kambunar to Eregli, at a distance of fully four miles from the
former place. The hill bears the same name (Tschichatscheff, t. i, p. 455;
William Hamilton, Researches in Asia Minor, vol. ii, p. 217).

250 COSMOS.

Fourth group, from 12,000 to 16,000 Paris or 12,792 to
17,056 English feet in lieigU.

The volcano of Tugiieres,33 in the highlands of the Provincia de Ion

Pastes: 12,824 feet, according to Eoussingault.
The volcano of Pasto:™ 13,453 feet, according to Boussingault.
The volcano Mauna-Roar* 13,761 feet, according to Wilkes.
The volcano of Cumbal,™ in the Provincia de los Pastos: 15,621

feet, according to Boussingault.

The volcano KliutschewsW7 (Kamtschatka) : 15,766 feet, according
to Erman.

The volcano Rucu-Pichincha : 15,926 feet, according to Humboldt'a
barometrical measurements.

33 The height here given is properly that of the grass-green mountain
lake, Laguna verde, on the margin of which is situated the solfatara
examined by Boussingault (Acosta, Viajes Cientificos a, los Andes Ecuato-
riales, 1849, p. 75).

34 Boussingault succeeded in reaching the crater, and determined
the altitude barometrically ; it agrees very nearly with that which I
made known approximately 23 years before, on my journey from
Popayau to Quito.

35 The altitude qf few volcanoes has been so over-estimated as that
of the Colossus of the Sandwich Islands. We see it gradually fall from
18,410 feet (the estimate given in Ccok's third voyage), 16,486 feet in
King's, and 16,611 feet in Marchand's measurement, to 13,761 feet by
Captain Wilkes, and 13,524 feet by Horner in Kotzebue's voyage.
The grounds of the last-mentioned result were first made known by
Leopold von Buch in the Description Physique des lies Canaries, p. 379.
See Wilkes, Exploring Expedition, vol. iv, pp. Ill — 162. The eastern
margin of the crater is only 13,442 feet. The assumption of a greater
height, considering the asserted freedom from snow of the Mauna-Roa
(lat. 19° 28'; would also be in contradiction to the result that according
to my measurements in the Mexican continent in the same latitude, the
limit of perpetual snow has been found at 14,775 feet (Humboldt,
Voyage aux Regions Equinox, t. i, p. 97; Asie Centrale, t. iii, p. 2C9 and
359).

36 The volcano rises to the west of the village of Cumbal, which is
itself situated 10,565 feet above the sea-level (Acosta, p. 76).

37 I give the result of Erman's repeated measurements in September,
1829. The height of the margin of the crater is exposed to alterations
by frequent eruptions, for in August, 1828, measurements which might
inspire et^ual confidence gave an altitude of 16,033 feet. Compare
Erman's Physikalische Beobaclitungen auf einer Reise um die Erde, Bd. i,
s. 400 and 419, with the historical account of the journey, Bd. iii,
g. 358—360.

TRUE VOLCANOES. 251

The volcano TunguraJiua : 16,494 feet, according to a trgonometrical
measurement33 by Kumboldt.

The volcano of Purace,39 near Popayan: 17,010 feet, according to
Jos£ Caldaa.

Fifth group, from 16,000 to more than 20,000 Paris or from
17,056 to 21,320 English feet in height.

The volcano Sangay, to the south-west of Quito: 17,128 feet, ac-
cording to Bouguer and La Condamine.40

The volcano Popocatepetl:41 17,729 feet, according to a trigonometri-
cal measurement by Humboldt.

The volcano of Orizaba:4'2 17,783 feet, according to Ferrer.

38 Bouguer and La Condamine, in the inscription at Quito, give
16,777 feet for Tungurahua before the great eruption of 1772, and the
earthquake of Riobamba (1797), which gave rise to great depressions of
mountains. In the year 1802 I found the summit of the volcano trigo-
nometrically to be ouiy 16,494 feet.

39 The barometrical measurement of the highest peak of the Volcan
de Purace" by Francisco Jose Caldas, who, like my dear friend and
travelling companion, Carlos Montufar, fell a sacrifice to his love for
the independence and freedom of his country, is given by Acosta
(Viajes Cientifaos, p. 70) at 5184 metres (17,010 feet). I found the
height of the small crater, which emits sulphureous vapours with a
violent noise (Aznfral del Boqueron) to be 14,427 feet; Humboldt,
Recueil d'Observ. Astronomiques et d' Operations Trigonometriques, vol. i,
p. 304.

40 The Sangay is extremely remarkable from its uninterrupted activity
and its position, being removed somewhat to the eastward from the
eastern Cordillera of Quito, to the south of the Rio Pastaza, and at a
distance of 120 miles from the nearest coast of the Pacific, — a position
which (like that of the volcanoes of the Celestial mountains in Asia)
by no means supports the theory according to which the eastern Cor-
dilleras of Chili are free from volcanic eruptions on account of their
distance from the sea. The talented Darwin has not omitted referring
in detail to this old and widely diffused volcanic littoral theory in the
Geological Observations on South America, 1846, p. 185.

41 I measured Popocatepetl, which is also called the Volcan
Grande de Mexico, in the plain of Tetimba, near the Indian village San
Nicolas de los Ranchos. It seems to me to be still uncertain which of
the two volcanoes, Popocatepetl or the pe;ik of Orizaba, is the highest
(see Humboldt, Receuil d'Observ. Astron., vol. ii, p. 543).

42 The peak of Orizaba, clothed with perpetual snow, the geogra-
phical position of which was quite erroneously indicated on all maps
before my journey, notwithstanding the importance of this point for

252 COSMOS.

ELias Mount43 (on the west coast of North America): 17,855 feet,
according to the measurements of Quadra and Galeano.

The volcano of Tolima:** 18,143 feet, according to a trigonometrical
measurement by Humboldt.

The volcano of Arequipa:45 18,883 feet, according to a trigonome-
trical measurement by Dolley.

navigation near the landing-place in Vera Cruz, was first measured
trigonometrically from the Encero by Ferrer, in 1796. The measure-
ment gave 17,879 feet. I attempted a similar operation in a small
plain near Xalapa. I found only 17,375 feet, but the angles of eleva-
tion were very small, and the base line difficult to level. See Humboldt,
Essai Politique sur la Nouv. Espagne, 2me e"d. t. i, 1825, p. 166 ; Atlas
du Mexique (Carte des fausses positions), pi. x, and Kleinere Schriften,
Bd. i, s. 468.

43 Humboldt, Essai sur la Geographic des Plantes, 1807, p. 153. The
elevation is uncertain, perhaps more than ^th too high.

44 I measured the truncated cone of the volcano of Tolima, situated at
the northern extremity of the Paramo de Quindiu, in the Valle del
Carvajal, near the little town of Ibague, in the year 1802. The moun-
tain is also seen at a great distance upon the plateau of Bogota*. At
this distance Caldas obtained a tolerably approximate result (18,430
feet) by a somewhat complicated combination in the year 1806 ; Sem,a-
nario de la Nueva Granada, nueva edition, aumentada por J. Acosta,
1849, p. 349.

45 The absolute altitude of the volcano of Arequipa has been so
variously stated that it becomes difficult to distinguish between mere
estimates and actual measurements. Dr. Thaddaus Hanke, of Prague,
the distinguished botanist of Malaspina's voyage round the world,
ascended the volcano of Arequipa in the year 1796, and found at the
summit a cross which had been ereuted there 12 years before. By a
trigonometrical operation Hanke found the volcano to be 3180 toises
(20,235 feet) above the sea. Thih altitude, which is far too great, was
probably the result of an erroneous assumption of the elevation of the
town of Arequipa, in the vicinity of which the operation was performed.
Had Hanke been provided with a barometer, a botanist entirely unprac-
tised in trigonometrical measurements, would certainly not have resorted
to such means after ascending to the summit. The first who ascended
the volcano after Hanke was Samuel Curzou, from the United States
of North America (Boston Philosophical Journal, 1823, November,
p. 168). In the year 1830 Pentland estimated the altitude at 5600
metres (18,374 feet1), and I have adopted this number (Annuaire du
Bureau des Longitudes, 1830, p. 325) for my Carte Hypsometrique de la
Cordillere des Andes, 1831. There is a satisfactory agreement (within
Tyth) between this and the trigonometrical measurement of a French
naval officer, M. Dolley, for which I was indebted in 1826 to the kind
communication of Captain Alphonse de Moges in Paris. Dolley found

TRUE VOLCANOES. 253

The volcano Cotopaxi:*6 18,881 feet, according to Bouguer.

The volcano Sahama*7 (Bolivia) : 22,354 feet, according r,o Pentland,

The volcano with which the fifth group ends is more than

the summit of the volcano of Arequipa (trigonometrically) to be
11,031 feet, and the summit of Charcani 11,860 feet above the plateau
in which the town of Arequipa is situated. If now we fix the town of
Arequipa at 7841 feet, in accordance with the barometrical measurements
of Pentland and Rivero (Pentland, 7852 feet in the Table of Altitudes
to the Physical Geography of Mrs. Somerville, 3rd ed. vol. ii, p. 454;
Rivero, in the Memorial de Ciencias Naturales, t. ii, Lima, 1828, p. 65 ;
Meyen, Reise urn die Erde, Theil. ii, 1835, s. 5), Dolley's trigonometrical
operation will give for the volcano of Arequipa 18,881 feet (2952 toises),
and for the volcano Charcani,, 19,702 feet (3082 toises). But Pentland's
Table of Altitudes, above cited, gives for the volcano of Arequipa
20,320 English feet, 6190 metres (19,065 Paris feet), that is to say,
1945 feet more than the determination of 1830, and somewhat too iden-
tical with Hanke's trigonometrical measurement in the year 1796 ! In
opposition to this result the volcano is stated, in the Anales de la Uni-
versidad de Chile, 1852, p. 221, only at 5600 metres or 18,378 feet: con-
sequently 590 metres lower ! A sad condition of hypsometry !

46 Boussingault, accompanied by the talented Colonel Hall, has nearly
reached the summit of Cotopaxi. He attained, according to barome-
trical measurement, to an altitude of 5746 metres or 18,855 feet. There
was only a small space between him and the margin of the crater, but
the great looseness of the snow prevented his ascending further. Per-
haps Bouguer's statement of altitude is rather too small, as his compli-
cated trigonometrical calculation depends upon the hypothesis as to the
elevation of the city of Quito.

47 The Sahama, which Pentland (Annuaire du Bureau des Longi-
tudes, 1830, p. 321) distinctly calls an active volcano, is situated,
according to his new map of the Vale of Titicaca (1848), to the east-
ward of Arica in the western Cordillera. It is 928 feet higher than
Chimborazo, and the relative height of the lowest Japanese volcano
Cosima to the Sahama is as 1 to 30. I have hesitated in placing the
Chilian Aconcagua, which, stated by Fitzroy in 1835 at 23.204 feet,
is, according to Pentland's correction, 23,911 feet, and according
to the most recent measurement (1845) of Captain Kellet of the
frigate Herald, 23,004 feet, in the fifth group, because from the
contradictory opinions of Miers ( Voyage to Chili, vol. i, p. 283) and
Charles Darwin (Journal of Researches into the Geology and Natural
History of the Various Countries -visited by the Beagle, 2nd ed. p. 291),
it remains doubtful whether this colossal mountain is a still ignited
volcano. Mrs. Somerville, Pentland, and Gilliss (Naval Attr. Exped.
vol. i, p. 126), also deny its activity. Darwin says : — " I was surprised
at hearing that the Aconcagua was in action the same night (15th
January, 1835), because this mountain most rarely shows any sign of
action."

254 COSMOS.

twice as high as Etna, and five times and a half as high aa
Vesuvius. The scale of volcanoes that I have suggested, start-
ing from the lowly Maars (mine-craters without a raised
framework, which have cast forth olivine bombs surrounded
by half-fused fragments of slate) and ascending to the still
burning Bahama 22,354 feet in height, has shown us that
there is no necessary connexion between the maximum oi
elevation, the smaller amount of the volcanic activity and
the nature of the visible species of rock. Observations con-
fined to single countries may readily lead us to erroneous
conclusions. For example, in the part of Mexico which
lies in the torrid zone, all the snow-covered mountains,
that is to say the culminating points of the whole country,
are certainly volcanoes ; and this is also usually the case
in the Cordilleras of Quito, if the dome-shaped trachytic
mountains, not opened at the summit (Chimborazo and
Corazon), are to be associated with volcanoes ; on the other
hand, in the eastern chain of the Bolivian Andes, the
highest mountains are entirely non- volcanic. The Uevados
of Sorata (21,292 feet), and Illimani (21, 153 feet) consist of
grauwacke schists, which are penetrated by porphyritic
masses,48 in which (as a proof of this penetration), fragments
of schist are enclosed. In the eastern Cordillera of Quito,
south of the parallel of 1° 35' the high summits (Condorasto,
Cuvillan. and the Collanes) lying opposite to the trachytes,
and also entering the region of perpetual snow, are also
mica-slate and firestone. According to our present know-
ledge of the mineralogical nature of the most elevated parts

48 These penetrating porpliyritic masses show themselves in peculiar
vastness, near the Illimani, in Cenipampa (15,949 feet) and Totora-
pampa (13,709 feet); and a quartzose porphyry containing mica, and
enclosing garnets and at the same time angular fragments of silicious
schist forms the superior dome of the celebrated argentiferous Cerro de
Potosi (Pentland in MSS. of 1832). The Illimani, which Pentland
estimated first at 7315 (23,973 feet), and afterward sat 6445 (21, 139 feet)
metres, has also been, since 1847, the object of a careful measurement
by the engineer Pissis, who, on the occasion of his great trigonometrical
survey of the Llanura de "Bolivia, found the Illimani to be on the ave-
rage 6509 metres (21,349 feet) in height, by three triangles between
Calamarca and La Paz : this only differs about 64 metres (210 feet) from
Pentland' s last determination. See Investigadones Sobre la Altitud de
los Andes, in the Anales de Chile, 1852, p. 217 and 221.

TRUE VOLCANOES. 2.55

of the Himalaya, which we owe to the meritorious labours
of B. H. Hodgson, Jacquemont, Joseph Dal ton Hooker,
Thomson, and Henry Strachey, the primary rocks, as they
were formerly called, granite, gneiss and mica-slate, appear to
be visible here also, although there are no trachy tic formations.
In Bolivia, Pentland has found fossil shells in the Silurian
schists on the Nevado de Antacaua, 17,482 feet above the
sea, between La Paz and Potosi. • The enormous height to
which from the testimony of the fossils collected by Abich
from Daghestan, and by myself from the Peruvian Cordil-
leras (between Guambos and Montan), the chalk formation
is elevated, reminds us very vividly that non-volcanic sedi-
mentary strata, full of organic remains, and not to be con-
founded with volcanic tufaceous strata, show themselves in
places where for a long distance around, melaphyres,trachytes,
dolerites, and other pyroxenic rocks, which we regard as the
seat of the upheaving, urging forces, remain concealed in the
depths. In what immeasurable tracts of the Cordilleras and
the districts bordering them upon the east, is no trace of
any granitic formation visible !

The frequency of the eruptions of a volcano, appearing
to depend, as I h:*ve already repeatedly observed, upon mul-
tifarious and very complicated causes, no general law can
safely be established with regard to the relation of the abso-
lute elevation to the frequency and degree o"f the renewal of
combustion. If in a small group the comparison of Strom-
boli, Vesuvius, and Etna, may mislead us into the belief
that the number of eruptions is in an inverse ratio to the
elevation of the volcanoes, other facts stand in direct con-
tradiction to this proposition. Sartorius von Waltershausen,
who has done such good service to our knowledge of Etna,
remarks that on the average furnished by the last few centu-
ries, an eruption of this volcano is to be expected every six
years, whilst in Iceland, where no part of the island is really
secure from destruction by submarine fire, the eruptions of
Hecla, which is 5756 feet lower, are only observed every 70
or 80 years.49 The group of volcanoes of Quito presents a
still more remarkable contrast. The volcano of Sangay,
17,000 feet in height, is far more active than the little conical
mountain Stromboli (2958 feet) ; it is of all known volca-

49 Sartorius von Waltershausen, Skizze von Island, s. 103 and 107

256 COSMOS.

noes the one which exhibits, every quarter of an houi, the
greatest quantity of fiery, widely-luminous eruptions of
scoriae. Instead of losing ourselves in hypotheses upon
the causal relations of inaccessible phenomena, we will rather
dwell here upon the consideration of six points of the surface
of the earth, which are peculiarly important and instructive
in the history of volcanic activity, — Stromboli, the Lycian
Chimoera, the old volcano of JMJasaya, the very recent one
of Izalco, the volcano Fogo on the Cape Verd Islands, and
the colossal Sangay.

The Ghimara in Lycia, and Stromboli, the ancient Stron-
gyle, are the two igneous manifestations of volcanic activity,
the historic proof of whose permanence extends the furthest
back. The conical hill of Stromboli, a doleritic rock, is
twice the height of the island of Volcano (Hiera, Thermessa),
the last great eruption of which occurred in the year 1775.
The uninterrupted activity of Stromboli is compared by
Strabo and Pliny with that of the island of Lipari, the
ancient Meligunis ; but they ascribe to " its flame," that is,
its erupted scorise, " a greater purity and luminosity, with
less heat." M The number and form of the small fiery
chasms are very variable. Spallanzani's description of the
bottom of the crater, which was long regarded as exaggerated
has been completely confirmed by an experienced geog-
nosist, Friedrich Hoffmann, and also very recently, by an
acute naturalist, A. de Quatrefages. One of the incandes-
cent chasms has an opening of only 20 feet in diameter ; it
resembles the pit of a blast furnace, and the ascent and
overflow of the fluid lava, are seen in it every hour, from a
position on the margin of the crater. The ancient, perma-
nent eruptions of Stromboli still sometimes serve for the
guidance of the mariner, and, as amongst the Greeks and
Romans, afford uncertain predictions of the weather, by
the observation of the direction of the flame and of the ascend.

50 Strabo, lib. vi, p. 276, ed. Casaubon ; Pliny, Hist. Nat. iii, 9 : —
" Strongyle, quae a Lipara liquidiore flainma tantuaa differt; e cujui
fumo quinam flaturi siiit venti, in triduo prsedicere incolae traduntur."
See also Urlichs, Vindicice Pliniance, 1853, Fasc. i, p. 39. The volcano
of Lipara (in the north-eastern part of the island), once so active,
appears to rae to have been either the Monte Campo Bianco, or the
Monte di Capo Castagno. (See Hoffmann, in Poggend. Annalen, Bd. xxvi,
*. 49--54.)

TBTTE VOLCANOES. 257

ing column of vapour. Polybius, who displays a singularly
exact knowledge of the state of the crater, connects the
multifarious signs of an approaching change of wind, with
the myth of the earliest sojourn of JEolus upon Strongyle,
and still more with observations upon the then violent fire
upon Volcano (the " holy island of Hepha3stos"). The fre-
quency of the igneous phenomena has of late exhibited some
irregularity. The activity of Stromboli, like that of Etna,
according to Sartorius von Waltershausen, is greatest in
November and the winter months. It is sometimes inter-
niDted by isolated intervals of rest j but these, as we learn
from the experience of centuries, are of very short dura-
tion.

The CTiimcera in Lycia, which has been so admirably
described by Admiral Beaufort, and to which I have twice
referred,51 is no volcano, but a perpetual burning spring — a
51 Cosmos, vol. i, p. 220, and vol. v, p. 212. Albert Berg, who had
previously published an artistic work, Physiognomic der Tropischen
Vegetation von Siidamerika, visited the Lycian Chimaera, near Delik-
tasch and Yanartasch, from Rhodes and the Gulf of Myra in 1853.
(The Turkish word tdsch signifies stone, as ddgh and tdgh, signify moun-
tain; deliktasch signifies perforated stone, from the Turkish, delik, a
hole.} The traveller first saw the serpentine rocks near Adrasau, whilst
Beaufort met with the dark-coloured serpentine deposited upon lime-
stone, and perhaps deposited in it, even near the island Garabusa (not
Grambusa), to the south of Cape Chelidonia. " Near the ruius of the
ancient temple of Vulcan rise the remains of a Christian church in the
later Byzantine style : the remains of the nave and of two side chapels.
In a fore-court, situated to the east, the flame breaks out of a fire-place-
like opening about 2 feet broad and 1 foot high in the serpentine rock.
It rises to a height of 3 or 4 feet and (as a naphtha-spring ?) diffuses a
pleasant odour, which is perceptible to a distance of 40 paces. Near
this large flame, and without the chimney-like opening, numerous very
small, constantly ignited, lambent flames make their appearance from
subordinate fissures. The rock which is in contact with the flame is
much blackened, and the soot deposited is collected to alleviate
smarting of the eye-lids and especially for colouring the eye-brows.
At a distance of three paces from the flame of the Chimaera the heat
which it diffuses is scarcely endurable. A piece of dry wood ignites
when it is held in the opening and brought near the flame without
touching it. Where the old ruined walls lean against the rock, gas also
pours forth from the interstices of the stones of the masonry, and this,
probably from its being of a lower temperature or differently composed
does not iguite spontaneously, but whenever it is brought in contact
with a light. Eight feet below the great flame in the interior of the
ruins there is a *<Hind opening, 6 feet in depth, but only 3 feet wide,

VOL. V. S

258 COSMOS.

gas spring always ignited by the volcanic activity of the
interior of the earth. It was visited a few months ago by
a talented artist, Albert Berg, for the purpose of making a
picturesque survey of this locality, celebrated even in periods
of high antiquity (since the times of Ctesias and Scylax of
Caryanda), and of collecting the rocks from which the
Chimsera breaks forth. The descriptions of Beaufort, Pro-
fessor Edward Forbes, and Lieutenant Spratt in the " Travels
in Lycia" are completely confirmed. An eruptive mass of
serpentine rock penetrates the dense limestone in a ravine,
which ascends from south-east to north-west. At the north-
western extremity of this ravine, the serpentine rocV is cut
off, or perhaps only concealed, by a curved ridge of limestone
rocks. The fragments brought home are partly green and
fresh, partly brown and in a weathered state. In both
serpentines diallage is clearly recognisable.

The volcano of Masaya*- the fame of which was already
widely spread in the beginning of the 16th century, under
the name of el Injlerno de Masaya, and gave occasion for
reports to the Emperor Charles V., is situated between the
two lakes of Nicaragua and Managua, to the south-west of
the charming Indian village of Nindiri. For centuries to-
gether it presented the same rare phenomenon that we have

which was probably arched over formerly, as a spring of water breaks
out in it in the wet seasons, near a fissure over which a small flame
plays." (From the traveller's manuscripts.) On a plan of the locality,
Berg shows the geographical relations of the alluvial strata, of the
(tertiary?) limestone, and of the serpentine rocks.

52 The oldest and most important notice of the volcano of Masaya
is contained in a manuscript of Oviedo's, first edited fourteen years ago
by the meritorious historical compiler, Ternaux-Compans, — Historia de
Nicaragua (cap. v to x), see pp. 115 — 197. The French translation
forms one volume of the Voyages, Relations et Memoires Originaux pour
iervir a VHistoire et a la Decouverte de I'Amerique. See also Lopez de
Gomara, Historia General de las Indias (Zaragoza, 1553), fol. ex, b; and
amongst the most recent works, Squier, Nicaragua, its People, Scenery,
and Monuments, 1853, vol. i, p. 211 — 223, and vol. ii, p. 17. So widely
famed was the incessantly active volcano of Masaya, that a special
monograph of this mountain exists in the royal library at Madrid,
under the title of Entrada y Descubrimiento del Volcan de Masaya,
gue estd en la Prov. de Nicaragua, fecha por Juan Sanchez del
Portero. The author was one of those who let themselves down into
the crater in the wonderful expeditions of the Dominican monk, Fray
Bias de Inesta (Oviedo, Hist, de Nicaragua, p. 141).

TRUE VOLCANOES. 259

described in the volcano of Stromboli. From the margin of
the crater, the waves of fluid lava, set in motion by vapours,
were seen rising and falling in the incandescent chasm. The
Spanish historian, Gonzalez Fernando de Oviedo, first
ascended the Masaya in July 1529, and made comparisons
with Vesuvius, which he had previously visited (1501), in
the suite of the Queen of Naples as her xefe de guardaropa.
The name Masaya, belongs to the Chorotega language
of ^Nicaragua, and signifies burning mountain. The volcano,
surrounded by a wide lava-field (mal-pays), which it has
probably itself produced, was at that time reckoned amongst
the mountain group of the "nine burning Maribios." In its
ordinary condition, says Oviedo, the surface of the lava,
upon which black scoriae float, stands several hundred feet
below the margin of the crater ; but sometimes the ebullition
is suddenly so great, that the lava nearly reaches the upper
margin. The perpetual luminous phenomenon, as Oviedo
definitely and acutely states, is not caused by an actual
flame,53 but by vapours illuminated from below. It is saiu to
have been of such intensity that on the road from the volcano
towards Granada, at a distance of more than three leagues,
the illumination of the district was almost equal to that of
the full moon.

Eight years after Oviedo, the volcano was ascended by
the Dominican monk, Fray Bias del Castillo, who enter-

53 In the French translation of Ternaux-Compans (the Spanish
original has never been published), we find at pp. 123 and 132 : — "It
cannot, however, be said precisely that a flame issues from the crater,
but a smoke as hot as fire ; it is not seen from far during the day, but
is well seen at night. The volcano gives as much light as the moon a
few days before it is at the full." This old observation upon the pro-
blematical mode of illumination of a crater, and the strata of air lying
above it, is not without importance, on account of the doubt, so often
raised in recent times, as to the disengagement of hydrogen gas from
the craters of volcanoes. Although in the ordinary condition here indi-
cated the Hell of Masaya did not throw out scoriae or ashes (Gomara
adds, cosa que hazen otros volcanes], it has nevertheless sometimes had
true eruptions of lava; the last of which probably occurred in the year
1670. Since that date the volcano has been quite extinct, after a
perpetual luminosity had been observed for 140 years. Stephens, who
ascended it in 1840, found no perceptible trace of ignition. Upon the
Chorotega language, the signification of the word Masaya, and the Mari-
bios, see Buschmann's ingenious ethnographical researches, Ueber die
Aztekischen Ortsnamen, s. 130, 140, and 171.

S 2

260 COSMOS.

tained the absurd opinion that the fluid lava in the crater
was liquid gold, and associated himself with an equally avari-
cious Flemish Franciscan, Fray Juan de Gandavo. The
pair availing themselves of the credulity of the Spanish
settlers, established a joint-stock company to obtain the
metal at the common cost. They themselves, Oviedo adds
satirically, declared that as ecclesiastics they were free
from any pecuniary contributions. The report upon the
execution of this bold undertaking, which was sent to the
Bishop of Castilla del Oro, Thomas de Verlenga, by Fray
Bias del Castillo (the same person who is denominated Fray
Bias de Tnesta in the writings of Gomara, Benzoni, and
Herrera), was only made known (in 1840) by the discovery
of Oviedo's work upon ^Nicaragua. Fray Bias, who had pre-
viously served on board ship as a sailor, proposed to imitate
the method of hanging upon ropes over the sea, by which
the natives of the Canary Islands collect the colouring mat-
ter of the Orchil {Lichen Roccella), on precipitous rocks.
For months together all sorts of preparations were made, in
order to let down a beam of more than 30 feet in length, by
means of a windlass and crane, so that it might project over
the deep abyss. The Dominican, his head covered with an
iron helmet and a crucifix in his hand, was let down with
three other members of the association ; they remained for
a whole night in this part of the solid crater bottom, from
which they made vain attempts to dip out the supposed
liquid gold with earthen vessels, placed in an iron pot.
Not to frighten the shareholders they agreed6* that,

54 « The three companions agreed to say that they had found great
riches ; and Fray Bias, whom I had known as an ambitious man, gives,
in his relation, the oath which he and his associates took upon the
Gospel, to persist for ever in their opinion that the volcano contained
gold and silver in a state of fusion!" Oviedo, Descr. de Nicaragua, cap. x,
pp. 186 and 196). The Cronista de las Indias is, however, very indig-
nant (cap. 5) that Fray Bias narrated that " Oviedo had begged the Hell
of Masaja from the Emperor as his armorial bearings." Such a geog-
nostic memento would certainly not have been in opposition to the
heraldic customs of the period, for the courageous Diego de Ordaz, who
boasted of having reached the crater of the Popocatepetl when Cortez
first penetrated into the valley of Mexico, bore this volcano as an
heraldic distinction, as did Oviedo the constellation of the Southern
Cross, and earliest of all Columbus (Exam. crit. t. iv, pp. 235 — 240), a
fragment of a map of the Antilles.

TRUE VOLCANOES. 261

when they were drawn up again they should say that they
had found great riches, and that the Infierno of Masaya,
deserved in future to be called el Paraiso del Masaya. The
operation was afterwards repeated several times, until the
Governor of the neighbouring city of Granada, conceived
some suspicion of the deceit, or perhaps of a fraud upon the
revenue, and forbad any " further descents on ropes into the
crater.'* This took place in the summer of 1538 ; but in
1551 Juan Alvarez, the Dean of the Chapter of Leon, again
received from Madrid the naive permission "to open the
volcano, and procure the gold that it contained." Such was
the popular credulity of the sixteenth century ! But even in
Naples in the year 1822, Monticelli and Covelli were obliged
to prove by chemical analysis, that the ashes thrown out
from Vesuvius onthe 28th October contained no gold ! M

The volcano of Jzalco, situated on the west coast of Cen-
tral America, 32 miles northwards from San Salvador, and
eastward from the harbour of Sonsonate, broke out 1 1 years
after the volcano of Jorullo, deep in the interior of Mexico.
Both eruptions took place in a cultivated plain, and after
the prevalence of earthquakes and subterranean noises
(bramidos) for several mouths. A conical hill rose in the
Llano de Izalco, and with it simultaneously an eruption of
lava poured from its summit on the 23rd February, 1770. It
still remains undecided, how much is to be attributed, in the
rapidly increasing height, to the upheaval of the soil, and
how much to the accumulation of erupted scoriae, ashes and
tufa-masses ; only this much is certain, that since the first erup-
tion, the new volcano, instead of soon becoming extinguished
like Jorullo, has remained uninterruptedly active, and often
serves as a beacon light for mariners near the landing place
in the Bay of Acajutla. Four fiery eruptions are counted
in an hour, and the great regularity of the phenomenon has
astonished its few accurate observers.6* The violence of the
eruptions was variable, but not the time of their occurrence.
The elevation which the volcano of Izalco has now attained
since the last eruption of 1825, is calculated at about 1600
feet, nearly the same as the elevation of Jorullc above the

55 Humboldt, Views of Nature, p. 368.

56 Squier, Nicaragua, its People and Monuments, vol. ii, p. 104. (John
Bailey, Central America, 1850, p. 75).

262 COSMOS.

original cultivated plain ; but almost four times that of
the crater of elevation (Monte Nuovo) in the Phlegrsean
Fields, to which Scacchi67 ascribes a height of 432 feec
from accurate measurement. The permanent activity of
the volcano of Izalco, which was long considered as a
safety-valve for the neighbourhood of San Salvador, did
not however preserve the town from complete destruction
on Easter eve in this year (1854).

One of the Cape Yerd Islands, which rises between S. Jago
and Brava, early received from the Portuguese the name of
llha do Fogo, because, like Stromboli, it produced fire uninter-
ruptedly from 1680 to 1713. After a long repose, the vol-
cano of this island resumed its activity in the summer of
the year 1798, soon after the last lateral eruption of the
Peak of Teneriffe in the crater of Chahorra, which is errone-
ously denominated the volcano of Chahorra as if it were a
distinct mountain.

The most active of the South American volcanoes, and
indeed of all those which I have here specially indicated, is
the Sangay, which is also called the Volcan de Macas, because
the remains of this ancient city, so populous in the early
period of the Conquista, are situated upon the Rio TJpano,
only 28 geog. miles to the south of it. The colossal mountain,
17,128 feet in height, has risen on the eastern declivity of
the eastern Cordillera, between two systems of tributaries of
the Amazons, those of the Pastaza and the TJpano. The
grand and unequalled fiery phenomenon which it now ex-
hibits, appears only to have commenced in the year 1728.
During the astronomical measurements of degrees by Bou-
guer and La Condamine (1738 to 1740), the Sangay served
as a perpetual fire signal.68 In the year 1802, I myself
heard its thunder for months together, especially in the
early morning, in Chillo, the pleasant country seat of the
Marquis de Selvaletjre near Quito, as half a century pre-
viously, Don Jorge Juan had perceived the ronquidos del

57 Memorie geologiche sulla Campania, 1849, p. 61. I found the
height of the volcano of Jorullo to be 1682 feet above the plain in
which it rose, and 4266 feet above the sea-level.

58 La Condamine, Journal du Voyage a VEquateur, p. 163; and in
the Mesure de Trois Degres de la Meridienne de I' Hemisphere Austral,
p. 56.

TRUE VOLCANOES. 263

Sangay, somewhat further towards the north-east, near
Pinibac, at the foot of the Antisana.59 In the years 1842
and 1843, when the eruptions were associated with most
noise, the latter was heard most distinctly not only in the
harbour of Guayaquil, but also further to the south along
the coast of the Pacific Ocean, as far as Payta and San

59 In the country house of the Marquis of Selvalegre, the father of my
unfortunate companion and friend, Don Carlos Montufar, one was often
inclined to ascribe the bramidos, which resembled the discharge of a
distant battery of heavy artillery, and which with the same wind, the
same clearness of the atmosphere and the same temperature, were so
extremely unequal in their intensity, not to the Sangay, but to the Guaca-
mayo, a mountain forty miles nearer, at the foot of which a road leads
from Quito, over the Hacienda de Antisana to the plains of Archidona
and the Rio Napo. (See my special map of the province Quixos,
No. 23 of my Atlas geogr. et phys. de FAmerique, 1814 — 1834). Don
Jorge Juan, who heard the Sangay thundering when closer to it than I
have been, says decidedly that the bramidos, which he calls ronquidos
del Volcan (Relation del Viage d la America Meridional, pt. i, t. 2,
p. 569), and perceived in Pintac, a few miles from the Hacienda de
Chillo, belong to the Sangay or Volcan de Macas, whose voice, if I may
make use of the expression, is very characteristic. This voice appeared
to the Spanish astronomer to be peculiarly harsh, for which reason he
calls it a snore (un ronquido) rather than a roar (bramido). The very
disagreeable noise of the volcano Pichincha, which I have frequently
heard at night in the city of Quito, without its being followed by any
earthquake, has something of a clear rattling sound as though chains were
rattled, and masses of glass were falling upon each other. On the Sangay,
Wisse describes the noise to be, sometimes tike rolling thunder, some-
times distinct and sharp, as if one were in the vicinity of platoon firing.
Payta and San Buenaventura (in the Choco) where the bramidos of the
Sangay, that is to say, its roaring, were heard, are distant from the
summit of the volcano in a south-western direction, 252 and 348 geog.
miles. (See Carte de la Prov. Du Choco, and Carte hypsometrique des Cor-
dilleres, Nos. 23 and 3 of my A tlas Geogr. et Physique). Thus, in this
mighty spectacle of nature, reckoning in the Tungurahua and the Coto-
paxi, which is nearer to Quito, and the roar of which I heard in
February, 1803, in the Pacific Ocean (Kleinere Schriften, Bd. i, s. 384),
the voices of four volcanoes are perceived at adjacent points. The
ancients also mention " the difference of the noise," emitted at different
times on the ^Eolian Islands by the same fiery chasm (Strabo, lib. vi.
p. 276). During the great eruption (23rd January, 1835) of the
volcano of Conseguina, which is situated on the coast of the Pacific, at,
the entrance of the Bay of Fonseca, in Central America, the subterranean
propagation of the sound was so great, that it was most distinctly per-
ceived on the plateau of Bogota", at a distance equal to that from Etna
to Hamburgh (Acosta. Viajes Cicntificos de M. Boussingault d los Andes,
1849, a. 56).

264 COSMOS.

Buenaventura, at a distance equal to that of Berlin from
Basle, the Pyrenees from Fontainebleau, or London from
Aberdeen. Although, since the commencement of the pre-
sent century, the volcanoes of Mexico, New Granada, Quito,
Bolivia, and Chili have been visited by some geognosists, the
Sangay, which exceeds the Tungurahua in elevation, has un-
fortunately remained entirely neglected, in consequence of
its solitary position, at a distance from all roads of commu-
nication. It was only in December 1849 that an adventurous
and highly informed traveller, Sebastian Wisse, after a sojourn
of five years on the chain of the Andes, ascended it, and
nearly reached the extreme summit of the snow-covered, pre-
cipitous cone. He not only made an accurate chronometric
determination of the wonderful frequency of the eruptions,
but also investigated the nature of the trachyte which, con-
fined to such a limited space, breaks through the gneiss. As
has already been remarked,80 267 eruptions were counted in
one hour, each lasting on an average 13". 4, and, which is
very remarkable, unaccompanied by any concussion percep-
tible on the ashy cone. The erupted matter, enveloped in
much smoke, sometimes of a gray and sometimes of an
orange colour, is principally a mixture of black ashes and
rapilli, but it also consists partly of cinders, which rise per-
pendiculai'ly, are of a globular form and a diameter of 15 or
16 inches. In one of the more violent eruptions, however,
Wisse counted only 50 or 60 red hot stones as being simul-
taneously thrown out. They usually fall back again into
the crater, but sometimes they cover its upper margin, or
• /isible by their luminosity at a distance, glide down at night,
upon a portion of the cone, which, when seen from a great
way off, probably gave origin to the erroneous notion of La
Condamine, " that there was an effusion of burning sulphur
and bitumen." The stones rise singly one after the other, so
that some of them are falling down, whilst others have only
just left the crater. By an exact determination of time, the
visible space of falling (calculated therefore to the margin of
the crater) was ascertained to be on the average only 786
feet. On Etna, according to the measurements of Sartorius
von Waltershausen and the astronomer D. Christian Peters,
the ejected stones attain an elevation of as much as 2665
60 Cosmos, see page 182.

TRUE VOLCANOES. 265

feet above the walls of the crater. Gemellaro's estmates
during the eruption of Etna in 1832. gave even three
times this elevation ! The black, erupted ashes form layers
of three or four hundred feet in thickness upon the decli-
vities of the Sari ofay for a circle of nearly fourteen miles in
circumference. The colour of the ashes and rapilli gives the
upper part of the cone a fearfully stern character. We must
here again call attention to the colossal size of this volcano,
which is six times greater than that of Stromboli, as this
consideration is strongly in opposition to the absolute belief
that the lower volcanoes always have the most frequent
eruptions.

The grouping of volcanoes is of more importance than
their form and elevation, because it relates to the great
geological phenomenon of upheaval upon fissures. These
groups, whether according to Leopold von Buch, they rise in
lines, or united around a central volcano, indicate the parts
of the crust of the earth, where the eruption of the fused
interior has found the least resistance, in consequence either
of the reduced thickness of the rocky strata, of their natural
structure, or of their having been originally fissured. Three
degrees of latitude are occupied by the space in which the
volcanic energy is formidably manifested in Etna, in the
^Eolian Islands, in Vesuvius, and the parched land (the Phle-
grsean Fields) from Puteoli (Dic£earchia) to Cumse, and as far
as the fire- vomiting Epopeus on Ischia, the Tyrrhenian island
of Apes, ^Enaria. Such a connexion of analogous phenomena
could not escape the notice of the Greeks. Strabo says, " The
whole sea commencing from Cumse as far as Sicily is pene-
trated by fire, and has in its depths certain conduits commu-
nicating with each other and with the continent.61 In such a

61 See Strabo, lib. v, p. 248, Casanbou : — t\ti KoiXmc Tirdc; and
lib. vi, p. 276. Upon a double mode of production of islands the
geographer of Amasia expresses himself (vi, p. 258) with much geolo-
gical acumen. " Some islands," says he (and he names them), " are
fragments of the mainland ; others have proceeded from the sea, as still
happens. For the islands of the high sea (those which lie far out in
the sea) were probably upheaved from the depths ; whilst, on the con-
trary, it is more reasonable to consider those situated at promontories
and separated by a strait, as torn from the mainland." The small group
of the Pithecusae consists of Ischia, originally called ^Enaria, and Procida
(Prochyta). The reason why this group was considered to be an ancient
habitation of apes, why the Greeks and the Italian Tyrrhenians, conse-

266 COSMOS.

(combustible) nature, as all describe it, appear, not only Etna,
bat also the districts around JMcsearchia and Naples, and
around Baiae and Pithecusa ;" and from this arose the fable
that Typhon lay under Sicily, and that, when he turned him-
self, flames and water burst forth, nay sometimes even small
islands with boiling water. " Frequently between Strongyle
and Lipara (in this wide district) flames have been seen burst-
ing forth at the surface of the sea, the fire opening itself a
passage out of the cavities in the depths and pressing upwards
with force." According to Pindar69 the body of Typhon is of

quently Etruscans, gave it such a name (apes were called apipoi, in the
Tyrrhenian; Strabo, lib. xiii, p. 626) remains very obscure> and is per-
haps connected with the myth, according to which the old inhabitants
were transformed into apes by Jxipiter. The name of the apes, aptpoi,
might relate to Arima or Arimer of Homer (Iliad, ii, 783) and Hesiod
(Theog. v. 301). The words tiv 'Apt/ioic of Homer, are contracted into
one word in some codices, and in this contracted form we find the
name in the Roman writers (Virgil, JEneid, ix, 716 ; Ovid, Meta-
morph. xiv, 88). Pliny (Hist. Nat. iii, 5) even says decidedly : —
" ^Enaria, Homero Inarime dicta, Grsecis Pithecusa." ....
The Homeric country of the Arimer, Typhon's resting-place, was
sought, even in ancient times in Cilicia, Mysia, Lydia, in the volcanic
Pithecusse, at the crater Puteolanus, and in the Phrygian Phlegrsea,
beneath which Typhon once lay, and even in the Katakekaumene.
That apes should have lived within historical times upon Ischia, at such
a distance from the African coast is the more improbable, because, as
I have already observed elsewhere, the ancient presence of the apes
upon the Rock of Gibraltar does not appear to be proved, since Edrisi
(in the 12th century) and other Arabian geographers, who describe the
Straits of Hercules in such detail, do not mention them. Pliny also
denies the apes of ^Enaria, but derives the name of the Pithecusse in a
most improbable manner from TtiQoQ, dolium (a figlinis doliorum).
" It appears to me," says Bockh, " to be the main point in this investi-
gation, that Inarima is a name of the Pithecusse produced by learned
interpretation and fiction, just as Corey ra became Scheria ; and that
uEneas was probably only connected with the Pithecusse (JSneae
insulse) by the Romans, who find their progenitors everywhere in
these regions. ISTaevius also testifies to their connection with -5Cneas in
the first book of the Punic War."

62 Pind. Pyth. i, 31. See Strabo, v, pp. 245 and 248, and xiii, p. 627.
We have already observed (Cosmos, vol. v, p. 208), that Typhon fled
from the Caucasus to Lower Italy, as though the myth would
indicate that the volcanic eruptions in the latter country were of
leas antiquity than those upon the Caucasian Isthmus. The consi-
deration of mythical views in popular belief cannot be separated either
from the geography or the history of volcanoes. The two often reci-
procally illustrate each other. That which was regarded upon the

TKUE VOLCANOES. 267

such extent that " Sicily and the sea-girt heights above
Cumse (called Phlegra, or the burnt field,) lie upon the
shaggy breast of the monster."

Thus Typhon (the raging Enceladus) was, in the popular
fancy of the Greeks, the mythical symbol of the unknown
cause of volcanic phenomena lying deep in the interior of
the earth. By the position and the space which he occupied
were indicated the limitation and the co-operation of parti-
cular volcanic systems. In the fanciful geological picture of
the interior of the earth, in the great contemplation of the

surface of the earth as the mightiest of moving forces (Aristotle,
Meteorol. ii, 8, 3), the wind, the inclosed pneuma, was recognised as the
universal cause of vulcanicity (of fire-vomiting mountains and earth-
quakes). Aristotle's contemplation of nature was founded upon the
mutual action of the external and the internal subterranean air, upon
a theory of transpiration, upon differences of heat and cold, moisture
and dryness (Aristotle, Meteor, ii, 8, 1, 25, 31, and ii, 9, 2). The greater
the mass of the wind inclosed " in subterranean and submarine pas-
sages," and the more it is obstructed in its natural, essential property of
moving far and quickly, the more violent are the eruptions. " Vis
fera ventorum, csecis iuclusa cavernis" (Ovid, Metamorph. xv, 299).
Between the wind and the fire there is a peculiar relation. (To Tri'p
orav /itrd TTVIVHCLTOQ y, yivtrai <p\b% KOI (ptptrai Ta\kw^ ; Aristotle,
Meteorol. ii, 8, 3. — KCLI yap TO irvp olov irvivfiaroQ TIQ <j>vait; ; Theo-
phrastus, De Igne, § 30, p. 715). The wind (pneuma) suddenly set
free from the clouds, sends the consuming and widely luminous
lightning flash (Tro/jcrrTyp). " In the Phlegrsea, the Katakekaumene of
Lydia," says Strabo (lib. xiii, p. 628), "three chasms, fully forty
stadia from each other, are still shown, which are called the wind-
bags ; above them lie rough hills, which are probably piled up by the
red-hot masses blown up." He had already stated (lib. i, p. 57) "that
between the Cyclades (Thera and Therasia) flames of fire burst forth
from the sea for four days together, so that the whole sea boiled and
burnt ; and an island composed of calcined masses was gradually raised
as if by a lever." All these well described phenomena are ascribed
to the compressed wind, acting like elastic vapours. Ancient physical
science troubled itself but little about the peculiar essentials of mate-
rial bodies; it was dynamic, and depended on the measure of the moving
force. We find the opinion that the increasing heat of the planet with
the depth is the cause of volcanoes and earthquakes, first expressed
towards the close of the third century by a Christian bishop in Africa
tinder Diocletian (Cosmos, vol. v, p. 196). The Pyriphlegethon of
Plato, as a stream of fire circulating in the interior of the earth,
nourishes all lava-giving volcanoes, as we have already mentioned
in the text. In the earliest presentiments of humanity, in a narrow
circle of ideas, lie the germs of that which we now think we may
explain under the form of other symbols.

268 COSMOS.

universe which Plato establishes in the Phsedo (p. 112 — •
11 4) this co-operation is still more boldly extended to all
volcanic systems. The lava-streams derive their materials
from the Pyriphlegethon, which " after it has repeatedly
rolled around beneath the earth," pours itself into Tartarus.
Plato says expressly that the fire-vomiting mountains, wher-
ever such occur upon the earth, blow upwards small portions
from the Pyriphlegethon (" OUTO? Sea-rlv ov iTrovopa^ovai
Tlvpi(f)\e?ye0oi>ra, ov KOI ol pvatce? airoaTraa fiend ava<J)va{caivt
oirr) av Tv^wai rrj<i 7^?"). This expression (p. 113 B.) of the
expulsion with violence refers to a certain extent to the
moving force of the previously enclosed wind, then suddenly
breaking through, upon which the Stagirite afterwards, in
the Meteorology, founded his entire theory of vulcanicity.

According to these ancient views the linear arrangement of
volcanoes is more distinctly characterized in the consideration
of the entire body of the earth, than their grouping around a
central volcano. The serial arrangement is most remarkable in
those places where it depends upon the situation and exten-
sion of fissures, which, usually parallel to each other, pass
through great tracts of country in a linear direction (like
Cordilleras). Thus, to mention only the most important
series of closely approximated volcanoes, we find in the
new continent those of Central America, with their appen-
dages in Mexico ; those of New Granada and Quito, of Peru,
Bolivia, and Chili ; in the old continent the Sunda Islands
(the Indian Archipelago, especially Java), the peninsula of
Kamtschatka and its continuation in the Kurile Islands,
and the Aleutian Islands, which bound the nearly closed
Behring's Sea on the south. We shall dwell upon some of
the principal groups ; individual details, by being brought
together, lead us to the causes of phenomena.

The linear volcanoes of Central America, according to the
older denominations the volcanoes of Costa Rica, Nicaragua,
San Salvador, and Guatemala, extend from the volcano
Turrialva near Cartago to the volcano of Soconusco, over
six degrees of latitude, between 10° 9 and 16° 2, in a line
the general direction of which is from S.E. to N.W., and
which, with the few curvatures which it undergoes, has a
length of 540 geog. miles. This length is about equal to the
distance from Vesuvius to Prague The most closely ap-

TRUE VOLCANOES. 269

proximated of them, as if they had broken out upon one
and the same fissure only 64 miles in length, are the eight
volcanoes, situated between the Laguna de Managua and
the Bay of Fonseca, between the volcano of Momotombo
and that of Conseguina, the subterranean noise of which
was heard in Jamaica and on the highlands of Bogota in
the year 1835 like the fire of artillery. In Central America
and the whole southern part of the new continent, and
generally from the Chonos Archipelago in Chili to the most
northern volcanoes of Mount Edgecombe on the small island
near Sitka,63 and Mount Elias on Prince William's Sound, for
a length of 6400 geog. miles, the volcanic fissures have every-
where broken out in the western part, or that nearest to the
Pacific Ocean. Where the line of the Central American vol-
canoes enters with the volcano of Conchagua into the state
of San Salvador, in the latitude of 13^° (to the north of
the Bay of Fonseca) the direction of the volcanoes changes
at once with that of the west coast. The series of the
former then strikes E.S.E. — W.N.W. ; indeed, where the
burning mountains are again so closely approximated that
five, still more or less active, are counted in the sliort dis-
tance of 120 miles, the direction is nearly E. — W. This
deviation corresponds with a great dilatation of the conti-
nent towards the east in the peninsula of Honduras, where
the coast tends also suddenly, exactly east and west, from
Cape Gracias a Dios to the Gulf of Amatique for 300 miles,
after it had been previously running from north to south
for the same distance. In the group of elevated volcanoes
of Guatemala (lat. 14° 10') the series again acquires its old
direction, N. 45° W., which it continues as far as the Mexi-
can boundary towards Chiapa and the isthmus of Huasa-
cualco. North- West of the volcano of Soconusco to that

63 Mount Edgecombe, or the St. Lazarus mountain, upon the small
island (Croze's Island, near Lisiansky), which is situated to the west-
ward, near the northern half of the larger island Sitka or Baranow, in
Norfolk Sound, was seen by Cook, and is a hill partly composed of
basalt abounding in olivine, and partly of felspathic trachyte. Its
height is only 2770 feet. Its last great eruption, which produced
much pumice-stone, was in the year 1796 (Lutke*, Voyage autour
dn Monde, 1836, t. iii, p. 15). Eight years afterwards Captain Lisiansky
reached the summit, which contains a crater-lake. He found at that
time no signs of activity anywhere on the mountain.

270 COSMOS.

of Tuxtla, not even an extinct trachytic cone has been
discovered ; in this quarter, granite abounding in quartz
and mica-schist predominate.

The volcanoes of Central America do not crown the ad-
jacent mountain chains, but rise along the foot of the
latter, usually completely separated from each other. The
greatest elevations lie at the two extremities of the series.
Towards the South, in Costa Rica, both seas are visible
from the summit of the Irasu (the volcano of Cartago),
to which, besides its elevation (11,081 feet), its central
position contributes. To the south-east of Cartago there
stand mountains of ten or eleven thousand feet : the
CUriqui (11,262 feet) and the Pico Blanco (11,740 feet).
We know nothing of the nature of their rock, but they
are probably unopened trachytic cones. Further towards
the south-east, the elevations diminish in Yeragua to six
and five thousand feet. This appears also to be the
average height of the volcanoes of Nicaragua and San Sal-
vador; but towards the north-western extremity of the
whole series, not far from the new city of Guatemala, two
volcanoes again rise above 13,000 feet. The maxima con-
sequently fall into the third group of my attempted hyp-
sometric classification of volcanoes, coinciding with Etna
and the Peak of Teneriffe, whilst the greater number of
the heights lying between the two extremities, scarcely
exceed Vesuvius by 2000 feet. The volcanoes of Mexico,
New Granada, and Quito belong to the fifth group, and
usually attain an elevation of more than 17,000 feet.

Although the continent of Central America increases
considerably in breadth from the isthmus of Panama,
through Veragua, Costa Rica, and Nicaragua, to the lati-
tude of 11^°, the great area of the lake of Nicaragua and
the small elevation of its surface (scarcely 128 feet64 above
the two seas), gives rise to such a degradation of the land
exactly in this district, that by it an overflow of air from
the Caribbean Sea into the Great South Sea is often caused,
bringing danger to the voyager in the so-called Pacific

84 Even under the Spanish Government in 1781, the Spanish engi-
neer, Don Jose" Galisteo, had found for the surface of the Laguna of
Nicaragua an elevation only six feet greater than that given by Baily in hia
different levellings in 1838 (Humboldt, Relation Historique. t. iii, p. 321).

TRUE VOLCANOES. 271

The north- east storms thus excited have received
the name of Papagayos, and sometimes rage without inter-
mission for four or five days. They have the remarkable
peculiarity that, during their continuance the sky usually
remains quite cloudless. The name is borrowed from the part
of the west coast of Nicaragua between Brito or Cabo
Desolado and Punta S. Elena (from 11° 22' to 10° 50'),
which is called Golfo del Papagayo, and includes the small
bays of Salinas and S. Elena to the south of the Puerto
de San Juan del Sur. On my voyage from Guayaquil to
Acapulco, I was able to observe the Papagayos in all their
violence and peculiarity for more than two whole days
(9th — llth March, 1803), although rather more to the
south, in less than 9° 13' of latitude. The waves rose
higher than I have ever seen them ; and the constant visi-
bility of the disc of the sun in the bright, blue arch of hea-
ven, enabled me to measure the height of the waves by alti-
tudes of the sun taken upon the ridge of the wave and
in the trough, by a method which had not been tried at
that time. All Spanish, English65, and American voyagers
ascribe the above-described storms of the Southern Ocean
to the north-east trade-wind of the Atlantic.

In a new work*0 which I have undertaken with much

65 See Sir Edward Belcher, Voyage round the World, vol. i, p. 185.
According to my chronometric longitude I was in the Papagayo-storm
19° 11' to the west of the meridian of Guayaquil, and consequently
99° 9' west, and 880 miles west of the shore of Costa Rica.

66 My earliest work upon seventeen linear volcanoes of Guatemala
and Nicaragua is contained in the Geographical Journal of Berghaus
(Hertha, Bd. vi, 1826, pp. 131—161). Besides the old Chronista
Fuentes (lib. ix, cap. 9), I could then only make use of the important
work of Domingo Juarros, Compendia de la Historia de la Ciudad dc
Guatemala, and of the three maps by Galisteo (drawn in 1781, at the
command of the Mexican Viceroy, Matias de Galvez), by Jose' Rossi y
Rubi (Alcalde Mayor de Guatemala, 1800), and by Joaquin Ysasi and
Antonio de la Cerda (Alcalde de Granada) which I possessed princi-
pally in manuscript. In the French translation of his work upon the
Canary Islands, Leopold von Bnch has given a masterly extension of
my first sketch (Descr. Physique des Isles Canaries, 1836, pp. 500 — 514 ),
but the uncertainty of geographical synonyms and the confusion of
names caused thereby gave rise to many doubts, which have been for
the most part removed by the fine maps of Baily and Saunders; by
Molina's Bosquejo de la Republica de Costa Rica, and by the great and
very meritorious work of Squier (Nicaragua, its People and Monuments,

272 COSMOS.

assiduity, — partly from materials already published, and
partly from manuscript notes, — upon the linear volcanoes

•uith Tables of the Comparative Heights of the Mountains in Central
America, 1852, vol. i, p. 418, and vol. ii, p. 102). The important work
which is promised us by Dr. Oerstedt, under the title of Schildernng
der Naturverhdltnisse von Nicaragua und Costa Rica, besides the
admirable botanical and geological disco verieKS which constitute the
primary object of the undertaking, will also throw light upon the
geognostic nat-ure of Central America. Dr. Oersted passed through
that region in various directions from 1846 to 1848, and brought
back a collection of rocks to Copenhagen. I am indebted to his
friendly communications for interesting corrections of my fragmen-
tary work. From a careful comparison of the materials with which I
am acquainted, including those collected by Hesse, the Prussian
Consul-General in Central America, which are of great value, I bring
together the volcanoes of Central America in the following manner,
proceeding from south to north : —

Above the central plateau of Cartago (4648 feet), in the republic of
Costa Rica (lat. 10° 9') rise the three volcanoes of Turrialva, Irasu, and
Reventado, of which the first two are still ignited.

Volcan de Turrialva* (height about 11,000 feet) is, according to
Oersted, only separated from the Irasu by a deep, narrow ravine.
Its summit, from which columns of smoke rise, has not yet been
ascended.

The volcano Irasu*, also called the volcano of Cartago (11,100 feet)
to the north-east of the volcano Reventado, is the principal vent
of volcanic activity in Costa Rica, but still remarkably accessible,
and towards the south divided into terraces in such a manner that
one may on horseback, almost reach the elevated summit, from
which the two oceans, the sea of the Antilles and the Pacific, may be
geen at once. The cone of ashes and rapilli, which is about a thou-
sand feet in height, rises out of a wall of circumvallation (a crater of
elevation). In the flatter, north-eastern part of the summit, lies the
true crater, of 7500 feet in circumference, which has never emitted
lava-streams. Its eruptions of scoriae have often (1723, 1726, 1821,
1847) been accompanied by destructive earthquakes, the effect of
which has been felt from Nicaragua or Rivas to Panama (Oersted).
During a very recent ascent of the Irasu, in the beginning of May,
1855, by Dr. Carl Hoffmann, the crater of the summit and its
eruptive orifices have been more accurately investigated. The
altitude of the volcano is stated from a trigonometrical measure-
ment by Galindo, at 12,000 Spanish feet, or, taking the vara
ras£.=0.43 of a toise, at 11,000 feet. (Bonplandia, Jahrgang, 1856,
No. 3).

El Reventado (about 9500 feet), with a deep crater, of which the
southern margin has fallen in, and which was formerly filled with
water.

TRUE VOLCANOES. 273

of Central America, twenty-nine volcanoes are numbered,
whose former or present varied activity may be stated

The vol^.no Barba (more than 8419 feet), to the north of San
Jose*, the capital of Costa Rica; with a crater which contains
several small lakes.

Between the volcanoes Barba and Orosi, there follows a series of
volcanoes which intersects the principal chain, running S.E. — N.W.
in Costa Rica and Nicaragua, almost in the opposite direction, east and
west. Upon such a fissure stand, furthest to the eastward, Miravalles
and Tenorio (each of these volcanoes is about 4689 feet); in the centre,
to the south-east of Orosi, the volcano Rincon, also called Rincon de la
Vieja* (Squier, vol. ii, p. 102) which exhibits small eruptions of ashes
every spring at the commencement of the rainy season; and furthest to
the westward, near the little town of Alajuela, the volcano Votos*
(7513 feet) which abounds in sulphur. Dr. Oersted compares this
phenomenon of the direction of volcanic activity upon a transverse
fissure, with the east and west direction, which I found in the Mexican
volcanoes from sea to sea.

Orosi,* still active, in the most southern part of the State of Nica
ragua (5222 feet); probably the Volcan del Papayayo, on the chart of
the Deposito Hidrografico.

The two volcanoes, Mandeira and Ometepec* (4157 and 5222 feet)
upon a small island in the western part of the Laguna de Nicaragua,
named by the Aztec inhabitants of the district after these two moun-
tains (ome tepetl signifies two mountains ; see Buschmann, Aztekische
Ortsnamen, pp. 178 and 171). The insular volcano Ometepec, erro-
neously named Ometep by Juarros (Hist, de Guatemala, t. i, p. 51), is
still in activity. It is figured by Squier (vol. ii, p. 235).

The extinct crater of the island Zapatera, but little elevated
above the sea-level. The period of its ancient eruptions is quite
unknown.

The volcano of Momobacho, on the western shore of the Laguua de
Nicaragua, somewhat to the south of the city of Granada. As this city
is situated between the volcanoes of Momobacho (the place is also
called Mombacho, Oviedo, Nicaragua, ed. Ternaux, p. 245), and Masaya,
the pilots indicate sometimes the one and sometimes the other of
these conical mountains by the indefinite name of the Volcano of
Granada.

The volcano Massaya (Masaya) which has already been treated of in
detail (pp.258 — 261) was once a Stromboli, but has been extinct
since the great eruption of lava in 1670. According to the interesting
reports of Dr. Scherzer (Sitzungsberichtedcr Philos. Hist. Classe derAkad.
der Wiss. zu Wien, Bd. xx, s. 58) dense clouds of vapour were again
emitted in April, 1853, from a newly opened crater. The volcano of
Massaya is situated between the two lakes of Nicaragua and Managua
to the west of the city of Granada. Massaya is not synonymous with
Nindiri ; but, as Dr. Oersted expresses himself, Mcasaya and Nindiri*
VOL. V. T

274 COSMOS.

with certainty. The natives make the number more
than one-third greater, taking into account a quantity

form a twin volcano, with two summits and two distinct craters, both
of which have furnished lava-streams. The lava-stream of 1775 from
the Nindiri reached the lake of Managua. The equal height of these
two volcanoes, situated so close to each other, is stated at only 2450
feet.

Vokan de Momotombo* (7034 feet), burning, and often giving forth
a thundering noise, but without smoking, in lat. 12° 28', at the north"
ern extremity of the Laguna de Managua, opposite to the small island
Momotombito, so rich in sculptures (see the representation of Momo-
tombo in Squier, vol. i, pp. 233 and 302 — 312). The Laguna de
Managua lies 28 feet higher than the Laguna de Nicaragua, which
is more than double its size, and has no insular volcano.

From hence, to the Bay of Fonseca or Conchagua, at a distance of 23
miles from the coast of the Pacific, a line of six volcanoes runs from
S.E. to N.W.; closely approximated to each other and bearing the
common name of los Maribios (Squier, vol. i, p. 419; vol. ii, p. 123).

El Nuevo,* erroneously called Volcan de las Pttas, because the erup-
tion of the 12th April, 1850, took place at the foot of this mountain; a
great eruption of lava almost in the plain itself! (Squier, vol. ii,
pp. 105—110).

Volcan de Telica* visited, during its activity, by Oviedo as early as
the sixteenth century (about 1529), to the east of Chinendaga, near
Leon de Nicaragua, and consequently a little out of the direction
previously stated. This important volcano, which emits much sul-
phurous vapour from a crater 320 feet in depth, was ascended, a few
years since, by my scientific and talented friend Professor Julius
Frobel. He found the lava composed of glassy felspar and augite
(Squier, vol. ii, pp. 115 — 117). At the summit, at an elevation of
3517 feet, there is a crater, in which the vapours deposit great masses
of sulphur. At the foot of the volcano is a mud-spring (Salse ?).

The volcano el Viejo,* the northernmost of the crowded line of
six volcanoes. It was ascended and measured in the year 1838 by
Captain Sir Edward Belcher. The result of the measurement was
5559 feet. A more recent measurement, by Squier, gave 6002 feet.
This volcano, which was very active in Dampier's time, is still
burning. The fiery eruptions of scoriao are frequently seen in the city
of Leon.

The volcano Guanacaure, somewhat to the north, without the range
from el Nuevo to the Viejo, at a distance of only 14 miles from the
shore of the Bay of Fonseca.

The volcano Conseguina,* upon the cape which projects at the south-
ern extremity of the Bay of Fonseca (lat. 12° 50'), celebrated for the
fearful eruption, preceded by earthquakes, of the 23rd January, 1835.
The great darkue.ss during the fall of ashes, similar to that which haa

TRUE VOLCANOES. 275

of old eruptive basins, which were probably only lateral
eruptions on the declivity of one and the same mountain.

sometimes been caused by the volcano Pichincha, lasted for 43 hours.
At a distance of a few feet, firebrands could not be perceived. Respi-
ration was obstructed, and a subterranean noise, like the discharge of
heavy artillery, was heard not only in Balize on the peninsula of
Yucatan, but also upon the coast of Jamaica, and upon the plateau of
Bogota", in the latter case at an elevation of more than 8500 feet above
the sea, and at a distance of nearly five hundred and sixty geographical
miles (Juan Galindo, in Silliman's American Journal, vol. xxviii, 1835,
pp. 332—336 ; Acosta, Viajes a los Andes, 1849, p. 56, and Squier,
vol. ii, pp. 110 — 113; figures pp. 163 and 165). Darwin (Journal of
Researches during the Voyage of the Beagle, 1845, p. 291) calls attention
to a remarkable coincidence of phenomena : — After a long slumber,
Conseguiua, in Central America, and Aconcagua and Corcovado
(S. lat. 32f° and 43^°) in Chili, broke out on the same day (acci-
dentally ?).

Volcano of Conchagua, or of Amalapa, at the north of the entrance
to the Bay of Fonseca, opposite to the volcano Conseguina, near the
beautiful Puerto de la Union, the harbour of the neighbouring town of
San Miguel.

From the state of Costa Rica to the volcano of Conchagua, there-
fore, the close series of twenty volcanoes follows a direction from S.E. to
N.W., but on entering near Conchagua into the State of San Salvador
which, in the short distance of 160 geog. miles exhibits five still more
or less active volcanoes, the line, like the Pacific coast itself, turns more
E.S.E. — W.N.W., and indeed almost E. — W , whilst on the eastern,
Caribbean coast (towards the Cape Gracias a" Dios) the land suddenly
bulges out in Honduras and los Mosquitos (see above, p. 269). It is
only, as tlere remarked, to the north of the high volcanoes of Old
Guatemala, towards the Laguua de Atitlan, that the former general
direction N. 45° W. again occurs, until at last, in Chiapa, and on the
isthmus of Tehuantepec, the abnormal direction E. — W. is again mani-
fested, but in non-volcanic chains. Besides Conchagua, the following
four volcanoes belong to the State of San Salvador : —

The volcano of San Miguel Bosotlan* (lat. 13° 35'), near the town of
the same name, the most beautiful and regular of trachytic cones
next to the insular volcano Ometepec, in the lake of Nicaragua,
(Squier, vol. ii, p. 196). The volcanic forces are very active in
Bosotlan, in which a great eruption of lava occurred on the 20th of
July, 1844.

Volcano of San Vicente,* to the west of the Rio de Lempa, between
the towns of Sacatecoluca and Sacatelepe. A great eniption of ashes
took place, according to Juarros, in 1643 ; and in January, 1835, a
long continued eruption occurred with destructive earthquakes.

Volcano of San Salvador (lat. 13° 470, near the city of the eame

T 2

276 COSMOS.

Amongst the isolated conical and bell-shaped mountains,
which are there called volcanoes, many may, indeed, consist

name. The last eruption was that of 1656. The whole surrounding
country is exposed to violent earthquakes ; that of the 16th of April,
1854, which was preceded by no noises, overthrew nearly all the
buildings in San Salvador.

Volcano of Izalco,* near the village of the same name, often pro-
ducing ammonia. The first eruption recorded in history occurred
on the 23rd February, 1770; the last widely-luminous eruptions were
in April, 1798, 1805 to 1807, and 1825 (see above, p. 261, and Thomp-
son, Official Visit to Guatemala, 1829, p. 512).

Volcan de Pacaya* (lat. 14° 23'), about 14 miles to the south-east
of the city of New Guatemala, on the small Alpine lake Amatitlan, a
very active and often flaming volcano ; an extended ridge with three
domes. The great eruptions of 1565, 1651, 1671, 1677, and 1775 are
known ; the last, which produced much lava, is described by Juarros
as an eye-witness.

Next follow the two volcanoes of Old Guatemala, with the sin-
gular appellations de Agua and de Fuego, near the coast, in latitude
14° 12'.

Volcan de Agua, a trachytic cone near Escuintla, higher than the
Peak of Teneriffe, surrounded by masses of obsidian (indications of old
eruptions?). The volcano, which reaches into the region of perpetual
snow, has received its name from the circumstance that, in September,
1541, a great inundation (caused by earthquake and the melting of
snow?) was ascribed to it; this destroyed the first established city of
Guatemala, and led to the building of the second city, situated to the
north-north-west, and now called Antigua Guatemala.

Volcan de Fuego,* near Acatenango, 23 miles in a west-north-west
direction from the so-called water-volcano. With regard to their rela-
tive position, see the rare map of the Alcalde Mayor, Don Jose Rossi y
Rubi, engraved in Guatemala, and sent to me thence as a present :
Bosquejo del espacio que media, entre los estremos de la Provincia de
Sucliitepeques y la Capital de Guatemala, 1800. The Volcan de Fuego
is still active, but now much less so than formerly. The older great
eruptions were those of 1581, 1586, 1623, 1705, 1710, 1717,1732, 1737,
and 1799, but it was not only these eruptions, but also the destruc-
tive earthquakes which accompanied them, that moved the Spanish
Government in the second half of the last century to quit the second
seat of the city (where the ruins of la Antigua Guatemala now stand),
and compel the inhabitants to settle further to the north, in the new
city of Santiago de Guatemala. In this case, as at the removal of
Riobamba, and several other towns near the volcanoes of the chain of
the Andes, a dogmatic and vehement dispute was carried on in reference
to the difficult selection of a locality " of which it might be asserted,
t. ^cording to previous experience, that it was but little exposed to the
action of neighbouring volcanoes (lava-streams, eruptions of scoriae and

TRUE VOLCANOES. 277

of trachyte and dolerite, but having always been unopened,
have never exhibited any ign« ous activity since the time of
their upheaval. Eighteen are to be regarded as still active ;
seven of these have thrown up flames, scoria3 and lava-
streams in the present century (1825, 1835, 1848, and
1850); and two* at the end of the last century (1775 and
1799). The deficiency of lava-streams in the mighty vol-
canoes of the Cordilleras of Quito has recently given occa-
sion to the repeated assertion that this deficiency is equally
general in the volca.roes of Central America. Certainly,
in the majority of cases, eruptions of scoriae and ashes have
been unaccompanied by any effusion of lava — as for exam-
earthquakes !)" In 1852, during a great eruption, the Volcan de Fuego
poured forth a lava-stream towards the shore of the Pacific. Captain
Basil Hall measured, under sail, both the volcanoes of Old Guatemala,
and found for the Volcan de Fuego 14,666 feet, and for the Volcan de
Agua, 14,903 feet. The foundation of this measurement has been
tested by Poggendorff. He found the mean elevation of the two moun-
tains to be less, and reduced it to about 13,109 feet.

Volcan de Quesaltenango* (lat. 15° 10'), burning since 1821, and
smoking, near the town of the same name ; the three conical moun-
tains which bound the Alpine lake Atitlan (in the mountain chain of
Solola) on the south, are also said to be ignited. The volcano of
Tajamulco, referred to by Juarros, certainly cannot be identical with
the volcano of Quesaltenango, as the latter is at a distance of 40 geog.
miles to the N.W., of the village of Tajamulco, to the south of Tejutla.

What are the two volcanoes of Sacatepeques and Sapotitlan, men-
tioned by Funel, or Brue"s Volcan de Amilpas?

The great volcano of Soconusco, situated on the borders of Chiapa,
28 geog. miles to the south of Ciudad Real, in lat. 16° 2'.

At the close of this long note I think I must again mention that the
barometric determinations of altitude here adduced are partly derived
from Espinache, and partly borrowed from the writings and maps of
Baily, Squier, and Molina.

w The following 18 volcanoes, constituting therefore nearly the half
of all those referred to by me as active in former or present times, are
to be regarded as at present more or less active : — Irasu and Turrialva,
near Cartago, el Rincon de la Vieja, Votos(?) and Orosi; the insular vol-
cano Ometepec,Nindiri, Momotomba, el Nuevo, at the foot of the trachytic
mountain Las Pilas, Telica, el Viejo, Conseguina, San Miguel Bosotlan,
.San Vicente, Izalco, Pacaya, Volcan de Fuego (de Guatemala), and
Quesaltenango. The most recent eruptions are those of el Nuevo, near
las Pilas, on the 18th April, 1850 ; San Miguel Bosotlan, 1848; Conse-
guina, and San Vicente, 1835; Izalco, 1825; Volcan de Fuego, neajf
New Guatemala, 1799 and 1852; and Pacaya, 1775.

278 COSMOS.

pie, at present in the volcano of Izalco ; but the descrip-
tions which have been given by eye-witnesses of the lava-
producing eruptions of the four volcanoes, Nindiri, el Nuevo,
Conseguina, and San Miguel de Bosotlan, give an opposite
testimony68.

I have purposely dwelt at length upon the details of the
position and close approximation of the linear volcanoes of
Central America, in the hope that some day a geogaosist,
who has previously given a profound study to the active
volcanoes of Europe, and the extinct ones of Auvergne,
the Vivarais or the Eifel, and who also (this is of the
greatest importance) knows how to describe the mineral-
ogical composition of the different rocks in accordance
with the present state of our knowledge, may feel himself
impelled to visit this region, which is so near and so
accessible. Even if the traveller should devote himself
exclusively to geognostic investigations, there still remains
much to be done here, — especially the oryctognostic deter-
mination of the trachytic, doleritic, and melaphyric rocks ;
the separation of the primitive mass upheaved, and of the
portion of the elevated mass which has been covered over
by subsequent eruptions ; the seeking out and recognition
of true, slender, uninterrupted lava-streams, which are only
too frequently confounded with accumulations of erupted
scoriae. Conical mountains, which have never been opened,
rising in a dome or bell-like form, such as Chimborazo, are
therefore to be clearly separated from volcanoes which have
been, or still are, active, throwing out scoriae and lava-
streams, like Vesuvius and Etna, or scoriae and ashes alone,
like Pichincha or Cotopaxi. I know nothing that promises
to impart a more brilliant impetus to our knowledge of vol-
canic activity, which is still very deficient in multiplicity
of observations in large and connected continental districts.
As the material results of such a labour, collections of
rocks would be brought home from many isolated, true vol-

68 Compare Squier, Nicaragua, vol. ii, p. 103, with pp. 106 and 111,
as also his previous small \vork On the Volcanoes of Central America,
1850, p. 7; Leopold de Buch, lies Canaries, p. 506, where reference
is made to the lava-stream which broke out of the volcano Nindiri in
1775, and which has been recently again seen by a very scientific ob-
server, Dr. Oersted,

TRUE VOLCANOES. 279

canoes, and unopened trachytic cones, together with the
non-volcanic masses which have been broken through by
both ; the subsequent chemical analyses, and the chemico-
geological inferences deduced from the analyses, would open
a field equally wide and fertile. Central America and Java
have the unmistakeable superiority over Mexico, Quito, and
Chili, that in a greater space they exhibit the most variously
formed and most closely approximated stages of volcanic
activity.

At the point where the characteristic series of the vol-
canoes of Central America terminates on the borders of
Chiapa with the volcano of Soconusco (lat. 16° 2'), there
commences a perfectly different system of volcanoes — the
Mexican. The isthmus of Huasacualco and Tehuantepec,
so important for the trade with the coast of the Pacific,
like the state of Oaxaca, situated to the north-west, is en-
tirely without volcanoes, and, perhaps, even destitute of un-
opened trachytic cones. It is only at a distance of 160 geog.
miles from the volcano of Soconusco, that the small volcano of
Tuxtla rises near the coast of AJvarado (lat. 18° 28'). Situated
on the eastern slope of the Sierra de San Martin, it had a
great eruption of flames and ashes on the 2nd of March, 1793.
An exact astronomical determination of the position of the
colossal snowy mountains and volcanoes in the interior of
Mexico (the old Anahuac) led me, after my return to
Europe, while inserting the maxima of elevations in my
chart of New Spain, to the exceedingly remarkable result,
that there is in this place, from sea to sea, a parallel of the
volcanoes and greatest elevations which oscillates by only
a few minutes to and from the parallel of 19°. The only
volcanoes and, at the same time, the only mountains covered
with perpetual snow in the country, and consequently ele-
vations varying from 12,000 to 3,000 feet, — the volcanoes
of Orizaba, Popocatepetl, Toluca, and Colima, — lie between
the latitudes of 18° 59' and 19° 20', and thus indicate the
direction of a fissure of volcanic activity of 360 geog. miles
in length69. In the same direction (lat. 19° 9'), between the

69 See all the bases of these Mexican local determinations, and
their comparison with the observations of Don Joaquin Ferrer, in my
Recueil d Observations Astron. vol. ii, pp. 521, 529, and 536 — 550, and
£gsai Politique sur la Nourelle-Espagne, t. i, pp. 55 — 59, and 176, t. ii.

280 COSMOS.

volcanoes of Toluca and Colima, at a distance of 116 and
128 geog. miles from them, the new volcano of Jorullo (4265
feet) rose on the 14th September, 1759, in a broad plain,
having an elevation of 2583 feet. The local position of this
phenomenon in relation to the situation of the other Mexican
volcanoes, and the circumstance that the fissure from east
to west which I here indicate intersects the direction of
the great mountain chain striking from south-south-east to
north-north-west almost at right angles, are geological
phenomena no less important than the distance of the
eruption of Jorullo from the seas, the evidences of its up-
heaval which I have represented graphically in detail, the
innumerable fuming hornitos which surround the volcano,
and the fragments of granite, which I found immersed in
the lava poured forth from the principal volcano of Jorullo,
in a district which is destitute of granite for a long dis-
tance.

