UC-NRLF

SB 527 012

THE LIBRARY

OF

THE UNIVERSITY
OF CALIFORNIA

PRESENTED BY

PROF. CHARLES A. KOFOID AND
MRS. PRUDENCE W. KOFOID

THE WORLD:

OR

FIRST LESSONS

IN

ASTRONOMY AID G-EOLOGY,

SN CONNECTION WITH THE PRESENT AND PAST CONDITION OF

'OUR GLOBE,

BY HAMII/rOH L,. SMITH, A. M.

!LL- LIMESTONE, FROM THE MOUTH OF THE THAMES.
(From MantelVs Medals of Creation)

" The World is God'g Epistle to Mankind."— Plato.

CLEVELAND:
M. C. YOUNGLOVE AND COMPANY.

1 848.

.0

Entered according to Act of Congress, in the year 1848,

BY HAMILTON L. SMITH,
In the Clerk's Office of the District Court of the District of Ohio.

34,7

PREFACE.

THE importance of the sciences of Astronomy and Geology,
is acknowledged by every one. Few, however, find sufficient
leisure to bestow upon these subjects much attention. They look
upon the ponderous tomes which men of science have from time
to time prepared, with a sort of indifference, as too learned for
them. And yet, show any of these, a curious star in the
heavens ; tell them of the wonders revealed by the telescope; ex-
hibit to them, the impression of a fish in sandstone, or chalk; or
show them through a microscope, the curious and distinctive
structure of fossil teeth, or the infusoria in a fragment of flint ;
and they will give willing attention. Since, then^ the subjects
themselves are so interesting, so profitable, and withal harmless,
we have endeavored — with what success will hereafter appear —
to supply a desideratum long felt. The object of the present
volume is to present in a popular manner, so much of Astrono-
my, Meteorology, and Geology, as seemed desirable for everyone
to know. While no pretensions are made to scientific accuracy,
yet it is believed that the book will be found worthy of an atten-
tive perusal. There is little to be gained by merely glancing here
and there at a page; the knowledge thus obtained, if any, will be
small, and soon lost. The attentive reader will, if the book be
worth perusing at all, find sufficient to amply repay for the time
thus spent. It should hardly be necessary for any one at this late
day, to offer an apology in behalf of Geological studies, because
of the fancied contradictions to the Mosaic chronology. Writers on
this subject heretofore, have spent no little pains, in what we may
well term, endeavoring to "make darkness visible." So apolo-
gies were once offered fof Astronomy, when that noble science
taught the diurnal and annual motions of the earth. We have
felt called upon to make no such apology, but simply to state the

VI PREFACE.

facts, well convinced that true philosophy and religion go hand in
hand, and that if "an undevout astronomer is mad,'* so must be
an undevout geologist How vast, and how ennobling the ideas
of Creative Power and Wisdom, which these sister sciences af-
ford. The mind is overwhelmed by the immensity of creation,
whether it strives to reach beyond the faintest and fartherest star
yet discovered through optic glass, or whether it endeavors to
reckon the years elapsed since the first granite rocks upreared
their rugged steeps amid the primeval waters. Though we have
gazed for whole nights at those dim streaks of nebulous matter in
the heavens, at the planets, and revolving stars, when there were
companions with us, no longer upon earth ; and though we have
split open the sandstone shales, and picked out the fossil shells, and
looked for hours at little fragments of fossils through the micro-
scope, we do not feel our time as wasted, or wholly spent in vain,
if we may be the means of communicating to others a knowledge
of these pleasant subjects. However imperfect the execution of
our work may be, yet to it we have given long and patient atten-
tion. We cannot claim much merit for originality. Among the
host of scientific men whose lives have been spent in original in-
vestigations, it would be strange could we not find better illustra-
tions than our own ; we are still but learners.

Should the present attempt to produce a popular work upon
Astronomy and Geology prove successful, it is anticipated follow-
ing it up with a volume upon the planets and stars ; for in the
present, only so much of Astronomy is presented as is necessary
to understand the motions and general phenomena of our earth
The chapters on fossil remains are not as many as might seem
desirable; perhaps we may more perfectly and fully review the
same subjects hereafter in another volume.

It is but right to say that the engravings have all been executed
in this city by Mr. J. Brainerd; and when we add that they are
not from transfers, but from pencil drawings, they will be ac-
knowledged as very creditable specimens of the artist's skill.

Cleveland, August, 1848.

•INTRODUCTION.

IT would be difficult for us to name a study more interesting
than a history of the Earth, past and present ; for by a peculiar
and distinct chain of causation, it unites the present with the re-
mote past ; constantly urges us to look for the beginning of that
state of things we have been contemplating; conducts us to the
boundaries of physical science, and even gives us a glimpse of
the regions beyond.

The Astronomer looks upon the heavens as the type of eternity
and immortality. The crystal spheres and orbs which he once
imagined to exist, are, so far as stability and uniformity are con-
cerned, now no longer necessary. A few simple motions, results
of one law, controled by one Power Divine, sustains the mighty
fabric. The Geologist looks upon the heavens and upon the
earth as but everlasting; he comprehends that a thousand changes
may come aver them, while still they move in their grand circles.
To him the present configuration of land and sea is but one of the
many changes through which the globe has passed, and he is
prepared to admit that the whole human race may be swept away,
and a new creation succeed ; — such catastrophes have occurred.
We ask in vain, whether other worlds are inhabited 7 no voice
comes from those distant orbs to tell us of life , no eye can pene-
trate so far; we turn then with a renewed zeal to study " the sci-
ence of the changes which have taken place in the organic and
inorganic kingdoms of nature," as developed on the surface of
our own planet. The beginning; where shall the beginning be ?
We endeavor in vain to penetrate the almost sepulchral stillness
and darkness of the primeval world, and trace with certainty the
origin of things. All that we can possibly know is the simple

VU1 INTRODUCTION.

truth — "In the beginning, Jehovah created the heavens and the
earth." Certainly there was a day — Geology demonstrates this
— when nothing but barren rock and wide spread waters covered
the globe. Who but Jehovah called into being the successive
races of animal and vegetable life, which have flourished and
died ? Whose eye but Jehovah's has seen the myriads of revo-
lutions* during which the immense fossil-bearing beds were de-
posited ? We cannot comprehend these things;

"Our noisy years seem moments in the being
Of the eternal silence."

The granite pebble which we roll over, heedless and careless,
is older by millions of years than the first created of our race; and
when was that being created ? Questions like this, we are forced
to say, we can no more answer, than we can tell the form, and
number, of the inhabitants of the evening star.

"But though philosophers have never yet demonstrated, and
perhaps never will be able to demonstrate, what was that primitive
state of things in the social and material worlds from which the
progressive state took its first departure ; — they can still, in all
the lines of research, go very far back ; — determine many of the
remote circumstances of the past sequence of events ; — ascend
to a point which from our position at least, seems to be near the
origin ; — and exclude many suppositions respecting the origin it-
self." And this is the boundary of human knowledge.

TABLE OF CONTENTS,

PART I.

CHAPTER I.

Page.

Rotundity of the Earth — Apparent motion of the Sun — An-
gles— Measurement of a Degree, - 13

CHAPTER II.

Apparent motions of the Planets— Ptolemaic -System —
Measurement of Angles — Diurnal revolution of the Earth
— Copernican System — Phases of Venus — Religion and

Philosophy, 25

CHAPTER III.

Parallax-2-Measurement of Distances — Distance of the
Moon, how determined — Distance of the Sun — Immensi-
ty of Creation, -------- 39

CHAPTER IV.

Time — Dials and Clepsydra— Siderial Day — Transit Instru-
ment— Geology and Astronomy, - 45

CHAPTER V.

The Calendar— Length of the Year—The Ecliptic— Preces-
sion of the Equinoxes — Julian Calendar — Gregorian Cal-
endar, .......53

CHAPTER VI.

Right Ascension and Declination — Sun Dials— Dialing — Di-
als and Clocks, - - - 67

CHAPTER VII.

Measurement of Time — Equation of Time — Longitude —
Quadrant— Method of determining apparent Time, - - 77

X CONTENTS.

CHAPTER V11I.

Page

Chronology — Revolution of the Pole of the Ecliptic — Preces-
sion of the Equinoxes — Egyptian Zodiacs, - - - 87

CHAPTER IX.

Signs of the Zodiac — Line of the Apsides — Change of the
eccentricity of the Earth's Orbit, - - - 97

CHAPTER X.

The Seasons — Declination of the Sun — Equinoxes — Divi-
sion of the Earth into five Zones — Sun's Path, - - 105

PART II.

CHAPTER I.

Meteorology — Indications of the Weather — Barometer —
Density of the Air — Pressure of the Air — Caswell's Bar-
ometer, - - - „-•- . . . 115

CHAPTER II.

Winds— Temperature of Valleys— Trade Winds— Mon-
soons— Hurricanes — The Sirrocco — The Harmattan — The
Simoon, - - - - - - - - - 125

CHAPTER III.

Clouds and Dew — Formation^ Clouds — Various kinds of
Clouds— Table Mountain, - - - - - 137

CHAPTER IV.

Climate — Distribution of Heat upon the Earth's Surface —
Different Lengths of Days — Thermometer — Isothermal
Lines — Effect of Climate on Plants and Animals — Table
of Temperatures, - - •- - •_ - 147

CHAPTER V.

Optical Phenomena— Color of the Atmosphere— Halo— Mi-
rage— Meteoric Showers — Zodiacal Light — Aurora Bo-
realis, - - .*-.--- 159

CONTENTS.

PART III.

CHAPTER I.

Page.

Structure of the JSarth — Probable Thickness of the Earth's
Crust — Extent of Surface — Simple Substances — Minerals
— Stratified Rocks — Succession of Strata, - - - 177

CHAPTER II.

Chronological Arrangement of Strata — Fossiliferous Strata
— Tertiary System — Secondary Formations — Unstratified
Rocks — Geological Names — Ideal Section of the Crust of
the Earth, 187

CHAPTER III.

Aqueous Causes of Change — Action of Running Water —
Sediment deposited annually by the Ganges — Excavation
of a Lava Current — Fluviatile Formations — Peat Bogs, - 197

CHAPTERIV.

Springs — Artesian Wells — Calcareous Springs — Incrusta-
tions and Petrefactions — Silicious Springs — Salt Springs —
Subterranean Springs, - - - 207

CHAPTER V.

Currents — Gulf Stream — Oceanic Currents, Chart of — Ef-
fect of the Ocean upon Coasts* — Encroachments of the
Sea— Reculver Church— The Bore, - - - - 221

CHAPTER VI.

Volcanoes, Distribution of Line of Volcanic Vents —

Rocky Mountains— Isolated Volcanoes, - 235

CHAPTER VJI.

Volcanic Eruptions — Destruction of Pompeii — Eruptions of
Vesuvius— Of Etna— Of Hecla— Of Skapta Jokul— Vol-
canic Islands — Eruption of Jorullo, .... 343

CHAPTER VIII.

Earthquakes, Phenomena of — Extent of Country Agitated—-

Xii CONTENTS.

Page.

Gradual Elevation of Coasts — Temple of Jupiter Serapis
—Elevation of Coast of Sweden — Earthquake in Cala-
bria— In Peru, - - - . - - - . . 357

CHAPTER IX.

Atmospheric Causes of Change — Sand Floods — Dunes-
Chemical Influence of the Atmosphere — Disintegration of
Granite, 271

CHAPTER X.

Vital Causes of Change— Coral Animalcules — Brain-stone
Coral — Madrepores — Appearance of Living Corals, - 279
CHAPTER XI.

Coral Islands — Atolls — Barrier and Fringing Reefs — Whit-
sunday Island — Bolabola — Formation of Atolls and Bar-
rier Reefs, • - - -287

CHAPTER XII.

Organic Remains — Infusoria in Flint — Age of the Earth —
Minerals and Fossils — Imbedding and Preservation of Or-
ganic Bodies — Division of the Animal Kingdom, - - 295
CHAPTER XIII.

The Granitic Period — Basaltic Columns — Fingal's Cave —
Graptolites— Encrinites— Trilobites— Fossil Fishes — Ferns
— Fossil Crustaceans— The Belemnite— Flora of the Oolitic
Period— Pterodactyle— Close of the first Epoch, - - 302

CHAPTER XIV.

Commencement of the second Period — Fossil Foot-steps —
. The Labyrinthodon— Dinornis — Plesiosaurus— Ichthyosau-
rus—Close of the second Epoch, 310

CHAPTER XV.

The Tertiary or third Period— Character of the Deposits-
Fossil Remains — The Deinotherium — Mammoth — Mas-
todon— Elephant — Megatherium— Irish Elk — Close of the
last Epoch, 319

THE WORLD.

CH APTE R 1.

Figure of the Earth.

*' And still, as sunk the golden Orb of day,
The seaman watched him, while he lingered here,
With many a wish to follow, many a fear,
And gazed, and gazed, and wondered where he went,
So bright his path, so glorious his descent." — Rogers.

THE constant and regular sucwssion of day and night, is the
first great phenomenon which arrests our attention, when we com-
mence a study of nature. Day after day, we behold the sun, after
a definite and well determined period, rising in the east, and as-
cending the heavens; and no sooner has the blazing orb sunk
beneath the western horizon, than we raise our eyes to the blue
vault, expecting and beholding the placid stars.

Doubtless, the first impression is always, that we are at rest, and
that the sun, and all the stars of heaven, are slowly, and'forever,
revolving around us.

A thoughtful consideration of the phenomena which attend the
regular return of day and night, will soon convince us that this
conclusion is erroneous, and will point out to us the true solution
of the grand problem.

Let us go upon some eminence when evening draws near, and
watch the successive changes which usher in the night. The red
orb of the sun, shorn of his lustre, his ruddy beams scarce pene-
trating the mists which creep over the surface of the earth, sinks
gradually beneath the wave, or distant hills; a ruddy glow illu-
mines the western sRy,

*' Twilight's soft dews steal o'er the village green,"
slowly the light fades away, fainter and fainter, giving place to

14 THE WORJL1). '

serene night, and now the stars, which the brilliancy of day had;
eclipsed, shine forth in all their splendor, and perhaps that fairest
one of them all, the evening' star, adorns the western sky. As
we look over the heavens, we notice here and there a group, or as
the astronomer calls them, a constellation, with which we have
been familiar from childhood. If we look upon the winter sky,
we recognize Orion, with his bright belt, and the Pleiades or seven
stars, or turning to the north, the great dipper or Charles' wain,
being a part of the constellation " Ursa Major," or the " Great
Bear." As the eye wanders over these familiar objects, another
sight bursts upon the delighted vision. The full-orbed moon rises
majestically over the eastern hills, and in the increasing light,
the lesser stars fade away. The evening star, no longer brilliant,,
is now ready to set below the western horizon, and stars, which at
the commencement of night, w%re to the east of the meridian, are
now in the mid heaven. If we turn to' the north we find a change
there, the cluster or group called the dipper, which we will sup-
pose, at the commencement of our observation was almost
parallel with the horizon, as shown in this figure, has moved

eastward, and evidently performed a part of a revolution aboni
some unknown centre. If we prolong our observations we find
this group, and all the rest of the heavens apparently revolving
around one star, which seems not to move at all. This star is
called the pole, or polar star, and is nearly m. a line with the two
bright stars at the end of the dipper as shown at a and b in the
above diagram, and about five times their distance, from the nearest
one. Meanwhile, the lunar orb, with all its beautiful diversity of

ROTUNLHTY Ol- THE EAKTH. lO

light and shade, ascends the heavens, reaches the highest point
and declines in the west. Star after star sinks beneath the
western hills, and new ones rise in the east. Twelve hours pass
away, when again the sun, rising with undiminished lustre, calls
the busy world once more into bustle and activity.

The phenomena thus presented, convince us that there is no
such thing as rest, for the whole heavens seem revolving around
us, and the first step towards an accurate knowledge of our earth
is, that either we, or the heavenly bodies, are in ceaseless and
regular motion.

Suppose that before us the waters of some vast lake or ocean
are spread out ; far as the eye can reach the're seems to bo a place
where the sky is resting upon the water, called the horizon from
a Greek word meaning "to see." As we stand, perhaps won-
dering how far from us this horizon is, a vessel sails out the harbor
and moves steadily from us. Now our first idea is that we are
looking out upon a vast plain, and consequently .we expect to see
the vessel as it moves away, become fainter and fakiter, until at
I ast the straining eye will fail to catch the minute image. This
appearance is shown in the engraving below.

Instead of this, however, a new and unexpected phenomenon
greets the eye. The vessel sails away, and soon arrives at the
horizon, and then slowly sinks from view. First the hull disap-

16 THE WOULD . ,

pears, then the sails;" and at last the flag, presenting the appearance
shown in this engraving.

This then is the second step towards obtaining an accurate
knowledge of our earth, and we learn that the surface of our
lakes, and seas, is not an extended plain, but curved. If we were
on a vessel at sea, we would perceive the horizon encompassing us
like a vast circle, of which, we would be the centre. And in
whatever direction we made an observation, we would find the
surface of the water curving or bending from us in that direction.
The same phenomenon is observed on land. If we ascend some
high elevation, such as a mountain, or lofty monument, the horizon
appears in every direction equally distant, or, in other words, a
large circle, of which we are the centre. From this we rightly
. infer that the surface of the earth is convex, like the surface of an
apple, or an orange. It becomes an interesting question, after
the convexity of the earth is thus established, to determine its actual
shape, whether it is a true sphere, or spheroide, i. c., having the di-
ameter through one direction longer than another, or, whether the
curvature is of such a nature as to return into itself, for it is well
known that there are curves, such are the parabola, and hyper-
bola, which, however far continued, never return into themselves
like the curve of a circle. It was therefore a bold undertaking to
circumnavigate the globe and thus demonstrate its spherical form,
by actually sailing around it. This was accomplished however
by Ferdinand Magellan, or rather by the expedition which he fitted

ROTUNDITY OF THE EARTH. 17

out, for he himself did not live to witness the complete triumph
of his bold attempt. Magellan was a Portuguese who had entered
into the service of Spain. In the year 1519 he sailed for South
America, and discovered the straits called by his name, and
which separate the island of Terra del Fuego from the continent.
He likewise discovered the Marian and Phillipine islands, which
_he took possession of in the name of the King of Spain, and was
killed on one of the latter group. His fleet was mostly dispersed,
but one ship with eighteen men, returned'to Spain in 1522, having
sailed westward completely around the world. The rotundity of
the earth, by these means, was established beyond a doubt, though
indeed this proof was not necessary, a great variety of phenomena
giving the same result. For example, the shadow of the earth,
which is cast upon the moon at the time of a lunar eclipse, is
always bounded by a curved line or circle, and it can be shown
mathematically, that a spherical form is absolutely necessary for
the stability of the earth. The moon, and all the planetary bodies,
are also observed to present discs, the same as a ball suspended in
the sky. Having learned these two things, viz : that there is a
great and unceasing motion somewhere, and that the earth is
j-ound, it becomes interesting to determine its actual size, its
diameter and circumference. Previous to determining this and
on the supposition that our earth is the grand centre of the uni-
verse, let us study the phenomena presented by the sun, plan-
ets, and stars in their apparent diurnal or daily revolution around
the earth, premising however, that to certain directions upon its •
surface the arbitrary names, North, South, East, and West, have
been assigned. For example, we call the part towards the north
star north, the opposite south, and facing towards the north star,
we call the right hand east, and the left hand west. These names
are entirely arbitrary, i. c., they do not actually represent fixed
directions in space, but are simply relative expressions, thus, what
is east to one observer, may be west to another, for example, take
the next diagram, representing the earth as round, the north pole
being at the position N, and suppose two observers one at A, and
the other at B, both facing towards the north.

If questioned about some object C, B would declare it to be

18

THE WORLD.

west, being at his left hand, whilst A would assert it to be east,

C

being at his right hand. The terms therefore, north, south, east
and west, are only relative expressions, and not absolute direc-
tions. It will be necessary to remember this, and we may also
remark, the same is true of the expressions up, and down. What
would be up to an observer at A, would be in the direction N A,
but this would be down to an observer at B. Hence we must
learn to consider up, as away from the earth, and down as the
direction to its centre, and therefore not absolute directions in
space but only relative terms. Now as the sun and the stars are
observed after certain regular intervals to appear in the east,
apparently move over the heavens, and set in the west, the natural
inference is, that they are revolving in vast circles around th^
earth, which itself is the immovable centre. Below we have given

an engraving which represents the earth as the centre, and the

MOTION OF THE SUN. 19

sun revolving around it in a circular orbit, and the stars still fur-
ther beyond. Now on the supposition that this is the true system
of the world, suppose the suii revolving in the direction A B, and
an observer at a, facing towards the north N. He would perceive
the sun appear to rise at his right hand, or in the east, and when
the sun had travelled far enough round, say to B, to become
visible to an observer at b, he would see it at his right hand, or hi
the east. The sun in his daily revolution, would thus track out in
the heavens a certain line, which astronomers call a diurnal circle.
Now suppose that some morning, just at sunrise, we observe
a particular star, A, close to the sun, rising just before it. If the
stars revolved around the earth in the same time as the sun, as
they seem to do from a casual observation, it is evident that after
any definite interval, say one month, the sun and this star would
still be found together, but this is not the case, for after one month,
it will be found, that this star A, which rose just before the sun,
will now rise two hours before him, and the sun will be near the
star C, having apparently moved backward the distance A C. If
we should continue to observe this backward motion of the sun,
we would find that after one year had elapsed, the sun would have
moved completely around backward, contrary to the direction in
which, each day he seems to move across the heavens, arriving
again at A. Hence it would appear, that, the earth being the
centre, the stars are revolving around it a little faster than the sun,
but in the same direction, gaining upon the sun about 4 minutes
a day, so that in one month the star A would gain 120 minutes or
two hours, and rise just so much sooner than the sun ; and thus,
in the course of a year, the stars would make one more revolution
than the sun. Now suppose we were to observe carefully the
stars near and over which the sun passed in this backward motion,
for it is evident that this path would mark out a circle in the
heavens. Astronomers have done this, and they call this path or
line, which has a fixed position among the stars, the Ecliptic, or
sun's path. On the next page we represent the ecliptic, and a certain
space on each side of it. This space includes the orbits of all the
planets, which also partake of the same backward motion as the.sun.

90 THE WORLIK

nat moving- on uniformly with the stars. The middle bla,ck line

represents the ecliptic and the whole space or belt is called the
Zodiac. The ancients divided the zodiac into twelve equal parts,
and gave them names, indicative of the peculiar employment of
that season of the year, when the sun happened to be in any one
of them. For example, the sun, in the preceding diagram, is in
the sign called Virgo, or the Virgin ; this sign was represented
by a virgin bearing sheaves of wheat, as the sun was near these
stars in the fall of the year, when the harvest was gathered. We
shall refer to this again when we explain the phenomena of the
seasons. The ecliptic was divided into twelve parts, or signs,
because the moon makes the complete circuit in one-twelfth of
the time the sun does, hence the twelfth of the year is called a
moon, or a month. The time of a lunation,, or interval from new
moon to new moon, being thirty days, and twelve of these luna-
tions happening In a year, the number of days to the year, when
reckoned by lunar months is 360. This number of days however
Is not strictly correct, for the sun makes 365^ revolutions appa-
rently, around the earth, while moving from any particular
star around to that star again. It would be inconvenient to sub-
divide the ecliptic into 365 parts as this number cannot be halved,
or quartered. So the early astronomers, adopting the lunar year,
divided the whole circle into 360 parts, which they called degrees.
This division, it will be understood from what we have said, was-

ANGLES. 21

perfectly arbitrary. The circle might have been divided into just
100, or 1000 parts, and these called degrees, but it was convenient
to adopt for the length of a degree, a space which would represent
the progress of the sun in one day as nearly as was possible.
When we speak of a degree, it must be remembered that an
absolute length is not meant, but only the 1-360 part of some
circle. The length which belongs to a degree will vary with every
different circle. Thus in this diagram, we have two circles with

a common centre, and two lines drawn from that centre, including
20 degrees of each circle.

All circles are supposed therefore, to be divided into 360 parts,
and the 1-360 part of any circle is called a degree. Two kinds
of circles are supposed to be traced on the earth, as also in the
heavens, viz, great and small circles; this name does not arise
from the fact that one circle is actually greater than another, the
distinction is more marked, and is this —

Let A B C D, &c,, represent the earth, and let GC be a circle

22 THE WORLD.

the plane of which passes directly through the centre of the earth;
this is a great circle. So is A E for the same reason, for if the
globe were to be divided through these circles it would be exactly
halved, but a circle passing through H B, orF D, is called a small
circle, since the plane of the circle does not pass through the centre
of the sphere on which the circle is drawn. From this definition
it will be perceived that the circle A I E K, (the part behind the
sphere being shown by the dotted line) is a great circle, because
the plane of this circle passes through the centre of the sphere.
Every great circle, has what is called a pole, that is, a point ninety
degrees, or one quarter of a circle, distant from it in every direc-
tion, thus — A is the pole of the circle G C, for from whatever
point on the circle G C, the distance is measured up to A, it will
be found 90°. For instance the arcs' A G, A I, A O, A K, A C,
are all £ of their respective circles. Now suppose the circle G
C, to represent the equator, then A will be the north pole of the
earth, and E the south pole. Suppose now this great circle which
we have called the equator to be actually traced around the earth
and divided into 360 parts called degrees, marked (°), and sup-
pose these degrees subdivided into minutes marked ('), and call
these minutes miles, how many miles would the earth be in cir-
cumference? Evidently sixty times 360, or 21,600 miles. This is
not so much as the circumference is usually stated to be ; viz,
24,000 miles, and for this reason ; the mile at the equator, is longer
than the English statute mile. Referring to the preceding figure,
it will be readily perceived that if the circle fl B was divided
into 360 parts and these again subdivided into 60 parts each,
called miles, these miles would be much smaller than the equa-
torial miles, indeed it would require 69| English statute miles to
constitute 1°, or 60 equatorial, or geographical miles. Now if
we take 69 \ miles for the length of a degree, it is evident the
circumference of the earth will be 360 times this, or 25,020 miles,
and as the diameter is a little less than £ the circumference, the
diameter is called in round numbers 8000 miles. When there-
fore we assert that the earth is 8000 miles in diameter, we mean
simply this, if the equator, or any great circle drawn upon the

MEASUREMENT OF A DEGREE. 23

earth, is divided into 360 parts, and these subdivided into sixty
parts each, and their length ascertained, that it would take 8000 of
them to measure the diameter of the earth. The length of a mile
therefore, instead of determining the diameter of the earth, or its
circumference, is itself determined by that diameter or circum-
ference. The circle might have been divided into 1000 parts, and
these subdivided into 100 each, this would give 10,000 minutes
or miles for the circumference, but the mile in this case would be
shorter. Having assumed the earth's circumference 24,000 miles,
we next desire to know when we have passed over a mile on its
surface. This would seem a difficult undertaking at first thought,
for how can we determine when we have passed over a degree
upon the earth ? A diagram will explain the manner this is

accomplished. Let A B C D represent the earth, A C being the
equator. A spectator at the pole B, would see the pole star directly
overhead, but a spectator at A, on the equator, would see the pole
star in the horizon. Hence, in travelling from the north pole to
the equator, the elevation of the pole star changes from directly
overhead, or in the zenith as it is called, to the horizon, or 90°,
changing its altitude 1° for every degree traveled over the earth's
surface, either north or south. - The astronomer is furnished with
the means of measuring the altitude of the pole star, or its
distance above the horizon by means of the quadrant, or the
astronomical circle which we shall describe, together with some
other astronomical instruments in the next chapter. We have

34 THE WORXD.

now learned three important facts in regard to our earth, and the
celestial bodies, viz: The ceaseless and uniform motion, the
rotundity of the earth, and the actual length Of a degree upon its
surface, and this is no small progress, supposing we commenced
entirely unacquainted with the subject. Fortunately, as we pro-
ceed to show the gradual improvement in astronomical knowledge,
we can also give a history of the science, and briefly notice those
eminent men, and their discoveries, whose labors have brought
astronomical science to its present state of perfection. Supposing*
that we are ignorant of the nature of the motion perceived in the
heavenly bodies, we will lay aside further observation for the
present, and notice some of the instruments employed in astrono-
mical discoveries.

ASTRONOMICAL THEORIES. 25

.
'

* ,:**ME**W; i

CHAPTER II.
MIMC

Astronomical Theories.

" He sat and read. A book with silver clasps,
All gorgeous with illuminated lines
Of gold and crimson, lay upon a frame
Before him. ' Twas a volume of old time ;
And in it were fine mysteries of the stars,
Solved with a cunning wisdom." — Willis.

THE imperfect historical records of the nations of antiquity
prevent us from determining with certainty when, and with whom,
astronomical science had its origin. It is certain however, that it
was cultivated at a very early age by the Egyptians, the Chal-
deans, the Bramins of India, and the Chinese. In a fine
climate, and fertile country, inhabited by nomadic tribes, we can
well imagine the sublime spectacle of the heavens to have arrested
early attention. At a later period, when the motion of the sun
among the stars began to be noticed, and consequently the helical
rising and setting of certain stars, i. e., their rising or setting just
before or after the sun, became the signs of approach of certain
seasons, the stars were grouped into constellations, and fanciful
names given to them. Thus we find Hesiod alludes to the helical
rising of Arcturus, and Thales mentions the number of days
after the vernal equinox, when the Pleiades set just as the sun
arose, by means of which we are now enabled to tell the age in
which he lived, as will be explained hereafter.

The constellations being located and named, and the sun's
apparent path determined in the heavens, astronomers began to
observe more carefully the motions of the sun, moon, and planets,
among the stars, and endeavored to frame a system of the world
which would explain all the apparently irregular motions. It was

26 THE WORLD.

very early observed that the sun and moon moved around the
earth with different velocities from the stars1, and that there were
certain bodies, five in number, which also appeared to be wan-
dering in the heavens, these were called planets, from a Latin
word meaning to wander, and were named in order, according to
their supposed distance from the earth, Mercury, Venus, Mars,
Jupiter, and Saturn. As soon as these wandering bodies were
closely observed, certain irregularities in their motion attracted
attention, instead of moving uniformly in a circle in the heavens,
like the sun, their paths were often broken, and even turned back,
as represented by the lines below, moving from a to b direct, i. c.,

in the order of the signs, from b to c, retrograde, or contrary to
their previous motion, at b and c, apparently still, or stationaiy for a
short time, and from c to d moving again direct. In addition to
these irregular movements, two of them were observed to always
remain in the neighborhood of the sun, viz. Mercury and Venus,
while Mars, Jupiter, and Saturn were often seen directly opposite,
rising when the sun was setting. Hence, in framing any theory,
it was necessary to account for these motions.

All the early astronomers supposed that the earth was the centre
of the system, and that all the celestial bodies were revolving
around it. The only system of the world which attracted much
notice, was that of Ptolemy the great Egyptian king and philoso-
pher, called, from him, the Ptolemaic system. This is the
system which we would naturally adopt upon casual thought.
Here is the earth occupying the centre, and around it the moon is
supposed to be revolving not quite as fast as the sun, next comes
Mercury, then Venus, the Sun, Mars, Jupiter, and Saturn, beyond
the whole was supposed to be the grand prinwm mobile, a sphere-

PTOLEMAIC SYSTEM. 27

to the surface of which the stars were all attached, and revolving

once around the heavens in 24 hours. To account for the irregu-
lar motions of the planets before noticed, a modification of this

system was necessary. Thus B A C maj^ represent the orbit of

28 THE WORLD.

Mercury around the earth, the planet however, instead of revolving
in this circle, was supposed to be revolving in another smaller
circle c a b d, whose centre v was carried forward as the circle A
B C revolved around the earth, in the order of the letters, the
planet moving in the contrary direction in the small circle c a b d
would apparently describe the curve line d e f g h, being sta-
tionary at / and h, and apparently moving backward through the
arch f g h. Now in order to make Venus and Mercury always
accompany the sun, the centre v of the small circle, was supposed
to be always in a right line nearly, between the earth and sun.
Such was the Ptolemaic system, and as it appeared to explain the
irregular motions by really uniform, or true circular motions, it was
soon adopted as the true system of the world. In the time of
Ptolemy astronomical instruments began to be used; for some
time previous however, the eastern nations, in order to ascertain
the instant of mid-summer, or mid-winter, had been in the habit
of measuring the length of the shadow of a vertical gnomon or
style, but Ptolemy introduced the use of graduated spheres. We
have already observed that all circles are divided into 360 degrees,
and these subdivided into 60 minutes each. Hence it is evident
that by means of a graduated circle, angular distances may be
measured in the sky. An angle, it must be remembered, is simply
the inclination of two lines and has no reference at all to the
length of the lines, thus S A B is the angular distance of the star

S from the object B. To observe this angle, or inclination, we
may use a small graduated circle thus. Lot A C D be a circle
graduated into 360°, having a moveable index turning on its,
centre, which index is furnished at each end with a sight-hole.
First look with the index towards the object B, and observe the

MEASUREMENT OF ANGLES. 29

point where the index. marks the circle, say at 10°, then turning

-----R

the index towards S, observe where it makes the circle, say 20°,
the difference 10°, is the angular distance of S from B. The
instruments of Ptolemy were constructed upon this principle
though not so perfect, using shadows, and other contrivances,
instead of simply observing through two vanes or sight holes.

Ptolemy had not intended his system to be received other than
an hypothesis', which might account for the observed motions ; he
did not profess this to be the actual order of the world, but his
successors, without their great master's love for truth and careful
study, soon gave to these supposed spheres and orbs, a real exis-
tence, and the heavens became crowded with crystalline spheres
moring in all directions, and with all velocities, and as often as
new motions, or irregularities in the old ones were detected, new
circles moving at their centres round the old ones, were added,
called epicycles, so that at last cycles and epicycles, revolved in all
directions, bearing the planets along with them, until amid the
crowd of spheres and crystal orbs the brain grew dizzy, and could
not comprehend the mysterious revolutions. Amidst all this
confusion of " Cycle and epicycle, orb on orb," a bright
luminary arose, arid with a master iiand dashed aside the
crystal spheres of the successors of Ptolemy, substituting instead,
the simplicity of truth. This man was Nicholas Coperni-
cus. At the time when the true svstem was about'to be made

30 THE WORLD.

known, the followers of the Egyptian school were in their glory,
Purbach, professor of Astronomy at Vienna, had reviewed the whole
system, and by the addition of various new spheres, had succeeded
in explaining all the observed irregularities of the planets, and
thus silenced forever the sneers of infidels, and particularly those
of Alphonso X. King of Castile, who had observed, "Had the
Deity consulted me at the creation of the universe, I could have
given him some good advice." But the hour of triumph
was short. Error, which had sat like a cloud npon the mountain
top, overshadowing all below, was ready to vanish before the bright
beams of the sun of Truth.

The obscurity which hangs over those early days, conceals the
steps by which Copernicus arrived at the knowledge of the true
system. It required indeed a bold mind to disregard all the
religious dogmas of the time, and methodise a system, which ns
Tycho Brahe, himself an illustrious astronomer, observes,
"Moved the earth from its foundation, stopped the revolution of
the firmament, made the sun stand still, and subverted the whole
ancient order of the universe." Such a mind however, Coper-
nicus seems to have possessed, although his modesty prevented
him from publishing his views, until at so late a period, that he
only lived just long enough to see a printed copy of that book
which was to gain him immortal honor. At this time, in the
words of his admirable friend the Bishop of Culm, "He was
occupied with weightier cares" — about to test the reality of that
unknown world whose mysteries sages have endeavored but in
vain to understand, from remotest ages. The first gleam of truth
which burst upon the mind of Copernicus was doubtless the idea
that the apparent revolution of the starry orbs around the earth
from east to west once in 24 hours, was actually accomplished by
a revolution of our earth on its axis in the same time but in the
contrary direction. Refer to the following diagram and observe
the simplicity of this explanation.

Here is the earth, anH around it on all sides the celestial con-
cave. Suppose now an observer situated upon the earth should
see a particular star A, directly overhead at sunset, and that the
earth was revolving once on its axis in 24 hours in the direction of

DIURNAL REVOLUTION OF THE EARTH. 31

the letters A B, after an interval of 6 hours, the spectator would

jr

,

*

,.

********

arrive under B, and perceive the star B directly overhead while the
star A would be just ready to sink below the horizon. After an
interval of 18 hours more he would again arrive under A, having
performed a complete revolution. Now as all the stars are
observed to have a perfectly uniform motion, moving once around
the earth in 24 hours, never changing their apparent positions
with regard to each other, doubtless this supposition appeared to
Copernicus the most rational, and its truth is now incontestably
proved, and universally admitted. The great motion of the
heavens being thus shown not to be real, but only apparent,
Copernicus naturally endeavored to ascertain how far certain other
motions, which the followers of Ptolemy explained by innumera-
ble cycles, and crystalline spheres, as if all their observed motions
were real, might be explained by a movement of our earth
instead of these bodies. The actual size of the sun and planets,
as also their actual distance from the earth, not being known at
that time, rendered this problem more difficult, and beside this,
he was wholly unacquainted with the laws of gravitation. Hence
it was no ordinary effort of mind to reduce the various compli-
cated motions of the planets and the sun to one harmonious
system. Pythagoras, the celebrated Greek philosopher who lived
500 years before Copernicus, had already suggested the idea that
the sun was the central body, and that the earth and planets were
revolving about the sun at various distances. He did not attempt

32 THE WORLD.

however to account for the irregularities observed in the planetary
motions. Copernicus might have easily perceived, and no doubt
did perceive, that the motion of the sun backwards in the heavens,
and to which we have alluded, was only apparent, and was due to
a real motion of our earth, which may be illustrated thus :

Let S represent the sun, occupying the centre of the system,
and E the earth moving in an orbit around it. Now an observer
on the earth at E would perceive tbe sun S, apparently projected
against the heavens near the star B. If the earth was stationary,
then after 24 hours, turning around in the direction of the arrow,
i. e., frem Jeft to right, or west to east, (the north pole in the dia-
gram being supposed towards the eye) the sun would again appear
close to the star B, and the sun and stars would come to the
meridian or mid-heaven together. Now suppose the earth to have
moved forward in its orbit to A, and imagine the sphere of stars
figured in the diagram to be expanded to an infinite distance, it
will be easy to see that the sun and the star B, will no longer
come to the meridian together, the meridian being represented by
the black line on A, but that, on the supposition that the earth is
turning in the direction of the arrow, the sun would come to the
meridian, or this line, much later than the star, and would appear
among the stars at C. To explain tbe motions of Mercury, and

COPERNICAN SYSTEM.

33

Venus, Copernicus supposed them to be revolving around the sun,
but in orbits within the earth's. This would explain why they
were never seen at any considerable distance from that luminary
and also the various irregularities observed in their motions,
Thus :

Let S be the sun, E the earth, and V, Venus. In the situation
represented in the diagram Venus would appear among the stars
at A, the sun being at B. In this case, supposing the earth to
turn on its axis in the direction of the arrow, the sun would come
to the meridian or overhead, to an observer on its'surface, before
the planet, which consequently, setting after the sun, would be the
evening star. Now supposing the earth stationary in its orbit, let
Venus move from V to W. This would cause her to describe
the arc A C in the heavens, gradually approaching the sun, which
is apparently at B, and then appearing 011 the opposite side.
When in the position W, still supposing the earth to turn on its
axis in the direction of the arrow, Venus would come to the
meridian, or rise before the sun and consequently be morning
star During the rest of her revolution in her orbit, from W to V
she would seem to move backwards in the heavens, or retrograde
from C to A, and at the points C and A she would appear for a
short time stationary. We have supposed the earth to be at rest,

34 THE WORLD,

but it really moves in its orbit in tho same direction as Venus,
though much slower, -and the phenomena are the same in kind as
though the earth was still. The phenomena of Mercury may
be explained in the same manner as those of Venus, but as
Mercury is never seen at so great a distance from the sun as
Venus, its orbit is placed between the orbit of Venus and the sun.
The planets Mars, Jupiter, and Saturn being occasionally observed
at midnight, or directly opposite to the sun, their orbits are
located exterior to that of the earth, and in the order just named,
which is according to their relative velocities.

Such is the simple and beautiful system of the world known as
the Copernican system. Long as time will last, the memory of
its successful author shall live. His fame as everlasting as the
duration of those bright orbs which roll around the sun. Coper-
nicus lived in an age far behind himself, and no .doubt refrained
fromf publishing his views to the world from fear of ecclesiastical
censure, although indeed he ridicules this idea, and dedicates his
book to Pope Paul III, and was induced to publish it by the persua-
sions of Schuenberg, Cardinal of Capua and Gisas, Bishop of
Culm.

In those days the Bible was not only received as the rule
of faith, but as the oracle of nature. To assert the rotation
of the earth on its axis, and deny the revolution of the sun around
it, was impiety, and direct contradiction to scripture. Joshua
commanded the sun to stand still, and therefore the sun must
move. So it is said, "The pillars of the earth are the Lord's."
And yet no one supposed at that time that the earth was liter-
ally sustained on pillars. Sir Isaac Newton himself, would
say " The sun rises," " The sun sets," and yet would mean far
from asserting that the sun actually moved. The ignorance
which repressed the efforts of Copernicus, at a later day crushed
the energies of Gallileo, who with his heaven-directed tube main-
tained and demonstrated the truth of the Copernican system.

Referring to the next diagram, it will be seen that upon the
supposition that Venus is revolving between the sun and the earth,
her disk would assume the phase of our moon. For example
when at A he would appear wholly illuminated, her enlightened

I'HASKb Ol- VKMJs. 35

disc being turned towards the earth at E. When at B, she would
appear half illuminated, as the enlightened hemisphere is now
partly turned from the earth. At C, she would appear either wholly
unilluminated or at best a 'slight crescent, since her enlightened
portion is now wholly or almost wholly turned from the earth, at
D, she would appear again half illuminated. These phases were

not really observed in the case of Venus, although Copernicus
predicted they would be, when we could see Venus plainer, and this
was considered by some as an unanswerable argument against the
truth of his theory, while others maintained that the planets shone
by their own inherent light, and of course had no phases. Such
was the state of science when Copernicus died, but already the
dawn of a brighter clay was advancing. The use of spectacle
glasses was quite common, and many shops were engaged in
their manufacture. It is related that some children of a Dutch
optician, while playing with the spectacle -glasses one day, chanced
to arrange two at such a distance as gave a magnified but inverted
image of distant objects, and the optician following out the idea
thus accidentally presented, the telescope was first made in Hol-
land. Gallileo, at this time professor of Mathematics, at Padua,
heard of this wonderful tube, and immediately set himself to
work to construct one. In this he was eminently successful, and
in his hands it gave the death blow to the opposers of the system
of Copernicus. With the telescope, Venus was clearly ob-
served exhibiting the phases which Copernicus had predicted.

36 THE WORLD,

We cannot imagine the delight which must have thrilled the
heart of Gallileo when he, for the first time since the creation of
man, beheld the phases of the evening star. Already a cham-
pion for the true system, he must have hailed- this complete and
unanswerable evidence, with a joy such as we cannot now
conceive. We would have supposed that now the absurd dogma
which asserted that the earth was the grand centre of the universe,
and denied its diurnal revolution, would have been forever rejected,
but alas! error is difficult to eradicate,Mt takes root easily, and
attains a most luxuriant growth, without any cultivation.

Henceforth Gallileo's life was embittered by a persecution from
the Church. The doctrines which he maintained, and so ably
advocated, were supposed to contradict the Bible, and at the old
age of 70, after a life spent in the cause of science, he was tha
subject of a most humiliating spectacle. A hoary headed man,
with trembling voice abjuring what he knew to be the truth,
abjuring, cursing, and detesting as heresies those doctrines which
he had spent the vigor of his manhood in establis hing, those
eternal and immutable truths which the Almighty had permitted
him to be the first to establish, and with his hand on the Gospels,
avowing his belief that the earth was the centre of the system,
and without the diurnal motion on its axis. Oh ! that the strong
spirit which sustained the early martyrs for religion, had supported
this martyr of science. — But the feebleness of age was upon him,
harrassed and tormented, worn out by long persecution, his spirit
yielded, and never recovered from the degradation ; blind and
infirm, he never talked or wrote more on the subject of astronomy.
Here are the qualifications of these two propositions which asserted
the stability of the sun and the motion of the earth, as qualified by
the Theological Qualifiers :

I. The propostion that the sun is in the centre of the world,
and immovable from its place, is absurd, philosophically false, and
heritical, because it is expressly contrary to the Holy Scriptures.

II. The proposition that the earth is not the centre of the
world, nor immovable, but that it moves, and also with a diurna
motion, is also abimrd, philosophically false, and theologically
considered equally erroneous in faith."

RELIGION AND PHILOSOPHY. 37

It hardly seems credible that such opposition could have been
seriously entertained by grave and learned dignitaries, when the
proofs were so abundant to the contrary. Yet at a later day, we
find the Jesuit Fathers, P. P. Le Seur.and Jacques declaring
in the preface of their edition of Newton's Principia :

" Newton in this third book, has assumed the hypothesis of the
earth's motion. The author's propositions are not to he explained
but by making the same hypothesis also. Hence we are obliged to
proceed under a feigned character ; but in other respects, we
profess ourselves obsequious to the decrees of the Popes made
against the motion of the earth."

Such was the strong hold which ignorance had upon the minds
of men, that like Sizzi, who refused to look through Galileo's
telescope for fear he might be obliged to acknowledge the actual
existence of Jupiter's satellites, they would not receive the truth
when it was absolutely forced upon them. Even in the present
enlightened state of the world, there are many who object to the
science of Geology, because some of its teachings, they imagine,
are contrary to the word of God.

• Religion and Philosophy can never conflict, if hoth are based
upon the Truth. We may be well assured, that the rapid ad-
vancement of science and art, will, so far from being injurious
to the cause of Religion, tend but to illustrate, and exhibit, in clear-
er characters, the wisdom and goodness of the Creator. Nothing
can be more unwise, or of greater injury to the cause of Religion,
than the foolish opposition which is sometimes made to the recent
developments, if they may be so termed, of natural science.
Religion points us to another sphere of action ; it opens before
us another world; and bids us aim for higher and nobler ends than
we strive for here. The questions, whether the Heavens are
eternal, or our own earth a million, or six thousand years old, are
of little moment compared with the question of the immortality
of the soul. Science elucidates the former, Religion the latter.
Since, then, their aim is so very different, and since we believe
both to be based upon Truth, and therefore immutable, why
perplex ourselves with questions which can never be answered ?

38 THE WOULD,

To the Geologist, the proof is abundant, that the present globe
has had a being, and been inhabited by wonderful animals and
plants, myriads of years past. To the Astronomer, the proof is
equally conclusive, that the Heavens are infinite, and eternal, that
our system will, at least so far as natural causes are operating,
continue for ever, unchanged, and unchangeable. To the
Christian, the proof is equally strong, perhaps stronger, that the
word of revelation is what it professes, the message of God,
teaching what Science could never learn us, but not conflicting
with it.

PARALLAX.

CHAPTER III.

Parallax.

" The broad circumference

Hung on his shoulders like the moon, whose orb
Through optic glass the Tuscan artist views,
At evening, from the top of Fesole'
Or in Valdarno, to descry new lands,
Rivers or mountains, in her spotty globe." — Milton.

WE have now shown that our earth is revolving around the
sun, which is the grand central luminary, and that within- its
orbit are the orbits of Venus and Mercury, while exterior are the
orbits of Mars, Jupiter, and Saturn. We have learned to look
upon these bodies as orbs, or balls like our own earth, and suppose
them to revolve like our earth upon an axis. We now desire to
know something of their distance from us, and the actual velocity
with which both we and they are moving. The diameter of our
earth we have assumed at 8000 miles, or equal lengths, we can,
from knowing this, ascertain the distance of the moon from the
earth, and of the earth from the sun. Every one is familiar
with the fact, that every change of position of a spectator,
causes an apparent change of place in the object viewed. Thus,
if while in a certain position, we observe a particular house to be in
the range, or same line with a distant tree, then upon changing
our position, the house will no longer be in a* line with the tree,
but will appear to have moved in the contrary direction. This
apparent change of place of the object, due to a real change of
place in the observer, is called parallax, and by its means, we can
determine the distances of the heavenly bodies. Thus, supposing
spectators on opposite portions of the earth's surface, as at A and
B, to view the moon or a planet, at c, the observer at A, will see
the object c, apparently at a, while the observer at B will per-
ceive it at the same time at b. Here is an apparent change of

* -

40

THE WORLD.

place, viz : from a to b, due to a real change in the position of

the spectator. This change, enables us to ascertain the dis-
tance of the object with much precision, for supposing A and
B joined by a line, we have a triangle ABC, in which one side A
B, is known, and all three angles — for the observers at A and B
determine with some graduated instruments, the inclinations of
the lines A c and B c to the line A B. We can illustrate the
method by which the distance of an object is ascertained by means
of graduated instruments thus :

Suppose a'spectator at B, to observe by means of a graduated

MEASUREMENT OF DISTANCES. 41

circle, the number of degrees subtended by a distant object,
as a church, at A C, and let this angle be two degrees ; we have
here a triangle A- B C, and knowing its angles, and any one
side, we can determine the other sides. Suppose we know
the side B C, or the distance of the Church, to be 1 mile, we
can ascertain the height A C thus : Twice B C, or 2 miles,
will be the diameter of a circle whose centre is the eye of the
spectator, and whose radius, the distance of the Church. Three
times this (nearly), or 6 miles, will be the whole circumference,
and six miles divided by 360 will give the length of one degree,
and twice this, since the angle A B C is 2 degrees, will give
the height A C. Allowing 5000 feet to the mile, 6 miles would
be 30,000 feet, and this divided*by 360, gives 83J feet for the length
of one degree, consequently 2 degrees are 166§ feet, which is the
height required. Now in any triangle whatever, we can deter-
mine the length of all its sides, provided the length of 'one side is
given and also the angles. We do not mean to be understood
that this is the actual process employed by astronomers to deter-
mine the distance of the moon, and other heavenly bodies, but
simply introduce it as an explanation of the principle.

By means of parallax, the distance from the moon to the earth
has been ascertained to be 60 semi-diameters of the latter, and the
distance of the earth from the sun has been determined
to be 95,000,000 of miles. When we reflect upon this
vast distance, the absurdity of that system which denied to
the earth a revolution on its axis, once in 24 hours, is striking-
ly apparent. We could not conceive of the amazing velocity
with which the sun must move, at the immense distance
which it is situated from the earth, if it was obliged to
travel once around in 24 hours. It would require a rate of about
24,000,000 miles per hour, or 400,000 miles in one minute,
and 6,666 miles each tick of the clock. Such velocity is abso-
lutely incredible, and this would be to save our little globe from
turning on its axis at the rate of 1000 miles an hour, or about 17
miles in one minute. — When the distance of any of the heavenly
bddies becomes known, its actual diameter in miles-can be easily
ascertained. It is no more difficult to obtain the diameter of the

42 THE WORLD.

moon, when her distance from the earth is known, than to deter-
mine the height of a church steeple when we know' how far it
is from the observer. We here represent the moon and. a part of

B]

its orbit, the earth being supposed to be at A. The distance A B
or A C, is 240,000 miles, and the angle B A C, which is observed
with a graduated circle, is about 30 minutes, or half a degree.
Proceeding as in the case of the Church, twice A C is
480,000 miles, and three times this is 1,444,000 miles which is the
circumference of a circle whose centre is the centre of the earth,
and whose radius, or half diameter, is the distance of the moon.
This circumference divided by 360, gives 4000 miles for the length
of one degree, and half this is 2000 miles the length of half a
degree, which is the diameter of the moon. The actual diameter
of the moon is 2140 miles, for the angle B A C is nearly 31
minutes, or a little over half a degree.

In precisely the same manner the diameter of the sun is
ascertained to be 880,000 miles. Hence we learn, that if a spec-
tator at the sun, should look towards the earth, it would appear
only the one hundredth the diameter which the sun appears to us,
or not larger than a very small star. How absurd then is the idea
that the sun revolves around the earth. — We now have a just
conception of Ihc solar system, and have learned to look upon the
sun as the central body, around which the planets revolve in order,
our earth being one of the smallest. Far beyond it, other magnifi-
cent orbs are moving silently in the depths of space, peopled with
myriads of intelligent beings. Very far beyond the boundary of
our own system, we believe there are others more beautiful, and

IMMENSITY OF CREATION. 43

t hat every star which adorns the heavens, and upon which we turn
such unheeding eyes, is a sun, giving light, and warmth, and hap-
piness to ,its own attendant planets. Nay, more than this, we
believe that all those countless myriads of stars which the tele-
scope reveals, twinkling from distances so far, that if blotted
from existence, their light would continue a thousand years, so
long it would take to travel thence to us, are all centres of sys-
tems, around which, worlds peopled with intelligences of the
highest order, are revolving, and yet, we have obtained but a faint
idea of the immensity of Creation. Where is the central throne
from which all power emanates ? The throne of the Eternal.
Imagination fails. Reason shrinks back abashed, but Faith, with
more than telescopic eye, pierces to that centre, and sometimes
catches a gleam, a faint ray of the brightness of its glory. What
wonder that astronomy should be called the noblest science,
since it affords scope for the highest order of intellect, and pre -
sents truths unequalled for their grandeur and sublimity. Uncon-
sciously we are moving on, life and death is every where around
us, but the heavens seem unchangeable, the type of eternity.
We an unwilling to believe that the principle within us, whatever
it may be called, soul, spirit, or reason, which is thus capable of
comprehending sublime truths, perishes, and becomes inanimate,
like the dead flowers, and withered leaves. We feel an ardent
aspiration after higher and purer knowledge, and cannot doubt
that such longings will one day be gratified.

These maybe called " flights of the imagination," but we would
do well to remember, that there are things, which are as far beyond
the imagination to conceive, and which are more strange than
this, yet of whose reality we cannot doubt. Such is the progres-
sion of light,, and of electricity. The eye cannot follow them, nor
the imagination, as they rush on, with a speed of 200,000 miles
in one second ! And, quicker than this is the transmission of
that mysterious influence, called gravitation, which acts with all-
controlling force, through distances, utterly inconceivable to the
human mind, causing the immense masses of the planetary orbs
to rise and fall like bubbles on the ocean wave. Shall we then
call all these flights of the imagination, or mere fancy, and with

44

THE WORLD.

those doubting men of old, deny the reality of everything, ever*
our own existence ?

We give above a representation of the earth, as it would prWtmbly
appear to a spectator removed to the distance of the moon. The
same hemisphere of the moon is always turned towards the earth,
this is caused by a revolution on its axis in the §ame time that it
revolves around the earth. Consequently, a spectator on the
moon, would always behold the earth as a stationary body in the
heavens, as we should behold the sun, if the earth turned on its
axis but once in 365 days. The apparent size, of the earth, seen
from the moon, would be a globe of about four times the diameter
of the moon. In the imaginary view we have given, the great
Indian Ocean is directly in front, the Pacific at the rig-lit, and
the Atlantic, at the left. The large inland seas are shown; also,
Europe, Africa, Asia, and New Holland ; and around its north
pole are fields of ice, and cloudy patches are over the whole sur.
face. Such a vast globe, suspended apparently in the heavens, and.
revolving on its axis with a motion easily perceptible, must be a
magnificent spectacle, and if the moon is really inhabited, well
worth a journey round half its surface to behold.

TIMK. 45

CHAPTER IV.
Time.

" The last white grain

Fell through, and with the tremulous hand of age
The old astrologer reversed the glass ;
And, as the voiceless monitor wenf on,
Wasting and wasting with the precious hour,
He looked upon it with a moving lip,
And, starting, turned his gaze upon the heavens,
Cursing the clouds impatiently." — Willis.

WE have now determined the relative situation of our earth
with regard to the heavenly bodies, and its size compared with
them, and we are prepared to investigate the causes of some of
the changes which we witness upon its surface. Previous to this,
we will devote a few chapters to Time and the Calendar, for the
familiar expression of a day, or an hour, or a year, seldom conveys
to the mind the exact meaning which belongs to those terms.
We may consider time to be a definite portion, that is, a portion
which can be measured, of indefinite duration, or, as Young
poetically expresses it :

" From old Eternity's mysterious orb,
Was Time cut off, and cast beneath the skies."

Time was personified by the Ancients, under the figure of an
old man with scythe and hour-glass, and a single tuft of hair on
the forehead. The scythe was emblematic of that all-powerful
influence which cuts down every thing as it sweeps past. Man,
and his works, perish, and crumble before it, as the grain falls
before the mower's scythe. Nor is the emblem unappropriate.
The keen edge, while it sweeps through the field of ripe grain,
suddenly laying low the proud stalk, cuts down many a flower,
and tender stem. The hour-glass, held in the outstretched
hand, portrayed the passing moment, and the sand, in its cease :
less flow, marked the ebbing of the current of life. We cannot

40 THE WORLD.

refrain from quoting a beautiful little poem, from " Hone's Every
Day Book," entitled

INSCRIPTION,

FOR MY DAUGHTERS' HOUR-GLASS.

Mark the golden grains that pass,
Brightly thro' this channell'd gkss,
Measuring by their ceaseless fall,
Heaven's most precious gift to all !
Busy, till its sands be done,
See the shining current run ;
But, th' allotted numbers shed,
Another hour of life hath fled !
Its task perform'd, its travail past,
Like mortal man, it rests at last ! —
Yet let some hand invert its frame,
And all its powers return the same,
Whilst any golden grains remain,
'Twill work its little hour again, —
But who shall turn the glass for man,
When all his golden grains have ran ?
Who shall collect his scattered sand,
Dispersed by Time's unsparing hand ?
Never can one grain be found,
Howe'er we anxious search around!

Then, daughters since this truth is plain,
That Time once gone, ne'er comes again, —
Improv'd bid every moment pass —
See how the sand rolls down your glass !"

The forelock was also emblematical, indicating that if we
would improve the time, we must take it by the forelock, and that
time once passed left no hold by which it could be reclaimed.
Such was the beautiful emblem of time devised by the ancients,
and which we still retain.