The following table contains the special local determina-
tions and elevations of the series of volcanoes of Ana-
huac, upon a fissure which, running from sea to sea, inter-
sects the fissure of elevation of the great range of moun-
tains : —

p. 173. I had myself early raised doubts with regard to the astrono-
mical determination of the position of the volcano of Colima, near the
coast of the Pacific (Essai Polit. t. i, p. 68, t. ii, p. 180). According to
angles of altitude taken by Captain Basil Hall while under sail, the
volcano is situated in lat. 19° 36', and consequently half a degree further
north than I concluded to be its position from Itineraries ; certainly
without absolute determinations for Selagua and Petatlan, upon which
I depended. The latitude, 19° 25', which I have given in the text, is,
like the determination of altitude (12,005 feet), from Captain Beechey
( Voyage, pt. ii, p. 587). The most recent map by Laurie (The Mexican
and Central States of America, 1853) gives 19° 20' for the latitude.
The latitude of Jorullo may also be wrong by 2 — 3 minutes, as I was
then occupied entirely with geological and topographical investigations,
and neither the sun nor stars were visible for determinations of latitude.
(See Basil Hall, Journal written on the Coast of Chili, Peru, and Mexico,
1824, vol. ii, p. 379; Beechey, Voyage, pt. ii, p. 587; and Humbolclt,
Essai Polit. t. i, p. 68, t. ii, p. 180). In the true and exceedingly
artistic views of the volcano of Colima, drawn by Moritz Kugendas,
which are preserved in the Berlin Museum, we distinguish two adjacent
mountains, — the true volcano, which constantly emits smoke, and is
covered with but little snow, and the more elevated Nevada, which
rises far into the region of perpetual snow.

TRUE VOLCANOES.

281

Sequence from E. to W.

Latitude.

Elevation
above the sea
in feet.

Volcano of Orizaba. . . .
Nevado Tztaccihuatl . .
Volcano Popocatepetl . .
Volcano of Toluca ....
Volcano of Jorallo ....
Volcano of Colima ....

19° 2' 17"
19 10 3
18 59 47
19 11 33
19 9 0
19 20 0

17,879
15705
17726
15168
4265
12005

The prolongation of the parallel of volcanic activity in
the tropical zone of Mexico, leads, at a distance of 506
miles westward from the shores of the Pacific to the insular
group Revillagigedo, in the vicinity of which Collnet saw
pumice-stone floating, and perhaps still farther on, at a dis-
tance of 3360 geog. miles to the great volcano Mauna Roa
(19° 28'), without causing any upheaval of islands in the
intervening space !

The group of linear volcanoes of Quito and New Granada
includes a volcanic zone which extends from 2° S. lat. to
nearly 5° N. lat. The extreme boundaries of the area in
which the reaction of the interior of the earth upon its sur-
face is now manifested, are the uninterruptedly active San-
gay, and the Paramo and Volcan de Ruiz, the most recent
conflagration of which was in the year 1829, and which was
seen smoking by Carl Degenhardt from the Mina de San-
tana in the province of Mariquita in 1831 and from Mar-
mato in 1833. The most remarkable traces of great erup-
tive phenomena next to the Ruiz, are exhibited from north
to south, by the truncated cone of the volcano of Tolima
(18,129 feet), celebrated by the recollection of the destruc-
tive eruption of the 12th March, 1595 ; the volcanoes of
Purace" (17,006 feet) and Sotara near Popayan ; that of
Pasto (13,450 feet), near the city of the same name; of
the Monte de Azufre (12,821 feet), near Tuquerres ; of
Cumbal (15,618 feet), and of Chiles, in the province do los
Pastos ; then follow the historically celebrated volcanoes of
the true high land of Quito, to the south of the equator, of
which four, — namely, Pichincha, Cotopaxi, Tungu rah.ua, and

282 cosuos.

Sangay, — certainly cannot be regarded as extinct volcanoes.
Although to the north of the mountain group of the
Robles, near Popayan, as we shall shortly more fully show
in the tripartition of the vast chain of the Andes, it
is only the central Cordillera, and not the western one,
nearer to the sea-coast, that exhibits a volcanic activity ;
on the other hand, to the south of this group, where the
Andes form only two parallel chains, so frequently men-
tioned by Bouguer and La Condamine in their writings,
volcanoes are so equally distributed, that the four volcanoes
of the Pastes, as well as Cotocachi, Pichincha, Iliniza, Car-
guairazo, and Yana-Urcu, at the foot of Chimborazo, have
broken out upon the western chain, nearest to the sea ; and
upon the eastern Cordillera, Imbabura, Cayambe, Antisana,
Cotopaxi, Tungurahua (opposite to Chimborazo towards the
east, but still nearly approximated to the middle of the
narrow elevated plateau), the Altar de los Col lanes (Capac-
Urcu), and Sangay. If we include the northernmost group
of the linear volcanoes of South America in one view, the
opinion so often expressed in Quito, and to a certain extent
founded on historical documents, of the migration of the
volcanic activity and increase of intensity from north to
south, acquires, at all events, a certain amount of proba-
bility. It is true that in the south, and indeed close to the
colossal Sangay, which acts like Stromboli, we find the ruins
of the " Prince of Mountains," Capac-Urcu, which is said
to have exceeded Chimborazo in height, but which fell in
and became extinct in the latter part of the fifteenth cen-
tury (fourteen years before the capture of Quito by the son
of the Inca Tupac Yupangui), and has never again resumed
its former activity.

The space of the chain of the Andes which is not occupied
by groups of volcanoes is far greater than is usually sup-
posed. In the northern part of South America, from the
volcan de E-uiz and the conical mountain Tolima, the two
most northern volcanoes of the series of New Granada and
Quito, over the isthmus of Panama as far as the vicinity
of Costa Rica, where the series of volcanoes of Central
America commences, there is a country which is frequently
and violently convulsed by earthquakes, and in which
flaming salses, but no true volcanic eruptions, are knovm.

TRUE VOLCANOES 283

The length of this tract amounts to 628 geog. miles. Nearly-
double this length (occupying a space of 968 geog. miles) is
a tract of country free from volcanoes, from the Sangay, the
southern termination of the group of New Granada and
Quito, to the Chacani, near Arequipa, the commencement of
the series of volcanoes of Peru and Bolivia. So compli-
cated and various in the same mountain chain, must have
been the coincidence of the conditions upon which depend
the formation of permanently open fissures, and the unim-
peded communication of the molten interior of the earth
with the atmosphere. Between the groups of trachytic and
doleritic rocks, through which the volcanic forces become
active, lie rather shorter spaces, in which prevail granite,
syenite, mica-schists, clay-slates, quartzose porphyries, sili-
cious conglomerates, and limestones, of which (according to
Leopold von Buch's investigation of the organic remains
brought home by Degenhardt and myself), a considerable
portion belong to the chalk formation. The gradually in-
creased frequency of labradoritic rocks, rich in pyroxene
and oligoclase, announces to the observant traveller (as I
have already elsewhere shown) the transition of a zone
hitherto closed and non-volcanic, and often very rich in
silver in porphyries, destitute of quartz and full of glassy
felspar, into the volcanic regions, which still freely commu-
nicate with the interior of the earth.

The more accurate knowledge which we have recently
attained of the position and boundaries of the five groups
of volcanoes (the groups of Anahuac or tropical Mexico,
of Central America, of New Granada, and Quito, of Peru
and Bolivia, and of Chili) shows that, in the part of the
Cordilleras which extends from 19^° north, to 46° south
latitude, (and, consequently, taking into account the curves
caused by alterations in the axial direction, for a distance
of nearly 5000 geog. miles,) not much70 more than half

70 The following is the result of the determination of the length and
latitude of the five groups of linear volcanoes in the chain of the Andes,
as also the statement of the distance of the groups from each other :
a statement illustrating the relative proportions of the volcanic and
non-volcanic areas.

I. Group of the Mexican Volcanoes: The fissure upon which the
volcanoes have broken out is directed from east to west, frou?

284 k COSMOS.

(calculation gives 2540 against 2428 geog. miles) is occupied
, by volcanoes. If we examine the distribution of the space

the Orizaba to the Colima, for a distance of 392 geog. miles, be-
tween latitudes 19° and 19° 20'. The Volcano of Tuxtla lies
isolated 128 miles to the east of Orizaba, near the coast of
the Gulf of Mexico, and in a parallel (18° 28') which is half a
degree further south.

II. Distance of the Mexican group from the next group, that of
Central America (from the volcano of Orizaba to the volcano of
Soconusco, in the direction E.S.E.— W.N.W.) 300 miles.

III. Group of the Volcanoes of Central America : Its length from S.E.
to N.W., from the volcano of Soconusco to Turrialva, in Costa
Rica, more than 680 miles.

IV. Distance of the group of Central America from the series of
volcanoes of New Granada and Quito, 628 miles.

V. Group of the Volcanoes of New Granada and Quito : Its length
from the eruption in the Paramo de Ruiz to the north of the
Volcan de Tolima, to the volcano of Sangay, 472 miles. The
portion of the chain of the Andes between the volcano of Purac6,
near Popayan, and the southern part of the volcanic mountain
group of Pasto is directed N.N.E.— S.S.W. Far to the eastward
from the volcanoes of Popayan, at the sources of the Rio Fragua,
there is a very isolated volcano, which I have inserted upon my
general map of the mountain group of the South American
Cordilleras, from the statements of missionaries from Timana,
which were communicated to me : distance from the sea-shore,
152 miles.

VI. Distance of the volcanic group of New Granada and Quito, from
the group of Peru and Bolivia, 960 miles, the greatest length
destitute of volcanoes.

VII. Group of the Series of Volcanoes of Peru and Bolivia, from the
Volcan de Chacani and Arequipa to the volcano of Atacama
(16i°— 21-1°) 420 miles.

VIII. Distance of the group of Peru and Bolivia from the volcanic
group of Chili, 540 geog. miles. From the portion of the desert of
Atacama, on the border of which the volcano of San Pedro rises,
to far beyond Copiapo, even to the volcano of Coquimbo (30° 5'),
in the long Cordillera to the west of the two provinces Catamarca
and Rioja,there is no volcanic cone.

IX. Group of Chili, from the volcano of Coquimbo to the volcano
San Clemente, 968 miles.

These estimates of the length of the Cordilleras, with the curvature
which results from the change in the direction of the axis, from the pa-
rallel of the Mexican volcanoes in 1 9^° of north latitude, to the volcano of
San Clemente in Chili (46° 8' S. lat.), give for a distance of 4968 miles,
a space of 2540 miles which is covered by five linear groups of volcanoes

TRtTE VOLCANOES.

285

free from volcanoes between the five volcanic groups, we
find the maximum distance of two groups from one another
between the volcanic series of Quito and Peru. This is
fully 960 miles, whilst the most closely approximated
groups are the first and second, those of Mexico and Cen-
tral America. The four interspaces between the five groups
are severally 300, 628, 960, and 540 miles. The great dis-
tance of the southernmost volcano of Quito from the most
northern of Peru, is, at the first glance, the more remark-
able, because, according to old custom, we usually term the
measurement of degrees upon the high land of Quito, the
Peruvian measure-meat. Only a small southern portion of
the Peruvian chain of the Andes is volcanic. The number
of volcanoes, according to the lists which I have prepared
after a careful criticism or the newest materials, is as fol-
lows : —

Names of the five groups of linear Vol-
canoes of the New Continent, from
19° 25' north, to 46° 8' south
latitude.

No. of Volca-
noes included
in each group.

No. of Volca-
noes which are
to be regarded
as still ignited.

G^oup of Mexico'1

6

4

Group of Central America73 ....
Group of New Granada and )
Quito73 J

29

18

18
10

Group of Peru and Bolivia74. . . .
Group of Chili74

14

24

3
13

(Mexico, Central America, New Granada with Quito, Peru with Bolivia,
and Chili); and a space probably quite free from volcanoes of 2428
miles. The two spaces are nearly equal. I have given very definite
numerical relations, as obtained by the careful criticism of my own
maps and those of others, in order to give rise to a greater desire to
improve them. The longest portion of the Cordilleras free from vol-
canoes is that between the groups of New Granada with Quito and
Peru with Bolivia. It is accidentally equal to that occupied by the
volcanoes of Chili.

71 The group of volcanoes of Mexico includes the volcanoes of
Orizaba,* Popocatepetl,* Toluca (or Cerro de San Miguel de Tutucuitla-
pilco), Jorullo,* Coliina,* and Tuxtla.* Here, as in similar lists, the
still active volcanoes are indicated by asterisks.

286 COSMOS.

According to these data the total number of volcanoes in
the five American groups is 91, of which 56 belong to the

72 The series of volcanoes of Central America is enumerated iu the
notes 66 and 67.

73 The group of New Granada and Quito includes the Paramo y
Volcan de Ruiz,* the volcanoes of Tolima, Purace",* and Sotara", near
Popayan ; the Volcan del Bio Fragua, an affluent of the Caqueta ; the
volcanoes of Paste, el Azufral,* Cumbal,* Tuquerres,* Chiles, Imba-
buru, Cotocachi, Rucu-Pichincha, Antisana(?), Cotopaxi,* Tungurahua,*
Capac-Urcu, or Altar de los Collanes(?), and Sangay.*

74 The group of Southern Peru and Bolivia, includes from north to
south the following 14 volcanoes : —

Volcano of Chacani (also called Charcani, according to Curzon and
Meyen), belonging to the group of Arequipa and visible from the
town ; it is situated on the right bank of the Rio Quilca, in
lat. 16° 11', according to Pentland, the most accurate geological
observer of this region, 32 miles to the south of the Nevado de
Chuquibamba, which is estimated at more than 19,000 feet in
height. Manuscript records in my possession give the volcano of
Chacani a height of fully 19,601 feet. Curzon saw a large crater
in the south-eastern part of the summit.

Volcano of Arequipa* lat. 16° 20', 12 miles to the north-east
of the town. With regard to its height (18,879 feet?) see p. 252.
Thaddaus Hanke, the botanist of the expedition of Malaspina
(1796), Samuel Curzon from the United States of North America
(1811) and Dr. Weddell (1847) have ascended the summit. In
August, 1831, Meyen saw large columns of smoke rising; a year
previously the volcano had thrown out scorise, but never lava-
streams (Meyen' s Reise um die Erde, Th. ii, s. 33).

Volcan de Omato, lat. 16° 50'; it had a violent eruption in the year
1667.

Volcan de Uvillas or Uvinas, to the south of Apo ; its last eruptions
were in the sixteenth century.

Volcan de Pichu-PicJiu, 16 miles to the east of the town of
Arequipa (lat. 16° 25'), not far from the Pass of Cangallo, 9673 feet
above the sea.

Volcan Viejo, lat 16° 55', an enormous crater, with lava-streams and
much pumice-stone.

The six volcanoes just mentioned, constitute the group of Are-
quipa.

Volcan de Tacora or Chipicani, according to Pentland's fine map of
the lake of Titicaca, lat. 17° 45', height 19,738 feet.

Volcan de Bahama* 22,354 leet in height, lat. 18° 7'; a truncated
cone of the most regular foim ; see p. 253. The volcano of
Sahama is (according to Pentland) 927 feet higher than tha

TRUE VOLCANOES. 287

continent of Soutli America. I reckon as volcanoes, besides
those which are still burning and active, those volcanic

Chimborazo, but 6650 feet lower than Mount Everest in the
Himalaya, which is now regarded as the highest peak of Asia.
According to the last official report of Colonel Waugh, of the
1st March, 1856, the four highest mountains of the Himalayan
chain are : — Mount Everest (Gaurischanka) to the north-east of
Katmandu, 29,000 feet, — the Kuntschinjinga, to the north of
Darjiling, 28,154 feet,— the Dhaulagiri (Dhavalagirir), 26,825 feet,
and Tschumalari (Chamalari), 23,946 feet.

Volcano of Pomarape, 21,699 feet, lat. 18° 8', almost a twin moun-
tain with the following volcano.

Volcano of Parinacota, 22,029 feet, lat. 18° 12'.

The group of the four trachytic cones Sahama, Pomarape, Parinacota,
and Gualatieri, lying between the parallels of 18° 7' and 18° 25', is,
according to Pentland's trigonometric measurement, higher than Chim-
borazo, or more than 21,422 feet.

Volcano of Gualatieri,* 21,962 feet, lat. 18° 25', in the Bolivian
province Carangas; very active, according to Pentland (Hertha,
Bd. xiii, 1829, s. 21).

Not far from the Bahama-group, 18° 7' to 18° 25', the series of
volcanoes and the entire chain of the Andes, which lies to the westward
of it, suddenly change their strike, and pass from the direction
S.E. — N.W. into that from north to south, which becomes general as
far as the Straits of Magellan. I have treated of this important turning
point, the notch in the shore near Arica (18° 280 which has an analogue
on the west coast of Africa in the Gulf of Biafra, in the first volume of
Cosmos, p. 296.

Volcano of Isluga, lat. 19° 20', in the province of Tarapaca, to the
west of Carangas.

Volcan de San Pedro de Atacama, on the north-eastern border of the
Desierto of the same name, in lat. 22° 16', according to the new
plan of the arid sandy desert (Desierto) of Atacama, by Dr.
Philippi, 16 miles to the north-east of the small town of San Pedro,
not far from the great Nevado de Chorolque.

There is no volcano from 204° to 30°, and after an interruption of
more than 568 miles, the volcanic activity first reappears in the
volcano of Coquimbo. For the existence of a volcano of Copiapo
(lat. 27° 28') is denied by Meyen, whilst it is asserted by Philippi,
who is well acquainted with the country.

75 Our geographical and geological knowledge of the group of vol-
canoes, which we include in the common name of the linear volcanoes
of Chili, is indebted for the first incitement to its completion, and
even for the completion itself, to the acute investigations of Captain

288 COSMOS.

formations whose old eruptions belong to historic periods,
or of which the structure and eruptive masses (craters of

Fitzroy in the memorable expedition of the ships Adventure and
Beagle, and to the ingenious and more detailed labours of Charles
Darwin. The latter, with his peculiar generalizing view, has grasped
the connexion of the phenomena of earthquakes and eruptions of
volcanoes under one point of view. The great natural phenomenon
which destroyed the town of Copiapo on the 22nd of November, 1822,
was accompanied by the upheaval of a considerable tract of country
on the coast ; and during the exactly similar phenomenon of the 20th
February, 1835, which did so much injury to the city of Concepcion,
a submarine volcano broke out with fiery eruptions near the shore of
the island of Chiloe, near Bacalao Head, and raged for a day and a half.
All this, depending upon similar conditions, has also occurred formerly,
aud strengthens the belief that the series of rocky islands which lies
opposite to the Fjords of the mainland to the south of Valdivia and
of the Fuerte Maullin, and includes Chiloe, the Archipelago of Chonos
and Huaytecas, the Peninsula de Tres Monies, and the Islas de la
Campana, de la Madre de Dios, de Santa Lucia and los Lobos, from
39° 53' to the entrance of the Straits of Magellan, is the crest of a
submerged western Cordillera projecting above the sea. It is true that
no open trachytic cone, no volcano, belongs to these fractis excequore
terris, but individual submarine eruptions, sometimes followed and
sometimes preceded by mighty earthquakes, appear to indicate
the existence of this western fissure (Darwin, On the connexion of
volcanic phenomena, the formation of mountain chains, and the effect of
the same powers, by which continents are elevated : in the Trans. Geol.
Society, 2nd series, vol. v, pt. 3, 1840, pp 606 — 615, and 629—631 ;
Humboldt, Essai Politique sur la Nouvelle Espagne, t. i. p. 190, and
t. ii. p. 287).

The series of 24 volcanoes included in the group of Chili is as
follows, counting from north to south, from the parallel of Coquimbo
to 46° S. lat. :—

(a.) Between the parallels of Coquimbo and Valparaiso : —

Volcan de Coquimbo (lat. 30° 5') ; Meyen, th. i. s. 385.

Volcano of Limari.

Volcano of Chuapri.

Volcano of Aconcagua*, W.N",W., of Mendoza, lat. 32° 39'; altitude
23,004 feet, according to Kellet (See p. 253, note), but according
to the most recent trigonometric measurement of the engineer
Amado Pissis (1854), only 22,301 feet; consequently, rather lower
than the Sahama, which Pentland now assumes to be 22,350 feet
(Gillis, U.S. Naval Astron. Exped. to Chili, vol. i. p. 13). The
geodetic basis of measurement of Aconcagua at 6797 metres, which
required eight triangles, has been developed by M. Pissis, in the
Anales de la Universidad de Chile, 1852, p. 219.

TRUE VOLCANOES. 289

elevation and eruption, lavas, scoriae, pumice-stones and
obsidians) characterise them, without reference to any tra-

The Peak of Tupungato is stated by Gilliss to be 22,450 English, or
21,063 Paris, feet in height, and in lat. 33° 22' ; but in the map
of the province of Santiago by Pissis (Gilliss, p. 45), it is estimated
at 22,016 English, or 20,655 Paris, feet. The latter number is re-
tained (as 6710 metres) by Pissis in the Anales de Chile, 1850,
p. 12.

(b.) Between the parallels of Valparaiso and Conception :
Volcano of Maypu*, according to Gilliss (vol.i, p. 13), in lat. 34° 17',
(but in his general map of Chili, 33° 47', certainly erroneously),
and 17,662 feet in height. Ascended by Meyen. The trachytic
rock of the summit has broken through upper Jurassic strata, in
which Leopold von Buch detected Exogyra Couloni, Trigonia cos-
tata and Ammonites biplex from elevations of 9600 feet (Descrip-
tion Physique des lies Canaries, 1836, p. 471). No lava streams,
but eruptions of flame and scoriae from the crater.
Volcano of Peteroa*, to the east of Talca, in lat. 34° 53' ; a volcano
which is frequently in activity, and which, according to Molina's
description, had a great eruption on the 3rd December, 1762. It
was visited in 1831 by the highly-gifted naturalist, Gay.

Volcan de Chilian, lat. 36° 2' ; a region which has been described by
the missionary Havestadt of Minister. In its vicinity is situated
the Nevado Descabezado (35° 1'), which was ascended by Domeyko,
and which Molina declared (erroneously) to be the highest moun-
tain of Chili. Its height has been estimated by Gilliss at 13,100
feet (U.S. Naval Astr. Exped., 1855, vol. i. pp. 16 and 371).

Volcano of Tucapel, to the west of the city of Concepcion ; also
called Sill a Veluda ; perhaps an unopened trachytic mountain,
which is in connection with the active volcano of Antuco.

(c) Between the parallels of Conception and Valdima :
Volcano of Antuco*, lat. 37° 7'; geognostically described in detail by
Poppig; a basaltic crater of elevation, from the interior of
which a trachytic cone ascends, with lava-streams, which break
out at the foot of the cone, and more rarely from the crater at the
summit (Poppig, Reise in Chile and Peru, Bd. i. s. 364). One of
these streams was still flowing in the year 1828. The indefatig-
able Domeyko found the volcano in full activity in 1845, and its
height only 8920 feet (Pentland, in Mary Somerville's Physical
Geography, vol. i. p. 186). Gilliss states the height at 9242 feet,
and mentions new eruptions in the year 1853. According to
intelligence communicated to me by the distinguished American
astronomer, Gilliss, a new volcano rose out of the depths in the
interior of the Cordillera between Antuco and the Descabezado
on the 25th of November, 1847, forming a hill* of 320 feet. The
sulphureous and fiery eruptions were seen for more than a year
VOL. V. U

290 COSMOS.

dition, as volcanoes which have long been extinct. Unopened
trachytic cones and domes, or unopened long trai-hytic ridges,
such as Chimborazo and Iztaccihuatl, are excluded. This is
also the sense given to the word volcano by Leopold von
Buch, Charles Darwin, and Friedrich Naumaun in their geo-
graphical narratives. I give the name of still active vol-
canoes to those which when seen from their immediate
vicinity, still exhibit signs of greater or less degrees of their
activity, and some which have also presented great and well-
attested eruptions in recent times. The qualification " seen
from their immediate vicinity," is of great importance, as
the present existence of activity is denied to many volcanoes,
because, when observed from the plain, the thin vapours,
which ascend from the crater at a great height, remain
invisible to the eye. Thus it was even denied, at the time of
my American travels, that Pichincha and the great volcano
of Mexico (Popocatepetl) were still active although an enter-
by Domeyko. Far to the eastward of the volcano of Antuco, in
a parallel chain of the Andes, Pop pig states that there are two
other active volcanoes,— Punhamuidda* and Unalavquen*.
Volcano of Callaqui.
Volcan de Villarica*, lat. 39° 14'.
Volcano of Chinal, lat. 39° 35'.

Volcan de Panguipulli*, lat. 4 Of0, according to Major Philippi.
(d) Betiveen the Parallels of Valdivia and the southernmost Cape of
the Island of Chiloe:
Volcano of Ranco.

Volcano of Osomo or Llanquihue; lat. 41° P'; height 7443 feet.
Volcan de Calbuco* lat. 41° 12'.
Volcano of Guanahuca (Guanegue?)
Volcano of Minchinmadom, lat. 42° 48', height 7993 feet.
Volcan del Corcovado* lat. 43° 12', height 7509 feet.
Volcano of Yanteles (Yntales), lat. 43° 29', height 8030 feet.
Upon the last four volcanoes, see Captain Fitzroy, Exped. of the

Beagle, vol. iii, p. 275, and Gilliss, vol. i, p. 13.

Volcano of San Clemente, opposite to the Peninsula de Tres Montes,
which consists, according to Darwin, of granite, lat. 46° 8'. On
the great map of South America, by La Cruz, a more southern
volcano de los Gigantes is given, opposite the Archipelago de la
Madre de Dios, in lat. 51° 4'. Its existence is very doubtful.
The latitudes in the foregoing table of volcanoes are for the most
part derived from the maps of Pissis, Allan Campbell, and Claude
Gay, in the admirable work of Gilliss (1855).

TRUE VOLCANOES. 291

prising traveller, Sebastian Wisse,76 counted 70 still burning
orifices (fumaroles) around the great active cone of eruption
in the crater of Pichincha ; and I was myself a witness,77
at the foot of the volcano in the Malpais del Llano de
Tetimpa, in which I had to measure a base-line, of an ex-
tremely distinct eruption of ashes from Popocatepetl.

In the series of volcanoes of New Granada and Quito,
which in 18 volcanoes includes 10 that are still active, and is
about twice the length of the Pyrenees, we may indicate, from
^rth to south as four smaller groups or subdivisions : —
the Paramo de Ruiz and the neighbouring volcano of Tolima
(latitude, according to Acosta, 4° 55' N.) ; Purace and Sotara,
near Popayan (lat. 2i°) ; the Volcanes de Pasto, Tuquerres
and Cumbal (lat. 2° 20' to 0° 50') ; and the series of volcanoes
from Pichincha, near Quito, to the uniritermittently active
Sangay (from the equator to 2° South latitude). This last
subdivision of the active group is not particularly remarkable
amongst the volcanoes of the New World, either by its great
length, or by the closeness of its arrangement. We now
know, also, that it does not include the highest summit, for
the Aconcagua in Chili (lat. 32° 390, of 23,003 feet, according
to Kellet, 23,909 feet, according to Fitzroy and Pentland,
besides the Nevados of Sahama (22,349 feet), Parincota
(22,030 feet), Gualateiri (21,962 feet), and Pomarape (21,699
feet), all from between 18° T and 18° 25' south latitude, are
regarded as higher than Chimborazo (21,422 feet). Never-
theless, of all the volcanoes of the new continent, the vol-
canoes of Quito enjoy the most widely spread renown, for
to these mountains of the chain of the Andes, to this high
land of Quito, attaches the memory of those assiduous astro-
nomical, geodetical, optical, and barometrical labours, directed
to important ends, which are associated with the illustrious
names of Bouguer and La Condamine. Wherever intel-
lectual tendencies prevail, wherever a rich harvest of ideas
has been excited, leading to the advancement of several
sciences at the same time, fame remains as it were locally
attached for a long time. Such fame has in like manner
belonged to Mont Blanc in the Swiss Alps, — not on account

?6 Humboldt, Kleinere Schriften, Bd. i, s. 90.

77 24th of January, 1804. See my Essai Politique sur la Nouvellt
Espagne, t. i, p. 166.

u2

292 COSMOS.

of its height, which only exceeds that of Monte Rosa by
about 557 feet, — not on account of the danger overcome
in its ascent, — but on account of the value and multiplicity
of the physical and geological views which ennoble Saus-
sure's name, and the scene of his untiring industry. Nature
appears greatest where, besides its impression on the senses,
it is also reflected in the depths of thought.

The series of volcanoes of Peru and Bolivia, still entirely
belonging to the equinoctial zone, and according to Pentland,
only covered with perpetual snow at an elevation of 16,945
feet (Darwin, Journal, 1845, p. 244), attains the maximum of
its elevation (22,349 feet) at about the middle of its length'
in the Sahama group, between 18° 7' and 18° 25' south lati-
tude. There, in the neighbourhood of Arica, appears a sin-
gular, bay-like bend of the shore, which corresponds with a
sudden alteration in the axial direction of the chain of the
Andes, and of the series of volcanoes lying to the west of it.
Thence, towards the south, the coast line, and also the vol-
canic fissure, no longer strike from south-east to north-
west, but in the direction of the meridian, a direction which
is maintained until near the western entrance into the Straits
of Magellan, for a distance of more than two thousand miles.
A glance at the map of the ramifications and groups of moun-
tains of the chain of the Andes, published by me in the year
1831, exhibits many other similar agreements between the
outline of the New Continent, and the near or distant
Cordilleras. Thus between the promontories of Aguja and
San Lorenzo (5^° to 1° south latitude), both the coast line
of the Pacific and the Cordilleras are directed from south
to north, after being directed so long from south-east to
north-west, between the parallels of Arica and Caxamarca ;
and in the same way the coast-line and the Cordilleras run
from south-west to north-east, from the mountain group of
Tmbaburu, near Quito, to that of los Robles,78 near Popayan.

'3 The mica schist mountain group de los Robles (lat. 2° 2') and of the
Paramo de las Papas (lat. 2° 20') contains the Alpine lakes, Laguna de
S. lago and L. del Buey, scarcely six miles apart ; from the former springs
the Cauca, and from the latter the Magdalena, which, being soon sepa-
rated by a central mountain chain, only unite with each other in the
parallel of 9° 27', in the plains of Mompox and Tenerife. The above-
mentioned mountain group between Popayan, Almaguer, and Timana
IM of great importance in connection with the geological question whether

TRUE VOLCANOES. 293

With regard to the geological causal connection of the agree-
ment, which is so often manifested between the outlines of

the volcanic chain of the Andes of Chili, Peru, Bolivia, Quito, and
New Granada, be connected with the mountain chain of the Isthmus
of Panama, and in this way with that of Veragua and the series of vol-
canoes of Costa Pdca and Central America in general. In my maps
of 1816, 1827, and 1831, the mountain-systems of which have been
made more generally known by Bru£ in Joaquin Acosta's fine map of
New Granada (1847) and in other maps, I have shown how the chain
of the Andes undergoes a triple division under the northern parallel
of 2° 10'; the western Cordillera running between the valley of the
Rio Cauca and the Rio Atrato; the middle one between the Cauca and
the Rio Magdalena; and the eastern one between the valley of the
Magdalena and the Llanos (plains) which are watered by the affluents
of the Maranon and Orinoco. I have been able to indicate the special
direction of these three Cordilleras from a great number of points
which fall in the series of astronomical local determinations, of which
I obtained 152 in South America alone by culminations of stars.

To the east of the Rio I^gua, and to the west of Cazeres, Rolda-
nilla, Toro, and Anserma, near Cartago, the western Cordillera runs
S.S.W.— N.N.E., as far as the Salto de San Antonio in the Rio Cauca
(lat. 5° 14') which lies to the south-west of the Vega de Supia. Thence,
as far as the Alto del Viento (Cordillera de Abibe, or Avidi, lat. 7° 12')
9600 feet in height, the chain increases considerably in elevation and
bulk, and amalgamates, in the province of Antioquia, with the inter-
mediate or Central Cordillera. Further to the north, towards the
sources of the Rios Lucio and Guacuba, the chain ceases, dividing into
ranges of hills. The Cordillera occidental, which is scarcely 32 miles
from the coast of the Pacific near the mouth of the Dagua in the
Bnhia de San Buenaventura (lat. 3° 50*) is twice this distance in the
parallel of Quibdo in the Choco (lat. 5° 48'). This observation is of
some importance, because we must not confound with the western
chain of the Andes, the country with high hills, and the range of hills,
which in this province, so rich in gold dust, runs from south to north
from Xovita and Tado along the right bank of the Rio San Juan and
the left bank of the great Rio Atrato. It is this inconsiderable series of
hills that is intersected in the Quebrada de la Raspadura, by the
canal of Raspadura (Canal des Monches), which unites two rivers (the
Rio San Juan or Noanama and the Rio Quibdo, a tributary of the
Atrato) and by their means two oceans (Humboldt, Essai Politique,^,. i,
p. 235); it was this also which was seen in the instructive expedition of
Captain Kellet between the Bahia de Cupica (lat. 6° 42*) long and fruit-
lessly extolled by me, and the sources of the Napipi, which falls
into the Atrato. (See Humboldt, Op. cit. t. i, p. 231 ; and Robert
Fitzroy, Congiderations on the Great Isthmus of Central America, in
the Journal of the Royal Gcogr. Soc. vol. xx, 1851, pp. 178, 180, and
186).

The middle chain of the Andes (Cordillera Central), constantly tha
highest, reaching within the limit of perpetual snow, and in ita entire

294 COSMOS.

continents and the direction of near mountain chains (South
America, Alleghanys, Norway, Apennines), it appears diffi-
cult to come to any decision.

extent, directed nearly from south to north, like the western chain,
commences about 35 miles to the north-east of Popayau with the
Paramos of Guanacos, Huila, Iraca, and Chinche. Further on towards
the north, between Buga and Chaparral, rise the elongated ridge of the
Nevado de Baraguan (lat. 4° II7), la Montana de Quindio, the snow-
capped, truncated cone of Tolima, the Volcano and Paramo de Ruiz
and the Mesa de Herveo. These high and rugged mountain deserts, to
which the name of Paramos is applied in Spanish, are distinguished by
their temperature and a peculiar character of vegetation, and rise in the
part of the tropical region which I here describe, according to the mean
of many of my measurements, from 10,000 to 11,700 feet above the
\evel of the sea. In the parallel of Mariquita, of the Herveo and the
Salto de San Antonio, in the valley of the Cauca, there commences a
union of the western and central chains, of which mention has already
been made. This amalgamation becomes most remarkable between
the above-mentioned Salto and the Angostura and Cascada de Cara-
manta, near Supia. Here is situated the high land of the province of
Antioquia, so difficult of access, which extends, according to Manuel
Restrepo, from 5^° to 8° 34' ; in this we may mention as points of
elevation from south to north : Arrna, Sonson, to the north of the
sources of the Rio Saiaana : Marinilla, Rio Negro (6844 feet), and
Medellin (4847 feet), the plateau of Santa Rosa (8466 feet) and Valle de
Osos. Further on, beyond Cazeres and Zaragoza, towards the conflu-
ence of the Cauca and iSechi, the true mountain chain disappears, and
the eastern slope of the Cerros de San Lucar, which I saw from Badillas
(lat. 8° I'), and Paturia (lat. 7° 36'), during my navigation and survey of
the Magdalena, is only perceptible from its contrast with the broad
river-plain.

The eastern Cordillera possesses a geological interest in as much as it
riot only separates the whole northern mountain system of New Granada
from the lowland, from which the waters flow partly by the Caguan
and Caqueta to the Amazons, and partly by the Guaviare, Meta, and
Apure to the Orinoco, but also unites itself most distinctly with the
littoral chain of Caraccas. What is called in systems of veins a raking
takes place there, — a union of mountain chains which have been ele-
vated upon two fissures of very different directions, and probably even
at very different times. The eastern Cordillera departs far more than
the two others from a meridional direction, diverging towards the
noi'th-east, so that at the snowy mountains of Merida (lat. 8° 10') ife
already lies 5 degrees of longitude further to the east, than at its issue
from the mountain group de los Robles, near the Ceja and Timana. To
the north of the Paramo de la Suma Paz, to the east of the Purificacion,
on the western declivity of the Paramo of Chingaza, at an altitude of
only 8760 feet, rises, over an oak forest, the fine but treeless and stern
plateau of Bogota (lat. 4° 36'). It occupies about 288 geog. square miles
and its position presents a remarkable similarity to that of the basin

TKUE VOLCANOES. 295

Although, in the series of volcanoes of Bolivia and Chili,
the western branch of the chain of the Ancles, which
approaches nearest to the Pacific, at present exhibits the
greater part of the traces of still existing volcanic activity,
yet, a very experienced observer, Pentland, has discovered,
at the foot of the eastern chain, more than 180 geog. miles
from the sea-coast, a perfectly preserved, but extinct crater,
with unmistakeable lava-streams. This is situated upon the
summit of a conical mountain, near San Pedro de Cacha, in

of Cashmere, which, however, according to Victor Jacquemont, is
about 3410 feet lower at the Wuller lake, and belongs to the south-
western declivity of the Himalayan chain. The plateau of Bogota and
the Paramo de Chingaza, are followed in the eastern Cordillera of the
Andes towards the north-east by the Paramos of Guachaneque, above
Tunja; of Zoraca, above Sogamoso; of Chita (16,000 feet?), near the
sources of the Eio Casanare, a tributary of the Meta; of the Almorzadera
(12,854 feet), near Socorro; of Cacota (10,986 feet), near Pamplona; of
Laura and Porquera near la Grita. Here, between Pamplona, Salazar,
and Rosario (between lat. 7° 8' and 7° 50') is situated the small moun-
tain group, from which a crest extends from south to north towards
Ocnfia and Valle de Upar, to the west of the Laguna de Maracaibo, and
unites with the most advanced mountains of the Sierra Nevado de Santa
Marta (19,000 feet?). The more elevated and vaster crest continues in
the original north-easterly direction towards Merida, Truxillo, and Bar-
quisimeto, to unite there, to the eastward of the Laguna de Maracaibo,
with the granitic littoral chain of Venezuela, to the west of Puerto Cabello.
From the Grita and the Paramo de Porquera the eastern Cordillera
rises again at once to an extraordinary height. Between the parallels
of 8° 5' and 9° 7', follow the Sierra Nevada de Merida (Mucuchies)
examined by Boussingault and determined by Codazzi trigonometri-
cally at 15,069 feet; and the four Paramos de Timotes, Niquitao, Bocon6,
and de las Rosas, full of the most beautiful Alpine plants. (See
Codazzi, Resumen de la Geografia de Venezuela, 1841, pp. 12 and 495;
and also my Asie Centrale, t. iii, pp. 258 — 262, with regard to the
elevation of the perpetual snow in this zone.) The western Cordil-
lera is entirely wanting in volcanic activity, which is peculiar to the
central Cordillera as far as the Tolima and Paramo de Ruiz, which, how-
ever, are separated from the volcano of Puracfi by nearly three degrees
of latitude. The eastern Cordillera has a smoking hill near its eastern
declivity, at the origin of the Rio Fragua, to the north-east of Mocoa
and south-east of Timana, at a greater distance from the shore of the
Pacific, than any other still active volcano of the New World. An
accurate knowledge of the local relations of the volcanoes to the
arrangement of the mountain chains is of the highest importance for
the completion of the geology of volcanoes. All the older maps,
with the single exception of that of the high land of 'Quito, can only lead
to error.

296 COSMOS.

the valley of Yucay, at an elevation of nearly 12,000 feet
(lat. 14° 8', long. 71° 20'), south-east from Cuzco, where the
eastern snowy chain of Apolobamba, Carabaya, and Vilcanoto
extends from south-east to north-west. This remarkable
point79 is marked by the ruins of a famous temple of the
Inca Viracocha. The distance from the sea of this old lava-
producing volcano is far greater than that of Sangay, which
also belongs to an eastern Cordillera, and greater than that
of Orizaba and Jorullo.

An interval of 540 miles destitute of volcanoes separates
the series of volcanoes of Peru and Bolivia from that of Chili.
This is the distance of the eruption in the desert of Atacama
from* the volcano of Coquimbo. At 2° 34' further to the
south, as already remarked, the group of volcanoes of Chili
attains its greatest elevation in the volcano of Aconcagua
(23,003 feet), which, according to our present knowledge, is
also the maximum of all the summits of the new Continent.
The average height of the Bahama group is 22,008 feet ;
consequently 586 feet higher than Chimborazo. Then follow,
diminishing rapidly in elevation, Cotopaxi, Arequipa (?), and
Tolima, between 18,877 and 18,129 feet in height. I give,
in apparently very exact numbers, and without alteration,
the results of measurements which are unfortunately com-
pounded from barometrical and trigonometrical determi-
nations, because in this way the greatest inducement will
be given to the repetition of the measurements and correc-
tion of the results. In the series of volcanoes of Chili, of
which I have cited 24, it is unfortunately for the most part
only the southern and lower ones, from Antuco to Yantales,
between the parallels of 37° 20' and 43° 40', that have been
hypsometrically determined. These have the inconsiderable
elevation of from six to eight thousand feet. Even in Tierra
del Fuego itself the summit of the Sarmiento, covered with
perpetual snow, only rises, according to Fitzroy, to 6,821
feet. From the volcano of Coquimbo to that of San
Clemente the distance is 968 miles.

79 Pentland, in Mrs. Somerville's Physical Geography (1851), vol. i,
p. 185. The Peak of Vilcanoto (17,020 feet), situated in lat. 14° 28%
forming a portion of the vast mountain group of that name, closes the
northern extremity of the plateau, in which the lake of Titicaca, a
Mna]l inland sea of 88 miles in length, is situated.

TRUE VOLCANOES 297

With regard to the activity of the volcanoes of Chili, we
have the important testimony of Charles Darwin,80 who
refers very decidedly to Osorno, Corcovado, and Aconcagua
as being ignited ; the evidence of Meyen, Poppig, and
G*y, who ascended Maipu, Antuco and Peteroa ; and that
of Domeyko, the astronomer Gilliss, and Major Philippi.
The number of active craters may be fixed at thirteen, only
five fewer than in the group of Central America.

From the five groups of serial volcanoes of the New Con
tinent, which we have been able to describe from astrono-
nomical local determinations, and for the most part also hyp-
sometrically as to position and elevation, let us now turn to
the Old Continent, in which, in complete opposition to the
New World, the greater part of the approximated volcanoes
belong not to the mainland but to the islands. Most of the
European volcanoes are situated in the Mediterranean Sea,
and indeed (if we include the great and repeatedly active
crater between Thera, Therasia, and Aspronisi), in the Tyr-
rhenian and ^Egsean parts ; in Asia the most mighty vol-
canoes are situated to the south and east of the continent
on the large and small Sunda Islands, the Moluccas, and
the Philippines, in Japan, and the Archipelagoes of the
Kurile and Aleutian Islands.

In no other region of the earth's surface do such frequent
and such fresh traces of the active communication between
the interior and exterior of our planet show themselves, as
upon the narrow space of scarcely 12,800 geographical (16.928
English) square miles between the parallels of 10° south and
14° north latitude, and between the meridians of the southern
point of Malacca and the western point of the Papuan penin-
sula of New Guinea. The area of this volcanic island- world
scarcely equals that of Switzerland, and is washed by the
seas of Sunda, Banda, Solo, and Mindoro. The single island
of Java contains a greater number of active volcanoes than
the entire southern half of America, although this island
is only 544 miles in length, that is, only one-seventh of the
length of South America. A new but long-expected light
has recently been diffused over the geognostic nature of Java
(after previous very imperfect but meritorious works by

80 See Darwin, Journal of Researches in Natural History and Geology
during the Voyage of the Beagle, 1845, pp. 275, 291, and 310.

298 COSMOS.

Horsfield, Sir Thomas Stamford Raffles and Reinwardt), by
a learned, bold, and untiringly active naturalist, Franz
Junghuhn. After a residence of more than twelve years he
has given the entire natural history of the country in an
instructive work, Java, its form, vegetable covering, and
internal structure. More than 400 elevations are carefully
determined barometrically; the volcanic cones and bell-shaped
mountains, 45 in number, are represented in profile, and all
but three81 of them were ascended by Junghuhn. More than
half (at least 28) were found to be still burning and active ;
their remarkable and various profiles are described with
extraordinary clearness, and even the attainable history of
their eruptions is investigated. No less important than the
volcanic phenomena of Java are its sedimentary formations
of the Tertiary period, which were entirely unknown to us
before the appearance of the complete work just mentioned,
although they cover three- fiftlis of the entire area of the
island, especially in the southern parts. In many districts
of Java there occur, as the remains of former widely-spread
forests, fragments, from three to seven feet in length, of sili-
cified trunks of trees, which all belong to the Dicotyledons.
For a country in which at present an abundance of palms
and tree ferns grows, this is the more remarkable, because
in the Miocene tertiary rocks of the brown-coal formation
of Europe, where arborescent Monocotyledons no longer
thrive, fossil palms are not unfrequently met with.82 By
a diligent collection of the impressions of leaves and fos-
silized woods, Junghuhn has been enabled to give us, as
the first example of the fossil Flora of a purely tropical
region, the ancient Flora of Java, ingeniously elaborated by
Goppert from his collection.

As regards the elevation to which they attain, the vol-
canoes of Java are far inferior to those of the t/lncae groups

s1 Junghuhn, Java, Bd. i, s. 79.

82 Op. cit. Bd. iii, s. 155, and Goppert, Die Tertiarflora auf der Insel
Java nach den Entdeckungen von Fr. Junghuhn (1854), s. 17. The
absence of Monocotyledons is, however, peculiar to the silicified trunks
of trees lying scattered upon the surface, and especially in the
rivulets of the district of Bantam; in the subterranean carbonaceous
strata, on the contrary, there are remains of palm-wood, belonging
to two genera (Flabellaria and Amesoneuron). See Goppert, s. 31
and 35.

TRUE VOLCANOES. 299

of Chili, Bolivia, and Peru, and even to those of the two
groups of Quito with New Granada, and of Tropical Mexico.
The maxima attained by these American groups are : — For
Chili, Bolivia, and Quito, 21,000 to 23,000 feet, and for
Mexico, 18,000 feet. This is nearly ten thousand feet
(about the height of Etna), more than the greatest elevation
of the volcanoes of Sumatra and Java. On the latter island
the highest still burning colossus is the Gunung Semeru,
the culminating point of the entire Javanese series of vol-
canoes. Junghuhn ascended this in September, 1844 ; the
average of his barometric measurements gave 12,233 feet
above the surface of the sea, and consequently 1748 feet
more than the summit of Etna, At night the centigrade
thermometer fell below 6°.2 (43°.2 Fahr.). The old Sanscrit
name of Gunung Semeru was MaM-Meru (the great Meru) ;
a reminiscence of the time when the Malays received Indian
civilisation, — a reminiscence of the Mountain of the World
in the north, which, according to the Mahabharata, is the
dwelling-place of Brahma, Vishnu, and the seven Devarschi.8*
It is remarkable that, as the natives of the plateau of Quito
had guessed, before any measurement, that Chimborazo sur-
passed all the other snowy mountains -in the country, the
Javanese also knew that the Holy Mountain Maha-Meru,
which is but at a short distance from the Gunung Ajrdjuno
(11,031 feet) exhibited the maximum of elevation upon the
island, and yet, in this case, in a country free from snow, the
greater distance of the summit from the level of the lower
limit of perpetual snow could no more serve as a guide to
the judgment than the height of an occasional temporary fall
of snow.84

The elevation of the Gunung Semeru, which exceeds
11,000 (11,726 English) feet, is most closely approached
by four other mountains, which were found hypsometrically
to be between ten and eleven thousand feet. These
are: Gunung89 Slamat, or mountain of Tegal (11,116

83 Upon the signification of the word Meru, and the conjectures
which Burnouf communicated to me regarding its connection with
mira (a Sanscrit word for sea], see my Asie Centrale, t. i, pp. 114 — 116,
and Lassen's Indische Alterthumskunde, Bd. i, s. 847. The latter is
inclined to regard the names as not of Sanscrit origin.

84 See page 240.

85 Gununrj is the Javanese word for mountain, in Malayan, gHnongl

SOO COSMOS.

feet), Gunung Ardjuno (11,031 feet), Gunung Sumbing
(11,029 feet), and Ginning Lawn (10,726 feet). Seven
other volcanoes of Java attain a height of nine or ten
thousand feet ; a result which is of the more importance as
no summit of the island was formerly supposed to rise higher
than six thousand feet.86 Of the five groups of North and
South American volcanoes, that of Guatemala (Central
America) is the only one exceeded in mean elevation by
the Javanese group. Although in the vicinity of Old
Guatemala the Volcan del Fuego attains a height of 13,109
feet (according to the calculation and reduction of
Poggendorff), and therefore 874 feet more than Gunung
Semeru, the remainder of the Central American series of
volcanoes only varies between five and seven thousand feet,
and not as in Java between seven and ten thousand feet.
The highest volcano of Asia is not, however, to be sought
in the Asiatic Islands (the Archipelago of the Sunda
Islands), but upon the continent ; for upon the peninsula
of Kamtschatka the volcano Kljutschewsk rises to 15,763
feet, or nearly to the height of the Rucu-Pichincha, in the
Cordilleras of Quito.

which singularly enough is not further disseminated over the enormous
domain of the Malayan language ; see the comparative table of words in
my brother's woi'k upon the Kawi language, vol. ii, s. 249, No. 62. As
it is the custom to place this word gunung before the names of moun-
tains in Java, it is usually indicated in the text by a simple G.

^ Leopold de Buch, Description Physique des lies Canaries, 1836,
p. 419. Not only has Java (Junghuhn, Th. i. s. 61, and Th. ii. s. 547)
a colossal mountain, the Semeru of 12,233 feet, which consequently
exceeds the Peak of Teneriflfe a little in height, but an elevation of
12,256 feet is also attributed to the Peak of Indrapura, in Sumatra,
which is also still active, but does not appear to have been so accu-
rately measured (Th. i, s. 78, and profile Map No. 1). The next to
this in Sumatra, are the dome of Telainan, which is only one of the
summits of Ophir (not 13,834, but only 9603 feet in height), and the
Merapi (according to Dr. Homer, 9571 feet) the most active of the
thirteen volcanoes of Sumatra, which, however, (Th. ii. s. 294, and
Juughuhn's Battalander, 1847, Th. i, s. 25) is not to be confounded,
from the similarity of the names, with two volcanoes of Java, — the
celebrated Merapi, near Jogjakerta (9208 feet), and the Merapi, which
forms the eastern portion of the summit of the volcano Idjen (8595
feet). In the Merapi, it '.s thought that the holy name Meru is again
to be detected, combined with the Malay an and Javanese word a$i, fira

TRUE VOLCANOES. 301

Tbe principal axis87 of the closely approximated series of
the Javanese volcanoes (more than 45 in number) has a
direction W.N.W — E.S.E. (exactly W. 12° K), and there-
fore principally parallel to the series of volcanoes of the
eastern part of Sumatra, but not to the longitudinal axis of
the island of Java. This general direction of the chain of
volcanoes by no means excludes the phenomenon to which
attention has very recently been directed in the great chain
of the Himalaya, that three or four individual high summits
are so arranged together, that the small axes of these partial
series form an oblique angle with the primary axis of the
chain. This phenomenon of fissure, which has been observed
and partially described b8 by Hodgson, Joseph Hooker, and
Strachey, is of great interest. The small axes of the subsi-
diary fissures meet the great axis, sometimes almost at a
right angle, and even in volcanic chains, the actual maxima
of elevation are often situated at some distance from the
major axis. As in most linear volcanoes, no definite pro-
portion is observed in Java, between the elevation and the
size of the crater at the summit. The two largest craters
are those of Gunung Tengger and Gunung Raon. The former
of these is a mountain of the third class, only 8704 feet in
height. Its circular crater is, however, more than 21,315 feet,
and therefore nearly four geographical miles in diameter.
The flat bottom of the crater is a sea of sand, the surface of
which lies 1865 feet below the highest point of the surrounding
wall, and in which scoriaceous lava-masses project here and
there from the layer of pounded rapilli. Even the enormous
crater of Kirauea, in Owhyhee, which is filled with glowing
lava, does not, according to the accurate trigonometrical
survey of Captain Wilkes, and the excellent observations
of Dana, attain the size of that of Gunung Tengger. In the
middle of the crater of the latter there rise four small cones
of eruption, actual circumvallated funnel-shaped chasms, of
which only one, Bromo (the mythical name Brahma, a word
which has the signification of fire, in the Kawi although

87 Junghuhn, Java, Bd. i. s. 80.

83 See Joseph Hooker, Sketch-Map of SiJchim, 1850, and in his
Himalayan Journals, vol. i, 1854, Map of part of Bengal; and also
Strachey, Map of West-Nari, in his Physical Geography of Western
Tibet, 1853.

302 COSMOS.

not in the Sanscrit), is now not active. Bromo presents the
remarkable phenomenon that from 1838 to 1842 a lake was
formed in its funnel, of which Junghuhn has proved that
it owes its origin to the influx of atmospheric waters, which
have been heated and acidulated by the simultaneous pene-
tration of sulphurous vapours.89 Next to Gunung Tengger,
Gunung Raon has the largest crater, but the diameter of
this is about one-half less. The view into the interior is
awe-inspiring. It appears to extend to a depth of more
than 2398 feet; and yet the remarkable volcano, 10,178 feet
in height, which Junghuhn has ascended and so carefully
described,90 is not even named on the meritorious map of
Raffles.

Like almost all linear volcanoes, the volcanoes of Java
exhibit the important phenomenon, that a simultaneity of
great eruptions is observed much more rarely in nearly ap-
proximated cones, than in those which are widely separated.
When, in the night of the llth and 12th of August, 1772,
the volcano Gunung Pepandajan (7034 feet) burst forth the
most destructive eruption that has taken place upon the
island within historical periods, two other volcanoes, the
Gunung Tjerimai and Gunung Slamat, became ignited on the
same night, although they lie in a straight line at a distance
of J 34 and 352 miles from Pepandajan.91 Even if the vol-
can«res of a series all stand over one focus, the net of fissures
through which they communicate is, nevertheless, certainly
BO constituted that the obstruction of old vapour-channels,

89 Junghuhn, Java, Bd. ii, fig. ix. s. 572, 596, and 601—604. From
1829 to 1848, the small crater of eruption of the Bromo had eight fiery
eruptions. The crater-lake, which had disappeared in 1842, had been
again formed in 1848, but according to the observations of B. van
Herwerden, the presence of the water in the chasm of the cauldron
had no effect in preventing the eruption of red-hot, widely-scattered
scoriae.

90 Junghuhn, Bd. ii. s. 624—641.

91 The G. Pepandajan was ascended in 1819 by Reinwardt, and in
1837 by Junghuhn. The latter, who has accurately investigated the
vicinity of the mountain, consisting of detritus intermingled with
numerous angular, erupted blocks of lava, and compared it with the
earliest reports, regards the statement, which has been disseminated
by so many valuable works, that a portion of the mountain and an
area of several square miles sank during the eruption of 1772, as
greatly exaggerated (Junghuhn, Bd. ii. s. 98 and 100).

TRUE VOLCANOES. 303

or the temporary opening of new ones, in the course of
ages, render simultaneous eruption at very distant points
quite conceivable. I may again advert to the sudden dis-
appearance of the column of smoke which ascended from
the volcano of Pasto, when, on the morning of the 4th of
February, 1797, the fearful earthquake of Riobamba con-
vulsed the plateau of Quito between Tunguragua and Coto-
paxi.*8

To the volcanoes of the island of Java generally, a cha-
racter of ribbed formation is ascribed, to which I have seen
nothing similar in the Canary Islands, in Mexico, or in the
Cordilleras of Quito. The most recent traveller, to whom
we are indebted for such admirable observations upon the
structure of the volcanoes, the geography of plants, and the
psychrometric conditions of moisture, has described the
phenomenon to which I here allude with such decided clear-
ness that I must not omit to call attention to this regularity
of- form, in order to furnish an inducement to new investi-
gations. " Although," says Junghuhii, " the surface of a vol-
cano 10,974 feet in height, the Gunung Sumbing, when seen
from some distance, appears as an uninterruptedly smooth and
sloping fkce of the conical mountain, still, on a closer examina-
tion, we find that it consists entirely of separate longitudinal
ridges or ribs, which gradually subdivide and become broader
as they advance downwards They run from the summit of
the volcano, or more frequently from an elevation several
hundred feet below the summit, down to the foot of the
mountain, diverging like the ribs of an umbrella." These
rib-like longitudinal ridges have sometimes a tortuous course
for a short distance, but are all formed by approximated
clefts of three or four hundred feet in depth, all directed in
the same way, and becoming broader as they descend. They
are furrows of the surface " which occur on the lateral slopes
of all the volcanoes of the island of Java, but differ consi-
derably from each other upon the various conical mountains,
in their average depth and the distance of their upper
origin from the margin of the crater or from an unopened
summit. The Gummg Sumbing (11,029 feet) is one of those
volcanoes which exhibit the finest and most regularly formed

92 Cosmos, vol. v, p. 183, and Voyage aux Regions Equinox, t. ii,
p. 16.

304 COSMOS.

ribs, as the mountain is bare of forest trees and clothed with
grass." According to the measurements given by Jung-
huhn,93 the number of ribs increases by division in propor-
tion as the declivity decreases. Above the zone of 9000 feet
there are, on Gunung Sumbing, only about 10 such ribs ; at
an elevation of 8,500 feet there are 32 ; at 5500 feet, 72 ; and
at 3,000 feet, more than 95. The angle of inclination at the
same time diminishes from 37° to 25° and 10|°. The ribs
are almost equally regular on the volcano Gunung Tengger
(8702 feet), whilst on the Gunung Ringgit they have been
disturbed and covered94 by the destructive eruptions which
followed the year 1586. The production of these peculiar
longitudinal ribs and the mountain fissures lying between
them, of which drawings are given, is ascribed to " erosion
by streams."

It is certain thac the mass of meteoric water in this tro-
pical region is three or four times greater than in the tem-
perate zone, indeed the showers are often like waterspouts,
for although, on the whole, the moisture diminishes with the
elevation of the strata of air, the great mountain cones exert
on the other hand a peculiar attraction upon the clouds,
and, as I have already remarked, in other places, volcanic
eruptions are in their nature productive of storms. The
clefts and valleys (Barrancos), in the volcanoes of the Canary-
Islands, and in the Cordilleras of South America, which have
become of importance to the traveller from the frequent
descriptions given by Leopold von Buch95 and myself, because
they open up to him the interior of the mountain, and some-
times even conduct him up to the vicinity of the highest
summits, and to the circumvallation of a crater of elevation,
exhibit analogous phenomena ; but although these also at
times carry off the accumulated meteoric waters, the original
formation of the barrancas96 upon the slopes of the volcanoes

93 Junghuhn, Bd. ii. s. 241 — 246.

94 Op. cit. sup. s. 566, 590 and 607—609.

95 Leopold von Buch, Phys. Besckr. der Canariscken Inseln, a. 206.
218, 248, and 289.

96 Barranco and Barranca, both of the same meaning, and suffi-
ciently in use in Spanish America, certainly indicate properly a water-
furrow or water-cleft : la quiebra que haceu en la tierra las corrientea
delas aguas ; — "uua torrente que hace barrancas;" but they also indi-

TRUE VOLCANOES. 305

is probably not to be ascribed to these. Fissures, caused
by folding in the trachytic mass, which has been elevated
whilst soft and only subsequently hardened, have probably
preceded all actions of erosion and the impulse of water.
But in those places where deep barrancos appeared in the
volcanic districts visited by me on the declivities of bell
shaped or conical mountains (en lasfaldas de los Cerros bar-
rancosos), no trace was to be detected of the regularity, or
radiate ramification with which we are made acquainted by
Junghuhn's works in the singular outlines of the volcanoes
of Java.97 The greatest analogy with the form here re-
ferred to is presented by the phenomenon to which Leopold
von Buch, and the acute observer of volcanoes, Poulet
Scrope, have already directed attention, namely, that great
fissures almost always open at a right or obtuse angle from
the centre of the mountain, radiating (although undivided),
in accordance with the normal direction of the declivities,
but not transversely to them.

The belief in the complete absence of lava-streams upon
the island of Java,98 to which Leopold von Buch appeared to

cate any chasm. But that the word barranca is connected with barro,
clay, soft, moist loam, and also road-scrapings, is doubtful.

97 Lyell, Manual of Elementary Geology, 1855, chap, xxix, p. 497.
The most remarkable analogy with the phenomenon of regular rib-
bing in Java, is presented by the surface of the Mantle of the Somma
of Vesuvius, upon the seventy folds of which, an acute and accurate
observer, the astronomer Julius Schmidt, has thrown mv Jo. light (Die
Eruption des Vesuvs im Mai, 1855, s. 101 — 109). According to
Leopold von Buch, these valley-furrows are not originally rain-fur-
rows (fiumare), but consequences of cracking (folding, etoilement) dur-
ing the first upheaval of the volcano. The usually radial position
of the lateral eruptions in relation to the axis of the volcano, also
appears to be connected therewith (s. 129).

93 " Obsidian, and consequently pumice-stones, are as rare in Java
as trachyte itself. Another very curious fact is the absence of any
stream of lava in that volcanic island. M. Reinwardt, who has him-
self observed a great number of eruptions, says expressly that
there havn never been instances of the most violent and destructive
eruption having been accompanied by lavas." — Leopold de Buch,
Descr. des lies Canaries, p. 419. Amongst the volcanic rocks of Java,
for which the Cabinet of Minerals at Berlin is indebted to Dr. Juug-
huhn, dioritic-trachytes are most distinctly recognizable at Burung-
agung, s. 255 of the Leidner catalogue, at Tjinas, s. 232, and in the
Gunung Parang, situated in the district Batu-gaugi. This is couse-
VOL. V. X

306 COSMOS.

incline in consequence of the observations of Beinwardt, has
been rendered more than doubtful by recent observations.
Junghuhn, indeed, remarks " that the vast volcano Gunung
Merapi has not poured forth coherent, compact lava-streams
within the historical period of its eruptions, but has only
thrown out fragments of lava (rubbish), or incoherent blocks
of stone, although for nine months, in the year 1837, fiery
streams were seen at night running down the cone of
eruption."99 But the same observant traveller has distinctly

quently the identical formation of dioritic-trachyte of the volcanoes
of Orizaba and Toluca in Mexico, of the island Panaria in the Lipari
Islands, and of JEgina in the JSgean Sea !

99 Junghuhn, Bd. ii. s. 309 and 314. The fiery streaks which were
seen on the volcano G. Merapi, were formed by closely approximated
streams of scoriae (trainees de fragmens), by non-coherent masses,
which roll down during the eruption towards the same side, and strike
against each other from their very different weights on the steep
declivity. In the eruption of the G. Lamongau on the 26th March,
1847, a moving line of scoriae of this kind divided into two branches
several hundred feet below its point of origin. " The fiery streak,"
we find it expressly stated (Bd. ii. s. 767), " did not consist of true
fused lava, but of fragments of lava rolling closely after one another."
The G. Lamongan and the G. Semeru are the two volcanoes of the
island of Java, which are found to be most similar, by their activity
in long periods, to the Stromboli, which is only about 2980 feet
high, as they, although so remarkably different in height (the Lamon-
gan being 5340 and the Semeru 12,235 feet high), exhibited eruptions
of scoriae, the former after pauses of 15 to 20 minutes (eruptions of
July, 1838, and March, 1847), and the second of 1£ to 3 hours
(eruptions of August, 1836, and September, 1844,) (Bd. ii. s. 554 and
765 — 769). At Stromboli itself, together with numerous eruptions of
scoriae, small, but rare effusions of lava also occur, which, when
detained by obstacles, sometimes harden on the declivities of the
cone. I lay great stress upon the various forms of continuity or
division, under which completely or partially fused matters are thrown
or poured out, whether from the same or different volcanoes. Ana-
logous investigations, undertaken under various zones, and in accord-
ance with guiding ideas, are greatly to be desired, from the poverty
and great one-sidedness of the views, to which the four active Euro-
pean volcanoes lead. The question raised by me in 1802 and by my
friend Boussingault in 1831, — whether the Antisana in the Cordilleras
of Quito has furnished lava-streams? which we shall touch upon
hereafter, may perhaps find its solution in the division of the fluid
matter. The essential character of a lava-stream is that of a uniform,
coherent fluid, — a band-like stream, from the surface of which scales
separate during its cooling and hardening. These scales, beneath
which the nearly homogeneous lava long continues to flow, upraise

TRUE VOLCANOES. 307

described, in great detail, three black, basaltic lava-streams
on three volcanoes : — Gunung Tengger, Gunung Idjen, and
Slamat.100 On the latter the lava-stream, after giving rise to
a water-fall, is continued into the tertiary rocks.1 From such
true effusions of lava, which, form coherent masses, Junghuhn
very accurately distinguishes, in the eruption of Gunung
Lamongan,2 on the 6th July, 1838, what he calls a stone-
stream, consisting of glowing and usually angular fragments,
erupted in a row. " The crash was heard of the breaking
stones, which rolled down, like fiery points, either in a line
or without any order." 1 purposely direct especial attention
to the very various modes in which fiery masses appear on
the slopes of a volcano, because in the dispute upon the
maximum angle of fall of lava-streams, glowing streams of
stones (masses of scoriae) following each other in rows, are
sometimes confounded with continuous lava-streams.

As the important problem of the rarity or complete defici-
ency of lava-streams in Java, — a problem which touches on the

themselves in part, obliquely or perpendicularly, by the inequality of
the internal movement and the evolution of hot gases ; and when,
in this way, several lava-streams, flowing together, form a lava lake,
as in Iceland, a field of detritus or fragments is produced on their
cooling. The Spaniards, especially in Mexico, call such a district,
which is very disagreeable to pass over, a malpais. Such lava-fields,
which are often found in the plain at the foot of a volcano, remind
one of the frozen surface of a lake, with short, upraised ice-blocks.

100 The name G. Idjen, according to Buschmann, may be explained
by the Javanese word hidjdn, singly, alone, separately : — a derivative
from the substantive hidji or widji, grain, seed, which with sa ex-
presses the number one. With regard to the etymology of G.
Tengger, see the important work of my brother upon the connections
between Java and India (Kawi-Sprache, Bd. i, s. 188\ where there
is a reference to the historical importance of the Tengger Mountain,
which is inhabited by a small tribe of people, who, opposed to the
now general Mahomedanism of the island, have retained their ancient
Indo-Javanic faith. Junghuhn, who has very industriously explained
the names of mountains from the Kawi language says (Th. ii. s. 554),
that in the Kawi, Tengger signifies hill ; the word also receives the
same signification in Gericke's Javanese Dictionary (Javaansch-neder-
duitsch Woordenboek. Amst., 1847). Slamat, the name of the high
volcano of Tegal, is the well-known Arabic word selamat, which sig-
nifies happiness and safety.

1 Junghuhn, Bd. ii. Slamat, 8. 153 and 163 ; Idjen, ». C98; Tengger,
a. 773.

2 Bd. ii. s. 760—762.

x 2

308 COSMOS.

internal constitution of volcanoes, and, which I must add, has
not been treated with sufficient earnestness, has recently been
so often spoken of. the present appears a fitting place in which
to bring it under a more general point of view. Although
it is1 very probable that, in a group or series of volcanoes all
the members stand in a certain common relation to the
general focus, the molten interior of the earth, still each
individual presents peculiar physical and chemical processes
as regards strength and frequency of activity, degree and
form of fluidity, and material difference of products, — pecu-
liarities which cannot be explained by the comparison of the
form, and elevation above the present surface of the sea.
The gigantic mountain, Sangay, is as uninterruptedly
active as the lowly Stromboli ; of two neighbouring vol-
canoes, one throws out pumice-stone without obsidian, the
other both at once ; one furnishes only loose cinders, the
other lava flowing in narrow streams. These characteristic
processes, moreover, in many volcanoes appear not to have
been always the same at various epochs of their activity.
To neither of the two continents is rarity or total absence of
lava streams to be peculiarly ascribed. Remarkable distinc-
tions only occur in those groups with regard to which we
must confine ourselves to definite historical periods near to
our own times. The non-detection of single lava-streams
depends simultaneously upon many conditions. Amongst
these we may instance the deposition of vast layers of tufa,
rapilli, and pumice-stone ; the simultaneous and non-simul-
taneous confluence of several streams, forming a widely ex-
tended lava-field covered with detritus ; the circumstance that
in a wide plain the small conical eruptive-cones, the volcanic

Elatform, as it were, from which, as at Lancerote, the lava
ad flowed forth in streams, have long since been destroyed.
In the most ancient conditions of our unequally cooling planet,
in the earliest foldings of its surface, it appears to me very pro-
bable that a frequent viscid outflow of trachytic and doleritic
rocks, of masses of pumice-stone or perlite, containing obsi-
dian took place from a composite network of fissures, over
which no platform has ever been elevated or built up. The
problem of such simple effusions from fissures deserves the
attention of geologists.

In the series of Mexican volcanoes, the greatest and, since

TRUE VOLCANOES. 309

my American travels, the most celebrated phenomenon is
the elevation of the newly produced Jorullo, and its effusion
of lava. This volcano, the topography of which, founded
on measurements, I was the first to make known3, by its
position between the two volcanoes of Toluca and Colima,
and by its eruption on the great fissure of volcanic activity*,
which extends from the Atlantic Ocean to the Pacific, pre-
sents an important geognostic phenomenon, which has con-
sequently been all the more the subject of dispute. Fol-
lowing the vast lava-stream which the new volcano poured
out, I succeeded in getting far into the interior of the
crater, and in establishing instruments there. The eruption
in a broad and long-peaceful plain in the former province of
Michuacan, in the ni<jht from the 28th to the 29th of Sep-
tember, 1759, at a distance of more than 120 miles from
any other volcano, was preceded for fully two (?) months,
namely, from the 29th June in the same year, by an unin-
terrupted subterranean noise. This differed from the won-
derful bramidos of Guanaxuato, which I have elsewhere
described5 by the circumstance that it was, as is usually
the case, accompanied by earthquakes, which were not
felt in the mountain city in January, 1784. The erup-
tion of the new volcano, about 3 o'clock in the morning,
was foretold the day before by a phenomenon which, in
other eruptions, does not indicate their commencement but
their conclusion. At the point where the great volcano now
stands, there was formerly a thick wood of the Guayava
(Psidium pyriferum), so much valued by the natives on ac-
count of its excellent fruit. Labourers from the sugar-cane
fields (cafiaverales) of the Hacienda de San Pedro Jorullo,
belonging to the rich Don Andres Pimentel, who was then
living in Mexico, had gone out to collect the fruit of the
guayava. When they returned to the farm (hacienda) it
was remarked with astonishment that their large straw hats
were covered with volcanic ashes. .Fissures had, conse-
quently, already opened in what is now called the Malpais,
probably at the foot of the high basaltic dome el Cuiche.

3 Atlas Gfeographique et Physique, accompanying the Relation His-
torique, 1814, pi. 28 and 29.

4 Cosmos, vol. v. pp. 279 — 280.

* Cosmos, vol. i. p. 205, and vol. v. p. 179.

310 COSMOS.

which threw out these ashes (rapilli) before any change
appears to have occurred in the plain. From a letter of
Father Joaquin de Ansogorri, discovered in the Episcopal
archives of Valladolid, which was written three weeks after
the day of the first eruption, it appears evident that Father
Isidro Molina, sent from the neighbouring Jesuits' College
of Patzcuaro " to give spiritual comfort to the inhabitants
of the Playas de Jorullo, who were extremely disquieted by
the subterranean noise and earthquakes," was the first to
perceive the increasing danger, and thus caused the preser-
vation of the small population.

In the first hours of the night the black ashes already lay
a foot deep ; every one fled towards the hill of Aguasarco,
a small Indian village, situated 2409 feet higher than the
old plain of Jorullo. From this height (so runs the tra-
dition) a large tract of land was seen in a state of fearful
fiery eruption, and " in the midst of the flames (as those
who witnessed the ascent of the mountain expressed them-
selves) there appeared, like a black castle (castillo negro), a
great, shapeless mass (bulto grande)". From the small po-
pulation of the district (the cultivation of indigo and cotton
was then but very little carried on) even the force of long-
continued earthquakes cost no human lives, although, as
I learn from manuscript records6, houses were over-

6 In my JEssai Politique sur la Nouvelle-Espagne, in the two editions
of 1811 and 1827 (in the latter, t. ii, pp. 165 — 175), I have, as the nature
of that work required, only given a condensed abstract from my
journal, without being able to furnish a topographical plan of the
vicinity or a chart of the altitudes. From the importance which
has been assigned to this great phenomenon of the middle of the last
century, I have thought it necessary to complete this abstract here.
I am indebted for particular details relating to the new volcano of
Jorullo to an official document, written three weeks after the day of
the first eruption, but only discovered in the year 1830 by a very
scientific Mexican clergyman, Don Juan Jose* Pastor Morales; and
also to oral communications from my companion, the Biscayan Don
Ramon Espelde, who had been able to examine living eye-witnesses
of the first eruption. Morales discovered in the Archives of the
Bishop of Michuacan, a report addressed on the 19th of October, 1759,
by Joaquin de Ansogorri, Priest in the Indian village la Guacana, to
his Bishop. In his instructive work (Aufenthalt undReisen in Mexico,
1836) Burkart has also given a short extract from it (Bd. i. s. 230).
At the time of my journey, Don Ramon Espelde was living on the

TRUE VOLCANOES. 311

turned by them near the copper mines of Inguaran, in the
small town of Patzcuaro, in Santiago de Ario, and many

plain of Jorullo, and has the merit of having first ascended the
summit of the volcano. Some years afterwards he attached himself
to the expedition made on the 10th March, 1789, by the Intendente
Corregidor, Don Juan Antonio de Riano. To the same expedition
belonged a well-informed German, Franz Fischer, who had entered the
Spanish service as a Mining Commissary. By means of the latter the
name of the Jorullo first became known in Germany, as he mentioned
\i in a letter in the Schriften der Gesellschaft der JBergbaukunde, Bd. ii.,
s. 441. But the eruption of the new volcano had already been re-
ferred to in Italy, — in Clavigero's Storia antica del Messico (Cesena,
1780, t. i, p. 42), and hi the poetical work, Rusticatio Mexicana of
Father Raphael Landivar (ed. altera, Bologna, 1782, p. 17). In his
valuable work, Clavigero erroneously places the production of the
volcano, which he writes Juruyo, in the year 1760, and enlarges the
description of the eruption by accounts of the shower of ashes, ex-
tending as far as Queretaro, which had been communicated to him
in 1766 by Don Juan Manuel de Bustamente, Governor of the Pro-
vince of Valladolid de Michuacan, as an eye-witness of the pheno-
menon. The poet Landivar, an enthusiastic adherent, like Ovid, of
our theory of upheaval, makes the Colossus rise, in euphonious hexa-
meters, to the full height of 3 milliaria, and finds the thermal springs
(after the fashion of the ancients) cold by day and warm at night.
But I saw the thermometer rise to 126^° in the water of the Rio
de Cuitimba about noon.

In 1789, and consequently in the same year that the report of the
Governor Riano and the Mining Commissary Franz Fischer, appeared in
the Gazeta de Mexico, in the fifth part of his large and useful Diccionario
geogrdfico-historico de las Indias Occidentals 6 America, in the article
Xurullo, pp. 374 — 375) Antonio de Alcedo gave the interesting infor-
mation that, when the earthquakes commenced (29th June, 1759) in
the Playas, the western volcano of Colima, which was in eruption,
suddenly became quiet, although it is at a distance of " 70 leguas" (as
Alcedo says: according to my map only 112 geog. miles !) from the
Playas. " It is thought," he adds, " that the materials in the
bowels of the earth have met with obstacles to their following their
old course ; and as they have found suitable cavities (to the east,"
they have broken out at Jorullo — para reventar en Xurullo). —
Accurate topographical statements regarding the neighbourhood of
the volcano occur also in Juan Jose" Martinez de Lejarza's geogra-
phical sketch of the ancient Taraskian country : A ndlisis estadistico
de la provincia de Michuacan en 1822 (Mexico, 1824), pp. 125, 129,
130, and 131. The testimony of the author, living at Valladolid in
the vicinity of Jorullo, that, since my residence in Mexico, no trace
of an increased activity has shown itself in the mountain was the
earliest contradiction of the report of a new eruption in the year
1819 (Lyell, Principles of Geology, 1855. p. 430). As the position of

512 COSMOS.

miles further, but not beyond San Pedro Churumucu. In
the Hacienda de Jorullo, during the general nocturnal
flight, they forgot to remove a deaf and dumb negro slave.
A mulatto had the humanity to return and save him,
while the house was still standing. It is still narrated
that he was found kneeling, with a consecrated taper in
Jorullo in latitude is not without importance, I have noticed that
Lejarza, who otherwise always follows my astronomical determi-
nations of position, and who gives the longitude of Jorullo exactly
like myse.f as 2° 25' west of the meridian of Mexico (101° 29' west
of Greenwich), differs from me in the latitude. Is the latitude attri-
buted by him to the Jorullo (18° 53' 30''), which comes nearest to
that of the volcano of Popocatepetl (18° 59' 47"), founded upon re-
cent observations unknown to me? In my Recueil d'Observ. Astrono-.
miques, vol. ii, p. 521, I have said expressly, " Latitude supposee, 19° 8',
deduced from good astronomical observations at Valladolid, which
gave 19° 52' 8", and from the Itinerary direction." I only recognized
the importance of the latitude of Jorullo, when subsequently I was
drawing up the great map of Mexico in the capital city and inserting
the E. — W. series of volcanoes.