The diurnal revolution of the earth, or rather, as it was once
believed, the revolution of the heavens around the earth, was
observed at a very early day to be performed with the utmost
regularity. The return of night, and approach of day, the
duration of the night and day, are the first great natural pheno-
mena which engage attention, and we may suppose, therefore,
that the apparent revolution of the stars around the earth was at
a very early period, employed to determine equal intervals of
time. Sun-dials were undoubtedly the earliest means employed

DIALS AND CLEPSYDRX. 47

to mark the passage of time, and are in common use even at the
present day. Every country tavern is furnished with its meridian
or noon-line, which oftentimes is nothing more than a scratch
ov mark in the floor, and the gnomon, or shadow-stick, is the side
of, a window or door. In our younger days, we have watched
with far more interest, the shadow approach the humble line
drawn on the floor of a tinker's shop, than in more mature years
the steady passage of a star over the wires of a transit telescope.
And we have not forgotten those days of sun-dial memory, when
we were, unconsciously, children playing with time. We find
allusions to the dial in the Old Testament. The dial of Ahaz,
which was, undoubtedly, a large public edifice. Such was the
dial constructed by Dionysius, and such the dial used by the
Chinese, and in India. Sun-dials were liable to many objections ;
they could only be used when the sun was shining, and conse-
quently at night, or in cloudy weather they were worthless. The
Clepsydra, or water-clock, was therefore invented at an early date.
It i» said that they were found among the ancient Britons, at the
time of the invasion by Julius Caesar.

The first water-clocks were made of long cylindrical vessels,
with a small perforation at the bottom. These being filled with
water, marked the passage of time by the descent of the fluid
column. Various ornamental contrivances were subsequently
introduced, but they were all dependent upon the same principle.

We will imagine one of the early philosophers, with his water-
clock, starting the stream when some well known star was
occulted, or hidden by a distant object, the tube being long enough
to continue the stream until the next night. As the heavens
move on, we find him watching the descent of the liquid, and at
the approach of the succeeding evening, when the same star is
again occulted by the same object, he marks the level of the liquid
in his tube, and selecting another star, for the first has gone out
of sight, he fills the tube, and at the given signal, when the star
passes behind the hill, or other occulting object, he permits the
water to flow. On the succeeding evening, as this star is again
hidden, he observes the fluid, and finds it at precisely the same
level as before, and thus arrives at the conclusion that the star*

48 THE WORLD-

all revolve around the earth in the same time, or, more philo-
sophically speaking, he learns that the earth turns uniform!}'' on
its axis — performing each revolution in exactly the same interval
of time. The space thus obtained "on the clepsydra, for a revo-
lution of the heavens, we may imagine him dividing into
portions that will mark the subdivisions of the day. These
divisions would not all be equal, but decrease in length as
the height of the fluid column decreased. His instrument, thus
adjusted to measure the flight of time, we may suppose him to
observe the exact instant of sunset, and after an interval of a
day, again making the same observation. He would find upon
careful observation that this interval was longer than the interval
required for a star to revolve around the earth, by about 4 minutes,
if his instrument would detect so small a quantity. In other words,
he would find that the sun was apparently moving backward in
the heavens. And now, he is, perhaps, for a moment puzzled
which measure of time to adopt, that of the stars, or of the sun.
Convenience points out the latter, and consequently astronomers
regulate their time measurers to divide the solar dayinio 24 hours ;
the other is called the sidcrial day, and is about four minutes
shorter.

For a long time, even after Copernitus and Galileo had estab-
lished the fact of a rotation of the earth on its axis, there were no
means of measuring intervals of time more correctly than by the
water-clock. It is true, that instruments made of wheels, and
moved by weights, were, in Galileo's time, in use, but as they
were without any regulators, the time was too inaccurately mea-
sured to be of any service. The discoveries which were being
made by Tycho Brahe, and Kepler, demanded some more
accurate method of registering the time. It is related that
Galileo, observing the swinging of a suspended lamp, in a
Church at Pisa, and noticing that the vibrations, whether long or
short, were performed in equal times, conceived the idea of
adapting such a contrivance, now called a pendulum, to measure
intervals of time. His apparatus was rude enough, and it was
necessary to employ a boy to occasionally give the pendulum a
slight push when it was near resting. It does not appear, at first

StPERIAL DAt. 49

thought, that long and short vibrations will be performed in the
sam? time — yet this is true, at least when the pendulum is quite
lonf, anU the arcs over which it swings are of moderate lengths.
Huygens conceived the idea of applying the pendulum to the
clock, as a regulator, and succeeded in accomplishing this, and
thus gave to the world an accurate measurer of time. The clock
thus perfected, became so accurate, that it was necessary to contrive
some more accurate means to regulate it. Hitherto, the successive
occultations of some star, observed without the aid of a telescope,
had been sufficient, and the time of noon, or 12 o'clock, was
obtained by sun-dials, and other means, with sufficient accuracy,
for the instruments hitherto employed.

Any occurrence, which takes place at regular intervals, may be
adopted as a regulator of time, but the revolution of the earth on
its axis is by far the most accurate. For certain reasons, which
will be given presently, the sun is apparently subject to such
irregularities, that the solar days, or exact interval, from the' time
the sun is on the meridian, until his return to it again at the
successive revolution, are of unequal lengths. In other words, the
solar day is variable. Now the real revolution of the earth on its
axis, is the time in which any given meridian, or situation on the
earth, moves from a particular star, back to that star again. Thus :
A.

Let A, B, O, D, be the earth, its north pole N, being towards
us, and suppose it revolving in the order of the letters. Let N D
be the meridian, or north and south line passing through some
particular spot, Greenwich, for example, shown at E, and let the
star S, be upon the meridian, that is, if this line was extended to
the heavens, or, more properly, a plane passing through this

50

THE WORLD.

line, suppose the star to be upon it. As the earth turns on its axis,
the star is left behind, and after a complete revolution, the meridian
again arrives to it, this interval is called asiderial day, or day as
determined by the stars, and to ascertain this day, or its length,
we must have some means of determining with the utmost
exactness when the star is on the meridian. This is accom-
plished by means of the transit instrument, invented by Huygena,
and shown in the engraving below.

The ordinary transit instrument consists of a telescope, A B, of
any convenient length, fixed firmly at right, angles to a conical
hollow axis, E F, the exti'emities of this axis are truly turned,
and rest in two angular bearings which are called Y's, since they
are not unlike this letter, the instrument can be lifted out of these
bearings, and reversed, so that the ends E and F may change
places. The end of the axis F, is furnished with a small graduated
circle C, for the purpose of reading the elevation, or altitude of
the body observed, and at D, is a small lamp, the light of which
shining into the hollow arm E, is reflected by a reflector inside
the tube, down to the eye. The object of this illumination is
to make a system of fine lines, usually raw silk, or spiders-web,
visible at night, at the same time with the star. In looking into
the transit telescope, five of these lines are usually seen, shown in
the engraving. A B is, by means wo cannot now describe, located

TRANSIT INSTRUMENT.

as exactly in the meridian as possible. It will be seen that when
the axis of the transit telescope, E F, is placed due east and west,
and also made perfectly horizontal by means of the spirit level H,
the telescope A. B, will move in the meridian, i. e.t it will, if

B

directed tq the heavens, mark the exact situation of the meridian,
at the time, of the particular plact where the instrument is
located. We are thus furnished with the means of determining,
with the greatest exactness, the precise time of a siderial revolu-
tion of the earth, and as the apparent time of noon, or twelve
o'clock, is precisely the instant when the sun's centre is on the
meridian, we are also enabled to determine, with considerable
precision, the local time, or clock time at the place.

The transit instrument and the astronomical clock, are the two
chief instruments of the observatory, and by their means, the
positions of celestial objects can be ascertained with the utmost
nicety. It would be out of place for us to describe more minutely
these invaluable aids to the astronomer, and we pass to consider
in the next chapter, the "Calendar," or the division of the year
into months, weeks, and days, and at the same time we shall give
an historical sketch of "its gradual progress to the present state of
perfe'ction.

It is a difficult thing to comprehend fully, or even partially, the
relative dimensions, situation, and movement of our globe. We
are so accustomed to look around us and behold the solid founda-
tions of the earth, to see plains and oceans, extending as far as the
eye can reach, and man is so small, when compared with the

52 tHE VVORLO.

immensity of creation around him, that we are wont to look upon
the hills as everlasting ; and the ground whereon we tread, and
in the utmost confidence build houses, and proud works of art, as
unchangeable. We are so accustomed to behold the grand luminary
which gives light and warmth to the world, and cheers myriads
with its bright rays, rising and marking out the length of a day ;
we are so accustomed to plan ahead, and to contrive for years yet
to come, as though there was no possibility of a change ; we
are so accustomed to behold the fair orb of night, as she illumines
a quiet and sleeping earth, and so wont to gaze upon the ever-
twinkling and bright stars, that we long ago have ceased to think
of our earth as a minute orb, smaller by far than many of those
upon which we turn such careless eyes now. We rarely, if ever,
imagine that its present surface was once the bed of avast ocean ;
that its present crust has been caused to heave and swell like a
sheet spread out upon the waves, uplifted by internal fires, until
the strained surface has cracked open, and the flames, and molten
rock found egress. Careless from a thousand causes, we deem
ourselves, like the conceited wrise men of old, as the only impor-
tant beings of the universe, and our habitation, as eternal, and
unchangeable. It is ihe peculiar province of Astronomy and
Geology, to free the mind from such superstitions, and to elevate
and ennoble it by loftier contemplations. The younger Herschel,
has truly remarked, " Geology, in the magnitude and sublimity
of the objects of which it treats, undoubtedly ranks next to
Astronomy in the scale of the sciences."

Wo have, in the present volume, associated the two, as was
necessary in giving such a sketch of the earth as was planned,
and shall strive to interest as well as instruct the reader. — Of
one thing we are most certainly convinced, and that is, there
is not a more interesting subject, to which we may devote our
attention.

THE CALENDAR. 53

CHAPTER V,

The Calendar.

" Change of days

To us is sensible ; and each revolve
Of the recording sun conducts us on
Further in life, and nearer to our goal." — Kirk White.

THE revolution of the earth on its axis, being adopted as the
standard of measure, it was natural that the number of days to
the .year should be a subject of edrly investigation. We have
already alluded to the helical rising of the stars, and it is apparent
that upon ascertaining the distance of the sun from any particular
star, and after a certain interval, determining when his distance
from the same star, is the same as before, the early astronomers
could determine the length of the year, ox time occupied by the
sun in his apparent revolution around the earth. As it was diffi-
cult to observe any stars at the same time with the sun, its place '
in the heavens, or position in the ecliptic, was determined by
measuring its distance from Venus, and then the distance of
Venus from some known star. Or, we may imagine the time
of sunset to be carefully observed, and afterwards the time of
setting of some particular star, then, upon making due allowance
for the time elapsed, the sun's position among the stars could be
ascertained. The rising and setting of certain stars, or constel-
lations, was early adopted as the precursor of the return of certain
seasons of the year. We find continual allusions to this among
the early poets, and even in the Book of Job, we have, " Canst
thou bind the sweet influence of the Pleiades, or loose the bands
of Orion? The Pleiades were also called Vergillae, i. c., daughters
of the spring. The Egyptians watched in like manner the rising
of the dog star, which gave notice of the approaching season of
inundation by the Nile. The length of the year was soon

54 THE WORLD.

ascertained to be about 365 days ; and as the moon, apparently,
made near 12 revolutions around the earth in that time the year
was subdivided into 12 months, which, in reference to the phases
of the moon, were again subdivided into weeks, of seven days
each. — The time occupied by the sun in the departure from any
particular meridian, until its return to that meridian again, is
called a Solar day, and a similar revolution, a star being the
object, is called a Siderial day. We have already shown that
the Solar day was longer than the Siderial day, on account of the
apparent backward motion of the sun among the stars ; but it is
obvious, that the Siderial day, is the true measure of the time of
revolution of the earth on its axis. Now if the earth made an
exact number of revolutions on its axis, during the time in which
it moves from a particular part of the heavens, back to that par-
ticular position again, it is evident we would have an exact
number of siderial days to a year.

It is found, however, that the siderial year does not consist of
an exact number of days, but contains, also, a fractional part of a
day. When a long interval of time elapses between different
observations, so that the earth makes a great number of revolu-
• tions around the sun, the length of the year maybe very correctly
•ascertained. Thus — On the 1st day of April, 1669, at Oh. 3m.
47s., mean solar time, (which we shall explain presently,)
Picard observed the distance of the sun from the star Procyon,
measured on a parallel of latitude, to be 98° 59' 36". In 1745,
which was 76 years after, La Caille observed the sun, to deter-
mine exactly the time when his difference of longitude should be
the same from the star, as in Picard's observation. Now the day
of the month in which La Caille observed, had been reckoned on
from Picard's time, just as if the year had consisted of exactly
365 days, except every leap year, when a day had been added,
for a reason that will appear presently. It was not until April 2d,
at llh. 10m. 45s., mean solar time, that the difference of
longitude was the same as when Picard observed. Now here it
was obvious that the earth had in reality, made just exactly 76
revolutions. The number of days however, was as follows, viz :
58 years, of 365 days each, and 18 leap years, of 366 days each,

LENGTH OF THE YEAR. 55

and Id. lib. 6m. 58s. more, or in all, 27759d. lib. 6m. 58s.,
which being divided by 76, gives 365d. 6h. 8m. 47s. for the length
of the Siderial year. More recent and exact observations give
365d. 6h. 9 m. 11s.

There are various kinds of years. First, the Siderial year, or
the time which it takes the earth to perform exactly one revolution
around the sun. This year it is not expedient to use, for the
seasons being dependant on the position of the earth with regard
to the sun, it is more convenient to have for the length of a
year, the time from the commencement of spring to the com-
mencement of spring again, and this is a period which, for a
reason we will soon explain, is shorter than a siderial year. This
year is called a Tropical or Equinoctial year. Again, inasmuch as
this year does not consist of an exact number of days, and as it
would be excessively inconvenient' to have a year begin at any
other time except the commencement of a day, we have the Civil
year, which consists of exactly 365 days, and every fourth year,
of 366. — We have already given the length of the Siderial year,
which is the time of a true revolution of the earth in its orbit,
but the length of the equinoctial year, or year from beginning
of spring, to spring again, is shorter than this. It is obvious
that the equinoctial year is the one which most intimately con-
cerns us, all agricultural, and other operations, being entirely
dependant upon the seasons.

When we explain, in the next chapter, the cause of the seasons,
we shall show why this year, must be shorter than the Siderial
year. Meantime we may suppose one of the early philosophers
detecting it in this manner. The path of the sun in the heavens
being ascertained, it was soon observed that it was inclined at a
certain angle, with the apparent diurnal paths of the stars. Thus,
if we observe a certain star to-night, (mid-summer,) which rises
due east, and watch its diurnal path, or the line which it traces
in its apparent motion over the heavens, we will find it a part of
a circle, whose centre is the pole of the heavens, near which the
pole star is situated, and the star will set due west : at a certain
point midway between east and west, it will reach its highest
altitude, after which it will begin to set, this highest altitude is

56 THE WORM).

when it is in the meridian, or mid-heaven, and the meridian of a
place, is a plane, or direction, which passes through the spectator,
and the north and south point. If we observe another star which
rises 10° south of east, we will find it arriving to the meridian
something more than 10° lower down than the other star,
according to our latitude. If we were at the equator, it would be
just 10°. This star would set 10° south of west, and so of any
stars whatever, they would all apparently describe diurnal circles,
or parts of such circles, all having the pole of the heavens for
their grand centre. Now at the time of the summer solstice, or
mid-summer, 21st of June, the sun rises directly east, and sets
due west, describing apparently a diurnal circle in the heavens,
after a few days, however, he will rise a little south of east, and
set a little south of west, and in a few days more he will rise still
farther south of east, and set so much south of west, until at the
time of the winter solstice, or mid-winter, he will, in our northern
latitude, rise very far towards the south, and come to the meridian
very low down, and set at as great a distance south of the west
point, as he arose south of the east. Now, if the backward motion
of the sun in the heavens, had been performed in a diurnal circle,
he would rise later and later each day, but always just at the
same distance from the east. Hence we infer, that this
backward motion of the sun, is not in a diurnal circle but inclined
to it. This is the case, the ecliptic, or sun's apparent path,
instead of corresponding with the equator, or with any particular
diurnal circle parallel to the equator, cuts them all at a certain
angle, which angle is called the inclination of the ecliptic. In
order to make this part of our subject clear, we must have
reference to a diagram.

Let P P', be the poles of the celestial vault or concave, having
the earth A, within it, its poles being in the line P P'. As the
earth turns around on its axis, Jet its equator reach the heavens,
marking E E' as the celestial equator. Through a point B, at the
distance of 33|° from the equator, suppose a line B S, which
also passes through the centre of the earth, to reach the sky at
S. As the earth turns around, this line, B S, will mark out a circle
in the heavens, C S, called, for a reason which will soon be given,

THE ECLIPTIC.

57

the tropic of Cancer. A similar line D S, which passes through
J?

the centre of the earth, and a point 23J° south of the equator,
will trace out the circle C' S', called the tropic of Capricorn. .The
circle P E' P' E, will represent a meridian, or a great circle which
passes through the poles and the centre of the earth. Let S S',
be a great circle, (of course seen edgewise in the diagram) this
will represent the ecliptic which is inclined 23|° to the equator
E E'. When the sun is at S in the ecliptic, his apparent diurnal
path in the heavens, as the earth turns around, will be the circle C
S ; and to a spectator at B, the sun would be directly vertical, or
overhead, at noon. If we suppose a little circle marked on the
earth, corresponding with C S, we can readily perceive, that, as
the sun is fixed, while the earth turns around, all those places
upon the %arth which lie in this circle, will have the sun vertical
at noon. But a^ spectator at A, nearer the north pole of the earth,
would have his Zenith, or highest point of the heavens, as at Z,
hence the sun would come to the meridian below the Zenith.
This is the case at all places north of the tropic of Cancer, or
south of the tropic of Capricorn. Suppose now the sun to have
moved in his orbit from S to O, he would then appear to rise at
the same time with the star O, and describe the diurnal circle F
G in the heavens, parallel to the equator, arriving at the meridian

OD THE WORLD.

considerably lower than in the first case. The dotted line POP'
will here represent the meridian, which, it must be remembered,
is not a fixed direction in space, but simply a plane, extending
from the earth to the heavens, and passing through the spectator,
wherever he may be, and the poles of the earth. When the sun,
after moving through one fourth of his orbit, arrives at the point
where the equator and ecliptic cross each other, and which is
called the equinoctial point, the days and nights are equal all over
the world, and the sun is vertical at noon, at the equator. His
apparent diurnal circle will now be the equator E E'. The sun,
still moving on in its orbit, finally arrives at S' its greatest southern
limit, describing the diurnal circle S' C' at the time of the winter
solstice ; after which it again moves northward, rising higher,
and higher, each day, until after a tropical year, it arrives at the
point S, where we commenced. Now if the points S and S',
were fixed points in the heavens, the length of a tropical, or equi-
noctial year, would be the same as the length of a siderial year,
for the equinoctial points are fixed with regard to the tropical
points. It is, for many reasons, more convenient to reckon this
year from equinox to equinox, and hence this is generally termed
the equinoctial year.

Let A B C D, represent the sun's path, inclined 23° 28' to the
equator E D F B, and suppose B, the position of the vernal equi-

PRECESSION OF THE EQUINOXES. 59

nox, and let the apparent positions of the ecliptic and the equator,
or rather portions of them, be represented by the dotted lines, and
suppose some star S, to lie directly in the equinoctial point, or
node, as seen from the earth at H. Suppose the sun, commencing
from the point B, or S, to move around in the direction B A D C,
it is evident, that if the crossing point still corresponded with the
star S, or remained unchanged, the sun would arrive at B, or S,
after an interval equal to a siderial year. But this is not the case,
the plane of the equator E D F B, is not fixed, but while the sun
is performing his journey, it moves slowly backward on the ecliptic
contrary to the apparent yearly motion of the sun in the heavens,
so that, in about .the time of a year, the crossing points are at N
and O, and in the heavens the position of the vernal equinox will
appear to have shifted, contrary to the order of the signs, from S
to' T ; hence, as the sun arrives at T before it can come to S, the
equinoctial year is shorter than the siderial year. This shifting of
the nodes is called the Precession of the Equinoxes, because the
equinox seems to go forward to meet the sun, and thus precedes
the complete revolution of the sun in the ecliptic. Now this

change of place, in the position of the equinox, we infer very

60 THE WORLD.

readily, must be caused by a motion of our earth, for it will be
noticed, that the inclination of the ecliptic to the equator remains
unchanged.

Let ABC, represent the ecliptic, and D B E, the celestial
equator, intersecting each other in two opposite points, one of
which is shown at B. Let P P' be the poles of the earth, 9(P
distant from the equator F V G, in every direction, and let the
star S, in the direction P' P, be the pole of the heavens, every
where 90° distant from the celestial equator, D B E, let the point
T, be the pole of the ecliptic ABC. We must be careful and
not consider the lines F G, H I, marked on the earth as equator
and ecliptic, to be fixed, because this would cause the nodes, or
equinoctial points, to revolve, apparently, once in a day, through
the heavens, but we may suppose them hoops or bands, sta-
tionary, while the earth turns around in them. For a moment
suppose the diurnal revolution of the earth to be stopped, and let
the position of the intersections of the planes of the celestial ecliptic
and equator, meet on the earth at V, and let the poles, of the
ecliptic H V I thus marked on the earth, be O and R, a spectator
at the centre of the earth, would locate the equinoctial point among
the stars at B. If, now, the earth should be turned a little, not on
its diurnal or equatorial axis P P', but on its ecliptical axis O R,
in the direction of the letters C B A, the equinox would appear to
shift in the heavens to the star X, and the pole of the heavens S,
would appear to have moved partly around the pole of the ecliptic
S, and be at Z, This is the fact, whilst the earth is moving around
the sun, and all the time turning daily on its equatorial axis, it is
making a slow backward revolution around its ecliptical axis, and
as the stars are fixed, the equinoctial point continually retrogrades
along the ecliptic, thus causing the pole of the heavens continually
to shift its place, revolving in a circle whose radius is T S, which
is the angular inclination of the axis P P' to the axis O R, or of
the plane of the ecliptic, to the plane of the equator. The early
astronomers, located the places of the equinoxes in the heavens,
and gave the name Aries to the constellation where the vernal,
or spring equinox, was located, and the name Libra to the con-
stellation where the autumnal equinox was located. Since that

•PRECESSION OF THE EQUINOXES. 61

time, the equinoctial point iias retrograded 30°, or one sign, they
whole circle, 360°, being divided into 12 signs of 30° each ;
consequently, the vernal equinox is now in what was then the
last constellation, Pisces, for the stars have not changed places,
only the intersecting point. Astronomers, however, have agreed
to call the point where the vernal equinox is situated, the first point
of Aries, forever, whatever may be the constellation where this
point is located, hence the sign Aries, is now in the constellation
Pisces, the sign Pisces, in the constellation Ag'tiarius, &c. The
annual amount of precession is small, being but 50.1" in a year,
hence the time occupied to make a complete revolution, will be
25,868 years. However, small as it is, it is quite palpable in the
course of a century, and has been of signal aid in Chronology as
we shall show in our chapter upon that subject. As the place of
equinox goes forward each year, to meet the sun, 50.1 seconds of
space, it is evident the tropical or equinoctial year will be as much
shorter than the siderial year, as it takes the sun to describe this
small space, which is 20m 20s, nearly, hence the length of the
equinoctial year is 365d, 5h, 48m, 51.6s, and this is the year which
most intimately concerns us. In ancient times, the days of th»
summer and winter solstice were determined by means of the
shadow of a gnomon, or upright post, as the sun rose higher and
higher each day, at noon, the shadow became shorter and shorter,
until, having reached its limit, it began to lengthen, this was the
day of the summer solstice. The day of the winter solstice, was
the time of the longest shadow. When we look back, and think
of the ancient philosophers, with their shadow-sticks, and rude
dials, and see them trying, with these rough means, to measure
the distances of the heavenly bodies, and the size of the earth, we
may wonder that they ever approximated as near as they did. In
no Science has the advancement of general learning and civiliza-
tion been more apparent, than in Astronomy. Tables of the posi-
tions of the sun, moon and planets, in the heavens, are now given for
many years to come, with such accuracy, that the unassisted eye
cannot detect even their greatest errors, and in some cases, the
positions are given with more accuracy than even could be obtained
from observation itself.

62 - THE WORLD,

The tropical, or equinoctial, or n&an solar year, for these dif-
ferent names all mean the same, is, as we have just shown, about
365| days long. Now if this year was to begin upon the first day
of January, at Oh, Om, Os, the next year must begin January 1st,
at 5h, 48m, 51.6s, or about a quarter of a day later. This would
be excessively inconvenient, hence it was determined to have the
civil year consist of 365 days exactly, and this, for a long period,
was the case, but the consequences, after awhile, became very
apparent. The vernal equinox, which once was at the commence-
ment of the spring months, gradually began to go back, until the
calendar was involved in great confusion. This was especially
the case with the Roman Calendar, in which the year was reckoned
12 revolutions of the moon, or 354 days, and Julius Ca3sar, with
the aid of Sosigenes, an astronomer of Alexandria, attempted a
reformation. The beginning of the year had formerly been placed
in March, by Romulus, in honor of his patron, Mars. Ceesar
determined to commence the year the 1st of January, at the time
of the winter solstice. This seems the most natural time, for
now, the sun, having reached his greatest southern declination,
begins to return, bringing back the spring and summer. Ccesar
chose, likewise, to have, for the first year of the new calendar, a
year when a new moon happened near .the time of the winter
solstice. This occurred in the second year of his dictatorship, and
the 707th from the founding of Rome, when there was a new
moon on the 6th of January. This, accordingly, was made the
beginning of a new year, and in order to make the year commence
at this period, it was necessary to keep the old year dragging on
90 days, or to consist of 444 days. All these days were unprovided
with solemnities, hence the year preceding the commencement
of Caesar's calendar is called the yea* of confusion. To prevent
the recurrence of error, which was what he had most in view, and
keep the civil and astronomical years together, he determined to
add, each fourth year, a day to the calendar, because the solar year
being, as was then supposed, 365| days long, this |, would, in four
years, amount to a day, and could then be added. It was true,
the second year would begin 6 hours too soon, the third would
begin 12 hours too soon, and the fourth 18 hours too soon, but the

JULIAN CALENDAR. 63

commencement of the fifth would correspond with the fifth astro-
nomical year. In the month of February, the lustrations, and
other piaculums to the infernal deities, ceased on the 23d day,
and the worship of the celestial deities commenced on the 24th..
Ceesar chose, therefore, to insert this intercalary day between
the 23d and 24th 'days of February. The Romans did not number
their days of the month as we do now, i. e. 1st, 2d, 3d, &c., but
they called the first day the Calends, from which our word calendar
is derived, thus the 1st day of March was called the Calends of
March, the 28th day of February was called thepridie Calendas
Martias, the day before the calends of March, the 27th was called
the third day of the Calends of March, and the 24th was the sextus,
or sixth day, of the Calends ef March, and as Ctesar's intercalary
day was added just after this day, it was called bissextile, or double
sixth day, and the year in which it was added, received, and still
bears the name, bissextile. Many years after, when Christianity
became the religion of the Roman Empire, Dionysius Exiguus, a
French Monk, after much research, came to the conclusion that
the 25th day of December, of the 45th year of Ceesar's era, was
the time of the nativity, commonly called Christmas, and therefore
the 1st of January, of the 46th year of Caesar, was adopted as the
1st of the Christian era. As the first year of Caesar was a bissextile,
and as every fourth year after the 45th, was a bissextile, conse-
quently the fourth year of the Christian era was a bissextile, and
as every fourth year is the one in which the intercalary day is
added, we can always determine when this year occurs, by simply
dividing the year of the Christian era by 4, if there be no remain-
der, the year is a bissextile,- or leap year, but if a remainder, then
that remainder shows how many years it is from the last bissextile.
The name leap year is given, because the civil reckoning, which
had fallen behind the astronomical, leaps ahead and overtakes it.
The correction introduced into the calendar by Csesar, would
have been sufficient to always keep the astronomical and civil
reckoning together, if the fraction of a day over 365 had been just
6 hours, or | ; instead of this, however, it is but 5h, 48m, 51.6s,
and the difference is llm, 8.4s, which, in 4 years, amounts to
44m. 33.6s, by which amount, the fifth civil year begins later than

64 THE WORLD.

the astronomical year. In 1582 this difference had accumulated,
until it amounted to over 11 days, of course the. equinoxes, and sol-
stices, no longer happened on those days which had been appointed
to them, and the celebrations of the Church festivals, were conse-
quently much deranged. The Council of Nice, which sat A. D.
325, had decreed that the great festival of Easter, should be
celebrated in conformity with the Jewish Passover, which was
regulated by the full moon following the vernal equinox. Now
the decree did not say that this festival, upon which all the others
depend, should be on the first Sunday after the full moon following
the vernal equinox, but on the Sunday following the full moon,
O7i or after the 2isi of March, this being the day, at that time, of
the vernal equinox. Pope Gregory XIII., who occupied the
pontificate in 1582, determined to rectify this error, which was
thus made known, not from any series of observations for that
specific purpose, as at the present day, but by the accumulated
error becoming so great as to introduce confusion. At this time
the vernal equinox really occurred, according to the civil reckoningj
on the llth of March, ten days earlier than the time decreed by
the Nicene Council. To remedy this defect, Gregory directed
that the day following the 4th of October, 1582, should be reckoned
the 15th, instead of the 5th, thus restoring the vernal equinox to
its former position, by omitting altogether ten days. To prevent
the accumulation, he directed the intercalary day to be omitted
on every centurial year ; this would have answered every purpose
if the difference, which had caused the error, had amounted to a
day in 100 years, but it did not, for it was but a little more than f of
a day, hence omitting the intercalary day every 100th, or centurial
year, omitted £ of a day too much, which, in the course of 400
years, amounts to 1 day. It was, therefore, further provided, that
although the intercalary day was ordinarily omitted each centurial
year, it was to be retained every 400th year, thus the centurial
years 1600, 2000, and 2400, are bissextile ; but the years 1500,
1700, 1800, 1900, 2100, 2200, &c., are common years. This
correction is sufficiently accurate for all purposes, the slight re-
maining error will only amount to a day after an interval of 144
centuries. The time of the vernal equinox now is, and always

GREGORIAN CALENDAR. 65

will be, the 21st of March. The correction introduced into the
calendar by Gregory, was not adopted by the English, until the
year 173Q. At this time the difference between the Julian and
Gregorian calendars was 11 days ; it would have been 12 days,
but the latter had omitted the intercalary day in the year 1700, as
we have already stated. It was, therefore, enacted by Parliament,
that 11 days should be left out of the month of September of the
current year, by cabling the day following the 2d of the month the
14th, instead of the 3d. The Greek Church have never adopted
this Romish or Latin correction, and consequently, the Russians
are now 12 days behind us in their reckoning, and the Christmas
festival, which happens with us December 25th, occurs with them
January 6th, or Epiphany day, according to our reckoning, and
which is sometimes, even now, called " Old Christmas day."
The Julian and Gregorian calendars are designated by the terms
" Old Style," and " New Style." Thus, by successive improve-
ments, which have been almost forced upon the world, the calendar
has been perfected, until it answers all the purposes of civilized
life.