As in these considerations upon the origin of Jorullo, I have repeat-
edly mentioned the traditions which still prevail in the neighbourhood,
I will conclude this long note by referring to a very popular tradition,
which I have already touched upon in another work (Essai Politique
sur la Nouvelle Espagne, t. ii, 1827, p. 172):—" According to the belief
of the natives, these extraordinary changes which we have just
described, are the work of the monks, the greatest, perhaps, that they
have produced in either hemisphere. At the Playas de Jorullo, in
the hut that we occupied, our Indian host told us that, in 1759, the
Capuchins belonging to the mission preached at the station or San
Pedro, but that, not having been favourably received, they charged
this beautiful and fertile plain, with the most horrible and compli-
cated imprecations, prophesying that first of all the house would be
devoured by flames which would issue from the earth, and that after-
wards the surrounding air would become cooled to such a degree that
the neighbouring mountains wou^d remain eternally covered with
snow and ice. The former of these Maledictions having had such fatal
consequences, the lower class of Indians already see in the gradual
cooling of the volcano, the presage of a perpetual winter."

Next to that of the poet, Father Landivar, the first printed account of
the catastrophe was probably that already mentioned in the Gazeta de
Mexico of the 5th May, 1789 (t. iii, Num. 30, pp. 293—297) ; it bears
the modest title, Superficial y nada facultativa Description del estado
en que se hallaba el Volcdn de Jorullo la manana del dia 10 de Marzo de
1789, and was occasioned by the expedition of Riano, Franz Fischer,
and Espelde. Subsequently (1791) in the naval astronomical expedi-
tion of Malaspina, the botanists, Mocino and Don Martin Sesse, visited
Jorullo, from the Pacific coast.

TRUE VOLCANOES. 313

his hand, before the picture of Nuestra Senora de Gua-
dalupe.

According to the tradition, widely and concordantly
spread amongst the natives, the eruption, during the first
days, consisted of great masses of rock, scoriae, sand, and
ashes, but always combined with an effusion of muddy water.
In the memorable report, already mentioned, of the 19th
of October, 1759, the author of which was a man who,
possessing an accurate knowledge of the locality, describes
what had only just taken place, it is expressly said : Que
espele el dicho Volcan arena, ceniza y agua. All eye-witnesses
relate (I translate from the description which the Inten-
dant, Colonel Riano, and the German Mining Commissary,
Franz Fischer, who had passed into the Spanish service,
have given of the condition of the volcano of Jorullo on
the 10th March, 1789), " that before the terrible mountain
made its appearance (antes de reventar y aparecerse este
terrible Cerro), the earthquakes and subterranean noises
became more frequent ; but on the day of the eruption
itself the flat soil was seen to rise perpendicularly (se ob-
servo, que el plan de la tierra se levantaba perpendicular-
mente), and the whole became more or less inflated, so that
blisters (vexigones) appeared, of which the largest is now
the volcano (de los que el mayor es hoy el Cerro del Vol-
can). These inflated blisters, of very various sizes, and
partly of a tolerably regular, conical form, subsequently
burst (estas ampollas, gruesas vegigas 6 conos diferente-
mente regulares en sus figuras y tamanos,reventaron despues),
and threw boiling hot earthy mud from their orifices (tierras
hervidas y calientes), as well as scoriaceous stony masses (pie-
dras cocidas ? y fundidas), which are still found, at an
immense distance, covered with black stony masses."

These historical records, which we might, indeed, wish to
see more complete, agree perfectly with what I learnt from
the mouths of the natives 14 years after the ascent of An-
tonio de Riano. To the questions, whether "the castle
mountain," was seen to rise gradually for months or years,
or whether it appeared from the very first as an elevated
peak, no answer could be obtained. Riano's assertion that
further eruptions had taken place in the first 16 or 17
years, and therefore up to 1776, was declared to be untrue.

314 COSMOS.

According to the tradition, the phenomena of small erup-
tions of water and mud which were observed during the
first days simultaneously with the incandescent scorias, are
ascribed to the destruction of two brooks, which, springing
on the western declivity of the mountain of Santa Ines, and
consequently to the east of the Cerro de Cuiche, abundantly
irrigated the cane-fields of the former Hacienda de San
Pedro de Jorullo, and flowed onwards far to the west to the
Hacienda de la Presentacion. Near their origin, the point
is still shown where they disappeared in a fissure with their
formerly cold waters, during the elevation of the eastern
border of the Malpais. Running below the Hornitos, they
reappear, according to the general opinion of the people of
the country, heated, in two thermal springs. As the ele-
\ ated part of the Malpais is there almost perpendicular, they
form two small waterfalls, which I have seen and represented
in my drawing. For each of them the previous name, Rio
de San Pedro and Rio de Cuitimba, has been retained. At
this point I found the temperature of the steaming water to
be 126°'8. During their long course the waters are only
heated, but not acidulated. The test papers, which I usually
carried about with me, underwent no change ; but further
on, near the Hacienda de la Presentacion, towards the
Sierra de las Canoas, there flows a spring impregnated with
sulphuretted hydrogen gas, which forms a basin of 20 feet
in breadth.

In order to acquire a clear notion of the complicated outline
and general form of the surface of the ground, in which such
remarkable upheavals have taken ^lace, we must distinguish
hypsometrically and morphologically : — 1. The position of
the volcanic system of Jorullo in relation to the average level
of the Mexican plateau ; 2. The convexity of the Malpais,
which is covered by thousands of hornitos ; 3. The fissure
upon which six large, volcanic, mountain-masses have arisen.

On the western portion of the Central Cordillera of Mexico,
which strikes from S.S.E. to N.N.W., the plain of the
Playas de Jorullo, at an elevation of only 2557 feet above
the level of the Pacific, forms one of the horizontal moun-
tain terraces, which, everywhere in the Cordilleras, interrupt
the line of inclination of the declivity, and consequently
more or less impede the decrease of heat in tho superposed

TRUE VOLCANOES. 315

strata of the atmosphere. On descending from the central
plateau of Mexico (whose mean elevation is 7460 feet),
to the corn-fields of Yalladolid de Michuacan, to the charm-
ing lake of Patzcuaro, with the inhabited islet Janicho
and into the meadows around Santiago de Ario, which
Bonpland and I found adorned with the dahlias which have
since become so well known, we have not descended more
than nine hundred or a thousand feet. But in parsing from
Ario on the steep declivity over Aguasarco into the level of
the old plain of Jorullo, we diminish the absolute elevation in
this short distance by from a^O to 4250 feet7. The roundish,
convex part of the upheaved plain is about 12,790 feet in
diameter, so that its area is more than seven square miles.
The true volcano of" Jorullo and the five other mountains
which rose simultaneously with it upon the same fissure, are
so situated that only a small portion of the Malpais lies to
the east of them. Towards the west, therefore, the number
of hornitos is much larger, and when in early morning I
issued from the Indian huts of the Play as de Jorullo, or
ascended a portion of the Cerro del Mirador, I saw the black
volcano projecting very picturesquely above the innumerable
white columns of smoke of the "little ovens" (hornitos).
Both the houses of the Playas and the basaltic hill Mira-
dor are situated upon the level of the old non- volcanic, or,
to speak more cautiously, un-upheaved soil. Its beautiful
vegetation, in which a multitude of salvias bloom beneath
the shade of a new species of fan palm (CorypTia pumos),
and of a new alder (Alnus Jorullensis), contrasts with the
desert, naked aspect of the Malpais. The comparison of the
height of the barometer8 at the point where the upheaval

" My barometric measurements give for Mexico 1168 toises (7470
feet), Valladolid 1002 toises (6409 feet), Patzcuaro 1130 toises (7227
feet), Ario 994 toises (6358 feet), Aguasarco 780 toises (4^89 feet), for
the old plain of the Playas de Jorullo 404 toises (2584 fett) (Humboldt,
Observ. Astron, vol. i, p. 327, Nivellement Barometrique, No. 366 — 370).

8 If the old plain of the Playas be 404 toises (2584 feet), I find for
the maximum of convexity of the Malpais above the sea-level 487
toises (3115 feet) ; for the ridge of the great lava-strearn 600 toises
(3838 feet); for the highest margin of the crater 667 toises (4266 feet):
for the lowest point of the crater at which we could establish the
barometer 644 toises (4119 feet). Consequently the elevation of the
summit of Jorullo above the old plain appeared to be 263 toises or
1682 feet.

316 COSMOS.

commences in the Playas, with that at the point immediately
at the foot of the volcano, gives 473 feet of relative per-
pendicular elevation. The house that we inhabited stood
only about 500 toises (3197 feet) from the border of the
Malpais. At that place there was a small perpendicular pre-
cipice of scarcely 12 feet high, from which the heated water
of the brook (Rio de San Pedro) falls down. The portion
of the inner structure of the soil which I could examine at
the precipice, showed black, horizontal, loamy strata, mixed
with sand (rapilli). At other points which I did not see,
Burkart has observed "on the perpendicular boundary of
the upheaved soil, where the ascent of this is difficult, a light
gray and not very dense (weathered) basalt, with numerous
grains of olivine."9 This accurate and experienced observer
has, however,10 like myself, on the spot, conceived the idea of
a vesicular upheaval of the surface effected by elastic va-
pours, in opposition to the opinion of celebrated geogno-
sists11, who ascribe the convexity, which I ascertained by
direct measurement, solely to the greater effusion of lava
at the foot of the volcano.

The many thousand small eruptive cones (properly rather
of a roundish or somewhat elongated, oven-like form) which
cover the upheaved surface pretty uniformly, are on the
average 4 to 9 feet in height. They have risen almost ex-

9 Burkart, Aufenthalt und Reisen in Mexico in den JaJiren, 1825 —
1834, Bd. i (1836), p. 227.

10 Op. tit. sup. Bd. i, pp. 227 and 230.

11 Poulett Scrope, Considerations on Volcanoes, p. 267; Sir Charles
Lyell, Principles of Geology, 1853, p. 429; Manual of Geolugy, 1855,
p. 580 ; Daubeny on Volcanoes, p. 337. See also " on the elevation
hypothesis," Dana, Geology, in the United States Exploring Expedition,
vol. x, p. 369. Constant Prevost, in the Comptes rendus, t. xli (1855),
pp. 866 — 876, and 918 — 923 : sur les eruptions et le drapeau de I'infail-
libilite." See also, with regard to Jorullo, Carl Pieschel's instructive
description of the volcanoes of Mexico, with illustrations by Dr. Gum-
precht, in the Zeitschrift fur Allg. Erdkunde of the Geographical Society
of Berlin (Bd. vi, s. 490 — 517); and the newly published picturesque
views in Pieschel's Atlas der Vulkane der Republilc Mexico, 1856,
tab. 13, 14, and 15. The Royal Museum of Berlin, in the department
of engravings and drawings, possesses a splendid and numerous col-
lection of representations of the Mexican volcanoes (more than 40
sheets), taken from nature by Moritz Kugendas. Of the most western
of all Mexican volcanoes, that of Colima alone, this great master has
furnished fifteen coloured views.

TRUE VOLCANOES. 317

clusively on the western side of the great volcano, as indeed,
the eastern part towards the Cerro de Cuiche, scarcely con-
stitutes aV^ °f the entire area of the vesicular elevation of
the Playas. Each of the numerous hornitos is composed of
weathered basaltic spheres, with fragments separated like
concentric shells ; I was frequently able to count from 24 to
28 such shells. The balls are flattened into a somewhat
spheroidal form, and are usually 15 — 18 inches in diameter,
but vary from 1 to 3 feet. The black basaltic mass is pene-
trated by hot vapours and broken up into an earthy form,
although the nucleus is of greater density, whilst the shells,
when detached, exhibit yellow spots of oxide of iron. Even
the soft, loamy mass which unites the balls is, singularly
enough, divided into curved lamellae, which wind through
all the interstices of the balls. At the first glance I asked
myself whether the whole, instead of weathered basaltic
spheroids, containing but little olivine, did not perhaps pre-
sent masses disturbed in the course of their formation. But
in opposition to this we have the analogy of the hills of glo-
bular basalt, mixed with layers of clay and marl, which are
found, often of very small dimensions, in the central chain of
Bohemia, sometimes isolated and sometimes crowning long
basaltic ridges at both extremities. Some of the hornitos
are so much broken up, or have such large internal cavities,
that mules when compelled to place their fore-feet upon the
flatter ones, sink in deeply, whilst in similar experiments
which I made, the hills constructed by the termites, re-
sisted.

In the basaltic mass of the hornitos I found no immersed
scoria?, or fragments of old rocks which had been penetrated,
AS is the case in the lavas of the great Jorullo. The appel-
lation Hornos or Hornitos is especially justified by the cir-
cumstance that in each of them (I speak of the period when
I travelled over the Playas de Jorullo and wrote my journal,
18 September, 1803,) the columns of smoke break out, not
from the summit, but laterally. In the year 1780, cigars
might still be lighted when they were fastened to a stick
and pushed in to a depth of 2 or 3 inches ; in some places
the air was at that time so much heated by the vicinity of
the hornitos, that it was necessary to turn away from
one's proposed course. Notwithstanding the refrigeration

318 COSMOS.

which, according to the universal testimony of the Indians,
the district had undergone within 20 years, I found the
temperature in the fissures of the hornitos to range between
199° and 203° ; and at a distance of twenty feet from some
hills, the temperature of the air was still 108°'5 and 1160>2,
at a point where no vapours reached me ; the true tem-
perature of the atmosphere of the Playas being at the same
time scarcely 77°. The weak sulphuric vapours decolo-
rized strips of test paper, and rose visibly, for some hours
after sunrise, to a height of fully 60 feet. The view of
the columns of smoke was most remarkable early in a cool
morning. Towards midday, and even after 11 o'clock, they
had become very low and were visible only from their imme-
diate vicinity. In the interior of many of the hornitos we
heard a rushing sound like the fall of water. The small ba-
saltic hornitos are, as already remarked, easily destructible.
When Burkart visited the Malpais, 24 years after me, he
found that none of the hornitos were still smoking ; their
temperature being in most cases the same as that of the
surrounding air, while many of them had lost all regularity
of form by heavy rains and meteoric influences. Near the
principal volcano Burkart found small cones, which were
composed of a brownish-red conglomerate of rounded or
angular fragments of lava, and only loosely coherent. In
the midst of the upheaved area, covered with hornitos, there
is still to be seen a remnant of the old elevation on which
the buildings of the farm of San Pedro rested. The hill,
which I have indicated in my plan, forms a ridge directed
east and west, and its preservation at the foot of the great
volcano is most astonishing. Only a part of it is covered
with dense sand (burnt rapilli). The projecting basaltic
rock, grown over with ancient trunks of Ficus indica and
Psidium, is, certainly, like that of the Cerro del Mirador
and the high mountain masses which bound the plain to
the eastward, to be regarded as having existed before the
catastrophe.

It remains for me to describe the vast fissure upon which
a series of six volcanoes has risen, in the general direction
from south-south-west to north-north-east. The partial
direction of the first three, less elevated volcanoes situated
most southerly is S.W — N.E. ; that of the three following

TRUE VOLCANOES. 319

near S. — N. The fissure lias consequently been curved,
and has changed its strike throughout its total length
of 10,871 feet. The direction here indicated of the linear
but not contiguous mountains is certainly nearly at right
angles with the line upon which, according to my observation,
the Mexican volcanoes follow each other from sea to sea.
But this difference is the less surprising if we consider that
a great geognostic phenomenon (the relation of the principal
masses to each other across a continent) is not to be con-
founded with the local conditions and direction of a single
group. The long ridge of the great volcano of Pichincha
also, is not in the same direction as the series of volcanoes
of Quito ; and in non- volcanic chains, for example in the
Himalaya, the culminating points are often situated, as
I have already pointed out, at a distance from the general
line of elevation of the chain. They are situated upon par-
tial snowy ridges which even form nearly a right angle with
this general line of upheaval.

Of the six volcanic hills which have risen upon the above-
mentioned fissure, the first three, the more southern ones,
between which the road to the copper mines of Inguaran
passes, appear, in their present condition, to be of least im-
portance. They are no longer open, and are entirely covered
with grayish white, volcanic sand, which however does not
consist of pumice-stone, for I have seen nothing either of
pumice or obsidian in this region. At Jorullo also, as at
Vesuvius according to the assertion of Leopold von Buch and
Monticelli, the last covering-fall of ashes appears to have been
the white one. The fourth, more northern mountain is the
large, true volcano of Jorullo, the summit of which, not-
withstanding its small elevation (4265 feet above the sea
level, 1151 feet above the Malpais at the foot of the volcano,
and 1681 feet above the old soil of the Playas), I had
some difficulty in reaching, when I ascended it with Bon-
pland and Carlos Montufar on the 19th September, 1803.
We thought we should be most certain of getting into the
crater, which was still filled with hot sulphurous vapours,
by ascending the steep ridge of the vast lava-stream, which
burst forth from the very summit. The course passed over a
crisp, scoriaceous, clear-sounding lava, swelled up in a coke-
like, or rather cauliflower-like form. Some parts of it have

320 COSMOS.

a metallic lustre : other,? are basaltic and full of small gra-
nules of olivine. When we had thus ascended to the upper
surface of the lava-stream at a perpendicular elevation of
711 feet, we turned to the white ash cone, on which, from
its great steepness, we could not but fear that during fre-
quent and rapid slips we might be seriously wounded by the
rugged lava. The upper margin of the crater, on the south
western part of which we placed the instruments, forms
a ring of a few feet in width. We carried the barometer
from the margin into the oval crater of the truncated cone.
At an open fissure air streams forth of a temperature of
200°'6. We now stood 149 feet in perpendicular height
below the margin of the crater ; and the deepest point of
the chasm, the attainment of which we were compelled to
give up on account of the dense sulphurous vapours, ap-
peared to be only about twice this depth. The geognostic
discovery which had the most interest for us, was the find-
ing of several white fragments, three or four inches in dia-
meter, of a rock rich in felspar baked into the black basaltic
lava. I regarded these at first" as syenite, but from the

12 " M. Bonpland and myself were particularly astonished at finding,
encased in the basaltic, lithoid and scorified lavas of the volcano of
Jorullo, white or greenish white angular fragments of Syenite, com-
posed of a little amphibole and a great quantity of lamellar felspar.
Where these masses have been split by heat, the felspar has become
filamentous, so that the margins of the crack are united in some places
by fibres elongated from the mass. In the Cordilleras of South
America, between Popayan and Almaguer, at the foot of the Cerro
Broncoso, I have found actual fragments of gneiss encased in a trachyte
abounding in pyroxene. These phenomena prove that the trachytic
formations have issued from beneath the granitic crust of the globe.
Analogous phenomena are presented by the trachytes of the Siebenge-
Mrge on the banks of the Khine, and by the inferior strata of Phono-
lite (Porphyrschiefer) of the Biliner Stein in Bohemia." (Humboldt,
Essai Geognostique sur le Gisement des Roches, 1823, pp. 133 and 339.
Burkart also (Aufenthalt und Reisen in Mexico, Bd. i, s. 230) detected
enclosed in the black lava, abounding in olivine, of Jorullo : " Blocks
of a metamorphosed syenite. Hornblende is rarely to be recognized
distinctly. The blocks of syenite may certainly furnish an incontro-
vertible proof, that the seat of the focus of the volcano of Jorullo is
either in or below the syenite, which shows itself in considerable
extent, a few miles (leguas) further south, on the left bank of the Rio
de las Balsas, flowing into the Pacific Ocean." Dolomieu, and, in 1832,
the excellent geognosist, Friedrich Hoffmann, found in Lipari, neai

TRUE VOLCANOES. 321

exact examination by Gustav RO-SP, of a fragment which I
brought with me, they prohably belong rather to the granite
formation, which Bnrkart has also seen emerging from
below the syenite of the Rio de las Balsas. " The inclosure
is a mixture of quartz and felspar. The blackish green spots
appear to be not hornblende, but mica fused with some
felspar. The white fragment baked in is split by volcanic
heat, and in the crack white, tooth-like, fused threads run
from one margin to the other."

To the north of the great volcano and the scoriaceous
lava mountain which it has vomited forth in the direction
of the old basalt of the Cerro del Mortero, follow the two
last of the six often-mentioned eruptions. These hills also
were originally very active, for the people still call the ex-
treme mountain of ashes, el Volcancito. -A. broad fissure
opened towards the west, bears the traces of a destroyed
crater. The great volcano, like the Epomeo in Ischia, ap-
pears to have only once poured out a mighty lava-stream.
That its lava-pouring activity endured after the period 01
its first eruption, is not proved historically ; for the valuable
letter, so happily discovered, of Father Joaquin de Ansogorri,
written scarcely three weeks after the first eruption, treats
almost exclusively of the means of making " arrangements
for the better pastoral care of the country people who had
fled from the catastrophe and become dispersed ;" and for the
following thirty years we have no records. As the tradition
speaks very generally of fires which covered so great a sur-
face, it is certainly to be supposed that all the six hills upon
the great fissure, and the portion of the Malpais itself in
which the Hornitos have appeared, were simultaneously in
combustion. The temperature of the surrounding air, which
I measured, allows us to judge of the heat which prevailed
there 43 years previously ; they remind one of the former
condition of our planet, in which the temperature of its
atmospheric envelope, and with this the distribution of
organic life, might be modified by the thermic action of the
interior by means of deep fissures (under any latitude and
for long periods of time).

Caneto, fragments of granite, formed of pale red felspar, black mica,
and a little pale gray quartz, enclosed in compact masses of obsidiau
(Poggendorfl's Annalen der Physik, Bd. xxvi, s. 49).

VOL. V. Y

322 COSMOS.

Since I described the Hornitos which surround the vol*
cano of Jorullo, many analogous platforms in various regions
of the world, have been compared with these oven-like little
hills, To me, the Mexican ones, from their interior con-
formation, appear still to stand in a very contrasting and
isolated condition. If all upheavals which emit vapours are
to be called eruptive -cones, the Hornitos certainly deserve
the appellation of Fumaroles. But the denomination, erup-
tive-cones, would lead to the erroneous notion that there is
evidence that the Hornitos have thrown out scoriae, or even,
like many eruptive-cones, poured forth lava. Yery different,
for example (to advert to a great phenomenon) are the three
chasms in Asia Minor, upon the former boundaries of Mysia
and Phrygia, in the ancient burning country (Katake-
kaumene) " where it is dangerous to dwell (on account of
the earthquakes)," which Strabo calls (fivaai, or wind-bags,
and which the meritorious traveller, William Hamilton, has
rediscovered.13 Eruptive cones such as are exhibited by the
island of Lancerote near Tinguaton, or by Lower Italy, or
(ot hardly 20 feet in height) by the declivity of the great
Kamtschatkan volcano, Awatscha,14 which was ascended in
July, 1824, by my friend and Siberian companion, Ernst
Hofmann, consist of scoriae and ashes surrounding a small
crater, which has thrown them out, and has been in return
buried by them. In the Hornitos nothing like a crater is to
be seen, and they consist — and this is an important charac-
ter— merely of basaltic balls, with shell-like separated frag-
ments, without any admixture of loose angular scoriae. At
the foot of Vesuvius, during the great eruption of 1794 (and

15 Strabo, lib. xiii, pp. 579 and 628 ; Hamilton, Researches in Asia
Minor, vol. ii, chap. 39. The most western of the three cones, now
called Kara Devlit, is raised 532 feet above the plain, and has emitted
a great lava-stream in the direction of Koula. Hamilton counted more
than thirty small cones in the vicinity. The three chasms (fioOpw and
<j>vaai of Strabo) are craters situated upon conical mountains composed
of scorice and lavas.

14 Erman, Reiseum die JSrde, Bd. iii, s. 538 ; Cosmos, vol. v, p. 248,
Postels ( Voyage autour du Monde par le Cap. Lutke, partie hist. fc. iii,
p. 76) and Leopold von Buch (.Description Physique des lies Canaries,
p. 448) mention the similarity to the Hornitos of Jorullo. In a manu-
script most kindly communicated to me, Erman describes a great
number of truncated cones of scoriae in the immense lava-field to the
east of the Baidar Mountains on the peninsula of Kamtschatka.

TRUE VOLCANOES. 323

also in earlier times), eight different, small craters of erup-
tion, (bocche nuove) were formed, arranged upon a longitu-
dinal fissure ; they are the so-called parasitic cones of erup-
tion, which poured forth lava, and are even by this circum-
stance entirely distinct from the Hornitos of Jorullo.
" Your Hornitos," wrote Leopold von Buch to me, " are
not cones accumulated by erupted matters ; they have been
upheaved directly from the interior of the earth." The
production of the volcano of Jorullo itself was compared by
this great geologist with that of the Monte Nuovo in the
Phlegrsean fields. The same notion of the upheaval of six
volcanic mountains upon a longitudinal fissure forced itself
as the most probable upon Colonel Riano and the mining
commissary Fischer in 1789 (see ante, p. 313), upon myself
at the first glance in 1803, and upon Burkart in 1827.
With both the new mountains, produced in 1538 and 1759,
the same questions repeat themselves. Upon that of South-
ern Italy, the testimonies of Falconi, Pietro Griacomo di
Toledo, Francesco del Nero and Porzio, are circumstantial,
near the time of the catastrophe and prepared by educated
observers. The celebrated Porzio, who was the most
learned of these observers, says : — "Magnus terrse tractus,
qui inter radices montis, quern Barbarum incolae appellant,
et mare juxta Avernum jacet, sese erigere videbatur et montis
subito nascentis figuram iinitari. Iste terras cumulus aperto
veluti ore magnos ignes evomuit, pumicesque et lapides,
cineresque." 15

From the geognostic description here completed of the
volcano of Jorullo, we will pass to the more eastern parts
of Central Mexico (Anahuac). Unmistakeable lava-streams,
the principal mass of which is usually basaltic, have been
poured out by the peak of Orizaba according to the most recent,

15 Porzio, Opera omnia, Med., Phil, et Mathem. in unum collect a,
1736: according to Dufre*noy, Memoires pour servir a une Description
Geologique de la France, t. iv, p. 272. All the genetic questions are
discussed very completely and with praiseworthy impartiality in the
9th edition of Sir Charles Lyell's Principles of Geology, 1853, p. 369.
Even Bouguer (Figure de la Terre, 1749, p. Ixvi) was not disinclined
to the idea of the upheaval of the volcano of Pichincha. He says : —
" It is not impossible that the rock, which is burnt and black, may
have been elevated by the action of subterranean fire." See also
p. xci.

Y *

324 COSMOS.

interesting observations of Pieschel (March, 1854)leand H.
de Saussure. The rock of the peak of Orizaba, like that of the
volcano of Toluca17 which I ascended, is composed of horn-
blende, oligoclase, and a little obsidian; whilst the funda-
mental mass of Popocatepetl is a Chimborazo-rock, composed
of very small crystals of oligoclase and augite. At the foot of
the eastern slope of Popocatepetl, westward of the town
la Puebla de los Angeles, in the Llano de Tetimpa, where I
measured the base for the determination of the elevation of
the two great Nevados (Popocatepetl and Iztaccihuatl)
which bound the valley of Mexico, I found, at a height
of 7000 feet above the sea, an extensive and myste-
rious kind of lava-field It is called the Malpais (rough
rubbish-field) of Atlachayacatl, a low trachytic dome, on
the declivity of which the river Atlaco rises and runs at
an elevation of from 60 to 85 feet above the adjacent plain,
from east to west, and consequently at right angles to the
volcanoes. From the Indian village of San Nicolas de
los Ranchos, to San Buenaventura, I calculated the length
of the Malpais at more than 19,200 feet, and its breadth at
6400 feet. It consists of black, partially upraised lava-
blocks of a fearfully wild appearance, and only sparingly
coated here and there with lichens, contrasting with the yel-
lowish white coat of pumice-stone which covers everything
for a long distance round. The latter consists here of coarsely
fibrous fragments of two or three inches in diameter, in
which hornblende crystals sometimes lie. This coarser
pumice-stone sand, is different from the very finely granular
sand, which, near the rock el Frayle and at the limit of per-
petual snow, on the volcano Popocatepetl, renders the ascent
so dangerous, because, when it is set in motion on steep decli-
vities, the sand-mass, rolling down, threatens to overwhelm
everything. Whether this lava field of fragments (in
Spanish JUalpais, in Sicily Sciarra viva, in Iceland Odaada-
Ilraun,} is due to ancient lateral eruptions of Popocate-
petl, situated one above the other, or to the somewhat
rounded cone of Tetlijolo (Cerro del Corazon de Piedra) I

16 Zeitschrift fur Allgemeine Erdkunde, Bd. iv, s. 398.

1' For the more certain determination of the minerals of which the
Mexican volcanoes are composed, old and recent collections made
by myself and Pieschel have been compared.

TRUE VOLCANOES. 325

cannot determine. It is also geognostically remarkable that,
further to the east, on the road towards the small fortress
Perote, the ancient Aztec Pinahuizapan, between Ojo de
Agua, Yenta de Soto and el Portachuelo, the volcanic forma-
tion of coarsely fibrous, white, friable perlite 18 rises
beside a limestone (Marmol de la Puebla) which is probably
tertiary. This perlite is very similar to that of the conical
hill of Zinapecuaro (between Mexico and Valladolid) ; and
contains, bet-ides laminae of mica, and lumps of immersed
obsidian, a glassy, bluish- gray, or sometimes red, jasper-like
streaking. The wide " perlite district " is here covered with
a finely granular sand of weathered perlite, which might be
taken, at the first glance, for granitic sand, and which, not-
withstanding its allied origin, is still easily distinguishable
from the true, grayish white pumice-stone sand. The latter
is more proper to the immediate vicinity of Perote, — the pla-
teau 7460 feet in height between the two volcanic chains of
Popocatepetl and Orizaba, which strike north and south.

When, on the road from Mexico to Yera Cruz, we begin
to descend from the heights of the non-quartzose, trachytic
porphyry of the Yigas towards Canoas and Jalapa, we again
twice pass over fields of fragments and scoriaceous lava : —
the first time between the station Parage de Garros and Canoas
or Tochtlacuaya, and the second, between Canoas and the
station Casas de la Hoya. The first point is called Loma de
Tobias on account of the numerous upraised, basaltic blocks
of lava containing abundance of olivine ; the second simply
el Malpais. A small ridge of the same trachytic porphyry,
full of glassy felspar, which forms the eastern limit of the
Arenal (the perlitic sand-fields) near la Cruz Blanca
and Rio Frio (on the western declivity of the heights of
las Yigas) separates the two branches of the lava-field
which have just been mentioned, — the Loma de Tablas, and
the much broader Malpais. Those of the country people
who are well acquainted with the district assert that the
band of scoriae is elongated towards the south-south-east,
and consequently towards the Cofre de Perote. As I have

18 The beautiful marble of la Puebla comes from the quarries of
Tecali, Totomehuacan and Portachuelo, to the south of the high
trachytic mountain, el Pizarro. I have also seen limestone cropping
out near the terrace-pyramid of Cholula, on the way to la Puebla.

326 COSMOS.

myself ascended the Cofre and made many measurements
on it,19 I have been but little inclined to conclude, from a
19 The Cofre de Perote stands nearly isolated to the south-east of
the Fuerte or Castillo de Perote, near the eastern slope of the
great plateau of Mexico; but its great mass belongs to an impor-
tant range of heights, which, forming the margin of the slope,
extends in a north and south direction, from Cruz Blanca and Rio
Frio towards las Vigas (lat. 19° 37' 37") past the Cofre de Perote
(lat. 19° 28' 57", long. 97° 7' 20") to the westward of Xicochimalco
and Achilchotla to the Peak of Orizaba (lat. 19° 2' 17", long.
97° 13' 56"), parallel to the chain (Popocatepetl — Iztaccihuatl)
which separates the cauldron-valley of the Mexican lakes from
the plain of la Puebla. (For the grounds of these determinations
see my Recueil d'Observ. Astron, vol. ii, pp. 529—532 and 547, and
also Analyse de I 'Atlas du Mexique, or Essai Politique sur la Nou-
velle Espagne, t. i, pp. 55 — 60). As the Cofre has raised itself
abruptly in a field of pumice-stone many miles in width, it appeared
to me in my winter ascent (the thermometer fell at the summit, on
the 7th February, 1804, to 28°'4) to be extremely interesting, that
the covering of pumice-stone, the thickness and height of which I
measured barometically at several points both in ascending and de-
scending, rose more than 780 feet. The lower limit of the pumice-
stone, in the plain between Perote and Rio Frio, is 1187 toises (7590
i'eet) above the level of the sea ; the upper limit on the northern
declivity of the Cofre 1309 toises (8370 feet); thence through the
Pinahuast, the Alto de los Caxones (1954 toises = 12,4 96 feet), where I
could determine the latitude by the sun's meridian altitude up to the
summit itself, no trace of pumice-stone was to be seen. During the
upheaval of the mountain, a portion of the coat of pumice-stone of
the great Arenal, which has probably been levelled in strata by water,
was carried up. I inserted a drawing of this zone of pumice-stone
in my journal (February, 1804) on the spot. It is the same impor-
tant phenomenon which was described by Leopold von Buch in the
year 1834 on Vesuvius, where horizontal strata of pumice-tufa were
raised by the elevation of the volcano to a greater height indeed,
1900 or 2000 feet towards the Hermitage del Salvatore (Pog-
gendorfs Annalen, Bd. xxxvii, s. 175 — 179). The surface of
the dioritic trachyte rock on the Cofre, at the point where I found
the highest pumice-stone, was not withdrawn from observation by
snow. The limit of perpetual snow lies in Mexico under the latitudes
of 19° or 191°, only at the average elevation of 2310 toises (14,770
feet), and the summit of the Cofre, up to the foot of the small, house-
like cubical rock where I set up the instruments, reaches 2098
toises, or 13,418 feet above the sea level. According to angles of
altitude the cubical rock is 21 toi.ses or 134 feet in height ; conse-
quently the total altitude, which cannot be reached on account of
the perpendicular wall of the rock is 13,552 feet above the sea. I
found only single spots of sporadic snow, the lower limit of which
was 12,150 feet; about 700 or 800 feet below the upper limit of

TRUE VOLCANOES. 327

prolongation of the lava-stream which is certainly very pro-
bable (it is so represented in my Profiles tab. 9 and 11, and
in the Nivellement Barometrique), that it may have flowed
from this mountain, the form of which is so remarkable.
The Cofre de Perote, which is nearly 1400 feet higher than
the peak of Teneriffe, but inconsiderable in comparison with
the giants Popocatepetl and Orizaba, forms, like Pichincha,
a long rocky ridge, upon the southern extremity of which
stands the small cubical rock (la Pen a), the form of which
gave origin to the ancient Aztec name of Nauhcampatepetl.
In ascending the mountain I saw no trace of the falling in
of a crater, or of eruptive orifices on its declivities ; no
masses of scoriae, and no obsidians, perlites or pumice-stones
belonging to it. The blackish gray rock is very uniformly
composed of much hornblende and a species of felspar, which
is not glassy felspar (sanidinr) but oligoclase ; this would
show the entire rock, which is not porous, to be a dioritic
trachyte. I describe the impressions which I experienced.

forest-trees in beautiful pine-trees : Pinus occidentalis, mixed with
Cupressus sabinoides and Arbutus Madrono. The oak, Quercus xala-
pensis, had accpmpanied us only to an absolute elevation of 10,340
feet. (Humboldt, Nivellement barometr. des Cordilleres, Nos. 414 —
429). The name of Nauhcampatepetl, which the mountain bears in
the Mexican language, is derived from its peculiar form, which also
induced the Spaniards to give it the name of Cofre. It signifies
" quadrangular mountain" for nauhcampa, formed from nahui, the
numeral four, signifies, as an adverb from four sides, but as an adjec-
tive (although the Dictionaries do not state this), undoubtedly quad-
rangular or four -sided, as this signification is attached to the com-
pound nauhcampa ixquich. An observer, very well acquainted with
the country, M. Pieschel, supposes the existence of an old crater-
opening on the eastern declivity of the Cofre de Perote (Zeitschrift
filr Allgem. Erdkunde, herausg, von Gumprecht, Bd. v, s. 125). I
drew the view of the Cofre, given in my Vues des Cordilleres, pi. xxxiv,
in the vicinity of the castle of San Carlos de Perote, at a distance of
about eight miles. The ancient Aztek name of Perote was Pinahui-
zapan, and signifies (according to Buschmann) the beetle pinaJiuiztli
(regarded as an evil omen, and employed superstitiously in fortune-
telling : see Sahagun, Historia Gen. de las Cosas de Nueva Espana,
t. ii, 1829, pp. 10 — 11) on the water ; the name of this beetle is derived
from pinahua, to be ashamed. From the same verb is derived the
above-mentioned local name Pinahuast (pinahuaztli) of this district;
as well as the name of a ehrub (Mimosaceae '?) pinahuihuiztli, trans-
lated herba verecunda by Hernandez, the leaves of which fall down
when touched.

328 COSMOS.

If the terrible, black lava-field — Malpais — (upon which I
have here purposely dwelt in order to counteract the too
one-sided consideration of exertions of volcanic force from
the interior), did not flow from the Cofre de Perote itself at a
lateral opening, still the upheaval of this isolated mountain
13,553 feet in height, may have caused the formation of the
Loma de Tablas. During such an upheaval, longitudinal
fissures and networks of fissures may be produced far and
wide by folding of the soil, and from these, molten masses
may have poured directly, sometimes as dense masses, and
sometimes as scoriaceous lava, without any formation of true
mountain platforms (open cones or craters of elevation).
Do we not seek in vain in the great mountains of basalt and
porphyritic-slate, for central points (crater-mountains) or lower,
circumvallated, circular chasms, to which their common pro-
duction might be ascribed ? The careful separation of that
which is genetically different in phenomena : — the forma-
tion of conical mountains with permanently open craters
and lateral openings ; of circumvallated craters of elevation
and Maars ; of upraised closed bell-shaped mountains or open
cones, or matters poured out from coalescent fissures —
is a gain to science. It is so because the multiplicity of
opinions which is necessarily called forth by an enlarged
ho-izon of observation, and the strict critical comparison of
that which exists, with that which is asserted to be the
only mode of production, are most powerful inducements
to investigation. Even upon European soil, however, on the
island of Eubcea, so rich in hot springs, a vast lava-stream
has been poured out,80 within the historical period, from
a chasm in the great plain of Lelanton, at a distance from
any mountain.

In the volcanic group of Central America, which follows
the Mexican group towards the south, and in which eighteen
conical and bell-shaped mountains may be regarded as still
active, four (Nindiri, el Nuevo, Conseguina, and San Miguel
de Bosotlan) have been recognized as producing lava.81 The
mountains of the third volcanic group, that of Popayan and
Quito, have already for more than a century enjoyed the re-

20 Strabo, lib. i, p. 58, lib. vi, ,». 269, ed. Casaubon; Cosmos, vol. i,
p. 236, and vol. v, p. 225.
31 See page 278.

TRUE VOLCANOES. 329

putati^n of furnishing no lava-streams, but only incoherent,
glowing scoriaceous masses, thrown out of the single summital
crater, and often rolling down in a linear arrangement. This
was even the opinion22 of La Condamine, when he left the
highlands of Quito and Cuen$a in the spring of 1743. Four-
teen years afterwards, when he returned from an ascent of
Vesuvius (4th June, 1755), in which he accompanied the
sister of Frederick the Great, the Margravine of Baireuth,
he had the opportunity of expressing himself warmly, in a
meeting of the French Academy, upon the want of true
lava-streams (laves coulees par torrens de matieres liquefiees)
22 " I have never known," says La Condamine, "lava-like matter in
America, although M. Bouguer and myself have encamped for whole
weeks and months upon the volcanoes, and especially upon those of
Pichincha, Cotopaxi, and Chimborazo. Upon these mountains I have
only seen traces of calcination, without liquefaction. Nevertheless, the
kind of blackish crystal, commonly called Piedra de Gallinafo in Peru
(obsidian), of which I have brought home several fragments, and of
which a polished lens of seven or eight inches in diameter, may be seen
in the cabinet of the Jardin du Roi, is nothing but a glass formed
by volcanic action. The materials of the stream of fire which flows
continually from that of Sangai, in the province of Macas, to the south-
east of Quito, are no doubt lava, but we have only seen this mountain
from a distance, and I was no longer at Quito at the time of the last
eruptions of the volcano of Cotopaxi, when vents opened upon its
flanks, from which ignited and liquid matters were seen to issue in
streams, which must have been of a similar nature to the lava of
Vesuvius" (La Condamine, Journal de Voyage en Italic, in the
Hemoires de VAcad. des Sciences, 1757, p. 357, Historic, p. 12). The
two examples, especiallythe first, are not happily chosen. The Sangay
was first scientifically examined in December of the year 1849, by
Sebastian Wisse ; what La Condamine, at a distance of 108 miles,
took for luminous lava flowing down, and "an effusion of burning
sulphur and bitumen," consists of red-hot stones and scoriaceous
masses, which sometimes, pressed closely together, slip down on the
steep declivities of the cone of ashes (Cosmos, see above, p. 264). On
Cotopaxi, as on Tungurahua, Chimborazo, and Pichincha, or on
Purace, and Sotara near Popayan, I have seen nothing that could be
looked upon as narrow lava-streams, which had flowed from these
colossal mountains. The incoherent, glowing masses of 5 — 6 feet in
diameter, often containing obsidian, which Cotopaxi has scattered
abroad during its eruptions, impelled by floods of melting snow and
ice, have reached far into the plain, where they form rows partially
diverging in a radiate form. La Condamine also says very truly else-
where (Journal du Voyage a T Equateur, p. 160): — '''These fragments of
rock, as large as the hut of an Indian, form series of rays, which start
from the volcano as from a common centre."

330 COSMOS.

from the volcanoes of Quito. The Journal d'uti Voyage en
Italie, which was read at the meeting of the 20th April,
1757, only appeared in 1762 in the Memoires of the Aca-
demy of Paris, and is of some geognostic importance in the
history of the recognition of old extinct volcanoes in France,
because in this journal, La Condamine, with his peculiar
acuteness, and without knowing of the certainly earlier ob-
servations of Guettard,23 expresses himself very decidedly
upon the existence of ancient crater-lakes and extinct vol-
canoes in middle and northern Italy and in the south
of France.

This remarkable contrast between the narrow and un-
doubted lava-streams of Auvergne thus early recognized,
and the often too absolutely asserted absence of any effusion
of lava in the Cordilleras, occupied me seriously during the
whole period of my expedition. All my journals are full of
considerations upon this problem, the solution of which I
long sought in the absolute elevation of the summits and in
the vastness of the circumvallation, that is to say, the sink-
ing of trachytic conical mountains from mountain-plains of
eight or nine thousand (8500—9600 English) feet in eleva-
tion and of great breadth. We now know, however, that a
volcano of Quito, 17,000 feet in height, which throws out
scoriae (that of Macas), is uninterruptedly much more
active than the low volcanoes Izaleo and Stromboli; we
know that the eastern dome-shaped and conical mountains,
Antisana and Sangay, have free slopes towards the plains of
the Napo and Pastaza ; and the western ones, Pichincha,
Iliniza, and Chimborazo, towards the affluents of the Pacific
Ocean. In many also the upper part projects without cir-
cumvallation eight or nine thousand feet above the elevated
plateaux. Moreover, all these elevations above the sea-level,
which is regarded, although not quite correctly, as the mean
elevation of the earth's surface, are certainly inconsiderable
as compared with the depth which we may assume to be
that of the seat of volcanic activity, and of the necessary
temperature for the fusion of rock-masses.

23 Guettard's memoir on the extinct volcanoes was read at the
Academy in 1752, consequently three years before La Condamine's
journey into Italy; but only printed in 1756, consequently during the
Italian travels of the astronomer.

TRUE VOLCANOES. 331

The only phenomena resembling narrow lava-eruptions
which I discovered in the Cordilleras of Quito, are those
presented by the colossal mountain Antisana, the height of
which I determined to be 19,137 feet (5833 metres), by a
trigonometrical measurement. As the structure furnishes
the most important criterion here, I will avoid the systematic
denomination lava, which confines the idea of the mode of
production within too narrow limits, and make use, but
quite provisionally, of the names "rock-debris " (Felstrum-
inern) or " detritus dykes" (Schuttivallen, trainees de masses
volcaniques). The mighty mountain of Antisana, at an ele-
vation of 13,458 feet, forms a nearly oval plain, more than
12,5(30 toises (79,950 feet) in long diameter, from which the
portion of the mountain covered with perpetual snow rises
like an island. The highest summit is rounded off and
dome-shaped. The dome is united by a short jagged ridge
with a truncated cone lying towards the north. In the
plateau, partly desert and sandy, partly covered with grass
(the dwelling-place of a very spirited race of cattle, which,
owing to the slight atmospheric pressure, easily expel blood
from the mouth and nostrils when excited to any great mus-
cular exertion), is situated a small farm (Hacienda), a single
house in which we passed four days in a temperature varying
between 38°'6and 48C*2. The great plain, which is bynomeans
circumvallated as in craters of elevation, bears the traces of an
ancient sea-bottom. The Laguna Mica, to the westward of the
Altos de la Moya, is to be regarded as the residue of the old
covering of water. At the margin of the limit of perpetual
snow, the Rio Tinajillas bursts forth, subsequently, under the
name of Rio de Quixos, becoming a tributary of the Maspa,
the Napo, and the Amazon. Two narrow, wall-like dykes, or
elevations, which I have indicated upon the plan of Anti-
sana, drawn by me, as coulees de laves, and which are called
by the natives Volcan de la Hacienda and Yana Yolcan
( Tana signifies black or brown in the Qquechhua language),
pass like bands from the foot of the volcano at the lower
margin of the perpetual snow-line, and extend, apparently
with a very moderate declivity, in a direction N.E. — S.W.,
for more than 2000 toises (12,792 feet) into the plain.
With very little breadth they have probably an elevation
of 192 to 213 feet above the soil of the Llanos de la Ha-

332 COSMOS.

cienda, de Santa Lucia, and del Cuvillan. Their declivities
are everywhere very rugged and steep, even at the extremi-
ties. In their present state they consist of conchoidal and
usually sharp-edged fragments of a black basaltic rock, with-
out olivine or hornblende, but containing a few small white
crystals of felspar. The fundamental mass has frequently a
lustre like that of pitch stone, and contains an admixture
of obsidian, which was especially recognizable in very
large quantity, and more distinctly, in the so-called Cueva de
Antisana, the elevation of which we found to be 15,942 feet.
This is not a true cavern, but a shed formed by blocks of
rock which had fallen against and mutually supported each
other, and which preserved the mountain cowherds and also
ourselves during a fearful hailstorm. The Cueva lies somewhat
to the north of the Yolcan de la Hacienda. In the two
narrow dykes, which have the appearance of cooled lava-
streams, the tables and blocks appear in part inflated like
cinders or even spongy at the edges, and in part weathered
and mixed with earthy detritus.

Analogous but more complicated phenomena are presented
by another also band-like mass of rocks. On the eastern
declivity of the Antisana, probably about 1280 feet per-
pendicularly below the plain of the Hacienda in the direction
of Pinantura and Pintac, there lie two small round lakes, of
which the more northern is called Ansango, and the southern
Lecheyacu. The former has an insular rock, and is sur-
rounded by rolled pumice-stone, a very important point.
Each of these lakes marks the commencement of a valley ; the
two valleys unite, and their enlarged continuation bears the
name of Volcan de Ansango, because from the margins of
the two lakes narrow lines of rock debris, exactly like
the two dykes of the plateau which we have described above,
do not, indeed, fill up the valley, but rise in its midsb like
dams to a height of 213 and 266 feet. A glance at the local
plan which I published in the " Geographical and Physical
Atlas" of my American travels (pi. 26), will illustrate these
conditions. The blocks are again partly sharp-edged, and
partly scorified and even burnt like coke at the edges. It is
a basaltic, black, fundamental mass, with sparingly scattered
glassy felspar ; some fragments are blackish brown and of a
dull pitch stone-like lustre. Basaltic as the fundamental mass

TRUE VOLCANOES. 333

appears, however, it is entirely destitute of the olivine which
occurs so abundantly on the Rio Pisque and near Gualla-
bamba, where 1 saw basaltic columns of 72 feet in height
And 3 feet thick, which contained both olivine and horn-
blende scattered in them. In the dyke of Ansango nume-
rous tablets, cleft by weathering, indicate porphvritic slates.
All the blocks have a yellowish gray crust from weathering.
As the detritus-ridge (called los derrumbamientos, la reven-
tnzon, by the natives, who speak Spanish), may be traced
from the Eio del Molina, not far from the farm of Pintac,
up to the small crater-lakes surrounded by pumice-stone
(chasms filled with water), the opinion has grown up natu-
rally, and, as it were, of itself, that the lakes are the openings
from which the blocks of stone came to the surface. A few
years before my visiting the district, the ridge of fragments
was in motion for weeks upon the inclined surface, without
any perceptible previous earthquake, and some houses near
Pintac were destroyed by the pressure and shock of the
blocks of stone. The detritus-ridge of Ansango is still with-
out any trace of vegetation, which is found, although very
sparingly, upon the two more weathered and certainly older
eruptions of the plateau of Antisana.

How is this mode of manifestation of volcanic activity,
the action of which I am describing, to be denominated?24
Have we here to do with lava-streams ? or only with semi-
scorified and ignited masses, which are thrown out uncon-
nected, but in chains pressed closely upon each other (as on
Cotapaxi in very recent times)? Have the dykes of Yana
Volcan and Ansango been perhaps merely solid fragmentary
masses, which burst forth without any fresh elevation of
temperature from the interior of a volcanic conical mountain,
in which they lay loosely accumulated and therefore badly
supported, their movement being caused by the concussion
of an earthquake, impelled by shocks or falls and giving rise
to small local earthquakes ? Is no one of the three manifes-

24 " There are few volcanoes in the chain of the Andes," says Leopold
von Buch, "which have presented streams of lava, and none have
ever been seen around the volcanoes of Quito. Antisana, upon the
eastern chain of the Andes, is the only volcano of Quito upon whii/j
M. de Huniboldt saw, near the summit, something analogous to 7
stream of lava ; this stream was exactly like obsidian" (Descr. dea II*
Canaries, 1836, pp. 468 and 488).

334 COSMOS.

tations of volcanic activity here indicated, different as they
are, applicable in this case ? and have the linear accumula-
tions of rock-detritus been upheaved upon fissures in the
spots where they now lie (at the foot and in the vicinity of
a volcano)? The two dykes of fragments, in this so slightly
inclined plateau, called Volcan de la Hacienda and Yana
Volcan, which I once considered, although only conjecturally,
as cooled lava-streams, now appear to me, as far as I can
remember, to present but little in support of the latter opi-
nion. In the Yolcan de Ansango, where the line of frag-
ments may be traced without interruption, like a river-bed,
to the pumice margins of two small lakes, the fall, or differ-
ence of level between Pinantura 1482 toises (9476 feet), and
Lecheyacu 1900 toises (12,150 feet), in a distance of about
7700 toises (49,239 feet), by no means contradicts what we
now believe we know of the small average angles of inclina-
tion of. lava-streams. Prom the difference of level of 418
toises (2674 feet), there is an inclination of 3° 6'. A partial
elevation of the soil in the middle of the floor of the valley
would not appear to be any hindrance, because the back
swell of fluid masses impelled up valleys has been ob-
served elsewhere, for example, in the eruption of Scaptar
Jokul in Iceland, in 1783 (Naumann, Geognosie, Bd. i,
s. 160).

The word lava indicates no peculiar mineral composition
of the rock ; and when Leopold von Buch says that every-
thing is lava that flows in the volcano and attains new posi-
tions by its fluidity, I add that that which has not again be-
come fluid, but is contained in the interior of a volcanic
cone, may change its position. Even in the first description2*
of my attempt to ascend the summit of Chimborazo (only
published in 1837, in Schumacher's Astronomisclie Jahr-
buch), I expressed this opinion in speaking of the remarkable
"fragments of augitic porphyry which 1 collected on the
23rd June, 1802, in loose pieces of from twelve to fourteen
inches in diameter, upon the narrow ridge of rock leading
to the summit at an elevation of 19,000 feet. They
had small, shining cells, and were porous and of a red
colour. The blackest of them are sometimes light like
pumice-stone, and as though freshly altered by fire. They
25 Humboldt, Kldnere Sclirijten, Bd. i, s. 161.

TRUE VOLCANOES. 335

have not, however, flowed out in streams like lava, but have
probably been expelled at fissures on the declivity of the
previously upheaved, bell-shaped mountain." This genetic
explanation might find abundant support in the assumptions
of Boussingault, who regards the volcanic cones themselves
" as an accumulation of angular trachytic fragments, upheaved
in a solid condition, and heaped up without any order. As
after the upheaval the broken rocky masses occupy a greater
space than before they were shattered, great cavities remain
amongst them, movement being produced by pressure and
shock (the action of the volcanic vapour-force being ab-
stracted)." I am far from doubting the partial occurrence of
such fragments and cavities, which become filled with water
in the Nevados, although the beautiful, regular, and, for the
most part, perfectly perpendicular trachytic columns of the
Pico de los Ladrillos, and Tablahuma on Pichincha, and,
above all, over the small basin. Yana-Cocha on Chimborazo,
appear to me to have been formed on the spot. My old
and valued friend, Boussingault, whose chemico-geognostic
and meteorological opinions I am always ready to adopt,
regards what is called the Yolcan de Ansango, and what
now appears to me as an eruption of fragments from two
small lateral craters (on the western Antisana. below Chus-
sulongo) as upheavals of blocks20 upon long fissures. As
26 « \ye differ entirely with regard to the pretended stream of
Antisana towards Pinantura. I regard this stream (coulee] as a recent
upheaval analogous to those of Calpi (Yana Urcu). Pisque, and Jorullo.
The trachytic fragments have acquired a greater thickness towards the
middle of the stream. Their stratum is thicker towards Pinantura
than at points nearer Antisana. The fragmentary condition is an
effect of local upheaval, and in the Cordillera of the Andes earth-
quakes may often be produced by heaping up " (letter from M. Bous-
eingault, dated August, 1834). See page 270. In the description
of his ascent of Chimborazo (December, 1831), Boussingault says :
— " The mass of the mountain consists, in my opinion, of a
heap of trachytic ruins piled up on each other without any order.
These trachytic fragments of a volcano, which are often of enormous
size, are upheaved in the solid state ; their edges are sharp, and nothing
indicates that they had been in a fused or even a softened condition.
Nowhere, on any of the equatorial volcanoes, do we observe anything
that would allow us to infer a lava-stream. Nothing has ever been
thrown out from these craters except masses of mud, elastic fluids and
ignited, more or less scorified trachytic blocks, which have frequently
been scattered to considerable distances" (Hurnboldt, Kleinere Schriftent

336 COSMOS.

he has acutely investigated this region 30 years after myself
he insists upon the analogy which appears to him to be
presented by the geognostic relations of the eruption of
Ansango to Antisana, and those of Yana Urcu (of which
I made a particular plan) to Chimborazo. I was the less
inclined to believe in a direct upheaval upon fissures through-
out the entire linear extent of the tract of fragments at
Ansango, because this, as I have already repeatedly mentioned,
leads at its upper extremity, to the two chasms now filled
with water. Non-fragmentary, wall-like upheavals of great
length and uniform direction, are however not unknown to
me, as I have seen and described them in our hemisphere,
in Chinese Mongolia, in granite banks with a floetz-like
bedding27.

Antisana had an eruption28 in the year 1580, and
another in the beginning of the last century, probably in
1728. Near the summit, on the north»north-east side, we
observe a black mass of rock, upon which even freshly
fallen snow does not adhere. At this point, a black column
of smoke was seen ascending for several days in the spring
of 1801, at a time when the summit was on all sides per-
fectly free from clouds. On the 16th March, 1802, Bon-
pland, Carlos Montufar, and myself reached a ridge of
rock, covered with pumice-stone, and black, basaltic scoriae
in the region of perpetual snow, at an elevation of 2837
toises (18,142 feet), and consequently 2358 feet higher than
Montblanc. The snow was firm enough to bear us on

Bd. i, s. 200). With regard to the first origin of the opinion of the
upheaval of solid masses in the form of heaped-up blocks, see Acosta,
in the Viajes d los Andes Ecuatoriales par M. Boussingault, 1849,
pp. 222 — 223. The movement of the heaped-up fragments, induced by
earth-shocks and other causes, and the gradual filling up of the inter-
stices, may, according to the assumptions of the celebrated traveller,
produce a gradual sinking of volcanic mountain peaks.

^ Humboldt, Asie Centrale, t. ii, pp. 296—301 (Gustav Rose, mineral-
geognostische JReise nach dem Ural, dem Altai und dem Kasp. Meere,
Bd. i, s. 599). Narrow, much elongated granitic walls may have risen,
during the earliest foldings of the earth's crust, over fissures analo-
gous to the remarkable, still open ones, which are found at the foot of
the volcano of Pichincha: as the Guaycos of the city of Quito, of 30 —
40 feet in width (see my Kleinere Schriften, Bd. i, s. 24).

28 La Gondamine, Mesure des trois premiers Degr$s du Meridien dant
¥ Hemisphere Austral, 1751, p. 56.

TRUE VOLCANOES. 337

many points near the ridge of rock, which is so rare under
the tropics (temperature of the atmosphere, 280>8 — 34°'5).
On the southern declivity, which we did not ascend, at the
Piedro de Azufre, where scales of rock sometimes separate
of themselves by weathering, masses of pure sulphur of
10 — 12 feet in length, and 2 feet in thickness, are found;
sulphurous springs are wanting in the vicinity.

Although in the eastern Cordillera the volcano of Anti-
sana, and especially its western declivity (from Ansango
and Pinantura, towards the village of Pedregal) is sepa-
rated from Cotopaxi by the extinct volcano of Passuchoa2'
with its widely distinguishable crater (la Peila), by the
Nevado Sinchulahua and by the lower Ruminaui, there is
still a certain resemblance between the rocks of the two
giants. From Quinche onwards the whole eastern chain
of the Andes has produced obsidian, and yet el Quinche,
Antisana, and Passuchoa belong to the basin in which the
city of Quito is situated ; whilst Cotopaxi bounds another
basin, that of Lactacunga, Hambato and Riobamba. The
small knot of mountains of the Altos of Chisinche sepa-
rates the two basins like a dam ; and what is remarkable

'x Passuchoa, separated by the farm el Tambillo from the Atacazo,
does not any more than the latter attain the region of perpetual snow.
The elevated margin of the crater, la Peila, has fallen in towards the
west, but projects towards the east like an amphitheatre. The tradi-
tion runs that at the end of the sixteenth century, the Passuchoa,
which had previously been active, ceased its manifestations of activity
on the occasion of an eruption of Pichincha, which proves the communi-
cation between the vents of the opposite eastern and western Cordilleras.
The true basin of Quito, closed like a dam, — on the north by a moun-
tain group between Cotocachi and Imbaburo, and on the south,
by the Altos de Chisinche (between 0° 20' N. and 0° 41' S.), is for the
most part divided longitudinally by the mountain ridges of Ichimbio
and Poingasi. To the eastward lies the valley of Puembo and Chillo ;
to the westward the plain of Inaquito and Turubamba. In the eastern
Cordillera follow from north to south, — Imbaburo, the Faldas de
Guamani, and Antisana, Sinchulahua, and the perpendicular, black
wall, crowned with turret-iike points, of Ruminaui (Stone-eye); in the
western Cordillera, Cotocachi, Casitagua, Pichincha, Atacazo, and
Corazon, upon the slopes of which blooms the splendid Alpine plant,
the red Ranunculus Gusmani. This has appeared to me to be the place
to give, in brief terms, a morphological representation, drawn from my
owii experience, of the form of a spot which is so important and
classical in respect to volcanic geology.

VOL. V. Z

338 COSMOS.

enough, considering its smallness, the waters of the nor-
thern slope of Chisinche pass by the Rios de San Pedro,
de Pito, and de Guallabamba into the Pacific, whilst those
Df the southern declivity flow through the Rio Alaques and
the Rio de San Felipe into the Amazons and Atlantic
Ocean. The union of the Cordilleras by mountain knots
and dykes (sometimes low, like the Altos just mentioned ;
sometimes equal to Mont Blanc in height, as on the road
over the Paso del Assuay) appears to be a more recent
and also a less important phenomenon than the upheaval
of the divided parallel mountain chain itself. As Cotopaxi,
the greatest of the volcanoes of Quito, presents much
analogy in its trachytic rock with the Antisana, so also
we again meet with the rows of blocks (lines of fragments)
which have already occupied us so long, even in greater
number upon the slopes of Cotopaxi.

It was especially our business when travelling to trace
these rows to their origin, or rather to the point where they
are concealed beneath the perpetual covering of snow. Wo
ascended upon the south-western declivity of the volcano
from Mulalo (Mulahalo), along the Rio Alaques, which is
formed of the Rio de los Bafios and the Rio Barrancas, up to
Pansache (12,066 feet), where we inhabited the spacious
Casa del Paramo in the grassy plain (el Pajonal). Although
up to this time much snow had fallen at night, we never-
theless got to the eastward of the celebrated Cabeza del
Inga, first into the Quebrada and Reventazoii de las Minas,
and afterwards still further to the east over the Alto de
Suniguaicu to the chasm of the Lion Mountain (Puma-
Urcu), where the barometer only showed an elevation of
2263 toises, or 14,471 feet. Another line of fragments
which, however, we only saw from a distance, has moved
from, the eastern part of the snow-clad ash-cone towards the
Rio Negro (an affluent of the Amazon) and Yalle vicioso. It
is uncertain whether these blocks were all thrown out of the
crater at the summit to a great height in the air, as glow-
ing, scoriaceous masses fused only at the edges (some angular,
some rounded, of 6 or 8 feet in diameter, rarely conchoidal
like those of Antisana), falling oil the declivity of Cotopaxi
and, hastened in their movement by the rush of the melted
snow water ; or whether, without passing through the air

TRUE VOLCANOES. 335

they were forced out through lateral fissures of the volcano,
as the word reventazon would indicate. Soon returning
from Suuiguaicu and the Quebrada del Vi estizo. we examined
the long and broad ridge which, striking from N.W. to S.E.,
unites Cotopaxi with the Nevado de Quelenclaila. Here the
blocks arranged in rows are wanting, and the whole appears to
be a darn-like upheaval, upon the ridge of which are situated
the small conical mountain el Morro and, nearer to the horse-
shoe shaped Quelendaria, seAreral marshes and two small
lakes (Lagunas de Yauricocha and de Verdecocha). The
rock of el Morro and of the entire linear volcanic upheaval
was greenish-gray porphyritic slate, separated into layers of
eight inches thick, which dipped very regularly towards the
east at 60°. Nowhere was there any trace of true lava-
streams?0.

30 It is particularly remarkable that the vast volcano of Coto-
paxi, which manifests an enormous activity, although, indeed, usually
only after long periods, and acts destructively upon the neighbour-
hood, especially by the inundations which it produces, exhibits no
visible vapours between its periodical eruptions, when seen either in the
plateau of Lactacunga, or from the Paramo de Pansache. From several
comparisons with other colossal volcanoes, such a phenomenon is
certainly not to be explained from its height of 19,180 feet, and the
great tenuity of the strata of air and vapour corresponding with this
elevation. No other Nevado of the equatorial Cordilleras shows
itself so often free from clouds and in such great beauty as the trun-
cated cone of Cotopaxi, that is to say the portion which rises above
the limit of perpetual snow. The uninterrupted regularity of this
ash-cone is much greater than that of the ash-cone of the Peak of
Teueriffe, on which a narrow projecting rib of obsidian runs down
like a wall. Only the upper part of the Tungurahua is said for-
merly to have been distinguished in an almost equal degree by the
regularity of its form, but the terrible earthquake of the 4th Feb-
ruary, 1797, called the Catastrophe of Riobamba, has deformed the
mountain cone of Tungurahua by fissures and the falling in of parts
and the descent of loosened wooded fragments, as also by the accu-
mulation of debris. At Cotopaxi, as even Bouguer observed, the
enow is mixed in particular spots with crumbs of pumice-stoue,
when it forms a nearly solid mass. A slight inequality in the
mantle of snow is visible towards the north-west, whei-e two fissure-
like valleys run down. Black rocky ridges ascending to the summit
are seen nowhere from afar, although in the eruptions of the 24th
Juno and 9th December, 1742, a lateral opening showed itself halfway
up the snow-covered ash-cone. " There opened," says Bouguer (Fiyui't.
de la Terre, p. Ixviii ; see also La Condarniue, Journal du Voyage a
I'EquatcUr, p. 159), " a new mouth towards the middle of the paii

Z2

340 COSMOS.

In the island of Lipari, which abounds in pumice-
stone, a lava-stream of pumice-stone and obsidian runs
constantly covered with, snow, whilst the flame always issued at the
top of the truncated cone." Quite at the top, close to the summit, some
horizontal, black streaks, parallel to each other, but interrupted, are
detected. When examined with the telescope under various illumi-
nations they appeared to me to be rocky ridges. The whole of this
upper part is steeper, and almost close to the truncation of* the cone
forms a wall-like ring of unequal height, which, however, is not
visible at a great distance with the naked eye. My description of this
nearly perpendicular uppermost circumvallation, has already attracted
the particular attention of two distinguished geologists, — Darwin ( Vol-
canic Islands, 1844, p. 83), and Dana (Geology of the U.S. Explor. Exped.,
1849, p. 356). The volcanoes of the Galapagos Islands, Diana's Peak
in St. Helena, Teneriffe, and Cotopaxi, present analogous formations.
The highest point which I determined by angles of altitude in the
trigonometrical measurement of Cotopaxi, was situated in a black
convexity. It is, perhaps, the inner wall of the higher and more
distant margin of the crater; or is the freedom from snow of the pro-
truding rock caused at once by steepness and the heat of the crater?
In the autumn of the year 1800, the whole upper part of the ash-
cone was seen to be luminous, although no eruption, or even emission
of visible vapours followed. On the other hand, in the violent erup-
tion of Cotopaxi on the 4th January. 1803, when during my residence
on the Pacific coast the thundering noise of the volcano shook the
windows in the harbour of Guayaquil (at a distance of 148 geog.
miles), the ash-cone had entirely lost its snow, and presented a
most threatening appearance. Was such a heating ever observed
before ? Even very recently, as we learn from that admirable, and
courageous female traveller, Ida Pfeiffer (Meine zweite Weltreise, Bd. iii,
s. 170), the Cotopaxi had, in the beginning of April, 1854, a violent
eruption of thick columns of smoke, "through which the fire wound
itself like flashing flames." May this luminous phenomenon have
been a consequence of the volcanic lightning excited by vaporization ?
The eruptions have been frequent since 1851.

The great regularity of the snow-covered, truncated cone itself,
renders it the more remarkable that to the south-west of the summit
there is a small, grotesquely-notched, rocky mass with three or four
points at the lower limit of the region of perpetual snow, where
the conical form commences. The snow remains upon it only in
small patches, probably on account of its steepness. A glance at my
representation (Atlas Pittoresque du Voyage, pi. 10), shows its relation
to the ash-cone most distinctly. I approached nearest to this blackish-
gray, probably basaltic rocky mass, in the Quebrada and Reventazon
de Minas. Although this widely visible hill, of very strange appear-
ance, has been generally known for centuries in the whole province
as the Cabeza del Inga, two very different hypotheses, nevertheless,
prevail with regard to its origin amongst the coloured aborigines
(fndios), — according to the one, it is merely asserted, that the rock

TRUE VOLCANOES. 341

down to the north of Caneto, from the well-preserved,
extinct crater of the Monte di Campo Bianco towards the
sea, in which the fibres of the former substance run, singu-
larly enough, parallel to the direction of the stream31. The

is the fallen summit of the volcano, which formerly ended in a point,
without any statement of the date at which the occurrence took
place; according to the second hypothesis, this is placed in the year
(1533) in which the Inca Atahuallpa was strangled in Caxamarca,
and thus connected with the terrible fiery eruption of Cotopaxi,
described by Herrera, which took place in the same year, and also
with the obscure prophecy of Atahuallpa's father, Huayna Capac,
regarding th« approaching fall of the Peruvian Empire. Is that
\vhich is common to both hypotheses, — namely, the opinion that this
fragment of rock formerly constituted the apex of the cone,— the tra-
ditional echo, or obscure remembrance of an actual occurrence ? The
aborigines, it may be said, in their uncultivated state, would probably
notice facts and preserve them in remembrance, but would be unable
to rise to geoguostic combinations. I doubt the correctness of this
objection. The idea that a truncated cone, " in losing its apex," may
have thrown it off unbroken, as large blocks were thrown out during
subsequent eruptions, may present itself even to very uncultivated
minds. The terraced pyramid of Cholula, a work of the Tolteks, is
truncated. The natives could not suppose that the pyramid was not
originally completed. They therefore invented the fable that an
aerolite, falling from heaven, destroyed the apex ; nay, portions of the
aerolite were shown to the Spanish conquerors. Moreover, how can we
place the first eruption of the volcano of Cotopaxi at a period when
the ash-cone (the result of a series of eruptions) was already in exist-
ence ? It seems probable to me, that that the Cabeza del Inga, was pro-
duced at the spot which it now occupies ; that it was upheaved there,
like the Yana-Urcu at the foot of Chimborazo, and like the Morro on
Cotopaxi itself, to the south of Suniguaica, and to the north-west of
the small lake Yurak-cocha (in the Qquechhua language, the White
Lake).

With regard to the name of the Cotopaxi, I have stated in the
first volume of my Kleinere Schriften, (s. 463,) that only the first pai-t
of it could be explained from the Qquechhua language, being the word
ccotto, heap or mass, but that pacsi was unknown. La Condamine
(p. 53) explains the whole name of the mountain, saying " in the lan-
guage of the Incas, the name signifies shining mass" Buachmann,
however, remarks that, in this case, pacsi is replaced by the word
pacsa, which is certainly quite different from it, and which signifies
lustre, brilliancy, especially the mild lustre of the moon ; to express
" shining mass," moreover, in accordance with the spirit of the
Qquechhua language, the position of the two words would have to be
reversed, — pacsaccotto.

31 Friedrich Hoffmann, in Poggendorff's Annalen, Bd. xxvi, 1832,
s. 48.

342 COSMOS.

extended pumice quarries, four miles and a half from Lao
tacunga, present, according to my investigation of the local
conditions, an analogy with this occurrence on Lipari. These
quarries, in which the pumice-stone, divided into horizontal
beds, has exactly the appearance of a rock in position, ex-
cited even the astonishment of Bouguer in 173732. "On vol-
canic mountains," he says, " we only find simple fragments
of pumice-stone of a certain size ; but at seven leagues to
the south of Cotopaxi; in a point which corresponds with
our tenth triangle, pumice-stone forms entire rocks, ranged in
parallel banks of 5 to 6 feet in thickness in a space of more
than a square league. Its depth is not known. Imagine
what a heat it must have required to fuse this enormous
mass, and in the very spot where it now occurs ; for it is
easily seen that it has not been deranged, and that it has
cooled in the place where it was liquefied. The inhabitants
of the neighbourhood have profited by this immense quarry,
for the small town of Lactacunga, with some very pretty
buildings, has been entirely constructed of pumice-stone, since
the earthquake which overturned it in 1698."

The pumice quarries are situated near the Indian vil-
lage of San Felipe, in the hills of Guapulo and Zumbalica,
which are elevated 512 feet above the plateau and 9990 feet
above the sea level. The uppermost layers of pumice-stone
are, therefore, five or six hundred feet below the level of
Mulalo, the once beautiful villa of the Marquis of Maenza
(at the foot of Cotopaxi), also constructed of blocks of
pumice-stone, but now completely destroyed by frequent
earthquakes. The subterranean quarries are at unequal
distances from the two active volcanoes, Tungurahua and
32 Bouguer, Figure de la Terre, p. Ixviii. How often, since the earth-
quake of the 19th July, 1698, has the little town of Lactacunga been
destroyed and rebuilt with blocks of pumice-stone from the subterra-
nean quarries of Zumbalica ! According to historical documents com-
municated to me during my sojourn in the country, from copies of the
old ones which have been destroyed, and from more recent original
documents partially preserved in the archives of the town, the destruc-
tions occurred in the years 1703 and 1736, on tho 9th December,
1742, 30th November, 1744, 22nd February, 1757, 10th February,
1766, and 4th April, 1768, — therefore seven times in 65 years! In
the year 1802 I found four-fifths of the town still in ruins in conse-
quence of the great earthquake of Riobamba on the 4th February,
1797.

TRUE VOLCANOES. 348

Cotonaxi : 32 miles from the former, and about half that dis-
tance from the latter. They are reached by a gallery. The
workmen assert that from the horizontal solid layers, of
which a few are surrounded by loamy pumice fragments,
quadrangular blocks of 20 feet, divided by no transverse fis-
sures, might be procured. The pumice-stone, which is partly
white and partly bluish gray, consists of very fine and long
fibres, with a silky lustre. The parallel fibres have some-
times a knotted appearance, and then exhibit a singular
structure. The knots are formed by roundish particles of
finely porous pumice-stone, from 1 — 1^ line in breadth,
around which long fibres curve so as to inclose them.
Brownish black mica in small six-sided tables, white
crystals of oligoclase, and black hornblende are sparingly
scattered in it ; on the other hand, the glassy felspar, which
elsewhere (Camaldoli, near Naples) occurs in pumice-stone,
is entirely wanting. The pumice-stone of Cotopaxi is very
different from that of the quarries of Zumbalica33 : its fibres
are short, not parallel, but curved in a confused man-
ner. Magnesia-mica, however, is not peculiar to pumice-
stone, for it is also found in the fundamental mass of the
trachyte34 of Cotopaxi. At the more southern volcano,
Tungurahua, pumice-stone appears to be entirely wanting.
There is no trace of obsidian in the vicinity of the quar-

33 This difference has also been recognized by the acute Abich,
(Ueber Natur und Zusammenhang vulkanischer B'ddunyen, 1841,
s. 83).

34 The rock of Cotopaxi has essentially the same mineralogical com-
position, as that of the nearest volcanoes, Antisana and Tuugurahua.
It is a trachyte, composed of oligoclase and augite, and consequently
a Chimborazo-rock : a proof of the identity of the same kind of volcanic
mountain in masses in the opposite Cordilleras. In the specimens col-
lected by me in 1802, and by Boussingault in 1831, the fundamental
mass is partly light or greenish gray, with a pitchstone-like lustre and
translucent at the edges ; partly black, nearly resembling basalt, with
large and small pores, which possess shining walls. The inclosed oligo-
clase is distinctly limited ; sometimes in very brilliant crystals, very dis-
tinctly striated on the cleavage planes; sometimes in small fragments
and difficult of detection. The intermixed augites are brownish and
blackish green and of very variable size. Dark laminae of mica and
black metallic grains of magnetic iron are rarely and probably quite
accidentally sprinkled through the mass. In the pores of a mass con-
taining much oligoclase, there was some native sulphur, probably
deposited by the all- penetrating sulphurous vapours.

344 COSMOS.

ries of Zumbalica, but I have found black obsidian with a
conchoidal fracture in very large masses, immersed in bluish
gray weathered perlite, amongst the blocks thrown out
from Cotopaxi and lying near Mulalo. Of this, fragments
are preserved in the Royal Collection of Minerals at Berlin.
The pumice-stone quarries here described, at a distance of
sixteen miles from the foot of Cotopaxi, appear therefore,
to judge from their mineralogical nature, to be quite fo-
reign to that mountain, and only to stand in the same
relation to it, which all the volcanoes of Pasto and Quito,
occupying many thousand square miles, present to the vol-
canic focus of the equatorial Cordilleras. Have these
pumice-stones been the centre and interior of a proper
crater of elevation, the external wall of which has been
destroyed in the numerous convulsions which the surface
of the earth has here undergone ? or have they been depo-
sited here upon fissures in apparent rest, during the most
ancient foldings of the earth's crust ? For the assump-
tion of aqueous sedimentary alluvia, such as are often exhi-
bited in volcanic tufaceous masses mixed with remains of
plants and shells, is attended with still greater difficul-
ties.

The same questions are suggested by the great mass of
pumice-stone, at a distance from all intuniescent volcanic
platforms, which I found on the Rio Mayo in the Cordil-
lera of Pasto, between Mamendoy and the Cerro del Pul-
pito, 36 miles from the active volcano of Pasto. Leopold
von Buch has also called attention to a similar perfectly
isolated eruption of pumice-stone described by Meyen, which,
consisting of boulders, forms a hill of 320 feet in height,
near the village of Tollo, to the east of Valparaiso, in Chili.
The volcano Maypo, which upheaves Jurassic strata in its
rise, is two full days' journey from this eruption of pumice-
stone **. The Prussian Ambassador in Washington, Fried-
rich von Gerolt, to whom we are indebted for the first

35 "The volcano of Maypo (S. lat. 34° 150 which has never ejected
pumice-stone, is at a distance of two days' journey from the ridge of
Tollo, which is 320 feet in height and entirely composed of pumice-
stone, inclosing vitreous felspar, brown crystals of mica, and small
fragments of obsidian. It is, therefore, an (independent) isolated erup-
tion, quite at the foot of the Andes and close to the plain." Leop. de
Buch, Desc. Phys. des lies Canaries, 1836, p. 470.