"Time," says Young, "is the stuff that life is made of," and
we do well, therefore, not to waste such a precious possession.
We remember the inscription on the dial in the Temple, at Lon-
don : "Begone about your business," a wholesome admonition
to the loiterer, and the no less appropriate device, once stamped
on the old Continental coppers, a dial with the motto, " Mind
your business." There is enough to do, and time enough to do
all that ought to be done. " There is a time for all things," says
Solomon, let us then, be careful and do all things in the proper
time. The French Chancellor d' Aguesseau, employed all his
time. Observing that Madame d' Aguesseau always delayed ten
or twelve minutes before she came down to dinner, he composed
n work entirely in this time, in order not to loose an instant ; the
result was, at the end of .fifteen years, a book in three large
volumes quarto, which went through several editions.

No man, we venture to say, ever accomplished more, and to
the better satisfaction of all interested, than Benjamin Franklin,
another economiser of time. One of his greatest discoveries was

THE WORLD.

made in France, and that was, Sun-light was cheaper than lamp-
light, and better, too. A severe reprimand, -from a man of his
standing, and industry, upon the customs of the French court,
spending the night in mirth and revelry, and sleeping all the day.

It is said there is a moral in every thing, to the moralizing mind.
Since, then, " Time once gone, ne'er returns," let us make the
best use of it ; not sad, or serious, merely, but sober and reasona-
ble -— ready to labor in the hours of labor, and to rest in the hours
of rest. We shall not, then, look back on misspent moments,
with that feeling so aptly expressed in the German : " Ach toie
nichtig, ach icic flucMig /" Ah, how vain, ah, how fleeting !

The flight of Time, which is silently, but surely and uniformly,
bearing us from scenes, loved, perhaps, too well, cannot be too
accurately marked. The correction of the calendar, by Julius
Csesar, has done more to perpetuate his name than the victories
he won for Rome, and the name of Gregory XIII. has more of
meaning in it, than that of a mere Saint, in the Romish calendar.
There is something pleasing, and yet mournful, in thus minutely
contemplating the passage of the year, and we would do well to
imitate the good old custom which our forefathers followed, and
on the first day of the New Year, make the first entry in our new
account books :

Cans 5Deo.

SIDER1AL TIME. ,

CHAPTER VI.

Dials and Dialing.

' This shadow on the Dial's face,
That steals from day to day
With slow, unseen, unceasing pace,
Moments, and months, and years away,
Right onward, with resistless power,
Its stroke shall darken every hour,
Till Nature's race be run,
And Time's last shadow shall eclipse the sun.

67

IN the preceding chapter, we have made frequent use of the
word day, and have throughout meant what is called a mean Solar
day. We have already shown that the Siderial day is the time of
an exact revolution of the earth on its axis. This day is shorter
than the Solar day, by about 4 minutes. We have also alluded
to the apparent motion of the sun in the heavens, showing that if
to-day he came to the meridian at the same time with any particular
star, to-morrow the star would come to the meridian before the
sun, which had apparently changed its place in the heavens. Let
us consider to what the difference between Solar and Siderial time
is really owing, and see how much the Siderial day should be

A

shorter than the Solar, to do which we will have recourse to a
diagram

68 TH

5t A B C D, represent the earth's annual orbit, showing the
in four different positions, and let a be the situation of some
particular meridian, that of Greenwich, for example. Now, on
the supposition that the earth does not rotate on its axis at all,
suppose it moving- in its orbit, in the order of the letters ; it is not
difficult to see that the effect will be the same, as though the earth,
remaining at rest in its orbit, had turned once on its axis during
the year, but in a contrary direction to its present diurnal mo-
tion. Thus, while at A, the sun would be on the meridian1
a, but at B, one fourth of a year after, the sun would set in the
east, and at C, half a year afterwards, it would be midnight at the
same meridian, a~ At D the sun would just begin to rise in the
west, and finally at A would come to the meridian again. It will
now be understood, that although the earth does turn on its axis,
during its yearly circuit, yet this day as really occurs as if the
earth had not the diurnal revolution, hence the number of rotations,
measured by the sun's coming to the meridian, will be less than
the number as announced by a star, by one day, and therefore the
Siderial day must be shorter than a Solar day, by the proportional
part of a revolution, which is thus divided up among, and added
to the 365 Solar days of the year. Upon the supposition that the
mean Solar day is just 24 hours in length, the Siderial day will be,
the one-three hundred and sixty-fifth and one-fourth, of 24 hours,
shorter, i. e. 3m, 5"6s, very nearly,- and a star, in consequence,
will come to the meridian 3m, 56s, sooner than the sun, each
day, or will gain so much on the sun daily.

We have more than once intimated that the time elapsed be-
tween a star's leaving the meridian, to its return to it again, viz :
23h, 56m, 4.,01s, is the precise measure of a rotation of the earth,
and for this reason astronomers prefer to regulate their time keepers
to show what is called Siderial time. Now, suppose to-day to be
the 14th of April, which is near the time of vernal equinox, the
precise point where the ecliptic intersects the equator, we will
imagine to be shown by a bright star. By means of his transit
instrument, the astronomer ascertains exactly when this star is on
his meridian, and just then sets his clock going, the hands showing
at the time Oh, Om, Os, and at the same time the town-clock, we

RIGHT ASCENSION AND DECLINATION', 69

will suppose, or some other time-measurer, such as a watch, o$
ordinary clock, is set going, showing, also, at that instant, Oh, Om,
Os. Now the astronomer's clock is, like the other time-keepers,
divided into 24 hours, only he reckons straight forward from 1 to
24 hours, while in the ordinary time-piece, the hours are numbered
twice in a day, from 1 to 12. We ought to say, however, that the
astronomer begins his day at noon the 14th of April, while the
civil day, April 14th, began at midnight, 12 hours before, but
both clocks now show Oh, Om, Os. The astronomer's clock has a
pendulum a trifle shorter than the common clock, which makes it
oscillate somewhat faster, so that the gain, on the ordinary clock,
may be about 3m, 56s, in a day. After an interval of 24 hours,
by his clock, the astronomer again looks into the transit telescope
and sees the supposed star, or equinoctial point, which is always
called the first point of Aries, just on his meridian, that is, if his
clock is truly adjusted, but it is not yet a day, or 24 hours, by the
civil time, but lacks 3m, 56s. The next dtiy the clocks will be still
farther apart, and in about 15 days there will be 1 hour's difference,
the siderial clock showing Ih, when the ordinary cjock shows
I2h, or noon ; the latter shows the time whea the sun is on the
meridian, or very nearly so, but the former indicates that the first
point of Aries, or the equinoctial point, crossed the meridian an
hour before. Now the great convenience to the astronomer is this:
As the whole heavens appear" to revolve around the earth in a
siderial day, he imagines a circle traced out in the heavens, which
corresponds to our equator, and, commencing at the vernal equi-
noctial point, or first point of Aries, he divides this celestial equator,
into 24 equal portions, or hours, and these he subdivides into 60
minutes, and each minute into 60 seconds, and he calls the distance
of any body from this first point of Aries, measured on the celestial
equator, just as we measure longitude en a globe, or map, by
ascertaining how far east or west the place is from Greenwich,
measured on the terrestrial equator ; this he calls the Right As-
cension of that body, designated by the initials R. A., and the
distance of the body north or south of the equator, he calls De-
clination, north or south, designated thus: N. D., or S. D.,
corresponding with our geographical terms, north and south

70 THK WORLD.

latitude. The only difference between longitude as reckoned on
the earth, and right ascension as measured in the heavens, is,
the former is reckoned east or west from any arbitrary point,
Greenwich, or Washington, for example, but the latter is reckoned
eastward, or in the order of the signs, completely around, and
always from the first point of Aries, which is a determined point
in the sky, being the position of the vernal equinox, and which
turns around, apparently, with the whole celestial concave, in its
diurnal revolution.

When a new comet appears, and is announced as having a R.
A. of 6h, and 10m, and N. D, of 2° 15', the astronomer places his
transit telescope, or .other similar instrument, so as to point 2° 15'
north of the imaginary celestial equator, for he knows just how
high above the horizon this is situated, and when his clock points
out 6h and 10m, he looks into the telescope and sees the newly
discovered object. Thus the precise position occupied by any
star, or planet, in the heavens, can be mapped down, using right
ascensions and declinations in the same manner as terrestrial
longitudes and latitudes. We should like to say a great deal more
on this subject, buj, the nature of our work forbids.

Our ordinary clocks and watches, are adjusted to keep mean
solar time.. It would, at first, be supposed, that the interval from
noon to noon, although longer than a Siderial day, would, never-
theless, be an equal period, so thafif a clock was adjusted to show
24 hours during the interval of the sun's leaving the meridian at
any particular season of the year, to his return to it the next day,
it would always indicate an interval of 24h, for any similar revolu-
tion. This is not the case, and we think we can show, very
plainly, why it is not. The instaht when the sun is actually on
the meridian, is called the time of apparent noon, or 12 o'clock
apparent time, although, a clock regulated to keep what is called
mean time, or mean solar time, may then show but llh, 45m.
The difference between apparent time and mean solar time, is
called the equation of time, i. e. the correction which must be
applied in order to determine true time, from the time indicated
by the sun. It is evident that Sun-Dials will indicate apparent
time, and we will, therefore, devote the remainder of this chapter

SUN-DIAt.5,

71

to a description of the principles of dialing, and then proceed to
illustrate the causes, which make the discrepancy observed between
the times indicated by a clock supposed to run with an uniform
motion, and a good sun-dial. We do this the more willingly,
for we intend our book to be of some advantage to the reader, and
we trust that after its attentive perusal, he will feel sufficiently
interested to either erect a good dial, or a meridian mark, in order
to determine his local time with something more of accuracy
than suffices for the ordinary wants of life. We mean by local
time, the correct solar time for the place, in distinction from
Greenwich time, or Siderial time. Chronometers, which are
accurate, but portable, time-keepers, are of4en set to Greenwich
time, L e. they are adjusted so as to show, wherever they are
carried, the actual time then indicated by the clock at Greenwich,
the difference between this and the time indicated by the clock at
any other place, or the local time will give, by simple inspection,
the difference of longitude.

Let P A B C, be the earth, and E the position of a spectator
upon it, and let F G be the horizon, or a horizontal circle, and let
C H A be the plane of a great circle parallel to the small circle F
G, and let P B be the axis of the earth inclined to the diameter

72 THE WORLD.

C A of the great circle C H A, according to the latitude of the
spectator E. Now as the earth turns once on its axis in 24 hours,
it is evident that the several meridians P, P I, P II, PHI, &c.,
will come successively under the sun at exact intervals of 1 hour,
if they are all 15° apart, for 24 multiplied into 15 gives 360, the
whole number of degrees to the circle. Suppose, for a moment,
that instead of the earth turning up on its axis, once in 24 hours,
that the sun moves around the earth in this time, the effect will
be the same If the sphere of the earth was transparent, but its
axis P D B opaque, then P D would, as the sun passed around,
cast a shadow in the directions D A, DI, DII, Dili, &c., when
the sun was in the apposite direction, and the progress of this
shadow would mark the hour, according to the meridian in which
it should fall. It will be observed, that the intervals A-I, I-II, II-
III, are not equal intervals, but vary, because the circle C H A,
cuts the meridians obliquely. Now the sun is so far distant, that
if the observer at E should locate a horizontal plane, which, of
course, would be parallel to the large plane C H A, and describe
on it a small circle, and then divide this circle in proportion as
the meridians divide the large circle C H A, and should, likewise,
erect from its centre a gnomon, or shadow stick, inclined so as to
point to the north star, or in other words, to be parallel to P D, the
progress of this shadow would mark the hour. We have here,

then, the principle of the horizontal Sun-dial, and all that is
necessary to construct one, is, to graduate it proportionally accord-
ing to the latitude. This can easily be done by calculation, which,
however, would involve more of mathematical skill than we shall
suppose the reader to possess ; we will, therefore, show how it
may be done experimentally, and thus any one, with the least
ingenuity, can construct a horizontal dial. Referring back

DIALING. 73

to the figure, page 71, it will not be difficult to perceive that if the
circle C H A, had been the equator,. then all the angles of the
hour lines D A, D I, D II, &c., would have been measured by
equal arcs, each 15°. The same would 'be true of any small
circle, I K, parallel to the equator* the meridians, 15° apart, would
divide it into 24 equal parts. Now, if on a globe, we should
divide any parallel of latitude, such as I K, before alluded to, into
24 equal parts, and then pass a plane, a sheet of paper for example,
through each of these divisions and the centre of the globe, then,
wherever this plane intersected the plane of any other circle, C
H A for example, it would mark out the directions of the hour
lines D A, D I, D II, D III. &c. Take, BOW, a flat board, on
which a sheet of paper is fastened, and describe a circle whose
centre is O, as in the diagram below, and let O B be a metallic

rod, inclined to the line A C, drawn on the paper to represent a
meridian line, at an angle equal to the latitude of the place, let
D E be a small circle, so fixed on O B, that its plane is everywhere
perpendicular to it, or in other words, so that the distance from
the point B to the circumference of the circle, may be the same
throughout. Let this smaller circle be graduated into 24 equal
parts, and subdivided into halves, and quarters, and if desired,
still smaller spaces. Take, now, a fine thread, or a straight edge,
and carry it from B through each division of the little circle,
successively, down to the plane of the paper below, taking care, if
a thread is used, not to crooR it against the edge of the little circle,
but simply passing it straight down. Through the points F, G, H,

74 TIIK WORLD.

I, &c., thus indicated on the paper, and the centre of the circle A,
draw the hour-lines A F, A G, A H, &c., extending, however,
only to the circumference of the circle, and we have a dial «ready
for use, after adding the figures. Of course the little chicle must
be so adjusted that when the line is passed by some one of its
graduations, it will reach the horizontal plane at a point in the
meridian line A C. Instead of a wire for the gnomon, we may
use an inclined plane, so that our dial will now be not unlike this

-•'. :" - '' -

figure. In order to use it, we must next determine the north and
south line, or a meridian line, and place the lino on our dial which
marks XII, to correspond therewith. This may be ascertained
by means of a surveyor's compass, provided the variation of the
needle from true north is known ; or, at the time of the solstices,
mid-summer or mid-winter, when the sun's declination is
changing very slowly, a number of circles may be traced upon a
horizontal plane, having a 'common centre, over which centre a
plumb-line must be suspended, having two or three knots tied in
it. Upon marking where the shadow of these knots falls, suc-
cessively, on the circles, in the forenoon and afternoon, and then
bisecting the space so measured on each circle, and drawing a
line through the centre and these points of bisection, a pretty
exact meridian line may be laid down. The use of several circles,
is simply to ensure greater accuracy in the result. We will now
suppose the dial constructed, and located in a window facing to
the south. We may here observe, that there will be no use in
graduating the dial all the way round, as that portion only can be
used over which the shadow passes during the day, say from 5
o'clock to 5 o'clock, on each side, viz : from V, on the western
side, through VI, VII, VIII, IX, X.-XI, to XII, and from XII, to
V, on the eastern side. When the sun rises before 6 o'clock, say

DIALS AND CLOCKS. 75

at 5 o'clock, it will then be shown at V, by the shadow on the
western side of the dial, and the shadow cannot be observed on the
dia>to advantage much later than 5 o'clock, Suppose, then, the
dial located, and that when the shadow indicates XII, or apparent
noon, a well regulated clock is started, the hands of which also
indicate XII, and this on the 24th day of December, for, as we
shall soon see, this is one of the four days in the year when the
clock and dial agree, then, although for a few days, the clock and
dial will .appear to indicate the hour of noon together, it will soon
be observed, that the clock begins to gain on the dial, and after
an interval of one month, the clock will show 12h, 13m, when the
dial indicates noon, or 12 o'clock apparent time. This difference
will go on increasing, until February 10th, or llth, when the
clock will appear to lose time, and by the 25th of March will be
only 6m. faster than the dial, and on the 15th day of April they
will again correspond. The clock, after this, will continue, appa-
rently, to lose time until about May 15th, at which time it will
only indicate llh, 56m, when the dial shows noon ; after this, its
rate seems to increase, and on the 16th day of June they again
come together. The clock now continues to gain on the dial until
July 25th, when it is about 6m, 4s, faster, after which, its rate
apparently decreases, until at August 31, they again coincide.
On the 2d of November, the clock shows llh, 43m, 46s, when
the dial says it is noon ; this is the greatest difference of all, being
16m, 14s, after this they begin to come together, and on December
24th, again correspond. Now, can it be that the sun's motion in
the heavens, or rather the earth's motion, is thus irregular ? We
might, at first, suspect our clocks, and watches, but the utmost
pains have been bestowed on these, and when their rates of going
have been ascertained, by means of the stars, and a transit instru-
ment, as already described, they are found to go perfectly uniform,
or very nearly so. Hence we are forced to admit, that the dis-
crepancy between the dial and the clock, is to be sought for in the
movements of the earth, and we shall fully show, in our next
chapter, what these are.

Thus far we hope we have succeeded in explaining the phe-
nomena of the heavens due to the movements of the earth, nnd

76 THE WORLD.

we have, we trust, been sufficiently clear. If, in some parts, we
have been tediously minute, the more intelligent reader will
remember we are writing for those who may be less expert.
Certainly every one must feel interested in understanding the
causes of some of the most striking phenomena which are con-
tinually occurring. The varying lengths of days, the annual
round of seasons, the constant return of day and night, the tides,
the winds, and the clouds, all these force themselves upon
observation, and demand some attention. To the consideration
and elucidation of these great phenomena, the wisest men of all
ages have devoted their lives, and simple and clear as the illustra-
tion of these great natural causes may now appear, they have cost
an amount of human labor and severe study, which we might in
vain attempt to estimate. We feel not the less satisfaction, that
we can look beyond the occurrences of the day and understand
the causes which are concealed from careless eyes. The earth
is no less beautiful, and beloved by us, because we can look above
and see worlds, which we know to be a thousand times larger,
and on which, we sometimes fancy, myriads of intelligent beings
are existing, all pursuing the same great ends as we. After all,
we are well satisfied with the study of our own planet, and find
enough upon its surface, or below it, to fill us with admiration and
wonder, and see enough in it of beauty, whether glowing in the
warm sun-light, or reposing in the, quiet rays of the moon.

ORBIT OF THE EARTH. 77

CHAPTER VII.

Measurement of Time.

" The Pilots now their rules of art apply,
The mystic needle's devious aim to try;
Along the arch the gradual index slides,
While Phoebus down the vertic circle glides,
Now, seen on ocean's utmost verge to swim,
He sweeps it vibrant with his nether limb.
Their sage experience thus explores the height
And polar distance of the source of light."

Falconer.

HITHERTO we have spoken of the earth's orbit as circular, such
being its apparent projection upon the celestial sphere, but this is
not the actual case, it is elliptical. This is ascertained by the
change in the apparent diameter of the sun, viewed from the
earth at different seasons. If the orbit of the earth was a great
circle, having the sun in its centre, it is obvious that the angle
subtended by his disk would at all times be the same, for his dis-
tance from the earth would always be the same. On the contrary,
the diameter is observed to increase from the summer solstice to
the winter solstice, then to again decrease. It is a proposition
established in optics, that the apparent diameter of an object,
varies inversely as the distance frcyii the spectator, when the angle
is small, hence by observing with great accuracy, the apparent
diameter of the sun, at different periods of the year, and actually
projecting or calculating the orbit of the earth, it is found to be an
ellipse, or oval, as represented in the following diagram.' The
sun being situated, not in its centre, but nearer one side, in what
is called one of the foci of the ellipse. The foci of the ellipse S
and C, are so situated on the major, or longer axis, of the ellipse,
that the sum of the length of any two lines drawn from the foci to
the same point in the circumference of the ellipse is constant.
Thus the sum of the lengths C E and S E, are equal to the sum of

73

THK WOTU.I).

the lengths C O and S O, or C D, and S D, and all are equal to the

length of the major axis A B. By placing two pins, one at eacli
focus of the ellipse, and tying a thread around them of such length
as will give the requisite major axis, a true ellipse may be described,
by stretching the string and moving a pencil around in the angle.
In the preceding diagram, we may suppose S E C, S O C, S I)
C, to be three positions of the string, the pencil being placed in
the angles E, O, and D. Such is the peculiar property of the
ellipse, and in such an orbit the earth is moving around the sun.
Let S be the position of the sun, and A the position of the earth,
at the time when nearest the sun, and when, consequently, the
sun's diameter appears the largest. This point in the orbit, is
called the perihelion point, from two Greek words, which mean
near or about the sun. The point B is called the aphelion point,
or point away from the sun ; when the earth is in this position,
the sun's diameter appears the. smallest. The line B A, is called
the line of the apsides, La. the line without deviation, or change
in length, for we shall show, presently, that whatever changes the
earth's orbit may undergo, tlys line will remain unaltered. In
the preceding chapter, we observed that the sun's motion was
not uniform in the heavens, or did not correspond with the indi-
cations of a well regulated clock. It will not be difficult to under-
stand, that since it is the attraction of the sun which causes the
motion of the earth', it will, while approaching the sun, have its
motion continually accelerated, or quickened, until it sweeps
around the perihelion point A, with its greatest velocity, itfi motion

DIALS AND CLOCKS. 79

will then decrease, and it will move slowest when it passes the
aphelion point B. The earth is at the point A, on the 31st of
December, and at the point B, six months after, or July 1st, If
the inequality between the time indicated by the dial and that by
the clock was caused wholly by this change in the velocity of the
sun, then the dial and clock should agre% exactly when the earth
was in these two positions, for the earth occupies just 6 months
in moving from A to B, and 6 months in .returning from B to A,
just what it would if its orbit was a circle, and in which case the
dial and clock would agree. But by actual observation, the dial
and clock are not together twice in the year, but four times, and
then not when the earth is at A and B, December 31, and July
1st, but on December 24th, April 15th, June 16th, and August
31st, as we have already intimated. We must look, therefore,
to another source, which, united with the one we have just con?
sidered, will fully explain all the observed phenomena, and we
find it in the inclination of the sun's apparent path to the equator,
As the earth turns on its axis, we may suppose a rod which ex-
tends from the centre of the earth, and through its equator to the
sky, tracing out a line, or circle, in the heavens, which is called
the celestial equator. This circle is, as we have already shown,
divided into 24 parts, called hours, each hour comprehending 15°,
and all these spaces are exactly equal. If the sun's yearly path
in the heavens had corresponded with the equator, or had been in
the same plane, then all the difference between the dial and clock
would have been simply what was due to his moving sometimes
apparently faster than at others, in consequence of the earth's
elliptical orbit, but this is nofthe case, the plane of the ecliptic, or
sun's path, is inclined to the plane of the equator. Now, on the
supposition that the orbit is circular, let us see what effect this
would have upon the sun-dial. In the next diagram, the circle
0, 1, 2, 3, 4, 5, &c., which are hour divisions, represents the
equator, and I, II, III, IV, V, VI, &c., which are also hour di-
visions, the ecliptic. Clock time is measured on the former, for
this is the circle, or others parallel to it, in which the stars, and
other heavenly bodies, seem to move on account of the diurnal
rotation of the earth. Dial time is measured on the ecliptic, and

THE WORLD.

we have just shown that the dial was graduated, or marked, with

unequal divisions on this very account. The little cross strokes
at II, IV, VI, &c., indicate the position of the sun each month
from the vernal equinox, P is the north pole of the heavens, and
P 1, P 2, P 3, &-c. are meridians cutting the ecliptic I, II, &c. above
the equator ; 0 is the place of vernal equinox, VI the position
of the summer solstice, XII the place of the autumnal equinox,
and XVIII of the winter solstice. On the 2d day of May, which is
about midway between the vernal equinox and the summer sol-
stice, the sun would be at the point III, but if it had moved over
three equal divisions of the equator, it would be at 3, and now if
a meridian be passed through 3, as at P 3, it will intersect the
ecliptic beyond III, i. e. on the side towards IV. Now III being
the place of the sun, if we suppose a meridian passing through P
and III, it will intersect the equator on that side of 3 towards 2, i. e,
the sun would come to the meridian by the dial before it would by
the clock, for the dial will show 12 o'clock, when the meridian,
which passes through III, is in the mid-heavens, at any place,
but the clock will show 12, when the meridian, which passes
through 3, is in the mid-heavens, and this would be after the dial.
On the supposition that the earth's orbit is circular, the dial and
clock would now, when the* sun is at III (May 2d), be farthest
apart, after this they would come together and correspond at VI,
and 6, the time of the summer solstice, after this the clock would

LONGITUDE. 81

be faster than the dial till the time of the autumnal equinox, then
slower till the winter solstice, and again faster till the vernal equi-
nox. The earth's orbit is not a circle, but if the line of apsides A
B, see figure on page 78 corresponded with the line VI-XVIII, in
direction, then the clock and dial would agree at the time of winter
and summer solstice, i. e. December 23, and June 21st, but it
does not, for we have seen that the earth is in perigee December
31st, and in apogee July 1st, hence, in forming a table to show the
equation of time, i, c, the correction that must be applied to the
dial, or apparent solar time, in order to obtain true solar, or what
is called mean time, which is the time in ordinary use, we must
compound the two inequalities, for sometimes when the dial
would be fastest, on account of the unequal motion of the sun in*
his apparent orbit, it would be slowest from the effect of the incli-
nation of the plane of the ecliptic, to the plane of the equator,
thus, April 15th, the dial will be slower than the clock, from the
inequality of the sun's motion, about 7m, 23s, and at the same
time it will be faster, from the obliquity of the ecliptic, about the
.same amount, hence they are really together on that day. The
tables of the equation of time, are thus constructed. We have
now explained, somewhat at length, the method of obtaining true
time, from the time indicated by the sun, for it is of the utmost
importance to the astronomer, and the navigator, to be able, on
all occasions, to determine the local time.

It must be evident, that inasmuch as the earth is round, the sun
will appear, as the earth turns on its axis, to rise and come to the
meridian successively at every point upon its surface. If, therefore,
some particular spot, Greenwich for example, is chosen, whose
meridian shall be the one from which the time, or longitude, is
reckoned, then if we know what time it is at that meridian, when
the sun happens to be on the meridian at another place, we can,
at once, by taking the difference between the times, viz : noon at
that place, and, perhaps 4 o'clock P. M., at Greenwich, determine
that it is 4h, west of the meridian of Greenwich, or, allowing 15°
to the hour, 60° west. The meridian of Greenwich, where the
Royal Observatory is located, is generally acknowledged as the
first meridian, and longitude is reckoned east or west from it. In

82 THJi WORLD.

the United States, the meridian of Washington is very often used.
Navigators are accustomed to carry with them Chronometers,
or very accurate time-keepers, which are set to Greenwich time,
and give,' at any moment, by simple inspection, the precise time
which is then indicated by the clock at Greenwich. On a clear
day, the true time on ship-board, or the exact instant of apparent
noon, is ascertained by means of the quadrant, figured below.
This is an arc of a circle, embracing something more than one-
eighth of the whole circle, but it is graduated into 90°, for the
degrees are only half the length they would be, if the angles were
measured without being twice reflected.