TRUE VOLCANOES. 345

coloured geognostic map of Mexico, also mentions "a subter-
ranean quarry of pumice-stone at Bauten," near Huichapa,
32 miles to the south-east of Queretaro, at a distance from
all volcanoes36. The geological explorer of the Caucasus,
Abich, is inclined to believe from his own observations,
that the vast eruption of pumice-stone near the village
Tschegem, in the little Kabarda, on the northern declivity of
the central chain of the Elburuz, is, as an effect of fissure,
much older than the elevation of the very distant conical
mountain just menioned.

If, therefore, the volcanic activity of the earth, by radia-
tion of heat into space during the diminution of its original
temperature, and in the contraction of the superior cooling
strata, produces fissures and wrinkles (fractures et rides),
and therefore simultaneous sinking of the upper and up-
heaval of the lower parts37, we must naturally regard, as
the measure and evidence of this activity in the various
regions of the earth, the number of recognizable volcanic,
platforms (open, conical, and dome-shaped mountains) up-
heaved upon fissures. This enumeration has been repeat-
edly and often very imperfectly attempted : eruptive hills

36 Federico de Gerolt, Cartas Geognosticas de los Principaks Distritos
Mineralcs de Mexico, 1827, p. 5.

37 On the solidification and formation of the crusts of the earth, see
Cosmos, vol. i, pp. 164 — 166. The experiments of Bischof, Charles
Deville, and Delesse have thrown a new light upon the folding of the
body of the earth. See also the older, ingenious considerations of
Babbage, on the occasion of his thermit; explanation of the problem
presented by the temple of Serapis to the north of Puzzuoli, in the
Quarterly Journal of the Geological Society of London, voL iii, 1847,
p. 186 ; Charles Deville, Sur la Diminution de Densite dans les Roches
en passant de I'etat cristallin a I'etat vitreux, in the Comptes rendus
de VAcad. des Sciences, t. xx, 1845, p. 1453; Delesse, Sur les Effets de la
fusion, t. xxv, 1847, p. 455; Louis Frapolli Sur la Caractere Geologique,
in the Bull de la Soc. Geol. de France, 2me se>ie, t. iv, 1847, p. 627; and
above all, Elie de Beaumont, in his important work, Notice sur les
Systemes de Montagnes, 1852, t. iii. The following three sections
deserve the particular attention of geologists : Considerations sur les
Soulevements diis a une diminution lente et progressive du volume de la
Terre, p. 1330 ; Sur 1'Ecrasement Transversal nomme refoulement par
Saussure, comme une des causes dc V elevation des Chalnes de Montagnes,
pp. 1317, 1333, and 1346; Sur la Contraction que les Roches fondues
cprouvent en cristallisant, tendant des le commencement du rejroidisse-
ment du Globe a rendre sa masse interne plus petite que la capadte dt
ton enveloppe exterieure, p. 1235.

346 COSMOS.

and solfataras, belonging to one and the same system, have
been referred to as distinct volcanoes. The magnitude
of the space in the interior of continents which has
hitherto remained closed to all scientific investigation, has
not been so great an obstacle to the solidity of this work as
is commonly supposed, as islands and regions near the coast
are generally the principal seat of volcanoes. In a numerical
investigation, which cannot be brought to a -full conclusion
in the present state of our knowledge, much is already
gained when we attain to a result which is to be regarded
as a lower limit, and when we can determine with great
probability upon how many points the fluid interior of our
earth has remained in active communication with the atmo-
sphere within the historical period. Such an activity
usually manifests itself simultaneously in eruptions from
volcanic platforms (conical mountains), in the increasing heat
and inflammability of thermal springs and naphtha wells,
and in the increased extent of circles of commotion, phe-
nomena which all stand in intimate connection and in mu-
tual dependence38. Here again, also, Leopold von Buch has
the great merit of having (in the supplements to the Phy-
sical Description of the Canary Islands] for the first time
undertaken to bring the volcanic system of the whole earth,
after the fundamental distinction of Central and Linear Vol-
canoes, under one cosmical point of view. My own more
recent, and, probably for this reason, more complete enumera-
tion, undertaken in accordance with principles which I have
already indicated (pp. 245 and 271) and therefore excluding
unopened bell-shaped mountains and mere eruptive cones,
gives, as the probable lower numerical limit (noinbre limite
inferieur), a result which differs considerably from all pre-

33 " The hot springs of Saragyn at the height of fully 5600 feet are re-
markable for the part played by the carbonic acid gas which traverses
them at the period of earthquakes. At this epoch, the gas, like the car-
bonated hydrogen of the peninsula of Apscheron, increases in volume
and becomes heated, before and during the earthquakes in the plain of
Ardebil. In the peninsula of Apscheron, the temperature rises 36°,
until spontaneous inflammation occurs at the moment when and the
spot where an igneous eruption takes place, which is always prognosti-
cated by earthquakes in the provinces of Chemakhi and Apscheron."
Abich, in the Melanges Physiques et Chimiques, t. ii, 1855, pp. 364 — 36a
(see Cosmos, vol. v, p. 175).

TRUE VOLCANOES. 347

vious ones. It is an attempt to indicate the volcanoes
which have been active within the historical period.

The question has been repeatedly raised whether in those
parts of the earth's surface, in which the greatest number
of volcanoes are crowded together, and the reaction of the
interior of the earth upon the hard (solid) crust manifests
the most activity, the fused part may not lie nearer to
the surface ? Whatever be the course adopted to determine
the average thickness of the solid crust of the earth in its
maximum : whether it be the purely mathematical' one
which is presented by theoretical astronomy39, or the simpler
course, founded upon the law of the increase of heat with
depth and the temperature of fusion of rocks40, still the
.solution of this problem presents a great number of values
which are at present undetermined. Amongst these we

39 W. Hopkins, Researches on Physical Geology in the Phil. Transact,
for 1839, pt. ii, p, 311, for 1840, pt. i, p. 193, and for 1842, pt. i, p. 43 ;
also with regard to the necessary relations of stability of the external
surface; Theory of Volcanoes in the British Association Report for 1847,
pp. 45—49.

40 Cosmos, vol. v. pp. 35 — 37 ; Naumann, Geogncsie, Bd. i, pp. 66 — 76 ;
Bischof, Wdrmelehre, s. 382 ; Lyell, Principles of Geology, 1853, pp. 536
— 547 and 562. In the very interesting and instructive work, Sou-
renirs dun Naturaliste, by A. de Quatrefages, 1854, t. ii, p. 469, the
upper limit of the fused liquid strata, is brought up to the small depth
of 20 kilometres : " as most of the silicates fuse at 1231°." " This low
estimate," as Gustav Rose observes, " is founded in an error. The
temperature of 2372°, which is given by Mitscherlich as the melting
point of granite (Cosmos, vol. i, p. 26) is certainly the minimum that we
can admit. I have repeatedly had granite placed in the hottest parts of
a porcelain furnace, and it was always but imperfectly fused. The
mica alone fuses with the felspar to form a vesicular glass ; the quartz
becomes opaque, but does not fuse. This is the case with all rocks
which contain quartz ; and this means may even be made use of for
the detection of quartz in rocks, in which its quantity is so small that
it cannot be discovered with the naked eye, — for example in the
syenite of Plauen, and in the diorite, which we brought in 1829 from
Alapajewsk in the Ural. All rocks which contain no quartz, or any
other minerals so rich in silica as granite, such as basalt for example,
fuse more readily than granite to form a perfect glass in the porcelain
furnace ; but not over the spirit lamp with a double current, which is
nevertheless certainly capable of producing a temperature of 1231°."
In Bischof s remarkable experiments, on the fusion of a globule of
basalt, even this mineral appeared, from some hypothetical assumptions
to require a temperature 264° higher than the melting point of copper.
(Wdrmelekre des Jnnern unsers Erdkbrpcrs, s. 473).

348 COSMOS.

have to mention : the influence of an enormous pressure
upon fusibility, — the different conduction of heat by hetero-
geneous rocks, — the remarkable enfeebling of conductibility
with a great increase of temperature, treated of by Edward
Forbes, — the unequal depth of the oceanic basin, — and the
local accidents in the connection and nature of the fissures,
which lead down to the fluid interior ! If the greater vici-
nity of the upper limit of the fluid interior in particular
regions of the earth may explain the frequency of volcanoes
and the greater multiplicity of communication between the
depths and the atmosphere, this vicinity again may depend
either upon the relative average differences of elevation of
the sea-bottom and the continents, or upon the unequal
perpendicular depth at which the surface of the molten fluid
mass occurs, in various geographical longitudes and latitudes.
But where does such a surface commence ? Are there not
intermediate degrees between perfect solidity and perfect
mobility of the parts ? — states of transition which have
frequently been referred to in the discussions relative to
the plasticity of some Plutonic and volcanic rocks which
have been elevated to the surface, and also with regard to
the movement of glaciers. Such intermediate states abstract
themselves from mathematical considerations, just as much
as the condition of the so-called fluid interior under an
enormous pressure. If it be not even very probable that
the temperature everywhere continues to increase with the
depth in arithmetical progression, local intermediate dis-
turbances may also occur, for example, by subterranean
basins (cavities in the hard mass), which are from time to
time partially-filled from below with fluid lava and vapours
resting upon it41. Even the immortal author of the Pro-
togcea allows these cavities to play a part in the theory of
the diminishing ceotral heat : — " Postremo credibile est con-
trahentem se refrigeratione crustam bullas reliquisse, ingentes
pro rei magnitudine id est sub vastis fornicibus cavitates"1*

41 Cosmos, vol. v, p. 168. See also with regard to the unequal dis-
tribution of the icy soil, and the depth at which it commences, inde-
pendently of geographical latitude, the remarkable observations of
Captain Franklin, Errimn, Kupffer, and especially of Middendorff (loc,
eit. sup, s. 42, 47 and 167).

42 Leibnitz in the Protugcea, § 4.

TRUE VOLCANOES. 349

The more improbable it is that the thickness of the crust
already solidified is the same in all regions, the more impor-
tant is the consideration of the number and geographical
position of the volcanoes which have been open in his-
torical periods. Such an examination of the geography of
volcanoes can only be perfected by frequently renewed
attempts.

I. EUROPE.

Etna,

Volcano in the Liparis,

Sfromboh,

Iscliia,

Vesuvius,

Santorin,

Lemnos,

All belong to the great basin of the Mediterranean, but
to its European and not to its African shores ; and all these
seven volcanoes are still or have been active in known histo-
rical periods ; the burning mountain Mosychlos in Leninos,
which Homer names the favourite seat of Hephaestos was
only destroyed and sunk beneath the wraves of the sea by
earthquakes, together with the island of Chryse, after the time
of the great Macedonian (Cosmos, vol. i, p. 246; Ukert, Geogr.
der Griechen und Rdmer, Th. ii, Abth. 1, s. 198). The
great upheaval of the three Kaimenes in the middle of
the Gulf of Santorin (partly inclosed by Thera, Therasia,
and Aspronisi) which has been repeated several times within
about 1900 years (from 186 B.C. to 1712 of our epoch) had in
their production and disappearance a remarkable similarity
with the relatively unimportant phenomenon of the tem-
porary formation of the islands which were called Graham,
Julia, and Ferdinandea, between Sciacca and Pantellaria.
Upon the peninsula of Methana, which has already been
frequently mentioned (Cosmos, vol. i, p. 239 ; vol. v, p. 229),
there are distinct traces of volcanic eruptions in the reddish
brown trachyte which rises from the limestone near Kai
menochari and Kaimeno (Curtius, Pelop. Bd.ii. s. 439).
Of prehistoric Volcanoes with frcFh traces of the emissioD

350 COSMOS.

of lava, from craters there are, counting from north to south,
those of the Eifel (Mosenberg, Geroldstein) furthest to the
north ; the great crater of elevation in which Schemnitz is
situated; Auvergne (Ghame des Puys or of the Monts
Domes, le Gone du Cantal, les Monts-Dore} ; Vivarais, in
which the ancient lavas have broken out from gneiss (Coupe
d'yAsac, and the cone of Montpezat) ; Yelay : eruptions of
scorise from which no lavas issue ; the Euganean hills ; the
Alban mountains, Rocca Monfina and Vultur, near Teano and
Melfi ; the extinct volcanoes about Olot and Castell Follit
in Catalonia j43 the island group, las Columbretes, near the
coast of Valencia (the sickle-shaped larger island Colum-
braria of the Romans, upon which Montcolibre, latitude
39°54' according to Captain Smyth, is full of obsidian and
cellular trachyte); the Greek island "Nisyros, one of the
Carpathian Sporades, of a perfectly round form, in the
middle of which, at an elevation of 2270 feet according to
Ross, there is a deep, walled cauldron with a strongly deto-
nating solfatara, from which at one time radiating lava-
streams poured themselves into the sea, where they now
form small promontories, and furnished volcanic millstones
in Strabo's time (Ross, JReisen auf den qriecliischen Inseln,
Bd. ii, s. 69 and 72—78). For the British islands we
have here still to mention, on account of the antiquity of
the formations, the remarkable effects of submarine vol-
canoes upon the strata of the lower Silurian formation
(Llandeilo strata) cellular volcanic fragments being baked
into these strata, whilst, according to Sir Roderick Murchi-
son's important observation, even eruptive trapp-masses pene-
trate into lower Silurian strata in the Corndon mountains
(Shropshire and Montgomeryshire) ;** the dyke-phenomena
of the isle of Arran ; and the other points in which the in-
terference of volcanic activity is visible, although no traces
of true platforms are to be discovered.

43 With regard to Vivarais and Velay, see the very recent and accu-
rate researches of Girard in his GeologiscJien Wandcrungen, Bd. i,
(1856) s. 161, 173 and 214. The ancient volcanoes of Olot were
discovered by the American geologist Maclure in 1808, visited by Lyell
in 1830, and well described and figured by the latter in his Manual of
Geology 1855, pp. 535 — 542.

41 Sir Roderick Murchison, Siluria, pp. 20 and 55—58 (Lyell,
Manual, p. 563).

TKUE VOLCANOES.

II. ISLANDS OP THE ATLANTIC OCEAN.

The volcano Esk, upon the island of Jan Mayen, ascended
by the meritorious Scoresby and named after his ship;
height scarcely 1600 feet. An open, not ignited summit-
crater ; basalt, rich in pyroxene and trass.

South-west of the Esk, near the North Cape of Egg Island,
another volcano, which, in April 1818, presented high erup-
tions of ashes every four months.

The Beerenberg, 6874 feet in height, in the broad, north-
eastern part of Jan Mayen (lat. 71° 4") is not known to be a
volcano.46

Volcanoes of Iceland : Oerafa, Hecla, Rauda-Kamba . . .

Volcano of the island of Pico46 in the Azores : a great
eruption of lava from the 1st May to the 5th June, 1800.

The Peak of Teneriffe.

Volcano of Fogo,41 ono of the Cape de Verde Islands.

Prehistoric volcanic activity. — This on Iceland is less defi-
nitely attached to certain centres. If we divide the volcanoes
of the island, with Sartorius von Waltershausen, into two
classes, of which those of the one have only had a single
eruption, whilst those of the other repeatedly emit lava-
streams at the same principal fissure, we must refer to the
former, ftauda-Kamba, Scaptar, Ellidavatan, to the south-
east of Reykjavik . . . . ; to the second, which exhibits a
permanent individuality, the two highest volcanoes of Ice-
land Oerafa (more than 6390 feet) and Snaefiall, Hecla, <fcc.
Snaefiall has not been in activity within the memory of man,
whilst Oerafa is known by the fearful eruptions of 1362 and
1727 (Sart. von Waltershausen, Skizze von Island, a. 108

45 Scoresby, Account of the Arctic Regions, vol. i, pp. 155 — 169, tab.
v and vi.

46 Leop. von Buch, Descr. des lies Canaries, pp. 357 — 369, and Land-
grebe, Naturgcschichte der Vulkane, 1855, Bd. i, s. 121 — 136 : and with
regard to the circumvallations of the craters of elevation (Caldeiras)
upon the Islands of Saint Michael, Fayal and Terceira (from the maps
of Captain Vidal) (see page 226). The eruptions of Fayal (1672) and
Saint George (1580 and 1808) appear to be dependent upon the prin-
cipal volcano, the Pico.

* See pages 248 and 262.

352 COSMOS.

and 112). In Madeira,48 the two highest mountains, the
conical Pico Huivo, 6060 feet in height, and the Pico de
Torres, which is but little known, covered on their steep
declivities with scoriaceous lavas, cannot be regarded as the
central point of the former volcanic activity on the whole
island, as in many parts of the latter, especially towards the
coasts, eruptive-orifices and even a large crater, that of the
Lagoa, near Machico, are met with. The lavas, thickened
by confluence, cannot be traced far as separate streams.
Remains of ancient Dicotyledonous and .Fern -like vegeta-
tion, carefully investigated by Charles Bunbury, are found
buried in upheaved strata of volcanic tufa and loam, some-
times covered by more recent basalt. Fernando de Noronha,
lat. 3° 50' S. and 2° 27' to the east of Pernambuco : a group
of very small islands ; phonolitic rocks containing horn-
blende,— no crater, but vein-fissures filled with trachyte
and basaltic amygdaloid, penetrating white tufa layers.49
The island of Ascension ; highest summit 2868 feet ; basal-
tic lavas with more glassy felspar than olivine sprinkled
through them, and well bounded streams traceable up to the
eruptive cone of trachyte. The latter rock of light colours,
often broken up like tufa, predominates in the interior and
south-east of the island. The masses of scoriae thrown out
from Green Mountain, inclose immersed angular fragments60
containing syenite and granite, which remind one of the
lavas of Jorullo. To the westward of Green Mountain,
there is a large open crater. Volcanic bombs, partly hollow,
of as much as 10 inches in diameter lie scattered about in
innumerable quantities, together with large masses of obsi-
dian. Saint Helena : the whole island volcanic, the beds ol
lava in the interior rather felspathic ; basaltic towards the
coast, penetrated by innumerable dykes as at Flagstaff Hill.
Between Diana Peak and JS"estlodge, in the central series of
mountains, is the curved and crescentic shaped fragments
of a wider, destroyed crater full of scoriae and cellular lava

48 Results of the observations upon Madeira by Sir Charles Lyell and
Hartung in the Manual of Geology 1855, pp. 515 — 525.

49 Darwin, Volcanic Islands 1844, p. 23, and Lieutenant Lee, Cruise
of the U.S. Brig Dolphin, 1 854, p. 80.

50 See the admirable description of Ascension in Darwin's Volcanic
Islands, pp. 40 and 41.

TRUE VOLCANOES. 353

"the mere wreck51 of one great crater is left "). The beds of
lava are not limited and consequently cannot be traced as true
streams of small breadth. Tristan da Cuiiha (kt. 37° 3' S.,
long. 11°26'W.) discovered as early as 1506 by the Portuguese -,
a small circular island of six miles in diameter, in the
centre of which a conical mountain is situated, described by
Captain Denham as about 8300 feet in height and composed
of volcanic rock (Dr. Petermann's Geogr. Mittheil. 1855,
No. iii, s. 84). To the south-east, but' in 53° S. latitude,
lies the equally volcanic Thompson's Island and between
the two in the same direction, Gough Island, &lso called
Diego Alvarez. Deception Island, a slender, narrowly
opened ring (S. lat. 62° 55'), and Bridgeman's Island belong-
ing to the South Shetlands group ; both volcanic, with layers
of ice, pumice-stone, black ashes and obsidian ; perpetual
eruption of hot vapours (Kendal, Journal of the Geographical
Society, vol. i, 1831, p. 62). In February, 1842, Deception
Island was seen to produce flames simultaneously at 13
points in the ring (Dana in United States Explor. Exped.
vol. x, p. 548). It is remarkable that, as so many islands in
the Atlantic Ocean are volcanic, neither the entire flat islet
of Saint Paul52 (Penedo de S. Pedro), one decree to the north
of the equator ; nor the Falklands (with thin quartzose
clay-slate), South Georgia or Sandwich land, appear to offer
any volcanic rock. On the other hand a region of the
Atlantic Ocean, about 0° 20' to the south of the equator,
longitude 22° W., is regarded as the seat of a submarine
volcano.53 In this vicinity Krusenstern saw black columns
of smoke rise out of the sea (19th May 1806), and in 1836
volcanic ashes collected at the same point (south-east from
the above mentioned rock of Saint Paul) on two occasions,

51 Darwin, pp. 84 and 92, with regard to " the great hollow space or
valley southward of the central curved ridge, across which the half of
the crater must once have extended. It is interesting to trace the steps,
by which the structure of a volcanic district becomes obscured and
finally obliterated" (See also Scale, Geognosy of the Island of Sain
Helena, p. 28).

52 St. Paul's Rocks. (See Darwin, pp. 31—33 and 125).

53 Daussy on the probable existence of a submarine volcano in the
Atlantic, in the Comptes rendus de I' A cad. des Sciences, t. vi, 1858,
p. 512 ; Darwin, Volcanic Islands, p. 92 ; Lee, Cruise of the U.S. Brig
Dolphin, pp. 2—55 and 61.

VOL. V. 2 A

354: COSMOS.

were exhibited to the Asiatic Society of Calcutta. According
to very accurate investigations by Daussy, singular shocks
and agitation of the sea, ascribed to the commotion of the
sea-bottoin by earthquakes, have been observed in this vol-
canic region, as it is called in the new and beautiful American
chart of Lieutenant Samuel Lee (Track of the Surveying Brig
Dolphin, 1854), five times between 1747 and Krusenstern's
circumnavigation of the globe and seven times from 1806 to
1836. But during the recent expedition of the brig Dol-
phin (January 1852), as previously (1838), during Wilkes's
exploring expedition, nothing remarkable was observed,
although the brig was ordered " on account of Krusenstern's
volcano " to make investigations with the lead between the
equator and 7° S. latitude, and about 18° to 27° longitude.

III. AFRICA.

It is stated by Captain Allan that the volcano Mongo-ma
Leba in the Cameroon Mountains (4° 12' N. lat.), westward
of the mouth of the river of the same name in the Bight of
Biafra, and eastward of the Delta of the Kowara, or Niger,
emitted an eruption of lava in the year 1838. The four
high volcanic islands of Annabon, St. Thomas, Isla do
Principe, and San Fernando Po, which run on a fissure
in a direct linear series from SS.W. to NN.E., point to the
Cameroons, which, according to the measurements of Captain
Owen and Lieutenant Boteler, rises to the great altitude of
nearly 13,000 feet.64

A volcano (?) a little to the west of the Snowy Mountain
Kignea in Eastern Africa, about 1°20' S. lat. was discovered
by the missionary Krapf in 1849, near the source of the
River Dana, about 320 geographical miles north-west of the
coast of Mombas. In a parallel nearly two degrees more
southerly than the Kignea is situated another snowy moun-
tain, the Kilimandjaro, which was discovered by the mis-
sionary Rebmann in 1847, perhaps scarcely 200 geographical
miles from the same coast. A little to the westward lies a
third snowy mountain, the Doengo Engai, seen by Captain

54 Gumprecht, Die vulkanische ThatigTceit auf dem Festlande von
Afrtfca, in Arabien und auf den Insdn des rothen Meeres, 1849, s. 18.

TRUE VOLCANOES. 355

Short. The knowledge of the existence of these mountains
is the result of laborious and hazardous researches.

Evidences of pre-historical volcanic action in the great
continent, the interior of which between the seventh degree
north and the twelfth degree south latitude (the parallels of
Adamaua and the Lubalo Mountain, which acts as a water-
shed,) still remains so unexplored, are furnished, according
to Ruppell, by the country surrounding the Lake Tzana, in
the kingdom of Gondar, as well as by the basaltic lavas,
trachytes, and obsidian strata of Shoa, according to Rochet
d'Hericourt, whose mineralogical specimens, quite analogous
to those of Cantal and Mont Dore, may have been exa-
mined by Dufrenoy (Comptes rendus, t. xxii. pp. 806 — 810).
Though the conical mountain Koldghi in Cordofan is not
now seen either in a burning or smoking state, yet it ap-
pears that the existence of a black, porous, and vitrified rock
has been ascertained there.65

In Adamaua, south of the great Benue river, rise the
isolated mountain-masses of Bagele and Alantika, which
from their conical and dome-like forms appeared to Dr. Earth,
on his journey from Kuka to lola, to resemble trachyte
mountains. According to Petermann's notices from the note-
books of Overweg, (of whose researches natural science was
so early deprived) that traveller found in the district of
Gudsheba, westward of the lake of Tshad, separate basaltic
cones, rich in olivine and columnar in form, which were
sometimes intersected by layers of the red, clayey-sandstone,
and sometimes by those of quartzose granite.

The small number of now ignited volcanoes in the undi-
vided continents, whose coast-lands are sufficiently known,
is a very remarkable phenomenon. Can it be that in the
unknown regions of Central Africa, especially south of the
equator, large basins of water exist, analogous to Lake
TJniames (formerly called by Dr. Cooley, N 'yassi), on whose
shores rise volcanoes, like the Demavend near the Caspian
Sea ? Much as the natives are accustomed to move about
over the country, none of them have hitherto brought us the
least notice of any such thing !

55 Cosmos, vol. 1, p. 244, note J. For the whole of the phenomena
hitherto known in Africa, see Landgrebe, Natwyescltichte der Vulkanc,
Bd. i, B. 195—219.

2 A2

356 COSMOS.

IV. ASIA.

a. The Western and Central part.

The volcano of Demavend,66 in a state of ignition, but,
according to the accounts of Olivier, Morier and Taylor
Thomson (1837), smoking only moderately, and not uninter-
ruptedly.

The volcano of Medina (eruption of lava in 1276).

The volcano of Djebel el Tir (Tair or Tehr), an insular
mountain 895 feet high, between Loheia and Massaua in the
Red Sea.

The volcano of Peshan, northward of Kutsche in the great
mountain-chain of the Thian-schan or Celestial Mountains in
Central Asia ; eruptions of lava within the true historical
period, from the year 89 up to the beginning of the seventh
centuiy of our era.

The volcano of Ho-cheu, called also sometimes in the very
circumstantial Chinese geographies the volcano of Turfan ;
120 geographical miles from the great Solfatara of Urumtsi,
near the eastern extremity of the Thian-schan, in the direc-
tion of the beautiful fruit country of Hami.

The volcano of Demavend, which rises to a height of up-

56 The height of Demavend above the sea was given by Ainsworth
at 14,695, but after correcting a barometrical result, probably attri-
butable to an error of the pen (Asie Centrale, t. iii, p. 327), it amounts,
according to Ottman's tables to fully 18,633 feet. A somewhat greater
elevation, 20,085 feet, is given by the angles of altitude worked by my
friend, Captain Lemm, of the Russian navy, in the year 1839, and
which are certainly very correct, but the distance is not trigonome-
trically laid down, and rests on the presumption that the volcano
of Demavend is 66 versts distant from Teheran (one equatorial
degree being equal to 104^y versts). Hence it would appear that the
Persian volcano of Demavend, covered with perpetual snow, situated so
near the southern shore of the Caspian Sea, but distant 600 geogra-
phical miles from the Colchian coast of the Black Sea, is higher than
the great Ararat by about 2989 feet and the Caucasian Elburuz by
probably 1600 feet. On the Demavend, see Hitter, Erdkunde von
Asien, Bd. vi, Abth. i, s. 551 — 571, and on the connection of the name
Albordj, taken from the mythic and therefore vague geography of the
Zend-nation, with the modern name Elburz (Koh Alburz of Kazwini)
and Elburuz, see ibid. s. 43—49, 424, 552, and 555.

TRUE VOLCANOES. 357

wards of 19,000 feet, lies nearly 36 geographical miles from
the southern shore of the Caspian Sea, in Mazeuderan, and
almost at the same distance from Resht and Asterabad, on
the chain of the Hindu-kho which slopes suddenly down
to the west in the direction of Herat and Mesh id. I have
elsewhere (Asie Centrale, t. i, pp 124 — 129 ; t. iii, pp. 433—
435) mentioned the probability that the Hindu-kho of
Chitral and Kafiristan is a westerly continuation of the
mighty Kuen-lim, which bounds Tibet towards the north
and intersects the Bolor Mountains in the Tsungling. The
Demavend belongs to the Persian or Caspian Elburz, a sys-
tem of mountains which must not be confounded with the
Caucasian ridge of the same name (now called Elburuz), and
which lies 7£° further north and 10° further west. The
word Elburz is a corruption of Alborj, or Mountain of the
World, which is connected with the ancient cosmogony of
the Zends.

While the volcano of Demavend, according to the gene-
rality of geognostic views on the direction of the mountain-
chains of Central Asia, bounds the great Kuen-lun chain
near its western extremity, another igneous appearance at
its eastern extremity, the existence of which I was the first
to announce (Asie Centrale, t. ii, pp. 427 and 483), deserves
particular notice. In the course of the important researches
which T recommended to my respected friend and colleague
in the Institute, Stanislas Julien, with the view of deriving
information from the rich geographical sources of old Chinese
literature on the subject of the Bolor, the Kuen-lun, and the
Sea of Stars, that intelligent investigator discovered in the
great Dictionary published in the beginning of the eighteenth
century by the Emperor Yong-ching a description of the
" eternal flame " which issues from an opening in the hill
called Shin-khien, on the eastern slope of the Kuen-lun.
This luminous phenomenon, however deeply seated it may
be, cannot well be termed a volcano. It appears to me
rather to present an analogy with the Chimaera in Lycia,
near Deliktash and Yanartash, which was so early known
to the Greeks. This is a stream of fire, an issue of gas con-
stantly kindled by volcanic action in the interior of the
earth (See page 256, note 50).

Arabian writers inform us, though lor the most part

358 COSMOS.

without quoting any precise year, that lava-ei uptions have
taken place during the middle ages on the south-western
shore of Arabia, in the insular chain of the Zobayr, in the
Straits of Bab-el-Mandeb and Aden (Wellsted, Travels in
Arabia, vol. ii, pp. 466 — 468), in Hadhramaut, in the Strait
of Ormuz, and at different points in the western portion of
the Persian Gulf. These eruptions have always occurred on
a soil which had already been in pre-historical times the seat
of volcanic action. The date of the eruption of a volcano at
Medina itself, 12|° northward of the Straits of Bab-el-
Mandeb, was found by Burckhardt in Samhudy's Chronicle
of the famous city of that name in the Hedjaz. It took
place on the 2nd November, 1276. According to Seetzen,
however, Abulmahasen states that an igneous eruption had
occurred there in 1254, which is twenty-two years earlier
(see Cosmos, vol. i, p. 246). The volcanic island of Djebel-
tair, in which Vincent recognized the " burnt-out island " of
the Periplus Maria lErytJircei, is still active and emits smoke,
according to Botta and the accounts collected by Ehrenberg
and Russegger (Jteisen in Europa, Asien und Africa, Bd. ii,
Th, 1, 1843, s. 54). For information respecting the entire
district of the Straits of Bab-el-Mandeb, with the basaltic
island of Perini, — the crater-like circumvallation, within
which lies the town of Aden, — the island of Seerah with
streams of obsidian, covered with pumice, — the island-
groupes of the Zobayr and the Farsan (the volcanic nature
of the latter was discovered by Ehrenberg in 1825) I refer
my readers to the interesting researches of Ritter in his
Erdkunde von Asien, Bd. viii, Abth. 1, s. 664—707, 889—
891, and 1021—1034.

The volcanic mountain-chain of the Thian-schan (Asie
Centrale, t. i, pp. 201 — 203 ; t. ii, pp. 7 — 51), a range which
intersects Central Asia between Altai and Kuen-lun from
east to west, formed at one period the particular object of
my investigations, so that I have been enabled to add to the
few notices obtained by Abel-Remusat from the Japanese
Encyclopaedia, some fragments of greater importance dis-
covered by Klaproth, Neumann, and Stanislas Julien (Asie
Centrale, t. ii, pp. 39—50 and 335—364). The length of
the Thian-schan is eight times greater than that of the
Pyrenees, if we include the Asferah which is on the other

TKUE VOLCANOES. 359

side of the intersected meridian-chain of the Kusyurt-Bolor,
stretching westward as far as the meridian of Samarcand,
and in which Ibn Haukal and Ibn-al-Vardi describe streams
of fire, and notice luminous (?) fissures emitting sal am-
moniac (see the account of Mount Botom, ut supra). In
the history of the dynasty of Thang it is expressly stated
that on one of the slopes of the Pe-shan, which continually
emits fire and smoke, the rocks burn, melt and flow to the
distance of several li, like a " stream of melted fat. The
soft mass hardens as it cools." It is impossible to describe
more characteristically the appearance of a stream of lava.
Moreover, in the forty-ninth book of the great geography of
the Chinese empire, which was printed at Pekin from 1789
to 1804 at the expense of the state, the burning mountains
of the Thian-schan are described as " still active." Their
position is very central, being nearly equi-distant (1520 geo-
graphical miles) from the nearest shore of the Frozen Ocean
and from the mouth of the Indus and Ganges, 1020 miles
from the Sea of Aral, 172 and 208 miles from the salt-lakes
of Issikal and Balkasch. Information respecting the flames
issuing from the mountain of Turfan (Hotscheu) has also
been furnished by the pilgrims of Mecca, who were ofiicially
examined at Bombay in the year 1835 (Journal of the Asiatic
Soc. of Bengal, vol. iv, 1835", pp. 657—664). When may we
hope to see the volcanoes of Peschan and Turfan, Barkul and
Hami explored by some scientific traveller, by way of
Gouldja on the Ili, which may be easily reached.

The better knowledge now possessed of the position of the
volcanic mountain chain of the Thian-schan has very naturally
given rise to the question whether the fabulous territory of
Gog and Magog where " eternal fire " is said to burn at the
bottom of the River El Macher, is not in some way con-
nected with the eruptions of the Peschan or the volcano of
Turfan. This oriental myth, which had its origin westward
of the Caspian Sea, in the Pylis Albanian near Derbend, has
travelled, like all other myths, far towards the East. Edrisi
gives an account of the journeying of one Salam el Terdje-
man. the dragoman of one of the Abbasside-Chalifs, in the
first half of the ninth century, from Bagdad to the Land of
Darkness. He proceeded through the steppe of Baschkir to
the snowy-mountain of Cocaia, which is surrounded by the

360 COSMOS.

great wall of Magog (Madjoudj). Ame"de"e Jaubert, to whom
we are indebted for important supplements to the Nubian
geographers, has shown that the fires which burn on the
slope of the Coca'ia have nothing volcanic in their nature
(Asie Centrale, t. ii, p. 99). Edrisi places the Lake of Te-
hama further to the south. I think I have said enough to
show the probability of the Tehama being identical with the
great Lake of Balkasch, into which the Hi flows, and which
is only 180 miles further south. A century and a half later
than Edrisi, Marco Polo placed the wall of Magog among
the mountains of In-schan, to the east of the elevated plain of
Gobi, in the direction of the River Hoang-ho and the Chinese
wall, respecting which, singularly enough, the famous Vene-
tian traveller is as silent as he is on the subject of the use of
tea. The In-shan, the limit of the territory of Prester John,
may be regarded as the eastern prolongation of the Thian-
schan (Asie Centrale, t. ii, pp. 92—104).

The two conical volcanic mountains, the Petschan and
Hotshen of Turfan, which formerly emitted lava, and which
are separated from each other at a distance of about 420
geographical miles by the gigantic block of mountains called
the Bogdo-Oola, crowned with eternal snow and ice, have
long been erroneously considered an isolated volcanic group.
I think I have shown that the volcanic action north and
south of the long chain of the Thian-schan here, as well as
in the Caucasus, stands in close geognostic connection with
the limits of the circle of terrestrial commotion, the hot-
springs, the solfataras, the sal-ammoniacal fissures and beds
of rock-salt.

According to the view I have already frequently ex-
pressed, and in which the writer most profoundly acquainted
with the Caucasian mountain system (Abich) now coin-
cides, the Caucasus itself is only a continuation of the ridge
of the volcanic Thian-schan and Asferah on the other side
of the great Aralo- Caspian depression.67 This is therefore
the place, in connection with the phenomena of the Thian-
shan, to cite as belonging to pre-historical periods the four
extinct volcanoes of Elburuz, 18,494 feet in height, Ararat
17,112 feet, Kasbegk 16,532 feet, and Savalan 15,760 feet

i7 Asie Centrale, t. ii, pp. 9, and 54—58. See also page 208,
note 61, of the present volume.

TRUE VOLCANOES. 361

hiu'h." In point of height these mountains stand between
Cotopaxi and Mont Blanc. The Great Ararat (Agri-dagh),
ascended for the first time on the 27th September, 1829, by
Friedrich von Parrot, several times during 1844 and 1845
by Abich, and lastly in 1850 by Colonel Cbodzko, is dome-
shaped, like Chimborazo, with two extremely small eleva-
tions on the border of the summit, but without any crater
at the apex. The most extensive and probably the latest
pre-historical lava-eruptions of Ararat have all issued below
the limit of perpetual snow. The nature of these eruptions
is two-fold ; they are sometimes trachytic with glassy feld-
spar, interspersed with pyrites which readily weather, and
sometimes doleritic, composed of labradorite and augite, like
the lavas of Etna. The doleritic lavas of Ararat are con-
sidered by Abich to be more recent than the trachytic. The
points of emission of the lava-streams, which are all beneath
the limit of perpetual snow, are frequently indicated (as, for
example, in the extensive grassy plain of Kip-ghioll, on the
north-western slope) by eruptive cones and by small craters
encircled by scoriae. Although the deep valley of St. James
which extends to the very summit of Ararat, and gives a
peculiar character to its form, even when seen at a distance,
exhibits much resemblance to the Yal del Bove on Etna, and
displays the internal structure of the Dome, yet there is this
striking difference between them, that in the valley of St.
James massive trachytic rock alone is found, and no streams of
lava, beds of scori* or rapilli.69 The Great and Little Ararat,
the first of which is shown by the geodetic labours of Wasili
Fedorow, to be 3'4" more northerly and 6'42" more westerly
than the other, rise on the southern edge of the great plain

58 Elburuz, Kasbegk, and Ararat, according to communications
from Struve, Asie Centrale, t. ii, p. 57. The height of the extinct
volcano of Savalan, westward of Ardebil, as given in the text is
founded on a measurement of Chanykow. See Abich in the Melanges
Phys. et Chini, t. ii, p. 361. To save tedious repetition in the citation
of the sources on which I have drawn, I would here explain that
everything in the geological section of Cosmos, relating to the impor-
tant Caucasian isthmus, is borrowed from manuscript essays of the
years 1852 and 1855 communicated to me by Abich in the kindest
and friendliest manner for my unrestricted use.

59 Abich, Notice Explicative d'une Vue de £ Ararat, in the Bulletin de
la Soc. de Geographic de France, 4eme s^rie, t. i, p. 516.

362 COSMOS.

through which the Araxes flows in a large bend. They both
stand on an elliptic volcanic plateau, whose major axis runs
south-east and north-west. The Kasbegk and the Tshegem
have likewise no summit crater, although the former has
thrown out vast eruptions towards the north, in the direc-
tion of Wladikaukas. The greatest of all these extinct vol-
canoes, the trachytic cone of the Elburuz, which has risen
out of the talc and dioritic schistous mouutains, rich in
granite, of the valley of the lliver Backsan, has a crater-lake.
Similar crater-lakes occur in the rugged highlands of Kely,
from which streams of lava flow out between eruption-cones.
Moreover, the basalts are here, as well as in the Cordilleras
of Quito, widely separated from the trachyte- system ; they
commence from twenty-four to thirty-two miles south of the
chain of the Elburuz, and of the Tschegem on the Upper
Phasis or Rhion valley.

P . The north-eastern portion (the Peninsula of
KamtscTiatka).

The peninsula of Kamtschatka, from Cape Lopatka,
which, according to Krusenstern is in lat. 51°3', as far north
as to Cape Ukinsk, belongs, in common with the island of
Java, Chili and Central America, to those regions in which
the greatest number of volcanoes, and, it may be added, of
still active volcanoes, are compressed within a very small
area. Fourteen of these are reckoned in Kamtschatka
within a range of 420 geographical miles. In Central Ame-
rica I find in a space of 680 miles, from the volcano of
Coconusco to Turrialva in Costa Rica, twenty-nine volcanoes,
eighteen of which are still burning ; in Peru and Bolivia,
over a space of 420 miles, from the volcano Chacani to
that of San Pedro de Atacama, fourteen volcanoes, of which
only three are at present active, and in Chili, over a space
of 960 miles, from the volcano of Coquimbo to that of San
Clemente, twenty-four volcanoes. Of the latter, thirteen are
known to have been active within the periods of time em-
braced in historical records

Our acquaintance with the Kamtschatkan volcanoes, in
respect to their form, the astronomical determination of their
position and their height, has been vastly extended in recent

TRUE VOLCANOES. 363

times by Krusenstern, Horner, Hofmann, Lenz, Liitke,
Postels, Captain Beechey, and above all by Adolph Erman.
The peninsula is intersected lengthwise by two parallel
mountain chains, in the most easterly of which the volcanoes
are accumulated. The loftiest of these attain a height of
from 11,190 to 15,773 feet. They lie in the following order
from south to north :

The Opalinskian volcano (the Pic Koscheleff of Admiral
Krusenstern) lat. 51° 21'. According to Captain Chwostow,
this mountain rises to the height of the Peak of Tenerifie,
and was extremely active at the close of the 18th century.

The Hodutka Sopka (51° 35'). Between this and the one
just noticed, there lies an unnamed volcanic cone (51° 32'),
which, however, according to Postels, seems, like the Ho-
dutka, to be extinct.

Poworotnaja Sopka (52° 22'), according to Captain
Beechey, 7930 feet high (Erman's Eeise, t. iii, p. 253;
Leop. von Buch, Hes Can. p. 447).

Assatschinskaja Sopka (52° 2') ; great discharges of ashes,
particularly in the year 1828.

The Wiljutschinsker volcano (52° 52') ; according to
Captain Beechey 7373 feet, according to Admiral Liitke
6744 feet high. Distant only 20 geographical miles from
the harbour of Petropolowski on the north side of the Bay
of Torinsk.

Awatschinskaja or Gorelaja Sopka (53° 17'), according to
Erman, 8910 feet high ; first ascended during the expedition
of La Perouse in 1787 by Mongez andBernizet ; afterwards
by my dear friend and Siberian fellow-traveller, Ernst Hof-
mann (in July, 1824, during the circumnavigation of the
globe by Kotzebue ; by Postels and Lenz during the ex-
pedition of Admiral Liitke in 1828, and by Erman in
September 1829. The latter made the important geog-
nostic observation that the uphea\mg trachyte had pierced
through slate and grey-wacke (a silurian rock). The still
smoking volcano had a terrific eruption in October 1837,
there having previously been a slight one in April, 1828
(Postels in Lutke, Voyage, t. Bd. s, 67 — 84 ; Erman, Reise,
Hist. Eericht, Bd. iii, s. 494 and 534—540).

In the immediate neighbourhood of the Awatscha-vol-
cano (see page 248) lies the Koriatikaja or Strjeloschnaja

364 COSMOS.

Sopka (lat. 53° 19'), 11,210 feet high, according to Lutke,
t. iii, p. 84. This mountain is rich in obsidian, which the
Kamtschatkans so late as the last century made into arrow-
heads, as the Mexicans and the ancient Greeks used to do.

Jupanowa Sopka, lat. according to Erman's calculation
(Reise, Bd. iii, s. 469) 53° 32'. The summit is pretty flat,
and the traveller just mentioned expressly states " that this
Sopka, on account of the smoke it emits, and its perceptible
subterranean rumbling, is always compared to the mighty
Schiwelutsch, and reckoned among the undoubted igneous
mountains." Its height, as measured by Liitke from the
sea, is 9055 feet.

Kronotskaja Sopka, 10,609 feet, at the lake of the same
name, lat. 54° 8' ; a smoking crater on the summit of the
very sharp-pointed conical mountain (Liitke, Voyage, t. iii,
p. 85).

The volcano Schiwelutsch, 20 miles south-east of Jelowka,
respecting which we possess an admirable work by Erman
(Reise, Bd. iii, s. 261—317, and Phys. Beob., Bd. i, s. 400
— 403) previous to whose journey the mountain was almost
unknown. Northern peak, lat. 56° 40', height 10,544 feet ;
southern peak, lat. 56° 39', height 8793 feet. When Erman
ascended the Schiwelutsch in September, 1829, he found it
smoking vehemently. Great eruptions took place in 1739,
and between 1790 and 1810; the latter consisting, not of
flowing, melted lava, but of ejections of loose volcanic stones.
C. von Dittmar relates that the northern peak fell in during
the night from the 17th to 18th February 1854. At that
time an eruption which still continues took place, accom-
panied by genuine streams of lava.

Tolbatschinskaja Sopka ; smoking violently, but in earlier
times frequently changing the openings through which it
ejected its ashes. According to Erman, lat. 55° 51' and
height 8313 feet.

TJschinskaja Sopka; closely connected with the Kliuts-
chewsker volcano ; lat. 56° 0', height 11,723 feet (Buch, Can.
p. 452 ; Landgrebe, Volkane, vol. i, p. 375).

Kliutschewskaja Sopka (56° 4') : the highest and most ac-
tive of all the volcanoes of the peninsula of Kamtschatka ;
thoroughly examined by Erman, both geologically and hyp-
sonietrically. According to KraschenikofFs report, the

TRUE VOLCANOES. 365

Kliutschewsk had great igneous eruptions from 1727 to
1731, as also in 1767 and 1795. On the llth of September
1829, Erman performed the hazardous feat of ascending the
volcano, and was an eye-witness of the ejection of red-hot
stones, ashes, and vapour from the summit, while at a great
distance below it an immense stream of lava flowed from
a Assure on the western declivity. Here also the lava is rich
in obsidian. According to Erman (Beob., vol. i, pp. 400 —
403 and 419) the geographical latitude of the volcano is 56D4',
and its height in September 1829 was, on a very accurate
talculation, 15,763 feet. In August 1828; on the other hand,
Admiral Liitke, on taking angles of altitude at sea, at a
distance of 160 knots (40 nautical miles) found the summit
of Kliutschewsk 16,498 feet high (Voyage,*, iii, p. 86;
Landgrebe, Vulkane, Bd. i, s. 375—386). This measure-
ment, and a comparison of the admirable outline drawings.
of Baron von Kittlitz, who accompanied Lutke's expedition
on board the Seniawin, with what Erman himself observed
in September 1829, led the latter to the conclusion that, in
this short period of thirteen months, great changes had taken
place in the form and height of the summit. "I am of
opinion," says Erman (Reise,vol. iii, p. 359), "that we can
scarcely be wrong in assuming the height of the summit in
August 1828, to have been 266 feet more than in September
1829, during my stay in the neighbourhood of Kliutschi,
and that therefore its height at the former of these periods
must have been 16,029 feet." In the case of Vesuvius I
found, by my own calculations (founded on Saussure's
barometrical measurement in 1773), of the Rocca del Palo,
the highest northern margin of the crater, that up to the
year 1805, that is to say, in the course of thirty-two years,
this northern margin of the crater had sunk 35 \ feet, while
from 1773 to 1822, or forty-nine years, it had risen (appa-
rently) 102 feet (Views of Nature, 1850, pp. 376—378). In
the year 1822, Monticelli and Covelli calculated the Rocca
del Palo at 3990 feet, and I at 4022 feet ; I then gave
3996 as the most probable result for that period. In the
spring of 1855, thirty -three years later, the delicate baro-
metrical measurements of the Olmutz astronomer, Julius
Schmidt, again brought out 3990 feet (Neue Bestimm. am
Vesuv. 1856, s. i, 16 and 33). It would be curious to

366 COSMOS.

know how much should here be attributed to imperfec-
tion of measurement and barometrical formula. Investiga-
tions of this kind might be multiplied on a larger scale
and with greater certainty if, instead of often repeated com-
plete trigonometrical operations or, in the case of acces-
sible summits, the more practicable, though less satisfactory
barometrical measurements, operators would confine them-
selves to determining, even to fractions of seconds, at com-
parative periods of twenty-five or fifty years, the simple
angle of altitude of the margin of the summit, from the
same point of observation, and one which could with cer-
tainty be found again. On account of the influence of
terrestrial refraction, I would recommend that, in each of
the normal epochs, the mean result of three days' observa-
tions at different hours should be taken. In order to obtain,
not only the general result of the increase or diminution of
the angle, but also the absolute amount of the change in
feet, the distance would require to be determined previously
only once for all. What a rich source of knowledge relative
to the twenty volcanic Colossi of the Cordilleras of Quito,
would not the angles of altitude, determined for more than a
century by the labours of Bouguer and La Condamine have
provided, had those travellers accurately designated as fixed
and permanent points the stations whence they measured
the angles of altitude of the summits. According to
C. von Dittmar the Kliutschewsk was entirely quiescent
since the eruption of 1841 until the lava burst forth again
in 1853. The falling in, however, of the summit of the
Schiwelutsch interrupted the new action {Bulletin de la
Clause Physico-Mathem. de V Acad. des Sc. de St. Petersbourg,
t. xiv, 1856, p. 246).

Pour more volcanoes, mentioned in part by Admiral
Liitke, and in part by Postels, namely the Apalsk, still
smoking, to the south-east of the village of Bolscheretski,
the Schischapinskaja Sopka (lat. 55° 11'), the cone of fvres-
towsk (lat. 56° 4'), near the Kliutschewsk group, and the
Uschkowsk, I have not cited in the foregoing series from
want of more exact specification. The central mountain-
range of Kamtschatka, especially in the plain of Baidaren,
lat. 57° 20', eastward of Sedanka, presents (as if it bad been
"the field of an ancient crater of about four wersts, that is

TRUE VOLCANOES. 367

to say, the same number of kilometres, in diameter"), the
remarkable geological phenomenon of effusions of lava and
scoriae from a blistery and often brick-coloured volcanic
rock, which in its turn has penetrated through fissures in the
earth, at the greatest possible distance from any frame-
work of raised cones (Erman, Beise, Bd. iii, s. 221, 228
and 273 ; Buch, lies Canaries p. 454). The analogy is here
very striking with what I have already circumstantially
explained regarding the Malpays, the problematic fields of
debris in the elevated plain of Mexico (see page 315).

V. ISLANDS OF EASTERN ASIA.

From Torres Strait, which, in the 10th degree of southern
latitude, separates New-Guinea and Australia, and from
the smoking volcano of Flores to the most northern of the
Aleutian Isles (lat. 55°) there is a multitude of islands,
for the most part volcanic, which, considered in a general
geological point of view, it would be somewhat difnciilt, on
account of their genetic connection, to divide into separate
groups, and which increase considerably in circumference
towards the south. Beginning at the north we first observe
that the curved series60 of the Aleutians, issuing from the
American peninsula of Alaska, connect the old and the new
continents together by means of the island Attu, near
Copper Island and Behring's Island, while to the south they
close in the waters of Behring's Sea. From Cape Lopatka,
at the southern extremity of the peninsula of Karntschatka,
we find succeeding each other in the direction from north to
south first, the Archipelago of the Kuriles, bounding on the
east the Saghalien or Ochotsk Sea, rendered famous by La
Perouse, next Jesso, probably in former times connected
with the island of Krafto61 (Saghalin, or Tschoka), and

60 See Dana's remarks on the curvatures of ranges of islands, whose
convexity in the South Sea is almost always directed towards the
Bouth or south-east, in the United States' Explor. Exped. by Wilkes,
vol. x (Geology by James Dana), 1849, p. 419.

61 The island of Saghalin, Tschoka, or Tarakai, is called by the Ja-
panese mai-iners Krafto (written Karafuto). It lies opposite the mouth
of the Amoor (the Black River, Saghalian Ula), and is inhabited by the
Ainos, a race mild in disposition, dark in colour, and sometimes rather
hairy. Admiral Kruseiistern was of opinion, as were also previously

368 COSMOS

lastly the tri-insular empire of Japan, across the narrow
Strait of Saugar (Niphon, Sitkok and Kiu-Siu, according to
Siebold's admirable map, between 41° 32' and 30° 18'). From
the volcano of Kliutschewsk, the northernmost on the east
coast of the peninsula of Kamtschatka, to the most southern
Japanese volcano-island of Tanega-Sima, in the Van Die-
men's Channel, explored by Krusenstern, the direction of
the igneous action as indicated in the numerous rents of the
earth's crust, is precisely from north-east to south-west. The
range is carried on by the island of Jakuno-Sima, on which
a conical mountain rises to the height of 5838 feet (1780
metres), and which separates the two straits of Yan Die-
men and Colnet, — by the Linschote Archipelago of Siebold,
— by Captain Basil Hall's sulphur island, Lung-Huang-
Schan, and by the small group of the Loo-choo and Majico-
sima, which latter approaches within a distance of 92
geographical miles the eastern margin of the great island of
the Chinese coasts, Formosa or Tay-wan.

the companions of La Pe'rouse (1787) and Broughton (1797), that
Saghalin was connected with the Asiatic continent by a narrow, sandy
isthmus (lat. 52° 50 ; but from the important Japanese notices com-
municated by Franz von Siebold, it appears that, according to a chart
drawn up in the year 1808, by Mamia Rinso, the chief of an Imperial
Japanese commission, Krafto is not a peninsula, but an island sur-
rounded on all sides by the sea (Ritter, Erdkunde von Asien, vol. ii,
p. 488). The conclusion of Mamia Rinso has been very recently com-
pletely verified, as mentioned by Siebold, when the Russian fleet lay
at anchor in the year 1855, in the Baie de Castries (lat. 51° 29') near
Alexandrowsk, and consequently to the south of the conjectured
isthmus, and yet was able to retire into the mouth of the Amoor (lat.
52° 24'). In the narrow channel in which the isthmus was formerly
supposed to be, there were in some places only 5 fathoms water. The
island is beginning to acquire some political importance on account of
the proximity of the great stream of Amoor or Saghalin. Its name,
pronounced Karafto or Krafto, is a contraction of Kara-fu-to, which
signifies, according to Siebold, " the island bordering on Kara." In
the Japano-Chinese language Kara denotes the most northerly part of
China (Tartary), and fu, according to the learned writer just men-
tioned, signifies " lying close by." Tschoka is a corruption of Tsyokai,
and Tarakai originates from a mistake in the name of a single village
called Taraika. According to Klaproth (Asia Polyglotla, p. 301),
Taraikai, or Tarakai, is the native Aino name of the whole island.
Compare Leopold Schrenk's and Captain Bernard Wittingham's re-
marks in Petermann's Geogr. Mittheilungen, 1856, s. 176 and!84. See
also Perry, Exped. to Japan, vol. i, p. 468.

TRUE VOLCANOES. 369

Here at Formosa (N. lat. 25°— 26°) is the important
point where, instead of the lines of elevation from N.E.
to S.W. those in the direction from north to south com-
mence, and continue nearly as far as the parallel of 5° or 6°
of southern latitude. They are recognizable in Formosa
and in the Philippines (Luzon and Mindanao) over a space
of fully twenty degrees of latitude, intersecting the coasts,
sometimes on one side and sometimes on both, in the direc-
tion of the meridian. They are likewise visible on the east
coast of the great island of Borneo, which is connected by
the So-lo Archipelago with Mindanao, and by the long
narrow island of Palawan with Mindoro. So also in the
western portions of the Celebes, with their varied outline,
and Gilolo, and lastly (which is especially remarkable) in
the longitudinal fissures on which, at a distance of 1400
geographical miles eastward of the group of the Philippines
and in the same latitude, the range of volcanic and coral
islands of Marian or the Ladrones have been upheaved.
Their general direction62 is north and 10° east.

Having pointed out in the parallel of the carboniferous
island of Formosa, the turning point at which the direction
of the Kuriles from N.E. to S.W. is changed to that from
north to south, I must now observe that a new system of
fissures commences to the south of Celebes and the south
coasts of Borneo, which, as we have already seen, is cut
from east to west. The greater and lesser Sunda islands,
from Timor-lant to West-Bali, follow chiefly for the space
of 18° of longitude, the mean parallel of 8° south lati-
tude. At the western extremity of Java the mean axis
runs somewhat more towards the north, nearly E.S.E. and
W.N.W., while from the Strait of Sunda to the southern-
most of the Nicobar Isles the direction is from S.E. to
N.W. The whole volcanic fissure of elevation (E. to \V.
and S.E. to N.W.), has consequently an extent of about
2700 geographical miles, or eleven times the length of the

82 Dana, Geoloyy of the Pacific Ocean, p. 16. Corresponding with
the meridian lines of the south-east Asiatic island-world, the shore*
of Cochin-China from the gulph of Tonquiu, those of Malacca from
the gulph of Siam, and even those of New Holland south of the 25th
degree of lat., are for the most part cut off as it were in the directioa
from north to south.

VOL. V. 2 B

370 COSMOS.

Pyrenees. Of this space, if we disregard the slight devia-
tion towards the north in Java, 1620 miles belong to the
east and west direction, and 1080 to the south-east and
north-west.

Thus do general geological considerations on form and
range lead uninterruptedly in the island-world on the
east coast of Asia (over the immense space of 68° of
latitude) from the Aleutian Isles and Behring's Sea to the
Moluccas and the Great and Little Sunda lies. The greatest
variety in the configuration of the land is met with in the
parallel-zone of 5° north and 10° south latitude. It is very
remarkable how generally the line of eruption in the larger
portions is repeated in a neighboring smaller portion. Thus
a long range of islands lies near the south coast of Sumatra
and parallel to it. We find the same appearances in the
smaller phenomena of the mineral veins as in the greater
ones of the mountain ranges of whole continents. Accom-
panying debris running by the side of the principal vein,
and secondary chains (chaines accompagnantes) lie frequently
at considerable distances from each other. They indicate
similar causes and similar tendencies of the formative action
in the folding in of the crust of the earth. The conflict of
powers in the contemporaneous openings of fissures in op-
posite directions appears sometimes to occasion strange
formations in juxtaposition, as may be seen in the Molucca
Islands, Celebes, and Kilolo.

After developing the internal geological connection of the
East and South A.siatic insular system, in order not to deviate
from the long-adopted, though somewhat arbitrary, geo-
graphical divisions and nomenclature, we place the southern
limit of the Eastern Asiatic insular range (the turning point)
at Formosa, where the line of direction runs off from the
N.E.—S.W. to the N.— S., in the 24th degree of north
latitude. The enumeration proceeds again from north to
south, beginning with the eastern, and more American,
Aleutian Islands.

The Aleutian Isles, which abound in volcanoes, include, in
the direction from east to west, the Fox Islands, among
which are the largest of all, Unimak, Unalaschka, and
TJmnak ; — the Andrejanowsk Isles, of which the most
famous are Atcha, with three smoking volcanoes, and the

TRUE VOLCANOES. 371

great volcano of Tanaga, already delineated by Sauer; —
the Rat Islands, and the somewhat distant islands of B'ynia,
among which, as has been already observed, Attu forms the
connecting link to the Commander group (Copper and
Behring's Isles) near Asia. There seems no ground for the
often-repeated conjecture that the range of continental vol-
canoes in the direction of NN.E. and SS.W. on the penin-
sula of Kamtschatka first commences where the volcanic
fissure of upheaval in the Aleutian Islands intersects the
peninsula beneath the ocean, the Aleutian-fissure thus form-
ing, as it were, a channel of conduction. According to
Admiral Liitke's chart of the Kamtschatkan Sea (Behring's-
Sea) the island of Attu, the western extremity of the Aleu-
tian range, lies in lat. 52° 46', and the non-volcanic Cop-
per and Behring's Islands in lat. 54° 30' to 55° 20', while the
volcanic range of Kamtschatka commences under the paral-
lel of 56° 40' with the great volcano of Schiwelutsch, to the
west of Cape Stolbowoy. Besides, the direction of the
fissures of eruption is very different, indeed, almost opposite.
The highest of the Aleutian volcanoes, on Unimak, is 8076
feet, according to Liitke. Near the northern extremity of
Umnak, in the month of May, 1796, there arose from the
sea. under very remarkable circumstances, which have been
admirably described in Otto von Kotzebue's " Entdeckungs-
reise" (Bd. ii, s. 106), the island of Agaschagokh (or St.
Johannes Theologus) which continued burning for nearly
eight years. According to a report published by Krusen-
stern, this island was, in the year 1819, nearly sixteen
geographical miles in circumference, and was nearly 2240 feet
high. On the island of Unalaschka the proportions of the
trachyte, containing much hornblende, of the volcano of
Matuschkin (5474 feet) to the black porphyry (?) and the
neighbouring g anite, as given by Chamisso, would deserve
to be investigated by some scientific observer acquainted
with the conditions of modern geology, and able to examine
carefully the mineralogical character of the different kinds
of rocks. Of the two contiguous islands of the Pribytow
group, which lie isolated in the Kamtschafckan sea, that of
St. Paul is entirely volcanic, abounding in lava and pumice,
while St. George's Island, on the contrary, contains only
granite and gneiss.

2 B 2

372 COSMOS.

According to the most exact enumeration we yet possess,
the range of the Aleutian Isles, stretching over 960 geo-
graphical miles, seems to contain above thirty-four volcanoes,
the greater part ol them active in modern historical times.
Thus we see here (in 54° and 60° latitude, and 160°—
196° west longitude) a stripe of the whole floor of the
ocean between two great continents in a constant state of
formative and destructive activity. How many islands in
the course of centuries, as in the group of the Azores,
may there not be near becoming visible above the surface of
the ocean, and how many more which, after having long
appeared, have sunk either wholly or partially unobserved !
For the mingling of races, and the migration of nations,
the range of the Aleutian Islands furnishes a channel from
thirteen to fourteen degrees more southerly than that of
Behring's Straits, by which the Tchutches seem to have
crossed from America to Asia, and even to the other side of
the river Anadir.

The range of the Kurile Islands, from the extreme point
of Kamtschatka to Cape Brought on (the northernmost pro-
montory of Jesso) in a longitudinal space of 720 geographi-
cal miles, exhibits from eight to ten volcanoes, still for the
most part in a state of ignition. The northernmost of
these, on the island of Alaid, known for its great eruptions
in the years 1770 and 1793, is well worthy of being accu-
rately measured, its height being calculated at from 12,000
to 15,000 feet. The much less lofty Pic Sarytshew (4193
feet according to Horner) on Mataua, and the southernmost
Japanese Kuriles, Urup, Jetorop, and Kunasiri, have also
been very active volcanoes.

We now come in the order of succession of the volcanic
range to Jesso, and the three larger Japanese Islands, re-
specting which the celebrated traveller, Herr von Siebold,
has kindly communicated to me a large and important work
for assistance in my Cosmos. This will serve to correct what-
ever was defective in the notices which I borrowed from the
great Japanese Encyclopedia in my Fraqmens de Geologic
et de Climatologie Asiatiques (t. i, pp. 217 — 234), and in
Asie Centrale (t. ii, pp. 540—552).

The large island of Jesso, which is very quadrangular in
its northern portion (lat. 41^° to 45jJ°), separated by the

TRUE VOLCANOES. 373

Strait of Saugar, or Tsugar, from Niphon, and by that of la
Perouse from the island of Krafto (Ksra-fu-to), bounds by
its north-east cape the Archipelago of the Kuriles ; but not
far from the North west Cape Komanzow on Jesso, which
stretches a degree and a half more northward in the strait
of La Perouse. lies, in latitude 45° 11', the volcanic Pic de
Langle (5350 feet) on the little island of Bisiri. Jesso
itself seems also to be intersected by a range of volcanoes,
from Broughton's Southern Volcano Bay nearly all the way
to the North Cape, a circumstance the more remark-
able as, on the narrow island of Krafto which is almost
a continuation of Jesso, the naturalists of la Perouse's ex-
pedition found in the JBaie de Castries fields of red porous
lava and scoriae. On Jesso itself Siebold counted seventeen
conical mountains, the greater number of which appear to
be extinct volcanoes. The Kiaka, called by the Japanese
Usuga-Take, or Mortar-mountain, on account of a deeply-
nollowed crater, and the Kajo-hori are both said to be
still in a state of ignition. (Commodore Perry noticed
two volcanoes from Volcano Bay near the harbour of En-
derrno, lat. 42° 17'). The lofty Man ye ( Krusenstem's
conical mountain Pallas) lies in the middle of the island of
Jesso, nearly in lat. 44°, somewhat to the E.N.E. of Bay
Strogonow.

" The historical books of Japan mention only six active
volcanoes before and since our era, namely, two on the island
of Niphon, and four on the island of Kiu-siu. The vol-
canoes of Kiu-siu, the nearest to the peninsula of Corea.
reckoning them in their geographical position from south to
north, are (1) the volcano of Mitake, on the islet of
Sayura-sima, in the bay of Kagosima (province of Satsuma),
which lies open to the south, lat. 3 1° 33', long. 130° 41';
(2) the volcano Kirisima (lat. 31° 45') in the district
of Naka, province of JFinga ; 3rd, the volcano A so jama, in
the district Aso (lat. 32° 45'), province of Figo ; 4th,
the volcano of Yunzen, on the peninsula of Simabara (lat.
32° 44'), in the district of Takaku. The height of this
volcano, amounts, according to a barometrical measurement,
only to 1253 metres, or 4110 English feet, so that it is
scarcely a hundred feet higher than Vesuvius (Rocca del
Palo). The most violent eruption of the volcano of Vunzen

374

COSMOS.

on record is that of February 1793. Vunzen and Aso jama
both lie east-south-east of Nangasaki."

" The volcanoes of the great island of Niphon, again
reckoning from south to north, are (1) the volcano of Fusi
jama, scarcely 16 geographical miles distant from the
southern coast, in the district Fusi, province of Suruga
(lat. 35° 18', long. 138° 35'). Its height, measured in the
same way as the volcano of Yunzen, or Kiusiu, by some
young Japanese, instructed by Siebold, amounts to 3793
metres, or 12,441 feet ; it is therefore fully 320 feet higher
than the Peak of Teneriffe, with which it has been already
compared by Kampfer (Wilhelm Heine, Reise nach Japan,
1856, Bd. ii, s. 4). The upheaval of this conical moun-
tain is recorded in the fifth year of the reign of Mikado VI
(286 years before our era) in these (geognostically remark-
able) words : — ' In the country of Omi a considerable tract
of land sinks, an inland lake is formed, and the volcano
Fusi makes its appearance ' The most violent historically
recorded eruptions within the Christian era are those of
799, 800, 863, 937, 1032, 1083, and 1707 ; since the latter
period the mountain has been tranquil. 2nd. The volcano
of Asama jama, the most central of the active volcanoes in
the interior of the country, distant 80 geographical miles
from the south-south-cast, 52 miles from the north-north-
west coast, in the district of Saku (province of Sinano),
lat. 36° 22', long. 138° 38'; thus lying between the meri-
dians of the two capitals, Mijako and Jeddo. The Asama
jama had an eruption as early as the year 864, contempora-
neously with the Fusi jama ; that of the month of July
1783 was particularly violent and destructive. Since that
time the Asama jama has maintained a constant state of
activity.

"Besides these volcanoes two other small islands with
smoking craters have been observed by European mariners,
namely, 3rd. The small island of Iv6gasima or Ivosima (sima
signifies island, and ivo sulphur ; ga is merely an affix mark-
ing the nominative), Krusenstern's lie du Volcan, south of
Kiu-siu, in Van Diemen's Strait, 30°.43'jN". lat. and 130° 18'
E. long., distant only fifty-four miles from the above-men-
tioned volcano of Mitake ; the height of the volcano is 2364
feet (715 met). This island is mentioned by Linschoten so

TRUE VOLCANOES. 375

early as 1596 in these words : i The island has a volcano,
which is a sulphur, or fiery mountain.' It occurs also on
the oldest Dutch sea-charts under the name of Vulcanus
(Fr. von Siebold, Atlas vom Jap. Seiche, Tab. xi). Kru-
senstern saw it smoking in 1804, as did Captain Blake in
1838, and Gue"rin and De la Roche Poncie in 1846. The
height of the cone, according to the latter navigator, is 2345
feet (715 met.) The rocky islet mentioned as a volcano by
Landgrebe in the NaturgeschicJite der VulJcane (Bd. i,
s. 355), and which, according to Kampfer, is near Firato
(Firando), is imdoubtedly Ivo-sima, for the group to which
Ivo-sima belongs is called Kiusiu ku sima, i.e., the nine
islands of Kiusiu, and not the ninty-nine islands. A group
of this description occurs near Firato, northward of Naga-
saki, and no where else in Japan. (4) The island of Ohosima
(Barneveld's Island; Krusenstern's He de Vries), which is
considered part of the province of Idsu, on Niphon, and
lies in front of the Bay of Yodavara, in 34° 42' N. lat. and
139° 26' E. long. Broughton saw smoke issuing from the
crater in 1797, a violent eruption of the volcano having
taken place a short time previous. From this island a range
of smaller volcanic isles stretches out in a southerly direction
as far as Fatsi-syo (33° 6' N. lat.), and continues as far as the
Bonin Islands (26° 30' N. lat. and 142° 5' E. long.), which,
according to A. Postels (Liitke, Voyage autour du Monde
dans les annees 1826 — 29, t. iii, p. 117) are likewise vol-
canic and are subject to veiy violent earthquakes."

" These, then, are the eight volcanoes historically known
to be active in Japan Proper, in and near the islands of
Kiusiu and Niphon. But in addition to these volcanoes a
range of conical mountains must also be cited, some of which,
marked by very distinct and often deeply indented craters,
appear to be volcanoes long since extinct. One of these is
the conical mountain of Kaimon, Krusenstern's Pic Homer
in the southernmost part of the island of Kiusiu, on the
coast of Yan Diemen's Strait, in the province of Satsum
(lat. 31° 9'), scarcely six geographical miles SSW. from
the active volcano of Mitake. Another is the Kofusi, or
Little Fusi, on Sikok ; and another is on the islet of
Kutsuriasima. in the province of Ijo (lat. 33° 45'), on the
eastern coast of the great straits of Suvo Nada or Yan der

376 COSMOS.

Capellen, which separate the three great portions of the
Japanese empire, Kiusiu, Sikon, and Niphon. On the
latter, or principal island, nine such conical mountains, pro-
bably trachytic, are reckoned, the most remarkable of which
are, the Sira jama (or White Mountain) in the province of
Kaga, lat. 36°5', and the Tsyo Kai-san, in the province of
Deva (lat. 39°10'), both of which are considered loftier than
the southerly volcano of Fusi jama, which is upwards of
12,360 feet high. Between these two, in the province of
Jetsigo, lies the Jaki jama (or Flame Mountain, lat. 3G°o3').
The two northernmost conical mountaims in the Saugar Strait,
in sight of the great island of Jesso, are, (1) The Ivaki
jama, called by Krusenstern, whose illustrations of the geo-
graphy of Japan have gained him immortal honour, the Pic
Tilesius (lat. 40° 42') ; and (2) The Jake jama (the Burning
Mountain, lat. 41° 20'), in Nambu, at the north-eastern ex-
tremity of Niphon, with igneous eruptions from the remotest
times."

In the continental portion of the neighbouring peninsula
of Corea, or Korai (which, in the parallels of 34° and
34^°, is almost united with Kiusiu by the islands Tsu sima
and Iki), notwithstanding its great similarity in form to the
peninsula of Kanitschatka, no volcanoes have hitherto been
discovered. The volcanic action seems to be confined to
the adjoining islands. Thus, in the year 1007, the island-
volcano of Tsininura, called by the Chinese, Tanlo, rose from
the sea. A learned Chinese, named Tien-kong-chi, was sent
to describe the phenomenon and to execute a picture of it.63
But it is especially on the island of Se-he-sure (the Quel-
paerts of the Dutch) that the mountains exhibit everywhere
a volcanic conical form. The central mountain rises, ac-
cording to Broughfcon and La Perouse, to the height of 6395
feet. How many volcanic effects may there not yet remain
to be discovered in the Western Archipelago, where the
King of the Coreans styles himself the Sovereign of 10,000
Islands !

From the Pic Homer (Kaimon ga take) on the west side
of the southern extremity of the Kiusiu, in the Japanese
tri-insular empire, there stretches out in a curve which lies

63 Compare the translations of Stanislas Julien from the Japanese
Encyclopaedia in my Asie Centrale, t. ii, p. 551.

TRUE VOLCANOES. 377

open towards the west, a small range of volcanic islands,
comprising, first, between the Var Diemen and Colnet
Straits, the Jakuno sima and the Tanega sima; second
south of the Strait of Colnet in the Li nschot en-group64 of
Siebold (the Archipel Cecile of Captain G-uerin), which ex-
tends as far as the parallel of 29°, the island of Suvase sima,
the volcano island of Captain Belcher (lat. 29°39' and long.
129° 41') rising, according to De la Roche Poncie, to a height
of 2800 feet (855 met.) ; third, Basil Hall's sulphur island,
the Tori-sima, or Bird Island, of the Japanese, the Lung-
hoang-shan of Pere Gaubil, in lat. 27° 51' and long. 128° 14',
as fixed by Captain De la Roche Poncie in 1848. As this
island is also called Iwosima, care must be taken not to con-
found it with its more northerly namesake in Van Diemen's
Straits. It has been admirably described by Captain Basil Hall.
Between the parallel of 26J and 27° of latitude comes in suc-
cession the group of the Lieu-thieu, or Loo-choo Islands, as
the natives call them, of which Klaproth published a separate
map in 1824, and more to the south-west the small Archi-
pelago of Majicosima, which approaches the great island of
Formosa, and is considered by me to be the closing point of
the eastern Asiatic islands. Close to the east coast of Formosa
(lat. 24°) a great volcanic eruption in the sea was observed
by Lieutenant Boyle in 1853 (Commodore Perry, Exped. to
Japan, vol. i, p. 500). Among the Benin Islands ( Buna-
sima of the Japanese, lat. 26|° to 27f° and long. 142° 15')
that called Peel's Island has several craters abounding in
sulphur and scorise, which do not appear to have been long
extinct (Perry, i, pp. 200 and 209).

VI. ISLANDS OF SOUTHERN ASIA.

We comprehend under this division Formosa (Tayvan),
the Philippines, the Sunda Islands and the Moluccas. Klap-
roth first made us acquainted with the volcanoes of Formosa
by information extracted from Chinese sjurces, which are
always so copious in 'their descriptions of nature.06 They

64 Compare Kaart van den Zuid-en Zuidwest-Kust van Japan door
F. von Siebold, 1851.

® Compare my Fragment de Geologie et de Climmologie Asiatiques,
t i, p. 82, which appeared immediately after my return from my

378 COSMOS.

are four in number, and of these the Chy-kang (Red Moun-
tain), whose crater contains a hot-water lake, has experi-
enced great igneous eruptions. The small Baschi Islands
and the Babuyans, which so late as 1831, according to
Meyen's testimony, experienced a violent eruption of fire,
connect Formosa with the Philippines, of which the smallest
and most broken islands abound most in volcanoes. Leo-
pold von Buch enumerates nineteen lofty isolated conical
mountains upon them, which in the country are called vol-
canes, though probably some of them are closed trachytic
domes. Dana is of opinion that in southern Luzon there
are now only two active volcanoes, — that of Taal, which
rises in the Laguna de Bongbong, with an encircling escarp-
ment which incloses another lagoon (see page 243) ; and in
the southern portion of the peninsula of Camarines the vol-
cano of Albay, or Mayon, which the natives call Isaroe.
The latter, which is 3197 feet high, experienced great erup-
tions in the years 1800 and 1814. In the northern portion
of Luzon granite and mica- slate, and even sedimentary
formations together with coal are diffused.66

The far-stretching group of the Soolo (Solo) islands, which
are fully 100 in number, and which connect Mindanao and
Borneo, is partly volcanic, and partly intersected by coral-
reefs. Isolated unopened, trachytic, cone-shaped peaks are
indeed often called Vulcanes by the Spaniards.

If we carefully examine all that lies to the south of the
fifth degree of north latitude (to the south of the Philippines),
between the meridians of the Nicobars and the north-west
of New Guinea, thus taking in the Sunda Islands, great and
Siberian expedition, and the Asie Centrale, in which the opinion ex-
pressed by Klaproth, and which I formerly adopted, respecting the
probability of the connection of the snowy mountains of the Himalaya
with the Chinese province of Yunan and with Nanling north westward
of Canton, has been confuted by me. The mountains of Formosa,
upwards of 11,000 feet high, as well as Ta-yu-ling which bounds
Fukian to the westward, belong to the system of meridian fissures in
Upper Assam, in the country of the Burmese, and in the group of
the Philippines.

66 Dana's Geology, in the Explor. Exped., vol. x, p. 540 — 545 ; Ernest
Hofmann, Geogn. Beob. auf der Reise von Otto v. Kotzebue, p. 70 ; Leop.
de Buch, Description Physique des lies Canaries, pp. 435—439. See
the large and admirable chart of the Islas Filipinas, by the Pilot Don
Antonio Morati (Madrid, 1852), in two plates.

TRUE VOLCANOES. 379

email, and the Moluccas, we shall find as the result, given in
the great work of Dr. Junghuhn, that " in a circle of islands
which surround the almost continental Borneo, there are
109 lofty fire-emitting mountains, and 10 mud-volcanoes."
This is not merely an approximate calculation, but an actual
enumeration.

Borneo, the Giava Maggiore of Marco Polo,67 has hitherto
furnished us with no certain proofs of the existence of any
active volcano upon it ; but, indeed, it is only a few narrow
strips of the shore that we are acquainted with (on the
north-west side as far as the small coast- island of Labuan,
and as far as Cape Balambangan; on the west coast at
the mouth of the Pontianak ; and on the south-eastern
point in the district of Banjermas-Sing, on account of the
gold, diamond and platinum washings). It is not even be-
lieved that the highest mountain of the whole island, and
perhaps even of the whole South Asiatic island-world, the
double-peaked Kina Bailu at the northern extremity, dis-
tant only thirty-two geographical miles from the Pirate-
coasts, is a volcano. Captain Belcher makes it 13,695 feet
high, which is nearly 4000 feet higher than the Gunung
Pasaman (Ophir) of Sumatra.68 On the other hand, Rajah

6' Marco Polo distinguishes (Part iii, cap. 5 and 8) Giava Minore
(Sumatra), where he remained for five months, and where he describes
the elephants, which were not to be found in Java itself (Humboldt,
Examen. Grit, de VHist. de la Georg., t. ii, p. 218), from what he had
before described as Giava (Maggiore), la quale, secondo dicono i mari-
nai, che bene to sanno, e Visola piu grande che sia al mondo, — (which
as the sailors say, who know it well, is the largest island in the world.
This assertion is even to this day true. From the outlines of the chart
of Borneo and Celebes by James Brooke and Captain Rodney Mundy,
I find the area of Borneo 51,680 square geographical miles, nearly
equal to that of the island of New Guinea, but only one-tenth of the
continent of New Holland. Marco Polo's account of the great quantity
of gold and treasure which the "Mercanti di Zaiton e del Mangi" ex-
ported from thence, shows that by Giava Maggiore he meant Borneo,
(as did also Martin Behaim on the Niirnberg globe of 1492, and Johann
Ruysch in the Roman edition of Ptolemy, dated 1508, which is so
important for the history of the discoveiy of America).

68 Captain Mundy's chart (coast of Borneo Proper, 1847,) gives, it is
true, 14,000 English feet. See a doubt of this datum in Junghuhn's
Java, Bd. ii, s. 580. The colossal Kina Bailu is not a conical moun-
tain. In shape it much more resembles the basaltic mountains which
occur under all latitudes, and which form a long ridge with two
terminal summits.

380 COSMOS.

Brooke mentions a much lower mountain in the province of
Sarawak, whose name, Gunung Api (Fire Mountain in the
Malay tongue) as well as the scorite which lie around it,
lead to the conclusion that it was once volcanically active.
Large deposits of gold- sand between quartz-veins, the abun-
dance of tin washed down on both shores of the rivers, and
the feldspathic porphyry69 of the Carambo Mountains, indi-
cate a great extension of what are called primitive and
transition rocks. According to the only certain information
which we possess from a geologist (Dr. Ludwig Horner,
son of the meritorious Zurich astronomer and circumnavi-
gator of the globe), there are found in the south-eastern
portion of Borneo united in several profitably worked wash-
ings, precisely as in the Siberian Ural, gold, diamonds, plati-
num, osmium, and iridium (but not yet palladium). Forma-
tions of serpentine, euphotide, and syenite, lying in great
proximity, belong to a range of rocks 3411 feet high, that
of the Ratuhs Mountains.70

The still active volcanoes on the remaining three great
Sunda Islands are reckoned by Junghuhu as follows :— On
Sumatra from six to seven, on Java from twenty to twenty-
three, on Celebes eleven, and on Flores six. Of the vol-
canoes of the island of J&va we have already (see above
page 298) treated in detail. In Sumatra, which has not
hitherto been completely investigated, out of nineteen con-
ical mountains of volcanic appearance there are six still
active.71 Those ascertained to be so are the following : —
The Gunung Indrapura, about 12,256 feet in height, accord-
ing to angles of altitude measured from the sea, and pro-
bably of equal height with the more accurately measured
Semeru or Maha-Meru on Java; — the Gunung Pasaman,
called also Ophir (9602 feet), with a nearly extinguished
crater, ascended by Dr. L. Horner ; — the sulphureous Gun-
ung Salasi, with eruptions of ashes in 1833 and 1845 ; —
the Gunung Merapi (9751 feet), also ascended by Dr. L.
Horner, accompanied by Dr. Korthal, in the year 1834, the

69 Brooke's Borneo and Celebes, vol. ii, pp. 382, 384, aad 386.

70 Homer, in the Verhandelingen van het Bataviaasch Genootschap
vcm Kunsten en Wetensckappen, Deel xvii (1839), s. 281 ; Asie Centrale,
t. iii, pp. 534—537.

71 Junghuhn, Java, Bd. ii, e. 809 ; (Battalander, Bd. i, s. 39).

TRUE VOLCANOES. 3&1

active of all the volcanoes of Sumatra, tind not to be
confounded with the two similarly named mountains of
Java ;72 — the Chiming Ipu, a smoking truncated cone ; — and
the Gunung Dernpo, in the inland country of Benkula,
reckoned at 9940 feet high.

Four islets forming trachytic cones, of which the Pic Kecata
and Panahitam (Prince's Island) are the highest, rise above
the sea in the Strait of Sunda, and connect the volcanic range
of Sumatra with the crowded field of Java, and in like man-
ner the eastern extremity of Java, with its volcano of Idjen,
forms, through the medium of the active volcanoes Gunung
Batur and Gunung Agung on the neighbouring island of
Bali, a connection with the long chain of the smaller Sunda
Islands. Here again the range is continued eastward from
Bali, by the smoking volcano of Rindjani on the island of
Lombok, 12.363 feet high, according to the trigonometrical
measurement of M. Melville de Carnbee ; — by the Temboro
(5862 feet) on the Sumbava, or Sambava, whose eruption of
ashes and pumice in April, 1815, obscured the surrounding
atmosphere, and was one of the greatest which history has
recorded;73 — and by six conical mountains still partially
smoking, on Flores

The large and many armed island of Celebes contains six
volcanoes, which are not yet all extinct ; they lie all together
on the narrow north-eastern peninsula of Menado. Beside
it spout out streams of hot melted sulphur, into the orifice
of one of which, near the road from Sender to Lamovang, a
great traveller and intrepid observer, Count Carlo Vidua,
my Piedmontese friend, sank and met his death from the
burns he received. As the small island of Banda in the
Moluccas consists of the volcano of Guning Api, which was
active from 1586 to 1824, and is about 1812 feet high, in
the same way the larger island of Ternate is likewise formed
by a single conical mountain, 5756 feet high, the Gunung
Gama Lama, whose violent eruptions from 1838 to 1849,
after more than a century and a half of entire quiescence are
described at ten different periods. During the eruption of
the 3rd February, 1840, according to Junghuhn, a stream of
lava poured out of a fissure near the fort of Toluko, and

72 See page 300, note 86. » Java, Bd. ii, B. 818—828.

S82 COSMOS.

flowed down to the shore,74 " partly issuing in the form of
a connected and thoroughly molten stream, and partly
consisting of glowing fragments which rolled down and were
forced along the plain by the weight of the succeeding
masses." If to the more important volcanic cones here in-
dividually mentioned we add the numerous small island vol-
canoes which cannot be here noticed, the total number of
the igneous mountains situated to the southward of the
parallel of Cape Serangami on Mindanao, one of the Philip-
pines, and between the meridians of the north-west Cape of
New Guinea on the east and of the Nicobar and Andaman
groups on the west, amounts, as has been already stated, to
the large number of 109.76 This calculation is made in the
belief that *' on Java forty-five volcanoes, for the most part
cone-shaped, and provided with craters, may be counted."
Of these, however, only 21, and only from 42 to 45,
of the whole number of 109, are recognized as now active,
or as having been so, at any period within the reach of
history. The mighty Pic of Timor formerly served like
Stromboli as a light-house to mariners. On the small island
of Pulu Batu (called also P. Komba), a little to the north
of Floris, a volcano was seen in 1850 to pour a stream of
glowing lava down to the sea-shore. The same thing was
observed in 1812, and again in the spring of 1856, in
respect to the Pic on the greater Sangir Island, between
Magindanao and Celebes. Junghuhn doubts whether the
famous conical mountain of Yavani or Ateti, on Amboina,
ejected anything more than hot mud in 1674, and considers
the island at present as only a solfatara. The great group
of the South Asiatic Islands is connected by the division of
the Western Sunda Islands with the Nicobar and Andaman,
Isles of the Indian Ocean, and by the division of the Mo-
luccas and Philippines with the Papuas, the Pellew Islands
and Carolinas of the South Sea. We shall first, however,
proceed with the less numerous and more dispersed groups
of the Indian Ocean.

VII. THE INDIAN OCEAN.

This comprehends the space between the west coast of
» Junghuhn's Java, vol. ii, pp. 840—842. ?5 Ibid, p. 853.

TRUE VOLCANOES. 383

the peninsula of Malacca, or of the Birman country to the
east coast of Africa, thus inclosing in its northern division
the Bay of Bengal and the Arabian and Red Seas. We
pursue the chain of volcanic activity in the Indian Ocean in
the direction from north-east to south-west.

Barren Island, in the Bay of Bengal, a little to the east
of the great Andaman Island (lat. 12° 15'), is correctly con-
sidered an active cone of eruption, issuing out of a crater of
upheaval. The sea forces its way through a narrow opening
and fills an internal basin. The appearance presented by
this island, which was discovered by Horsburgh in 1791, is
exceedingly instructive for the theory of the formation of
volcanic structures. We sec here in a complete and per-
manent form what nature exhibits in only a cursory way at
Santorin, and at other points of the earth's surface.76 The
eruptions in November 1803 were, like those of Sangay in
the Cordilleras of Quito, very distinctly periodical, recurring
at intervals often minutes (Leop. von Buch in the Abhandl.
der Berl. Akademie, 1818—1819, s. 62).

The island of Narcondam, to the north of Barren Island,
has likewise exhibited volcanic action at a former period, as
has also the cone-mountain of the island of Cheduba, which
lies more to the north, near the shore of Arracan (10° 52').
(Silliman's American Journal, vol. xxxviii, p. 385).

The most active volcano, judging from the frequency of
the lava-eruptions, not only in the Indian Ocean but in
almost the whole of the south hemisphere between the meri-
dians of the west coast of New Holland and the east coast
of America, is that on the island of Bourbon in the group
of the Mascareignes. The greater part of the island, parti-
cularly the western portion and the interior, is basaltic.
Recent veins of basalt, with little admixture of olivine, run
through the older rock, which abounds in olivine ; beds of
lignite are also enclosed in the basalt. The culminating
points of the Mountain Island are the Gros Mornr and the
Trois Salazes, the height of which La Caille over-estimated
at 10,658. The volcanic action is now limited to the southern-
most portion, the " Grand pays brule." The summit of the

7fi Leop. v. Buch, in the Abhandl. der Akad. der Wiss. zu Berlin,
1818 and 1819, s. 62; Lyell, Princ. of Geology. (1853), p. 447, where a
fine representation of the volcano is given.

384 COSMOS.

volcano of Bourbon, which Hubert describes as emitting,
nearly every year, two streams of lava which frequently ex-
tend to the sea, is, according to Berth's measurement, 8000
feet high.77 It exhibits several cones of eruption which have
received distinct names, and which alternately send forth
eruptions. The eruptions from the summit are infrequent.
The lavas contain glassy feld-spar, and are therefore rather
trachytic than basaltic. The shower of ashes frequently con-
tains olivine in long, fine threads, a phenomenon which like-
wise occurs at the volcano of Owhyhee. A violent eruption
of these glassy threads, covering the whole island of Bour-
bori, occurred in the year 1821.

All that we know of the great neighbouring terra incog-
nita of Madagascar is the extensive dispersion of pumice at
Tintingue, opposite the French island of St. Marie, and the
occurrence of basalt, to the south of the bay of Diego Suarez,
near the northernmost Cap d'Ambre, surrounded by granite
aud gneiss. The southern central-ridge of the Ambohist-
raene Mountains is calculated (though with little certainty)
at about 11,000 feet. Westward of Madagascar, in the
northern outlet of the Mozambique Channel, the largest
of the Comoro Islands has a burning volcano (Darwin,
Coral Reefs, p. 122).

The small volcanic island of St. Paul (38° 38'), south of
Amsterdam, is considered volcanic, not only on account of
its form, which strongly reminds one of that of Santorin,
Barren Island, and Deception Island, in the group of the
New Shetland Isles, but likewise on account of the repeat-
edly ob&erved eruptions of fire and vapour in modern times.
The very characteristic drawing given by Yalentyn in hia
work on the Banda Islands, relative to the expedition of
Willein de Vlaming (November 1696) corresponds exactly,
as do also the statements of the latitudes, with the repre-
sentations in the atlas of Macartney's expedition, and Cap-
tain Blackwood's survey (1842). The crater-shaped, circular
bay, nearly an English mile across, is everywhere surrounded
by precipitate rocks which fall perpendicularly in the in-
terior, with the exception of a narrow opening, through
which the sea enters at flood-tide ; while those which form

77 Bory de St. Vincent, Voyage aux Quatre Isles d'Afrique, t. iL
p. 429.

TRUE VOLCANOES. 385

the margin of the crater fall away externally with a gentle
slope.78

The island of Amsterdam which lies 50' of latitude farther
towards the north (37° 48') consists, according to Valentyn's
representation, of a single, well-wooded, somewhat rounded
mountain, from the highest ridge of which rises a small
cubical rock, almost the same as at the Cofre de Perote on
the higher plains of Mexico. During the expedition of D'En-
trecasteaux (March 1792), the island was seen for two whole
days entirely enveloped in flames and smoke. The smell of
the smoke seemed to indicate the combustion of wood and
earth ; columns of vapour were, indeed, thought to rise here
and there from the ground near the shore, but the natural-
ists who accompanied the expedition were decidedly of
opinion that the mysterious phenomenon could by no means
be ascribed to an eruption 79 of the high mountain, like that

73 Valentyn, Beschryving van Oud en Nieuw Oost Indien, Deel iii,
(1726), p. 70 ; Het Eyland St. Paulo. (Compare Lyell, Princ. p. 446).

79 "\Ve were unable," says D'Entrecasteaux, " to form any conjecture
as to the cause of the burning on the island of Amsterdam. The
island was in flames throughout its whole extent, and we recognized
distinctly the smell of burnt wood and earth. We had felt nothing to
lead us to suppose that the fire was the effect of a volcano" (t. i,
p. 45). A few pages before, he says, " We remarked, however, as we
sailed along the coast, from which the flames were rather distant,
little puffs of smoke which seemed to come from the earth like jets ;
yet we could not distinguish the least trace of fire around them,
though we were very close to the laud. These jets of smoke which
appeared at intervals, were considered by the naturalists of the expedi-
tion as certain proofs of subterranean fire." Are we to conclude from
this that there were actual combustions of earth, — conflagrations of
lignite, the beds of which, covered with basalt and tufa, occur in such
abundance on volcanic islands (as Bourbon, Kerguelen-land, and Ice-
land) ? The Surtarbrand, on the latter island, derives its name from
the Scandinavian myth of the fire-giant Surtr causing the conflagra-
tion of the world. The combustion of earth, however, causes no flame
in general. As in modern times the names of the islands Amsterdam
and St. Paul are unfortunately often confounded on charts, I would
here observe, in order to prevent mistakes in ascribing to one observa-
tions which apply to the other, they being very different in formation
though lying almost under one and the same meridian, that originally
(as early as the end of the 17th century) the south island was called
St. Paul and the northern one Amsterdam. Vlaming, their discoverer,
assigned to the first the latitude of 38°40', and to the second thatof 37°48'
south of the equator. This corresponds in a remarkable manner with
VOL. V. "2 C

386 COSMOS.

of a volcano. More certain evidences of former genuine
volcanic action on the island of Amsterdam may be found in
the calculation made by D'Entrecasteaux a century later on the occa-
sion of the expedition in search of La Pgrouse ( Voyage, t. i, p. 43 —45).
namely, for Amsterdam, according to Beautemps Beaupre, 37° 47' 46"
(long. 77° 71'), for St. Paul 38° 38'. This near coincidence must be con-
sidered accidental, as the points of observation were certainly not ex-
actly the same. On the other hand Captain Blackwood in his Ad-
miralty chart of 1842 gives 38°" 44' and longitude 77° 37' for St. Paul.
On the charts given in the original editions of the voyages of the im-
mortal circumnavigator Cook, those for instance of the first and second
expedition ( Voyage to the South Pole and Round the World, London,
1777, p. 1), as well as of the third and last voyage (Voyage to the
Pacific Ocean, published by the Admiralty, London, 1784, in 2nd edi-
tion, 1785), and even of all the three expeditions (A General Chart,
exhibiting the Discoveries of Captain Cook in his Third and Two Pre-
ceding Voyages, by Lieut. Henry Roberts), the island of St. Paul is
very correctly laid down as the most southernly of the two ; but in
the text of the voyage of D'Entrecasteaux (t. i, p. 44), it is mentioned
by way of censure (whether with justice or not I am unable to say,
although I have sought after the editions in the libraries of Paris,
Berlin, and Gb'ttingen), "that on the special chart of Cook's last expe-
dition the island of Amsterdam is set down as more to the south than
St. Paul." A similar reversal of the appellations, quite opposed to
the intention of the discoverer, Willem de Vlamiug, was frequent in
the first third of the present century, as for example on the older and
excellent maps of the world by Arrowsmith and Purdy (1833), but
there was more than a special chart of Cook's third voyage operating
to cause it. There was, 1st, the arbitrary entry on the maps of Cox
and Mortimer ; 2nd, the circumstance that, in the atlas of Lord Mac-
artney's voyage to China, though the beautiful volcanic island repre-
sented smoking is very correctly named St. Paul, under Lit. 38° 42',
yet it is absurdly added, " commonly called Amsterdam," and what
is still worse, in the narrative of the voyage itself, Staunton and.
Dr. Gillau uniformly called this " island still in a state of inflamma-
tion " Amsterdam, and, they even add (p. 226, after having given the
correct latitude in p. 219) " that St. Paul is lying to the northward of
Amsterdam ;" and 3rdly, there is the same confusion of names by
Barrow (Voyage to Cochin China in the Years 1792 and 1793, pp. 140 —
157), who also gives the name of Amsterdam to the southern island,
emitting smoke and flames, assigning to it at the same time the lati-
tude 38° 42'. Malte Brun (Precis de la Geographic Universelle, t. v,
1817, p. 146), very properly blames Barrow, but he errs in also
blaming, M. de Rossel and Beautemps-Beaupre\ Both of the latter
writers give as the latitude of the island of Amsterdam, which is the
only one they represent, 37° 47', and that of the island of St. Paul,
because it lies 50' more to the south, 38° 38' ( Voy. de D' Entrecastreaux,
1808, t. 1, pp. 40 — 46), and to show that the design represents the
true island of Amsterdam, discovered by Willem de Vlaming, Beau-

TRUE VOLCANOES. 387

the beds of pumice-stone (uitgebranden puimsteen), mention
of which is made so early as by Valentyn, according to
Vlaming's Ship Journal of 1696.

To the south-east of the Cape of Good Hope lie Marion's,
or Prince Edward's Island (47° 2'). and Possession Island
(lat. 46° 28' and long. 51° 56'), forming part of the Crozet
group. Both of them exhibit traces of former volcanic
action,— small conical hills,80 with eruption-openings sur-
rounded by columnar basalt.

More eastward, and almost in the same latitude, we come
to Kerguelen's island (Cook's Island of Desolation), for the
first geological account of which we are indebted to the suc-
cessful and important expedition of Sir James Ross. In the
harbour called by Cook Christmas Harbour (lat. 48° 41',
long. 69° 2'), basaltic lavas, several feet thick, are found en-
closing the fossil trunks of trees ; there also is seen the sin-
gular and ^picturesque Arched Rock, a natural passage through
a narrow projecting wall of basalt. In the neighbourhood
are conical-mountains, the highest of which rise to 2664 feet,
with extinct craters, — masses of green-stone and porphyry,
traversed ky beds of basalt, — and amygdaloid with dnisv
masses of quartz at Cumberland Bay. The most remarkable
of all are the numerous beds of coal, covered with trap- rock
(dolerite, as at Meissner in Hesse ?), of a thickness of
from a few inches to four feet at the outcrop.81

If we take a general survey of the Indian Ocean, we shall
find the north-westerly extremity of the Sunda range in
Sumatra, which is curved, carried on through the Nicobars
and the Great and Little Andamans, while the volcanoes of
Barren Island, Narcondam, and Cheduba, almost parallel

temps-Beaupre adds in his atlas a copy of the thickly-wooded island
of Amsterdam from Valentyn. I may here observe that the cele-
brated navigator, Abel Tasman having in 1642, along with Middel-
burg, called the island of Tonga-Tabu (lat. 21-i°) in the Tonga group,
by the name of Amsterdam (Burney, Chronolog. Hist, of the Voyages
and Discoveries in the South Sea or Pacific Ocean, Part iii, pp. 81 and
437) ; he has also been sometimes erroneously cited as the discoverer
of Amsterdam and St. Paul in the Indian Ocean. See Leidenfroet,
Ilhtor. Handwortenbuch, Bd. v, s. 310.

80 Sir James Ross, Vogage in the boutnem and Antarctic Reg long
vol. i, pp. 46, and 50 — 56.

» Ibid. p. 63—82.

2c 2

388 COSMOS.

to the coasts of Malacca and Tenasseriin, run into the
eastern portion of the Bay of Bengal. Along the shores of
Orissa and Coromandel, the eastern portion of the bay is
destitute of islands, the great island of Ceylon bearing, like
that of Madagascar, more of the character of a continent.
Opposite the western shore of the Indian peninsula (the
elevated plain of Neilgherry and the coasts of Ganara and
Malabar) a range of three archipelagos lying in a direction
from north to south, and extending from 14° north to 8°
south latitude (the Laccadives, the Maldives, and the Chagos)
is connected by the shallows of Sahia de Malha and Car-
gados Carajos with the volcanic group of the Mascareignes
and Madagascar. The whole of this chain, so far as can be
seen, is the work of coral-polypes, — true Atolls, or lagoon-
reefs ; in accordance with Darwin's ingenious conjecture
that at this part a large extent of the floor of the ocean
forms, not an area of upheaval, but an area of subsidence.

VIII. THE SOUTH SEA, OR PACIFIC.

If we compare that portion of the earth's surface now
covered with water with the aggregate area of the terra
firma, (nearly82 in the proportion of 2.7 to 1), we cannot but
be astonished in a geological point of view at the small
number of volcanoes which still continue active in the
oceanic region. The South Sea, the superficies of which is
nearly one-sixth greater than that of the whole terra firma
of our planet, — which in the equinoctial region, from the
archipelago of Galapagos to the Pellew Islands, is nearly
two-fifths of the whole circumference of the earth in breadth,
— exhibits fewer smoking volcanoes, fewer openings through
which the interior of the planet still continues in active
communion with its atmospheric envelope than does the
single island of Java. Mr. James Dana, the talented geo-
logist of the great American exploring expedition (1838 —
1842), under the command of Charles Wilkes, basing his
views on his own personal investigations, aided by a careful
comparison of all previous reliable observations, and espe-

82 The result of Prof. Rigaud'a " weighings " at Oxford, according to
Halley'a old method. See my Asie Centrale, t. i, p. 189.

TRUE VOLCANOES. 389

cially by a comprehensive examination of the different opi-
nions on the forms, the distribution and the axial direction
of the island groups, on the character of the different kinds of
rocks, and the periods of the subsidence and upheaval of ex-
tensive tracts of the floor of the ocean, has the indisputable
merit of having shed a new light over the island-world of
the South Sea. In availing myself of his work, as well as
of the admirable writings of Charles Darwin, the geologist of
Captain Fitzroy's expedition (1832 — 1836), without always
particularizing them, I trust that the high respect in which
I have for so many years held those gentlemen, will secure
me from the chance of having my motives misinterpreted.

It is my intention to avoid altogether the divisional terms
of Polynesia, Micronesia, Melanesia, and Malaisia,83 which
are not only extremely arbitrary, but founded on totally
different principles drawn from the number and size, or the
complexion and descent of the inhabitants, and to com-
mence the enumeration of the still active volcanoes of the
South Sea with those which lie to the north of the equator.
I shall afterwards proceed in the direction from east to
west to the islands situated between the equator and the
parallel of 30° south latitude. The numerous basaltic and
trachytic islands, with their countless craters, formerly at
different times eruptive, must on no account be said to be
indiscriminately scattered.84 It is admitted with respect to
the greater number of them that their upheaval has taken

s3 D'Urville, Voy. de la Corvette I' Astrolabe, 1826—1829, Atlas, pi. i.
— 1st, Polynesia is considered to contain the eastern portion of the
South Sea (the Sandwich Islands, Tahiti, and the Tonga Archipelago ;
and also New Zealand) ; 2nd, Micronesia and Melanesia form the west-
ern portion of the South Sea ; the former extends from Kauai, the
westernmost island of the Sandwich group, to near Japan and the
Philippines, and reaches south to the equator, comprehending the
Marians (Ladrones), the Carolinas and the Pellew Islands ; 3rd, Me-
lanesia, so called from its dark-haired inhabitants, bordering on the
Malaisia to the north-west, embraces the small archipelago of Viti, or
Feejee, the New Hebrides and Solomon's Islands; likewise the larger
islands of New Caledonia, New Britain, New Ireland, and New
Guinea. The terms Oceania and Polynesia, often so contradictory iu
a geographical point of view, are taken from Malte-Brun (1813) and
from Le*soii (1 828).

84 " The epithet scattered, as applied to the islands of the ocean (in
the arrangement of the groups) conveys a very incorrect idea of thei*

390 COSMOS.

place on widely extended fissures and submarine mountain-
chains, which run in directions governed by fixed laws of
region and grouping, and which, just as we see in the conti-
nental mountain chains of Central Asia, and of the Caucasus,
belong to different systems ; but the circumstances which
govern the area over which at any one particular time the
openings are simultaneously active, probably depend, from
the extremely limited number of such openings, on entirely
local disturbances to which the conducting fissures are sub-
jected. The attempt to draw lines through three now
simultaneously active volcanoes, whose respective distances
amount to between 2400 and 3000 geographical miles
asunder, without any intervening cases of eruption (I refer
to three volcanoes now in a state of ignition, — Mouna Loa,
with Kilauea on its eastern declivity, — the cone-mountain
of Tanna, in the new Hebrides ; and Assumption Island in
the North Ladrones), would afford us no information in re-
gard to the general formation of volcanoes in the basin of
the South Sea. The case is quite different if we limit our-
selves to single groups of islands, and look back to remote,
perhaps pre-historic, epochs when the numerous linearly
arranged, though now extinct, craters of the Ladrones
(Marian Islands), the New Hebrides and the Solomon's
Islands were active, but which certainly did not become

positions. There is a system in their arrangement as regular as in
the mountain heights of a continent, and ranges of elevation are indi-
cated, as grand and extensive as any continent presents." Geology,
by J. Dana, United States' Exploring Expedition, under command of
Charles Wilkes, vol. x, (1849) p. 12. Dana calculates that there are
in the whole of the South Sea, exclusive of the small rock-islands,
about 350 basaltic or trachytic and 290 coral islands. He divide?
them into twenty-five groups, of which nineteen in the centre
have the direction of their axis N. 50° — 60° W., and the remaining
N. 20° — 30° E. It is particularly remarkable that these numerous
islands, with a few exceptions, such as the Sandwich Islands and New
Zealand, all lie between 23° 23' of north and south latitude, and that
there is such an immense space devoid of islands eastward from the
Sandwich and the Nukahiva groups as far as the American shores of
Mexico and Peru. Dana likewise draws attention to a circumstance
which forms a contrast to the insignificant number of the now active
volcanoes, namely, that if, as is probable, the Coral Islands, when lying
between entirely basaltic islands, have likewise a basaltic foundation,
the number of submarine and subae'rial volcanic openings may be esti-
mated at more than a thousand (pp. 17 and 24).

TRUE VOLCANOES. 391

gradually extinguished in a direction either from south-
east to north-west or from north to south. Though I
here name only volcanic island-chains of the high seas, yet
the Aleutes and other true coastian islands are analogous
to them. General conclusions as to the direction of a cool-
ing process are deceptive, as the state of the conducting
medium must operate temporarily upon it, according as it is
open or interrupted.

Mouna Loa, ascertained by the exact measurement8' of
the American exploring expedition under Captain Wilkes
to be 13,758 feet in height, and consequently 1600 feet
higher than the Peak of Teneriffe, is the largest volcano of
the South Sea Islands, and the only one that still remains
really active in the whole volcanic archipelago of the Hawaii
or Sandwich Islands. The summit-craters, the largest
of which is nearly 13,000 feet in diameter, exhibit in
their ordinary state a solid bottom, composed of hardened
lava and scoriae, out of which rise small cones of eruption,
exhaling vapour. The summit openings are on the whole
not very active, though in June 1832 and in January
1843, they emitted eruptions of several weeks' duration, and
even streams of lava of from 20 to 28 geographical miles in
length, extending to the foot of Monna Kea. The fall (in-
clination) of the perfectly connected flowing stream86 was
chiefly 6U, frequently 10°, 15°, and even 25°. The conforma-
tion of the Mouna Loa is very remarkable from the circum-
stance of its having no cone of ashes, like the Peak of
Teneriffe, Cotopaxi, and so many other volcanoes ; it is
likewise almost entirely deficient in pumice87 though the
blackish-grey, and more trachy tic than basaltic, lavas of the

85 See Cosmos, vol. v, p. 250, note 35.

so Dana, Geology of the U. St. Explor. Exped., pp. 208 and 210.

87 Dana, pp. 193 and 201. The absence of cinder-cones is likewise
very remarkable in those volcanoes of the Eifel which emit streams of
lava. Reliable information, however, received by the Missionary Dib-
ble from the mouths of eye-witnesses, proves that an eruption of ashes
may notwithstanding occur from the summit-crater of Mouna Loa, for
he was told that, during the war carried on by Kamehameha against
the insurgents in the year 1789, an eruption of hot ashes, accompanied
by an earthquake, enveloped the surrounding country in the darkness
of night (p. 183). On the volcanic glass threads (the hair of the god-
dess Pele, who before she went to settle at Hawaii inhabited the now

592 COSMOS.

summit abound in felspar. The extraordinary fluidity of
the lavas of Mouna Loa, whether issuing from the summit-
crater (Mokna-weo-weo) or from the sea of lava (on the
eastern declivity of the volcano, at a height of only 3969 feet
above the sea), is testified by the glass threads, sometimes
smooth and sometimes crisped or curled, which are dispersed
by the wind all over the island. This hair glass, which is
likewise thrown out by the volcano of Bourbon, is called
Pele's hair by the Hawaiians, after the tutelary goddess of
the countiy.

Dana has ably demonstrated that Mouna Loa is not the
central volcano of the Sandwich Islands, and that Kilauea is
not a solfatara.88 The basin of Kilauea is 16,000 feet (about
2-| geographical miles) across its long diameter, and 7460
feet across its shorter one. The steaming, bubbling, and
foaming mass which forms the true lava-pool does not,
however, under ordinary circumstances, fill the whole of
this cavity, but merely a space whose long diameter mea-
sures 14,000 feet and its breadth 5000 feet. The descent to
the edge of the crater is gi"aduated. This great phenomenon
produces a wonderful impression of silence and solemn re-
pose. The approach of an eruption is not here indicated
by earthquakes or subterranean noises, but merely by a
sudden rising and falling of the surface of the lava, some-
times to the extent of from 300 or 400 feet up to the
complete filling of the whole basin. If, disregarding the
immense difference in size, we were to compare the gigantic
basin of Kilauea with the small side-craters, (first described
by Spallanzani), on the declivity of Stromboli at four-fifths
of the height of the mountain, the summit of which has

extinct volcano of Hale-a-Kala — or the House of the Sun — on the island
of Mani). See pp. 179 and 199—200.

88 Dana, p. 205. "The term Solfatara is wholly misapplied. A
solfatara is an area with steairing fissures and escaping sulphur vapours,
and without proper lava ejections ; while Kilauea is a vast crater with
extensive lava ejections and no sulphur, except that of the sulphur
banks, beyond what necessarily accompanies, as at Vesuvius, violent
volcanic action." The structural frame of Kilauea, the mass of the
great lava-basin, consists also, not of beds of ashes or fragmentary
rocks, but of horizontal layers of lava, arranged like lime-stone. Dana,
p. 193. (Compare Strzelecki, Phys. Descr. of New South Wales, 1845,
p. 105-111).

TRUE VOLCANOES. 393

no opening — that is to say, with basins of boiling lava of
from 30 to 200 feet in diameter only — we must not forget
that the fiery gulfs on the slope of Stromboli throw out
ashes to a great height, and even pour out lava. Though
the great lava-lake of Kilauea (the lower and secondary
crater of the active volcano of Mouna Loa) sometimes
threatens to overflow its margin, yet it never actually runs
over so as to produce true streams of lava. These occur by
currents from below, through subterranean channels, and
the formation of new eruptive-openings at a distance of
from 16 to 20 geographical miles, consequently at points
very much lower than the basin. After these eruptions,
occasioned by the pressure of the immense mass of lava
in the basin of Kilauea, the fluid surface sinks in the
basin.89

Of the two other high mountains of Hawaii, Mouna Lea
and Mouna Hualalai, the former is, according to Captain
Wilkes, 190 feet higher than Mouna Loa. It is a conical
mountain on whose summit there no longer exists any
terminal-crater, but only long extinct mounds of scoriae.
Mouna Hualalai* is fully 10,000 feet high, and is still burn-
ing. In the year 1801 an eruption took place, during which
the lava reached the sea on the western side. It is to
the three colossal mountains of Loa, Kea and Hualalai,
which rose from the bottom of the sea, that the island of
Hawaii owes its origin. In the accounts given of the nume-
rous ascents of Mouna Loa, among which that of the expedi-

89 This remarkable sinking of the surface of the lava is confirmed
by the relations of numerous voyagere, from Ellis, Stewart, and Doug-
las to the meritorious Count Strzelecki, Wilkes's expedition and the
remarkably observant Missionary Coan. During the great eruption of
June, 1840, the connection of the rise of the lava in the Kilauea with
the sudden inflammation of the crater of Arare, situated so far below
it, was most decidedly shown. The disappearance of the lava poured
forth from Arare, its renewed subterranean course, and final re-ap-
pearance in greater quantity, do not quite admit of an absolute con-
clusion as to identity because numerous lava-yielding longitudinal
fissures opened simultaneously below the line of the floor of the
Kilauea basin. It is likewise very worthy of observation, as bearing
on the internal constitution of this singular volcano of Hawahi, that
in June, 1832, both craters, that of the summit and that of Kilauea,
poured out and occasioned streams of lava, so that they were simul-
taneously active. (Compare Dana, pp. 184, 188, 193, and 196).

394 COSMOS.

tior of Captain "Wilkes was based on investigations of twenty-
eight days' duration, mention is made of falls of snow with a
degree of cold from 23 to 17^- F. above zero, and of single
patches of snow, which could be distinguished with the aid
of the telescope at the summit of the volcano, but nothing
is ever said of perpetual snow.90 I have already observed in
a former part of this work that the Mouna Loa (13,758 feet)
and the Mouna Kea (13,950 feet) are respectively more than
1000 and 821 feet lower than the lowest limit of perpetual
snow as found by me in the continental mountains of Mexico
under 19 4° latitude. On a small island the line of perpetual
snow should lie somewhat lower, on account of the less ele-
vated temperature of the lower strata of air in the hottest
season of the tropical zone, and on account of the greater
quantity of water held in solution in the upper atmosphere.

The volcanoes of Tafoa* and Amargura*1 in the Tonga-
group are both active, and the latter had a considerable
eruption of lava on the 9th of July 1847.91 It is extremely
remarkable and is in entire accordance with the stories of
the coral animals avoiding the shores of volcanoes either
at the time or shortly before in a state of ignition, that the
Tonga islands of Tafoa and the cone of Kao, which abound
in coral-reefs are entirely destitute of those creatures.92

Next follow the volcanoes of Tanna* and Ambrym,* the
latter westward of Mallicollo in the archipelago of the New
Hebrides. The volcano of Tanna, first described by Rein-
hold Forster, was found in a full state of eruption on Cook's
discovery of the island in 1774. It has since remained con-
stantly active. Its height being only 458 feet, it is one of
the lowest fire-emitting cones, along with the volcano of
Mendana, hereafter to be noticed, and the Japanese volcano
of Kosima. There is a great, quantity of pumice on Mall-
icollo.

Matthew's Rock ; * a very small smoking rock-island,
about 1183 feet high, the eruption of which was observed

90 Wilkes, pp. 114, 140, and 157; Dana, p. 221. From the per-
petual transmutation of the r and the I, Mauna Loa is often written
Koa, and Kilauea, Kirauea.

91 Dana, pp. 25 and 138.

92 Dana, Geology of the U. States Exploring Exped., p. 138. (See
Darwin, Structure of Coral Reefs, p. 60).

TRUE VOLCANOES. 395

by D'Urville in January 1828. It lies eastward of the
southern point of New Caledonia.

The volcano of Tinakoro* in the group of Yanikoro or
Santa Cruz.

In the same archipelago of Santa Cruz, fully 80 geo-
graphical miles NN.W. of Tinakoro, the volcano* seen by
Mendana so early as 1595, rises out of the sea to a height of
about 213 feet (lat. 10° 23' S.). Its eruptions have some-
times been periodical, occurring every ten minutes, and at
other times, as on the occasion of the expedition of D'Entre-
casteaux, the crater itself and the column of vapour were
uudistinguishable from each other.

In the Solomon' s-group the volcano of the island of
Sesarga* is in a state of ignition. On the coast of Guadal-
canal', in this neighbourhood, and therefore also at the
south-east end of the long range of islands towards the
Vanikoro or Santa Cruz group, volcanic eruptive action
has likewise been observed.

In the Ladrones, or Marian Islands, at the north end of
the range, which seems to have been upheaved from a meri-
dian fissure, Guguan,* Pagon,* and the Volcan grande of
Asuncion are said to be still in a state of activity.

The direction of the coasts of the small continent of New
Holland, and particularly the deviation from that direction
seen in the east coast in 25° south latitude (between Cape Her-
vey and Moreton Bay), seem to be reflected in the zone of the
neighbouring eastern islands. The great southern island of
New Zealand, and the Kermadec and Tonga groups stretch
from the south-west to the north-east, while, on the other
hand, the northern portion of the north island of New Zea-
land (from the Bay of Plenty to Cape Oton), New Caledonia
and New Guinea, the New Hebrides, the Solomon's Isles,
New Ireland and New Britain run in a direction from south-
east to north-west, chiefly N. 48° W. Leopold von Buch9*
first drew attention to this relation between continental
masses and neighbouring islands in the Greek Archipelago
and the Australian Coral Sea. The islands of the latter sea,
too, are not deficient, as both Forster (Cook's companion) and
La Billardiere formerly observed, in granite and mica-slate,

53 Ldop. von Buch, Description phys. des iles Canaries, 1836, pp. 393
and 403—405.

396 COSMOS.

the quart zose rocks formerly called primeval. Dana has like-
wise collected them on the northern island of New Zealand,
to the west of Tipuna, in the Bay of Islands.94

New Holland exhibits only on its southern extremity
(Australia Felix), at the foot and to the south of the Gram-
pian Mountains, fresh traces of former igneous action, for
we learn from Dana that a number of volcanic cones and de-
posits of lava are found to the north-west of Port Phillip,
as also in the direction of the Murray river (Dana, p. 453).

On New Britain* there are at least three cones on the
west coast, which have been observed within the historical
era, by Tasman, Dampier, Carteret and La Billardiere, in a
state of ignition and throwing out lava.

There are two active volcanoes on New Guinea,* on the
north-eastern coast, opposite New Britain and the Admiralty
Islands/ which abound in obsidian.

In New Zealand, of which the geology of the north island
at least, has been illustrated by the important work of Ernst
Dieffenbach, and the admirable investigations of Dana, ba-
saltic and trachytic rocks at various points break through the
generally diffused plutonic and sedimentary rocks. This ex-
ample is the case in a very limited area near the Bay of Islands
(lat. 35° 2'), where the ash-cones, crowned with extinct craters,
Turoto and Poerua rise ; and again, more to the south-east,
(between 37-^-° and 39^-° lat.), where the volcanic floor runs
quite across the centre of the north island, a distance of more
than 160 geographical miles from north-east to south-west,
from the Bay of Plenty on the east to Cape Egmont on the
west. This zone of volcanic action here traverses, (as we
have already seen it to do on a much larger scale in the Mexi-
can Continent) in a diagonal fissure from north-east to south-
west, the interior chain of mountains which runs lengthwise
in a north and south direction, and which seems to give its
form to the whole island. On the ridge of this chain stand,
as it were, at the points of intersection, the lofty cone of Ton-
gariro* (6198 feet), whose crater is found on the top of the
ash-cone, Bidwill, and, somewhat more to the south, Ruapahu

94 See Dana, ibid. p. 438 — 446, and on the fresh traces of ancient vol-
canic action in New Holland, pp. 453 and 457 ; also on the many basal-
tic columns in New South Wales and Van Diemen's Land, p. 495 — 510 ;
and E. de Strzelecki, Phys. Descr. of New South Wales, p. 112.

TRUE VOLCANOES. 397

(9006 feet). The north-east end of the zone is formed in
the Bay of Plenty (lat. 38-^), by a constantly smoking solfa-
tara, the island -volcano of Puhia-i-wakati*95 (White Island).
Next follow to the south-west, on the shore itself, the extinct
volcano of Putawaki (Mount Edgecombe), 8838 feet high,
probably the highest snowy mountain on New Zealand, and
in the interior, between Mount Edgecombe and the still
burning Tongariro,* which has poured fourth some streams
of lava, a lengthened chain of lakes, partly consisting of
boiling water. The lake of Taupo, which is surrounded by
beautiful glistening leucite and sanidine sand, as well as by
mounds of pumice, is nearly 24 geographical miles long, and
lies in the centre of the north island of New Zealand, at an
elevation, according to Dieffenbach, of 1337 feet above the
surface of the sea. The ground for two English square
miles round, is entirely covered with solfataras, vapour-holes,
and thermal-springs, the latter of which form, as at the Gey-
ser in Iceland, a variety of siliceous precipitates96. West-
ward of Tongariro,* the chief seat of volcanic action, whose
crater still ejects vapours and pumice-stone ashes, and at a dis-
tance of only sixteen miles from the western shore, rises the
volcano of Taranaki (Mount Egmont), 8838 feet high, which
was first ascended and measured by Dr. Ernst Dieffenbach in
November, 1840. The summit of the cone, which in its out-
line more resembles Tolima than Cotopaxi, terminates in a
plain, out of which rises a steep ash-cone. No traces of
present activity, such as are seen on the volcano of the White
Island* and on Tongariro* are visible, nor any connected
stream of lava. The substance composed of very thin scales,
and having a ringing sound, which is seen projecting with
sharp points like fish-bones, from among the scoriae, in the
same manner as on one side of the Peak of Teneriffe, re-
sembles porphyritic schist, or clink-stone.

A narrow, long-extended, uninterrupted accumulation of
island-groups, erupted from north-western fissures, such as

95 Ernest Dieffenbach, Travels in New Zealand, 1843, vol. i, pp. 337,
355 and 401. Dieffenbach calls White Island "a smoking solfatara, but
still in volcanic activity" (pp. 358 and 407), and on the chart, " in con-
tinual ignition."

96 Dana, pp. 445—448 ; Dieffenbach, vol. i, pp. 331 ; 339—341 and 397
On Mount Egmont, bee vol. i, pp. 131 — 157.

398 COSMOS.

New Caledonia and New Guinea, the New Hebrides and
Solomon's Island, Pttcairn, Tahiti and the Pauuiotu Islands,
traverses the great Ocean in the Southern hemisphere in a
direction from west to east, for a length of 5400 geographi-
cal miles, between the parallels of latitude of 12° and 27°,
from the meridian of the east coast of Australia as far as
Easter Island, and the rock of Sala y Gomez. The western
portions of this crowd of islands (New Britain* the New
Hebrides,* Vanikoro* in the Archipelago of Santa Cruz, and
the Tonga-group*) exhibit at the present time in the middle
of the nineteenth century, inflammation and igneous action.
New Caledonia, though surrounded by basaltic and other
volcanic islands, has nevertheless nothing but Plutonic rock, OT
as is the case with Santa Maria98 in the Azores, according to
Leopold von Buch, and with Flores and Graciosa, according
to Count Bedemar. It is to this absence of volcanic action
in New Caledonia, where sedimentary formations with seams
of coal have lately been discovered, that the great develope-
ment of living coral reefs on its shores is ascribed. The Ar-
chipelago of the Viti, or Feedjee Islands is at once basaltic
and trachytic, though distinguished only by hot springs in
the Savu Bay on Vanua Lebu." The Samoa group (Navi-
gator's Islands), north-east of the Feedjee Islands, and nearly
north of the still active Tonga-archipelago is likewise basal-
tic, and is moreover characterised by a countless number
of eruption-craters linearly arranged, which are surrounded
by tufa-beds with pieces of coral baked into them. The Peak
of Tafua, on the island of Upolu, one of the Samoa-group,
presents a remarkable degree of geognostic interest. It must
not, however, be confounded Avith the still enkindled peak of
Tafua, south of Amargura in the Tonga-archipelago. The
Peak of Tafua (2138 feet), which Dana first100 ascended and
measured, has a large crater entirely filled with a thick forest,

9? Darwin, Volcanic Islands, p. 125; Dana, p. 140.

98 L. de Buch, Descr. des I. Can. p. 365. On the three islands here
named, however, phonolite and basaltic rock are also found along with
plutonic and sedimentary strata. But these rocks may have made their
a/ppearance above the surface of the sea on the first volcanic up-heaval
of the island from the bed of the ocean. No traces are said to have
been found of fiery eruptions or of extinct craters.

99 Dana, pp. 343—350.

m Dana, pp. 312, 318, 320 and 323.

TRUE VOLCANOES. 399

and crowned by a regularly rounded ash-cone. There is here
no trace of any stream of lava ; yet on the conical moun-
tain of Apia (2576 feet), which is likewise on Upolu, as
•well as on the Peak of Fao (3197 feet) we meet with fields
of scoriaceous lava (Malpais of the Spaniards), the surface
of which is as it were crimped, and often twisted like a
rope. The lava-fields of Apia contain narrow subterranean
cavities.

Tahiti, in the centre of the Society's Islands, far more tra-
chytic than basaltic, exhibits, strictly speaking, only the ruins
of its former volcanic frame- work, and it is difficult to trace
the original form of the volcano in those enormous masses
looking like ramparts and chevaux-de-frise, with perpendicu-
lar precipices of several thousand feet in depth. Of its two
highest summits, Aorai and Orohena, the former was first
ascended and investigated by that profound geologist Dana.1
The trachytic mountain, Orohena, is said to equal Etna in
height. Thus, next to the active group of the Sandwich
Islands, Tahiti contains the highest rock of eruption in the
whole range of the Ocean between the Continents of Ame-
rica and Asia. There is a felspathic rock on the small
islands of Borabora and Maurua, near Tahiti, designated by
late travellers with the name of syenite, and by Ellis in his
Polynesian researches described as a granitic aggregate of
felspar and quartz, which, on account of the breaking out
of porous, scoriaceous basalt in the immediate neighbour-
hood, merits a much more complete mineralogical investiga-
tion. Extinct craters and lava-streams are not now to be
met with on the Society Islands. The question occurs, —
are the craters on the mountain tops destroyed, — or did the
high and ancient structures, now riven and transformed, con-
tinue closed at the top like a dome, while the veins of basalt
and trachyte poured immediately forth from fissures in the
earth, as has probably been the case at many other points of
the sea's bottom? Extremes of great viscidity or great
fluidity in the matter poured out, as well as the varying
width, or narrowness of the fissures through which the effu-
sion takes place, modify the shapes of the self-forming vol-

1 Leop. von Buch, p. 383 ; Darwin, Vole. hi. p. 25 ; Darwin, Coral
Reefs, p. 138 ; Dana, pp. 286—305 and 364.

400 COSMOS.

came mountain-strata, and where friction produces what is
called ashes and fragmentary sub-division, give rise to small
and for the most part transitory cones of ejection, which are
not to be confounded with the great terminal cinder-cones of
the permanent structural frames.

Close by the Society Islands, in an easterly direction, are
the Low Islands, or Paumotu. These are merely coral islands,
with the remarkable exception of the small basaltic group
of Gambier's and Pitcairn's Islands.2 Volcanic rock, similar
to the latter, is also found in the same parallel (between 25°
and 27° south latitude); 12 60 geographical miles farther to
the east, in the Easter Island (Waihu), and probably also
240 miles farther east, in the rocks Sala y Gomez. On
Waihu, where the loftiest conical peaks are scarcely a thou-
sand feet high, Captain Beechey remarked a range of craters,
none of which appeared, however, to be burning.

In the extreme east towards the New Continent, the range
of the South Sea Island terminates with one of the most
active of all island groups, the Archipelago of Galapagos,
composed of five great islands. Scarcely anywhere else, on
a small space of barely 120 or 140 geographical miles in dia-
meter, has such a countless number of conical mountains and
extinct craters (the traces of former communication between
the interior of the earth and the atmosphere), remained
visible. Darwin calculates the number of the craters at nearly
two thousand. When that talented observer visited the
Galapagos in the expedition of the " Beagle," under Captain
Fitzroy, two of the craters were simultaneously in a state of
igneous eruption. On all the islands, streams of a very
fluid lava may be seen which have forked off into different
channels and have often run into the sea. Almost all are
rich in augite and olivine ; some of which are more of a trachy-
tic character, are said to contain albite3 in large crystals. It

3 Dana, p. 137.

3 Darwin, Vole, hi., pp. 104, 110—112, and 114. When Darwin
says so decidedly that there is no trachyte on the Galapagos, it is be-
cause he limits the term trachyte to the common felspar, i.e. to or-
thoklase, or orthoklase and sanidine (glassy felspar). The enigmati-
cal fragments imbaked in the lava of the small and entirely basaltic
crater of James Island contain no quartz, although they appear to rest
on a plutonic rock (See above, p. 367 et seq). Several of the volcanic
cone-mountains on the Galapagos Islands, have at the orifice a narrow

TRUE VOLCANOES. 401

would be well, in the perfection to which mineralogical
science is now brought, to institute investigations for the
purpose of discovering whether oligoclase is not contained in
these porphyritic trachytes, as at Teneriffe, Popocatepetl and
Chimborazo, or else labradorite, as at Etna and Stromboli.
Pumice is entirely wanting on the Galapagos, as at Vesuvius,
where although it may be present, it is not produced, nor
is hornblende anywhere mentioned to have been found
in them. ; consequently the trachyte formation of Toluca,
Orizaba, and some of the volcanoes of Java, from which Dr.
Junghuhn has sent me some well-selected solid pieces of
lava for examination by Gustav Rose, does not prevail here.
On the largest and most westerly island of the Galapagos
group, Albemarle, the cone-mountains are ranged in a line,
and consequently OR fissures. Their greatest height, however,
reaches only to 4636 feet. The Western Bay, in which the
Peak of Narborough, so violently inflamed in 1825, rises in
the form of an island, is described by Leopold von Buch4 as
a crater of up-heaval, and compared to Santorino. Many
margins of craters on the Galapagos are formed of beds of
tufa, which slope off in every direction. It is a very re-
markable circumstance, seeming to indicate the simul-
taneous operation of some great and wide-spread catas-
trophe, that the margins of all the craters are disrupted or
entirely destroyed towards the south. A part of what in
the older descriptions is called tufa, consists of palagonite
beds, exactly similar to those of Iceland and Italy, as Bun-
sen has ascertained by an exact analysis of the tufas of
Chatham Island.6 This island, the most easterly of the
whole group, and whose situation is fixed by careful astro-
nomical observations by Captain Beechey, is, according to
my determination of the longitude of the city of Quito
(783 44' 8'), and according to Acosta's Mapa de la Nueva
Granada of 1849, 536 geographical miles distant from the
Punta de S. Francisco.

cylindrical, annular addition, exactly like what I saw on Cotopaxi; —
" in some parts the ridge is surmounted by a wall or parapet perpen-
dicular on both sides." Darwin, Vole. Isl. p. 83.

4 L. von Buch, p. 376.

5 Bunsen, in LeonharcCs Jahrb. fur Mineralvgie, 1851, s. 856 ; also
in Poggend, Annalcn der Physik, Bd. Ixxxiii, s. 223.

VOL. V. 2 D

402 COSMOS.

IX. MEXICO.

The six Mexican Volcanoes, Tuxtla,* Orizaba, Popoca-
tepetl,* Toluca, Jorullo* and Colima,* four of which have
been in a state of igneous activity within the historical era,
were enumerated in a former place,6 and described in their
geognostically remarkable relative position. According to
recent investigations by Gustav Rose, the formation of
Chimborazo is repeated in the rock of Popocatepetl, or
Great volcano of Mexico. This rock also consists of oligo-
clase and augite. Even in the almost black beds of
trachyte, resembling pitch-stone, the oligoclase is recognis-
able in veiy small acute-angled crystals. To this same Chim-
borazo and Teiieriffe formation belongs the volcano of Co-
lima, which lies far to the west, near the shore of the South
Sea. I have not myself seen this volcano, but we are indebted
to Herr Pieschel * (since the spring of 1855) for a very
instructive view of the different kinds of rocks collected by

6 See above, pp. 279 — 281.

7 See Pieschel, Ueber die Vullcane von Mexico, in the Geitschrfft fur
allgem. Erdkunde, Bd. vi, 1856, s. 86 and 489—532. The assertion
there made (p. 86) " that never mortal has ascended the steep summit
of the Pico del Fraile," that is to say, the highest Peak of the Volcano
of Toluca, has been confuted by my barometrical measurement made
upon that very summit, (which is, by the way, scarcely 10 feet in width,)
on the 29th September, 1803, and published first in 1807, and again
recently by Dr. Gumprecht in the same volume of the journal above
referred to (p. 489). The doubt raised on this point was the more sin-
gular as it was from this very summit of the Pico del Fraile, whose
tower-like sides are certainly not very easy to climb, and at a height
scarcely 600 feet less than that of Mont Blanc, that I struck off the
masses of trachyte which are hollowed out by the lightning, and which
are glazed on the inside like vitreous tubes. An essay was inserted so
early as 1819 by Gilbert in volume Ix of his Annalen der Physik,
(s. 261) on the specimens placed by me in the Berlin Museum as well
as in several Parisian collections (see also Annales de Chimie et de
Physique, t. xix, 1822, p. 298). In some places the lightning has bored
such regular cylindrical tubes (as much as 3 inches in length,) that they
can be looked through from end to end, and in those cases the rock
surrounding the openings is likewise vitrified. I have also brought
with me pieces of trachyte in my collections, in which the whole sur-
face is vitrified without any tube-like perforation, as is the case at the
little Ararat and at Mont Blanc. Herr Pieschel first ascended the
double-peaked volcano of Colirna, in October, 1852, and reached the

TRUE VOLCANOES. 403

him, as well as for his interesting geological notices on the
volcanoes of the \vhole Mexican highlands, all of which he
has personally visited. The volcano of Toluca, whose
highest summit (the Pico del Frayle), though narrow and
difficult to climb, I ascended on the 29th September, 1803.
and found barometrically to be 15,166 feet high, has a totally
different mineralogical composition from the still active Po-
pocatepetl and the igneous mountain of Colima ; this must
not, however, be confounded with another, still higher sum- -
mit, called the Snow-mountain. The volcano of Toluca
consists, like the Peak of Orizaba, the Puy de Chaumont in
the Auvergne and .^Egina, of a combination of oligoclase
and hornblende. From this brief sketch it will be seen,
and it is well deserving of notice, that in the long range of
volcanoes which extend from ocean to ocean, there are not
two immediately succeeding each other which are of similar
mineralogical composition.

X. THE NORTH-WESTERN DISTRICTS OF AMERICA
(northward of the parallel of Rio Gila) .

In the section which treats of the volcanic action on the
eastern Asiatic Islands,8 particular notice has been drawn
to the bow-like curve in the direction of the fissure of up-
beaval from which the Aleutian Islands have risen, and
which manifests an immediate connection between the
Asiatic and American continents, — between the two volcanic
peninsulas Kamtschatka and Aliaska. At this point is the
outlet, or rather the northern boundary, of a mighty gulf
of the Pacific Ocean, which from the 150 degrees of longi-
tude embraced by it under the equator, narrows itself down
between the terminal points of these two peninsulas to 37C

crater, from which he then saw nothing but sulphuretted-hydrogen va-
pour rising in a cloud ; but Sonneschmid, who vainly attempted to
ascend Colima, in February, 1796, gives an account of an immense
ejection of ashes in the year 1770. In the month of March 1795, on
the other hand, red-hot scorire were visibly thrown out in a column of
fire at night. — " To the north-west of the volcano of Colima, a vol-
canic branch-fissure runs along the shore of the South Sea. Extinct
craters and ancient lava-streams are recognised in what are called the
Volcanoes of Ahuacatlan (on the road from Guadalaxara to San Bias)
and Tepic." (Pieschel, ibid. p. 529).
8 See above, pp. 367—372.

2 D 2

404 COSMOS.

ot* longitude. On the American continent, near the sea-
shore, a number of more or less active volcanoes has become
known to mariners within the last seventy or eighty years,
but this group lay hitherto as it were isolated, and uncon-
nected with the volcanic range of the Mexican tropical
region, or with the volcanoes which were believed to exist
on the peninsula of California. If we include the range of
extinct trachytic cones as intermediate links, we may be
said to have obtained insight into their important geo-
logical connection over a gap of more than 28° of latitude,
between Durango and the new Washington territory, north-
ward of West Oregon. The study of the physical condi-
tion of the earth owes this important step in advance to the
scientifically well-prepared expeditions, which the govern-
ment of the United States has fitted out for the discovery
of the best road from the plains of the Mississippi to the
shores of the South Sea. All the departments of natural
history have derived advantage from those undertakings.
Great tracts of country have been found, in the now ex-
plored terra-incognita of this intermediate space, from very
near the Rocky Mountains on their eastern slope, to a great
distance beyond their western descent, covered with evi-
dences of extinct or still active volcanoes (as for instance
in the Cascade Mountains). Thus, yetting out from New
Zealand and ascending first a long way to the north-west
through New Guinea, the Sunda Islands, the Philippines
and Eastern Asia, to the Aleutians, and then descending
towards the south through the north-western, the Mexican,
the Central American, and South American territories to
the terminating point of Chili, we find the entire circuit
of the basin of the 'Pacific Ocean, throughout an extent of
26,400 geographical miles, surrounded by a range of recog-
nisable memorials of volcanic action. Without entering
into the details of exact geographical bearings and of the
perfected nomenclature, a cosmical view such as this could
never have been obtained.

Of the circuit of the great oceanic9 basin here indicated
(or, as there is but one united mass of water over the

9 The term "Grand Ocean/' used to designate the basin of the
South Sea by that learned geographer, my friend Contre-Amiral de
Fleurieu, the editor of the Introduction Historique au Voyage dt

TRUE VOLCANOES. 405

whole earth, we ought rather to say the circumference of the
largest of those portions oi it which penetrate between con-
tinents) it remains for us now to describe the tract of country
which extends from Rio Gila to Norton's and Kotzebue's
Sounds. Analogies drawn in Euro] e from the Pyrenees or the
Alpine chain, and in South America from the Cordilleras of
the Andes, from South Chili to the fifth degree of north lati-
tude in New Grenada, supported by tanciful delineations in
maps, have propagated the erroneous opinion that the Mexi-
can mountains, or at least their highest ridge, can be traced
along like a wail, under the name of the Sierra Madre, from
south-east to north- west. But though the mountainous
part of Mexico is a mighty swelling of the land running
connectedly in the direction above stated between two seas
to the height of from 5000 to 7000 feet, yet on the
top of this, in the same way as in the Caucasus and in
Central Asia, still loftier ranges of mountains, running in
partial and very various directions, rise to about 15,000 and
17,800 feet. The arrangement of these partial groups,
erupted irom fissures not parallel to each other, is in its
bearings for the most part independent of the ideal axis
which may be drawn through the entire swell of the undu-
lating flattened ridge. These remarkable features in the
formation of the soil give rise to a deception which is
strengthened by the pictorial effect of the beautiful country.
The colossal mountains covered with perpetual snow seem as it
were, to rise out of a plain. The spectator confounds the
ridge of the soft swelling land, the elevated plain, with the
plain of the low lands, and it is only from the change
of climate, the lowering of the temperature, under the same
degree of latitude, that he is reminded of the height to
which he has ascended. The fissure of upheaval, frequently
before mentioned, of the volcano of Anahuac (running in a
direction from east to west between 19° and 19£° lat.) inter-
sects10 the general axis of the swelling land almost at right
angles.

Marchand, confounds the whole with a part, and consequently leads
to misapprehension.

10 On the axes of the greatest elevations and of the volcanoes in
the tropical zone of Mexico, see above pp. 279 and 319. Compare
also Essai Pol. sur la Nouv.-Etp. t. i, pp. 257—268, t. ii, p. 173 ; Vieic*
of Nature, p. 37.

406 COSMOS.

The conformation here described of a considerable portion
of the surface of the earth, which only began to be established
by careful measurements since the year 1803, must not be
confounded with those swellings of the soil which are met
with enclosed between two mountain- chains which bound
them as it were like walls, as in Bolivia at the Lake of
Titicaca, and in Central Asia, between the Himalaya and
Kuen-lim. The former of these, the South American eleva-
tion, which at the same time forms the bottom of a valley,
is on an average according to Pentland, 12.847 feet above the
level of the sea,— the latter, or Thibetian, according to
Captain Henry Strachey, Joseph Hooker, and Thomas
Thomson, is upwards of 14,996. The wish expressed by
me half a century since in my circumstantial " Analyse de
T Atlas Geographique et Physique du Hoyaume de la Nouvelle-
Espagne (§ xiv), that my profile of the elevated plain be-
tween Mexico and Guanaxuato might be continued by
measurements over Durango and Chihuahua as far as
Santa Fe del Nuevo Mexico, is now completely realized.
The length of way, reckoning only one-fourth for the inflec-
tions, amounts to far more than 1200 geographical miles, and
the characteristic feature of this so long unobserved con-
figuration of the earth (the soft undulation of the swelling,
audits breadth in a transverse section, amounting sometimes
to 240 or 280 geographical miles) is manifested by the fact
that the distance (from Mexico to Santa Fe), comprising a
difference of parallels of fully 16° 20; about the same as that
from Stockholm to Florence, is travelled over in four-
wheeled carriages, on the ridge of the table-land, without the
advantage of artificially prepared roads. The possibility
of such a medium of intercourse was known to the Spaniards
so early as the end of the 16th century, when the Viceroy,
the Coude de Monterey,11 planned the first settlements from
Zacatecas.

In confirm ...it-ion of what has been stated in a general way

11 By Juan de Onate, 1594. Memoir of a Tour to Northern Mexico
in 1846 and 1847 by Dr. Wislizenus. On the influence of the con-
figuration of the soil (the wonderful extent of the table-land) on the
internal commerce and the intercourse of the tropical zone with the
north, when once civic order, legal freedom and industry increase ia
these parts, see Essai Pol., t. iv., p. 38, and Dana, p. 612.

TRUE VOLCANOES. 407

respecting the relative heights between the capital of Mexico
and Sante Fe del Nuevo Mexico, I here insert the chief
elements of the barometrical leveJlings. which have been com-
pleted from 1803 to 1847. I take them in the direction
from north to south, so that the most northerly, placed at
the top of the list, may correspond more readily with the
bearings of our charts :12

12 In this survey of the elevations of the soil between Mexico and
Sante Fe del Nuevo Mexico, as well as in the similar, but more im-
perfect table which I have given in the Views of Nature, p. 208, the
letters Ws, Bt, and Ht, attached to the numerals, denote the names of
the observer. Thus, Ws stands for Dr. Wislizeuus, editor of the very
instructive and scientific Memoir of a Tour to Northern Mexico, con-
nected with Col. Doniphan's Expedition, in 1846 and 1847 (Washing-
ton, 1848), Bt the Chief Counsellor of Mines, Burkart, and Ht
for myself. At the time when I was occupied from March 1803
to February 1804 with the astronomical determinations of places
in the tropical part of New Spain, and ventured, from the materials I
could discover and examine, to design a map of that country, of which
my respected friend, Thomas Jefferson, then President of the United
States, during my residence in Washington, caused a copy to be made,
there existed as yet in the interior of the country on the road to
Santa Fe", no determinations of latitude north of Durango (lat. 24° 25').
According to the two manuscript journals of the engineers Rivera,
Laforaaad Mascard, of the years 1724 and 1765, discovered by me in
the archives of Mexico, and which contained directions of the com-
pass and computed partial distances, a careful calculation showed for
the important station of Santa Fe", according to Don Pedro de Rivera,
lat. 36° 12' and long. 105° 52' 30''. (See my Atlas Geogr. et Phys. du.
Me.nquc, Tab. 6, and Essai Pol. t. i, pp. 75 — 82). I took the precaution
in the analysis of my map, to note this result as a very uncertain one
seeing that in the valuations of the distances as well as in the direc-
tions of the compass, uncorrected for the magnetic variation, and
unaided by objects in treeless plains, destitute of human habitations,
over an extent of more than 1200 geographical miles, all the errors
cannot be compensated (t. i, pp. 127 — 131). It happens that the
result here given, as compared with the most recent astronomical
observations, turns out to be much more erroneous in the latitude
than in the longitude, — being in the former about thirty-one and in
the latter scarcely twenty-three minutes. I was likewise fortunate
enough to determine, nearly correctly, the geographical position of the
Lake Timpanogos, now generally called the Great Salt Lake, while the
name of Timpanogos is now only applied to the river which falls into
the little Utah-lake, a fresh water lake. In che language of the Utah
Indians a river is called og-wahbe, and by contraction ogo alone ; tim-
pan means rock, so that Timpan-ogo signifies rock-river (Fremont,
Expl. Exped. 1845, p. 273). Buschmann explains the word timpa as

408 COSMOS.

Santa F6 del Nuevo Mexico (lat. 35° 41'), height 7047
feet, Ws.

Albuquerque13 (lat. 35° 8'), height 4849 feet, Ws.

Paso del Norte14 on the Rio Grande del Norte (lat. 29° 48'),
height 3790 feet, Ws.

Chihuahua (lat. 28° 32'), 4638 feet, Ws.

Cosiquiriachi, G273 feet, Ws.

Mapimi, in the Bolson de Mapimi (lat 25° 54'), 4782 feet.
Ws.

Parras (lat. 25° 32'), 4986 feet, Ws.

Saltillo (lat. 25° 10'), 5240 feet, Ws.

Durango (lat. 24° 25'), 6849 feet, according to Oteiza.

Eresnillo (lat. 23° 10'), 7244 feet, Bt.

Zacatecas (lat. 22° 50'), 9012 feet, Bt.

San Luis Potosi (lat. 22° 8'), 6090 feet, Bt.

Aguas calientes (lat. 21° 53'), 6261 feet, Bt.

derived from the Mexican tetl, stone, while in pa he finds a substantive
termination of the native North-Mexican languages ; to ogo he attri-
butes the general signification of water; see his work,- — Die Spuren
der Aztekitchen Sprache im nordlichen Mexico, s. 354—356 and 351
Compare Expedition to the Valley of the Great Salt Lake of Utah, by
Captain Howard Stansbury, 1852, p. 300, and Humboldt, Views of
Nature, p. 206. My map gives to the Montagnes de Sel gemme, some-
what to the east of the Laguna de Timpanogos, lat. 40° 7', long. 111°
48' 30"; consequently my first conjecture differs 39 minutes in lati-
tude, and 17 in longitude. The most recent determinations of the
position of Santa F6, the Capital of New Mexico, with which I am
acquainted, are 1st, by Lieutenant Emory (1846) from numerous
astronomical observations, lab. 35° 44' 6", and 2nd, by Gregg and
Dr. Wislizenus (1848), perhaps in another locality, 35° 41' 6". The
longitude, according to Emory, is 7h 4' 18", in time from Greenwich,
and therefore 106° 5' in the equatorial circle ; according to Wislizenus,
108° 22' from Paris (New Mexico and California, by Emory, Docum.
No. 41, p. 36 ; Wisl. p, 29). Most maps err in making the latitudes of
places in the neighbourhood of Santa Fe' too far to the north. The
height of the city of Santa F6 above the level of the sea, according
to Emory, is 6844, according to Wislizenus fully 7046 feet (mean
measurement 6950) ; it therefore resembles that of the Spliigen and
Gotthard passes in the Swiss Alps.

13 The latitude of Albuquerque is taken from the beautiful special
map entitled, Map of the Territory of New Mexico by Kern, 1851.
Its height, according to Emory (p. 166), is 4749 feet; according to Wis-
lizenus (p. 122), 4858.

14 For the latitude of the Paso del Norte compare Wisliz. p. 125
Met. Tables 8—12, Aug. 1846.

TRUE VOLCANOES. 409

Lagos (lat. 21° 20'), 6376 feet, Bt.

Villa de Leon (lat. 21C 7'), 6134 feet, Bfc.

Silao, 5911 feet, Bt.

Guanaxuato (lat. 21° 0' 15"), 6836 feet, Ht.

Salamanca (lat. 20° 40°). 5762 feet, Ht. .

Celaya (lat. 20° 38'), 6017 feet, Ht.

Queretaro (lat. 20° 36' 39"), 6363 feet, Ht.

San Juan del Rio, in the State of Queretaro (lat. 20° SO').
6490 feet, Ht.

Tula (lat. 19° 57'), 6733 feet, Ht.

Pachuca, 8140 feet, lit.

Moran, near Real del Monte, 8511 feet, Ht.

Huehuetoca, at the northern extremity of the great plain
of Mexico (lat. 19° 48'), 7533 feet, Ht.

Mexico (lat. 19° 25' 45"), 7469 feet, Ht.

Toluca (lat. 19° 16'), 8825 feet, Ht.

Venta de Chalco, at the south-eastern extremity of the
great plain of Puebla, 7712 feet, Ht.

San Francisco Ocotlan, at the western extremity of the
great plain of Puebla, 7680 feet, Ht.

Cholula, at the foot of the ancient graduated Pyramid
(lat. 19C 2'), 6906 feet, Ht.

La Puebla de los Angeles (lat. 19° 0' 15"), 7201 feet, Ht.

(The village of las Vigas marks the eastern extremity of
the elevated plain of Anahuac, lat. 19° 37' ; the height of
the village is 7814 feet, Ht).

Thus, though previous to the commencement of the 19th
century not a single altitude had been barometrically taken
in the whole of JS"evv Spain, the hypsometrical and in most
cases also astronomical observations for thirty-two places in
the direction from north to south, in a zone of nearly 16^°
of latitude, between the town of Santa Fe and the capital
of Mexico, have been accomplished. We thus see that the
surface of the wide elevated plain of Mexico assumes an
undulating form varying in the centre from 5850 to 7500
feet in height. The lowest portion of the road from Parras
to Albuquerque is even 1066 feet higher than the highest
point of Vesuvius.

The great, though gentle,15 swelling of the soil, whose

15 Compare Fremont, Report of the Exploring Exped. in 1842, p. 60;
Dana, Geology of the United States Expl. Exped. pp. 611— t>13; aud fof

110 COSMOS.

highest portion we have just surveyed, and which from
south to north, from the tropical part to the parallels
of 42° and 44°, so increases in extent from east to west
that the Great Basin, westward of the great Salt Lake of
the Mormons, has a diameter of upwards of 340 geogra-
phical miles, with a mean elevation of nearly 5800 feet,
differs very considerably from the rampart-like mountain-
chains by which it is surmounted. Our knowledge of this
configuration is one of the chief poinits of Fremont's great
hypsometrical investigations in the years 1842 and 1844.
This swelling of the soil belongs to a different epoch
from that late upheaval which we call mountain-chains
and systems of varied direction. At the point where,
about 32° lat., the mountain-mass of Chihuahua, accord-
ing to the present settlement of the boundaries, enters the
western territory of the United States (in the provinces
taken from Mexico), it begins to bear the not very definite
title of the Sierra Madre. A decided bifurcation,16 however,
occurs in the neighbourhood of Albuquerque, and at this
bifurcation the western chain still maintains the general

South America, Alcide D'Orbigny, Voy. dans I'Amerique merid. Atlas,
pi. viii. de Geologic spfoiale, fig. i.

16 For this bifurcation and the correct denomination of the east
f.nd west chains see the large special map of the Territory of Neiv
Mexico, by Parke and Kern, 1851 : Edwin Johnson's Map of .Railroads,
1854; John Bartlett's Map of the Boundary Commission, 1854 : Ex-
plorations and Surveys from the Mississippi to the Pacific in 1853
and, 1854, vol. i, p. 15; and, above all, the admirable and comprehensive
work of Jules Marcou, Geologist of the Southern Pacific R. R. Survey,
under the command of Lieutenant Whipple, entitled Resume explicatif
dune Carte geologique des Etats Unis et d'un Profil geologique allant de
la vallee du Mississippi, aux cdtes del' Ocean Pacifique, pp. 113 — 116;
also in the Bulletin de la Societe geologique de la France, 2e Se"rie, t. xii,
p. 813. In the elongated valley closed by the Sierra Madre, or Rocky
Mountains, lat. 35° — 38i°, the separate groups of which the western
chain of the Sierra Madre and the eastern chain of the Rocky Moun-
tains (Sierra de Sandia) consist bear different names. To the first chain
belong, reckoning from south to north, the Sierra de las Grullas, the
S. de los Mimbres (Wislizenus, pp. 22 and 54), Mount Taylor (lat. 35°
15'), the S. de Jemez and the S. de San Juan ; in the eastern chain the
Moro Peaks, or Sierra de la Sangre de Cristo, are distinguished from
the Spanish Peaks (lat. 37° 32') and the north westerly tending White
Mountains, which close the elongated valley of Taosand Santa Fe. Pro-
fessor Julius Frobel, whose examination of the volcanoes of Central
America I have already noticed (Cosmos, above, p. 274), has with rnuuh

TRUE VOLCANOES. 411

title of the Sierra Madre, while the eastern branch has re-
ceived from lat. 36° 10' forward (a little to the north of
Santa Fe) from American and English travellers the equally
ill-chosen, but now universally accepted title of the Kocky
Mountains. The two chains form a lengthened valley, in
which Albuquerque, Santa Fe and Taos lie, and through
which the Rio Grande del Norte flows. In lat. 38 1° this
valley is closed by a chain running east and west for the
space of 88 geographical miles, while the rocky mountains
extend undivided in a meridional direction as far as lat. 41°.
In this intermediate space rise somewhat to the east the
Spanish Peaks, Pike's Peak (5800 feet), which has been

ability elucidated the indefinite geographical appellation of Sierra
Madre on the older maps, but he has at the same time, in a treatise
entitled Remarks contributing to the Physical Geography of the North
American Continent (9th Annual Report of the Smithsonian Institution,
1855, pp. 272 — 281), given expression to a conjecture which, after
having examined all the materials within my reach, I am unable to
assent to, namely, that the Rocky Mountains are not to be regarded as
a continuation of the Mexican Mountain range in the tropical zone of
Anahuac. Uninterrupted mountain chains, like those of the Apennines,
the Swiss Jura, the Pyrenees, and a great part of the German Alps,
certainly do not exist from the 19th to the 44th degrees of latitude,
from Popocatepetl in Anahuac as far as to the north of Fremont's Peak
in the Rocky Mountains, in the direction from SS.E. to NN.W., but the
immense swelling of the surface of the land which goes on increasing
in breadth towards the north and north-west, is continuous from
tropical Mexico to Oregon, and on this swelling (or elevated plain),
which is itself the great geognostic phenomenon, separate groups of
mountains, running in often varying directions, rise over fissures which
have been formed more recently and at different periods. These super-
imposed groups of mountains, which, however, in the Rocky Mountains
are for an extent of 8 degrees of latitude connected together almost like
a rampart, and rendered visible to a great distance by conical moun-
tains, chiefly trachytic, from 10,000 to 12,000 feet high, produce an
impression on the uiind of the traveller which is only the more profound
from the circumstance that the elevated plateau which stretches far
and wide around him assumes in his eyes the appearance of a plain of
the level country. Though in reference to the Cordilleras of South
America, a considerable part of which is known to me by personal
inspection, we speak of double and triple ranges (in fact the Spanish
expression las Cordilleras de los Andes refers to such a disposition and
partition of the chain), we must not forget that even here the direc-
tions of the separate ranges of mountain groups, whether in long ridges
or in consecutive domes, are by no means parallel, either to one
mother, or to the direction of the entire swell of tb« land.