A is called the index glass ; it is a plane quicksilvered glass
reflector, placed, by means of adjusting screws, truly perpendicular
to the plane of the quadrant, and attached to the brass index arm
A B, thife index turns on a pin directly under A. C is called the

QUADRANT.

horizon glass, and is also adjusted to be perpendicular to the plane
of the quadrant, the upper part of this glass is unsilvered, so that
the eye, applied at the eye-hole D, -may look through it. The
index A B, carries, what is called a vernier, which subdivides
the graduations on the limb of the instrument E F, into smaller
portions, usually into minutes. When the index is s6t to 0, and
the eye applied at D, the observer will perceive, if he looks through
the horizon glass at the horizon, that the portion of the horizon
glass which, being silvered, would prevent his looking through,
will, -nevertheless, show the horizon in it almost as plain as if it
was transparent, it being reflected on to it by the index glass A,
and then again reflected to the eye, thus, Fig. 1, A is the index

(Fig. I). (Fig. 2).

glass, its back being towards the eye, and C the horizon glass, and
D E the horizon, Seen almost as plain wthe silvered portion of C,
as through the transparent part. If the glasses are all rightly ad-
justed, then, even if the position of the quadrant be altered, as in
Fig. 2, the line of the horizon will still be unbroken, but move the
index ever so little towards 1°, or 2°, and immediately the reflected
image of the horizon will sink down, as shown in this diagram,

a space equal to that moved over by the index, and if a star should
happen to be just so many degrees, or parts of a degree, above

84 fHE WORLtK

the horizon, as the index had been moved, and as shown at a, it

would appear in the quadrant, as in the figure preceding,brought
to the line of the horizon. Now just before noon, on ship-board,
the sailor sets the index of his quadrant to about the altitude of
the sun, and defending the eye by a set of dark glasses, shown at
G, page 82 he looks through the eye -hole D, and the unsilvered
portion of the horizon glass, and sees a distinct image of the sun,
almost touching the horizon, thus :

It is true, he cannot see the horizon in the silvered portion of the
horizon glass, but he can bring the image close to the line where the
silvering is removed from the glass, and then by inclining his qua-
drant a little, as in figure 2, page 83, he can make the sun, appa-
rently, describe the dotted arc c d, just touching the horizon. We
will suppose he is looking just before noon, i. e. before the sun
comes to the meridian, or reaches his highest altitude in the
heavens, and that an assistant stands near, ready to note the time
when this highest point is reached. As he looks through his
quadrant, the image of the sun, which a moment before described
the arc c d, and appeared to touch the horizon in its course, will
seem to rise a little, he therefore moves the index, and brings it
down again, all the time sweeping backward and forwards ; if it
rises a little more, he again brings it down, very soon he perceives

APPARENT TIME. 85

it to be changing its position scarcely at all, and gives notice to the
person with the watch, or chronometer, to be ready; in a moment,
instead of rising, as before, it begins to dip below the horizon,
and he calls out, and the time is accurately noted. This is the
exact instant of 12 o'clock, apparent time, or the instant when the
sun, having reached its highest point, begins to decline. Now
the chronometer, with which he has been observing, does not say
12 o'clock, but perhaps, 3h. 5m. 10s. in the afternoon. We will
suppose the observation to be made on the 27th day of August.
On this day, as will appear from a table showing the equation of
time, a clock adjusted to keep true solar time, should show 12h,
1m. 10s. at apparent noon, and this is the time which the clock
would show at Greenwich, at apparent noon there upon this day;
but when it is apparent noon at the place where we have just
supposed an observation made, the Greenwich clock shows 3h.
5m. 10s., the difference is 3h. 4m., which, allowing 15° for each
hour, indicates that the observation is made in a place 46° west
of Greenwich. It is west, because the sun comes to the meridian
later than at Greenwich. Now if the latitude was known by ob-
serving the altitude of the polar star, then, by referring to a chart,
the position, either on ocean or land, where the observation was
made, could be indicated; for all charts, or globes, which represent
the earth's surface, have lines drawn upon them, through the
poles, called meridians, showing every degree east or west of
Greenwich, and also every degree north or south of the equator.
We will close this somewhat tedious chapter, with an allusion
to a circumstance which has sometimes puzzled the uninitiated,
viz : two ships may meet at sea and vary in their reckoning a day
or two. Suppose a traveler, leaving New York on a certain day,
to travel continually east, until after a certain time, one year,
or perhaps twenty, he arrives at the place from which he started;
and farther, suppose he has kept an accurate note of the number
of days which has intervened. For every 15° he has traveled
east, the sun has risen one hour earlier to him than to those
left behind. This gain, by the time he has traveled 360°, amounts
to a whole day, and when he arrives home he finds his reckoning
one day in advance of his neighbors, or in other words, he has

86 THE WORLD.

seen the sun rise once more than they have. The year to him
has consisted of 366 days, but to his neighbors of only 365- Now,
what is not at all an improbable case, we will suppose him
arriving home on a leap year, on the 28th day of February, and
which he calls Sunday, the 29th, but those who have remained at
home call it Saturday. The next day, February 29th, is, according
to them, Sunday ; here is another Sunday in February, but there
have already been four others, viz : the 1st, the 8th, the 15th, and
the 22d, making six Sundays in this shortest month. It is said
that this case has actually occurred ; that a ship left New York on
Sunday, February 1st, and sailing eastward continually, arrived
home, according to her log-book, on Sunday, the last day in the
same month, but really on Saturday, according to the reckoning
at home. The next day, being the intercalary day, made the
28th,' and 29th both, Sundays to the voyagers ; thus giving six
Sundays to the month. If, on the contrary, a voyage had been
made westward, one day would have been lost in the reckoning,
as the sun would rise one horn1 later for each 15°, and if two
travelers should leave the same place, say on Tuesday, and each,
after passing completely around the globe, the one east, and the
other west, should again meet at the same place, there would be
a difference of two days in their account, the one calling the day
Monday and the other Wednesday, when, in reality, it would be
Tuesday.

CHROMOLOGY. 87

CHAPTER VII.

Chronology.

44 Brightly ye burn on heaven's brow ;
Ye shot a ray as bright as now,
When mirrored on the unruffled wave
That whelmed earth's millions to one grave."

E. P. Mason.

WK have more than once mentioned the importance of the
movements of the heavenly bodies, in determining certain chro-
nological questions, and will now give some farther illustrations
of this subject. The precession of the equinoxes, and the occur-
rence of solar and lunar eclipses, are the two astronomical
events which have been of most essential service. We have,
in the preceding pages, illustrated the precession of the equinoxes,
showing that the places of vernal and autumnal equinox, or the
points where the ecliptic intersects the plane of the equator, moved
westward at the rate of 50| seconds of arc in one year. The
phenomena of solar and lunar eclipses, we have not explained,
nor does it fall within the limits wre have prescribed to our little
volume, to embrace them. We shall, therefore, only refer at
present, to the service which chronology has received from the
knowledge of the retrogradatioii of the nodes of the earth's orbit,
on the ecliptic. As already shown, the path of the ecliptic in the
heavens, is divided into 12 equal parts, of 30° each, called signs,
and these signs formerly gave the names to the constellations, or
groups of stars near which they were located, when the ecliptic
was thus first divided or portioned out. That point in the ecliptic
where the vernal equinox is located, was then, and has been
always, designated as the first point of Aries, but as this equi-
noctial point changes its position, moving contrary to the order of
the signs in the ecliptic, at the rate of 50.2 seconds a year, the first
point of the sign Aries no longer corresponds with that group of

OO THE WORLD.

stars to which it formerly gave a name, for the shifting of the
equinox cannot carry forward the stars with "it. The vernal equi-
noctial point is now situated in the constellation Pisces, having
altered its position about 30° since the constellations were grouped
and named in their present order. As we know the annual
amount of the precession, we can determine how long ago the
present zodiac was formed, viz :

50.2" : 1 year : : 30° (=108,000"): 2155.6 years,
that is, about 300 years before the Christian era, when the most
celebrated astronomical school of antiquity, flourished under the
auspices of the Ptolemies, and the labors of the astronomers of
that school, the most celebrated of whom was Hipparchus, who
formed a catalogue of the stars, were recorded in the Ahnagest of
Ptolemy, and constituted the chief knowledge upon this subject,
until the times of Kepler, Tycho Brahe and Copernicus. The
conclusions which we may come to, from ancient astronomical
observations, are necessarily liable to some error, from the im-
perfect manner in which their observations were made, most of
them having been 1?ut approximations, and not very close ones,
to the truth. We have illustrated, (page 60), in what manner
the precession of the equinoxes causes the pole of the heavens to
revolve around the pole of the ecliptic, the effect of which is, that
successive stars, which lie in the circumference of the circle
which the pole of the heavens thus describes, will, in succession,
become the pole star. The present polar star was not always the
pole star, nor is it as near the true pole of the heavens now, as it
will be. In about 240 years, it will be but 29' 55" distant from
the pole. At the time of the earliest catalogues, it was 12° dis-
tant, and now, 1848, its distance is about 1° 25'. About 2900
years before the commencement of the Christian era, the bright
star in the tail of Draco, called Alpha, was the polar star, and was
then only 10' from the pole ; and in 11,600 years, the bright
star Lyra, will become the polar star, and will then be but 5° from
the pole, whereas, its distance now is upwards of 51°. We give
on the next page, a representation of that part of the heavens
where the north pole of the ecliptic is situated.

Here we have the pole of the ecliptic fh the centre, and the

POLE OF THE ECLIPTIC.

89

pole of the heavens, or that part of the heavens towards which
the pole of the earth points, at the top, directly where the line VI-
XVIII crosses the outermost circle drawn around the pole of
the ecliptic, and which is the little circle represented in the figure,
(page 59), with the radius T S, or T Z. The pole of the earth, as

it revolves around the pole of the ecliptic, passes, in succession,
through each point of this circle, moving, as represented in the
map, towards the left. This circle we have graduated into spaces
of ten degrees each, and drawn meridians from the pole of the
ecliptic through them, the pole of the heavens moves over one of
these spaces in about 718 years. The meridian VI, XVIII, is the
only one which passes through the two poles, consequently when
Polaris comes to this meridian, its distance from the pole will be
the least possible. In the course of 2100 years, as will be perceived,

90 THE WORLD.

the star called Gamma, in the constellation Cepheus, will be the
pole star. The meridian VI, XVIII, is called the solstitial colure,
because it is the meridian which passes through the highest and
.lowest points of the ecliptic, which are called solstices, being the
meridian 18, P, 6, of the figure on page 91.

We will now give some instances of the application of the pre-
cession of the equinoxes to chronology. Eudoxus, a celebrated
Greek astronomer, informs us, that in the celestial sphere, he had
observed a star which corresponded to the pole of the equator.
From various circumstances, we know Eudoxus lived about
the fourth century before Christ, hence it could not be our present
polar star which he observed, for at that time it was too far re-
moved from the pole. Upon reckoning back about 2000 years,
however, upon our man, we find a small star of the fifth magni-
tude, which may be the one observed by Eudoxus.- We are of
opinion that this star is the one meant by him. Others, however,
supposing Eudoxus to have borrowed his sphere from some older
source, have selected Kappa, in the constellation Draco, as the
star. This latter was the pole star about 1310 vears before Christ,
but in the time of Eudoxus, it was as far distant from the pole,
nearly, as was our present polar star. The little star we have been
considering, was the pole star about 200 years before the Christian
era, and as it is easily visible to the unassisted eye, was probably
the star meant by Eudoxr,?.

The effect of the precession of the equinoxes, is to change the
right ascensions and declinations of the stars, for, as we have
more than once observed, right ascension is the distance from the
first point of Aries, but this point is continually changing its place
in the heavens. It also changes what is called the longitude of
the stars. The longitude of a star, is, like right ascension,
reckoned from the first point of Aries eastward, but upon the
ecliptic instead of the equator, thus, 0° of R. A. and 0° of Long,
are both reckoned from the same point. See the next figure,
where the right ascension is marked 0, 1, 2, 3, 4, &c., and
longitude is marked 0, 1, II, III, IV, &c. Declination is distance
north or south of ftie equator, but latitude is distance north or
south of the ecliptic, hence, when a star happens to be in the

PRECESSION OF THE EQUINOXES.

meridian called the equinoctial colure, or meridian which passes
through the equinoxes, a part of which meridian is seen at P O, its

declination and latitude will be pretty near the same, but if the
star happens to be in the solstitial colure, the latitude will vary
from the declination, by the amount due to the obliquity of the
ecliptic, being either more, or less, according to the position of
the star, and whether the latitude is reckoned north or south. It
will also appear that the latitude of a star is not altered by preces-
sion. Imagine, for a moment, the system of meridians, and the
ecliptic and equator, entirely detached from the stars, and moved
slowly around, not the pole of the earth, which we will imagine
within it, but the pole of the ecliptic H. It is easy to conceive
that a star which is in the equator, say at the point 2, would no
longer be in it, but a star at II, in the ecliptic, although its distance
from the vernal equinox would be increased, would still be in the
ecliptic. The same is true of all small circles parallel to the
equator and ecliptic, the former called declination circles, and the
latter parallels of latitude. Perhaps we have been tediously mi-
nute, but there is some satisfaction in understanding a difficult
subject, and if the reader has had like patience with ourselves,
we trust the time will not be spent in vain. The grand point at
which we have been aiming, after all, is this : if we can find any
ancient records of observations which give the longitudes of the
stars, we can tell the dates of the observations. It is well known
Chat the ancients did not. possess a uniform system of chronology

92 THE WORLD.

like ourselves, but they endeavored to perpetuate the memory of
great events by recording the positions of the heavenly bodies at
the time ; and in this, at least, they exhibited wisdom. We find
continual evidences of this, particularly in the poets of those earjy
ages. The Egyptians, to whom the overflowing of the Nile was
an annual, and in some respects, a dreaded occurrence, were ac-
customed to watch for the heliacal rising of the dog-star, which
warned them to gather their wandering flocks and herds, and
prepare for the coming flood. Hence, that star was called Thoth,
the watch-dog, the Guardian of Egypt.

The stars rise or set heliacally, when they rise just before, or
set just after the sun. They are said to rise or set cosmically,
when they rise or set just at sunrise, and to rise or set acronycally
when they rise or set just at sunset. It will appear that the heliacal
rising, or setting, will precede or follow the cosmical rising, or the
acronycal setting, by about 12 or 15 days, for a star cannot be seen
unless the sun is 12° or 15° below the horizon, and the sun
moves over about a degree in a day. Pliny says that Thales, the
Miletian. astronomer, determined the cosmical setting of the
Pleiades to be 25 days after the autumnal equinox. At the present
time, the same event occurs about 60 days after the equinox,
making a difference of 35 days, which, allowing 59' to a day,
makes 34° 25' change in longitude, due to the precession of the
equinoxes. This, divided by the annual precession, 50.2", gives
about 2465 years since the time of Thales, or 620 years before
Christ. We find, also, in Hesiod, the number of days after the
winter solstice, when Arcturus rose acronycally,

" When from the solstice sixty wintry days
Their turns have finish'd, mark, with glitt'ring rays,
From Ocean's sacred flood, Arcturus rise,
Then first to gild the dusky evening skies."

But as we know the latitude of Bccotia, where Hesiod lived; we
can determine the acronycal rising of Arcturus, and by means of
the difference between the time how, and the time mentioned by
him, which is due to precession, can determine the age in which
he flourished. From actual observation, it is ascertained that now
this star rises at sunset about 100 days after the winter sclstict.

PRECESSION OF THE EQUINOXES. 93

The difference, 40 days, converted into degrees, allowing 59' for
a day, is 39°, very nearly ; dividing this by the annual precession
50.2", gives 2796 years since he, flourished, or about 950 years
before the Christian era. Meton, the famous astronomer of Athens,
says that the star Beta Arietis, was in the vernal equinox in his
time, but at the commencement of the present century its longitude
was 31°, 10', 44", this divided by the annual precession, gives
2236 years from the time of Meton's observations to the commence-
ment of the 19th century, or 436 years before Christ. If we know
the year in which any event occurred, we are frequently enabled
to tell nearly the day on which that event transpired. Thus,
Thucydides tells us that the investment of Platea, during the fifth
year of the Peloponnesian war, which was 426 years before the
Christian era, occurred about the time of the heliacal rising of
Arcturus. But the heliacal rising of Arcturus then occurred in
the month of August, and hence we are enabled to not only give
the year, but nearly the month when this event occurred. And
we may here remark, that the beginning of the Peloponnesian
war, is itself, determined to be 431 years before Christ, by means
of an eclipse of the moon which occurred, as can be most accu-
rately calculated, April 25th. In the same year, on the 3d of
August, an eclipse of the sun was visible at Athens, concerning
which, Thucydides, the celebrated Greek historian, remarks :
that a solar eclipse happened on a summer's day, on the after-
noon, in the first year of the Peloponnesian war, so great that the
stars appeared.

" We are apt to- undervalue the science of the ancients; we
ought rather to look upon it with respect and admiration. It is truly
astonishing that with their imperfect instruments, they arrived at
so much accuracy in their astronomical calculations. The very
want of instruments led to an intensity of observation much
greater than ours. As the savage inhabitant of the forest with-
out a compass, marks his course through the pathless wilds with
an accuracy far beyond that of the civilized man, so at a very
early period of the world's history, did even barbarous nations
learn by the rising and setting of the constellations to regulate the
course of the year. However rude therefore, the Romans under

94 THE WORLD.

Romnlus may have been, it was impossible for them to depart
greatly from the tropical year; because they .watched the constel-
lations, and-connected with their rising and setting the seasons
of agriculture, and the times of their religious festivals. Any
alterations would be quickly perceived and the very observances
of a religion, the gods of which presided over their secular em-
ployments, served as a balance-wheel to regulate the movements
of their chronology."

We shall conclude this chapter with some account of the Zodiacs
discovered by the scientific men who accompanied the French
expedition to Egypt, and which were thought to give an age to
the world much greater than the generally received system of
chronology. We may here remark, that the 'evidence appears
from other sources, to be pretty conclusive, that man has not in-
habited the globe for more than about 6000 years, although the
evidence is equally strong, that the globe itself, is, perhaps,
millions of years old, and has been inhabited by a race of animals,
and covered with a vegetation, entirely unknown at present. During
the campaigns of the French army in Egypt, a Planisphere and
Zodiac were discovered by Mons. V. Denon in the Great Temple
of Dendera, or Tentyra, and copied in his " Voyage, dans la Basse
et la Haute Egyple, pendant les Campagnes du General Bona-
parte." Paris, 1802, Fol. Vol. II. Plates, 130, 131, 132. Den-
dera, anciently the large city of Tentyra, is a town of Upper
Egypt, situated at the edge of a small but fertile plain, about a mile
from the left bank of the Nile, and 242 miles south of Cairo. Its
Temple, magnificent even in ruins, is the first that the Egyptian
traveler discovers on ascending the Nile ; it is 265 feet m length
and 140 feet in breadth, and has 180 windows, through each of
which the sun enters in rotation, and then returns in a retrograde
direction. The front of the Temple is adorned with a beautiful
cornice and frieze, covered with hieroglyphics, over the centfe of
which is the winged globe; while the sides are decorated with
compartments of sacrifices. In the front of the building is a
massive portico, supported by 24 immense columns, in four rows,
having circular shafts covered with hieroglyphics, square capitals
resembling Egyptian Temples supported by four human heads

EGYPTIAN ZOUIACS. 95

horned, and round foliated bases on square plinths. On the ceiling
of this portico is the large Zodiac, partly carved and partly
painted in natural colors, on a blue ground studded with yellow
stars. The general design of the Zodiac is divided in two, and
represents two female figures, which bend over the divisions,
typical of Isis, or the year ; with a winged globe placed against
each, allusive to the sun entering his course. Each band of the
Zodiac is divided into two, by a broad line covered with smaller
hieroglyphics. On the upper division of the Zodiac, which is the
broadest, are represented six of the Zodiacal signs ; and under
them, in the second division of Lhe top band, are 19 boats, each
carrying a figure significative of some astronomical appearance ;
accompanied by an Eg3T>tian inscription in a square. The con-
stellations, and other heavenly bodies, were the Divinities of
Egypt, and it was supposed that they performed their revolutions
in boats. The other great band contains the six remaining signs
of the Zodiac ; and on its lower division are 19 other boats, as
before. The Rev. Samuel Henley, in his very instructive and
highly erudite remarks on this Zodiac, published in the Monthly
and Philosophical Magazines, says, that these boats signify the
nineteen years of the Metonic, or Lunar Cycle, which contains
6940 days ; after which, the New and Full Moons, and other
Aspects, are supposed to return to the same day of the Julian year.
The smaller Zodiac, or rather Planisphere, is carved on the ceiling
of a separate quadrangular apartment on the east side of the Temple.
It is of a circular form, and is supported by four human figures,
standing, and eight kneeling,who have hawks heads. In both these
Zodiacs the equinoctial points are in the constellation Leo, and it
was by some inferred that they were constructed at the time when
the sun entered this constellation at the equinox, or more than 9,700
years ago ; about 4,000 years before the Mosaic record. These
Zodiacs were brought away, and exhibited in the Louvre at Paris ;
and for a long time were the occasion of much discussion. All
the speculations of infidel philosophers were, however, scattered
to the winds by the discoveries of Champollion ; and the disserta-
tions of Visconti and Henley have proved, in opposition to the
infidel arguments of Ripaud, Petau and Archer, that they are of

96 . THE WOKLIX,

the age of Augustus Caesar ; and that they were erected in the
Julian Year 4695, which then regulated the Egyptian , twenty-
four years before the actual birth of our Savior, and twenty-eight
years before the common era. All this is confirmed by the fol-
lowing Greek inscription, over the outer or southern portal of the
Temple : — " On account of the Emperor Csesar, God, the son
of Jupiter, the Deliverer, when Publius Octavius being Governor,
Marcus Claudius Posthumus Commander in Chief, and Tryphon
General, the Deputies of the Metropolis consecrated, in virtue of
the Law, the Propylaeum to Isis, the greatest of Goddesses, and
to the associated Gods on the Sacred Thoth." The Country of
Egypt, had at that time become a Romish Province ; and Augus-
tus Caesar, in the 31st year of his age and the 725th year of Rome,
ordained that the Egyptian Thoth should for ever commence on
the 29th of August.

THE SEASONS. 97

CHAPTER VIII.

The Seasons.

" For this the golden sun the earth divides,
And, wheel'd through twelve bright signs, his chariot guides,
Five zones the heaven surround; the centre glows
With fire unquench'd and suns without repose:
At each extreme, the poles in tempest tost,
Dark with thick showers and unremitting frost:
Between the poles and blazing zone confined,
Lie climes to feeble man by Heaven assigned.
'Mid these the signs their course obliquely run,
And star the figured belt that binds the sun." m

Sotheby's Virgil.

WE have, at length, arrived at that part of our work, which will
treat upon and explain the phenomena of the seasons. All that
we have said in the preceding chapters, has been preparatory to
this, and, we trust, that there will not be less of beauty, or poetry,
in our contemplations of those great changes which mark the
rolling year, because we can understand the causes which produce
them. To our own mind, there is no subject more delightful
than this, of the changing year ; a theme, which is perhaps, still
more endeared to us by the beautiful poetry of a Thompson, a
Bloomfield, and a Cowper. A theme, which, even to Chaucer,
and Spenser, and Shakspeare, and Milton, was a passion.

After the somewhat tedious detail and explanation, which has
preceded", we feel, on approaching this always interesting subject,
as Milton expresses it,

" As one who long in populous cities pent,
Where houses thick and sewers annoy the air,
Forth issuing on a summer morn, to breathe
Among the pleasant villages and farms."

To behold Nature a? she is, and see the glorious changes which
she wears, from the unsullied mantle of winter to the russet garb
pf autumn, we must quit the busy haunts of men, and leaving the

98 THE WORLD.

noisy streets and smoky cities, seek the country fields, and lanes.
We have been much struck with a remark of Howitt, in his
" Book of the Seasons," in which he thus deprecates the necessity
that deprives our childhood of a contemplation of those beautiful
changes which mark the year. *' Oh that I could but touch a
thousand bosoms with that melancholy which often visits mine,
when I behold little children endeavoring to extract amusement
from the very dust, and straws, and pebbles of squalid alleys,
shut out from the free and glorious countenance of Nature, and
think how differently the children of the peasantry are passing the
golden hours of childhood ; wandering with bare heads, and un-
shod feet, perhaps, but singing a 'childish, wordless melody,'
through vernal lanes, or prying into a thousand sylvan, leafy
nooks, by the liquid music of running waters, amidst the fragrant
heath, or oh ibe flowery lap of the meadow, occupied with winged
wonders without end. Oh ! that I could but baptize every heart
with the sympathetic feeling of what the city pent child is con-
demned to lose ; how blank, and poor, and joyless must be the
images which fill its infant bosom* to that of the country one,
whose mind

Will be a mansion for all iovely forms,

His memory be a dwelling-place

For all sweet sounds and harmonies! "

In the absence of a system of chronology to mark the returning
periods of nature, the ancients were obliged to note the aspects of
the stars. We have several times, in the preceding pages, referred
to this, and we may now remark, that some of the most beautiful
passages of the ancient poets, contain allusions to- the stars as
connected with agriculture. Hesiod, the oldest poet of the
Greeks, has given a minute detail of the heliacal rising of the
stars, accompanied with the most pleasing descriptions of the
successive occupations of rural life. The name of the poem is,
"Opera et Dies,'1 the Works and Days. This poem Virgil has imi-
tated, in the first and second "Georgics;" a word compounded
of two Greek words, and meaning, works or labors of the earth,
and corresponding almost exactly with our word agriculture. We
shall give occasional quotations from both these poems, in our
present chapter.

SIGNS OF THE ZODIAC. 99

In the absence of a correct calendar, such as our almanacs now
furnish, the early cultivators of the soil very wisely determined
the recurrence of various seasons, by the aspect of the heavens.
It was, to them, a matter of no small importance, to know, with
unerring certainty, the time when first to break the soil, and plant.
This they could not do, judging from the simple change in the
climate, or temperature, due to the return of spring ; as various
causes, which we need not mention, render this indication liable
to great uncertainty. Hence, at a very early day, the apparent
path of the sun, in the heavens, was divided into twelve portions,
called signs ; and as these signs were mostly representatives of
living objects, it was called the - Zodiac, from a Greek word
meaning life. In a previous chapter, we have shown how this
division was accomplished by means of the water-clock. The
present division of the Zodiac was probably made by the Egyptians,
and they named the signs with particular reference to agriculture,
and the seasons at the time of their invention. From the
Egyptians it was undoubtedly borrowed by the Greeks, and from
them has been transmitted to us. As we have elsewhere shown,
these signs are reckoned from the point of vernal equinox, or first
point of Aries, eastward, completely around the ecliptic. Their
names are, Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra,
Scorpio, Sagittarius, Capricornus, Aquarius, Pisces. The sun
enters Aries, or the Ram, at the time of vernal equinox ; hence
this sign was represented under the form of a ram, to which
the character <p was placed, designed no doubt, at first, to repre-
sent a ram's horns. This was the beginning of spring. The
sun entered the next sign, Taurus, a Bull, a month afterwards ;
which was, therefore, appropriately represented by a bull, the
attention now being drawn to plowing and sowing. This sign
was once situated in the constellation Taurus, which numbers
among its stars the beautiful group called the Pleiades, or seven
stars, although now, on account of the precession of the equinoxes,
it is in the constellation Aries. Hesiod alludes to the heliacal
rising and cosmical setting of the seven stars :

"When, Atlas born, the Pleiad stafls arise,
Before the sun, above the dawning skies,
'Tis time to reap ; and when they sink below
The morn illumined west, 'tis time to sow."

100 THE WORLD,

And we find in Job an allusion to the Pleiades, as harbingers
of spring : " Canst thou bind the swee( influences of the
Pleiades," &c. [Job 38 : 31]. The symbol of Taurus is tf , once
intended for a bull's head and horns. The sign Gemini, or the
Twins, which the sun enters two months after the commence-
ment of spring, was denoted by the symbol n» intended to
represent the twin sons of Leda ; as this was the month when the
flocks brought forth, this sign was adopted as the harbinger of a
fruitful increase. The 'next sign is .Cancer, the Crab, the sun
enters this sign at the time of the summer solstice, or at mid-
summer. Previous to entering this sign, it had been rising, each
day, higher and higher, until now, having reached its highest
point, it begins to return ; hence the sign, a crab, an animal
fabled to run backwards as well as forwards, and its symbol g^, is
intended to illustrate this. In the Zodiacs discovered at Dendera
and^Esne, alluded to in the last chapter, the place of this sign is,
occupied by a Scarabeus, or Beetle ; but in the Hindoo Zodiac,
which was probably borrowed from the Chaldeans, and is therefore
older than the Egyptian, we find the figure of a crab. It will be
understood that these divisions of the ecliptic, which heretofore
we have marked as hours, see the figure, page 91, are the com-
mencement and middle of the twelve signs, each sign compre-
hending two hours, 0 corresponding to the first point of Aries, II
the first point of Taurus, &c. It will be noticed that the sun
reaches the highest point of his orbit at VI, or the first point of
Cancer, where the solstitial colure intersects the ecliptic.

The fifth sign is Leo, the Lion. The sun entered this sign
about the time of the overflowing of the Nile, at which period, the
lions, driven from the interior by the heat, hunted along its banks.
This sign is figured in the Egyptian and Indian Zodiacs
very near as we have it now. The symbol is ^, probably a
corruption of an hieroglyphical character, intended for a crouching
lion. The next month, the sun entered Virgo, the virgin. This
was the harvest month, and hence was appropriately represented
by a virgin with a sheaf of wheat. The Egyptians represented
it under the figure of Isis; the symbol is 1TJ7.. This is probably an
hieroglyphical character. The next sign is Libra, the balance,

ZODIAC. 101

represented by a scale-beam =£= . The sun enters this sign at the
time of the autumnal equinox, when the days and nights become
nearly equal all over the world, as we shall soon explain. Virgil
alludes to this constellation :

" When poising Libra rest and labor weighs,
And parts with equal balance nights and days,
Goad, goad the steer, the barley seed enclose,
Till winter binds the ground in dead repose."

The next month, abounding with venemous reptiles, was
characterized by the sign Scorpio, a scorpion, though in some of
the old Zodiacs it is represented under the form of a snake, or an
alligator; its symbol is 1\\. The next sign is represented, in all
the Zodiacs, under the form of a hunter, or archer, as the sun
enters this sign in November, the hunting month, and its symbol
is an arrow f. When the sun enters the next sign, about the
latter part of December, it is mid-winter, and the time of -the
winter solstice, the sun being at the position marked XVIII, see
the figure, page "91. It is represented under the form of a goat,
for now the sun, having reached its lowest southern declination,
begins to climb up in the heavens, like the goat climbing the
mountain steeps ; the sv mbol is ]£?. The next sign is represented
by Aquarius, the water-pourer, perhaps in allusion to the rainy
season, and the symbol,CCO/, is intended, no doubt, to represent the
water, or waves. The last sign is Pisces, the fishes, represented
by the symbol )•£, and the constellation is usually figured in the
heavens as two fishes tied by their tails, for the earth being now
bound in winter's icy chains, subsistence is derived from the
streams.

Such are the t\\ elve signs of the Zodiac, and through one of
these the sun passes eaih month, and thus their names, become
to us, indicative of months, Aries corresponding with March,
Taurus with April, &c. When the sun enters one sign the earth
enters the opposite, as in the following diagram.

Thus, when the earth enters the sign Libra at C, at the time of
the vernal equinox, the sun, S, appears to enter the opposite sign.
Aries, at A, and when the earth arriving at D, enters the sign
Capricornus, at the time of the summer solstice, the sun enters

102 THK WORLD.

t he opposite sign, Cancer, at B. Hence, whatever sign the sun

may be in, the opposite sign will rise at sunset, being 180°, or
half a circle, distant from the sun. If the orbit of the earth was
a true circle, the progress of the sun through the signs would be
performed with an equable motion ; but this is not the ca.se, as we
have shown when speaking of the equation of time. Its orbit is
elliptical, and its major axis lies in the direction of a line joining
the beginning of August and January, nearly, so that the sun is
actually nearer the earth in January than in August. We shall
see, presently, why its rays, at that time, have less effect in
warming the earth, in our northern climates than in summer.
On account of the proximity of the earth, to the sun, in winter,
and its consequent swifter motion ; the sun will appear to move
through the winter signs faster than through the summer signs,
and will therefore accomplish the six winter signs quicker than
the six summer signs. Hence, the winter is always, in any latitude
north of the equator, shorter than the summer. This difference
amounts, in the temperate zones, to almost eight days. At all
places south of the equator it is summer, when it is winter in the
northern hemisphere, as we shall now proceed to show, and
hence the summer there is shorter than the winter, for the sun is

LINE OF APSIDKS. 103

nearest those places in summer. And those signs, which are
winter signs to us, who live in the northern hemisphere, are
summer signs to the inhabitants of the southern. All varieties of
seasons are thus, at all times, upon our globe. When one portion
is covered with the white mantle of winter, another is producing
beautiful flowers. At one place spring is commencing, at another
the autumn, and around the equatorial regions of the earth per-
petual summer reigns. Perhaps there is nothing that seems more
strange to the traveler, than this variety of seasons from change
of latitude. The names of the winter months, which so long
have been associated with ideas of cold, and frost, and storm, seem
strangely misplaced, when he beholds flowers blooming around
him in December, and hears the songs of birds wafted on the
light breeze. Christmas and New Years, which in our northern
country, are wont to be associated with the cheerful blaze, the
merry sleigh-ride, or the drifting snow, bring no such associations
to the inhabitant of the southern hemisphere ; there, mid-summer
reigns, and the cool breezes, which blow over the Indian seas,
laden with perfume, dispel the sultry heat. The cause by which
all this variety is produced, is not the less interesting because it is
simple, and because we see in it a guaranty that long as time shall
last, or the present race inhabit the globe, so long the seed-
time and harvest must return with undeviating certainty.

We have mentioned formerly that the earth's orbit is an ellipse,
and that the longer or major axis of the ellipse is called the line
of the apsides. We might have shown that between the limits of
an ellipse, viz: a perfect circle on the one hand and a straight
line on the other, this orbit might vary, but still the periodic
time of a revolution remain unchanged. But these are theoreti-
cal investigations upon which we cannot enter. We will, how-
ever, observe that the line of the apsides, or major axis of the
earth's orbit, is its most important element, for when this is de-
termined the periodic time of a revolution, and the mean distance
from the sun are also determined. The orbit itself, under the
influence of various forces, may change its ellipticity, expanding
towards a circle on the one hand, or diminishing towards a
straight line on the other, or the ellipse may swing round upon

104 THE WORLD.

this line, altering its position in space; but amidst all these
changes, the line of the apsides knows no change. Its length
remains the same notwithstanding all the perturbations of the
planets%and all the changes to which the rest of the orbit may be
subjected. The eccentricity of the earth's orbit is now slowly
changing, diminishing at the rate of about 11" in a century, on
account of the mutual gravitation of the planets. It will continue
to diminish for centuries, and it is somewhat curious that this
dimunition is indicated by the movements of the moon, for it
produces, as we have remarked before, no effect upon the period-
ic time of a revolution of the earth. It is now pretty well deter-
mined that the motion of the moon is continually accelerated.
Upon comparing observations made at distant intervals, it is found
that the Chaldean and Alexandrian observations give a longer
period, than the Alexandrian and Arabian of the eighth century;
and a comparison of the Arabian and modern observations, gives a
still shorter period. These variations are all periodical, and are
compensated in opposite points of every period, the mean distan-
ces, and mean periods, will always remain the same. "Cold,
we think, must be the heart that is not affected by this mark of
beneficent wisdom in the contriver of the magnificent fabric."

INCLINATION OF THE EARTH'S AXIS. 105

CHAPTER IX.

The Seasons.

"These, as they change, Almighty Father, these
Are but the varied God. The rolling year '
Is full of thee. " Thompson.

THROUGHOUT the preceding chapter, we have spoken of the
plane of the orbit of the earth as inclined to the plane of the equa-
tor. As a necessary result of this, the axis of the earth points, at
all times, towards the same point of the heavens, with the ex-
ception of the slight motion caused by the precession of the
equinoxes. This is a fact, with which we are all familiar, for we
know the pole star is the star towards which the axis of the earth
points throughout the year. Thus, in the following diagram, let

A B C D, represent the earth in four different positions in its
orbit. Now, if the axis of the earth was perpendicular to the plane
of the orbit, as shown in the diagram, then the plane of the equa-
tor, a, I, would correspond with the plane of the orbit, but, as the
plane of the equator manifestly does not correspond with the plane
of the ecliptic, the axis of the earth must be inclined to the plane
'of its orbit, as in the next diagram, and this inclination it main-
tains throughout its entire revolution around the sun, its axis
always pointing towards the polar star. Of course, in our diagram,
this does not appear to be strictly the case, as we cannot repre-
sent the star removed to a sufficient distance. The inclination of
the axis of the earth to the plane of the sun's apparent path, is the
cause of all the variety of the seasons ; of the differing lengths
of the nights and days ; and the daily changes of the sun's decli-
nation. If the earth's axis had been placed perpendicular to the

106 THE WORLD.

plane of the ecliptic, -then, at all seasons of the year, the days and

*

nights would have been equal all over the world, for, as will be
seen on reference to the figure on page 105, the sun would shine
from pole to pole, and as it would illuminate but half the globe at
once, a spectator any where on its surface, would be just as long
in passing through the unilluminated as the illuminated portion.

Thus, a spectator at A, on the parallel of latitude B C, would be
just as long in moving through the hajf of the unilluminated por-
tion of the earth B A, -as through half the illuminated A C. This
is the case at the equinoxes. When the sun is in either of those
points of his orbit which crosses the equator, then it illuminates
the globe from pole to pole, i. c. when he is in either of the points
0, or XII, see the figure on page 91. We have already shown
that the apparent diurnal path of the sun through the heavens due
to a rotation of the earth upon its axis, is in what is called a diurnal

DECLINATION 01 THE SUN. 107

circle, or a circle parallel to the equator ; hence, at the time of
the equinoxes, the sun will, apparently, in his diurnal circle in
the heavens, move in the equator ; and as the successive meridians
come under, it will appear directly over head, or vertical, at noon,
to a person any where on the equator. As the globe turns around,
the sun now passes directly over the islands of Sumatra and
Borneo, and the islands in the midst of the Pacific ocean ; also
over the northern part of South America, the middle of Africa,
and the Indian ocean. We will suppose it is the time of the au-
tumnal equinox, when the sun enters Libra, or is in the position
marked XII, in the figure on page 91. A month after, the sun
has moved to the position XIV. And as the earth turns around
on its axis, it appears no longer vertical, or over head, at the
equator, at noon, but to those places situated on the parallel c J\
*over the islands of New Guinea and Java; the middle of South
Africa ; the top of the Brazils ; and, perhaps, the Society, and
the Friendly islands. As the sun moves still farther on in its
orbit, to the position VI, it appears now vertical, or over head, at
noon, to an observer on the parallel g h, and as this is the greatest
distance from the equator, and therefore farthest south where it
can be vertical, at noon, and, as after this, it again approaches
the equator, this point is called the solstitial point, i. e. the point
where, having reached its greatest southern declination, the sun,
apparently, for a few days, remains still, or at precisely the same
altitude at noon, for a few days, and then begins to return ; this
limiting parallel on the earth is called the tropic of Capricorn, for
it is now January, the time of the winter solstice, when the sun
enters the sign Capricorn. The earth is now illuminated by the

sun, as shown irt this diagram. The sun being vertical at noon,

108 THE WORLD.

to all places on the parallel C D, it will be observed that it is now
summer in the southern hemisphere, and that there, the days are
now longer than the nights, the illuminated portion C G-, being
greater than the shaded portion G D. At the equator, however,
the days and nights are still equal, but in the northern hemis-
phere it is mid-winter, and the days are shorter than the nights,
as the arc E H, is shorter than the arc H F, the former represent-
ing half the day, the latter half the night. Here, then, is the
explanation of the short days in winter, and the long nights, and
it will also be seen that, to an observer any where in the northern
hemisphere, the sun will come to the meridian very low down .
It will also be noticed, that the shadow of the unilluminated por-
tion of the earth, falls entirely beyond, or without the antarctic
circle I K, and includes the arctic circle L M. To an observer,
therefore, within the southern polar circle, the sun now never
sets. Three months before, when the earth and sun were in the
positions shown in the figure, page 106, the sun rose a short way
above the horizon, within each circle, but each succeeding day
he sank lower and lower, to those within the arctic or northern
polar circle, and rose higher and higher to those within the an-
tarctic circle, so that now, begins the long day of the latter, and
the long night of the former. It would be a curious sight to an
inhabitant of the more temperate zones, to see the sun thus
gradually mounting above the horizon, moving completely around
without setting, and visible during the whole day, for nearly six
months. Although darkness reigns at the other pole, so far as
the direct rays of the sun are concerned, yet the long night is en-
livened by the bright moon light, which reflected from a thousand
hills of snow, sheds a bright light around, and the planets and
stars in that cold region, where no mists ever obscure the sky,
twinkle in the clear firmament like diamonds. The bright cor-
ruscations of the Aurora, with changing and fanciful lights, are
there seen in their greatest perfection, and cheer, with their
varying forms, the hunters who penetrate within the icy circle ;
and here nature is seen in some of her grandest forms. Huge
mountains of ice, formed by the winters of centuries, rear their
Alpine summits to the sky, and life in singular forms, sport on its

THE SEASONS. 109

cold surface, or beneath the colder waves. The Polar Bear, and
the huge Walrus, and the Seal, sport among the floating fields of
ice; and the great Auk, or Penguin, seems to choose, by instinct,
this desolate and almost forsaken region of the earth,

As the earth moves on in its orbit, the sun now rises higher
and higher in the heavens, at noon, each day, and finally arrives
at the point of vernal equinox and enters the constellation Pisces.
Again the nights and days are equal all over the globe, the earth
being illuminated from pole to pole. As the sun proceeds still far-
ther north of the equator, the north pole becomes more and more
illuminated, until finally it arrives at the point of greatest differ-
ence between the equator and ecliptic marked XVIII, see figure on
page 91, which is the point of the summer solstice. The sun is
now vertical in the northern hemisphere, at noon, at all places
situated on the parallel a bt which is called the tropic of Cancer. As
the sun is now entering the sign Cancer, and since the north pole

of the earth is now wholly illuminated, as in the above diagram,
it is evident that the north pole, or rather the axis of the earthy is
inclined towards the sign Cancer. The days are still equal to the
nights, at the equator, but at all places north of the equator, as for
example on the parallel A B, the days are now longer than the
nights, the half illuminated portion I B. being greater than the
half unilluminated A I. It is now mid-summer, the beginning
of July, in the northern hemisphere, while at the same time it is
mid-winter in the southern. The arctic circle is now wholly illu-
minated, but the antarctic is in complete shade. At this season
the sun mounts highest in the heavens to all north of the equator,
and lowest to all south of it. The rays of the sun falling almost
direct, or perpendicular, upon the earth* in our northern latitude

110 THE WORLD.

in summer, and also the days being long-er than the nights, and
the earth being thus warmed during the day more than it is cooled
during the night, this excess of warmth contributes to augment
the summer heat. It will also now appear why, although
the earth is actually nearer the sun in winter than in the
summer, no increase of heat is, on this account, perceived, as the
rays, at this time, fall very slanting upon the earth in the northern
hemisphere, although in the southern hemisphere, the summer
occurring at the time when the sun is nearest the earth, is much
warmer than the same season at the north. The lines we have
thus seen, apparently marked on the earth by the sun, divide the
earth into five zones, or belts. The north frigid; the north tem-
perate; the tropical, or torrid; the south temperate ; and the south

frigid. The first and last are included within the polar circles,
and are always cold, inhospitable regions. The temperate /ones
are included within the polar circles and the tropics, whilst the
tropical, or equatorial regions lie wholly within the two tropics.
At the equator, as we have already intimated, and indeed for
some distance north and south, nearly to the tropics, perpetual
summer reigns, as the sun is, at almost all times vertical at noon;
at the equinoxes, it is truly so; but at the time of the summer
solstice, it is seen by the inhabitants of the equatorial regions
passing between the zenith and the northern horizon, not, how-
ever, nearer the north pole, or the polar star, than the rest of the
world perceive it ; for to them, the north star is on the horizon.
At the time of the winter solstice, it is seen by a spectator at the

CHANGE OF THE LINE OF APSIDES. Ill

equator, to pass between the zenith and the southern horizon,
about as far from being1 vertical at noon there, as it is to us at
the time of summer solstice. ' Hence, an observer there, looking
directly overhead, might imagine the equator a line marked in
the heavens extending from east to west, like the line E W; Z

being the zenith, or point directly overhead, and A B the sun's
path, along which it would appear to move; being at Z, at the
time of the equinoxes, rising directly east and setting directly west,
and at B at the time of the slimmer solstice, describing, by the
diurnal motion of the earth, the tropic Cancer, and at A at the
time of winter solstice, its diurnal path being the tropic of
Capricorn.

We have thus, at some length, explained the phenomena of the
seasons, and will now, for a few moments, consider what will be
the effect of the precession of the equinoxes. The earth's axis,
at present, is inclined towards the sign Cancer, which is located
in the constellation- Gemini. In the course of about 6000 years,
it will still be inclined towards the sign Cancer, but that sign will
be in the constellation Pisces. And in 6000 years more, towards
the constellation Sagittarius. In consequence of this change,
the seasons will all, really, be misplaced about six months, although
the various contrivances for retaining the names of the months,
as indicative of the several seasons, will doubtless, then, as now,
make the 21st of March the commencement of spring, or time
of vernal equinox. There is, however, a more important change
than this, which will affect our seasons The major axis of the
earth, or line a b, see figure on page 78, has not a fixed direction
in space, but is slowly moving from west to east, i. e. in the order
of the signs, at such a rate that it will require about 100,000 years
to make a complete revolution. The earth arrives at its perihelion

112 THE WORLD.

now about the 1st of January, but 50,000 years hence, it will be
in its perihelion in July, or time of mid-summer in the northern
hemisphere, and at that time the* earth's axis will be inclined
nearly as at present, unless changed by some great convulsion^-
The effect of this change of the direction of the line of apsides
will be therefore, to cause the earth to arrive at its perihelion at
the time of mid-summer in the northern hemisphere, instead of
at mid-winter as at present, thus producing, if the relative distri-
bution of land and water remains unchanged, a tropical climate
or nearly so, over the whole globe. .

Such periods of time are however, too remote to be worth much
notice from us, except for their interest in a geological point of
view, for we believe this to be the true explanation of the greater
warmth of the climate of the ancient world, as indicated by fossil
flora and fauna ; we shall refer to this again.

We have given no explanation of the cause of the precession
of the equinoxes, or the motion of the apsides. It would be
extremely difficult for us to do so in a manner intelligible to the
general reader. The facts, however, are unquestionable. The
former is caused by the attractions of the sun and moon upon the
excess of matter at the equator, for the earth is not truly spherical,
but oblate, on account of its diurnal rotation. This equatorial
belt, not corresponding with the plane of the ecliptic, is acted upon
obliquely, and with varying force by the sun and moon, producing
the retrogradation of the nodes. The motion of the apsides is the
conjoint effect of the attractions of the planets upon the earth in
the various parts of its orbit.

We here close the first part of our volume, not however, with-
out the hope that we have succeeded in making it interesting,
and that the reader will feel repaid for the time spent in peru-
sing it.

THE WORLD.

PART II.

METEOROLOGY.

CHAPTER I.

Meteorology.

*' 'Tis pleasant, by the cheerful hearth, to hear
Of tempests, and the dangers of the deep,
And pause at times, and feel that we are safe';
Then listen to the perilous tale again,
And with an eager and suspended soul,
Woo terror to delight us." Southey.

WE now enter upon that part of oursuhject which treats of the
atmosphere, the waters of the globe, and the mountain rocks of
which it is composed- No department of natural history abounds
more in important facts and interesting conclusions. We com-
mence first with " METEOROLOGY."

The science of meteorology describes and explains the various
phenomena which occur in the region of our atmosphere. The
word is of Greek origin and means aloft or elevated. Itis a study
which has deeply engaged the attention of men in every stage
of society, from the roving savage to the refined votary of wealth
and pleasure. The moment we cross our thresholds we commit
ourselves to the influence of the weather ;-*but the hardier class
of the community, the shepherd, the plowman, and the mariner,
whose labor creates or procures the staple articles of life, are al-
ways exposed by their occupation to the mercy of the elements.
They are hence led by the strongest motives, to examine closely

116 THE WORLD.

the varying appearance of the sky, and to distinguish certain mi-
nute alterations which usually precede the more important chan-
ges. Thus Virgil in one of the most beautiful passages of the
Georgics gives for the use of the mariner and husbandman, the
warnings which in his time were thought to precede approaching
storms of wind, which he observes, well contemplating, the care-
ful husbandman will gather his herds into their stalls; they are
eleven in number. I. The agitation of the sea, the swelling
waves rolling upon the shore. II. Noise from the mountains of
the rustling leaves and crackling branches. III. The roaring
of the surf as it breaks upon the shore. IV. The murmuring of
the groves. V. The flight of sea-birds and their screams. VL
Their playing or sporting on the shore. VII. The herons forsa-
king their accustomed marshes and mounting aloft. VIII. The
fall of meteors, portending winds, and which is thus similarly al-
luded to by Milton :

" Swift as a shooting star,

In Autumn thwarts the night, when vapors fired
Impress the air; and show the mariner
From what point of his compass to beware
Impetuous winds."

IX. Nocturnal streams of light, probably the Aurora. X. Straws
rising and floating in the air. XL The play of floating feathers
driven about upon the surface of the pool. Next he gives twelve
prognostics of rain, which were thought so conclusive in their
indications that he observes "Never hath a shower hurt any per-
son unforewarned," viz: thunder from the north; the clash of east
and west winds, and the flight of the cranes into the vallies to
avoid the impending tempests. Heifers snuffing the \vind; the
circling flight of swallows round the water, and skimming over
its surface. The croaking of the frogs; ants busy with their eggs.
The rainbow, which was then supposed to have drank the water
that supplied the clouds. The hoarse murmur of the flocks of
crows. The diving of sea birds and of swans; smoothing and
oiling their plumage. A solitary bird pacing the sand; and lastly
the gathering of fungous excrescence on the wick of the lamp,
causing the oil to sputter and the flame to emit sparks. Prognos-
tics of the coming weather drawn from the appearance of the

INDICATIONS OP THE WEATHER. 117

moon or sun, are also given. I. From the moon; darkened when
new, she betokens rain. If red, wind; if serene in the fourth
night she promises fair weather for that month. II. From the
sun; if in rising, spotted, or showing only the centre of his orb,
rain is portended. If of a bluish color in setting, rain, if red,
wind. If spotted at setting, rain and wind; and if bright at ris-
ing and setting, clear weather with a northerly wind.

After these beautiful descriptions, which bring the poem home
to every one, follow nine indications of fair weather. The bright-
nes of the stars, and of the rising moon. The unclouded sky,
and kingfishers not expanding their wings to the sun; sows no
longer tossing wisps of straws into the air. The clouds floating
low; the silence of the owl at sunset, whose hooting was once
supposed to forebode rain. The falcon soaring after the lark, and
the crows social, and cawing with clear notes. Many of these
signs are even now considered as harbingers of the coming change
of weather, and more particularly the formation and arrangement
of certain clouds, to which we shall again allude. No doubt the
early observers of the weather often mistook the indications of
those aspects we have mentioned, and inferred conclusions from
mere casual circumstances.

The signs which usually precede the coming tempest are thus
beautifully given by Thomson. — .(Winter, 1. 118, ei seq.)

" When from the pallid sky the sun descends,
With many a spot, that o'er his glaring orb
Uncertain wanders, stain'd — red fiery streaks
Begin to flush around. The reeling clouds
Stagger with dizzy poise, as doubting yet
Which master to obey ; while rising slow,
Blank, in the leaden-colored east, the moon .
Wears a wan circle round her blunted horns.
Seen through the turbid, fluctuating air
The stars obtuse emit a shivering ray ;
Or frequent seem to shoot athwart the gloom,
And long behind them trail the whitening blaze.
Snatch'd in short eddies, plays the wither'd leaf;
And on the flood the dancing feather floats.
With broaden'd nostrils to the sky upturn'd
The conscious heifer snuffs the stormy gale.
Even as the matron, at her nightly task,

118 THE WORLD.

With pensive labor draws the flaxen thread,
The wasted taper and the crackling flame
Foretell the blast. But chief the plumy race,
The tenants of the sky, its changes speak.
Retiring from the downs, where all daylong
They pick'd their scanty fare, a blackening train
Of clamorous rooks thick-urge their weary flight,
And seek the closing shelter of the grove.
Assiduous, in his bower, the wailing owl
Plies his sad song. The cormorant on high
Wheels from the deep, and screams along the land.
Loud shrieks the soaring hern ; and with wild wing

The circling sea-fowl cleave the flaky clouds.

Ocean, unequal press'd, with broken tide

And blind commotion heaves ; while from the shore,

Eat into cftverns by the restless wave,

And forest-rustling mountain, comes a voice,

That solemn-sounding bids the world prepare.

Then issues forth the storm with sudden burst,

And hurls the whole precipitated air

Down in a torrent."

Those tokens which portend the more violent convulsions of
the atmosphere, the pelting storm, or the careering tempest, are
generally of a decided character, but the symptoms which go
before the ordinary fluctuations of the weather can only be dimly
conjectured by long experience and sagacious observation.

Nothing can be more utterly groundless than the disposition to
refer the ordinary changes of the weather to the influence of the
moon. But, compared with this, the fancied efficacy of the stel-
lar aspects vanishes into the shadow of a vision. The moon by

% BAROMF.TKR. 1 19

its attraction does raise a small tidal wave in the atmosphere,
which is indicated by the barometer, but its effect is scarcely per-
ceptible. According to the calculations of Laplace, the joint ac-
tion of the sun and moon is only capable of producing a tropical
wind flowing westward at the rate of about four miles a day, and
the effect produced by the conjoint actions of Jupiter and Venus,
when nearest the earth, would be a very gentle breeze moving
about a foot in fourteen or fifteen days, or about a mile in twenty
years.

The invisible and perfectly elastic fluid which surrounds the
earth is called the atmosphere, or atmospheric air. It appears to
consist principally of two distinct expansible fluids, mechanically
combined in different proportions, a single portion or atom of oxy-
gen gas being united to three parts by weight, or four by bulk of
nitrogen, with a very slight admixture of carbonic acid, perhaps
one-thousandth part of the whole. Air was formerly considered
as an elementary body, but the analysis of this rare medium is
one of the finest discoveries of chemistry. The atmosphere, al-
though apparently so rare and mobile, is nevertheless, capable of
presenting great resistance to any obstacles to which it may be
opposed. We shall see this more completely illustrated when we
describe the phenomena attending hurricanes and other windy
storms, but meanwhile it will answer our present purpose to simply
refer to its use as a natural agent in propelling vessels by means
of sails, and urging the sails of wind mills. Although it is, com-
paratively speaking, light, and in the ordinary acceptation with-
out weight, yet we must not forget that it is now clearly demon-
stratable that the atmosphere which invests our earth, presses
everywhere on its surface with a power of about 15 Ibs. to the
square inch. The famous Torricellian experiment proves this.
It is well known that if the mouth is applied at one end of a small
tube, the other end of which is immersed in water, that upon ex-
hausting the air from the tube by the process called suction,
the fluid rises swiftly and flows into the mouth; this is a philo-
sophical experiment, but well known to every child. Now, if a
person ignorant of the principle that caused the water to rise in
the tube, should be asked for an explanation, he might answer

120 THE WORLD. «

as Galileo did, that it was " Nature's abhorrence of a va-
cuum." It is however, effected by the pressure of the atmosphere.
When an open tube is dipped at one eud into the water, the li-
quid does not rise in the tube until the air within it is ramored by
exhaustion, as we have described, when immediately the fluid
rises, because the atmosphere without the tube, pressing upon the
mobile particles of the fluid, forces them up. Now it is evident
that if the tube was long enough, and the exhaustion perfect, the
pressure of the air upon the liquid outside would raise a column
of water just so high that the weight of this elevated water would
be equal to the pressure of the atmosphere upon the liquid at the
bore or orifice of the tube. The column of water which can be
thus raised or sustained, is generally about 33 feet high; and as
such a column when its area is one square inch, weighs about 15
pounds, we infer that the atmosphere presses upon the earth with
a force of about 15 pounds to the square inch. Mercury or quick-
silver, being 14 times heavier than water, the atmosphere will
support a column of this but about 29 or 30 inches in height; and
when a tube a little more than 30 inches long is closed at one end,
and filled with mercury, and then inverted into a basin also con-
taining mercury, the column will remain suspended nearly thirty
inches high. The mercurial column would continually remain at
the same elevation, if the atmosphere was subject to no variations;
but this is not the case; upon observation it is found subject to
continual variation, almost always falling before a wind arises,
and preceding rain, and again rising at the approach of calm
and fair weather. The instrument thus becomes a laromelcr, or
measurer of of the weight of the air. It is an invaluable instru-
ment on ship-board, giving indications of the coming tempest
long before any change is detected in the appearance of the sky.
Since the barometric column is wholly supported by the press-
ure of the atmosphere, communicated through the mobile parti-
cles of the fluid metal, to the open mouth of the tube, it obvious-
ly points out a method of determining heights. This however, is
from several causes, a matter of some nicety ; thus the density
of the air decreases as we rise upward, owing to the extreme
elasticity of air. It is well known that a piston may be thrust

DENSITY OF THE AIR. 121

down a tube closed at one end, condensing the air before it, until
it can absolutely be urged no farther, the included air resisting its
descent as effectually as any metal ; upon releasing the pressure
it again expands to its original bulk. The stratum of atmosphere
in immediate contact with the earth is subject to the entire press-
ure of the superincumbent mass, and is thus denser, i. e. has
more atoms contained in the same space than the stratum imme-
diately above, and the second stratum is denser than the third,
and so on. This decrease of density gives a limit to the extent of
the atmosphere.

The ancients imagined that our atmosphere reached at least as
far as the moon, but the discovery of the weight and pressure of
the air destroyed at once this magnificent vision. Comparing
the length of the mercurial column with the density of the aerial
medium, it follows that if the atmosphere is a uniform fluid, it
cannot exceed the elevation of five miles. But the air being
very dilatable, the higher portions sustaining as we have shown
a diminished pressure, must swell upwards and occupy a propor-
tionally greater space. This property removes the boundary of the
atmosphere to a much greater elevation. A height of 42 miles
would indicate a rarefaction of a thousand times, for it has been
proved that the density decreases in a geometrical ratio, as the
height increases in an arithmetical ratio, thus :

The elevation being in miles, |U|3|6|9| 12 j 15 |&c.