412 COSMOS.

beautifully delineated by Fremont, James' Peak (11,434 feet),
and the three Park Mountains, all of which enclose three
deep valleys, the lateral walls of which rise up, along with
the eastern Long's Peak, or Big Horn, to a height of 9060
and 11,191 feet.17 On the eastern boundary, between
Middle and North Park, the mountain chain all at once
changes its direction and runs from lat. 40|-0 to 44° for a
distance of about 260 geographical miles from south-east to
north-west. In this intermediate space lie the south Pass
(7490 feet), and the famous Wind Biver Mountains, so
singularly sharp pointed, together with Fremont's Peak
(lat. 43° 8'), which reaches the height of 13,567 feet. In
the parallel of 44,° in the neighbourhood of the Three
Tetons. where the north-westerly direction ceases, the meri-
dian direction of the Hocky Mountains begins again, and
continues about as far as Lewis and Clarke's Pass, which
lies in lat. 47° 2' and long. 112° 9' 30/' Even at this point,
the chain of the Rocky Mountains maintains a considerable
height (5977 feet), but from the many deep river-beds in
the direction of Flathead River (Clarke's Fork), it soon

tf Frdmont, Explor. Exped. pp. 281 — 288. Pike's Peak, lat. 38° 50',
delineated, at p. 114; Long's Peak, 40° 15'; ascent of Fremont's Peak
(13,570 feet) p. 70. The Wind River Mountains take their name from
the source of a tributary to the Big Horn River, whose waters unite
with those of the Yellow Stone River, which falls into the Upper Mis-
souri (lat. 47° 58', long. 103° 6' 30"). See the delineations of the Alpine
range, rich in mica-slate and granite, pp. 66 and 70. I have in all cases
retained the English names given by the North American Geographers,
as- their translation into a pure German nomenclature has often proved
a rich source of confusion. To help the comparison of the direction
and length of the meridian-chain of the Ural, which, according to the
careful investigations of my friend and travelling companion, Colonel
Ernst Hofmann, takes a curve at the northern extremity towards the
east, and which, from the Truchmenian Mountain Airuk-Tagh (48f °)
to the Sablja Mountains (65°), is fully 1020 geographical miles in length,
with those of the Rocky Mountains, I would here remind the reader
that the latter chain runs, between the parallels of Pike's Peak and
Lewis and Clarke's Pass, from 105° 9' 30" into 112° y' BO" of longitude.
The chain of the Ural which, within the same space of 17 degrees of
latitude, deviates little from the meridian of 59° 0' 30", likewise changes
its direction under the parallel of 65°, and attains, under lat, 67^° the
meridian of 66° 5' 30". Compare Ernst Hofmann, der nordlicke Ural
und das Kustengebirge Pac-Ckoi, 1856, s. 191 and 297—305, with
Humboldt, Asie centrale (1843) t. i. p. 447.

TRUE VOLCANOES. 413

decreases to a more regular level. Clarke's Fork and Lewis
or Snake River unite in forming the great Columbia River,
which will one day prove an important channel for com-
merce. (Explorations for a railroad from tlie Mississippi
River to the Pacific Ocean, made in 1853 — 1854, vol. i, p.
107.)

As in Bolivia, the eastern chain of the Andes furthest
removed from the sea, that of Sorata (21,287 feet) and
Illimani (21,148 feet), furnish no volcano now in a state
of ignition, so also in the western parts of the United
States, the volcanic action on the coast-chain of California
and Oregon is at present very limited. The long chain of
the Rocky Mountains, at a distance from the shores of the
South Sea varying from 480 to 800 geographical miles,
without any trace of still existing volcanic action, neverthe-
less shows, like the eastern chain of Bolivia in the vale of
Yucay,18 on both of its slopes volcanic rock, extinct craters,
and even lavas inclosing obsidian, and beds of scoriae. In
the chain of the Rocky Mountains which we have here
geographically described in accordance with the admirable
observations of Fremont, Emory, Abbot, Wislizenus, Dana,
and Jules Marcou, the latter, a distinguished geologist,
reckons three groups of old volcanic rock on the two slopes.
For the earliest notices of the vulcanicity of this district we
are- also indebted to the investigations made by Fremont
since the years 1842 and 1843 (Report of the Exploring Ex-
pedition to the Rocky Mountains in 1842, and to Oregon and
North California in 1843-44, pp. 164, 184-187, and 193).

On the eastern slope of the Rocky Mountains, on the
south-western road from Bent's Fort, on the Arkansas River
to Santa Fe del Nuevo Mexico, lie two extinct volcanoes, the
Raton Mountains19 with Fisher's Peak, and the hill of El
Cerrito between Galisteo and Pcna Blanca. The lavas of the
former cover the whole district between the Upper Arkansas
and the Canadian River. The Peperino and the volcanic
sconce, which are first met with even in the prairies, on

18 See above p. 295.

19 According to the road-map of 1855, attached to the general repor1;
of the Secretary of State, Jefferson Davis, the Raton Pass rises to an
elevation of as much as 7180 feet above the level of the sea. Compare,
also, Marcou, Resume explicatif d'une Carte GcoL, 1855, p. 113.

414 COSMOS.

approaching the Rocky Mountains from the east, belong
perhaps to old eruptions of the Cerrito, or of the stupendous
Spanish Peaks (37° 32'). This easterly volcanic district of
the isolated Raton Mountains forms an area of 80 geogra-
phical miles in diameter ; its centre lies nearly in latitude
36° 50'.

On the western slope most unmistakeable evidences of
ancient volcanic action are discernible over a wider space,
which has been traversed by the important expedition of
Lieutenant Whipple throughout its whole breadth from
east to west. This variously shaped district, though inter-
rupted for fully 120 geographical miles to the north of the
Sierra de Mogoyon, is comprised (always on the authority
of Marcou's geological chart) between latitude 33° 48' and
35° 40', so that instances of eruption occur further south
than those of the Raton Mountains. Its centre falls nearly
in the parallel of Albuquerque. The area here designated
divides into two sections, that of the crest of the Rocky
Mountains nearer Mount Taylor, which terminates at the
Sierra de Zuni,30 and the western section, called the Sierra
de San Francisco. The conical mountain of Mount Taylor,
12,256 feet high, is surrounded by radiating lava-streams,
which, like Malpays still destitute of all vegetation, covered
over with scoriae and pumice-stone, wind along to a distance
of several miles, precisely as in the district around Hecla.
About 72 geographical miles to the west of the present Pueblo
de Zuni rises the lofty volcanic mountain of San Francisco
itself. It has a peak which has been calculated at more
than 16,000 feet high, and stretches away southward from
the Rio Colorado Chiquito, where, farther to the west, the

20 We must be careful to distinguish, to the west of the mountain-
ridge of Zuni, where the Paso de Zuni attains an elevation of as much
as 7943 feet, between Zuni viejo, the old dilapidated town delineated
by Mollhausen on Whipple's expedition, and the still inhabited Pueblo
de Zuiii. Forty geographical miles north of the latter, near Fort
Defiance, there still exists a very small and isolated volcanic district.
Between the village of Zuni and the descent to the Rio Colorado
chiquito (Little Colorado) lies exposed the petrified forest which
Mollhausen admirably delineated in 1853, and described in a treatise
which he sent to the Geographical Society of Berlin. According to
Marcou (Presume explic. d'une Carte Geol., p. 59), fossil trees and ferna
are mingled with the silicified coniferse.

OF THE

(TY
or

TEUE VOLCA&Om^***** 415

Bill William Mountain, the Aztec Pass (6279 feet), and the
Aquarius Mountains (8526 feet) follow. The volcanic rock
does not terminate at the confluence of the Bill William
Fork with the great Colorado, near the village of the Mohave
Indians (lat. 34°, long. 114°), for, on the other side of the
Rio Colorado at the Soda Lake, several extinct, but still open
craters of eruption, may be recognized.21

Thus we find here in the present New Mexico, in the
volcanic group commencing at the Sierra de San Francisco,
and ending a little to the westward of the Rio Colorado
Grande, or del Occidente (into which the Gila falls), over a
distance of 180 geographical miles, the old volcanic district
of the Auvergne and the Vivarais repeated, and a new and
wide field opened up for geological investigation.

Likewise on the western slope, but 540 geographical miles
more to the north, lies the third ancient volcanic group of
the Rocky Mountains, that of Fremont's Peak, and the two
triple-mountains, whose names, the Trois Te"tons and the
Three Buttes,22 correspond well with their conical forms.
The former lie more to the west than the latter, and con-
sequently farther from the mountain chain. They exhibit
wide-spread, black banks of lava, very much rent, and with
a scorified surface.23

Parallel with the chain of the Rocky Mountains, some-
times single and sometimes double, run several ranges in
which their northern portion from lat. 46° 12', are still the
seat of volcanic action. First, from San Diego to Monterey
(32^° to 36f°), there is the coast-range, specially so-called, a
continuation of the ridge of land on the peninsula of Old, or
Lower, California ; then, for the most part 80 geographical

21 All on the authority of the profiles of Marcou and the above-cited
road-map of 1855.

" The French appellations, introduced by the Canadian fur-hunters,
are generally used in the country and on English maps. According to
the most recent calculations, the relative positions of the extinct vol-
canoes are as follows :— Fremont's Peak, lat. 43° 5', long. 110° 9' 30";
Trois Tenons, lat. 43° 38', long. 110° 49' 30"; Three Buttes, lat. 43° 20',
long. 112° 41' 30"; Fort Hall, lat. 43° 0', long. 111° 24' 30".

-3 Lieut. Mullan, on Volcanic Formation, in the Reports of Explor.
and Surveys, vol. i (1855), pp. 330 and 348; see also Lambert's and
Tinkham's Reports on the Three Buttes, ibid. pp. 167 and 226—230
and Jules Marcou, p. 115,

413 COSMOS.

miles distant from the shore of the South Sea, the Sierra
Nevada (de Alta California) from 36° to 40f° ; then again,
commencing from the lofty Shasty Mountains in the parallel
of Trinidad Bay (lat. 41° 10'), the Cascade range, which
contains the highest still ignited peak, and which, at a
distance of 104 miles from the coast, extends from south to
north far beyond the parallel of the Fuca Strait. Similar in
their course to this latter chain (lat. 43°— 46°), but 280
miles distant from the shore, are the Blue Mountains,24 which
rise in their centre to a height of from 7000 to 8000 feet.
In the central portion of Old California, a little farther to
the north, near the eastern coast or bay in the neighbour-
hood of the former Mission of San Ignacio, in about 28°
north latitude, stands the extinct volcano, known as the
" Volcanes de las Virgenes," which I have given on my chart
of Mexico. This volcano had its last eruption in 1746; but
we possess no reliable information either regarding it or any
of the surrounding districts ; (See Venegas, Noticia de la
California, 1757, t. i, p. 27 ; and Duflot de Moras, Exploration
de I' Oregon et de la Calif ornie, 1844, t. i, pp. 218 and 239).
Ancient volcanic rock has already been found in the coast-
range near the harbour of San Francisco, in the Monte del
Diablo, which Dr. Trask investigated (3673 feet), and in the
auriferous elongated valley of the Rio del Sacramento in a
trachytic crater now fallen in, called the Sacramento Butt,
which Dana has delineated. Farther to the north, the '
Shasty, or Tshashtl Mountains, contain basaltic lavas, obsi-
dian, of which the natives make arrow-heads, and the talc-
like serpentine which makes its appearance on many points
of the earth's surface, and appears to be closely allied to the
volcanic formations. But the true seat of the still existing
igneous action is the Cascade Mountain range, in which,
covered with eternal snow, several of the peaks rise to the
height of 16,000 feet. I shall here give a list of these, pro-
ceeding from south to north. The now ignited, and more or
less active volcanoes, will be (on the plan heretofore adopted)

-4 Dana, p. 616—620 ; Blue Mountains, p. 649—651 ; Sacramento
Butt, p. 630—643; Shasty Mountains, p. 614; Cascade range. On the
Monte Diablo range, perforated by volcanic rock, see also John Trask,
on the Geology of the Coast Mountains and the Sierra Nevada, 1854,
pp. 13—18.

TRUE VOLCANOES. 417

(see above, p. 61, note 71) distinguished by a star. The high
conical mountains not so distinguished, are probably partly
extinct volcanoes, and partly unopened trachytic domes.

Mount Pitt, or M'Laughlin ; lat. 4&° 30', a little to the
west of Lake Tlamat ; height 9548 feet.

Mount Jefferson, or Vancouver (lat. 44° 35'), a conical
mountain.

Mount Hood (lat. 45° 10'), decidedly an extinct volcano,
covered with cellular lava. According to Dana this moun-
tain, as well as Mount St. Helen's, which lies more
northerly in the volcano range, is between 15.000 and
16,000 feet high, though somewhat lower25 than the latter.
Mount Hood was ascended in August, 1853, by Lake, Tra-
vaillot, and Heller.

Mount Swalahos, or Saddle Hill, S.S.E. of Astoria38,
with a fallen in, extinct crater.

Mount St. Helen's,* north of the Columbia river
(lat. 46° 12'). According to Dana, not less than 15,000
feet high27. Still burning and always smoking from the
summit-crater. A volcano of very beautiful, regular, co-
nical form and covered with perpetual snow. There was a
great eruption on the 23rd November, 1842 ; which, ac-
cording to Fremont, covered everything-to a great distance
round with ashes and pumice.

Mount Adams (lat. 46° 18'), almost exactly east of the
volcano of St. Helen's, more than 112 geographical miles
distant from the coast, if it be true that the last-named
and still active mountain, is only 76 of those miles inland.

25 Dana (pp. 615 and 640) estimated the rolcano of St. Helen's at
16,000 feet, and Mount Hood of course under that height, while
according to others Mount Hood is said to attain the great height of
18,316 feet, which is 2521 feet higher than the summit of Mont Blanc,
and 4730 feet higher than Fremont's Peak in the Rocky Mountains.
According to this estimate, (Langrebe, Naturgesckichte der Vulkane,
Bd. i, s. 497), Mount Hood would be only 571 feet- lower than the
volcano Cotopaxi ; on the other hand Mount Hood, according to
Dana, exceeds the highest summit of the Rocky Mountains by 2586
feet at the utmost. I am always desirous of drawing attention to
variantes lectiones such as these.

36 Dana, Geol. o) the U.S. Expl. Exped., pp. 640 and 643—645.

* Variously estimated previously at 10,178 feet by Wilkes, and 13,535
leet by Simpson.

VOL. V. 2 E

418 COSMOS.

Mount Regnier,* also written Mount Rainier (lat.
46° 48') E.S.E. of Fort Nisqually, on Puget's Sound, which
is connected with the Fuca Strait. A burning volcano ;
according to Edwin Johnson's road-map of 1854, 12,330
feet high. It experienced severe eruptions in 1841 and!843.

Mount Olympus (lat. 47° 50'). Only 24 geographical
miles south of the strait of San Juan de Fuca, long so
famous in the history of the South Sea discoveries.

Mount Baker,* a large and still active volcano, situated
in the territory of Washington (lat. 48° 48'), of great
(unmeasured ?) height (not yet determined), and regular
conical form.

Mount Brown (16,000 feet?) and, a little more to the
east, Mount Hooker (16,750 feet ?), are cited by Johnson
as lofty, old-volcanic trachytic mountains, under lat. 52£°,
and long. 117° 40' and 119° 40'. They are therefore re-
markable as being more than 300 geographical miles
distant from the coast.

Mount Edgecombe,* on the small Lazarus Island, near
Sitka (lat. 57° 3'). Its violent igneous eruption in 1796,
has already been mentioned by me (see above, p. 269).
Captain Lisiansky, who ascended it in the first years of
the present century, found the volcano then unignited.
Its height28 reaches, according to Ernst Hofmann, 3039
feet, according to Lisiansky, 2801 feet. Near it are hot
springs which issue from granite, as on the road from the
Valles de Aragua to Portocabello.

Mount Fairweather, or Cerro de Buen Tiempo ; accord-
ing to Malaspina, 4489 metres, or 14,710 feet high29. In
lat. 58G 45'. Covered with pumice-stone, and probably
ignited up to a short time back, like Mount Elias.

The volcano of Cook's Inlet (lat. 60° 8'). According
to Admiral Wrangel 12,065 feet high, and considered by
that intelligent mariner, as well as by Vancouver, to be
an active volcano30.

23 Karsten's Arcldv. fur Mineralogie, Bd. i, 1829, s. 243.

29 Humboldt, Lssai Polit. sur la Nouv. Esp., t. i, p. 266. torn, ii, p. 310.

30 According to a manuscript which I was permitted to examine in
the year 1803, in the Archives of Mexico, the whole coast of Nutka,
as far as what was afterwards called " Cook's Inlet," was visited during
the expedition of Juan Perez, and Estevan Jose" Martinez, in the year
1774.

TRUE VOLCANOES. 419

Mount Elias, lat. 60° 17' ; long. 136° 10 30". Accord-
ing to Malaspina's manuscripts, which I found in the
Archives of Mexico, 5441 metres, or 17,854 feet. Ac-
cording to Captain Denham's chart, from 1853 to 1856,
the height is only 14,970 feet.

What M'Clure, in his account of the North- West Passage,
calls the Volcano of Franklin's Bay (lat. 69° 57' ; long 127°)
eastward of the mouth of the Mackenzie river, seems to be
a kind of earth-fire., or salses, throwing out hot, sulphurous
vapours. An eye-witness, the Missionary Miertsching, in-
terpreter to the expedition on board the ship "Investigator,"
found from thirty to forty columns of smoke rising from
fissures in the earth, or from small conical mounds of clays
of various colours. The sulphurous odour was so strong
that it was scarcely possible to approach the columns of
smoke within a distance of twelve paces. No rock or
other solid masses could be discovered in the immediate
vicinity. Lights were seen from the ship at night, no ejec-
tions of mud, but great heat of the bed of the sea, and
small pools of water containing sulphuric acid were observed.
The district merits a careful investigation, and the pheno-
menon stands quite unconnected there, like the volcanic
action of the Cerro de Buen Tiempo, or of Mount Elias in
the Californian Cascade range (M'Clure, Discovery of the
N. W. Passage, p. 99 ; Papers relative to the Arctic Ex-
pedition, 1854, p. 34; Miertsching's Reise-Tagebuch ;
Gnadau, 1855, s. 46).

1 have hitherto treated the volcanic vital activities of our
planet in their intimate connections, as if forming an ascending
scale of the great and mysterious phenomenon of a reaction
of its fused interior upon its surface, clothed with animal and
vegetable organisms. I have considered next in order to the
almost purely dynamic effects of the earthquake (the wave
of concussion) the thermal springs and salses, that is to say,
phenomena produced, with or without spontaneous ignition,
by the permanent elevation of temperature communicated to
the water-springs and streams of gas, as well as by diversity
of chemical mixture. The highest, and in its expressions,
the most complicated grade of the scale, is presented by the
volcanoes, which call into action the great and varied pro-
cesses of crystalline rock-formation by the dry method, and

2 E 2

120 COSMOS.

which consequently do not simply reduce and destroy, but
appear in the character of creative powers, and form the
materials for new combinations. A considerable portion -of
very recent, if not of the most recent, mountain-strata, is the
work of volcanic action, whether effected, as in the present
day, by the pouring forth of molten masses at many points
of the earth from peculiar conical, or dome-shaped elevated
stages, or, as in the early years of our planet's existence,
by the immediate issuing forth of basaltic and trachytic rock
by the side of the sedimentary strata, from a net-work of open
fissures, without the intervention of any such structures.

In the preceding pages I have most carefully endeavoured
to determine the locality of the points at which a commu-
nication has long continued open between the fluid interior
of the earth and the atmosphere. It now remains to sum
up the number of these points, to separate out of the rich
abundance of the volcanoes which have been active in very
remote historical periods, those which are still ignited at the
present day, and to consider these according to their division
into Continental and Insular Volcanoes. If all those which,
in this enumeration, I think I may venture to consider the
lowest limit of the number, were simultaneously in action,
their influence on the condition of the atmosphere, and its
climatic, and especially its electric relations, would certainly
be extremely perceptible ; but as the eruptions do not take
place simultaneously, but at different times, their effect is
diminished and is confined within very narrow and chiefly
mere local limits. In great eruptions there occur around the
crater, as a consequence of the exhalation, volcanic storms,
which being accompanied by lightning and torrents of rain,
often occasion great ravages ; but these atmospheric pheno-
mena have no generally extended results. For that the re-
markable obscurity (known by the name o ithe dry fog)
which for the space of several months, from May to August
of the year 1783, overspread a very considerable part of
Europe and A sia, as well as the North of Africa — while the
sky was seen pure and untroubled at the top oi the lofty
mountains of Switzerland — could have been occasioned by the
unusual activity of the Icelandic volcanicity, and the earth-
quakes of Calabria, as is even now sometimes maintained,
seems to me very improbable on account of the magnitude of

TRUE VOLCANOES. 421

the effect produced.* Yet a certain apparent influence of
earthquakes, in cases where they occupy much space in
changing the commencement of the rainy season, as in the
highland of Quito and Riobamba (in February, 1797), or in
the south-eastern countries of Europe and Asia Minor (in the
Autumn of 1856), might indeed be viewed as the isolated
influence of a volcanic eruption.

In the following table the first figures denote the number
of the volcanoes cited in the preceding pages, while the second
figures, inclosed in parentheses, denote the number of those
which in recent times have given evidence of their igneous
activity.

Number of Volcanoes on the Earth.
I Europe (above, p. 349, 350) ... ... ... 7 (4)

II Islands of the Atlantic Ocean (p. 351—354) ... 14 (8)

III Africa (p. 354, 355) ... 3 (1)

IV Asia— Continental 25 (15)

(1) Western and Central (p. 356—362) ... 11 (6)

(2) The Peninsula of Kamtschatka (p. 362—367) 14 (9)
V Eastern Asiatic Islands (p. 367—377) ... .. 69 (54)

VI South Asiatic Islands (p. 297— 308, 377— 382) ... 120 (56)
VII Indian Ocean (p. 382—388, and note 79 at p. 385, 386) 9 (5)
VIII South Sea (p. 388—401, notes 83—85 at p. 389—391) 40 (26j

IX America— Continental 115 (53)

(1) South America 56 (26)

(a) Chili (p. 285, note 75 at p. 287— 290) ... 24 (13)

(b) Peru and Bolivia (p. 285—291, note 74 at

p. 286, 287) 14 (3)

(c) Quito and New Granada (p. 285, note 73

at p. 286) 18 (10)

(2) Central America (p. 258, 268—279, 285, 328,

notes 66—68 at p. 271—278) 29 (18)

(3) Mexico, south of the Rio Gila (p. 279, 281,

285, 308—328, and notes 6—13 at p. 310—

322, 401—429, notes 7—14 at p. 402—408) 6 (4)

(4) North- Western America, north of the Gila

(p. 409—419) 24 (5)

The Antilles^1 5 (3)

Total 407 (225)

* [A similar fog overspread the Tyrol and Switzerland in 1755, just
before the great earthquake which destroyed Lisbon. It appeared to
be composed of earthy particles reduced to an extreme degree of fine-
ness.]— TR.

31 In the Antilles the volcanic activity is confined to what are
called the " Little Antilles," three or four still active volcanoes having

422 COSMOS.

The result of this laborious work, on which I have long

broken out on a somewhat curvilinear fissure running from South to
north, nearly parallel to the volcanic fissure of Central America. In
the course of the considerations induced by the simultaueousness of
the earthquakes in the valleys of the rivers Ohio, Mississippi, and Ar-
kansa,s, with those of the Orinoco, and of the shore of Venezuela, I have
already described the little sea of the Antilles, in its connection with
the Gulf of Mexico and the great plain of Louisiana, between the Alle-
ghanys and the Rocky Mountains, on geognostic views, as a single
ancient basin {Voyage aux Regions Eqmnoxiales, t. ii, pp. 5 and 19; see
also above, p. 6). This basin is intersected in its centre, between 18°
and 22° lat. by a plutonic mountain-range from Cape Catoche of the
peninsula of Yucatan to Tortola and Virgen gorda. Cuba, Haiti, and
Porto Rico, form a range running from west to east, parallel with
the granite and gneiss chain of Caraccas. On the other hand, the Little
Antilles, which are for the most part volcanic, unite together the plu-
tonic chain just alluded to (that of the Great Antilles) and that of
the shore of Venezuela, closing the southern portion of the basin on the
east. The still active volcanoes of the Little Antilles lie between the
parallels of 13° to 16£°, in the following order, reckoning from south
to north : —

The volcano of the island of St. Vincent, stated sometimes at 3197
and sometimes at 5052 feet high. Since the eruption of 1718 all re-
mained quiet, until an immense ejection of lava took place on the 27th
April, 1812. The first commotions commenced as early as May, 1811,
near the Crater, three months after the island of Sabrina in the
Azores had risen from the sea. They began faintly in the mountain-
valley of Caraccas, 3496 feet above the surface of the sea, in December
of the same year. The complete destruction of the great city took
place on the 26th March, 1812. As the earthquake which destroyed
Cumana pn the 14th December, 1796, was with justice ascribed to the
eruption of the volcano of Guadaloupe (the end of September, 17S6),
in like manner the destruction of Caraccas appears to have been the effect
of the reaction of asoutherly volcano of the Antilles, — that of St. Vincent.
The frightful subterranean noise, like the thundering of cannon, pro-
duced by a violent eruption of the latter volcano on the 30th April,
1812, was heard on the distant grass-plains (Llanos) of Calabozo, and
on the shores of the Rio Apure, 192 geographical miles farther to the
west than its junction with the Orinoco (Humboldt, Voy. t. ii, p. 14).
The volcano of St. Vincent had thrown out no lava since 1718, but on
the 30th April, a stream of lava flowed from the summit crater, and in
four hours reached the sea shore. It was a very striking circumstance,
and one which has been confirmed to me by very intelligent coasting
mariners, that the noise was very much stronger on the open sea, far
from the island, than near the shore.

The volcano of the island S. Lucia, commonly called only a solfa-
tara, is scarcely 1200 to 1800 feet high. In the crater are several small
basins periodically filled with boiling water. In the year 1766, an
ejection of scorise and cinders is said to have been observed, which if

TRUE VOLCANOES. 423

been occnpied, having in all cases consulted the original

certainly an unusual phenomenon in a solfatara, for although the
careful investigations of James Forbes and Poulett Scrope, leave no
room to doubt that an eruption took place from the Solfatara of Poz-
zuoli in the year 1198, yet one might be inclined to consider that event
as a collateral effect produced by the great neighbouring volcano, Vesu
vius (See Forbes in the Edinb. Journal of Science, vol. i, p. 128, and
Poulett Scrope in the Transact, of the Geol. Soc. 2nd Ser. vol. ii, p. 346).
Lancerote, Hawaii and the Sunda Islands furnish us with analogous
examples of eruptions at exceedingly great distances from the summit
craters, the peculiar seat of action. It is true the solfataraof Pozzuoli was
not disturbed on the occasion of great eruptions of Vesuvius in the
years 1794, 1822, 1850 and 1855, (Julius Schmidt, Ueber die Eruption des
Vesuvs. in Mai, 1855, p. 156), though Strabo (lib. v, p. 245), long before
the eruption of Vesuvius, speaks of fire, somewhat vaguely it is true, in
the scorched plains of Dicaarchia, near Curncea and Phlegra. Dicaarchia
in Hannibal's time received the name of Puteoli from the Romans who
colonised it. " Some are of opinion," continues Strabo, " on account of
the bad smell of the water that the whole of that district as far as
Baise and Cumoea is so called, because it is full of sulphur, fire and
warm water. Some think that on this account Cumoea (Cumanus ager)
is called also Phlegra . . . ." and then again Strabo mentions discharges
of fire and water, " irpo\oaQ TOV TTVOOQ Kai TOV r^'arog)."

The recent volcanic action of the island of Martinique in the Mon-
tagne Pelee (according to Dupuget, 4706 feet high), the Vauclin and the
Pitons du Carbet is still more doubtful. The great eruption of vapour
on the 22nd January, 1792, described by Chisholm, and the shower of
ashes of the 5th August, 1851, deserve to be more thoroughly inquired
into.

The Soufriere de la Guadeloupe, accoi'ding to the older measure-
ments of Amic and Le Boucher, 5435 and 5109 feet high, but accord-
ing to the latest and very correct calculations of Charles Sainte-Claire
Deville, only 4867 feet high, exhibited itself on the 28th September,
1797, 78 days before the great earthquake and the destruction of the
town of Cumana, as a volcano ejecting pumice (Rapport fait au Ge'ne'ral
Victor Hugues par Amic et Hapel sur le Volcan de la Basse Terre,
dans la nuit du 7 au 8 Vendimiaire, an 6, pag. 46; Humboldt, Voyage,
t. i, p. 316). The lower part of the mountain is dioritic rock, the vol-
canic cone, the summit of which is open, is trachyte, containing labra-
dorite. Lava does not appear even to have flowed in streams from the
mountain called on account of its usual condition, the Soufriere, either
from the summit crater, or from the lateral fissures, but the ashes of
the eruptions of Sept. 1797, Dec. 1836, and Feb. 1837, examined by
the excellent and much lamented Dufrenoy, with his peculiar accuracy,
were found to be finely pulverised fragments of lava, in which fel-
spathic minerals (labradorite, rhyakolite and sanidine) were recognisable
together with pyroxene. (See Lherminier, Daver, Elie de Beaumont
and Dufrenoy, in the Comptes rend us de V Acad. des Sc. t. iv, 1837,
pp. 294; 651 and 743—749). Small fragments of quartz have also

424 COSMOS.

sources of information (the geological and geographical

been recognised by Deville in the trachytes of the soufriere, together
with the crystals of labradorite (Comptes rendus, t. xxxii, p. 675), while
Gustav Rose even iound hexagonal-dodecahfidra of quartz in the tra-
chytes of the volcano of Arequipa (Meyen, Reise um dieErde, Bd. ii, s. 23).
The phenomena here described, of the temporary ejection of very
various mineral productions from the fissure-openings of a sou-
friere, remind us very forcibly that what we are accustomed to deno-
minate a solfatara, soufriere or fumarole, denotes properly speaking
only certain conditions of volcanic action. Volcanoes which have once
emitted lava ; or, when that failed, have ejected loose scoriae of con-
siderable volume, or finally the same scoriae pulverised by trituration,
pass on a diminution of their activity, into a state in which they
yield only sulphur sublimates of sulphurous acid and aqueous vapour.
If as such we were to call them semi- volcanoes, it would readily convey
the idea that they are a peculiar class of volcanoes. Bunsen, to whom
along with Boussingault, Senarmont, Charles Deville and Danbree
science is indebted for such important advances for their ingenious
and happy application of chemistry to geology, and especially to the
volcanic processes, shows " how, when in sulphur sublimations,
which almost always accompany volcanic eruptions, the masses of sul-
phur in the form of vapour come in contact with the glowing pyroxene
rocks, the sulphurous a^id is generated by the partial decomposition of
the oxyde of iron contained in those rocks. If the volcanic action then
sinks to a lower temperature, the chemical action of that zone then
enters into a new phase. The sulphurous combinations of iron and
perhaps of metals of the earths and alkalies there produced, commence
their operation on the aqueous vapour, and the result of the alternate
action is the generation of sulphuretted hydrogen and the products of
its decomposition, disengaged hydrogen and sulphur vapour." — The
sulphur fumaroles outlive the great volcanic eruptions for centuries.
The muriatic acid fumaroles belong to a different and later period.
They seldom assume the character of permanent phenomena. The
muriatic acid in the gases of craters is generated in this way ; the
common salt which so often occurs as a product of sublimation in vol-
canoes, particularly in Vesuvius, is decomposed in higher temperatures,
itnder the co-operation of aqueous vapour and silicates, and forms
muriatic acid and soda, the latter combining with the silicates pre-
sent. Muriatic acid fumaroles which, in Italian volcanoes, are not un-
frequently on the most extensive scale, and are then generally accom-
panied by immense sublimations of common salt, seem to be of a very
unimportant character in Iceland. The concluding stages in the chro-
nological series of all these phenomena consist in mere emanations of
carbonic acid. The hydrogen contained in the volcanic gases has
hitherto been almost entirely overlooked. It is present in the vapour,
springs of the great solfataras of Krisuvik and Reykjalidh in Iceland,
and is indeed at both those places combined with sulphuretted hydro-
gen. When the latter corne in contact with sulphuric acid, they are
both mutually decomposed by the separation of the sulphur, so that

TRUE VOLCANOES. 425

accounts of travels), is that, out of 407 volcanoes cited by

they can never occur together. They are however not unfrequently
met with on one and the same field of fumaroles in close proximity to
each other. Unrecognisable as was the sulphuretted hydrogen gas in
the Icelandic solfataras just mentioned, it failed on the other hand en-
tirely in the solfataric condition assumed by the crater of Hecla shortly
after the eruption of the year 1845, — that is to say, in the first phase
of the volcanic secondary action. Not the smallest trace of sulphuretted
Hydrogen could be detected, either by the smell or by re-agents, while
che copious sublimation of sulphur, the smell of which extended to a
great distance, afforded indisputable evidence of the presence of sul-
phurous acid. In fact, on the approach of a lighted cigar to one of these
fumaroles those thick clouds of smoke were produced which Melloni
and Piria have noticed as a test of the smallest trace of sulphuretted
hydrogen (Comptes rendus, t. xi, 1840, p. 352, and Poggendorff's Anna-
len, Erganzungsband, 1842, s. 511). As it may however be easily
seen by experiment that even sulphur itself, when sublimated with
aqueous vapour, produces the same phenomenon, it remains doubtful
whether any trace whatever of sulphuretted hydrogen accompanied
the emanations from the crater of Hecla in 1845, and of Vesuvius in
1843 (compare Robert Bunsen's admirable and geologically important
treatise on the processes of formation of the volcanic rock of Iceland,
in Poggend. Annal. Bd. Ixxxiii, 1851. s. 241, 244, 246, 248, 254
and 256 ; serving as an extension and rectification of the treatises
of 1847 in Wohler's and Liebig's Annalen der Chemie und Phar-
macie. Bd. Ixii, s. 19). That the emanations from the solfatara of
Pozzuoli are not sulphuretted hydrogen, and that no sulphur is
deposited from them by contact with the atmosphere, as Breislak has
conjectured (Essai Mineralogique sur la Soufri&re de Pozzuoli,
1792, p. 128—130), was remarked by Gay-Lussac when I visited the
Phlegrsean Fields with him at the time of the great eruption of lava in
the year 1805. That acute observer, Archangelo Scacchi likewise de-
cidedly denies the existence of sulphuretted hydrogen (Memorie geo-
logiche suUa Campania, 1849, p. 49 — 121), Piria's test seeming to him
only to prove the presence of aqueous vapour ; — '• Son di avviso che lo
solfo emane mescolato a i vapori acquei senza esserein chimica combi-
nazione con altre sostanze," — " I am of opinion that the sulphur ema-
nates mixed with aqueous vapours without being in combination with
other substances." An actual analysis, however, long looked for by me,
of the gases ejected by the solfatara of Pozzuoli. has been very recently
published by Charles Sainte-Claire Deville and Leblanc, and has com-
pletely established the absence of sulphuretted hydrogen (Comptes
rendus de I'Acad. d. Sc. t. xliii, 1856, p. 746). Sartorius von Waltershau-
sen, on the other hand, observed on cones of eruption of Etna, in 1811,
a strong smell of sulphuretted hydrogen, where in other years sulphu-
rous acid only was perceived. Nor did Charles Deville discover any sul-
phuretted hydrogen at Girgenti, or in the Macalube, but a small por-
tion of it on the eastern declivity of Etna, in the spring of Santa
Veneriiia. It is remarkable, that throughout the important series o/

426 COSMOS.

me, 225 have exhibited proofs of activity in modern times.
Previous statements of the number32 of active volcanoes
have given sometimes about 30 and sometimes about 50
less, because they were prepared on different principles.
In the division made by me. I have confined myself to those
volcanoes which still emit vapours, or which have had
historically certain eruptions in the 19th or in the latter
half of the 18th century. There are doubtless instances
of the intermission of eruptions which extend over four
centuries and more, but these phenomena are of very rare
occurrence. We are acquainted with the lengthened series
of the eruptions of Vesuvius in the years 79, 203, 512, 652,
983, 1138, and 1500. Previous to the great eruption of
Epomeo on Ischia in the year 1302, we are acquainted only
with those which occurred in the 36th and 45th years before
our era, that is to say, 55 years before the eruption of
Vesuvius.

Strabo, who died at the age of 90 under Tiberius (99 years
after the occupation of Vesuvius by Spartacus), and whom
no historical account of any former eruption had ever reached,
describes Vesuvius notwithstanding as an ancient and long
extinct volcano. " Above the places " (Herculaneum and
Pompeii), he says, "lies the Mount Vesuios, covered round
by the most beautiful farms, except on the summit. This is
indeed for the most part pretty smooth, but on the whole
chemical analyses made by Boussingault on gas-exhaling volcanoes of
the Andes (from Purace' and Tolima to the elevated plains of las Pastes
and Quito), both muriatic acid and sulphuretted hydrogen (hydrogene
sulf ureux) are wanting.

32 The following numbers are given in older works as those of the
volcanoes still in a state of activity : — by Werner, 193 ; by Caesar von
Leonhard, 187; by Arago, 175 (Astronomic Populaire, t. iii, p. 170);
variations which, as compared with my results, all show a difference
ranging from £ to TV in a downward direction, occasioned partly by
diversity of principle in judging of the igneous state of a volcano, and
partly by a deficiency of materials for forming a correct judgment. It
is well known, as I have previously remarked, and as we learn from
historical experience, that volcanoes which have been held to be extinct
have, after the lapse of very long periods, again become active, and
therefore the result, which I have obtained must be considered as
rather too low than too high. Leopold von Buch, in the supplement
to his masterly description of the Canary Isles, and Landgrebe, in
his Geography of Volcanoes, have not attempted to give any general
numerical result^

TRUE VOLCANOES. 427

unfruitful, and having an ashy appearance. It exhibits
fissured hollows of red-coloured rock, as if it were corroded
by fire, so that it might be supposed that this place had
formerly burned and had gulphs of fire, which, however, had
died away when the fuel became consumed." (Strabo, lib. v.
page 247, Casaub.) This description of the primitive form
of Vesuvius indicates neither a cone of cinders nor a crater-
like hollowing33 of the ancient summit, such as, being walled
in, could have served Spartacus34 and his gladiators for a
defensive stronghold.

33 This description is therefore totally at variance with the often
repeated representation of Vesuvius, according to Strabo, given in
Poggendorffs Annalen der Physik, Bd. xxxvii, s. 190, Tafel 1. It
is a very late writer, Dio Cassius, under Septimius Severus, who
first speaks, not (as is frequently supposed) of the production of
several summits, but of the changes of form which the summits
have undergone in the course of time. He records (quite in con-
firmation of Strabo) that the mountain formerly had everywhere a
flat summit. His words are as follows (lib. Ixvi, cap. 21, ed. Sturz,
vol. iv, 1824, p. 240): — "For Vesuvius is situated by the sea near
Naples, and has numerous sources of fire. The whole mountain was
formerly of uniform height, and the fire arose from its centre, for at
this part only is it in a state of combustion. Outwardly, however, the
whole of it is still down to our times devoid of fire. But, while the
exterior is always without conflagration, and the centre is dried up
(heated) and converted into cinders, the peaks round about it have still
their ancient height. But the whole of the igneous part, being con-
sumed by length of time, has become hollow by sinking in, so that the
whole mountain (if we may compare a small thing with a great)
resembles an amphitheatre." (Comp. Sturz, vol. vi, Annot, ii, p. 568).
This is a clear description of those mountain-masses which, since the
year 79, have formed the margins of the crater. The explanation of
this passage, by referring it to the Atrio del Cavallo, appears to me
erroneous. According to the large and excellent hypsometrical work
of that distinguished Olmutz astronomer, Julius Schmidt, for the year
1855, the Punta Nasone of the Somma is 3771 feet, the Atrio del
Cavallo, at the foot of the Punta Nasone, 2661, and the Punta or
Rocca del Palo (the highest edge of the crater of Vesuvius to the
north, pp. 112—116; 3992 feet high. My barometrical measurements
of 1822 (Views of Nature, pp. 376—377) gave for the same three points
3747 feet, 2577 feet, and 4022 feet— showing a difference of 24, 84, and
30 feet respectively. The floor of the Atrio del Cavallo has, according
to Julius Schmidt (Eruption des Vesuvs im Mai 1855, p. 95), undergone
great alterations of level since the eruption of Feb. 1850.

14 Velleius Paterculus, who died under Tiberius, mentions Vesuvius,
it is true, as the mountain which Spartacus occupied with his gladiators
(ii. 30), while Plutarch, in his Biography of Crassus, cap. ii, speaks only

428 COSMOS.

Diodorus Siculus, likewise (lib. iv. cap. 21, 5), who lived
tinder Caesar and Augustus, in his account of the progress of
-Hercules and his battles with the giants in the Phlegreean
Fields, describes " what is now called Vesuvius as a Xo'0os,
which, like Etna in Sicily, once emitted a great deal of fire,
and (still) shows traces of its former ignition." He calls the
whole space between Cumse and Naples the Phlegrsean Fields,
as Polybius does the still greater space between Capua and
Nola (lib. ii, cap. 17), while Strabo (lib. v, page 246) describes
with much local truth the neighbourhood of Puteoli (Dic«-
archia), where the great Solfatara lies, and calls it ' Upaiarov
(i ryopd. In later times the name of TO, (pXe^oam TreSi'a is
ordinarily confined to this district, as at this day geologists
place the mineralogical composition of the lavas of the
Phlegrsean Fields in opposition to those from the neighbour-
hood of Vesuvius. The same opinion that in ancient times
there was fire burning within Vesuvius, and that that
mountain had formerly had eruptions, is most distinctly
expressed in the architectural work of Vitruvius (lib. ii,
cap. 6), in a passage which has hitherto not been sufficiently
regarded : — " Non minus etiam memoratur, antiquitus crevisse
ardores et abundavisse sub Vesuvio monte, et inde evomuisse
circa agros flammam. Ideoque nunc qui spongia sive pumex
Pompejanus vocatur, excoctus ex alio genere lapidis, in hanc
redactus esse videtur generis qualitatem. Id autem genus
spongise, quod inde eximitur, non in omnibus locis nascitur,
nisi circurn ^Etnam, et collibus Mysise, qui a Graecis /caTa/ee-
Kavuevoi nominantur." It is also related that in ancient
times the fire increased and abounded beneath Mount
Vesuvius, and vomited out flame from thence on the fields
around. So that now what is called spongia, or Pompeian
pumex, baked out of some other kind of stone, seems to have
been reduced to this kind of substance. But that kind of
spongia which is got out of there is not produced in all
of a rocky district, having a single narrow entrance. The servile war
of Spartacus took place in the 681st year of Rome, or 152 years before the
eruption of Vesuvius described by Pliny (24th August, 79, A.D.). The
circumstance that Floras, a writer who lived in the time of Trajan, and
who, being acquainted with the eruption just referred to, knew what
was hidden in the interior of the mountain, calls it "cavus," proves
nothing, as others have already observed, for its earlier configuration
(Florus, lib. i, cap. 16, "Vesuvius mons, ^Etnsei ignis imitator;" lib. iii,
cap. 20,-" fauces cavi mentis)."

TRUE VOLCANOES. 429

places, only around ^Etna and on the hills of Mysia, which
are called by the Greeks KaraKeKavpevoi.) Now, it can no
longer be doubted, since the investigations of Bockh and
Hirt, that Vitruvius lived in the time of Augustus,36 and
consequently a full century before the eruption of Vesuvius,
at which the elder Pliny met his death. The passage thus
quoted, therefore, and the expression pumex Pompeianus
(thus connecting pumice-stone with Pompeii), present a
special geological interest in relation to the question raised
as to whether, according to the acute conjecture of Leopold
von Buch,36 Pompeii was overwhelmed only by the pumiceous
tufa-beds thrown up on the first formation of Mount Somma;
these beds, which are of submarine formation, covering in
horizontal layers the whole level between the Apennine
range and the west coast of Capua as far as Sorento, and
from Nola to the other side of Naples, — or whether Vesuvius
itself, entirely contrary to its present habit, ejected the
pumice from its interior.

Both Carmine Lippi,37 who (1816) describes the tufa
covering of Pompeii as an aqueous deposit, and his ingenious
opponent Archangelo Scacchi,38 in the letter addressed to the
Cavaliere Francesco Avellino (1843), have directed attention
to the remarkable phenomenon that a portion of the pumice
of Pompeii and Mount Somma contains small fragments
of chalk which have not lost their carbonic acid, a circum-
stance which, on the supposition that they have been exposed
to a great pressure during their igneous formation, can
excite but little surprise. I have myself had the opportunity

35 At all events Vitruvius wrote earlier than the elder Pliny, as is
evident, not merely because he is three separate times cited by Pliny
in his list of authorities, so unjustly attacked by the English translator
Newton (lib. xvi, xxxv, and xxxvi), but because in book xxxv, cap. 14,
s. 170 — 172, as has been distinctly proved by Sillig (vol. v, 1851,
p. 277) and Brunn (Diss. de auctorum indicibus Plinianis, Bonnae, 1856,
pp. 55 — 60), a passage has actually been extracted from Vitruvius by
Pliny himself. See also Sillig's edition of Pliny, vol. v, p. 272. Hirt,
in his Essay on the Pantheon, places the date of Vitruvius's writings on
Architecture between the years 16 and 14 of our era.

36 Poggendorff s Annalen, Bd. xxxvii, s. 175 — 180.

3^ Carmine Lippi : Fu il fuoco o Vacqua eke sottcrd Pompei ed
Ercolanol (1816) p. 10.

'•& Scacchi, Osservaziom cntichc sulla maniera come fu seppcllita
fAntica Pompei, 1843, pp. 8—10.

430 COSMOS.

of seeing specimens of this pumice-stone in the interesting
geological collections of my learned friend and academical
colleague, Dr. Ewald. The similarity of the mineralogical
constitution at two opposite points naturally gives rise to
the question, — whether that which covers Pompeii has been
thrown down, as Leopold vcn Buch supposes, during the
eruption of the year 79, from the declivities of Somma, — or
whether, as Scacchi maintains, the newly-opened crater of
Vesuvius has ejected pumice simultaneously on Pompeii aiid
on Somma? What was known as pumex Pompejanus in
the time of Vitruvius, under Augustus ,carries us back to
eruptions before the time of Pliny, and from the experience
we have respecting the variable nature of the formations in
different ages and different circumstances of volcanic activity,
we should be as little warranted in absolutely denying that,
since its first existence, Vesuvius could have ejected pumice,
as we should be in absolutely taking it for granted that
pumice — that is to say, the fibrous or porous condition of a
pyrogenous mineral — could only be formed where obsidian
or trachyte with vitreous felspar (sanidine) were present.

Although, from the examples which have been cited of the
length of the periods at which the revival of a slumbering
volcano may take place, it is evident that much uncertainty
must still remain, yet it is of great importance to verify
the geographical distribution of burning volcanoes for a
determinate period. Of the 225 open craters through which,
in the middle of the 19th century, the molten interior of
the earth maintains a volcanic communication with the
atmosphere, 70, that is to say, one-third, are situated on the
continents, and 155, or two-thirds, on the islands of our
globe. Of the 70 continental volcanoes, 53, or three-fourths,
belong to America, 15 to Asia, 1 to Europe, and 1 or 2 to
that portion of the continent of Africa hitherto known to us.
In the South-Asiatic islands (the Sundas and Moluccas), as
well as in the Aleutian and Kurile Islands, the greatest num-
ber of the island volcanoes are situated in a very limited
space. The Aleutian Isles contain, perhaps, more volcanoes
active in late historical times than the whole continent of
South-America. On the whole surface of the earth, the tract
containing the greatest number of volcanoes is that which
ranges between 73° west and 127° east longitude, and

TRUE VOLCANOES. 431

between 47° south and 66° north latitude, in a direction
from south-east to north-west.

If we suppose the great gulph of the sea, known under
the name of the South Sea, or South Pacific Ocean, to be
cosmically bounded by the parallel of Behring's Straits, and
that of New Zealand, which is also the parallel of South
Chili and North Patagonia, we shall find — and this result
is very remarkable — in the interior of the basin, as well
as around it (on its Asiatic and American continental boun-
daries), 198, or nearly seven-eighths of the 225 still active
volcanoes of the whole earth. The volcanoes nearest the
poles are, so far as our present geographical knowledge goes,
in the northern hemisphere the volcano Esk, on the small
island of Jan Meyen, in lat. 71° 1', and west long. 7° 30' 30",
and in the southern hemisphere Mount Erebus, whose red
flames are visible even by day, and which Sir James Ross,39
on his great southern voyage of discovery in 1841, found to
be 12,400 feet high, or about 240 feet higher than the Peak
of Teneriffe, in lat. 77° 33', and long. 166° 58' 30" east.

The great number of volcanoes on the islands and on
the shores of continents must have early led to the investi-
gation by geologists of the causes of this phenomenon. I
have already, in another place (Cosmos, vol. i, p. 242), men-
tioned the confused theory of Trogus Pompeius under Augus-
tus, who supposed that the sea- water excited the volcanic fire.
Chemical and mechanical reasons for this supposed effect of
the sea have been adduced to the latest times. The old
hypothesis of the sea- water penetrating into the volcanic
focus seemed to acquire a firmer foundation at the time of the
discovery of the metals of the earth by Davy, but the great
discoverer himself soon abandoned the theory to which even
Gay-Lussac inclined,40 in spite of the rare occurrence, or total
absence of hydrogen gas. Mechanical, or rather dynamical
causes, whether sought for in the contraction of the upper
crust of the earth and the rising of continents, or in the
locally diminished thickness of the inflexible portion of the

39 Sir James Ross, Voyage to the Antartic Regions, vol. i, pp. 217,
220, and 3C4.

40 Gay-Lussac, Reflexions sur les Volcans in the Annales dc Chimie ct
de Physique, t. xxii, 1823, p. 429 ; see above, p. 169 ; Arago, (Euvret
completes, t. iii, p. 47.

432 COSMOS.

earth's crust, might, in my opinion, offer a greater appearance
of probability. It is not difficult to imagine that at the
margins of the up-heaving continents which now form the
more or less precipitous littoral boundary visible over the
surface of the sea, fissures have been produced by the simul-
taneous sinking of the adjoining bottom of the sea, through
which the communication with the molten interior is pro-
moted. On the ridge of the elevations, far from that area
of depression in the oceanic basin, the same occasion for
the existence of such rents does not exist. Volcanoes follow
the present sea-shore in single, sometimes double, and some-
times even triple parallel rows. These are connected by
short chains of mountains, raised on transverse fissures, and
forming mountain-nodes. The range nearest to the shore is
frequently (but by 110 means always) the most active, while
the more distant, those more in the interior of the country,
appear to be extinct or approaching extinction. It is some-
times thought that, in a particular direction in one and the
same range of volcanoes, an increase or diminution in the
frequency of the eruptions may be perceived, but the pheno-
mena of renewed activity after long intervals of rest render
this perception very uncertain.

As many incorrect statements of the distance of volcanic
activity from the sea are circulated, either through ignorance
of, or inattention to, the exact localities both of the volcanoes
and of the nearest points of the coast, I shall here give the
following distances in geographical miles (each being equal
to about 2030 yards, or 60 to a degree) : — In the Cordilleras
of Quito, the volcano of Sangay, which discharges uninter-
ruptedly, is situated in the most easterly direction, but its
distance from the sea is still 112 miles. Some very intelli-
gent monks attached to the mission of the Indies Andaquies
at the Alto Putumayo have assured me that on the upper
Rio de la Fragua,41 a tributary of the Caqueta, to the eastward
of the Ceja, they had seen smoke issue from a conical moun-

41 The position of the Volcan de la Fragua, as reduced at Timana, is
N. L. 1° 48', long. 75° 30' nearly. Compare the Carte Hypsometrique
des Nceuds de Montagnes dans les Cordilleres, in the large atlas of my
travels, 1831, pi. 5, see also pi. 22 and 24. This mountain, lying
isolated and so far to the east, ought to be visited by a geologist
capable of determining the longitude and latitude astronomically.

TRUE VOLCANOES. 433

tain of no great height, and whose distance from the coast
must have been 160 miles. The Mexican volcano of Jorullo,
which was elevated above the surface in September, 1759, is
84 miles from the nearest point of the sea-shore (see above,
pp. 314-321) ; the volcano of Popocatepetl is 132 miles; an
extinct volcano in the eastern Cordilleras of Bolivia, near S.
Pedro de Cacha, in the vale of Yucay (see above, p. 295),
is upwards of 180 miles ; the volcanoes of the Siebenge-
birge, near Bonn, and of the Eifel (see above, p. 231 — 238),
are from 132 to 152 miles; those of Auvergne, Velay, and
Vivarais,43 distributing them into three separate groups (the
group of the Puy de Dome, near Clermont, with the Mont
Dore, the group of the Cantal. and the group of the Puy and
Mezenc), are severally 148, 116, and 84 miles distant from
the sea. The extinct volcanoes of Olofc, south of the Pyrenees,
west of Gerona, with their distinct and sometimes divided
lava-streams, are distant only 28 miles from the Catalonian
shores of the Mediterranean, while, on the other hand, the
undoubted, and to all appearances very lately extinct, vol-
canoes in the long chain of the Rocky Mountains, in the
north-vest of America, are situated at a distance of from 600
to 680 miles from the shore of the Pacific.

A very abnormal phenomenon in the geographical distri-
bution of volcanoes is the existence in historical times of
active, and partially, perhaps, even of burning volcanoes in
the mountain-chain of the Thian-shan (the Celestial Moun-
tains), between the two parallel chains of the Altai and the
Kueii-lun. The existence of these volcanoes was first made
known by Abel-Rernusat and Klaproth, and I have been
enabled, by the aid of the able and laborious investigations of

42 In these three groups which, according to the old geographical
nomenclature, belong to Auvergne, the Vivarais, and the Velay, the
distances given in the text are those of the northernmost parts of each
group as taken from the Mediterranean Sea (between the Golfe d'Aigues
Mortes and Cette). In the first group, that of the Puy de Dome, a
crater erupted in the granite near Man/at, called Le Gour de Tazena,
is taken as the most northerly point (Rozet. in the Mem. de la Societe
Geol. de France, t. i, 1844, p. 119). Farther south than the group of
the Cantal, and therefore nearest the sea-shore, lies the small volcanic
district of la Guiolle near the Monts d'Aubrac, norta-west of Chirac,
and distant scarcely 72 geographical miles from the sea. Compare tL»
Carte Geotoyique de la France, 1841.

VOL. V. 2 F

434 COSMOS.

Stanislas Julien, to treat of them fully in my work on Central
Asia.43 The relative distances of the volcano of Pe-.shan

43 Humboldt, Asie Centrale, t. ii, pp. 7 — 61, 216, and 335—364;
Cosmos, vol. i, p. 244. The mountain-lake of Issikul, on the northern
slope of the Thian-shan, which was lately visited for the first time by
Eussian travellers, I found marked on the famous Catalonian map of
1374,* which is preserved as a treasure among the manuscripts of the
Paris library. Strahlenberg, in his work entitled Der nb'rdliche und
ostliclie Theil von Europa und Asien (Stockholm, 1730, s. 327), has the
merit of having first represented the Thian-shan as a peculiar and inde-
pendent chain, without however being aware of its volcanic action. He
gives it the very indefinite name of Mousart, which, — as the Bolor was
designated by the general title of M us tag, which particularizes nothing,
and merely indicates snow, — has for a whole century occasioned an
erroneous representation, and an absurd and confused nomenclature of
the mountain-ranges to the north of the Himalaya, confounding meridian
and parallel-chains with each other. Mousart is a corruption of the
Tartaric word Muztay, synonymous with our expression snowy chain,
the Sierra Nevada of the Spaniards, the Himalaya in the Institutes of
Menu, — signifying the habitation (alaya)o£ snow(/ama), and the Sineshan
of the Chinese. Eleven hundred years before Strahleuberg wrote, under
the dynasty of Sui, in the time of Dagobert, king of the Franks, the
Chinese possessed maps, constructed by order of the Government, of
the countries lying between the Yellow River and the Caspian
Sea, on which the Kuen-liin and the Thian-shan were marked. It was
undoubtedly these two chains, but especially the first, as I think I have
shown in another place (Asie Centr. t. i, pp. 118 — 129, 194—203, and
t. ii, p. 413—425), which, when the march of the Macedonian army
had brought the Greeks into closer acquaintance with the interior of
.Asia, spread among their geographers the knowledge of a belt of
mountains extending from Asia Minor to the eastern sea, from India
and Scythia to Thin®, thus cutting the whole continent into two
halves (Strabo, lib. i, p. 68, lib. xi, p. 490). Dicsearchus, and after him
Eratosthenes, denominated this chain the elongated Taurus; the
Himalaya chain is included under this appellation. " That which
bounds India on the north," we are expressly told by Strabo (lib. xv,
p. 689), " from Ariane to the eastern sea, is the extremest portions of
the Taurus, which are separately called by the natives Paropamisos,
Emodon, Imaon, and other names, but which the Macedonians call the
Caucasus." In a previous part of the book, in describing Pactriana and
Sogdiana (lib. xi, p. 519), he says, "the last portion of the Taurus,
which is called Imaon, touches the Indian (eastern) Sea." The terms
"on this side and on that side the Taurus," had reference to what was

[* This curious Spanish map was the result of the great commercial
relations which existed at that time between Majorca and Italy, Egypt
and India. See a more full notice of it in Asie Centrale, loc. cit. — TK.]

TRUE VOLCANOES. 435

(Mont Blanc) with its lava-streams, and the still burning

believed to be a single range running east and west ; that is to say, a
parallel-chain. Strabo was aware of this, for he says, " the Greeks call
the half of the region of Asia looking to the north this side the Taurus,
and the half towards the south that side" (lib. ii, p. 129). In the later
times of Ptolemy, however, when commerce in general, and particularly
the silk-trade, became animated, the appellation of Imaus was trans-
ferred to a meridian chain, the Bolor, as many passages of the 6th book
show (Asie Centr. t. i, pp. 146—162). The line in which, parallel to the
equator, the Taurus range intersects the whole region, according to
Hellenic ideas, was first called by Dicaearchus, a pupil of the Stagirite,
a Diaphragma (partition-wall), because, by means of perpendicular lines
drawn from it, the geographical width of other points could be measured.
The diaphragma was the parallel of Rhodes, extended on the west to
the pillars of Hercules, and on the east to the coast of Thinse (Agathe-
meros in Hudson's Geogr. Gr. Min., vol. ii, p. 4). The divisional line of
Dicaearchus, equally interesting in a geological and an orographical point
of view, passed into the work of Eratosthenes, who mentions it in the
3rd book of his description of the earth, in illustration of his table of
the inhabited world. Strabo places so much importance on this direc-
tion and partition line of Eratosthenes that he (lib. i, p. 65) thinks it
possible " that on its eastern extension, which at Thinse passes through
the Atlantic Sea, there might be the site of another inhabited world,
or even of several worlds ;" although he does not exactly predict that
they will be found to exist. The expression "Atlantic Sea" may
seem remarkable as used instead of the " eastern sea," as the south sea
(the Pacific) is usually called, but as our Indian Ocean, south of Bengal,
is called in Strabo the Atlantic South Sea, so were both seas to the
south-east of India considered to be connected, and were frequently
confounded together. Thus, we read, lib. ii, p. 130, " India, the largest
and most favoured country, which terminates at the eastern sea and
at t'iie Atlantic South Sea," and again, lib. xv, p. 689, "the southern
and eastern sides of India, which are much larger than the other sides,
run into the Atlantic Sea," in which passage, as well as in the one
above quoted regarding Thinse (lib. i, p. 65), the expression " eastern sea"
is even avoided. Having been uninterruptedly occupied since the year
1792 with the strike and inclination of the mountain-strata, and their
relation to the bearings of the ranges of mountains, I have thought
it right to point attention to the fact that, taken in the mean, the
equatorial distance of the Kuen-liin, throughout its whole extent, as
well as in its western prolongation by the Hindu-Kho, points towards
the basin of the Mediterranean Sea and the Straits of Gibraltar (Asie
Centr., t. i, pp. 118 — 127, and t. ii, pp. 115 — 118), and that the sinking
of the bed of the sea in a great basin which is volcanic, especially on
the northern margin, may very possibly be connected with this up-
heaval and folding in. My friend, Elie de Beaumont, so thoroughly
acquainted with all that relates to geological bearing?, is opposed to
these views on loxodromical principles (Notice sur les Syttcmcs de
Afontagnes, 1852, t. ii, p. 667).

2F2

436 COSMOS.

igneous mountain (Hot&cheu) of Turfan, from the shores of
the Polar Sea and the Indian Ocean, are almost equally great,
about 1480 and 1520 miles. On the other hand, the distance
of Pe-shan, whose eruptions of lava are separately recorded,
from the year 89 of our era up to the 7th century, in Chinese
works, from the great mountain-lake of Issikul to the descent
of the Temurtutagh (a western portion of the Thian-shan) is
only 172 miles, while from the more northerly situated lake
of Balkasch, 148 miles in length, it is 208 miles distant.4*
• The great Dsaisang lake, in the neighbourhood of which I was
during my stay in the Chinese Dsungarei in 1829, is 360 miles
distant from the volcanoes of Thian-shan. Inland waters
are therefore not wanting, but they are certainly not in such
propinquity as that which the Caspian Sea bears to the still
active volcano of Demavend in the Persian Mazenderan.

While, however, basins of water, whether oceanic or in-
land, may not be requisite for the maintenance of volcanic
activity, — yet, if islands and coasts, as I am inclined to
believe, abound more in volcanoes only because the elevation
of the latter, produced by internal elastic forces, is accom-
panied by a neighbouring depression in the basin of the sea,45
so that an area of elevation borders on an area of depres-
sion, and that at this bordering-line large and deeply pene-
trating fissures and rents are produced, — it may be supposed
that in the central Asiatic zone, between the parallels of
41° and 48,° the great Aralo-Caspian area of depression, as
well as the large number of lakes, whether disposed in ranges
or otherwise, between the Thian-shan and the Altai-Kurts-
chum, may have given rise to littoral phenomena. We know
from tradition that many small basins now ranged in a row
like a string of beads (lacs a chapelet} once upon a time
formed a single large basin. Many large lakes are seen to
divide and form smaller ones from the disproportion be-
tween precipitation and evaporation. A very experienced
observer of the Kirghis Steppe, General Genz of Oren-
burg, has conjectured that there formerly existed a water-

44 See above, p. 358.

45 See Arago, Sur la cause de la depression d'une grande partie
de 1'Asie et sur le phenomene que les pentes les plus rapides des
chaines de montagnes sont (ge'ueralement) tourne'es vers la r

plus voisine, in his Astronomie Populaire, t. iii. pp. 1266—1274.

rner la

TRUE VOLCANOES. 437

communication between the Sea of Aral, the Aksakal,
the Sary-Kupa and the Tschagli. A great furrow is
observed, running from south-west to north-east, which
may be traced by the way of Omsk, between Irtisch and
Obi, through the steppe of Barabinsk, which abounds in
lakes, towards the moory plains of the Samoiedes, towards
Beresow and the shore of the Arctic Ocean. With this
furrow is probably connected the ancient and wide-spread
tradition of a Sitter Lake (called also the Dried Lake,
Hanhai) which extended eastward and southward from
Hanii, and in which ' a portion of the Gobi, whose salt and
reedy centre was found by Dr. von Bunge's careful baro-
metrical measurement to be only 2558 feet above the level
of the sea, rose in the form of an island.46 It is a geological
fact, which has not hitherto received its due share of atten-
tion, that seals, exactly similar to those which inhabit the
Caspian Sea and the Baikal in shoals, are found upwards of
400 miles to the east of the Baikal in the small fresh-water
lake of Oron, only a few miles in circumference. The lake
is connected with the Witim, a tributary of the Lena, in
which there are no seals.47 The present isolation of these
animals and their distance from the mouth of the Volga
(fully 3600 geographical miles) form a remarkable geological
phenomenon, indicative of an ancient and extensive con-
nection of waters. Can it be that the numerous depressions
to which, throughout a large tract of country, this central
part of Asia has been exposed, have called forth exception-
ally, on the convexity of the continental swelling, conditions
similar to those pi^oduced on the littoral borders of the fis-
sures of elevation ?

From reliable accounts rendered to the Emperor Kanghi,
we are acquainted with the existence of an extinct volcano
far to the east, iu the north-western Mantschurei, in the
neighbourhood of Mergen (probably in lat. 48^° and long.
122° 20' east). The eruption of scoriae and lava from the
mountain of Bo-shan or Ujun-Holdongi (the Nine Hills)

46 Klaproth, Asia Polyglotta, p. 232, and Memoires relatifs & TAsie
(from the Chinese Encyclopedia, published by command of the Em-
peror Kang-hi, in 1711), t. ii. p. 342 ; Humboldt, Asie Centrale, t. ii,
pp. 125 and 135—143.

4? Pallas, Zoographia Rosso-Asiatica, 1811, p. 115.

438 COSMOS.

from 12 to 16 miles in a south-westerly direction from
Margen, took place in January 1721. The mounds of scoriae
thrown out on that occasion, according to the report of the
persons sent by the Emperor Kanghi to investigate the cir-
cumstances, were 24 geographical miles in circumference ; it
was likewise mentioned that a stream of lava, damming up
the water of the river Udelin, had formed a lake. In the
7th century of our era the Bo-shan is said to have had a
previous igneous eruption. Its distance from the sea is
about 420 geographical miles, similar to that of the Him-
alaya/8 so that it is upwards of three times more distant than

B It is not in the Himalaya range, near the sea (some portions of it
between the colossai Kunchinjinga and Shamalari, approach the shore
of the Bay of Bengal within 428 aud 376 geographical miles), that the
volcanic action has first burst forth, but in the third, or interior,
parallel chain, the Thian-shan, nearly four times as far removed from
the same shore, and that under very special circumstances, the subsi-
dence of ground in the neighbourhood deranging strata and causing
fissures. We learn from the study of the geographical works of the
Chinese, first instigated by me and afterwards continued by my friend
Stanislas Julien, that the Kuen-lun, the northern boundary range of
Tibet, the Tsi-shi-shan of the Mongols, also possesses in the hill of
Shin-Khieu a cavern emitting uninterrupted flames (Asie Centrale, t. ii,
pp. 427 — 467 and 483). The phenomenon seems to be quite analogous
to the Chimasra in Lycia, which has now been burning for several
thousands of years (see above, p. 256 — 7, and note 51) ; it is not a
volcano, but a fire-spring, diffusing to a great distance an agreeable
odour (probably from containing r aphtha?). The Kuen-liin which,
like me in the Asie Centrale (t. i, p. 127 and t. ii, p. 431), Dr. Thomas
Thomson, the learned botanist of Western Tibet (Flora Indica, 1855,
p. 253), describes as a continuation of the Hindu-Kho, which is
joined from the south-east by the Himalaya chain, approaches this
chain at its western extremity to such a degree that my excellent
friend, Adolph Schlagintweit, designates " the Kuen-liin and the
Himalaya on the west side of the Indus, not as separate chains, but
as one mass of mountains." (Report No. ix of the Magnetic Survey in
India ly Ad. Schlagintweit, 1856, p. 61). In the whole extent towards
the east, however, as far as 92° 20' east longitude, in the direction of
the starry lake, the Kuen-liin forms, as was shown so early as the 7th
century of our era by minute descriptions given under the Dynasty of
Sai (Klaproth, Tableaux Historiques de I' Asie, p. 204), an independent
chain running east and west parallel to the Himalaya at a distance of
about 7^ degrees of latitude. The brothers Hermann and Robert
Schlagintweit are the first who have had the courage and the good
fortune to traverse the chain of the Kuen-liin, setting out from Ladak
and reaching the territory of Khotau in the months of July and Sep-
tember, 1856. According to their observations, which are always

TRUE VOLCANOES. 439

the volcano of Jorullo. We are indebted for these remark-
able geosnostic accounts from the Mantschurei to the in-
dustry of W. P. Wassiljew (Q-eog. Bote, 1855, Heft, v, s. 31)
and to an essay by M. Semenow (the learned translator of
Carl Hitter's great work on Geology) in the 17th vol. of the
Proceedings of the Imperial Russian Geographical Society.

In the course of the investigations into the geographical
distribution of volcanoes, and their frequent occurrence on
islands and sea-coasts, that is to say, on the margins of con-
tinental elevations, the probable great inequality in the
depth to which the crust of the earth has hitherto been
penetrated has also been frequently brought under con-
sideration. One is disposed to believe that the surface of
the internal molten mass of the earth's body lies nearest to
those points at which the volcanoes have burst forth. But
as it may be conceived that there are many intermediate
degrees of consistency in the solidifying mass, it is difficult
to form a clear idea of any such surface of the molten
matter ; if a change in the comprehensive capacity of the
external firm and already solidified shell, be supposed to
be the chief cause ot all the subversions, fissures, upheavals
and basin-like depressions. If we might be allowed to
determine what is called the thickness of the earth's crust
in an arithmetical ratio deduced from experiments drawn
from. Artesian wells, and from the fusion-point of granite,
that is to say, by taking equal geothermal degrees of
depth,49 we should find it to be 20 ^ geographical miles
or 3-y^th of the Polar diameter.60 But the influences of

extremely careful, the highest water-shedding mountain-chain is that
on which is situated* the Karakorum pass (18,304 feet) which, stretching
from south-east to north-west, lies parallel to the opposite southerly
portion of the Himalaya (to the west of Dhawalagiri). The rivers
Yarkland and Karakasch, which form a part of the great water system
of the Tarim and Lake Lop, rise on the north-eastern slope of the
Karakorum chain. From this region of water-springs the travellers
arrived by way of Kissilkorum and the hot springs (120° F.) at the
small mountain lake of Kiuk-kiul, on the chain of the Kuen-liin
which stretches east and west (Report Xo. viii, Agra, 1857, p. 6).

4%J Cosmos, vol. i, pp. 26, 167; see above, pp. 34 — 38.

50 Arago (Astron. Populaire, t. iii, p. 248) adopts nearly the same
thickness of the earth's crust, namely, 40,000 metres, or about 22
miles; Elie de Beaumont (Systemes de Montagncs, t. iii, p. 1237), cal-
culates the thickness at about £ more. The oldest calculation is that

440 COSMOS.

the pressure and of the power of conducting heat exercised
by various kinds of rock, render it likely that the geo-
thermal degrees of depth increase in value in proportion as
the depth itself increases.

Notwithstanding the ve'ry limited number of points at
which the fused interior of our planet now maintains an
active communication with the atmosphere, it is still not
unimportant to inquire in what manner and to what extent
the volcanic exhalations of gas operate on the chemical
composition of the atmosphere, and through it, on the or-
ganic life developed on the earth's surface. We must, in the
first place, bear in mind that it is not so much the summit-
craters themselves as the small cones of ejection and the
fumaroles, which occupy large spaces and surround so many
volcanoes, that exhale gases, — and that even whole tracts of
country in Iceland, in the Caucasus, in the high land of
Armenia, on Java, the Galapagos, the Sandwich Islands and
New Zealand, exhibit a constant state of activity through
solfataras, naphtha-springs, and salses. Volcanic districts,
which are now reckoned among those which are extinct, are
likewise to be regarded as sources of gas, and the silent
working of the subterranean forces, whether destructive
or formative, within them is, with regard to quantity, pro-
bably more productive than the great, noisy, and more rare
eruptions of volcanoes, although their lava-fields continue to
smoke either visibly or invisibly for years at a time. If it
be said that the effects of these small chemical processes
can be but little regarded, for that the immense volume of
the atmosphere, constantly kept in motion by currents of
air, could only be affected in its primitive mixture to a very
small extent through means of such apparently unimportant
additions,61 it will be necessary to bear in mind the powerful
of Cordier, in mean value 56 geographical miles, an amount which,
according to Hopkins's mathematical theory of stability, would have
to be multiplied fourteen times, and would give between 688 and
860 geographical miles. I quite concur on geological grounds in the
doubts raised by Naumann in his admirable Lelirluch der Geognosie
(vol. i, p. 62 — 64, 73 — 76 and 289), against this enormous distance of
the fluid interior from the craters of the active volcanoes.

11 A remarkable example of the way in which perceptible changes
of mixture are produced in nature by very minute, but continuous,
accumulation is afforded by the presence of silver in sea-water,
which was discovered by Malaguti and confirmed by Field. Not-

TRUE VOLCANOES. 441

influence exerted, according to the admirable investigations
of Percival, Saussure, Boussingault and Liebig, by three 01
four ten-thousandth parts of carbonic acid in our atmo-
sphere on the existence of the vegetable organism. From
Bunsen's excellent work on the different kinds of volcanic
gas, it appears that among the fumaroles of different stages
of activity and local diversity, some (as for example at Hecla)
yield from 0.81 to 0.83 of nitrogen, and in the lava-streams
of the mountain 0.78, with mere traces (0.01 to 0.02) of
carbonic acid, while others in Iceland, as for instance near
Krisuvik, on the contrary, yield from 0.86 to 0.87 of car-
bonic acid, with scarcely 0.01 of nitrogen.62 We find like-
wise in the important work on the emanations of gas in
Southern Italy and Sicily by Charles Sainte-Claire Deville
and Bornemann, that there is an immense proportion of
nitrogen gas (0.98) in the exhalations of a fissure situated
low down in the crater of Vulcano, while the sulphuric
acid vapours show a mixture of 74.7 nitrogen gas and 18.5
oxygen, a proportion which approaches pretty nearly to the
composition of the atmospheric air. On the other hand the
gas which rises from the spring of Acqua Santa53 in Catania
is pure nitrogen gas, as was also the gas of the Yolcancifcos
de Turbaco at the time of my American journey.64

Are we to conclude that the great quantity of nitrogen
dispersed through the medium of volcanic action consists of
that alone which is imparted to the volcanoes by meteoric
water ? — or are there internal and deeply-seated sources of
nitrogen ? It must also be borne in mind that the air dis-
solved in rain-water does not contain, like the atmosphere,
0.79 of nitrogen, but according to my own experiments, only

withstanding the immense extent of the ocean and the trifling
amount of surface presented to it by the ships which traverse it,
yet the trace of silver in the sea-water has in recent times become
observable on the copper-sheeting of ships.

62 Bunsen, Ueber die chemischen Prozesse der rullcanischen Gesteins-
bildungen in Poggend. Annalen, Bd. Ixxxiii, s. 242 and 246.

53 Comptes rendus de FAcad. des Sciences, t. xliii, 1856, pp. 366
and 689. The first correct analysis of the gas which rushes with noise
from the great solfatara of Pozzuoli, and which was collected with
great difficulty by M. Ch. St.-Claire Deville, gave the following results :
— sulphurous acid (acide sulfureux) 24.5, — oxygen 14.5, — and nitrogen
61.4.

* See above, pp. 211- 218.

COSMOS.

O.G9. Nitrogen is a source of increased fertility,58 by the
formation of ammonia, through the medium of the almost
daily electrical explosions in tropical countries. The influ-
ence of nitrogen on vegetation is similar to that of the sub-
stratum of atmospheric carbonic acid.

In analysing the different gases of the volcanoes which
lie nearest to the equator (Tolima, Purace, Pasto, Tuqueres
and Cunibal) Boussingault has discovered, along with a great
deal of aqueous vapour, carbonic acid and sulphuretted
hydrogen gas, but no muriatic acid, no nitrogen and no free
hydrogen.56 The influence still exercised by the interior of
our planet on the chemical composition of the atmosphere
in withdrawing this matter in order to give it out again
under other forms, is certainly but an insignificant part of
the chemical revolutions which the atmosphere must have
undergone in remote ages on the eruption of great masses of
rock from open fissures. The conjecture as to the probability
of a very large portion of carbonic acid gas in the ancient

55 Boussingault, Economic rurale (1851), t. ii, p. 724 — 726; — "The
permanency of storms in the interior of the atmosphere (within the
tropics) is an interesting fact, being connected with one of the most
important questions in the physical history of the globe, namely, that
of the fixation of the nitrogen of the air in organised beings. When-
ever a series of electric sparks passes through the humid atmosphere,
the production and combination of nitric acid and ammonia take place.
The nitrate of ammonia uniformly accompanies the rain during a storm,
and being by nature fixed, it cannot maintain itself in the state of
vapour; carbonate of ammonia is found in the air, and the ammonia
of the nitrate is carried to the earth by the rain. Thus it appears, in
fact, to be an electric action which disposes the nitrogen of the atmo-
sphere to become assimilated by organised beings. In the equinoxial
zone, throughout the whole year, every day, and probably even every
moment, there is a continual succession of electric discharges going on.
An observer, stationed at the equator, if he were endowed with organs
sufficiently sensitive, would hear without intermission the noise of thun-
der." Sal ammoniac, however, together with common salt, are from
time to time found as products of sublimation, even in lava-streams, —
on Hecla, Vesuvius, and Etna, in the volcanic chain of Guatemala (the
volcano of Izalco), and above all in Asia in the volcanic chain of the
Thian-shan. The inhabitants of the country between Kutsch, Turfan,
and Kami pay their tribute to the Emperor of China in certain years
in sal ammoniac (in Chinese nao-sha, in Persian nushadcn), which is an
important article of internal trade. (Asie Centrale, t. ii, pp. 33, 38, 45,
and 428.)

M Viajcs de Boussingault (1849) p. 78.

TRUE VOLCANOES. 443

aeriform envelope is strengthened by a comparison of the
thickness of the present seams of coals with that of the
thin coal-strata (seven lines in thickness) which, according
to Chevandier's calculations, our thickest woods in the
temperate zone would yield to the soil in the course of
100 years.57

In the infancy of geognosy, previous to Do'lomieu's ingenious
conjectures, the source of volcanic action was not placed
below the most ancient rock-formations, which were then
generally supposed to be granite and gneiss. Besting on
some feeble analogies of inflammability, it was long believed
that the source of volcanic eruptions, and the emanations of
gas to which . they for many centuries give rise, was to be
sought for in the later, upper-silurian floetz-strata, containing
combustible matter. A more general acquaintance with
the earth's surface, profounder and more strictly conducted
geological investigations, together with the beneficial influence
which the great advances made by modern chemistry have
exercised on the study of geology, have taught us that the
three great groups of volcanic or eruptive rock (trachyte,
phonolite, and basalt), when viewed as large masses, appear
when compared together to be of different ages, and for the
most part widely separated from each other. All three, how-
ever, have come later to the surface than the Plutonic gra-
nite, the diorite, and the quartz-porphyry, — later than all the
silurian, secondary, tertiary, and quartary (pleistocene) for-
mations,— and that they frequently traverse the loose strata
of the diluvial formations and bone-breccias. A striking
variety68 of these intersections, compressed into a small space,
is exhibited, as we learn from Rozet's observations, in Au-
vergne. While the great trachytic mountain -masses of the
Cantal, Mont-Dore, and Puy de Dome, penetrate the granite

57 Cosmos, vol. i, pp. 283 — 5.

53 Kozet, Memoire sur les Volcans d'Auvergne, in the Memoires de la,
Soc. Geol. de France, 2me Serie, t. i, 1844, pp. 64 and 120—130 :— "The
basalts (like the trachytes) have penetrated through the gneiss, the
granite, the coal formations, the tertiary formations, and the oldest
diiuvian beds. The basalts are even frequently seen overlying masses
of basaltic boulders j they have issued from an infinite number of
openings, several of which are still perfectly recognisable. Many of
them exhibit cones of scorise more or less considerable, but nowhere do
we find craters similar to those which have given out streams of lava."

414 COSMOS.

itself, and at the same time enclose in some parts (for ex-
ample, between Vic and Aurillac, and at the Giou de Mamon)
large fragments of gneiss59 and limestone, we find also the
trachyte and basalt intersecting as dykes the gneiss, and the
coal-beds of the tertiary and diluvial strata. Basalt and
phonolite, closely allied to each other, as the Auvergne and the
central mountains of Bohemia prove, are both of more recent
formation than the trachytes, which are frequently tra-
versed in layers by basalts.60 The phonolites are, on the
other hand, more ancient than the basalts ; where they pro-
bably never form dykes, but on the contrary dykes of basalt
frequently intersect the porphyritic-schist (phonolite). In
the chain of the Andes belonging to Quito, I have found the
basalt-formation a great distance apart from the prevailing
trachytes ; almost solely at the Rio Pisque and in the valley
of Guaillabamba.61

As in the volcanic elevated plain of Quito everything is
covered with trachytes, trachytic-conglomerates, and tufas, it
was my most earnest endeavour to discover, if possible, some
point at which it might be clearly seen on which of the older
rocks the mighty cone and bell- shaped mountains are placed,
or, to speak more precisely, through which of them they
had broken forth. Such a point I was so fortunate as to
discover in the month of June 1802, on my way from Rio-
bamba Nuevo (9483 feet above the surface of the South
Pacific) when I attempted to ascend the Tunguragua on the

59 Resembling the granitic fragments imbedded in the trachyte of
Jorullo. See above, p. 321.

60 Also in the Eifel, according to the important testimony of the
mine-director, Von Dechen. See above, p. 237.

61 See above, p. 333. The Rio de Guaillabamba flows into the
Rio de las Esmeraldas. The village of Guaillabamba, near which I
found the isolated oliviniferous basalt, is only 6430 feet above the level
of the sea. An intolerable heat prevails in the valley, which is still
more intense in the Valle de Chota, between Tusa and the Villa cle
Ibarra, the sole of which sinks to 5288 feet, and which is rather a chasm
than a valley, being scarcely 9600 feet wide and 4800 feet deep (Hum-
boldt, Rec. d' Observations Astronomiques, vol. i, p. 307), The rubbish-
ejecting Volcan de Ansango, on the descent of the Antisana, does not
belong to the basalt-formation at all ; it is an oligoclase-trachyte resem-
bling basalt (compare, for the distances, Antagonisme des Basalt.es et des
Trachytes, my Essai Geognostique sur le gisement des Roches, 1823, pp.
848 and 359, and generally, pp. 327—336).

TRUE VOLCANOES. 445

side of the Cucliilla de Guandisava. I proceeded from the
delightful village of Penipe over the swinging rope-bridge
(puente de maroma) of t'he Rio Puela to the isolated Ha-
cienda de Guansce (7929 feet), where to the south-east, op-
posite the point at which the Rio Blanco falls into the Rio
Chambo, rises a splendid colonnade of black trachyte resem-
bling pitch-stone. It looks at a distance like the basalt-
quarry at Unkel. At Chiruborazo, a little higher than the
basin of Yana-Cocha, I saw a similar group of trachytic
columns of greater height but less regularity. The columns to
the south-east of Penipe are mostly pentagonal, only 14 inches
in diameter, and frequently bent and diverging. At the foot
of this black trachyte of Penipe, not far from the mouth of
the Rio Blanco, a very unexpected phenomenon presents
itself in this part of the Cordilleras j — greenish- white mica-
slate with garnets interspersed in it, and farther on, beyond
the shallow stream of Bascaguan, at the hacienda of Guansce,
near the shore of the Rio Puela, and probably dipping be
low the mica-slate granite of a middling-sized grain, with
light reddish felspar, a small quantity of blackish green mica
and a great deal of greyish white quartz. There is no horn-
blend, nor is there any syenite. Thus it appears that the
trachytes of the volcano of Tungurahua, resembling those
of Chimborazo in their mineralogical condition, that is to
say, consisting of a mixture of oligoclase and augite,
have here penetrated granite and mica-slate. Farther
towards the south, and a little to the east of the road
leading from Riobamba Nuevo to Guamote and Ticsan, in
that part of the Cordilleras which recedes from the sea-shore,
the rocks formerly called primitive, mica-slate and gneiss,
make their appearance everywhere, towards the foot of the
colossal altar de los Collanes, the Cuvillan, and the Paramo
del Hatillo. Previous to the arrival of the Spaniards; and
even before the dominion of the Incas extended so far to the
north, the natives are. said to have worked metalliferous
beds in the neighbourhood of the volcanoes. A little to the
south of San Luis numerous dykes of quartz are observed
running through a greenish clay-slute. At Guamote, at the
entrance to the grassy-plain of Tiocaxa, we found large masses
of rock consisting of quartzites very poor in mica, of a dis-
tinct linear parallel structure, running reg^arly at an angle

446 COSMOS.

of 70 degrees to the north. Farther to the south at Ticsan,
not far from Alausi, the Cerro Cuello de Ticsan shows
large masses of sulphur imbedded in a layer of quartz,
subordinate to the neighbouring mica-slate. So great a diffu-
sion of quartz in the neighbourhood of trachytic volcanoes
appears at first sight somewhat strange. The observations
which I made, however, of the overlying, or rather of the
breaking forth of trachyte from mica-slate and granite at the
loot of the Tungurahua (a phenomenon as rare in the Cor-
dilleras as frequent in Auvergne) have been confirmed, after
an interval of 47 years, by the admirable investigations of
the French Geologist Sebastian Wisse at the Sangay.

That colossal volcano, 1343 feet higher than Mont-Blanc,
entirely destitute of lava-streams (which Charles Deville de-
clares are also wanting in the equally active Stromboli) but
ejecting uninterruptedly, at least since the year 1728, a black,
and frequently brightly glowing rock, forms a trachy tic-
island of scarcely 8 geographical miles in diameter62 in the
midst of beds of granite and gneiss. A totally opposite
condition of stratification is exhibited in the volcanic district

62 S^bastien Wisse, Exploration du Volcan de Sangay, in the Comptes
rendus de I'Acad. des Sciences, t. xxxvi, 1853, p. 721 ; comp. also above,
p. 251.

According to Bo ussingault, the ejected fragments of trachy te brought
home by Wisse and collected on the upper descent of the cone (the
traveller reached an elevation of 960 feet below the summit, which is
itself 485 feet in diameter), consist of a black, pitch-like fundamental
mass, in which are imbedded crystals of glassy (?) felspar. It is a very
remarkable phenomenon, and one which up to the present time seems
to stand alone in the history of volcanic ejections that, along with these
large black pieces of trachyte, small sharp-edged fragments of pure
quartz are thrown out. According to a letter from my friend Boussin-
gault, dated January 1851, these fragments are no longer than 4 cubic
centimetres in bulk. No quartz is found disseminated in the trachytic
mass itself. All the volcanic trachytes which I have examined in the
Cordilleras of South America and Mexico, and even the trachytic por-
phyries in which the rich silver veins of Real del Monte, Moran and
Regla are contained, to the north of the elevated valley of Mexico, are
entirely destitute of quartz. Notwithstanding this seeming antagonism,
however, of quartz and trachyte in still-active volcanoes, I am by no
means inclined to deny the volcanic origin of the " trachytes et porphy-
res meulieres (mill-stone trachytes)" to which Beudant first drew atten-
tion. The mode, however, in which these are formed, being erupted
frcrn fissures, is entirely different from the formation of the conical and
dome-like trachyte structures.

TRUE VOLCANOES. 447

of Eifel, as I have already observed, both from the activity
which once manifested itself in the Maars (or mine-funnels)
sunk in the Devonian-schist, and that shown in the raised
structures from which lava-streams flow, as on the long ridge
of the Mosenberg and Gerolstein. The surface does not here
indicate what is hidden in the interior. The absence of tra-
chyte in volcanoes which were so active thousands of years
ago, is a still more striking phenomenon. The augitiferous
scoriae of the Mosenberg, which partly accompany the basaltic
lava-stream, contain small burnt pieces of schist, but no
fragments of trachyte, and in the neighbourhood the tra-
chytes are absent. This species of rock is only to be seen
in the Eifel in a state of entire isolation63 far from the Maars
and lava-yielding volcanoes, as in the Seliberg at Quiddel-
bach, and in the mountain-chain of Reimerath. The different
nature of the formations through which the volcanoes force
their way so as to operate with power on the outer crust of
the earth is geologically as important as the material which
they throw out.

The conditions of configuration in those rocky structures
through which volcanic action manifests itself, or has en-
deavoured to do so, have at length been in modern times far
more completely investigated and described in their often
very complicated variations in the most distant quarters of
the globe than in the previous century, when the entire
morphology of volcanoes was limited to conical and bell-
shaped mountains. There are many volcanoes whose confi-
guration, altitude and range (what the talented Carl Frie-
drich JSTaumann calls the geotectonics),64 we now know in
the most satisfactory manner, while we continue in the
greatest ignorance regarding the composition of their diffe-
rent rocks and the association of the mineral species which
characterise their trachytes, and which are recognisable

63 See above, pp. 232—6.

64 The fullest information we possess on any volcanic district, founded
on actual measurements of altitudes, angles of inclination, and profile
views, is contained in the beautiful work of the Astronomer of Olmiitz,
Julius Schmidt, on Vesuvius, the solfatara, Monte Nuovo, the Astroni,
Eocca Monfina and the old volcanoes of the Papal territory (in the A>
banian Mountains, Lago Bracciano, and Lago di Bolsena). See his hyp-
Eometrical work, Die Eruption dcs Vcsuvs im Mai, 1855, with Atlas,
plates iii, iv. iz.

4i8 COSMOS.

apart from the principal mass. Both kinds of knowledge,
however, — the morphology of the rocky piles and the oryc-
tognosy of their composition, — are equally necessary to the
perfect understanding of volcanic action ; nay, the latter,
founded on crystallisation and chemical analysis, on account
of the connection with plutonic rocks (porphyritic quartz,
greenstone and serpentine) is of even greater geognostic im-
portance. The little we believe we know of what is called
the volcanicity of the Moon depends too, from the very na-
ture of the knowledge, on configuration alone65.

65 The progressive perfection of our acquaintance with the formation
of the surface of the Moon as derived from numerous observers, from
Tobias Mayer down to Lohrmann, Miidler and Julius Schmidt, has
tended on the whole rather to diminish than to strengthen our belief
in great analogies between the volcanic structures of the earth and
those of the moon ; not so much on account of the conditions of di-
mension and the early recognised ranging of so many ring-shaped
mountains, as on account of the nature of the rills and of the system of
rays which cast no shadows (radiations of light) of more than 400 miles
in length and from 2 to 16 miles in breadth, as in Tycho, Copernicus,
Kepler and Aristarchus. It is remarkable, however, that Galileo, in his
letter to Father Christoph Grienberger, SMe montuosita della Luna,
should have thought of comparing annular mountains, whose diameter
he considered greater than they actually are, to the circumvallated
district of Bohemia, and that the ingenious Robert Hooke in his
" Micrography " attributes the type of circular formation almost uni-
versally prevalent on the moon to the reaction of the interior of its
body on the exterior (vol. ii, p. 701, and vol. iv, p 496). With respect
to the annular mountain ranges of the moon, I have been of late much
interested with the relation between the height of the central mountain
and that of the circumvallation or margins of the crater, as well as by
the existence of parasitic craters on the circumvallation itself. The
result of all the careful observations of Julius Schmidt, who is occupied
with the continuation and completion of Lohrmami's Topography of
the Moon, establishes "that no single central-mountain attains the
height of the wall of its crater, but that in all cases it probably even
lies together with its summit considerably below that surface of the
inoon from which the crater is erupted. While the cone of ashes in the
crater of Vesuvius which rose on the 22nd of October 1822, according
to Brioschi's trigonometrical measurement, exceeds in height the Punta
del Palo, the highest edge of the crater on the north (618 toises above
the sea), by about 30 feet, and was visible at Naples, many of the
central mo'intains of the moon, measured by Madler and the Olmiitz
Astronomer, lie fully 6400 feet lower than the mean margin of cir
cumvallation, nay, even 100 toises below what may be taken as
t/ie mean surface-level in that part of the moon to which they respec«
tival belong {Madler, iu Schumacher s Jahrbuchfur 1841, pp. 272 aud

TRUE VOLCANOES. 449

If, as I would fain hope, what I here propound regarding
the classification of the volcanic rocks ; or, to speak more
precisely, on the arrangement of the trachytes according to
their composition, excites any particular interest, the merit
of this classification is entirely due to my friend and Sibe-
rian fellow-traveller, Gustav Rose. His accurate observa-
tion of nature, and the happy combination which he possesses

274, and Jul. Schmidt; Der Mond, 1856, s. 62). In general, the central
mountains, or central mountain-masses of the moon have several sum-
mits, as in Theophilus, Petavius and Bulliald. In Copernicus there are
6 central mountains, and Alphonsus alcyie exhibits a true central sharp
pointed peak. This state of things recalls to mind the Astroni in the
Phlegraean fields, on whose dome-formed central masses Leopold von
Buch justly lays much stress. " These masses," he says, " like those
in the centre of the annular mountains of the moon, did not break forth.
There existed no permanent connection with the interior, — no volcano,
but they rather appeared like models of the great trachytic unopened
domes so abundantly dispersed over the earth's crust, such as the Puy
de Dome and Chimborazo." (Poggendorffs Annalen, Bd. xxxvii, 1836,
p. 183.) The circumvallation of the Astroni is of an elliptic form, closed
all round, and rises in no part higher than 830 feet above the level of
the sea. The tops of the central summits lie more than 660 feet lower
than the maximum of the south-western wall of the crater. The sum-
mits form two parallel ridges, covered with thick bushes (Julius Schmidt,
Eruption des Vesuvs. s. 147, and Der Mond, s. 70 and 103). One of
the most remarkable objects, however, on the whole surface of the moon
is the annular mountain-range of Petavius, in which the whole internal
floor of the crater expands convexly in the form of a tumour or cupola,
and is crowned besides with a central mountain. The convexity here
is a permanent form. In our terrestrial volcanoes the flooring of the
crater is only temporarily raised by the force of internal vapours some-
times almost to the height of the margin of the crater, but as soon as
the vapours force their way through, the floor sinks down again. The
largest diameters of craters on the earth are,— the Caldeira de Fogo, ac-
cording to Charles Deville 4100 toises (4 '32 geogi-aphical miles) and the
Caldeira de Palma, according to Leop. v. Buch 3100 toises, while on
the moon, Theophilus is 50,000 toises, and Tycho 45,000 toises, or
respectively, 52 and 45 geogr. miles in diameter. Parasitic craters,
erupted from a marginal wall of the great crater, are of very frequent
occurrence on the moon. The base of these parasitic craters is usually
empty, as on the great rent margin of the Maurolycus ; sometimes, but
more rarely, a smaller central mountain, perhaps a cone of eruption, is
seen in them, as in Logomontauus. In a beautiful sketch of the
crater-system of Etna, which my friend Christian Peters the Astro-
nomer (now in Albany, North-America) sent me from Flensburg in
August 1854, the parasitic marginal crater, called the Pozzo di Fuoco,
which was formed in January 1833, on the east-south-east side, and
which had several violent eruptions of lava, is distinctly recognisable,
VOL. V. 2 G

4-50 COSMOS.

of chemical, crystal! o-mineralogical and geological knowledge,
have rendered him peculiarly well qualified to promulgate new
views on that set of minerals whose varied, but frequently
recurring association is the product of volcanic action. This
great geologist, partly at my instigation, has with the
greatest kindness, especially since the year 1834, repeatedly
examined the fragments which I brought from the slopes of
the volcanoes of New Granada, los Pastos, Quito, and the
high land of Mexico, and compared them with the spe-
cimens from other parts of the globe contained in the rich
mineral-collection of the Berlin Cabinet. Before my collec-
tions were separated from those of my companion Aime Bon-
pland, Leopold von Buch had examined them microscopically
with persevering diligence (in Paris, 1810 — 1811, between
his return from Norway and his voyage to Teneriffe). He
had also, at an earlier period, during my residence with Gay
Lussac at Rome (in the Summer of 1805) as well as after-
wards in France, made himself acquainted with what I had
noted down in my travelling journal on the spot, in the
month of July 1802, respecting certain volcanoes, and in
general on the affinity between volcanoes and certain porphy-
ries destitute of quartz66. I preserve as a memorial which I

6(3 The unspecific and indefinite term "trachyte" (Rauhstein), which
is now so generally applied to the rock in which the volcanoes break
out, was first given to a rock of Auvergne, in the year 1822 by Hauy in
the second edition of his Traite de Mineralogie, vol. iv, p. 579, with a
mere notice of the derivation of the word and a short description in
which the older appellations of granite chauffe en place of Desmarets),
trap-porphyry and domite are not even mentioned. It was only by
oral communication, originating in Hauy's Lectures in the Jardin des
Plantes, that the term " trachyte " was propagated previous to 1822, for
example, in Leopold von Buch's treatise on basaltic islands and craters
of upheaval, published iu 1818, in Daubuisson's Traite de Mineralogie,
1819, and in Beudant's important work, Voyage en Hongrie. From
letters lately received by me from M. Elie de Beaumont, I find that
the recollections of M. Delafosse, formerly Aide-Naturaliste to Hauy,
and now Member of the Institute, fix the application of the term " tra-
chyte " between the years 1813 and 1816. The publication of the term
"domite" by Leop. v. Buch, seems according to Ewald, to have occurred
in the year 1809; it is first mentioned in the third letter to Karsten
(Geognost. Beolaclit. auf Reisen durch Deutschl. undItalien,~Bd.u, 1809,
s. 244). " The porphyry of the Puy de Dome," it -is there stated, "is
a peculiar, and hitherto nameless rock, consisting of crystals of fel-
spar with a glassy lustre, hornblende and small laminse of black mica.
In the clefts of this kind of rock, which I provisionally term domite,

TRUE VOLCANOES. 451

consider invaluable, some sheets with remarks on the volcanic
products of the elevated plateaux of Quito and Mexico, which
the great geologist communicated to me for my information
more than 46 years ago. Travellers, as I have elsewhere17
said, being merely the bearers of the imperfect knowledge of

I find beautiful drusic cavities, the walls of which are covered with
crystals of iron-glance. Through the whole length of the Puy, cones
of dornite alternate with cones of cinders." The second volume of
the Travels, containing the letters from Auvergne, was printed in 1806,
but not published till 1809, so that the publication of the name of
domite properly belongs to the latter year. It is singular that four
years later, in Leopold von Buch's treatise on the trap-porphyry,
domite is not even mentioned. — In referring to a drawing of the pro-
file of the Cordilleras, contained in the journal of my travels in the
month of July 1802, and included between the 4th degree north and
4th degree south latitude under the inscription " Affinite' entre le feu
volcanique et les porphyres," my only object was to mention that this
profile, which represents the three breakings through of the volcanic
groups of Popayan, Los Pastos and Quito, as well as the eruption of
the trap-porphyry in the granite and mica-slate of the Paramo de
Assuay (on the great road from Cadlud, at a height of 15,526 feet),
led Leopold von Buch, too kindly and too distinctly, to ascribe to
me the merit of having first noticed " that all the volcanoes of the
chain of the Andes have their foundation in a porphyry which is a
peculiar kind of rock and belongs essentially to the volcanic forma-
tions" (Abhandlungen der ATchademie der Wissenscli. zu Berlin, aus den
Jahren, 1812—1813, s. 131, 151 and 153). I may indeed have noticed
the phenomenon in a general way, but it had already, as early as 1789,
been remarked by Nose, whose merits have long been too little appre-
ciated, in his Orographical Letters, that the volcanic rock of the Sie-
bengebirge is "a peculiarly Rhenish kind of porphyry, closely allied
to basalt and porphyritic schist." He says '* that this formation i.s
especially characterised by glassy felspar," which he proposes should
be called sanidine, and that it belongs, judging from the age of its
formation, to the middle floetz-rocks (Niederrheinische Rdse, Th. i,
s. 26, 28 and 47 ; Th. ii, s. 428). I do not find any grounds for
Leopold von Buch's conjecture that Nose considered this porphyry-
formation, which he not very happily terms granite-porphyry, as
well as the basalts, to be of later date than the most recent floetz-
rocks. " The whole of this rock," says the great geologist, so early
removed from among us, " should be named after the glassy felspars
(therefore sanidine-porphyry) had it not already received the name of
trap-porphyry" (Abh. der Berl. AJcad. aus den J. 1812—13, s. 134).
The history of the systematic nomenclature of a science is so far of
importance as the succession of prevalent opinions is found reflected
in it.

67 Humboldt, Kldnere ScJiriftcn, Bd. i, Vorrede, s. iii. — v,

2G2

452 COSMOS.

their age, and their observations being deficient in many of
the leading ideas, that is to say, those discriminating marks
which are the fruits of an advancing knowledge, the mate-
rials which have been carefully collected and geographically
arranged, will almost alone maintain an enduring value.

To confine the term trachyte, as is frequently done (on
account of its earliest application to the rocks of Auvergne
and of the Siebengebirge, near Bonn) to a volcanic rock con-
taining felspar, especially Werner's vitreous felspar, Nose's
and Abioh's sanidine, is fruitlessly to break asunder that in-
timate concatenation of volcanic rock which leads to higher
geological views. Such a limitation might justify the ex-
pression " that in Etna, so rich in labradorite, no trachyte
occurs." Indeed my own collections are said to prove that
" no single individual of the countless volcanoes of the Andes
consists of trachyte ; that in fact the subtance of which
they are composed is albite, and that therefore, as oligoclase
was at that time (1835) always erroneously considered to be
albite, all kinds of volcanic rock should be designated an-
desite (consisting of albite with a small quantity of horn-
blende)".68 Gustav Rose has taken the same view that I my-
self adopted, from the impressions which I brought back
with me from my journeys, on the common nature of all vol-
canoes, notwithstanding a mineralogical variation in their in-
ternal composition ; on the principle developed in his admi-
rable essay on the felspar groups,69 in his classification of
the trachytes, he generalizes orthoclase, sanidine, the anor-
thite of Mount Somma, albite, labradorite and oligoclase, as
forming the felspathic ingredient of the volcanic rocks.
Brief appellations which are supposed to contain definitions
lead to many obscurities in orology as well as in chemistry. I
was myself for a long time inclined to adopt the expressions
orthoclase-trachytes, or labrador-trachytes, or oligoclase-tra-

68L£op. v. Buch in Poggend, Annalen, Bd. xxxvii, 1836, s. 188, 190.

69 Gustav Rose in Gilbert's Annalen, Bd. Ixxiii, 1823, s. 173, and
Annales de Chimie et de Physique, t. xxiv, 1823, p. 16. Oligoclase was
first held by Breithaupt as a new mineral species (Poggendorff's Annalen,
Bd. viii, 1826, s. 238). It afterwards appeared that oligoclase was iden-
tical with a mineral which Berzelius had observed in a granite dyke
resting upon gneiss near Stockholm, and which, on account of the re-
semblance in ita chemical composition he had called '' Natron Spodu-
men." (Poggendorff's Annal. Bd. ix, 1827, s. 281).

TRUE VOLCANOES. ' 453

chyles, thus comprehending the glassy felspar (sanidine), on
account of its chemical composition, under the species ortho-
clase (common felspar). The terms were at least well-sound-
ing and simple, but their very simplicity must have induced
error, for though labrador-trachyte points to Etna and to
Stromboli, yet oligoclase-trachyte, in its important twofold
combination with augite and hornblende, would erroneously
connect the widely diffused and very dissimilar formations
of Chimborazo and the volcano of Toluca. It is the asso-
ciation of a felspathic element with one or two others which
here forms the characteristic feature, as it does in the forma-
tion of some mineral-dykes.

The following is a view of the divisions into which Gustav
Rose, subsequently to the winter of 1852, distributes the
trachytes, in reference to the crystals enclosed in them, and
separately recognisable. The chief results of this work, in
which there is no confounding of oligoclase with albite, were
obtained ten years earlier ; when my friend discovered, in
the course of his geognostic investigations in the Riesenge-
birge, that the oligoclase there formed an essential ingredient
of the granite, and his attention being thus directed to the
importance of oligoclase as an ingredient of that rock, he
was induced to look for it likewise in other rocks.70 This
examination led to the important result (Poggend. Ann.
Bd. Ixvi, 1845, s. 109) that albite never forms a part in the
mixed composition of any rock.

First division. " The principal mass contains only crystals
of glassy felspar, which are laminar, and in general large.
Hornblende and mica either do not occur in it at all, or in
extremely small quantity, and as an entirely unessential ad-
mixture. To this division belongs the trachyte of the Phle-
"° See Gustav Rose on the granite of the Riesengebirge, in Poggen-
dorff's Ann. Bd. Ivi, 1842, s. 617. Berzelius had found the oligoclase,
his " Natron Spodumen," only in a dyke of granite ; in the treatise just
cited it is for the first time spoken of as an ingredient in the composi-
tion of granite (the mineral itself). Gustav Rose here determined the
oligoclase according to its specific gravity, the greater proportion of
lime contained in it as compared with albite, and its greater fusibility.
The same compound with which he had found the specific gravity to
be 2.682 was analysed by Rammelsberg (Handworterbuch der Mineralog.
eupplem. i, s. 104, and G. Rose Ueber die zur Granitgruppe gehorenden
Gebirgsarten, in the Zeitschr. der Deutschen geol. Gesellschajt, Bd. i, 1849,
B. 364).

COSMOS.

grsean Fields (Monte Olibano near Pozzuoli), that of Ischia
and of La Tolfa, as also a part of tlie Mont-Dore (the Grande
Cascade). A ugite is but very rarely found in small crystals
in trachytes of the Mont-Dore71 — never, in the Phlegrsean
Fields together with hornblende ; nor is leucite, of which
last however, Hoffmann collected some pieces on the Lago
Averno (on the road to Cuinse), while I found some on the
slope of the Monte Nuovo72 (in the autumn of 1822).
Leucite-ophyr in loose fragments is more frequent in the
island of Procida and the adjoining Scoglio di S. Martino."

Second Division. " The ground-mass contains some de-
tached crystals of glassy felspar, and a profusion of small
snow-white crystals of oligoclase. The latter are frequently
overspread with the glassy felspar in regular order, and
form a covering about the felspar, as is so frequently seen
in G. Hose's granitite (the principal mass of the Eiesen-
gebirge and Iser-gebirge, consisting of granite with red
felspar, particularly rich in oligoclase and magnesian-mica,
but without any white potash-mica). Hornblende and mica,
and in some modifications augite, occasionally appear in
small quantity. To this division belong the trachytes of the
Drachenfels and of the Perlenhardt in the Siebengebirge73
near Bonn, and many modifications of the Mont-Dore and
Cantal ; some trachytes also of Asia Minor (for which we
are indebted to that industrious traveller Peter von Tschi-

71 Eozet, Sur les montagnes de 1'Auvergne, in the Mem. de la Soc.
Geol.de France, 2me SeVie, t. i, partie i, 1844, p. 69.

72 Fragments of Leucite-ophyr, collected by me at the Monte Nuovo,
are described by Gustav Hose in Fried. Hoffmann's Geoynosticheii Beo-
backtungen, 1839, s. 219. On the trachyte of the Monte di Procida of
the island of the same name, and the rock of San Martino, see Roth,
Monographic des Vesuvs. 1857, s. 519 — 522, tab. viii. — The trachyte of
the island of Ischia contains in the Arso, or stream of Cremate (1301)
vitreous felspar, brown mica, green augite, magnetic iron and olivine
(s. 528), but no leucite.

73 The geologico-topographical conditions of the Siebengebirge near
Bonn, have been developed with comprehensive talent and great exact-
ness by my friend H. von Dechen, director of mines, in the 9th annual
volume of the Verhandlungcn des Naturhistorischen Vereines der Preuss,
RkcMandeund Westphalens, 1852, s. 289—567. All the chemical ana-
lyses of the trachytes of the Siebengebirge which hf>ve hitherto ap-
peared are there collected (p. 323 — 356); mention is also made of the
trachytes of the Drachenfels and Rottchen, in which, besides the large
crystals of sanidine, several small crystalline particles may be distm-

TRUE VOLCANOES. 455

ehatscheff), of Afran Karahissar (famous for the culture of the
poppy) and Menammed-kyoe in Phrygia, and of Kayadschyk
and Donanlar in Mysia, in which glassy felspar, with a great
deal of oligoclase, some hornblende, and brown mica are
mingled."

guisbed in the fundamental mass. " These portions have been found
by I)r. Bothe, on chemical analysis in Mitscherlich's Laboratory, to
be oligoclase, corresponding exactly with the oligoclase of Danvikszoll
(near Stockholm) noticed by Berzelius." (Dechen, s. 340 — 346). The
Wolkenburg and the Stenzelberg are destitute of glassy felspar (s. 357
and 363), and belong, not to the second division, but to the third ; they
contain a Toluca-rock. That section of the geological description of
the Siebengebirge which treats of the relative age of trachyte-conglo-
merate and basalt conglomerate contains many new views (p. 405 — 461).
" With the more rare dykes of trachyte in the trachyte-conglomerates,
which prove that the formation of trachyte has still continued after the
deposit of the conglomerate (s. 413), are associated a great number of
basalt courses (s. 416). The basalt-formation extends decidedly into a
later basalt than the trachyte-formation, and the principal mass of the
basalt is here more recent than the trachyte. On the other hand a portion
of this basalt only, and not of all basalts (s. 323) is more recent than the
great mass of the brown-coal rocks. Both formations, the basalt and
the brown-coal rocks, run into each other in the Siebengebirge as well
as in many other places, and must be considered in the aggregate as
contemporaneous." Where very small crystals of quartz occur by
way of rarity in the trachytes of the Siebengebirge, as (according
to Noggerath and Bischof) in the Drachenfels and in the valley of
Rhondorf, they fill up cavities and seem to be of later formation (p. 361
and 370) ; caused perhaps by efflorescence of the sanidiue. On Chim-
borazo I have on one solitary occasion seen similar deposits of quartz,
though very thin, on the internal surfaces of the cavities of some very
porous, brick-red masses of trachyte at an elevation of about 17,000
feet (Humboldt, Gisement des Roches, 1823, p. 336). These fragments,
which are frequently mentioned in my journal, are not deposited in the
Berlin collections. Efflorescence of oligoclase, or of the whole funda-
mental mass of the rock may also yield such traces of disengaged silicic
acid. Some points of the Siebengebirge still merit renewed and perse-
vering investigation. The highest summit, the Lowenburg, represented
as basalt, seems, from the analysis of Bischof and Kjerulf, to be a do-
leritic rock (H. v. Dechen, s. 383, 386, 393). The rock of the little
Rosenau, which has sometimes been called Sanido-phyre, belongs, ac-
cording to G. Rose, to the first division of his trachytes, and is very
closely allied to many of the trachytes of the Ponga Islands. The
trachyte of the Drachenfels with large crystals of glassy felspar seems,
according to Abich's yet unpublished investigations, most nearly to
resemble the Dsyndserly-dagh which rises to a height of 8526 feet, to
the north of the great Ararat, from a formation of iiummulites under-
dipped by Devonian strata.

456 COSMOS.

Third Division. "The ground-mass of this dioritic tra-
chyte contains many small crystals of oligoclase with black
hornblende and brown magnesian-mica. To this belong
the trachytes of ^gina,74 of the valley of Kozelnik near
Schemnitz75, of Nagyag in Transylvania, of Montabaur in
the Duchy of Nassau, of the Stenzelberg and the Wolken-
biirg in the Siabengebirge near Bonn, of the Puy de Chau-
mout, near Clermont in Auvergne, and of the Liorant in
Cantal; also the Kasbegk in the Caucasus, the Mexican vol-
canoes of Toluca76 and Orizaba, the volcano of Purace and the
splendid columns of Pisoje77 near Popayan, though whether
the latter are trachytes is very uncertain. The domites
of Leopold von Buch belong likewise to this third di-
vision. In the white, fine-grained fundamental mass of
the trachytes of the Puy de Dome are found glassy crys-
tals, which were constantly taken for felspar, but which are
always streaked on the most distinct cleavage surface, and
are oligoclase ; hornblende and some mica are also present.
Judging from the volcanic specimens for which the royal

74 From the close propinquity of Cape Perdica of the island of
JEgma, to the long famous red-brown Trozen-trachytes (Cosmos, see
above, p. 229) of the peninsula of Methana, and from the sulphur-
springs of Bromolimni, it is probable that the trachytes of Methana, as
well as those of the island of Kalauria, near the small town of Poros,
belong to the same third division of Gustav Rose (oligoclase with
hornblende and inica) (Curtius, Peloponnesos, Bd. ii, s. 439, 446,
tab. xiv).

75 See the admirable geological map of the district of Schemnitz by
Bergrath, Johann von Peltko, 1852, and the Abhandlungen dtr Jc. k.
yeologischen Reichsanstalt, Bd. ii, 1855, Abth. i, s. 3.

76 Cosmos, see above, pp. 401 — 2.

77 The basaltic columns of Pisoje, the felspathic part of which has been
analysed by Francis (Poggend. Annal. Bd. lii, 1841, s. 471), near the

banks of the Cauca, in the plain of Amolanga (not far from the Pueblos
of Sta. Barbara and Marmato), consist of a somewhat modified oligo-
clase in large beautiful crystals, and small crystals of hornblende.
Nearly allied to this mixture are, the quartz, containing dioritic-por-
phyry of Marmato, brought home by Degenhardt, the felspathic part of
which was named by Abich Andesine, — the rock, destitute of quartz,
of Cucurusape, near Marmato, in Boussingault's collection (Charles
Ste.-Cl. Deville, Etudes de Lithologie, p. 29), the rock which I found 12
geographical miles eastward of Chimborazo, below the ruins of old
lliobamba (Humboldt, Kleinere Scliriften, Bd. i, s. 161), and lastly, the
rock of the Esterel Mountains in the department of the Var (Elie da
Beaumont, Explic. de la, Carte Geol. de France, t. i, p. 473).

TRUE VOLCANOES. 457

collection is indebted to Herr Mollhausen, the draughtsman
and topographist of Lieut. Whipple's exploring expedition,
the third division, or that of the dioritic Toluca-trachytes,
also includes those of Mount Taylor, between Santa Fe del
Nuevo Mexico and Albuquerque, as well as those of Ciene-
guilla on the western slope of the Rocky Mountains, where,
according to the able observations of Jules Marcou, black lava-
streams overflow the Jura-formation." The same mixture of
oligoclase and hornblende which I saw in the Azteck high-
lands, in Anahuac proper, but not in the Cordilleras of South
America, are also found far to the west of the Rocky Moun-
tains and of Zuni, near the Mohave river, a tributary of the Rio
Colorado (see Marcou, Resume of a geological reconnaissance
from the Arkansas to California, July, 1854, pp. 46 — 48. See
also two important French treatises, — Resume explicatif d* une
Carte Geologique des Etats-Unis, 1855, pp. 113 — 116, and Ex-
quisse d une Classification des Chames de J&Lontaqnes de T A.me-
rique du Nord, 1855 ; Sierra de S. Francisco et Mount Taylor,
p. 23). Among the trachytes cf Java, for specimer „ of which
I am indebted to my friend Dr. Junghuhn, we have likewise
recognised those of the third division in three volcanic dis-
tricts, namely, Burung-agung, Tyinas and Gurung Parang
(in the Batugangi district).

Fourth division. " The leading mass contains augite with
oligoclase : — the Peak of Teixcrilie,78 the Mexican volcanoes

"8 The felspar in the trachytes of Teneriffe was first recognised in
1842 by Charles Deville, who visited the Canaiy Islands in the autumn
of that year ; see that distinguished geologist's Voyage Geologique aux
Antilles et aux lies de Teneriffe et de Fogo, 1848, pp. 14, 74, and 169 ;
also Analyse du Feldspath de Te'neriffe, in the Comptes rendus deVAcad.
des Sciences, t. xix, 1844, p. 46. " The labours of Messrs. Gustav Rose
and H. Abich," he says, " have contributed in no small degree, both
crystallographically and chemically, to throw light on the numerous
varieties of minerals which were comprised under the vague denomina-
tion of felspar. I have succeeded in submitting to analysis carefully
isolated crystals whose density in different specimens was very uni-
formly 2-593, 2-594, and 2'586. This is the first time that the oligo-
clase felspar has been indicated in volcanic regions, with the excep-
tion perhaps of some of the great masses of the Cordillera of the
Andes. It was not detected, at least with any certainty, except in the
ancient eruptive rocks (plutouic, granite, syenite, syenitic porphyry
), but in the trachytes of the Peak of Teneriffe it plays a
part analogous to that of the labrador in the doleritic masses of

458 COSMOS.

Popocatepetl79 and Colima, the South American volcanoes,
Tolima (with the Paranio de Ruiz), Purace near Popayan,

Etna." Compare also Rammelsberg, in the Zeitschr. der Deutscken
geol. Gesettschaft, Bd. v, 1853, s. 691, and the 4th Supplement of
his ffandwb'rterbuchs der chem. Mineralogie, s. 245.

5-9 The first determination of height of the great volcano of Mexico,
Popocatepetl is, so far as I am aware, the trigonometrical measure-
ment already mentioned (see above, p. 41, note 42), executed by me on
24th January, 1804, in the Llano de Tetimba. The summit was found
to be 1536 toises above the Llano, and as the latter lies barometrically
1234 toises above the coast of Vera Cruz, we obtain 2770 toises, or
17.728 English feet, as the absolute height of the volcano. The baro-
metrical mersurements which have succeeded my trigonometrical cal-
culation lead me to conjecture that the volcano is still higher than I
have made it in the Essai sur la Geographic des Plantes, 1807, p. 148,
and in the Essai Politique sur la Nouv. Espagne, t. i, 1825, p. 185.
William Glennie, who first reached the margin of the crater on the
20th April, 1827, found it, according to his own calculation (Gazcta
del Sol, published in Mexico, No. 1432), 17,884 feet, equal to 2796
toises, but, as corrected by the mining director, Burkart, who has
acquired so high a reputation in the department of American hypso-
metry, and who compared the calculation in Vera Cruz with barome-
trical observations taken nearly at the same time, it cornea out
fully 18,017 feet. On the other hand, a barometrical measurement
by Samuel Birbeck (10th Nov. 1827), calculated according to the tables
of Oltmanns, gave only 17,854 feet, and the measurement of Alex.
Doignon (Gumprecht, Zeitsclirift fur Allg. Erdkunde, Bd. iv, 1855,
s. 390) ; coinciding almost too precisely with the trigonometrical
measurement of Tetimba, gives 5403 metres, equal to 17,726 feet.
The talented Herr von Gerolt, the present Prussian ambassador in
Washington, accompanied by Baron Gros, likewise visited the sum-
mit of Popocatepetl ^2Sth May, 1833), and found, by an exact barome-
trical measurement, the Roca del Fraile, below the crater, 16,896 feet
above the sea. Singularly contrasted with these chronologically-stated
hypsometrical results appears a carefully-conducted barometrical mea-
surement by M. Craveri, published by Petermann in his valuable
Mittheilungen iiber wiclitige neue Erforschungen der Geographic, 1856
(Heft x), s. 358—361. That traveller found, in September, 1855, the
height of the highest margin of the crater, the north-west, compared
with what he considered the mean height of the atmospheric pressure
in Vera Cruz, only 5230 metres, or 17,159 feet, which is 555
feet (£% of the whole height under measurement) less than I
found it by trigonometrical measurement half a century previous.
Craveri likewise makes the height of the city of Mexico above the sea
.196 feet less than Burkart and I have found it to be at very different
times ; he reckons it at only 2217 metres, or 7274 feet, instead of
2277 metres, or 7471 feet. In Dr. Petermann's periodical above
reierred to, p. 479 — 481, I have explained myself more particularly on

TRUE VOLCANOES. 459

Pasto and Cumbal (according to specimens collected by

the subject of these variations plus or minus, as compared with the
result of my trigonometrical measurement, which unfortunately has
never been repeated. The 453 determinations of height which I made
from September, 1799, to February, 1804, in Venezuela, on the woody
shores of the Orinoco, the Rio de la Magdalena, and the river Amazon ;
in the Cordilleras of New Granada, Quito, and Peru, and in the tropical
region of Mexico, all of which, re-calculated by Professor Oltmanns,
uniformly according to the formula of Laplace and the co-efficients
of Ramond, have been published in my Nivelkment JSarometrique et Geo-
logique, 1810 (Recueil d'Olserv. Astronom. t. i, pp. 295—334) were^ per-
formed without exception with Ramsden's cistern-barometers "a niveau
constant," and not with apparatus in which several fresh-filled Torricel-
lian tubes may be inserted one after another, nor by the instrument, pro-
jected by myself, described in Lametherie's Journal de Physique, t. iv,
p. 468, and occasionally used in Germany and France during the years
1796 and 1797. Gay-Lussan and I made use, to our mutual satisfaction,
of a portable Ramsden cistern-barometer exactly similar in construc-
tion, in the year 1805, during our journey through Italy and Swit-
zerland. The admirable observations of the Olmutz astronomer,
Julius Schmidt, on the margins of the crater of Vesuvius (Beschreib un y
der Eruption im Mai, 1855, s. 114 — 116) furnish from their similarity
additional motives of satisfaction. As I never have ascended the sum-
mit of Popocatepetl, but measured it trigonometrically, there is no
foundation whatever for the extraordinary criticism (Craven, in Peter-
maun's Geogr. Mittheilungen, Heft x, s. 359), " that the height of the
mountain as described by me is unsatisfactory, because, as I my-
self stated, I had made use of fresh-filled Torricellian tubes." The
apparatus with several tubes ought never to be used in the open air,
more especially on the summit of a mountain. It is one of those
means which, from the conveniences furnished by large towns, may
be employed at long intervals, when the opeiator feels anxious as to
the state of his barometer. For my own part, I have had recourse to
it only on very rare occasions, but I would nevertheless still recom-
mend it to travellers, accompanied by a comparison with the boiling
point, as warmly as I did in my Observations Astronomiques (vol. i,
pp. 363 — 373): — "As it is better not to observe at all than to make bad
observations, we ought to be less afraid of breaking the barometer than
of putting it out of order. M. Bonpland and I having four different
times traversed the Cordilleras of the Andes, the determinations which
chiefly interested us were repeated at different times, as we returned
to the places which seemed doubtful. We occasionally employed the
apparatus of Mutis, in which Torricelli's primary experiment is per-
formed, by applying- successively three or four strongly heated tubeK,
filled with mercury recently boiled in a stoneware crucible. When
there is no possibility of replacing the tubes, it is perhaps prudent
not to boil the mercury in the tubes themselves. In this way
I have found, in experiments made in conjunction with Lindner,

iGO COSMOS.

Boussingault), Rucu-Piehincha, Antisana, Cotopaxi, Chim-

Professor of Chemistry at the School of Mines in Mexico, the height of
the column of mercury at Mexico in six tubes, as follows :—

259.7 lines (old Paris foot)

259.5

259.9

259.9

260.0

259.9

" The two last tubes alone had, by means of heat, been deprived of air
by Bellardoni, the instrument maker at Mexico. As the exactness of
the experiment depends partly on the perfect cleanliness of the inside
of the empty tubes, which are so easily carried, it is a good plan to seal
them hermetically over a lamp." As the angles of altitude cannot, in
mountainous districts, be taken from the sea-shore, and the trigono-
metrical measurements are of a mixed nature and to a considerable
extent (frequently as much as i or -^y of the whole height) baro-
metrical, the determination of the height of the elevated plain in which
the base line may be measured is of great importance. As cor-
responding barometrical observations at sea are seldom obtained, or for
the most part only at too great a distance, travellers are too often in-
duced to take the results they have obtained from a few days' obser-
vations, conducted by them at different seasons of the year, as the
mean height of the pressure of the atmosphere on the elevated plain
and at the seashore. u In wishing to know whether a measurement
made by means of the barometer possesses the exactness of trigono-
metrical operations, it is only necessary to ascertain whether, in a given
case, the two kinds of measurement have been taken under equally
favourable circumstances, that is to say, by fulfilling those con-
ditions which both theory and long experience have prescribed. The
mathematical experimenter dreads the effect of terrestrial refrac-
tions, while the physical experimenter has reason to fear the
unequal and far from simultaneous distribution of the temperature
in the column of air at the extremities of which the two barometers
are placed. It is probable enough that near the surface of the earth
the decrease of caloric is slower than at greater elevations, and in
order to ascertain with precision the mean density of the whole column
of air, it would be necessary to ascend in a balloon so as to examine the
temperature of each successive stratum or layer of the superimposed
air" (Humboldt, Recueil d' Observ. Astron. vol. i, p. 138; see also 371, in
the appendix on refraction and barometrical measurements). While
the barometrical measurement of M. M. Truqui and Craveri gives only
17,159 feet to the summit of Popocatepetl, whereas Glennie gives
17,889 feet, I find that the lately published measurement of Professor
Carl Heller of Olmiitz, who has thoroughly investigated the district
surrounding Mexico, as well as the provinces of Yucatan and Chiapa,

TRUE VOLCANOES. 461

borazo,80 Tunguragua, and trachyte rocks which are
covered by the ruins of Old Riobamba. In the Tunguragiia,
besides the augites there occur also separate blackish green

corresponds to within 32 feet of my own. (Compare my Essay on th«
If eight of the Mexican Volcano Popocatepetl, in Dr. Petermann's
Mittheilungen aus Justus Perthes Geographischer Anstalt, 1856, s. 479
—481).

80 In the Chimborazo rock it is not possible, as in the Etna rock,
to separate mechanically the felspathic crystals from the ground-
mass in which they lie, but the large proportion of silicic acid which
it contains, along with the fact connected therewith of the small
specific gravity of the rock, make it apparent that the felspathic
constituent is oligoclase. The quantity of silicic acid which a mineral
contains and its specific gravity are generally in an inverse ratio ;
in oligoclase and labradorite the former is 64 and 53 per cent,
while the latter is 2.66 and 2.71. Anorthite, with only 44 per cent, of
silicic acid, has the great specific gravity of 2.76. This inverse pro-
portion between the quantity of silicic acid and the specific gravity
does not occur, as Gustav Rose remarks, in the felspathic minerals,
which are also isomorphous, but with a different crystalline form.
Thus felspar and leucite, for instance, have the same component
parts, — potash, alumina, and silicic acid. The felspar, however, con-
tains 65 and the leucite only 56 per cent, of silicic acid, yet the
former has a higher specific gravity, namely, 2.56, than the latter,
whose specific gravity is only 2.48.

Being desirous in the spring of 1854 to obtain a fresh analysis of
the trachyte of Chimborazo, Professor Rammelsberg kindly undertook
the task, and performed it with his usual accuracy. I here give the
results of this analysis, as they were communicated to me by Gustav
Hose, in a letter in the month of June, 1854. He says : " The Chim«
borazo rock, submitted to a careful analysis by Professor Rammels-
berg, was broken from a specimen belonging to your collection, which
you had brought home from the narrow rocky ridge at a height of
more than 19,000 feet above the sea."

Rammelsberys Analysis.
(Height 19,194 English feet; spec. grav. 2.806.)

Oxygen.

Silicic acid 59.12 ... 30.70 2.33

Alumina 13.48 ... 6.30

Protoxide of irou 7.27

Lime (5.50

Magnesia 5.41 2.13} T.93

Soda ...... 3.46

Potash 2.64

97.83

V.fU ^.O<

6.30 j ...
6.93 J

462 COSMOS.

crystals of uralite, of from half a line to five lines in length,
with a perfect augite form and the cleavage of hornblende
(see Rose, Reise nacJi dem Ural, Bd. ii, s. 353)." I brought

Alick's Analysis.

(Height 16,179 English feet; spec. grav. 2.685.)

Oxygen.

Silicic acid 65.09 ... 33.81 . 2.63

Alumina 15.58 ... 7.27

Oxide of iron 3.83 ... 1.16

Protoxide 1.73 ... 0.39

Lime 2.61 ... 0.73

Magnesia 4.10 ... 1.58

Soda 4.46 ... 1.14

Potash 1.99 ... 0.33

Chlorine, and loss by ) «...
heat J

99.80

In explanation of these figures it must be observed, that the first
series gives the ingredients in a per eentage, the second and third give
the oxygen contained in them. The second space shows only the
oxygen of the stronger oxides (those which contain 1 atom of oxygen).
In the third space this is recapitulated, so as to offer a comparison
with that of the alumina earth (which is a weak oxide) and of the
silicic acid. The fourth space gives the proportion of the oxygen of
the silicic acid to the oxygen of the aggregate bases, which latter
are fixed = 1. In the trachyte of Chimborazo thia proportion
is -2.33:1.

" The differences between the analyses of Rarnmelsberg and of
Abich are certainly important. Both analysed minerals from Chim-
borazo, from the relative heights of 19,194 and 16,179 feet, which
wei'e broken off by you and were taken from your geological collection
in the Royal Mineral Cabinet at Berlin. The mineral from the lower
elevation (scarcely 400 feet higher than the summit of Mont Blanc)
which Abich has analysed, posseses a smaller specific gravity, and in
correspondence therewith a greater quantity of silicic acid, than the
mineral taken from a point 2918 feet higher, analysed by Ram-
nielsberg. Assuming that the argillaceous earth belongs only to the
felspathic ingredient, we may reckon in the analysis of Rammels-
berg :—

Oligoclase 58.66

Augite 34.14

Silicic acid 4.08

As thus, by the assumption of oligoclase, a portion of silicic acid
remains over uncombined, it is probable that the felspathic ingredient
is oligoclase and not labradorite. The latter does not occur witb

TRUE VOLCANOES.

463

a similar fragment, with distinct uralite crystals, from tlie
slope of the Tunguragua at an elevation of 13,260 feet.
Gustav Hose considers this specimen strikingly different

uncouibined silicic acid, and if we were to suppose labradorite in the
rock, a greater quantity of silicic acid would remain over."

A careful comparison of several analyses for which I am indebted
to the friendship of M. Charles Sainte-Claire Deville, to whom the
valuable geological collections of our mutual friend Boussingault are
accessible for chemical experiment, shows that the quantity of silicic
acid contained in the fundamental mass of the trachytic rocks is gene-
rally greater than in the felspars which they contain. The table kindly
communicated to me by the compiler himself in the month of June,
1857, contains only five of the great volcanoes of the chain of the
Andes : — '

Nnmes of
the Volcanoes.

Structure and Colour of the Mass.

Silicic Acid
in the whole Mass.

."232

*1!

£~ 3
i».S *

Chimborazo

; semi-vitrified, brownish grey
j semi-vitreous, and black
i crystalline, compact, grey
J grey-black

Go. 09 Abich }
63.19 Deville I
62.66 Deville )
64 26 Abich i

58.26

Antisana

63 23 Abich j

58.26

J vitreous and brownish

69 28 Abich )

Cotopaxi

63 98 Abich j

Pichincha

black, vitreous

67 07 Abich

Puracd

nearly bottle green

68.80 Deville

55 40

Guadaloupe
Bourbon

grey, granulated, and cellular
crystalline, grey, porous

57.95 Deville
50.90 Deville

54.25
49.06

" These differences, as far as regards the relative richness in silica of
the ground-mass (and the felspar)," continues Charles Deville, " will
appear still more striking when it is considered that, in analysing a,
rock en masse, there are included in the analysis, along with the basis
properly so called, not only fragments of felspar similar to those which
have been extracted, but even such minerals as amphibole, pyroxene,
and especially peridote, which are less rich in silica than the felspar.
This excess of silica manifests itself sometimes by the presence of iso-
lated grains of quartz, which M. Abich has detected in the trachytes
of the Drachenfels (Siebengebirge, near Bonn), and which I have myself
observed with some surprise in the trachytic dolerite of Guadaloupe."

" If," observes Gustav Rose, " we add to this remarkable synopsis of
the silicic acid contained in Chimborazo the result of the latest analysis,

cosmos.

from the seven fragments of trachyte from the same volcano
which are contained in my cabinet. It recalls to mind the
formation of green slate (schistose augitic-porphyry) which we

that of Rammelsberg in May, 1854, we shall find that the result
obtained by Deville occupies exactly the mean between those of Abich
and Rammelsberg. Thus : —

Cliimborazo-rock.

Silicic acid 65.09 Abich (spec. grav. 2.685)
63.19 Deville
62.66 do.
59.12 Rammelsberg (spec. grav. 2.806)"

In the Echo du Patifique of the 5th January, 1857, published at
San Francisco in California, an account is given of a French traveller,
named M. Jules Re"my, having succeeded, on the 3rd November, 1856,
in company with an Englishman, Mr. Brencklay, in reaching the
summit of Chimborazo, which was " however, enveloped in a cloud, so
that we ascended without perceiving it." He observed, it is stated,
the boiling point of water at 171°.5 F., with the temperature of the
air at 31°.9 F., on calculating upon these data, the height he
had attained by a hypsometrical rule tested by him in repeated
journeys in the Haway Archipelago, he was astonished at the result
brought out. He found, in fact, that he was at an elevation of 21,467
feet, that is to say, at a height differing by only 40 feet from that
given by my trigonometrical measurement at Riobamba Nuevo in the
elevated plain of Tapia, in June, 1803, as the height of the summit
of Chimborazo, — namely, 21,426 feet. This correspondence of a trigo-
nometrical measurement of the summit with one founded on the
boiling point is the more surprising, as my trigonometrical measure-
ment, like all measurements of mountains in the Cordilleras, involves
a barometrical portion, and from the want of corresponding observa-
tions on the shore of the South Sea, my barometrical determination of
the height of the Llano de Tapia, 9484 feet, cannct possess all the
exactness that could be desired. (For the details of my trigonometrical
measurement, see my Recueil d' Observations Aslron., vol. i, pp. 72 aud
74). Professor Poggendorff kindly undertook to ascertain what result
under the most probable hypotheses a rational mode of calculation
would produce. He found, reckoning under both hypotheses, that
the prevailing temperature of the atmosphere at the sea being 81C.5 F.,
or 79°.7 F., and the barometer marking 29.922 inches, with the ther-
mometer at the freezing point, the following result is obtained by
Regnault's table : — the boiling point at the summit at 171°.5 F. answers
to 12,677 inches of the barometer at 32° temperature ; the tempera-
ture of the air may therefore be taken at 35°.3 F. = 34°.7 F.
According to these data, Oltmanns' tables give, for the height ascended,
under the first hypothesis (81°.5), = 7328'".2, or 24,043 feet, and under
the second (79°.7), = 7314m.5, or 23,998 English feet, showing an

TRUE VOLCANOES. 4G5

have found so diffused on the Asiatic side of the Ural
(Ibid. s. 544).

Fifth division. " A mixture of labradorite81 and augite,*3
a doleritic trachyte : Etna, Stromboli ; and, according to
the admirable works on the trachytes of the Antilles by
Charles Saint e-Claire Deville, the Soufriere de la Guadeloupe,
as well as the three great cirques which surround the Pic de
Salazu, on Bourbon."

Sixth division. "The ground-mass, often of a grey
colour, in which crystals of leucite and augite lie imbedded,
with very little olivine : — Vesuvius and Sornma ; also the
extinct volcanoes of Yultur, Kocca Monfina, the Albanian
hills and Borghetto. In the older mass (for example, in the
wall and paving-stones of Pompeii) the crystals of leucite are
more considerable in size and more numerous than the augite.

average of 777m., or 2549 English feet, more than my barometrical
measurement. To have corresponded with this, the boiling point,
should have been found about 2°.25 cent, higher, if the summit of
Chimborazo bad actually been reached. Poggendorffs Annalen, Bd. c,
1857, s. 479.

bl That the trachytic rocks of Etna contain labradorite was demon •
strated by Gustav Rose in 1833, when he exhibited to his friends the rich
Sicilian collections of Friedrich Hoffmann in the Berlin Mineralogical
cabinet. In his treatise on the minerals known by the names of green-
stone and green-stone porphyry (Poggend. Annal., Bd. xxxiv, 1835,
p. 29), Gustav Rose mentions the lavas of Etna, which contain augite
and labradorite (compare Abich in his interesting treatise on the whole
felspathic-family, (Poggend. Annul., 1840, Bd. 1, s. 347). Leopold von
Buch describes the rock of Etna as analogous to the dolerite of the
basalt-formation (Poggend. Annal., Bd. xxxvii, 1836, s. 188).

82 Sartorius von Waltershausen, who has for many years carefully
investigated the trachytes of Etna, makes the following important
observations : — " the hornblende there belongs especially to the older
masses, — the green-stone veins in the Val del Bove, as well as the
white and red trachytes, which form the ground mass of Etna in
the Serra Giannicola. Black hornblende and bright yellowish-green
augite are there found side by side. The more recent lava-streams
from 1669 (especially those of 1787, 1809, 1811, 1819, 1832, 1838,
and 1842), show angiie, but no hornblende. The latter seems to be
generated only after a longer period of cooling'' (Waltershausen, Ueber
die vulkainscken Getteine ron SiciUen und Island, 1853, s. Ill — 114).
Ill the augitiferous trachytes of the fourth division in the chain of the
Andes, along with the abundant augites, I have indeed sometimes found
none, but sometimes, as at Cotopaxi (at an elevation of 14,068 feet) and
at Rucu-Pichincha, at a height of 15,304 feet, distinct black hornblende-
crystals in small quantities.

VOL. V. 2 H

46(5 COSMOS.

In the present lavas, on the contrary, the atigites predomi-
nate and the leucites are on the whole very scarce, although
the lava-stream of the 2 2nd April, 1845, has furnished them
in abundance.83 Fragments of trachytes of the first division,
containing glassy felspar (Leopold von Buch's trachyte
proper), are imbedded in the tufas of Monte Sornma ; they
also occur detached in the layer of pumice which covers
Pompeii. The leucite-ophyr- trachytes of the sixth division
must be carefully distinguished from the trachytes of the
first division, although leucites occur in the westernmost
part of the Phlegraean fields and on the island of Procida,
as has been already mentioned."

The talented originator of the above classification of vol-
canoes, according to the association of the simple minerals
which they present, does not by any means suppose that he
has completed the grouping of all that are found on the
surface of the earth, which is still on the whole so very

83 See Pilla, in the Compfes rendus de VAcad. des Sc., t. xx, 1845,
p. 324. In the leucite-crystals of the Rocca Monfina, Pilla has found
the surface covered with worm-tubes (scrpulcu), indicating a submarine
volcanic formation. On the leucite of the Eifel, in the trachyte of the
Burgberg near Riedeu, and that of Albano, Lago Bracciano, and Bor-
ghetto, to the north of Rome, see above, page 32, note 93. In
the centre of large crystals of leucite, Leop. v. Buch has generally
found the fi-agment of a crystal of augite, round which the leucite-
crystallisation has formed, " a circumstance which, considering the
ready fusibility of the augite, and the infusibility of the leucite, is
somewhat singular. More frequently still are fragments of the funda-
mental mass itself enclosed like a nucleus iu leucite-porphyry." Olivine
is likewise found in lavas, as in the cavities of the obsidian, which I
brought from the Cerro del Jacal in Mexico (Cosmos, vol. i, p. 268,
note J), and yet, strange to say, also in the hypersthene rock of
Elfdal (Berzelius, Sechster Jahrexbericht, 1827, s. 302), which was
long considered to be syenite. A similar contrast in the nature of the
places where it is found is exhibited by oligoclase, which occurs in the
trachytes of still burning volcanoes (the Peak of Teneriffe and Cotopaxi),
and yet at the same time also in the granite and granitite of Schreiber-
FHU and Warmbrunn in the Silesian Riesengebirge (Gustav Rose, in
the minerals belonging to the granite-group, in the Zeitscliriften d.
Deutsch. geoL Geselhch., zu Berlin, Bd. i, s. 364). This is not the case
with the leucite in the Plutonic rocks, for the statement that leucite
has been found disseminated in the mica-slate and gneiss of the
Pyrenees near Gavarnie (an assertion which even Hauy has repeated)
lias been found erroneous, after many years' investigation, by Dufreuoy
(Traits de Mincralogie, t. iii, p. 399).

TRUE VOLCANOES. 467

imperfectly investigated in a scientifically geological and
chemical sense. Modifications in the nomenclature of the
associated minerals, as well as additions to the trachyte-
formations themselves, are to be expected in two ways, both
from the progressive improvement of mineralogy itself (in a
more exact specific distinction both with regard to form and
chemical composition), and from the increased number of
collections, which are for the most part so incomplete and
so aimless. Here, as in all other cases where the governing
law in cosmical investigations can only be discovered by a
widely-extended comparison of individual cases, we must
proceed on the principle that everything which, in the
present condition of science, we think we know, is but a
small portion of what the next century will bring to light.
The means of early acquiring this advantage lie in profusion
before us, but the investigation of the trachytic portion of
the dry surface of the earth, whether raised, depressed, or
opened up by fissures, has hitherto been very deficient in the
employment of thoroughly exhaustive methods.

Though similar in form, in the construction of their frame-
work and their geotectonic relations, volcanoes situated
very near each other have frequently a very different indi-
vidual character in regard to the composition and association
of their mineral aggregate. On the great transverse fissure
which, extending from sea to sea, almost entirely in a direc-
tion from west to east, intersects a chain of mountains, or,
more properly speaking, an uninterrupted mountainous swell,
running from south-east to north-west, the volcanoes occur
in the following order :-— Colima (13,003 feet), Jorullo (4265
feet), Toluca (15168 feet), Popocatepetl (17,726 feet), and
Orizaba (17,884 feet). Those situated nearest to each other
are dissimilar in the composition which characterizes them,
a similarity of trachyte occurring only alternately. Colima
and Popocatepetl consist of oligoclase with augite, and conse-
quently have the trachyte of Chirnborazo or Teneriife;
Toluca and Orizaba consist of oligoclase with hornblende,
and consequently have the rock of ^gina and Kozelnik.
The recently formed volcano of Jorullo, which is scarcely
more than a large eruptive hill, consists almost alone of
scoriaceous lavas, resembling basalt and pitchstone, and
seems more like the trachte of Toluca than that of Colima.

4G8 COSMOS.

In these considerations on the individual diversity of tho
mineralogical constitution of neighbouring volcanoes, we find
a condemnation of the mischievous attempt to introduce a
name for a species of trachyte, derived from a mountain-
chain, chiefly volcanic, of more than 7200 geographical miles
in length. The name of Jura limestone, which I was the
first to introduce,8^ is unobjectionable, because it is taken
from a simple unmixed rock ; from a chain of mountains
whose antiquity is characterised by its containing organic
remains. It would in like manner be unobjectionable to
designate trachyte-formations after particular mountains, —
to make use of the expression Teneriffe-trachyte or Etna-
trachyte for decided oligoclase or labradorite formations.
So long as there was an inclination among geologists to find
albite everywhere among the veiy different kinds of felspar
which are peculiar to the chain of the Andes, every rock in
which albite was supposed to exist was called andesite. I
first meet with the name of this mineral, with the distinct
definition that "andesite is composed of a preponderating
quantity of albite and a small quantity of hornblende," in
the important treatise written in the beginning of the year
1835 by my friend Leopold von Buch on "Craters of upheaval
and volcanoes"** This tendency to find albite every where

84 In the course of a geological tour which I made, in 1795, through
the south of France, western Switzerland, and the north of Italy, I had
satisfied myself that the Jura limestone, which Werner reckoned among
his Muschel-kalk, constituted a peculiar formation. In my treatise
on subterranean gases, published by my brother, Wilhelm von Hum-
boldt, in 1799, during my residence in South America, this formation,
which I provisionally designated as Jura limestone, was for the first
time mentioned (s. 39). This account of the new formation was imme-
diately transferred to the Oberbergrath Karsteu's miueralogical table?,
at that time so generally read (1800, p. 64, and preface, p. vii), I named
none of the petrifactions which characterise the Jura formation, and in
relation to which Leopold von Buch has acquired so much credit
(1839) ; I erred likewise in the age ascribed by me to the Jura forma-
tion, supposing it to be older than muschel-kalk, on account of its
propinquity to the Alps, which were considered older than Zechstein.
In the earliest tables of Bucklancl, on the Superposition of strata in the
British Islands, the Jura limestone of Humboldt is reckoned as belong-
ing to the upper oolite. Compare my Essai Geogn. sur le Gisement des
Roches, 1823, p. 281.

85 The name of Andesite first occurrs in print in Leopold von Buch's
treatise, read on the 26th March, 1835, at the Berlin Academy. That

TRUE VOLCAN03S. 469

lasted for five or six years, until renewed investigations of a

great geologist limits the appellation of trachyte to those cases in which
glassy felspar is contained, and thus speaks in the above treatise,
which was not printed till 1836 (Poggend. Annal., Bd. xxxvii, s.
188 — 190): — "The discoveries of Gustav Rose, relating to felspar,
have shed a new light on volcanoes and geology in general, and the
minerals of volcanoes have in consequence presented a new and totally
unexpected aspect. After many careful investigations in the neigh-
bourhood of Catanea and at Etna, Elie de Beaumont and I have con-
vinced ourselves that felspar is not to be met with on Etna, and
consequently there is no trachyte either. All the lava-streams, as well
as all the strata in the interior of the mountain, consist of a mixture of
augite and labradorite. Another important difference in the minerals
of volcanoes is manifested when albite takes the place of felspar, in
which case a new mineral is formed, which can no longer be denomi-
nated trachyte. According to G. Rose's (present) investigations, it may
be considered tolerably certain that not one of the almost innumer-
able volcanoes of the Andes consists of trachyte, but that they all
contain albite in their constituent mass. This conjecture seems a very
bold one, but it loses that appearance when we consider that we have
become acquainted, through Huinboldt's journeys alone, with one-half
of these volcanoes and their products in both hemispheres. Through
Meyen we are acquainted with these albitiferous minerals in Bolivia
and the northern part of Chili; through Poppig, as far as the southern-
most limit of the same country ; through Erman, in the volcanoes of
Kamtschatka. Their presence being so widely diffused and so distinctly
marked, seems sufficiently to justify the name of andesite, under which
this mineral, composed of a preponderance of albite and a small quan-
tity of hornblende, has already been sometimes noticed." Almost at
the same time that this appeared, Leopold von Buch enters more into
the detail of the subject in the addenda with which, in 1836, he so
greatly enriched the French edition of his work on the Canary Islands.
The volcanoes Pichincha, Cotopaxi, Tungurahua, and Chimborazo, are
all said to consist of andesite, while the Mexican volcanoes were called
genuine (sanidiniferous) trachytes (Description physique des lies Canaries,
1836, pp. 486, 487, 490, and 515). This lithological classification of the
volcanoes of the Andes and those of Mexico shows that, in a scientific
point of view, such a similarity of mineralogical constitution and the
possibility of a general denomination derived from a large extent of
country, cannot be thought of. A year later, when Leopold von Buch
first made mention, in Poggendorjfs Annalen, of the name of Andesite,
which has been the occasion of so much confusion, I committed the
mistake myself of making use of it on two occasions; — once, in 1836,
in the account of my attempt to ascend Chimborazo, in Schumacher's
Jakrbuch, 1837, s. 204, 205 (reprinted in my Kleinere Schriften,
Bd. i, s. 160, 161), and again, in 1837, in the treatise on the high-
land of Quito (in Poggend. Ann., Bd. xl, s. 165). "Recent times have
taught us," I observed, already strongly opposing my friend's conjecture
as to the similar constitution of all the Andes-volcanoes, " that the

4:70 COSMOS.

more profound and less prejudiced character led to the recog-

diffevenfc zones do not always present the same (mineralogical) composi-
tion, or the same component parts. Sometimes we find trachytes,
properly so called, characterised by the glassy felspar, as at the Peak
of Tenerifie and in the Siebengebirge near Bonn, where a little albite ia
associated with the felspar, — felspathic trachytes, which, as active
volcanoes, exhibit abundance of obsidian and pumice ; sometimes
melaphyre, and doleritic mixtures of labradorite and augite, more
nearly resembling the basalt formation, as at Etna, Stromboli, and
Chimborazo ; sometimes albite with hornblende prevails, as iu the
lately so-called andesites of Chili and the splendid columns, described
as dioritic-porphyry, at Pisoje near Popayan, at the foot of the volcano
of Purace", or in the Mexican volcano of Jorullo ; finally, they s-re some-
times leucite-ophyrs, a mixture of leucite and augite, as in the Somma,
the ancient wall of the crater of elevation of Vesuvius." By an acci-
dental misinterpretation of this passage, which shows many traces of
the then imperfect state of geological knowledge (felspar being still
ascribed to the Peak of Teneriffe instead of oligoclase, labradorite to
Chimborazo, and albite to the volcano of Toluca), that talented investi-
gator Abich, who is both a chemist and a geologist, has erroneously
attributed to myself the invention of the term andesite as applied to a
trachj'tic, widely-dispersed rock, rich in albite (Pogysnd. Ann.,
Bd. ii, 1840, s. 523), and has given the name of andesine to a new
species of felspar, first analysed by him, but still somewhat enigmati-
cal in its nature, "with reference to the mineral (from Marmato, uear
Popayan) in which it was first observed." The andesine (pseudo-albite
in andesite) is supposed to occupy a middle position between labradorite
and oligoclase ; at the temperature of 55°.7 its specific gravity is 2.733',
while that of the andesite in which the andesine occurred is 3.593.
Gustav Rose doubts, as did subsequently Charles Deville (Etudes de
Lithoiogie, p. 30), the individuality of andesine, as it rests only on a
single analysis of Abich, and because the analysis of the felspathic
ingredient in the beautiful dioritic-porphyry of Pisoje near Popayan,
brought by me from South America, which was performed by Francis
(Poggend., Bd. lii, 1841, s. 472) in the laboratory of Heinrich Rose,
while it certainly shows a great resemblance to the andesine of Mar-
mato, as analysed by Abich, is, notwithstanding, of a different com-
position. Still more uncertain is the andesine in the syenite of
the Vosges (from the Ballon de Servance, and Coravillers, which Delesse
has analysed). Compare G. Rose, in the already often-cited Zeitschrift
cler Deutscken geologischen Gesdlschaft, Bd. i, for the year 1849, s. 369.
It is not unimportant to remark here that the name andesine, intro-
duced by Abich as that of a simple mineral, appears for the first time
in his valuable treatise entitled, Beitrag zur Eenntniss des Feldspaths
(in Poggend. Ann., Bd. 1, s. 125, 341, Bd. li, s. 519), in the year
1840, which is at least five years after the adoption of the name ande-
site, instead of being prior to the designation of the mineral from which
it is taken, as has been sometimes erroneously supposed. In the forma-
tions of Chili which Darwin BO frequently calls andesitic granite

TRUE VOLCANOES. 47 1

aition of the trachytic albites as oligoclase.83 Gustav Host.
has come to the general conclusion that it is very doubtful
whether albite occurs at all among the minerals as a real and
essential element of commixture ; consequently, according to
the old conception of andesite, this mineral would actually
be wanting in the chain of the Andes.

The mineralogical condition of the trachytes is imperfectly
recognised if the porphyritically enclosed crystals cannot be
separately examined and measured, in which case, the in-
vestigator must have recourse to the numerical proportions
of the earths, alkalies and metallic oxides, which the result
of the analysis furnishes, as well as to the specific gravity of

and andesitic porphry rich in albite (Geological Observations on South
America, 1846, p. 174), oligoclase may also very likely be obtained.
Gustav Rose, whose treatise on the nomenclature of the minerals allied
to greenstone and greenstone-porphyry (in Poggendorff's Ann., Bel.
xxxiv, s. 1 — 30) appeared in the same year, 1835, in which Leopold von
Buch employed the name of andesite, has not, either in the treatise just
mentioned, or in any later work, made use of this term, the true defini-
tion of which is, not albite with hornblende, but in the Cordilleras of
South America, oligoclase with augae. The now obsolete account of
the designation of andesite, of Avhich I have perhaps treated too cir-
cumstantially, helps to show, like many other examples in the history
of the development of our physical knowledge, that erroneous or
insufficiently grounded conjectures (as, for instance, the tendency to
enumerate varieties as species) frequently turn out advantageous to
science, by inducing more exact observations.

86 So early as 1840, Abich described oligoclase-trachyte from the
summit-rock of the Kasbegk and a part of the Ararat (Ueber die Natur
und die Zusammensetzung der Vulkan-B'ddungen, s. 46), and even in
1835, Gustav Hose had the foresight to say that though "he had not
hitherto in his definitions taken notice of oligoclase and pericline, yet
that they probably also occur as ingredients of admixture." The belief
formerly so generally entertained that a decided preponderance of
augite or of hornblende might be taken to denote a distinct species of
the felspar family, such as glassy orthoclase (sanidine), labradorite or
oligoclase, appears to be very much ?haken by a comparison of the
trachytes of the Chimborazo and Toluca rocks, belonging to the fourth
and third division. In the basalt-formatiou, hornblende and a«gite
often occur in equal abundance, which is by no means the case in the
trachytes; but I have met with augite crystals, quite isolated, in
Toluca rock, and a few hornblende crystals in portions of the Chim-
borazo, Pichincha, Purace, and Teneriffe rocks. Olivines, which are so
very rarely absent in the basalts, are as great a rarity in trachytes as
they are in phonolites ; yet we sometimes find, in certain lava-streams,
olivines formed in great abundance by the side of augites. Mica is on the

472 COSMOS.

the seemingly amorphous mass to be analysed. The result
is obtained in a more convincing and more certain manner
if the principal mass, as well as the chief elements of the
mixture, can be singly investigated both mineralogically and
chemically. This is the case with the trachytes of the Peak
of Teneriffe and those of Etna. The supposition that the
principal mass consists of the same small, inseparable, com-
ponent parts which we recognise in the large crystals appears
to be by no means well grounded, for, as we have already
noticed, as shown in Charles Deville's work, the apparently
amorphous principal mass generally furnishes more silicic
acid than would be expected from the nature of the felspar
and the other visible commixed elements. Among the
leucite-ophyrs, as Gustav Rose observes, a striking contrast is
exhibited, even in the specific difference of the prevailing
alkalies (of the potash containing interspersed leucites) and
the almost exclusively natroniferous principal mass.87

But along with these associations of augite with oligoclaee,
augite with labradorite, and hornblende with oligoclase, which
are referred to in our classification of the trachytes, and which
especially characterise them, there exist likewise in each vol-

whole very unusual in basalt, and yet some of the basaltic summits of
the Bohemian central mountains, first described by Reuss, Freieslebeu,
and myself, contain plenty of it. The unusual isolation of certain
mineral bodies, and the causes of their legitimate specific association,
probably depend on many still undiscovered causes of pressure, tempe-
rature, fluidity, and rapidity in cooling. The specific differences of the
.association are, however, of great importance, both in the mixed rocks
and in the masses of mineral veins ; and in geological descriptions, noted
down in the open air, in sight of the object described, the observer
should be careful not to make any mistake as to what may be a prevail-
ing, or at least a rarely absent member of the association, and what
may be sparingly or only accidentally combined. The diversity which
prevails in the elements of a mixture, — for instance, in the trachytes, —
is repeated, as I have already noticed, in the rocks themselves. In both
continents there exist large tracts of country in which trachyte forma-
tions and basalt formations as it were repel each other, as basalts and
phonolites; and there are other countries in which trachytes and
basalts alternate with each other in tolerably close proximity (see
Gustav Jenzsch, MonograpJiie der bohmischen Pkonolithe, 1856, s.
1—7).

s" See Bischof, Chemische und pkysikalische Geologic, Bd. ii,
185], & 2288, 2297; Roth, Monographic des Vesuvs. 1857, s,
805.