[he density will be |l|||i|&|l-Hi|l-32|&c.

The famous Kepler first proposed a method of determining the
height of the atmosphere by means of the twilight. After sunset
there appears in the western sky a bright illumination called twi-
light, which is caused by the sun's rays shining upon the higher,
regions of the air. This twilight fades when the sun has sunk
below the horizon a certain distance ; thus, let C be the position
of a spectator upon the earth, encompassed with its atmosphere,
and SAB the lowest ray of the sun after sunset, B C being the
horizon. The sun's rays would now illluminate the portion of
atmosphere between A and B, producing twilight visible to a spec-
tator at D, but not tp one at C. Now the twilight, or this last ray

122 THE WORLD.

of twilight, SAB, expires whenever the arc DC, is equal to 9°,

or one-fortieth of the whole circle. The angle B C O is evident-
ly a right angle, or 90°, consequently, from the well known prin-
ciple that-the square of the longest side of any right angled tri-
angle, as B O C, is equal to the sum of the squares of the other
two sides; the square of B O, is equal to the square of O C, ad-
ded to the square of B C. Now B O is the height of the atmos-
phere, added to the half diameter of the earth, and O C is also
the semi-diameter of the earth, or 4000 miles nearly, whilst B C,
which may be assumed equal to D C, is the one-fortieth of the
circumference of the earth, or 600 miles nearly. Hence the square
of B O is equal to 6002, plus 4000*, which is 16,360,000, and the
square root of this is 4045, which is the length of B O; subtracting
D O, or 4000 miles, leaves 45 miles for B D, the height of the
atmosphere. It is probable the atmosphere extends beyond this,
as, unless the sky be overcast, there is total darkness in no climate,
even at midnight, and therefore the atmosphere must extend to
such a distance as to receive the most dilute glimmer after the
sun has attained his greatest obliquity, and sunk 90° below the
horizon ; this would require ,an elevation of at least 1640 miles,
and before the centrifugal force would balance the attraction of
gravitation, it is possible it might extend 22,000 miles, and yet,
this is scarcely a twentieth part of the distance of the moon. If
the atmosphere really spreads out, even to the first mentioned
limit, it must, in its remote verge, attain a degree of tenuity which
. it would baffle the imagination to conceive.

It was soon conceived, after the discovery of the pressure of
the air, that the height of the mercurial column would vary with

PRESSURE OF THE AIR. 123

* f

the elevation at which it was observed. The experiment was
tried by M. Perier, at the suggestion of his brother-in-law the
celebrated Pascal, who himself living at Paris, was not so con-
veniently situated as M. Perier, who lived at Clermont, in Au-
vergne, in the immediate vicinity of several mountains, which
modern geology proves to have once been active volcanoes. Early
in the morning of the 19th of September 1648, (two hundred
years ago) Perier with a few friends, assembled in the garden of
a Monastery situated near the lowest part of the city of Clermont,
where he had brought a quantity of mercury, and two glass tubes
closely sealed at the top. He filled and watched them as usual,
and found the mercury to stand in both tubes at the same height,
namely 28 English inches; leaving one behind in the custody of
the sub-prior, he proceeded with the other to the summit of the
mountain, the Puy de Dome, and repeated the experiment. Here
the party were delighted, perhaps we may say surprised, although
they expected it, to see the mercury sink more than three inches
under the former mark, and remain suspended at a height of
only 24.7 inches. In his descent from the mountain he ob-
served at two several stations, that the mercury successively rose,
and returning to the monastery it stood at exactly the savoe point
as at first, thus incontrovertably proving that it was the pressure
of the atmosphere which balanced the suspended column.

We will close this chapter with a description of a barometer or
baroscope, which any one who has access to a tin-shop can

construct, it is an instrument of great delicacy in its indications.
Let A B C D, be a vessel partly filled with water, in which the

124 THE WORLD.

»

hollow air-tight body a b c d is floating, having a tube, ef, opening
into the interior. When placed into the water it is evident that
a certain portion of the liquid will rise in the tube, and if light
weights are added either below or above, the whole body may be
caused to sink until its top is even with the surface of the fluid ;
ag is likewise a tube, which containing air, will prevent the in-
strument in great changes of weather from sinking to the bottom,
b h, is a wire, and g h and i b are threads stretched obliquely from
the tube to the wise. As the instrument rises and falls, a little
bubble of air on the thread shows the motion; the threads are so
located that when the bubble reaches i on the lower, it commences
at h on the upper one. A change of the pressure of the atmos-
phere preceding a wind or rain, by reason of a diminished press-
ure upon the surface of the water in the vessel, A B C D, forces
less of the fluid into the tube ef, and thus the specific gravity of
the included air being lessened by its expansion, the instrument
rises, and the bubble descends, corresponding with the fall of the
mercury in the barometer. When, on the approach of fine weath-
er, the atmosphere becomes calm, and of its usual density and
elevation, the water being forced into the tube cf, by the increased
pressure causes the baroscope to sink, and consequently the bub-
ble to rise. It is said that this instrument will show alterations in
the air 1200 times more accurately than the common barometer.
The inventor, Mr. Caswell of Oxford, observes that the bubble
is seldom known to stand still even for a minute ; that a small
blast of wind that cannot be heard in a chamber will sensibly
make it sink, and that a cloud passing over it always makes it de-
scend. The greatest objection to this very simple instrument is,
it is liable to be affected by the expansion of the included air by
heat.

125

CHAPTER II.

Winds.

"He spoke, and, at his call, a mighty Wind,
Not like the fitful blast, with fury blind,
But deep, majestic, in its destined course,
Sprung with unerring, unrelenting force,
From the bright East. Tides duly ebbed and flowed;
Stars rose and set; and new hoiizons glowed;
Yet still it blew." Rogers.

Ix the preceding chapter we have alluded to the weight and
decreasing density of the air. In the present we shall consider
it in its relations to heat and moisture, in which connection it per-
forms a most important part in the economy of nature. Air, like
all material bodies, expands when heated, and thus its specific
gravity being lessened, it rises. Every one is familiar with this
fact. The little whirligigs placed, on stoves, are turned by the
ascent of the heated air, and the draft of chimneys and pipes de-
pends upon the same principle. We might infer that if air ex-
pands upon being heated, it will part with this heat on being con-
densed. This is the fact, upon forcing a close fitting piston down
a tight tube, suddenly compressing the air before it, a heat is
evolved, sufficient to inflame good tinder. We well remember
in our younger days performing this feat, using a leaden tube for
the pipe, and a bit of wood with a circular and greased "leather
nailed to one end, for a piston, placing the "punk" in the folds
of the leather.

The ascent of heated air from the earth is one of those silent
and often .unobserved agencies employed to produce a general
equilibrium in the temperature and moisture of the earth. The
air itself being transparent, is scarcely heated by the.passage of
the suns rays, but the stratum nearest the earth absorbing a por-
tion of the heat, rises and gives place to a colder portion, which
in its turn is displaced by another, and thus the excessive heat
which, in some portions of our globe, would parch up the earth
and destroy all life, is rapidly carried off, and a more genial tern-

126

Tin: WORLD.

perature produced. The heated portions of air distribute their
warmth throughout the great body of the atmosphere, and some-
times in the form of winds sweeping over colder regions of the
earth, moderate the rigor of the climate.

Ascending from the earth we find the temperature of the air
constantly diminishes until we arrive at a region of frost, the
limit of which, is called the term of perpetual congelation. The
height of the term of congelation varies for every change of
latitude. In the following diagram taking A B, for the height of

\

B 0° 10° 20° 30° 40° 50° 60° 70° 80° C

perpetual congelation at the equator, and B C, for the line of lati-
tudes, then the decrease in the height of the term of congelation
from the equator to the poles, may be represented by the several
parallels bounded by the curved line A C. The region of per-
petual frost at the equator is at a height of 3 miles, at a distance
of 35° from the equator, about 2 miles, at 54° about 1 mile, at
80° very near the surface of the earth, and at 90° the surface of
the earth. It will be well to fix in the mind, the limits here as-
signed, as we shall often refer to this varying elevation in explain-
ing the phenomena of rain, hail and snow. The clouds almost
always float below the term of congelation.

Although the temperature of the surrounding atmosphere is

TEMPERATURE OF VALLEYS. 127

generally colder as we ascend, yet from local circumstances the
heat of the earth being increased, the air becomes sometimes
very mild even in elevated districts. Valleys, it is well known, are
warmer than level plains in the same latitude on account of the
reflection of the sun's heat from neighboring hills and mountains.
In Switzerland, instances occur of spots of verdure in the midst
of perpetual snow and glaciers. We give below a view of the
glacier of Grindelwald in the Canton of Berne. Here woods
and meadgws border close upon the immense fields of ice, which

descending from the upper regions, cover an extent of about 1200
square miles of territory. The ice is seen presenting innumer-
able peaks in the gorge between the mountains. It is said that
there are plains in the Hhnalayah mountains 15,000 feet above
the level of the sea which produce fine pasturages.

Air when put in motion produces what is called wind, and the
variable distribution of heat throughout the atmosphere is the
main cause of wind, or flow of the air, for thus the local density
is constantly affected, and the equilibrium of the mass disturbed.
Winds are exhibited in various forms, breezes, high winds, gales,
hurricanes and tornadoes. These varieties depend chiefly upon
their different velocities, a velocity of twelve miles an hour mak-
ing a strong breeze; sixty miles, a high wind; one hundred miles
a hurricane.

The force of the wind when moving with the velocitvof a
hurricane or tornado, is almost incredible ; when we speak of the
geological changes that have passed over the face of our globe

128 , THE WORLD.

during its past existence, we shall have occasion to refer to their
agency ; no power can resist the combined action of winds and
waves. Hurricanes and high winds are generally characterized by
a whirling motion producing the phenomena called whirlwinds,
these often exhibit the most incredible power,- uprooting huge
trees, and whirling their dismembered fragments into the air,
unroofing houses, and even raising aloft animals, and heavy carts.
The great gales of the ocean manifestly exhibit more or less of
this rotary motion. Such are the the hurricanes whioh annually
sweep over the Indian seas and along the Atlantic coast.

Our limits will not permit us to be very extended upon this sub-
ject, and we shall therefore briefly notice some of the more pecu-
liar winds, and we commence with the land and sea breezes.
These are occasionally met with in every latitude, but are con-
stantly observed near the shores of the continent, and of the lar-
ger islands within the tropics. In these sultry regions, as the
day advances, a refreshing wind blows from the sea, and is suc-
ceeded by an opposite current from the interior of the land on the
approach of evening. The cause of these diurnal winds is obvi-
ous. The change of temperature between the night and day on
land often varies more than 40° or 50° Fahr., while at the same
time on the water it seldom varies more than 1° or 2°. The
large body of heated air over the land, rising continually during
the day, a denser and colder portion rushes in from over the wa-"
ter to supply its place, causing the sea breeze. During the night
the ground cools much more rapidly than the water, and the lower
stratum of atmosphere thus soon becomes colder than at sea,
consequently a stream of air thus flows toward the sea, displacing
the lighter and warmer air, producing the land breeze. This breeze
is never as powerful as the sea breeze, but is much colder. Every
oij.3 who is familiar with these breezes must have noticed the pe-
riod of peculiar languor and depression, between the change from
the sea to the land breeze.

Dr. Robinson mentions an experiment which illustrates the
cause of land and sea breezes very prettily. If we place a hot
stone in a room, and hold near it a candle just extinguished, wre
will see the smoke move toward the stone, and then ascend up

INDS; 129

from it, precisely similar to the movement of the air, heated by
contact with the land, and perhaps the sloping sides of moun-
tains. The most remarkable aerial currents, and of the greatest
importance in navigation, are the trade winds, which, within the
tropics, blow continually from the east, though with variable force,
and declining north and south, according to the latitude, and sea-
son of the year. The primary cause of the trade winds is anala-
gfrus to that of the lan,d and sea breezes, though much more ex-
tensive, and maintaining a constant direction, and likewise united
with the influence of another cause, viz : the rotation of the
earth. We have already had occasion to remark that within the
two tropics lies a belt, over some part of which the sun is verti-
cal at noon, at all seasons of the year, hence this equatorial belt,
in the torrid zone, is continually heated by the sun, and a large
body of air warmed by contact with the heated ground, rises con-
stantly to the upper regions. Its place is supplied by colder air
moving along the surface of the earth, from the colder northern
and southern climates. The effect of this would be to produce
a north wind north of the equator, and a south wind south of the
equator. The portion of air thus transferred from the higher lati-
tudes to the equator has a slower diurnal motion than at the equa-
torial regions. Perhaps a diagram will make this more plain.

Let P be ane of the poles of the earth, A B a parallel of latitude;
and E E, the equator. Now it is eviden^that the diurnal move-
ment of a body attached to the parallel A B, is slower than one
at the equator E E, since the equatorial belt or circle, is of much
greater circumference than the circle of latitude, and both are

130 THE WORLD.

moved over in the same time. If therefore, a body, still retain-
ing the quantity of motion it had while upon A B, should sud-
denly be placed upon E E, it is evident that the excess of motion
at E E would leave it behind. This is actually the case with the
colder air rushing from the higher latitudes to fill the space vaca-
ted by the ascent of heated air Within the tropics. The air thus
transferred, does not acquire at once the motion of the equatorial
regions, and consequently lags behind, or-the earth moves uncfer
it, and thus since the earth moves from west to east upon its axis,
it gives the appearance of a wind coming from the opposite quar-
ter, i. e. from the eastward. But, as we have seen before, these
winds had a direction from the north, at all places uorth of the
equator, and from the south, at all places south of the equator,
'Combining the two therefore, we will have a constant north-east
wind one side of the equator, and south-east the other; these two
winds, meeting at the equator, will flow constantly eastward, or
destroy each other and produce a calm. Such is the character of
that general wind, which encircles the globe, flowing with slight
deviations, constantly from the east, and spreading over a zone of
more than 50° in breadth. It sweeps the Atlantic ocean from the
coast of Africa to Brazil, and the Pacific from Panama to the
Phillipine islands, and New Holland; and again over the Indian
sea partially, from Summatra to Zanguebar ; here however its
direction is curiously varied, owing to the peculiar locality of this
ocean.

The course of the trade winds is changed or interrupted by high
lands, thus calms and variable winds prevail at the Cape Verd
islands, being under the the lee of the African shore, and an eddy,
or counter current of air from the south-west, is generated under
the coast of Guinea. The lofty barrier of the Andes shelters
the sea on the Peruvian shores from the trade winds, which are
not felt until a ship has sailed eighty leagues westward, but the
'intervening space is occupied by a wind from the south. The
heated air of the tropi$s after becoming somewhat cooler in its
passage towards the temperate regions, descends to the earth
still retaining in a great measure, its equatorial velocity, conse-
quently, it sweeps over the surface of the earth in the same di-

rection iu which it is turning, but somewhat faster; this gives the
appearance of a westerly wind of considerable force and regular-
ity, According to Robbms, a westerly wind almost constantly
prevails in about latitude 60° S. in the Pacific ocean. In Hud*
son's Bay, westerly winds prevail three -fourths of the year, as also
in Kamschatka. Still farther north, as at Melville island, the
north, and north-west winds prevail. On account of these winds,
the Atlantic may be crossed eastward in about half the time of
returning westward. The existence of the upper current of the
trade winds was shown in a striking manner at the eruptions of
the volcano in the island of St. Vincent in 1812. The trade
winds blow with great force from Barbadoes to St. Vincent, but
ashes erupted by the volcano fell in profusion from a great height
upon Barbadoes, which is about 150 miles westward. Since the
westerly winds which prevail in the higher latitudes are caused
by bodies of air from the torrid zone, which often descend to the
earth before the heat is quite gone, such winds are generally
warm, and on the same principle winds which blow directly from
the arctic pole, are intensely cold, and, as they must appear
from the rotation of the earth, to come from the north-east, our
easterly and north-easterly winds are always severely cold.

We will now consider the causes which result in changing the
direction of the trade winds in the Indian ocean, producing what
are termed the monsoons. When it is summer in the northern
hemisphere the great body of land above the Indian ocean be-
coming more heated than the sea, a breeze sets towards the land,
which, modified by the rotation of the earth, gives a strong south-
east wind. On the contrary, when it is winter in the northern
latitudes, the great body of water, as also the vast island of New
Holland, becoming more heated than the continent farther north,
a wind sweeps over the Indian and southern oceans, whose
general direction is south-west ; this wind not being opposed in
direction to the rotation of the earth, is more powerful than the
other. The interval which separates the monsoons is varia-
ble, but occurs generally near the equinoxes, during this interval,
violent gales occur called Typhoons.

According to Mr, Redfield, who has most ^.bly and successfully

132 THE WORLD.

investigated the phenomena of the great storms which traverse
the Atlantic coast, they may .be traced to the N. E. of the West
India islands, and are from thence, drifted to the westward on a
track which inclines generally to the northward and eastward*
The rate of progression varies from 12 to 30 miles per hour, and
the storm whirls or blows from right to left, in a horizontal circuit,
on a vertical and some what inclined axis of rotation which is
carried forward by the storm. Mr. Espy has proposed a theory
which to us appears at variance with the facts derived from gen*
eral observation, and independent of any hypothesis. According
to this doctrine, it is alleged that during hurricanes, the wind, in-
stead of blowing in a circle, rushes directly from the exterior to-
wards the centre, to supply a vertical current under influence of
the suction, or vacuum power caused by the rarefaction and as-
cent of air, consequent from the extrication of the latent heat of
vapor during condensation. This theory has been ably defended
by Dr. Hare. The rotary theory of storms is now pretty generally
acknowledged, and has been advocated by Mr. Redfield, Sir
John Herschel, Lieut. Col. Reid, Prof. Dove of Prussia, and
Mr. Alex. Thorn. The latter gentleman has published a book
ttn the nature and course of storms, in which, he traces the ori-
gin, and describes the phenomena, of the great hurricanes annu-
ally occurring in the Indian ocean, showing them to be vast cir-
cuits of wind, revolving in a particular direction with unerring
regularity ; that they move from about latitude 10° S. by a south-
westerly track, curving towards the tropic. Their diurnal rate of
progression diminishes as they recede from the equator. These
hurricanes are formed by the westerly monsoons, and the S. E.
trade winds; the following diagram is extracted from Mr. Thorns'
work, and will illustrate the manner in which these storms are
generated.

When the hurricanes are first noticed they are from 400 to
500 and even 600 miles in extent, or diameter, and consequently,
as the space between the monsoons and the trades is seldom
more than 100 miles, the outer portions of the circle must be in-
volved in the two winds for tht space of two hundred miles on
each side. Each wind therefore communicates a part, if not the

HtTRRICANES. 13&

whole of its motion, in a tangential direction, and by their reverse
directions produce a uniform circular motion. If the south-east
S. E. Trades.

Westerly Monsoons,
trade impinges upon one side at the rate of 30 miles per hour,
and the monsoon at the same velocity on the other, the amount,
converted into a rotary motion, would be equal to 60 miles at the
exterior. The stormy revolution appears to extend to a great
height, passing over the lofty mountains of the Isle of Bourbon
and the Mauritias without being destroyed, though these arrest the
trade winds. The same cause which produces the gyratory mo-
tion carries the storm forward.

The awful phenomena developed during a hurricane, depend
upon the sudden reductions of the masses of air involved in it,
of different temperatures, to the same standard, producing the
most terrific exhibitions of thunder and lightning, attended with
rain, hail &c. The trade winds are cool, but the monsoons are
hot and humid. In most hurricanes, the fall of the mercurial
column is equal to 1 inch, or even 2 inches, and the velocity of
the wind just entering the focus as great as 150 miles an hour.
In the focus of a rotary storm the horizontal direction of the wind
suddenly ceases, and often, the storm appears, to one ignorant of
its nature, to have passsed off, when suddenly it commences again,
with the utmost fury, and at a point of the compass opposite to
where it left off. This fact is strikingly noticeable even in the
small hurricanes which in the autumn and spring, blow over our
western lakes, and we have several times witnessed a violent
hail and thunder storm, during which the wind raged with the

134

THE

utmost fury, to apparently return with the wind in quite the op1-
posite direction, after an interval of 15 or 20 minutes of perfect
calm. The cause of these calms and the course of the air in the
focus of a circular storm, is represented in the diagram.

We have scarcely room to add a description of the famous
Rodriguez hurricane of April 1843. Such a fleet of wrecks from
one storm never was seen before, having 14 or 15 vessels entan-
gled its stormy circuit, some on its skirts, others crossing its path
and following its wake, some rushing into the very focus and scud-
ding around the vortex till rendered perfectly unmanageable by
the fury of the sea and wind ; its course could be tracked for
3500 miles, demonstrating beyond a doubt, that it was a vast
whirlwind. We give a diagram of its position on the 4th of April,
when its centre had just passed over the island of Rodriguez.
The arrows represent the positions of the vessels and the direc-
tion of the wind, as gathered from the log-books. Though some
of these vessels were but a few hundred miles from each other,
yet they had the wind from opposite quarters.

Besides the winds which we have mentioned we may enumerate
among local winds, or winds which affect only particular sections
of country, the Sirrocco, a hot wind, moist and relaxing, which
Visits Naples and the south of Italy, blowing from the opposite
shores of the Mediteranean. This wind is very unhealthy; during
its continuance all nature seems to languish, the vegetation droops
and dies, and the animal spirits are too much exhausted to per-

VARIOUS WINDS. 135

mil any exertion. The Harmattan is a cold dry wind of very

parching quality, frequent in Africa; it is a periodical wind of un-
certain continuance, and is attended by ft thick fog or haze,which
either wholly obscures the sun or makes it appear a faint red easily
borne by the eye. It is so dry that the eyes, lips, palate &c., are
parched and painful, causing the skin to shrink and crack, and
sometimes to peel off. It is however considered as an effectual
cure for some diseases. The Samielor Simoon, is a burning, pes-
tilential blast, extremely arid, which springs up at times in the
vast deserts of Africa, and rushes with tremendous fury, involving
whole pillars of sand. It produces instantaneous death, and
mortifies the body so effectually, that the limbs may be separated
without difficulty , The camels seem to have an almost instinctive

136 THK WORLD,

notice oi its approach, and are so well aware of the noxious quali-
ties arising from its extreme dryness, that they bury their noses
in the sand to avoid breathing it. So impetuous is this wind that
its fury is past in a few moments.

We have now briefly described the more prominent winds
which blow over the surface of our globe. We shall, when con-
sidering the changes which have modified, or entirely altered the
face of the various continents and islands, which at present, form
the •* dry land" of our planet, perceive that they have acted a
most important part. No force can resist the perpetual assault of
the winds and waves. The sea, lashed into fury by the careering
tempest, forces its way through barriers of porphyry and granite,
undermines the rocky cliffs, and piles immense dunes or sand-
hills along the low shores. Beneath the fine sands of the bound-
less eastern deserts, the monuments of ancient Egypt, her sta-
tues and sculptured temples, have lain hidden for ages, but the
dry impalpable powder has fallen harmless upon them, and now,
when the curious traveler from the western world, from lands
unknown to the hierophants, uncovers with careful hands the
buried tombs of kings, he beholds the color glowing upon the
walls as bright, and perfect, as when first laid on by the Egyptian
artist 3000 years ago ; and the winged globe and heads of Isis
as sharply outlined as though chiseled but yesterday.

137

CHAPTER III.

Formation of Clouds and Dew.

" The clouds consign their treasures to the fields,
And, softly shaking on the dimpled pool
Prelusive drops, let all their moisture flow
In large effusion o'er the freshen'd world."

Thomson.

THE relations of the atmosphere to water are very important
and numerous. The various winds as they sweep over large
tracts of country, or the ocean, become charged with moisture,
which they bear with them to the higher regions, to be there em-
ployed in the formation of clouds, or rain. The formation and
dissolution of clouds, produces all the varied train of meteoro-
logical phenomena. The humidity suspended in the atmosphere
is derived by exhalation partly from the land, but ultimately from
the vast expanse of the ocean. The moisture, deposited by the
air is in the form of minute globules, which remain suspended, or
subsicfe slowly, constituting a cloud. When it comes near us,
whether it hovers on the tops of the hills, or spreads over the
valleys, it receives the name of &fog; when deposited from the
air in a clear night, upon the surface of the ground, or bodies ex-
posed to the air, it is called dew.

In order to explain more clearly the formation of clouds and
also the deposition of dew, let us consider in what manner the
capacity of air for moisture will be affected either by heat or cold.
By capacity, we mean power of stowing away so as to render in-
visible. As a general rule, we find the capacity of air for mois-
ture increased by heating, and dimished by cooling, it being ca-
pable of taking up and holding in an invisible state, a greater
quantity of water when heated, than it can retain when cooled.
Although the capacity of air for moisture is increased by heating,
yet it is not proportional to the heat, but increases in a faster ratio.

138 THE WORT, P.

For instance, an increase of temperature 10°, of air already heated
to 70°, will increase its capacity for water much more than the
same increase to air heated to only 40°. The converse of this
is also true, the cooling of hot air diminishes its capacity for heat,
much faster than the cooling of air already cold. Air in mount-
ing upwards becomes colder, and since every increase of cold is
attended with a dimunition of capacity for moisture, it becomes
proportionally damper, and thus the middle regions of the atmos-
phere become soon charged with moisture, and were it not for a
conservative principle which we will now mention, the heavens
would be perpetually shrouded with clouds ; this principle is, air
in expanding has its capacity for moisture increased, and there-
fore, as the air which is ascending, continually expands from the
dimunition of pressure, it becomes consequently drier and drier.

Clouds are formed either by a watery vapor rising so high as to
reach a degree of cold sufficient to condense it, or from a mix-
ture of warm air with cold, the moisture being derived from the
warmer portion. Fog is nothing more than a cloud formed upon,
or near to, the surface of the earth, and is due to a mixture of
warm and cold air. Thus in a cold morning we see moisture
deposited from the warm breath of animals, when it comes in
contact with the air. The course of that remarkable body of wa-
ter which is called the Gulf Stream, and which flows in a warm
current from the Gulf of Mexico as far up as the banks of New-
foundland, is marked by a fog, produced by the colder air sweep-
ing over it. Fogs are not common in hot climates, the air being
too warm near the surface of the earth to condense the moisture
faifficiently to form a cloud.

Dew is formed when air charged with moisture comes in con-
tact with a surface in a certain degree colder than itself. The
formation of dew may be very prettily illustrated by bringing a
tumbler of cold water into a warm room, the outside of the tum-
bler will soon be covered with a coat of moisture, deposited from
the warm air which has come in contact with it. In order to
have a copious deposite of dew it is essential that the ground
should be considerably colder than the air above it, and, it is act-
ually found, that upon those nights when the most copious dews

r>BW. 1

*

occur, the ground becomes 12 or 15° colder than the air a few-
feet above it. Dew is deposited very unequally upon various
substances; plants and vegetables, which need this sustenance,
receiving the greatest abundance ; but little is deposited upon the
dry land, still less upon polished metalic bodies, and .none at nil
upon the ocean. The deposition in these cases is proportional lo
the temperature, some bodies growing much colder than others
when exposed to the same cooling influence ; the surface of the
ocean, as wo have before remarked, remains at nearly the same
temperature as the air incumbent upon it.

The surface of the earth is cooled by radiation of the hent it
has received during the day, and thus prepared for the deposition
of the dew. Hence dews are most abundant in a clear night
when the heat radiated from the earth is not intercepted and
thrown back from overhanging clouds. It is from this circum-
stance that the vulgar notion arises that the rays of the moon
have a chilling influence. When the ground becomes cooled by
the radiation of heat from its surface, below 32°, the dew is fro-
zen, and then takes the name of white, or hoar frost.

It will be apparent from what we have said, that dew will occur
most frequently when there is a considerable difference between
the heat of the day and the night. It is on this account that we
seldom have dews either in mid-winter, or mid-summer, i. e. at
the solstices, but generally just after the vernal, and before (he
autumnal equinox, viz : in May, and August. Dew is most co-
pious in those places which are sheltered from the wind, and high
winds therefore are a sure preventive to its formation, and of hoar
frost. Dew and frost occur most frequently in clear weather,
when the radiations of heat from the ground are thrown up inlo
the sky without being again reflected, hence the thinnest screen,
or the shade of a tree is a protection, and a cloth thrown over
delicate plants will preserve, them from frost. The quantity of
moisture precipitated from the atmosphere, depends upon a va-
riety of circumstances ; on the previous dampness of the com-
mingled portions of the fluid, their difference of heat, the eleva-
tion of their mean temperature, and the extent of the combina-
tion which takes place. When- the deposition is slow the very

140 THE WORE.BL

minute, aqueous globules remain suspended. These are found tor
be made up of hollow vesicles, filled with air like a soap bubble ;
and as the air included, is rarefied by the latent heat when the va-
por is condensed, the weight of these vesicles becomes less than
the weight of an equal bulk of air, ami therefore they rise or float,
forming a cloud. When the air within these vesicles bursts, the
drops of rain are formed, which are changed, according to the
sircumslances attending their formation, as regards rapidity and
copiousness, or the state of the medium as to heat, into hail or
snow. In order for the precipitation of moisture necessary to-
form rain, hail, or snow, contending currents must bring vast
fields of air of different temperatures over a given spot, as for
example, when a warm south-east wind encounters a cold north-
wester. In some parts of the world, as in Egypt, part of Chili,
and Peru, it seldom rahis, for there the winds usually blow in
one direction.