TRUE VOLCANOES. 473

cano other easily recognisable, unessential elements of com-
mixture, whose presence in large quantities or total absence
in different volcanoes, often situated very near to each other,
is very striking. Their occurrence, either in frequent abun-
dance, or else at long and separate intervals, depends probably
in one and the same natural laboratory on various conditions
of the depth from which the matter originally came, the tem-
perature, the pressure, the fluidity, or the quicker or slower
process of cooling. The fact of the specific occurrence or the
absence of certain ingredients is opposed to certain theories,
such as the derivation of pumice from glassy felspar or
from obsidian. These views, which have not been altogether
lately adopted, but originated as early as the end of the 1 8th
century from a comparison of the trachytes of Hungary and
of Teiieriffe, engaged my attention for several years in Mexico
and the Cordilleras, as my journals will testify. From the
great advancement which lithology has undeniably made in
modern times, the more imperfect definitions of the mineral
species, made by me during my journey have, through Gustav
Hose's careful mineralogical elaboration of my collections,
been improved and accurately certified.

MICA.

Black or dark-green magnesian mica is very abundant in
the trachytes of the Cotopaxi, at an elevation of 14,470 feet
between Suniguaicu and Quelendafia, as also in the subter-
ranean pumice-beds of Guapu]o and Zumbalica at the foot
of Cotopaxi,88 but 16 miles distant from the same. The
trachytes of the volcano of Toluca are likewise rich in mag-
nesian mica, which is wanting in the Chimborazo.89 In the
Continent of Europe micas have shown themselves in abun-
d ;nce : at Vesuvius (for example in the eruptions of 1821 —
1823, according to Monticelli and Covelli) ; in the Eifel in
the old volcanic Bombs of the Lacher Lake ;*° in the basalt

88 Cosmos, see above, p. 343.

89 It is almost superfluous to mention that the term wanting signifies
only that, in the investigation of a not inconsiderable portion of vol-
canoes of large extent, a particular sort of mineral has hitherto been
vainly sought for. I wish to distinguish between what is wanting (not
being found), being of very rare admixture, and what, though more
abundant, is still not normally characteristic.

90 Carl vou Oeynhausen, Erkl der yeogn. Karte des Lacher Sees. 1847,
B.3S.

474 COSMOS.

of the Meronitz, of the marly Kausawer Mountain and espe«
cially of the Camay er summit91 of the central Bohemian
chain j more rarely in the phonolite,93 as well as in the dole-
rite of the Kaiserstuhl near Freiburg. It is remarkable
that in the trachytes and lavas of both continents not only
no white (chiefly bi-axal) potash-mica is observable, but
that it is entirely dark-coloured (chiefly uni-axal) magnesian-
mica, and that this exceptional occurrence of the magnesia-
mica is extended to many other rocks of eruption and plu-
tonic rocks, such as basalt, phonolite, syenite, syenitic-
slate, and even granitite, while the granite proper contains
at one and the same time, white alkaline-mica and black or
brown magnesia-mica.93

GLASSY FELSPAR.

This kind of felspar, which plays so important a part
in the action of European volcanoes ; in the trachytes of
the first and second division (for example, on Ischia, in the
Phlegrsean Fields, or the Siebengebirge near Bonn), is proba-
bly entirely wanting in the New Continent, in the trachytes
of active volcanoes. This circumstance is the more striking
as sanidine (glassy felspar) belongs essentially to the argen-
tiferous, non-quartzose Mexican porphyries of Moran, Pa-
chuca, Villalpando and Acaquisotla, the first of which are
connected with the obsidians of Jacal. 94

91 See the Berymannisches Journal, von Kohler und Hofmann, 5ter
Jahrgang, Bd. i, 1792, s. 244, 251, 265. Basalt rich in mica, as on
the Gamayer summit in the Bohemian centre mountains, is a rarity. I
visited this part of the Bohemian central range in the summer of 1792,
in company with Carl Freiesleben, afterwards my companion in my
Swiss tour, who has exercised so great an influence over rny geological
and mining education. Bischof doubts all production of mica by the
igneous method, and considers it a metamorphic product by the moist
method. See his Lehrbuch der ckem. und physikal. Geologic, Bd. ii,
s. 1426, 1439.

92 Jenzsch, JBeitraye zurKenntn/ss der Pkonolithe, in der Zeitschrift der
Dcutschen Geoloyischen Gesellsckaft, Bd. viii, 1856, s. 36.

93 Gustav Rose, Ueber die zur Granitgruppe yehoriyen Gzbirysarten,
ibi'.l,, Bd. i, 1849, s. 359.

!4 The porphyries of Moran, Real del Monte and Regla (the latter
celebrated for the rich silver mines of the Veta Biscayna, and
the vicinity of the obsidians and pearlstones of the Cerro del Jacal
and the Messerberg, Cerro de las Navajas), like almost all the metal-
liferous porphyries of America, are quite destitute of quartz (ou
and other analogous phenomena in Hungary, see Humboldt,

TBUE VOLCANOES. 475

HOR^BLEN'DE AND AUGITE.

In this account of the characteristics of six different divi-
sions of the trachytes, it has been already observed how the
same minerals which occur as essential elements of commix-
ture (for example, hornblende in the third division, or tha
Toluca rock), appear in other divisions in a separate or spo-
radic condition (as in the fourth and fifth divisions, in the
rock of Pichincha and of Etna). I have found hornblende,,

(jeognostique sur le Gisement des Roches, pp. 179 — 188 and
190 — 193). The porphyries of Acaquisotla, however, on the road
from Acapulco to Chilpanzingo, as well as those of Villalpando to
the North of Guauaxuato, which are penetrated by auriferous veins,
along with the sauidine contain also grains of brownish quartz. — »
The small inclosures of grains of obsidian and glassy felspar being
on the whole rare in the volcanic rocks at the Cerro de las Navajas,
arid in the Valie de Santiago, so rich in basalt and pearl -stone,
which is traversed in going from Valladolid to the volcano of Jorullo,
I was the more astonished at finding at Capula and Pazcuaro, and
especially near Yurisapundaro, all the ant-hills filled with beautifully
shining grains of obsidian and sanidine. This was in the month of
September, 1803 (Nivellement barometr. p. 327, No. 366, and Essai
geoynost. sur le Gisement des Roches, p. 356). I was amazed that Such
small insects should be able to drag the minerals to such a distance.
It has given me great pleasure to find that an active investigator, M.
Jules Marcou, has observed something exactly similar. " There exists,"
he says, " on the high plateaux of the Rocky Mountains, and particu-
larly in the neighbourhood of Fort Defiance (to the west of Mount
Taylor), a species of ant which, instead of using fragments of wood
and vegetable remains for the purpose of building its dwelling, employs
only small stones of the size of a grain of maize. Its instinct leads it
to select the most brilliant fragments of stones, and thus the ant-hill
is frequently filled with magnificent transparent garnets and very pure
grains of quartz." (Jules Marcou, Resume explicatif d'une Carte geogn.
des Etats-unis, 1855, p. 3.)

Glassy felspar is very rare in the present lavas of Vesuvius, but
this is uot the case in the old lavas, for instance in those of the eruption
of 1631, where it occurs along with crystals of leucite. Sanidine is
also found in abundance in the Arso lava-stream, from Cremate towards
Ischia, of the year 1301, without any leucite ; but this must not be con-
founded with the older stream, described by Strabo, near Montag*
none and Rotaro (Cosmos, see above, pp. 265, 427). Glassy fel-
spar is not only rare in the trachytes of Cotopaxi and other vol-
canoes of the Cordilleras generally, but is equally so in the subterranean
pumice-quarries at the foot of the Cotopaxi. What was formerly de-
scribed aa sanidine are crystals of oligoclaae.

476 COSMOS.

though not in large quantities, in the trachytes of the vol-
canoes of Cotopaxi, Rucu-Pichincha, Tungurahua and Anti-
sana, along with augite and oligoclase, but scarcely ever along
with these two minerals on the slope of the Chimborazo up
to a height of more than 19,000 feet. Among the many speci-
mens which I brought from Chimborazo, hornblende is recog-
nized only in two, and even then in small quantity. In the
eruptions of Vesuvius in the years 1822 and 1850, augite
and crystals of hornblende (these nearly 9 Parisian lines in
length) were contemporaneously formed by exhalations of
vapours on fissures.95 The hornblende of Etna, as Sar borius von
Waltershausen observes, belongs especially to the older lavas.
That remarkable mineral, so widely diffused in Western A sia
and at several points of Europe, which Gustav Rose has de-
nominated Uralite, being allied in structure and crystalline
form to hornblende and augite,96 I here once more gladly
point attention to the first occurrence of uralite crystals in
the New Continent ; — they were recognised by Rose in a
piece of trachyte which I abstracted from the slope of the
Tungurahua, 3200 feet below the summit.

LEUCITE.

Leucites, which in Europe belong exclusively to Vesuvius,
the Rocca Monfina, the Albanian Mountains near Rome, the
Kaiserstuhl in the Breisgau, and the Eifel (in the western
environs of the Lachar Lake in blocks, and not in the con-
tiguous rock, as in the Burgberge near Rieden), have never
yet been found in volcanic rocks of the New Continent, or
the Asiatic portion of the old. Leopold von Buch discovered
them round an augite-crystal as early as the year 1798, and
described in an admirable treatise their frequent forma-
tion.97 The augite-crystal round which, according to this
great geologist, the leucite is formed, is seldom wanting, but
appears to me to be sometimes replaced by a small grain or
morsel of trachyte. The unequal degrees of fusibility, be-
tween the grain of trachyte and the surrounding mass of

95 Roth, Monographic des Vesuvs. s. 267, 382.

96 See above, note 82 ; Rose, Reise nach dein Ural., Bd. ii, s. 369 ;
Bischof, Ckem. und PhysiTc. Geologic, Bd. ii, s. 528—571.

'# Gilbert's Annalen der PhysiTc., Bd. vi, 1800, B. 53;— Bischof;
Geologic, Bd. ii, s. 2265—2303.

TRUE VOLCANOES. 477

leucite raise some chemical difficulties to the explanation of
the mode in which the integumental covering is formed.
Leucites, partly detached, ace ording to Scacchi, and partly-
mixed with lava, were extremely abundant in the recent
eruptions of Vesuvius in 1822, 1828, 1832, 1845 and 1847.

OLIVINE.

Olivine being very abundant in the old lavas of Vesuvius98
(especially in the leucite-ophyrs of the Sornma) in the Arso of
Ischia, in the eruption of 1301, mixed with glassy felspar,
brown mica, green augite and magnetic iron, in the volcanoes
of the Eifel which emit lava-streams (for example, in the
Mosenberge westward of Manderscheid),99 and in the south-
eastern portion of TenerifTe in the lava-eruption of Guimar
in the year 1704, I have also searched for it very diligently,
but in vain, in the trachytes of the volcanoes of Mexico,
New Granada and Quito. Our Berlin collections contain
sixty-eight specimens of trachyte of the four volcanoes, Tun-
gurahua, Antisana, Chimborazo and Pichincha alone, 48 of

)s The recent lavas of Vesuvius contain neither olivine, nor glassy
felspar ; Roth. Mon, des Vesuvs. s. 139. According to Leopold von
Buch, the lava-stream of the Peak of Teneriffe of 1704, described by
Viera and Glas, is the only one which contains olivine (Descr. des lies
Canaries, p. 207). The supposition that the eruption of 1704 was the
first which had taken place since the conquest of the Canary Islands
at the end of the loth Century, has been shown by me in another
place (Examen Critique de I'Histoire de la Geoymphie, t.iii, pp. 143 — 146)
to be erroneous. Columbus saw the eruption of fire on Teneriffe, at
the time of his first voyage of discovery, on the nights from the 21st to
the 25th August, when he went in search of Dona Beatriz de Bobadilla,
on the Gran Canaria. It is thus noticed in the Admiral's journal,
under the Rubric of " Jueves, 9 de Agosto," which contains notices up
to the 2d September, — " Vieron salir gran fuego de la Sierra de la
Isla de Tenerife, que es muy alta en gran in an era," — " they saw a great
deal of fire rising with a grand appearance out of the mountain of the
Island of Teneritfe, which is very high ;" Navarrete, Col. de los Viayes
de los Espanoles, t. i, p. 5. The lady above named must not be
confounded with Dona Beatriz Henriquez of Cordova, — the mother of
his illegitimate son, the learned Don Fernando Colon, the historian of
his father, — whose pregnancy in the year 1488 so materially contributed
to detain Columbits in Spain, and to lead to the discovery of the New
World being made on account of Castille and Leon, and not for Portu-
gal, France, or England (see my Examen Critique, t. iii, pp. 350
and 367).

99 Cosmos, see above, p. 232.

478 COSMOS.

which were contributed by me and 20 by Boussingault.10*
In the basalt formations of the jN"ew World, olivine along
with augite is as abundant as in Europe ; but the black, ba-
saltic trachyte of Yana Urcu, near Calpi at the foot of the
Chimborazo,1 as well as those enigmatical trachytes called la
reventazon del volcan de Anzango,2 contain no olivine. It was
only in the great, brown-black lava-stream, with a crisp,
scoriaceous surface raised like a cauliflower, whose track
we followed in order to reach the crater of the volcano of
Jorullo, that we met with small grains of olivine imbedded.3
The prevailing scarcity of olivine in the modern lavas and
the greater part of the trachytes seems less striking when we
recollect that, essential as olivine appears to be for basalt in
general, yet (according to Krug von Nidda and Sartor ius
von Waltershausen) in Iceland and in the German Rhone
Mountains the basalt destitute of olivine is not distinguish-
able from that which abounds in it. The former it has been
the custom from the earliest times to call trap and waclce, the
latter we have in modern times denominated Anemasitc^
Olivines, which sometimes occur as large as a man's head in
the basalts of Rentieres in the Auvergne, attain also in the
Tinkler quarries, which were the object of my first youthful
researches to the size of 6 inches in diameter. The beautiful
Jrypersthene rock of Elfdalen in Sweden, much employed

100 A considerable portion of the minerals collected during my Ame-
rican Expedition, has been sent to the Spanish Mineral Cabinet, to the
King of Etruria, to England and to France. I do not refer to the geologi-
cal and botanical collections which my worthy friend and fellow-labourer
Bonpland possesses, with the twofold right of self-collection and self-
discovery. This extensive dispersion of the materials, (which, from the
very exact account given of the places in which they originated, does
not prevent the maintenance of the groups in their geographical rela-
tions,) has this advantage that it facilitates the most comprehensive and
exact definition of those minerals whose substantial and habitual asso-
ciation characterises the different kinds of rocks.

1 Humboldt, Kldnere Schriften, Bd. i, s. 139.

2 Ibid, s. 202, and Cosmos, see ab^ve, p. 232.

3 Humboldt, Kl. Schr. vol. i, p. 344. I have also found a great deal
of olivine in the Tezontle (cellular lava, or basaltic amygdaloid ? — in
Mexican, tetzontli, i.e., stone-hair, from tetl, stone, and tzontli, hair)
belonging to the Cerro de Axusco in Mexico.

4 Sartorius von Waltershausen, Physisch-ycographische £kizze von
Island, s. 64.

TRUE VOLCANOES. 479

for ornamental purposes,* a granulated mixture of hyper-
sthene arid labradorite, which Berzelius has described as sye-
nite, likewise contains olivine,6 as does also (though more
rarely) the phonolite of the Pic de Griou, in the Cantal.6
While, according to Stromeyer, nickel is a very constant ac-
companiment of olivine, Kumler has on the other hand
discovered arsenic in it,7 a metal which has been found in the
most recent times widely diffused in so many mineral springs,
and even in sea-water. The occurrence of olivine in meteoric
stones8 and in artificial scoria^ as investigated by Sefstrom,"
I have already mentioned.

OBSIDIAN.

As early as in the spring and summer of 1799, while I was
preparing in Spain for my voyage to the Canary Isles, there
prevailed generally among the mineralogists in Madrid, —
Hergen, Don Jose Clavijo, and others, — the opinion that
pumice was entirely derived from obsidian. This opinion
had been founded on the study of some fine geological
collections from the Peak of Teneriffe, and a comparison of
them with the phenomena which Hungary furnishes, although
the latter were at that time explained chiefly in accordance
with the jSTeptunian views of the Freiberg school. Doubts
of the correctness of this theory of formation, awakened at an
early period in my mind by my observations in the Canary
Isles, the Cordilleras of Quito, and in the range of Mexican
volcanoes,10 impelled me to direct my most earnest attention

[* It is there cut into vases, sometimes of a considerable size, and
other ornamental objects. From the high polish it takes, and the
contrast of its colours, it is one of the most beautiful stones in
existence.— Tr.]

5 Berzeliufe, Sechster Jaltresbemcht, 1827, p. 392; Gustav Rose, in
Poggend. Ann. vol. xxxiv, 1835, p. 14 (Cosmos, vol. i, p. 464).

6 Jenzsch, Pkonolithe, 1856, p. 37, and Seuft, in his important work,
Classification der Felsarten, 1857, p. 187. According to Scacchi olivine
occurs also, along with mica and augite, in the lime-blocks of the
Somma. I call these remarkable masses erupted blocks, not lavas, for
the Somroa appears never to have ejected the latter.

' Poggend. Annul. Bd. xlix, 1840, s. 591, and Bd. Ixxxiv, s. 302;
Daubrde in the Annales des Mines, 4me Serie, t. xix, 1851, p. 669.

8 Cosmos, vol. i, p. 119, and vol. iv, p. 595.

9 Ibid. vol. i, p. 269, note*.

10 Humboldt, Personal Naraiive, vol. i, p. 113 (Bohn's Edition).

ISO COSMOS.

to two groups of facts ; — first, the different nature of the en-
closures of obsidians and pumice in general, and secondly,
the frequency of the association or entire separation of them
in well investigated, active volcanic structures. My journals
are filled with notices on this subject, and the specific defi-
nition of the imbedded minerals has been ascertained by the
most varied and most recent investigations of my ever ready
and obliging friend, Gustav Rose.

Both glassy felspar and oligoclase occur in obsidian as
well as in pumice, and frequently both of them together.
As examples may be cited, — the Mexican obsidians of the
Cerro de las Navajas on the eastern slope of the Jacal,
collected by me. — those of Chico, with many crystals of
mica, — those of Zimapan to the S. S. W. of the capital of
Mexico, mixed with small distinct crystals of quartz, and the
pumice of the Rio Mayo (on the mountain-road from Popayan
to Pasto) as well as those of the extinct volcano of Sorata,
near Popayan. The subterranean pumice quarries near
Liactagunga11 contain a large quantity of mica, oligoclase,
and (which is very rare in pumice and obsidian), hornblende
also ; the latter, however, is also found in the pumice of the
volcano of Arequipa. Common felspar (orthoclase) never
occurs in pumice along with saiiidine, nor is augite ever
present. The Somma, not the cone of Vesuvius itself, con-
tains pumice, enclosing earthy masses of carbonate of lirne.
It is by this remarkable variety of a calcareous pumice that
Pompeii was overwhelmed.1* Obsidians are rare in genuine
lava-like streams ; they belong almost solely to the Peak of
Teneriffe, Ltpari, and Volcano.

Passing now to the association of obsidian and pumice in
one and the same volcano, the following facts appear.
Pichincha possesses large pumice-fields and no obsidian.
Chimborazo, like Etna, whose trachytes, however, have a

11 See above, p. 342.

12 Scacchi, Oaservazioni criticJte sulla manicra come fu scpellito Tantica,
Pompei, 1843, p. 10, in opposition to the theory proposed by Carmine
Lippi, and afterwards shared by Tondi, Tenore, Pilla, and Dufrenoy,
that Pompeii and Herculaneum were not overwhelmed by rapilli
and ashes direct from the Somma, but that they were conveyed
there by water. Iloth, Monogr. cks Vesuvs. 1857, 5. 458, sea
above, p. 429.

TliUE VOLCANOES. 481

totally different composition (containing labraclorite instead
of oligoclase), shows neither obsidian nor pumice ; this same
deficiency I observed on my ascent of the Tungurahua. The
volcano Purace, near Popayan, has a great deal of obsidian
mixed in its trachytes, but has never yielded any pumice.
The immense plains out of which rise the Ilinissa, Carguai-
razo, and Altar are covered with pumice. The subterranean
pumice- quarries near Lactacunga, as well as those of
Huichapa south-east of Queretaro; and the accumulations
of pumice at the Rio Mayo,13 those near Tschegem in the
Caucasus,14 and near Tollo15 in Chili, at a distance from active
volcanic structures, appear to me to belong to the phenomena
of eruption from the numerous fissures in the level surface of
the earth. Another Chilian volcano, that of Antuco,16 (of
which Poppig has given a description as scientifically impor-
tant as it is agreeably written) produces, like Vesuvius,
ashes, triturated rapilli (sand), but gives out no pumice,
no vitrified or obsidian-like mineral. Without the presence
of either obsidian or glassy felspar, we sometimes meet with
pumice in trachytes of very dissimilar composition, although
in many cases it is not present. Pumice, as Charles Darwin
observes, is entirely wanting in those of the Archipelago of
the Galapagos. We have already remarked in another place
that cones of cinders are wanting in the mighty volcano of
Mauna Loa in the Sandwich Islands, as well as in the vol-
canoes of the Eifel " which once emitted lava-streams.
Though the island of Java contains a series of more than
forty volcanoes, of which as many as twenty-three are still
active, yet Junghuhn was only able to discover two points
in the volcano of Gunung Guntur, near Bandong and the
great Tengger Mountains,18 in which masses of obsidian have
been formed. These do not appear to have given occasion

13 Nivellement Barometrique, in Humboldt, Observat. Astron., vol. i,
p. 305, No. 149.

14 See above, p. 345.

15 For an account of the pumice-bill of Tollo, at a distance of two
days' journey from tbe active volcano of Maypu, which has itself never
ejected a fragment of such pumice, see Meyen, Reise urn die Erde,
Th. i, s. 338 und 358.

16 Poppig, Reise in Chile und Peru, Ed. i, s. 426.

17 See above, p. 392, and notes, pp. 320 — 3.

18 Franz Junghuhn, Java, Bd. ii, s. 388, 592.

VOL. V. 2 I

482 COSMOS.

to the formation of pumice. The sand-lakes of Dasar,
which lie about 6828 feet above the mean level of the sea,
are not covered with pumice, but with a layer of rapilli,
described as being obsidian-like, semi-vitrified fragments of
basalt. The cone of Vesuvius, which never emits pumice,
gave out from the 24th to the 28th October, 1822, a layer
18 inches thick of sand-like ashes, consisting of pulverised
trachytic-rapilli, which has never been mistaken for pumice.
The cavities and air-holes of obsidian in which crystals of
olivine, probably precipitated from vapours, have formed, as,
for example, in the Mexican Cerro del Jacal, are sometimes
ibund in both hemispheres to contain another kind of en-
closures, which seem to indicate the manner of their origin
and formation. In the wider portions of these long-extended,
and for the most part very regularly parallel cavities, frag-
ments of half-decomposed earthy trachyte are found embedded
Beyond these the cavity runs on in the form of a tail, as if a
gas-like elastic fluid had been developed by volcanic heat
in the still soft mass. This phenomenon particularly attrac-
ted the attention of Leopold von Buch when he visited the
Thomson collection of minerals at Naples in company with
Gay-Lussac and myself in the year 1805.19 The inflation of
obsidian by the operation of fire, which did not escape atten-
tion in the early period of Grecian antiquity,20 is certainly
caused by some such development of gas. According to
Abich, obsidians pass the more easily into cellular (not
parallel-porous) pumice, the poorer they are in silicic acid
and the richer they are in alkalies. It remains, however, very
uncertain, according to Rammelsberg's researches,21 whether
the tumefaction is to be ascribed to the volatilisation of
potash or hydrochloric acid. It is probable that similar
phenomena of inflation in trachytes rich in obsidian and
sanidine, in porous basalts and amygdaloids in pitch-stone,
tourmaline, and that dark-brown flint which loses its colour,
may have very different causes in the different materials

19 Leopold von Buch, in the Abkandl. der Akademie der Wiss. zu
Berlin, for the years 1812—1813 (Berlin, 1816), s. 128.

20 Theopkrastus de lapidibus, s. 14 and 15 (Opera ed. Schneider, t. i,
1818, p. 689, t. ii, p. 426, and t. iv, p. 551), says this of the "liparian
stone" (Ai7Ttt()aio£).

21 Rammelsberg, in Poggend. Annal., Bd. Ixxx, 1850, s. 464, and
fourth supplement to his Chemische Handworterbuch, s. 169; compare
also Bischof. GeoL, Bd. ii, s. 2224, 2232, 2280.

TRUE VOLCANOES. 483

themselves. An investigation which has now been long
looked for in vain, founded on accurate experiments, ex-
clasively directed to these escaping gaseous fluids, would
lead to an invaluable extension of our knowledge of the
geology of volcanoes, if at the same time attention were paid
to the operation of the sea- water in subterranean formations,
and to the great quantity of carburetted hydrogen belonging
to the commingled organic substances.

The facts which I have brought together at the end of this
section, the enumeration of those volcanoes which produce
pumice without obsidian, and those which yield a great deal
of obsidian and no pumice, — the remarkable, not constant,
but very diversified association of obsidian and pumice with
certain other minerals, early led me, during my residence in
the Cordilleras of Quito, to the conclusion that the formation
of pumice is the result of a chemical process, which may be
verified in trachytes of very heterogeneous composition,
without the necessity of a previous intervention of obsidian
(that is to say, without its pre-existence in large masses).
The conditions under which such a process is performed on a
large scale, are perhaps founded (I would here repeat) less on
the diversity of the material than on the gradation of heat,
the pressure determined by the depth, the fluidity, and the
length of time occupied in solidification. The striking, though
rare, phenomena presented by the isolation of immense sub-
terraneous pumice-quarries, far from any volcanic structures
(conical and bell-shaped mountains), lead me at the same time
to conjecture22 that a not inconsiderable — perhaps even, in
regard to volume, the greater, number of the volcanic rocks
have been erupted, not from upraised volcanic structures,
but from a net-work of fissures on the surface of the earth
frequently covering over in the form of strata a space of many
square miles. To these probably belong those masses of
trap of the lower Silurian formation of the south-west of
England, by the chronometric determination of which my
worthy friend, Sir Roderic Murchison, has so greatly in-
creased and heightened our acquaintance with the geological
construction of the globe.

22 See above, pp. 308, 330 332 — 336, 344 — 346, 354. For particulars
respecting the geographical distribution of pumice and obsidian in
the tropical zone of the New Continent, see Humboldt, Essai G&ognos-
tigue sur le gisement des Roches, <kc., 1823, pp. 340—342, and 344—347,

2 i 2

INDEX TO VOL. V.

ABTOH on volcanic phenomena in
Ghilan, 175; his views on the
Caucasian mountain system, 209,
360 ; analysis of the Chimborazo
rock, 462.

Aconcagua, volcano of, measure-
ment of, 288.

Acosta on the volcaucitos of Tur-
baco, 214.

Adanis, Mount, a volcano, 417.

JSnaria, the island of Apes, 265.

^Eolus, residence of, on Strongyle,
257.

Africa, determination of the mag-
netic equator in, by Sabine, 103 ;
its translation, 106 ; snowy
mountains in, 354; volcanoes
in, 354 ; their small number,
355.

African magnetic node, its varying
position, 103.

Agaschagokh, island of, 371.

Agreeable odour diffused from
certain volcanoes, 229.

Agua, Volcan de, described, 276.

Airy, density of the earth deter-
mined by, vii ; on terrestrial
magnetism, 79.

Alaid, great eruptions of the vol-
cano on the isle of, 372.

Albite, 469.

Aleutian islands, numerous volca-
noes in, 370.

Alps, temperature of springs in
the, 192.

America. See Central America,
Chili, Mexico, North-west Ame-
rica, Peru and Bolivia, Rocky
Mountains, South Sea.

Ampere on the cause of earth-
quakes, 168.

Ampolletas, 56.

Amsterdam, volcanic island of,
385.

Anahuac, series of volcanoes of,
280.

Anaxagoras, maxim of, verified, 7.

Andaman isles, volcanic pheno-
mena in the, 383.

Andes, large spaces in the chain
of, destitute of volcanoes, 282;
groups and distances, 283 ; spe-
cial direction of the three Cor-
dilleras, 292.

Andesite, 468, 471.

Andrea Bianco, his early charts,
exhibit the magnetic variation,
54.

Anemasite, 478.

Annular valleys, 231.

Ansango, lake of, 3.

Ansogorri, Father Joaquin, his de-
scription of the rise of the vol-
cano Jorullo, 310.

Ant-hills, in the Rocky Mountains,
their remarkable construction,
475.

Antilles, Little, volcanoes of the,
described, 421.

Antisana, the colossal mountain,
described, 331 , its dykes, 331 ;
lakes, 332.

Antuco, volcano of, 289.

Aphron, the northern pole of the
magnetic needle, 53.

Apparatus employed by Humboldt
for his 453 determinations of
height in the New World, 459.

Arabia, lava eniptions in, 357.

Arago on magnetic inclination,
107 ; his series of magnetic ob-
servations, vii.

Ararat, as a volcano, 361.

Arare, crater of, 393.

Arequipa, volcano of, 286.

Ai'gaeus, the volcano, 249.

Arimer, country of the, 266.

Aristotle on the fundamental

IXDEX.

485

principles of nature, 5 ; volcanic
phenomenon upon Hiera de-
scribed by, 229.

Arran, volcanic phenomena in,
350.

Artesian wells, Walferdin's obser-
vations on, 35.

Ascension, volcanic phenomena of
the island of, 352.

Asia, situation of the principal
volcanoes in, 297 ; volcanoes of
the western and central parts,
356 ; of Kamtschatka, 362 ; of
the islands of Eastern Asia, 367;
of the islands of Southern Asia,
377; of the Indian Ocean, 382.

Atlantic Ocean, volcanoes of the
islands of the, 351; presumed
submarine volcano, 353.

Atlantis of Solon, 179.

Atolls, or lagoon reefs, 388.

Attraction of the magnet known
to the Greeks and Romans, 50.

Augite, 475.

Aurora borealis, 152 ; observa-
tions of the black segment, 152;
colours observed in high lati-
tudes, 1 54 ; accompanying flee-
cy clouds, 155 ; influence on
terrestrial magnetism, 157; ob-
servations at Berlin and at Edin-
burgh, 158.

Auvergne, extinct volcanoes of,
238, 278.

Azores, craters of elevation in the,
227 ; the volcano Pico, 247.

Azufral de Quindiu, Humboldt's
visit to the, 221 ; change of tem-
perature observed by Boussin-
gault, 221.

Baily on the density of the earth,
31, 32.

Baker, Mount, a volcano, 418.

Banda, a volcanic island, 381.

Barba, the volcano, described,
273.

Barile, earthquake at, 173.

Barrancos on the slopes of vol-
canoes, 304.

Barren Island, one of the Anda-
mans, appearance of, as de-
scribed by Horsburgh, 383.

Basalt-like columns of Pisoje, 456.

Beaufort, Admiral, the Chimsera
described by, 257.

Beauvais, Vincent of, on the mag-
netic needle, 53.

Belcher, Sir E., magnetic observa-
tions by, 113.

Bell-shaped volcanic mountains,
228.

Berg, Albert, his description of
the burning spring, Chimsera,
257.

Berlin, aurora observed at, by
Humboldt, 158.

Bessel, determination of the size
and figure of the earth, 14, 27.

Biot, pendulum measurements by,
23.

Bolivia. See Peru.

Borda, his services in equipping
the expedition of La Perouse,
61.

Borneo, the Giava Maggiore of
Marco Polo, 379 ; doubtful
whether volcanoes exist there
379 ; great number of volcanoes
in its vicinity, 379.

Bo-shan, eruption of the volcano,
437.

Bouguer's experiments on the de-
viation of the plummet, 30 ; on
the pumice-quarries of Lactu-
cunga, 342.

Boxirbon, volcanoes of the isle of,
383.

Boussingault's method of deter-
mining the mean temperature,
40 ; on the cause of earthquakes,
170 ; on the matters ejected from
volcanoes, 335 ; on gases, 442.

Bove, Val del, on Etna, 225, 241.

Bramidos de Guanaxuato, 178.

Bravais on Artesian wells, 37; on
the black segment of the Au-
rora, 153.

Brisbane, Sir Thomas, his observa*
tory at Makerstoun, 123, 124.

486

INDEX.

British isles, volcanic phenomena

in the, 350, 483.
Bromo, a volcano in Java, its

crater lake, 302.
Brooke, Eajah, on the volcanic

appearances in Borneo, 380.
Brooks of cold water said to be

converted into thermal springs,

314.

Brown, Mount, a volcano, 418.
Buch, Leopold von, his work on

basaltic islands and craters of

elevation, 226 ; on the erupted

matters of Vesuvius, 235 ; on

the trachytes of Etna, 469.
Buddhist fancy as to the causa of

earthquakes, 177.
Bun'sen on fumaroles, 424.
Burkart, his visit to Jorullo, 318.

Calabria, earthquake in, in 1783,
172.

Calamatico, el, an ancient name for
the magnetic pole, 56.

Calbuco, Volcan de, 290.

California, list of the volcanoes of,
417.

Callaqui, volcano of, 290.

Canary Islands, eruptions in the,
477.

Capac-Urcu,an extinct volcano 282.

Cape of Good Hope, magnetic
observations at, 113.

Carbonic acid gas, considerations
on, 442.

Carbonic acid gas, jets of, 201.

Cascade Mountain range, in Cali -
fornia, 416.

Castillo, Fray Bias del, explores
the crater of Masaya, 260.

Catalans, advanced state of navi-
gation among the, 53, 54.

Caucasus, volcanic phenomena of
the, 208 ; a continuation of
the Thian-schan, 360; its ex-
tinct volcanoes, 360.

Cauldron-like depressions of volca-
noes, 231.

Cavanilles, his account of the
earthquake of Riobamba, 1 73.

Celebes, volcanoes of, 381.

Central America, linear volcanoes
of, 268, 272 ; number of volca-
noes in, 273; recommended for
further examination, 278.

Chacani or Charcani, volcano of,
286.

Chahorra, the crater of, on the
Peak of Teneriffe, 262.

Chatham Island, its position, 401 .

Chili, group of volcanoes in, 288 ;
their greatest elevation, where
attained, 296.

Chilian, Volcan de, 289.

Chiloe, submarine volcano near,
288.

Chimborazo, majestic dome, form
of, 2 ; ascent of, 464 ; conside-
rations on the height of the
mountain, 464.

Chimborazo rock, Rammelsberg's
analysis of, 461, Abich's, 462;
remarks on the differences be-
tween them, 463.

Chimsera, in Lycia, not a volcano,
but a perpetual burning spring,
212,257; analogous phenomenon
in the Kuen-lun, 438.

Chinal, volcano of, 290.

Chinese, early acquainted with
the polarity of the magnet, 50 f.
rope-boring, 219; early maps
of the, 434.

Chuapri, volcano of, 288.

Cinders, cones of, wanting in seve-
ral volcanoes which once emit-
ted lava-streams, 481; thickness
of the layers of, on Sangay, 265.

Circumvallations, volcanic, 230 ;
that of Oisans, in France, its
great extent, 231 ; of Mont
Blanc, 231.

Coal strata, 443.

Coan, the missionary, on the basin
of Kilauea, 393.

Coast Kange mountains, in Cali-
fornia, old volcanic rocks of the,
416.

Cofre de Perote, Humboldt'a
ascent of. 326.

INDEX.

487

Columbus determines astronomi-
cally a line of no variation, 54 ;
notice of an eruption on Tene-
riffe, by, 477.

Comangillas, Aguas de, a hot
spring, 197.

Commotion, waves of, in earth-
quakes, 171; theory of, 172;
attempt to explain the rotatory
shocks experienced in Calabria,
172.

Commotions of the earth in earth-
quakes often confined within
narrovr limits, 182.

Comoro islands, burning volcano
in the, 384.

Compass. See Mariner's Compass.

Compression, polar, 29.

Couchagua, a volcano, 275.

Conical volcanic mountains, 239.

Conseguira, eruption of, 274.

Copiapo, destruction of the town
of, 288.

Coquimbo, volcano of, 288.

Coral islands, number of, in the
Pacific, according to Dana, 390.

Corcovado, Volcan de, 290.

Cordilleras. See Andes.

Corea, volcanoes of, 376.

Cosima, small elevation of the
volcano of, 245.

Costa, Col. A., his experiments on
mean annual temperature, 41.

Cotopaxi, mineralogical composi-
tion of, 343.

Craters of elevation, 226 ; distin-

fuished from true volcanoes,
27. See also Volcanoes.
Crozet's group, traces of former

volcanic action in, 387.
Crust of the earth, considerations

on its varying thickness, 439.
Crystallized minerals of the Maars,

234 ; greater number found on

Vesuvius, 235.
Cueva de Autisana, 332.
Cyclades, volcanic phenomena in

the, 267.

Dana, James, his valuable re-

searches in the Pacific, 388 ;
his grouping of the basaltic and
coral islands, 390 ; on the vol-
canoes of the Sandwich Islands,
392.

Darwin, Charles, his enlarged
views on earthquakes and erup-
tions of volcanoes, 288 ; general
acknowledgment of obligations
of science to, 389.

Dasar, sand-lakes of, 482

Dechen, H. von, on volcanic phe-
nomena in the Eifel, 236

Declination. See Magnetism.

Degree, table of the increase in
length of the, from the equator
to the pole, 17.

Demavend, volcano of, 356, 357 ;
question of its altitude, 356.

Density of the earth, experiments
to determine, 30; Airy 's results,
vii.

Detritus dykes, 331.

Deville, on the structure and
colour of the mass in certain
volcanoes, 463.

Devonian slate, 231.

Diablo, Monte del, in California,
416.

Diamagnetism, its discovery by
Faraday, 49, 78.

Dio Cassius on the eruptions of
Vesuvius, 427.

Diodorus Siculus on the Phlegrsean
fields, 428.

Disturbances, magnetic, table of,
134.

Djebel el Tir, a volcano, 356.

Dome-shaped and bell-shaped
mountains peculiar aspect given
by, to the landscape, 229.

Domite, origin of the term, 450.

Dry fog of the summer of 1783,
421.

Duperrey, his observations on the
magnetic equatoi*, 104.

Earth, its size, configuration and
density, vii, 9 ; interior heat,
34, 246 ; magnetic activity, 49;

488

IND2X.

magnetic storms, 141 ; polar
light, 151 ; reaction of the
interior on the surface, 162
(see also Earthquakes, Volcanoes);
thickness of the crust of, pro-
bably very unequal, 169.

Earthquakes, variety of views as
to their cause, 167 ; the impulse,
167 ; translatory movements,
173; subterranean noises, 178;
velocity of propagation, 179 ;
distinguished, but improperly,
aa Plutonic and Volcanic, 180 ;
three groups of phenomena
which indicate the existence of
one general cause, 183 ; list of
memorable examples of these
phenomena, 183.

Earth-waves in volcanic phe-
nomena, 171.

Eastern Asia, volcanoes of the
islands of, 367.

Eclgecombe, Mount, a volcano,
269, 418; another in New
Zealand, 397.

Edinburgh, beautiful aurora ob-
served at, 158.

Edrisi on the land of Gog and
Magog, 359.

Eifel, extinct volcanoes of the,
231 ; two kinds of volcanic
activity distinguishable, 232 ;
Mitscherlich on the minerals,
235 ; Ehrenberg on the infusoria,
237.

Elburuz, as an extinct volcano, 362.

Elevation, question of the in-
fluence of, on magnetic dip and
intensity, 114 ; craters of, dis-
tinguished from true volcanoes,
227.

Elias, Mount, a volcano, 252, 419.

Elliot, Capt., on the magnetic
equator, 105.

Ellipticity of the earth, specula-
tions of the ancients on the, 26 ;
Bessel's determination, 27.

El Nuevo, a volcano, 274.

El Viejo, a volcano, measurements
of, 274.

El Volcancito, now a mountain of
ashes, 321.

Emanations from fumaroles, their
nature, 424.

Enceladus. See Typhon.

England, volcanic phenomena in,
350, 483.

Equator, magnetic. See Magnetic
equator.

Erebus, Mount, the volcano, 103,
249.

Ermau on the magnetic equator,
105 ; his researches on the vol-
canoes of Kamtschatka, 363.

Erupted blocks, 479.

Eruption, masses of, considera-
tions on, 225; craters of, 226.

Eruptions of volcanoes, considera-
tions on the general laws of,
255 ; varying heights to which
matters are cast, 264.

Etna, eruptions of, usually occur
within a space of six years, 255 ;
periods of its greatest activity,
257 ; height to which ejected
matters attain, 265 ; its tra-
chytes, 165.

Euboea, Strabo's description of an
earthquake in, 225.

Europe, active volcanoes of, 349 ;
extinct volcanoes and volcanic
phenomena, 231, 238, 350, 483.

Faraday's discovery of the para-
magnetic force of oxygen, 78 ;
important results expected from
it, 82, 99; on diamagnetism,
49, 78.

Fairweather, Mount, a volcano, 4 1 8.

Felspar, variety of minerals com-
prised under the denomination
of, 457, 474.

Ferdinandea, the volcanic island,
349.

Figure of the earth, attempts to
solve the problem, 13 ; deter-
minations of Bessel, 14 ; earlier
observations, 16.

Fissures caused by earthquakes,
173; volcanic, 226, 228; vol-

INDEX.

489

canoes upheaved on fissures,
265. See Volcanoes.

Fitzroy's magnetic observations,
71.

Floods in rivers, prognostication
of, 187.

Forbes, on the conductive power
of different rocks, 38.

Fogo, volcano of the Ilha do,
262.

Formosa, the turning-point of the
lines of volcanic elevation in
the islands of Eastern Asia, 369 ;
its volcanoes, 377.

Foucault's apparatus for demons-
trating the rotation of the
earth, 25.

France, extinct volcanoes of, 238,
278.

Franklin on frozen earth in the
north-west of America, 48 ; his
Arctic voyages, 65 ; search for
him, 65.

Franklin's Bay, volcano of,
more properly a salse, 419.

Fredonia, near Lake Erie, springs
of inflammable gas at, 213.

Fremont's hypsometrical investiga-
tions in North- West America,
410.

Fremont's Peak, 415.

French Alps, highest summit of
the, 230.

Frozen earth, its geographical ex-
tension, 46.

Fse-nan, a Chinese magnetic appa-
ratus, 50.

Fuego, Volcan de, described, 276.

Fumaroles, various classes of, 424;
Bunsen on their products, 424.

Fummarole of the Tuscan Ma-
remma, 211.

Fused interior of the earth, 246.

Galapagos, the, countless cones

and extinct craters, 400 ; pumice

not found there, 401.
Gal era Zamba, terrible eruptions

of flames and terrestrial changes

at, 218.

Gandavo, Fray Juan de, explores
the crater of Masaya, 260.

Gas, volcanic exhalations of, in-
quiry into, 441. See also
Springs.

Gauss, his theory of terrestrial
magnetism, 62.

Gay Lussaconthe chemical causes
of volcanic phenomena, 169 ;
on waves of commotion and
oscillation, 171.

Gemellaro, his estimate of the
height to which erupted bodies
ascend from Etna, 265.

Geographical distribution of vol-
canoes, 421 ; an abnormal phe-
nomenon in, noticed, 433.

Geological terms, origin of some,
450.

Geysirs, the, of Iceland described,
199.

Gilbert, William, lays down com-
prehensive views on the mag-
netic force of the earth, 57.

Glassy felspar. See Felspar.

Godivel, Lac de la, an extinct
volcano, 238.

Gog and Magog, oriental myth of,
359.

Gold, believed to be found in
volcanoes, 261 ; descent into
Masaya in search of it, 261.

Graham, his observation of the
hourly variations of the mag-
netic force, 60.

Graham Island, temporary for-
mation of, 349.

Grand Ocean, a term for the basin
of the South Sea, objected to,
404.

Granite,Mitscherlich's experiments
on the melting point of, 246.

Greece, has frequently suffered
from earthquakes, 177; great
number of thermal springs, 177.

Grenelle, the Artesian well of, 36.

Ground temperature, observations
on, 1 90. See also Frozen earth.

Guadeloupe, the Soufriere of, de-
scribed, 423.

490

INDEX.

Quagua-Pichincha, its meaning,

242.

Gualatieri, volcano of, 287.
Guanacaure, a volcano, 274.
Guanahuca (Guanegue?) volcano

of, 290.
Guettard's observations on extinct

volcanoes, 330.
Gunung, the Javanese term for

mountain, 299.
Gunung Tengger, a volcano in

Java, vast size of its crater, 301.
Guyot of Provins, his mention of

the magnetic needle, 53.

Hair-glass, a volcanic product,
392.

Hall, Capt. Basil, experiments to
determine the mean tempera-
ture of places within the tropics,
40; measurement of the vol-
canoes of Old Guatemala, 277 ;
his admirable description of
Sulphur Island, 377.

Halley's theory of four magnetic
poles, 58.

Hallmann, his classification of
springs, 205.

Hansteen on the magnetism of
the earth, 66.

Harton, pendulum experiments
at, relative to the density of the
earth, vii.

Hawaii, the volcanoes of, de-
scribed, 395.

Heat, distribution of, in the in-
terior of our globe, 34 ; hypo-
thesis of the depth of the fused
interior of the earth below the
present sea level, 246.

Hecla, the volcano, its aspect,
243 ; infrequency of its erup-
tions, 255 ; how classified by
Waltershausen, 351.

Helena, St., volcanic phenomena
of, 352.

Helen's, St., Mount, a vclcano,
417.

Hell, the cold, of the Buddhists
196.

Hephsestos, Volcano, the holy isle
of, 257.

Herefordshire, sedimentary rocks
of, 231.

Hesse, on the volcanoes of Central
America, 272.

Hiera, volcanic phenomena upon,
described by Aristotle, 229.

Himalayan chain, four highest
mountains of the, 287 ; known
to the Greeks as the elongated
Taurus, 434.

Hobarton, magnetic observations
at, 100.

Ho-cheu, a volcano, also called
Turfan, 356.

Hood, Mount, an extinct volcano,
417.

Hooker, Joseph, on the hot springs
of Momay, 197.

Hopkins on earthquakes, 168, 171,
174.

Horary variation of the declina-
tion not ascribable to the heat
of the sun, 82; maxima and
minima, at various magnetic
stations, 109.

Hornblende and augite, 475.

Hornos or Hornitos. See Hornitos.

Hornitos, low volcanic cones, 1 83 ;
further notices of them, 316,
322.

Horsburgh, description of Barren
Island by, 383.

Ho-schan and Ho-tsing, of Eastern
Asia, 219.

Humboldt, Alexander von, ob-
servations of temperature in
Mexico and Peru, 41 ; magnetic
observations by, 70, 96 ; his
determination of the magnetic
equator, 104 ; observations of
polar bands, 155 ; visit to the
scene of the earthquake of
Kiobamba, 1 73 ; observations of
the phenomena of an eruption
of Vesuvius, 181 ; barometrical
measurements of the same
mountain, 247 ; his definition
of the term "volcano," 287;

INDEX.

491

his visit to Joruilo, 313, 319;
the name Jura limestone intro-
duced by, 468 ; apparatus em-
ployed by, in the New World,
459 ; his mineralogical collec-
tions, 477 ; on the formation of
pumice, 483.

lumboldt, Alexander von, works
by, cited in the text or notes : —

Asie Centrale, 51, 101, 116,
148, 149, 176, 208, 210,
219, 220, 250, 295, 336,
356, 358, 360, 361, 372,
376, 438.

Atlas Geographique et Phy-
sique de la Nouvelle Es-
pagiie, 239, 247, 263, 309,
432.

Essai Geognostique sur le
Gisement des Roches, 221,
320, 444, 454, 468, 475, 483.

Essai sur la Geographic des
Plantes, 252, 458.

Essai Politique sur la Nou-
velle Espagne, 42, 197, 279,
280, 293, 310, 312, 326,
406, 418, 458.

Examen Critique de l?His-
toire de la Geographic, 51,
119, 126, 180, 244, 260.

Fragmens de Ge'ologie et de
Climatologie Asiatique,
372, 377.

Kleinere Schriften, 171, 214,
239, 291, 332, 336, 341,
451, 478.

Recueil d' Observation s As-
tronomiques, 41, 104, 143,
222, 251, 279, 315, 326,
444, 459, 464, 481.

Relation Historiquedu Voyage
aux Regions equinoxiales
(Personal Narrative, Bonn's
edit., 1852-3), 97, 112,115,
117, 173, 175, 187, 249,
250, 303, 422, 423, 479.

Views of Nature, 261, 365,
408, 427.

Vues des Cordilleres, 217,
239, 242, 247.

Hypersthene rock, its employment

for ornamental purposes, 478.
Hypsometry. of volcanoes, first

group, 246 ; second group, 247 ;

third group, 248 ; fourth group,

250 ; fifth group, 251.

Iceland, the Geysirs of, 198 ; mud
springs, 212 ; volcanoes, 351.

Ilha do Fogo, one of the Cape
Verd Islands, so called, 262.

Impulse in volcanic phenomena,
summary of views on, 167.

Inarima, 266.

Inclination, magnetic, 102 ; max-
ima and minima, 109 ; secular
variation, 111.

Indian Ocean, volcanoes of the,
382, 387.

Infusoria, universal diffusion of
the, 237.

Intensity of the magnetic ter-
restrial force, 57, 61, 87.

Interior of the earth, its reaction
•on the surface, 162. See also
Earthquakes, Volcanoes.

Invariable temperature, stratum
of, 39.

Ischia, 265.

Island of Desolation. See Ker-
guelen's Island.

Islands, temporary, enumerated,
349.

Islands and the shores of conti-
nents, great number of vol-
canoes found on, 431.

Islands of the Pacific, Dana's
classification of, 390.

Isluga, volcano of, 287.

Izalco, volcano of, described, 261 ;
its eruptions, 276,

Iztaccihuatl, a volcano, meaning
of the name, 239.

Jacob, valley of, on Ararat, 241.

Jakutsk, mean annual tempera-
ture of, 45: extreme variations.
45.

Jan Mayen, volcanoes of the island
of, 351.

402

INDEX.

Japan, notice of the volcanoes of,
communicated by Sielbold, 373.

Jaques de Vitry, his mention of
the magnetic needle, 53.

Java, large number of volcanoes
in, 297; their comparatively
low elevation, 299; direction of
the principal axis, 301 ; vast
craters of some, 301 ; ribbed
formation, 303 ; lava streams,
305 ; salses of, and mofette
grottoes, described by Jung-
huhn, 220 ; tertiary formations,
298.

Javanese names of mountains ex-
plained, 307.

Jefferson, Mount, 417.

Jesso, island of, 372 ; its nume-
rous volcanoes, 373.

Jorullo, rise of the volcano, 280,
309 ; description of, by eye-wit-
nesses, 310 ; visit of Humboldt
to, 313, 319; visit of Buckart,
and changes noticed by him,
318.

Juan Jayme, his scientific voyage,
55.

Julia the volcanic island, 349.

Julius, the proconsul, 196.

Jumnotri, hot well of, 198.

Junghuhn, his researches in Java,
220, 298.

Jura limestone, name introduced
by Humboldt, 468.

Kaimenes, upheaval of the three,
349.

Kamtschatka, the loftiest volcano
of Asia found in, 300; de-
scribed, 362.

Kerguelen's Island, extinct craters
of, 387.

Kilauea, the great crater of, not a
solfatara, 392.

Kina Bailu, a lofty mountain of
Borneo, 379.

Kirgish Steppe, former water-
courses of the, 437.

Kljutschewsk, the highest Asiatic
volcano, 300.

Korai. See Corea.

Kotzebue on the volcanic island
of Umnack, 230.

Krapf, discovery of a volcano in
Eastern Africa by, 354.

Krafto. See Saglialin.

Krasnajazarki, polar bands ob-
served by Humboldt at, 155.

Kreil on the magnetism of the
moon, 85.

Krusenstern on a presumed sub-
marine volcano, 353.

Kuen-lun, fire-springs of the,
438 ; the chain visited by the
brothers Schlagintweit, 438.

Kuopho on the magnetic needle,
51.

Kupffer on the frozen soil of
Northern Asia, 48.

Kurile isles, active volcanoes of
the, 372.

La Berarde, remarkable position
of the village of, 231.

Lactacunga, repeated destruction
of the town of, 342 ; subter-
ranean pumice quarries of, 342,
481.

Ladrone islands, volcanoes of, 395.

Lagoni of the Tuscan Maremma,
211.

Lamont deduces the law of the
period of alterations of decli-
nation, 84.

Lancerote, destruction of the
island of, 228.

Lava, recent, often perfectly simi-
lar to the oldest formations of
eruptive rock, 226; important
conclusion drawn therefrom,
226.

Lava fields, various names for, 324.

Lava streams rare in the volcanoes
of the Cordilleras of Quito, 277;
discovered in the eastern chain
of the Andes, 295 ; also in Java,
306; their essential character,
306 ; of Auverge, 330 ; of Etna,
465; of Hecla, 243; of Ter»
nate, 381.

INDEX.

493

Lazarus, St. Mount, volcano, 269.
Lelantus, in Euboea, eruption at,

225.
Lemnos, destruction of the moun

tain Mosychlos in, 349.
Letronne on earthquakes in Egypt?

177.

Leucite, 466, 476.
Limari, volcano of, 288.
Linschoten, notices the volcanoes

of Japan, 375.
Lipara, the volcano, question of

its identity, 256.
Lipari, the ancient Meligunis, 256;

lava stream found in, 341.
Llandeilo strata, volcanic frag-
ments found in the, 350.
Llanquihue, volcano of, 290.
Log, ship's, introduction of the,

an important era in navigation,

56.
Lombok, volcano on the isle of,

331.

Lucia, St., the volcano of, 422.
Lunar-diurnal magnetic variation,

viii.
Liitke, Admiral, on the volcanoes

of Kamtschatka, 363.
Luzon, active volcano in, 243.

Maars, in Germany, 231 , in Au-
vergne, 238.

Macas. See Sangay.

McLaughlin, Mount, its height,
417.

Madagascar, volcanic indications
in, 384.

Madeira, volcanic phenomena of,
352.

Magnet, attraction, but not pola-
rity of the, known to the Greeks
and Romans, 50; variations of
the, early known to the Chinese,
52 ; variation charts, 54 ; horary
periodical alterations, 60.

Magnetic disturbances, table of,
134.

Magnetic equator, its position and
change of form, 103 ; Hum-
boldt'a determinations, 1-J4 ;

Puperrey's observations, 104;
Elliot's, 105.

Magnetic intensity, 61 ; the know-
ledge of, due to Borda, 61 ; in-
clination chart, 61.

Magnetic needle, early known to
the Chinese, 50 ; its introduction
to Europe, 52 ; decimation, 54.

Magnetic observatories, 62.

Magnetic storms, 134.

Magnetic waggon, the, of the
Chinese, 51.

Magnetism, early researches in,
55, 57 ; increased activity of
observation in the 1 9th century,
62 ; table of magnetic investi-
gations, 63; influence of the
moon, viii.

Magnetism of mountain masses,
159.

Makerstoun, Sir Thomas Bris-
bane's observatory at, 123, 124.

Malpais, a term applied to lava
fields, 307.

Mandeira, the volcano, 273.

Mantschurei, extinct volcano in,
437.

Marco Polo, date of his travels, 53 ;
the mariner's compass known in
Europe before his time, 53.

Marcou, on the anthills in the
Eocky Mountains, 475.

Maribios, los, a line of six vol-
canoes, 274.

Mariner's compass known in Eu-
rope in the 12th century, 53;
English ships guided by it, in
1345, 56.

Marion's Island, traces of former
volcanic action on, 387.

Martinique, recent volcanic action
in the island of, 423.

Masaya, volcano of, described,
258 ; descent into the crater of,
260.

Mauna-Roa, a volcano of the Sand-
wich Islands, 250; its height
greatly exaggerated, 250; mean-
ing of the name, 245; described,
391; the largest volcano of tha

494

INDEX.

South Seas, 391; called also
Mouna Loa, 391; its lava-lake
of Kilauea, 393.

Maypu, volcano of, 289.

Medina, volcano of, 356.

Meligunis. See Lipari.

Methone, volcanic phenomena of
the peninsula of, 229.

Mexico, list of elevations of the
table land of, 408 ; volcano of,
402 ; considerations on the
mountain chains, 405. See also
New Mexico.

Mica, 473.

Micuipampa, mean annual tempe-
rature of, 41, 42.

Middendorf's two Siberian expe-
ditions, 43 ; on the frozen soil
of Northern Asia, 47.

Minchinmadom, volcano of, 290.

Mines, observations in, on mag-
netic dip and intensity, 116.

Mitscherlich on the minerals of the
Eifel, 235 ; on the melting point
of granite, 246.

Mofette-grottoes of Java, described
by Junghuhn, 220.

Momay, hot springs of, 197.

Momobacho, the volcano, 273.

Momotombo, the volcano, 274.

Monkwearmouth, the coal mine at,
37.

Mont Blanc, the Grand Plateau
of, 231.

Mont Pelvoux, the highest summit
of the French Alps, 230.

Monte del Diablo, in California,
416.

Moon, extent of our acquaintance
with the surface of the, 448;
volcanoes and parasitic craters,
449 ; magnetism of the Kreil
on the, 85 ; investigation of
the subject by General Sabine,
viii.

Mormons, Great Salt Lake of the,
410.

Mortero, Cerro del, 321.

Mosenberg, the, an extinct vol-
cano, 232, 238.

Mosychlos, the mountain, destruc-
tion of, 349.

Mouna Loa. See Mauna Roa.
Mountain masses, magnetism of,

159.
Mountain peaks, comparison of,

with the bulging of the earth's

surface, 28.
Mousart (corruption of Muztag),

equivalent to Sierra Nevada,

434.

Moya cones of Pelileo, 172, 216.
Mud-springs of Iceland, 212.
Mud- volcanoes, 217, 379.
Murchison, Sir R., on eruptive

trap masses, 350, 483.
Muriatic acid fumaroles, 424.
Mutis, apparatus of, 459.

Naphtha springs, 207.

Negropont. See Eubcea.

Neptune, connexion of, with earth-
quakes, 179.

New Britain, volcanoes of, 396.

New Caledonia, volcanic action
absent from, 398.

New Guinea, volcanoes of, 396.

New Mexico, barometric levellings
in, 407; list of heights, 408.

New Zealand, geology of, 396;
volcanoes, 397.

Niphon, recorded volcanic erup-
tions in, 374.

Nodes, magnetic, their changes of
position, 103. 106.

Noises from volcanoes, differences
observed in, 263 ; extraordinary
distances at which heard, 264.

Norman, Robert, determines the
inclination of the magnetic
needle in London, 57.

North-west America, volcanoes of,
403 ; hypsometry of, 408.

No variation (magnetic), points
ami lines of, 54, 58.

Obsidian, 479 ; its cavities and

airholes, 482.
Oeriifa, in Iceland, fearful erup»

tions of, 351.

INDEX.

495

Oeynhausen, temperature of the

salt spring at, 36.
Oisans, natural amphitheatre of,

its vast extent, 231.
Oligoclase, 471.

Olot, extinct volcanoes of, 433.
Olympus, Mount, in America,

418.

Omato, Volcan de, 286.
Ometepec, an active volcano, 273.
Orinoco, high temperature of its

waters at certain seasons, 186.
Orizaba, a volcano, measurement

of the peak of, 251 ; lava field

of, 3-24.
Oron, fresh-water lake of, seals

found in the, 437.
Orosi, the volcano, 273.
Orthoclase, 480.
Osomo, volcano of, 290.
Overweg's researches on volcanic

phenomena in Africa, 355.
Ovid, volcanic phenomena clearly

described by, 229.
Owhyhee. See Haivaii.

Pacaya, eruptions of, 276.

Pacific Ocean, the term "Grand
Ocean," improperly applied to
the, 404; comparatively small
number of active volcanoes,
388 , grouping of its islands by
Dana, 390. See also South
Pacific Ocean, South Sea.

Panguipulli, Volcan de, 290.

Papagayos, remarkable storms so
called, 271.

Paramos, their elevation and vege-
tation, 294.

Paramagnetism exhibited by oxy-
gen gas, 49 ; importance of the
discovery, 78, 82, 99.

Parasitic craters of the Moon,
449.

Parinacota, volcano of, 287.

Passuchoa, the extinct volcano of,
337.

Patricius, the bishop, his theory of
central heat, 196.

Paul, St., volcanic island of, 384.

Pele's hair, volcanic glass so called,
392.

Pelileo, eruption of the Maya of,
172,216.

Pendulum, vibrations of the, ap-
plied to determine the figure of
the earth, 1 9 ; Sabine's expedi-
tion, 22 ; other observers, 23 ;
the form of the earth not ex-
actly determinable by such
means, 25 ; Airy's experiments
at Harton, vii.

Pentland, his discovery of lava-
streams in the eastern chain of
the Andes, 295.

Perlite, 344.

Pertusa, hot springs of, 196.

Peru and Bolivia, series of voles-
noes of, 292.

Peshan, volcano of, 356, 434.

Peteroa, volcano of, 289.

Peterman's notices from Overweg,
of volcanic phenomena in Africa,
355.

Phaselis, flame of the Chimgera,
near, 212.

Philippines, volcanoes of the, 243.

Phlegreean fields, ancient descrip-
tions of the, 428.

Pic de Xethou, the highest sum-
mit of the Pyrenees, 230.

Pic of Timor, formerly an ever-
active volcano, 382.

Pichincha, remarkable form of,
241 ; ascent of, by Humboldt,
242 ; visited by Wisse, 242 ; its
height, 250.

Pichu-Pichu, Volcaii de, 286.

Pico, the volcano, 247 ; eruptions
of other volcanoes in the Azores
apparently dependant on, 351.

Piedmont, trembling of the earth
in, 183.

Pill a, on the leucite-crystals of
Kocca Monfina, 466.

Pisoje, basalt-like columns of,
456.

Pithecusse, Bokh on the, 266.

Pitt, Mo\mt, in America, 417.

Plato, on the Pyriphlegethon, 35,

40G

INDEX.

208 ; on the magnetic chain of
rings, 50.

Polar light. See Aurora.

Polarity, the force of, unknown to
the Greeks and Romans, 50.

Poles, magnetic, traditions regard-
ing, 55 ; Halley's variation
chnrt, 59.

Polybius, his knowledge of Stron-

gyle, 257.
oly

Polynesia and similar divisional
terms, objected to, 389.

Pomarape, volcano of, 287.

Popocatepetl, a volcano, 251 ;
meaning of the name, 239 ; de-
terminations of the height of,
458.

Porphyries of America, 475.

Porphyry of the Puy de D6me,
its peculiar character, 450.

Portobello, hot springs of, 193.

Pozzuoli, eruption from the solfa-
tara of, 423.

Procida or Prochyta, 265.

Proclus on earthquakes, 179.

Pulu Batu, lava-sti-eams of, 382.

Pumex Pompeianus, 430.

Pumice not found at Jorullo, 319;
abundant in Lipari, 340; the
pumice quarries of Lactacuuga,
342 ; of Cotopaxi, 343 ; isolated
eruptions of, 344 ; found in
Madagascar, 384 ; and in the
island of Amsterdam, 387; Hum-
boldt's view of its formation,
483.

Pumice eruption of the Eifel, 236.

Punhamuidda, volcano of, 290.

Pusambio, the river, acidified by
sulphur, 202.

Pyrenees, highest summits of the,
230, 231.

Pyriphlegethon, Plato's geognostic
myth, 35, 268.

Quelpaert's island, a volcano, 376.
Quesaltenango, Volcan de, 277.
Quetelet on daily variations of

temperature, 38.
Qaludiu. See Azufrol de Quindiu.

Quito, observations on the older
rocks of the volcanic elevated
plains of, 444.

Quito and New Granada, the
group of volcanoes of, 281.

Rainier (or Regnier) Mount, an
active volcano, 418.

Rains, regions of summer, autumn,
and winter, 188.

Raking of mountain chains ex-
plained, 294.

Rammelsberg's analysis of the
Chimborazo rock, 461.

Ranco, volcano of, 290.

Rapilli, 234.

Raton Mountains, extinct volca-
noes of the, 413.

Regnier, Mount, an active volcano,
418.

Rehme, the Artesian well at, 36.

Reich's experiments to determine
the density of the earth, 31; the
subject more lately investigated
by Airy, vii.

Results of observation in the tel-
luric portion of the physical
description of the universe, 8.

Revillagigedo, volcanic islands of,
281.

Ribbed formation of the volcanoes
of the island of Java, 303 ; ana-
logous phenomena of the mantle
of the Sornma of Vesuvius,
305.

Richer, observations on the pen-
dulum, by, 19.

Rigaud, Professor, on the propor-
tion of water and terra firm a,
388.

Riudjana, a volcano, its height,
881.

Riobamba, terrible earthquake at,
167, 172, 173.

Rio Vinagre, described, 202.

Rock-debris, 331.

Rocky Mountains, the chain de-
scribed, 411; traces of ancient
volcanic action, 414 ; parallel
coast ranges, still volcanic, 4 1 Jv

INDEX,

497

Ronquido and Iramido, distin-
guished, 263.

Rope-boricg of the Chinese, 219.

Rose, Gustav, his classification of
volcanic rocks, 449, 453.

Ross, Sir James Clark, his Ant-
arctic voyage, 75, 145.

Ross, John, his Polar voyages, 65.

Rucu-Pichincha, its meaning, 242.

Ruido, el gran, 172.

Sabine, Major- General, his pendu-
lum expedition, 22 ; on the
horary and annual variations,
82 ; on the influence of the
moon on terrestrial magnetism,
viii.

Sacramento Butt, an extinct
crater, 416.

Saghalin, called Krafto by the
Japanese, 367.

Bahama, Volcan de, 286.

Salses and naphtha springs, 207.

Salt Lake, Great, of the Mormons,
410.

San Bruno, rotatory motion of the
obelisks before the monastery
of, in Calabria, 172.

San Clemen te, volcano of, 290.

Sandwich Islands, a volcanic ar-
chipelago, 391 ; the volcanoes,
245 ; height of some greatly
exaggerated, 250.

Sangai or Sangay, the volcano,
251 ; its position, 251 ; the most
active of tho South American
volcanoes, 262; its eruptions
observed by Wisse, 182.

Sanidine, 475.

San Miguel Bosotlan, a volcano,
275.

San Pedro de Atacama, Volcan de,
287.

San Salvador, a volcano, eruptions
of, 275.

Santa Cruz, volcano of 395.

San Vicente, a volcano, eruptions
of, 275.

Santorin, volcanic eruption of,
229.

VOL. V.

I Saragyn, hot springs of, 346.

Sawelieff on magnetic inclination,
113.

Schagdagh, the perpetual fires of
the, 210.

Schergin's shaft, at Jakutsk, 43.

Schiwelutsch, a volcano, its pecu-
liar form, 248

Schlagintweits, the brothers, ob'
servations on springs, 191; tra
verse the Kuen-lun, 439.

Schrenk, on the frozen soil in the
country of the Samojedes, 46.

Sea, distance of volcanic activity
from the, statements of, exa-
mined, 432 ; volcanic eruption
observed in the, 377

Seals found in the Caspian Sea,
and the Sea of Baikal, 437; also
in the distant fresh-water lake
of Oron, 437.

Secular variation of the magneti
inclination, 111.

Semi-volcanoes, 424.

Senarmont, his preparation of
artificial minerals, 204.

Seneca on volcanoes, 226.

Sesaya, volcano of, 395.

Shasty mountains, basaltic lavas
found in the, 416.

Siebengebirge, trachyte of the,
237 ; geological topography, 454.

Siebold on the volcanoes of Japan,
373.

Sierra Madre, erroneous notions
regarding the, 405, 410 ; east
and west chains, 410.

Silla Veluda, volcano of, 289.

Silurian and Lower Silurian for-
mations, eruptive trap masses
of the, 350, 483.

Silver in sea-water, its presence
how manifested, 440.

Sitka or Baranove, 43, 269.

Smyth, Capt., on the Columbretes,
350 ; determination of the
height of Etna, 249.

Society Islands, the geology of,
recommend***! for investigation,
399.

2K

498

INDEX.

Soconusco, the great volcano of,
277.

Soffioni,the, of Tuscany, 211.

Soil, frozen, in Northern Asia, 42 ;
its geographical extension, 47.

Solfatara, the term inapplicable
to the crater of Kilauea, 392.

Solo islands, character of the, 378.

Solomon's islands. See Sesarga.

Soufriere de la Guadeloupe, the,
described, 423.

South Pacific Ocean, great num-
ber of volcanoes of the, 431.

South Sea, volcanoes of the, 388 ;
its islands incorrectly described
as scattered, 389 ; the term
"Grand Ocean" objected to,
404.

Southern Asia, volcanoes of the
islands of, 377.

Spain, extinct volcanoes of,
433.

Spartacus and his gladiators, their
encampment on Vesuvius, 427.

Special results of observation in
the domain of telluric pheno-
mena, 1.

Springs, rise of temperature in,
during earthquakes, 175 ; diffi-
culty of classifying into hot and
cold, 185 ; method proposed,
185 ; considerations on tempe-
rature, 187; heights at which
they are found, 190; boiling
springs rare, 197; the Geysirs
and Strokkr, 198; gases, 201;
Hallmann's classification, 205 ;
vapour and gas springs, salses,
207.

Stokes, on the density of the
earth, vii.

Stone streams distinguished from
lava streams, 306.

Strabo, on the figure of the earth,
27 ; on lava, 226 ; on a double
mode of production of islands,
265.

Strokkr, the, of Iceland, described,
199.

Stromboli, description of, 256;

periods of its greatest activity
257.

Strongyle, described by Polybius,
257.

Strzelecki, Count, on the basin of
Kilauea, 393.

Styx, the waters of, 203 ; visits to
their source, 203.

Submarine volcano, presumed, in
the Atlantic Ocean, 353 ; one
observed in the Pacific near
Chiloe, 288.

Subterranean noises, 178 ; at-
tempts to determine the rate of
their transmission, 179.

Sulphur Island, described by Cap-
tain Basil Hall, 377.

Sulphuretted hydrogen, question
as to its existence in certain
fumaroles, 425.

Sumatra, the Giava Minore of
Marco Polo, 379.

Sumbava, violent eruption of the
volcano of, 381.

Sun, magnetism of the, 85.

Sunda islands, volcanoes of the,
380, 381.

Swalahos, Mount, an extinct vol-
cano, 417.

Taal, active volcano of, its sin-
gular position, 243; small ele-
vation, 244.

Table-land of South America, of
Mexico, and Thibet, 406; list
of elevations, 408.

Tacora, Volcan de, 286.

Tafua, the peak of, 398.

Tahiti, the geology of, recom-
mended for investigation, 399.

Tajamulco, the volcano of, 277.

Taman, mud volcanoes of the pen-
insula of, 217.

Taranaki, a volcano in New Zea-
land, 397.

Taurus, elongated, theThian-schan,
inchiding the Himalayas, known
as the, to the Greeks, 434.

Tazenat, Gouffre de, an extinct
yolcano, 238.

499

Telica, Volcan de, described, 274.

Telluric phenomena, special re-
sults of observation in the do-
main of, 1.

Temboro, a volcano, its violent
eruption, in 1815, 381.

Temperature, invariable, stratum
of, 39 ; mean annual, how de-
termined in the tropics, 40;
observations of, in Mexico and
Peru, by Humboldt, 41 ; frozen
soil in Northern Asia, 42;
Schergin's shaft, 43. See Interior
of the Earth.

Temperature, rise of, in springs,
during earthquakes, 175.

Teneriffe, the felspar of the tra-
chytes of, 457; notice of an erup-
tion on, by Columbus, 477.

Ternate, violent eruptions and
lava streams in, 381.

Tertiary formations in Java, 298.

Thermal springs, their connexion
with earthquakes, 177.

Thian-schan, the volcanic moun-
tain chain of, 358 ; peculiarity
of the position of the volcano,
433 ; the chain known to the
Greeks as the elongated Taurus,
434.

Thibet, hot springs of, 197; gey-
sir, 199.

Tierra del Fuego, volcanoes of,
296.

Timor, Pic of, formerly an ever-
active volcano, 382.

Tollo, the pumice hill of, 481.

Tonga Islands, active volcanoes of
the, 394.

Toronto, magnetic observations
at, 100.

Trachyte, origin of the word, 450;
frequently used in too confined
a sense, 452; further remarks,
468.

Tractus chalyboeliticos, what, 59.

Translatory movements in earth-
quakes, 173.

Trap, masses of, Sir R. Murchison
on, 350, 483.

Trass, formation, 236.

Trincheras, hot springs of, 197.

Tristan da Cunha, a volcanic
island, 353.

Tshashtl mountains, basaltic lavas
of the, 416.

Tucapel, volcano of, 289.

Tupungato, measurement of the
peak of, 289.

Turbaco, the Volcancitos of, 213.

Tuscan Maremma, volcanic pheno-
mena of the, 211.

Typhon, fable of, 266.

Umnack, volcanic island of, 230.

Unalavquen, volcano of, 290.

Under currents of cold water in
the tropics, 194.

United States' scientific expedi-
tions, benefits to natural history
from the, 404.

Uvillas or Uvinas, Volcan de, 286.

Val del Bove, on Etna, remarkable
inference regarding, 225.

Valleys of elevation, what, 201.

Vancouver, Mount, 417.

Vapour and gas springs, 222.

Variation charts, their early date,
54.

Vegetation, limit of. in Northern
Asia, 43.

Vesuvius, phenomena of an erup-
tion of, as observed by Hum-
boldt, 181; barometrical mea-
surements by the same, 247 ;
lengthened series of eruptions
of, 426; described by Strabo,
426; by Dio Cassius, 427; by
Diodorus Siculus, 428 ; by
Vitruvius, 428 ; difference of
constitution of the old and the
recent lavas, 477 ; encampment
of Spartacus and his gladiators
on, 427.

Vesuvius, valley furrows on the
mantle of the Somma of, 305.

Vidua, Count Carlo, his melan-
choly death, 381.

Vilcanoto, peak of, 296.

500

INDEX.

Villarica, Volcan de, 290.

Vincent, St., the volcano of, 422.

Vincent of Beauvais, his mention
of the magnetic needle, 53.

Virgenes, las, extinct volcanoes in
Old California, 416.

Vitruvius, notice of Vesuvius by,
428.

Vivarais, extinct volcanoes of the,
278.

Volcan Viejo, a crater in Southern
Peru, 286.

Volcancitos of Turbaco, described,
213.

Volcanic districts, different aspects
presented by, 224.

Volcanic islands in the South
Atlantic Ocean, 353.

Volcanic reaction, bands of, 176.

Volcano, what intended under the
term, by Humboldt, 287.

Volcano, the island styled "the
holy isle of Hephsestos," 257.

Volcanoes, considered according
to the difference of their forma-
tion and activity, 224 ; definite
language of modern science,
228 ; number of, on the earth,
421 ; their great number in the
Eastern Archipelago, 379 ; hyp-
sometry of, 246 ; linear arrange-
ment of, 268; table of dif-
ferences in structure and colour
of the mass in certain, 463 ; the
Mexican system, 279 ; sequence,
latitude, and elevation, 281 ;
particulars of the five groups of,
in the New Continent, 285 ;

list of active, 277 ; geography of
active, examined, 349 : geogra-
phical distribution of, 430; open
in historical periods, list of, 35 1 ;
semi-volcanoes, 424.

Volcanoes of the moon, 448.

Vulcanicity, definition of, 163.

Wales, volcanic phenomena in,
350.

Walferdin on Artesian wells, 35,

Waltershausen, his classification
of the volcanoes of Iceland,
351 ; remarks on the period of
recurrence of eruptions in
various volcanoes, 255, on the
trachytes of Etna, 465.

Wilkes, Captain, commander of
the American expedition, 105,
388.

Wislizenus, positions in North-
West America ascertained by,
408.

Wisse, his observations of the
eruptions of the volcano of
Sangai, 182; 264; his visit to
Pichincha, 242.

Yana-Urcu, a volcanic hill, 193.
Yanteles (Yntales), volcano of,
290.

Zapatera, extinct crater of the

island, 273.
Zohron, the southern pole of the

magnetic needle, 53.
Zone of volcanic activity, 176.
Zuni, petrified forest near, 414.

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