Snow is formed by the crystalization of aqueous vapor in-
stead of its formation into drops. It is thus converted into a
white downy substance, which falls gently to the surface, forming1-
in winter a warm covering, confining effectually the heat of the
earth. The snow huts of the natives of Labrador are said to be-
quite warm. Below are figured some of the beautiful forms which
the snow crystals assume in cold climates,

Hail is forme 1 by drops of rain suddenly congealed during their
till, by passing through, a lower stratum of dry and cold air. The

141

most violent hail storms are caused by a sudden transference of
a body of warm air up beyond the term of perpetual congelation,
where the drops of rain are frozen into hail stones. This is some-
times accomplished by means of whirlwinds, by which the hail-
stones being sustained for some time, are occasionally accumula-
ted to a very large size. By referring to our figure of the curve
of perpetual congelation, page 126, it will be understood why
hail storms seldom occur in the equatorial regions, and most fre-
quently in the temperate zones, and seldom or never in the polar
regions. The term of congelation is too high at the equator for
the hot air raised by a whirlwind to pass beyond, or up to it, and
at the polar regions, the air seldom becomes as hot as is required
to form hail storms. Different names have been given to the va-
rious forms of clouds, derived from their appearance and charac-
ter, we will briefly notice them. First, we have, occurring at the
greatest elevation, the Cirrus, or curl-cloud, which is a thin fleecy
vapor, with a waving and striated appearance as shown in the
engraving below. This cloud is frequently called the curl-cloud

from its flexuons form, and ix not unlike a bunch of wool pulled
out into fine pointed ends. After a continuance, of fine weather
the cirrus is often observed at groat heights like a Fine white line
stretching across the r:!--y. The peculiar' form of cirrus shown in
r.*

142

THE WORLD.

the engraving, called vulgarly, mare's tail, is thought to be an in-
dication of violent winds, and the wind is generally from the
quarter towards which the fine extended ends are pointed. When
carefully observed, every particle of the cirrus cloud seems to be
inrnotion, though the whole cloud appears nearly stationary. This
cloud under different circumstances, presents considerable varie-
ty of appearance. After a continuance of clear and fine weath-
er a whitish line of vapor stretched out like a thread, may be ob-
served at a very great height, the ends seeming lost in the horizon,
this is often the first indication of a change from dry to wet
weather. To this line of cloud others are added, or as it were
propagated from the sides in an oblique or transverse direction
the whole having the appearance of net-work.

The Cumulus, is a dense mass of rolling clouds rising from a
horizontal base. The name denotes a heap or pile ; it is some-
times called the stacken-cloud, since the masses of which it is
composed seem stacked or piled together. This cloud is gene-
rally formed during the day, but is desolved at the approach of
evening, it has hence been termed the cloud of day. The Stratus
or fall-cloud is a low cloud seeming to rest upon the earth, hence
its name stratus, a covering. This cloud is generally formed
during the night, and is sometimes called the cloud of night, it
is generally dissipated by the rays of the sun and in tin's case is

CLOUDS. 143

considered indicative of fine weather. Among this variety of
clouds are included those fogs and creeping mists that in summer
evenings fill the valleys, remain during the night, and disappear
in the morning. The formation of the cumulus is best viewed
in fine settled weather, about sunrise or a little after. Small
specks of cloud will be seen in the atmosphere, which seem to be
the result of the gatherings of the stratus or evening mists, which
rising in the morning form into small clouds whilst the rest of the
sky becomes clearer. About sunrise two or more of these unite
and form a stacken-cloud. In the evening it again subsides giv-
ing place to the stratus or fall cloud. In our engraving the cu-
mulus is seen above and the stratus nearer the horizon. Some
varieties of the cumulus are supposed to be closely connected
with electrical phenomena. The hemispherical form is more
perfect in fine than in changeable weather.

The Cirro-stratus is often called a mackerel sky, and is seen
in fine summer evenings, it is generallly called the wave-cloud
on account of its frequent alterations of figure. It is formed ut
a great height and presents many varieties and is sometimes seen
as a thin extensive sheet covering the heavens, and it is this form
of the cloud in which the halos appear, which are thought to in-
dicate rain, and when the sun sets apparently shrouded in a dense
stratum of this cloud it is a .mre indication of a wet morning. A

144 THZ WORLD,

form of the cirro-stratus called the cymoid cirro-stratus, cosfsting
df rows of little clouds curved in ft peculiar manner, is a sure in-
dication of corning storms. Its most common form however is a
flat horizontal <"-lond consisting of waving bars or streaks, con-
fused in the middle, but more di-tinct at the ends or edges.

The Cirro-c-:;-iit:d-n-s consists of extensive beds of small white
clouds called in Germany, liitla sheep. It is sometimes called th«
sender i. e. su ne'er-cloud. When the component clouds towards
evening are large and well defined, and distinct from each other
it is considered to indicate fine weather, on the contrary, when
the little cloud-i are round and compact, accompanied by the cu-
mulo-stratus (sue next figure), it is a sure indication of an ap-
proaching storm. |t is to this cloud that Milton alludes.

" To behold the wandering moon,
Riding near her highest noon,
Like one that hath been led astruy
Th. rough the heaven's wide pathless way;
And oft as if her head she bow'd,
Stooping through a fleecy cloud."

The cirro-Guniulud generally is a forerunner of warmth, indi-
cating, particularly when the little clouds are small and round, in
summer an increase of temperature, and in winter the breaking
up of a frost. The connection of this cloud with thunder stornyi

145

has been frequently noticed by poets, in rainy and changeable
weather it has a light fleecy texture, and is irregular in the form
of its component parts, approaching to the cirro-stratus.

The C.!.)ii:»lo-!t'rnin.s, or twain-doud usually presents an hori-
zontal base upon which the cloud appears heaped or piled up, it
is of common occurrence p evious to rain, arid sojn. ti:)i'-s changes
into the the nimbus or rain-cloud. In our fi<rure, the cuinulo-
stratus is shown at the left and ni inline at the right. The eumu-
lo-stratus is usually formed out of !'ic cumulus, which grows
denser and spivails out laterally until it cveiliangs its base, while
the tops remainingdistinetseem like yo many snow-capped moun-
tains, or rocks piled up. When the curuulo-.'-t.ratus increases in
density and hiaekne-'a, indicating rain, the nimbus or rain-cloud
is formed. As soon as the actual rain commences the blackness ia
changed into a dark gray orshitv color. After the rain the clouds
separate and form again cumuli, cirri, and cirro-cumuli, which
float in the upper regions of the atmosphere, while the broken
fragments of the nimbus sail along- in the currents of wind
below.

It often happens that a cloud, in descending, enters a stratum
of air warmer than itself and is again converted into vapor and

14G THE WORLD.

absorbed, a remarkable appearance of this sort is observed on
the Table Mountain at the Cape of Good Hope. " Its flattop, call-
ed the Table Land, is about two miles in length from east to west,
and of various breadths, but nowhere exceeding a mile. The
height is estimated at 3500 feet above the sea. It is a common
saying among the inhabitants of Cape Town, that when the
Devil spreads his table cloth upon the mountain you may look for
a strong south-east wind. In the whole system of meteorology
there is not a more infallible prognostic. The Devil's tablecloth is
a thin sheet of white vapor which is seen reaching over the edge
of the precipice, while the sky all around is clear and unclouded.
The rapidity of its descent, resembles that of water pouring over
the face of a rock. The air, at the same time begins to be agi-
tated in the valley, and in less than half an hour, the whole town
is involved in dust and darkness. Instantly the streets are de-
serted, every window and door is shut up, and Cape Town is as
still as if it were visited by the plague. Sometimes, instead of a
sheet of vapor an immense cloud envelopes the mountain, and
stretching out on all sides like a magnificent canopy, shades the
town and adjacent country from the sun. The inferior boundary
of this cloud is regulated, probably, by various circumstances,
among others, by the strength of the wind, and the temperature
of the air in the Table Valley. The influence of the latter is to
be inferred from the fact, that though the cloud never descends
more than half way into the hot parched amphitheatre of Cape
Town, it may be observed on the side of Camp's Bay, rolling
down in immense volumes to the very sea, over which it some-
times stretches farther than the eye can follow it. Nothing can
be more singular than the appearance of this cloud. It is con-
tinually rushing down to a certain point on the side of the moun-
tain and there vanishing. Fleeces are seen from time to time,
torn from its skirts by the strength of the wind, floating and
whirling, as it were in a vortex, over the town, and then gradu-
ally dissolving away. But the main body remains, as it were,
nailed to the mountain, and bids defiance to the utmost efforts of
the gale. There is a constant verdure maintained on this moun-
tain from the moisture deposited from the atmosphere

Ct.lMATK. 14?

•

-

CHAPTER IV,

Climate.

•

"The body, moulded by the clime, endures
Equator heat, or hypoborean frost,
Except by habits foreign to its turn,
Unwise you counteract its forming pow'r."

Armstrong.

IN the present chapter we shall very briefly consider the prom-
inent causes which affect the climate of the various portions of
the earth's surface. The subject is a very important one and we
can do little else than give the great outlines, and must therefore
refer the reader to the more elaborate works of Leslie, Daniell,
and Kaemtz.

The primary cause of all heat upon the surface of the earth,
and its superincumbent atmosphere, is the sun, whose rays may
also be regarded as the source of all life upon our planet. In the
preceding pages, we have, somewhat at length, illustrated the man-
ner in which the sun apparently changes its position in the heavens,
traversing during the year through the twelve signs of the Zodi-
ac, in the path called the ecliptic, which is inclined at an angle of
23° 28' to the celestial equator, which it crosses in two opposite
points called the equinoctial points.

The celestial equator, we have shown to be in the same plane
as the equator upon the earth, consequently, as the earth turns on
its axis, it will happen that the rays of the sun, whenever it may be
situated in the celestial equator, L c. at the time of the equinoxes,
will fall vertically, or perpendicularly upon all those places situated
upon or near to the terrestrial equator. Twice a year, viz : on
the 21st of March and the 21st of September, the sun is in those
points of the ecliptic which cross the equator, and at this time
its rays aro vertical at noon at the equator, as we have just de-

148 TH£ w<mtr>.

scribed. At these seasons of the year the changes from winter1
to spring1, and summer to autumn, commence, and the sun is said
to be crossing the line.

The distribution of heat in the neighborhood of the equator is
tolerably equal, for twice during the year, viz : March 21st and
September 21st, the sun's rays fall vertically, and they do not
fall very obliquely at any time between these two periods. From
the 21st of March, the sun begins to move northword of the equa-
tor apparently, until at the 2lst of June, its angular distance from
the equator amounts to 23° 28'. This is the angle which the line
S S' makes witli the line E E', eeo the figure on page 57, the
former representing the plane of the ecliptic, the latter the plane
of the equator. At this time, as the earth turns on its axis, the
sun is vertical at noon at nil those places which lie in a cirele
drawn upon its surface parallel to the equator, and at an angular
distance of 23° 28' north of it. This circle is called the tropic of
Cancer, for a reason we have already explained. From the 21st
of June to the 21 st of September, the sun approaches the equa-
tor, which it crosses on the latter named day, it then moves far-
ther south, until, on the 21st of December, its angular distance
from the equator becomes 23° 28', and, if we suppose a circle
drawn upon the earth at a distance of 23° 28' from the equator,
but south of it, the sun will now be vertical at all places situated
on or near to this circle, which, for reasons already given, is called
the tropic of Capricorn. All places therefore lying upon these
tropics, receive once in the year, the sun's rays perpendicularly at
mid-day, this being on the 2"lst of June for the tropic of Cancer
and the 21st of September for the tropic of Capricorn. At all
places within these two tropics the sun is vertical at noon twice
in the year j and at all places without or beyond them, it is never
vertical. The nearer \vc approach the tropic?, leaving the equa-
tor, the more marked are the difTerentsessons of the yf or, and for
the following reason; once during ths year, as we have just remark-
ed, the sun's rays fall vertically nt the tropics, and once they
make an angle of 47° or tw'ce ;23n 2;:;', witti the d?:-prtion of tho
plumb-line, and which is the angle S S' C', see fiVuro on page
57, falling conrequcntlv, with considerable obliquity. The hot-

test and coldest seasons being separated by a period of half a year*
differ very considerably from each other in their temperature.
The whole terrestrial zone lying between these two tropics is
called the hot zone, or torrid zone. When the sun's distance from
the equator north is the greatest possible, i. e., when it is in the
tropic of Cancer or at the point VI, see figure, page 80, the north
pole of the earth is illuminated, and the south pole in darkness, as-
represented in the figure, page 109. If we suppose a circle traced
upon the earth as shown at c d, it is evident that as the sun
now illuminates all within this circle, the day will be to a specta-
tor situated upon it, 24 hours in length, or in other words visible
during a complete revolution of the earth on its axis. A similar
circle shown at g /i, indicates the position in the southern
hemisphere where the longest day is 24 hours. These two cir-
cles are called, the former the Arctic, and the latter the Antarctic,,
Hie former is situated 23° 23' from the north pole, and conse-
quently 6G° 32' north of the equator, and the latter at the same
distance from the south pole, and south of the equator. The
terrestrial zones included between the tropics and the polar cir-
cles, are called the northern and southern temperate zones. The
four seasons of the year are most strongly characterized in these
zooies, and the general rule for the di munition of heat is, directly
n.s tke distance from the equator. Within the polar circles are
the northern and southern frigid zones. As the earth turns upon
its axis from west to east, the sun is apparently caused to rise in
the east, move over the heavens, and set in the west, thus pro-
ducing the alternation between day and night. During the day,
the surface of the earth is warmed by the rays of the sun, but
when these are withdrawn at night, the heat is radiated to the
heavens and lost, daring the night therefore the surface of the
earth is cooled. We shall presently see that the vicissitudes in
ciiraate varying with the latitude, are mainly due to the unequal
longths of day and nigh?. Under the equator the days and nights
are very nearly equal, throughout the year, each lasting 12 hours.
As soon, however, as we leave the equator, the length of the day
varies according to the season of the year, and the difference be-
tween the day and night, becomes more striking as we approach

150 THE WOTU.D.

nearer the poles. The following table exhibits the length of the
longest day for different geographical latitudes'.

Polar elevation. Length of the longest day.

0 . . ". . 12 hours,

16° 44' 13

30° 48' 14

49° 22' 16

63° 2.3' 20

66° 32' 24

67° 23' 1 month,

73° 39' 3 months,

90° G months.

Upon examining this table it will be perceived that within the
tropics, the length of the longest day never varies much from that
of the night, and hence, as before observed, the temperature is
tolerably equal. In higher latitudes (.he rays of the sun strike
more obliquely than within the tropics, yet the day so much ex-
ceeding the night, more heat is gained during the day than is ra-
diated during the night, and thus, what is lost in intensity, is gained
in the length or duration, and it thus happens that during the
summer it may be very hot, even at places far removed from the
equator. At St. Petersburg!!, for instance, during a hot summer
the thermometer frequently rises to 86°. On the other hand, in
winter, at the same latitudes, the days become as much shorter
than the nights, as the nights were previously shorter than the days;
hence, since the sun's rays fall very obliquely, and are therefore
very feeble in their action, the earth radiating much more heat at
night than it receives during the day, the winter temperature is
very low, the difference between winter and summer tempera-
ture will therefore, generally be greater, the farther we remove
from the equator.

" At Bogota, which is 40° 35' N. of the equator the difference
of temperature between the hottest and coldest month amounts to
only 3° ; in Mexico (19° 25' N. lat.) this difference is 14° ; at
Paris, (48° 50' N. lat.) 48°, and for St. Petersburgh, (59° 5G' N.
lat.) 57°."

It appears from what has been said, that within a distance of 10
or 15 degrees of the equator or equinoctial line, the difference be-
tween summer and wiivter temperature is trifling, but when we

CLIMATE. 151

get as far north as the tropics, this differencee becomes very sen-
sible, and it has been truly observed, that the torrid zone may be
divided in three, viz : the equatorial belt, extending 10 or 15 de-
grees from the equator, and the two belts north, and south, be-
tween this and the tropics. The equatorial belt, properly so called,
is te mperate compared with the two others, the zone of the tropic
of Cancer being the hottest and least habitable part of the globe.
The greatest natural heat of which we are aware, has been ob-
served at Bagdad, at 33 degrees of N. lat, being 111° Fahrenheit.
There are many reasons why the equatorial belt should have a
uniform and somewhat mild temperature ; the clouds, the great
rains, the nights naturally cool and equal in length to the days,
and the great evaporations. As we go farther from the equator
the difference between the summer and winter temperature be-
comes more marked, the summers being, on account of the pro-
tracted heat of the day, very warm even in high latitudes, and the
winters extremely cold. Thus, even as far from the equator as
the 65th parallel of latitude, the power of the solar beams accu-
mulating through the long days, produces an effect which might
be expected only in the torrid zone. There have been examples
of forests having been set on fire, and of the pitch melting on the
sides of ships. Notwithstanding the general law of the decrease of
mean temperature as we recede from the equator, yet it is impos-
sible to draw any conclusion as to the climatic relations of a place
from its geographical latitude. If the earth's surface was entirely
homogeneous, either covered by water, or by land, possessing
the same capacity for heat, then the geographical latitude of a
place would determine its climate, and all places having the same
latitude would have a similar climate. This however, is not the
case, for although the local temperature of a country depends
very much upon its latitude, yet the nature of its surface, the
proportion of humidity, the distance from the sea, or from lakes
or mountains, and its elevation above the ocean, and the nature
of the prevailing winds, all have a share in determining the cli-
mate. The decrease of heat as we recede from the equator fol-
lows different laws in the two hemispheres, being greater in the
southern than in the northern, and is also affected by the longi-

152 THE WORLD.

tilde. The true distribution of heat over the earth's surface can
therefore only be determined by a long series of observations.
Baron Hurabolt with unwearied zeal, has collected the data for,
and laid the foundation cf, a scientific meteorology. The instru-
ment employed to measure the intensity of heat, called a ther-
mometer is to well known to need any description here. The
thermometer in ordinary use is what is called Fahrenheit's, the
scale being graduated to show 212° for the heat of boiling wa-
ter, and 32° for the temperature of melting ice, or freezing water.
The zero or commencement of the scale, is the temperature of a
mixture of salt and ice, or snow, and which was once supposed to
be the greatest artificial cold. The thermometer called Reau-
mer's is used in some parts of the continent of Europe, the freez-
ing point of water being zero, or the commencement of the scale,
and the space between this and the boiling point of water is di-
vided into 80°. The thermometer now used in France, and the
greater part of the continent of Europe, is called Centrigrade ;
the scale of this thermometer is graduated into 100 degrees from
the freezing, to the boiLng point of water ; this division of the
.scale appears the most natural, and has been adopted by law in
the state of New York.

In employing the thermometer to observe the general tempera-
ture of the air at any particular season of the year, it will gener-
ally be sufficient to make two observations in the morning, viz:
at 4h, and lOh, and two in the afternoon at the same hours, the
mean of the observations will give the mean temperature for
the day very exactly ; thus, suppose the observations made at
these hours to be 50°, 80°, 90°, and 60°, adding these all together,
and dividing their sum 280°, by 4 gives 70° for the mean tem-
perature of the day. When we know the mean temperature of
all the days of a month, we can in like manner determine the
mean temperature of that month. We can likewise determine
in a similar manner the mean temperature of the year, or of
summer, and winter. The mean annual temperature, of a place
not subject to very great local changes, such as the clearing up
of forests, or drying up of streams and rivers, is very nearly con-
stant. Thus, the extreme difference of mean annual tempera-

CLIMATE.

153

lure of Paris for a series of 16 years was only 4°. We can thus
by a series of well directed observations, determine the general
climatic relations of various continents, and the result of such ob-
servations are in some instances very different from what would
be inferred from mere theoretical considerations. It is found that
the decrease of heat as we recede from the equator, follows dif-
ferent laws in the two hemispheres. The subjoined table shows
the mean annual temperatures of Western Europe and North
America, continued from the equator.

Latitude.

Old World.

New W.orld.

Difference.

0°
20
30
40
50
60
70

81.5°
77.9
70.7
63.5
50.9
41.0
33.0

81.5°
77.9
67.1
54.5
38.3
25.0
0.0

0°
0
3.6
9.0
12.6
16.0
33.0

From this table it appears that the decrease of temperature, or
increase of cold is much more rapid in America than in Europe,
Baron Humbolt, who has added more to our knowledge of the
distribution of temperature over the globe, than any other who
has labored in the same boundless field, has proposed a system of
isothermal lines connecting different places having the same mean
annual heat. The differences between the mean annual temper-
ature of places upon the same parallels of latitude are thus pre-
sented to the eye in a very striking manner. On the next page
will be found a little chart of isothermal lines for every 5° in
Mercator's proportions. It will be seen that the mean annual
heat of Eastern Asia and Eastern America, are much nearer than
of Eastern America and Western Europe. A simple inspection
of this map will give a clearer idea of the variation of isother-
mal lines from the parallels of latitude. Thus, for instance, the
mean annual heat at the North Cape, is 32° ; whilst Nain on the
coast of Labrador, 14° south of the North Cape, has a mean an-
nual heat of 25°. The table which we give contains a general
summary of Baron Humbolt's observations deduced from a very
great number of observations, Tho locality of a place very

154

THJ2 VVOKLD.

•I

CLiMATK. 153

much aft'ects the climate, and as a general rule the western sides
of continents and large islands, are warmer than the eastern. Cer<-
tain portions of the globe, which from their nearness to the equa-
tor would be extremely warm, are rendered tolerably cool by their
elevated situations. This is the case with much of the tropical
land hi America, which is so raised that it rivals even European
climates in mildness and agreeable temperature. The air of these
elevated tropical districts is remarkably pure and transparent, and
the winds which sweep over the plains, are cooled by their pass-
age down the snow-capped mountains, which rear their bright
summits to the skies. The vast expanse of table-land, forming
the empire of Mexico is of this character, being elevated 7000
feet above the level of the ocean. This land in many parts has
the fertility of a cultivated garden. The plains of Columbia in
South America, and indeed all along the ridge of the Andes, are
similarly situated. The chart which we have given represents
the direction of .the isothermal lines, or lines connecting places
which have the same mean annual heat. It will be evident that
places may thus be situated on the same isothermal line, which
have very unequal mean temperatures of summer and winter.
We need only refer to the table on page 157, to be convinced of
this. Thus, the mean annual temperature of London, and Cam-
bridge, Mass, is the same, 50°36'; but the mean temperature o
the warmest month at London is 64°40', while at Cambridge it
is 72°86', and of the coldest month, at London 37°76, at Cam-
bridge 29.84, London therefore has a colder summer and a warm-
er winter than Cambridge. The reason of this, is undoubtedly,
the insular situation of the former, for as a general rule the ex-
tremes of temperature are experienced in large inland tracts, and
little felt in islands remote from continents. The difference be-
tween the mean temperature of summer and winter is nothing at
the equator, and increases continually with the latitude. When
the mean annual temperature is low the differences between the
extremes of the seasons is great, and the contrary.

The effect of climate upon the geographical distribution of
plants and animals is very marked. Each, generally has its pe-

156 TKE WORLD.

culiar climate where it thrives best, and beyond certain limits il
ceases to exist. The successive zones of vegetation, as we recede
from the equatorial regions, have sometimes been supposed to be
represented by the different altitudes upon the mountains under
the equator, as it is evident we have in ascending fro in the valleys
to their snow-capped summits, every variety of temperature.
The analogy fails however in one essential point, for as we ascend
the mountains the pressure of the atmosphere is continually di-
minished and it is evident that less nutriment is thus afforded for
the growth of the plant. The influence which the variations of
climate alluded to, must have upon vegetation is very evident,
thus in many parts of Siberia, wheat and rye are raised upon a
soil which is constantly frozen at a depth of three feet, while in
Iceland, where the mean temperature of the year is much warm-
er, and the winter's cold but inconsiderable, it is not possible to
raise any of the ceralia or common grains, as the low summer
temperature does not suffer them to ripen. It is for the same
reason that the vine does not flourish in England, for although
it can endure a tolerably great degree of cold, yet it requires a
hot summer to make the fruit ripen, and yield a drinkable wine.
There is no subject connected with meteorology which requires a
more careful, and studied investigation than that of climates.
So many causes influence the temperature of the air, and some
of them are so variable, that no labor short of a well conducted
series of observations, extending through a long course of years
can give a satisfactory result. In the brief account we have given,
we have been able to present little else than the leading facts,
and must refer the reader to the writings of Leslie, De Candolle,
Mirbel, and Humbolt, for further information.

OF TEMPERATURES,

157

TABLE

Exhibiting iJie mean temperature of various places compiled prin-
cipally from the observations of Baron Alex. Von Humboldt.

Isother-
mal
Bands.

Names of Places.

Lat.

Position.
LoHg^ light.

Mean
tempera-
ture of :
the Year,

o
— 2,00
+26.42
26.96
30.38
32.09
35.08
33.26
38.84
39.92
40.10
40.28

o'

i— i
"*

.2
|

T|

m

Melville Island

o /
74 47
57 8
68 30
46 30
71 0
65 3
63 50
59 56
63 24
55 45
60 27

0 /

110 48w.
61 20 w.
20 47E.
8 23E.:
25 50E.
25 26E.'
20 16E.
31) 19E.
10 22E.
37 32E.
22 18E.

Feet
0
0
1356
6390
0
0
0
6
0
970
0

Nam

Hospice de St. Gothard. . .

Ulea

Umea . .

Drontheim . . . . . .... .. .

Abo

2

o

r-t

Tj*

S

*O

a
I

Upsal

59 51
59 20
46 47
59 55
47 47
55 41
54 17
51 25
50 5
51 32
47 22
55 57
52 14
46 50
53 21
46 5
46 12
49 29
48 12

17 38E.
18 3E.
71 Ow.
10 48E.
10 34E.
12 35E.
2 46w.
59 59w.
14 24E.
9 53E.
8 32E.
3 lOw.
21 2E.
9 30E.
6 19w.
7 26E.
6 SB.
8 28E.
16 22E.

0
0
0
0
3066
0
0
0
0
456
1350
150
0
1876
0
1650
1080
432
420

42.08
42.26
41.74
4280
42.98
45.68
46.23
46.94
49.46
46.94
47.84
47.84
48.56
48.92
49.10
49.28
49.28
50.18
50.54

Convent of Peissenberg

Kendal

Falkland Islands

Warsaw

Coire

Dublin

Berne

158

THE WO&L2A

isother-
mal'
Bands.

Names of Places.

Tosititfn.

fight.

Mean
tempera-
ture of
the Year.

Lat.

Long.

Band from 50° to 59°.

o /
45 46
47 29
42 22
48 50
51 30
51 2
52 22
50 50
52 36
39 56
40 40
39 6
48 39
47 13
39 54
45 28
44 50

0 /

3 SB.
19 IE.
71 7w.
2 20E.
9 5w.
2 22E.
4 50E.
4 22E.
6 22E.
75 lOw.
73 58w.
84 27w.
2 Iw.
1 32w.
116 27E.
9 HE.
0 34w.

Feet
1260
494
0
222
0
0
0
0
0
0
0
510
0
0
0
390
0

o
50.00
51.08 1
50.36
51.0&
50.36
50.54
51.621
51.80
51.80
53.42
53.78
53.78
54.14
54.68
54.86
55.76
56.48

Buda

Paris

Philadelphia

New York

St Malo

N antes •• •• •

Peking . ...

Milan *

•Ji
»

43 17
43 36
41 53
43 7
32 45
31 34

5 22E.
3 52E.
12 27E.
5 50E.
129 55E.
91 24w.

0
0
0
0
0
180

59.00
59.36
60.44
62.06
60.80
64.76

Natchez ....

68° to

72°.

32 37

36 48

16 56w.
3 IE,

0
0

68.54
69.98

]{*

30 2
19 11
23 10
10 27

30 18E.
96 Iw.
82 13w.
65 15w.

0
0
0
0

72.32
77.72

78.08
81.86

Vera Cruz «... . . . . ......

1'MJS ATMOSPHERE 159

CHAPTER V.

Optical Phenomena.

" Why do those cliffs of shadowy tint, appear
. More sweet than all the landscape smiling- near ?
'Tis distance lends enchantment to the view,
And robes the mountain in its azure hue."

CampbdL

IN the present chapter we shall describe and explain the general
optical appearance of the sky, and some of the more striking op-
tical phenomena connected with our present subject. When the
rays of the sun strike the minute particles of air, which, accord-
ing to circumstances, may be more or less dense, or charged with
watery vapor, they are either reflected, or transmitted ; in either
case some.times returning the most beautiful colors. It is a fact
to well known to need much illustration from us, that light, when-
ever it is refracted by any medium, such as glass or water, is al-
ways separated into the prismatic colors, whenever the surfaces
of the medium are curved, or inclined to each other. It is not
however, so generally understood, that these different colored
rays have different powers of penetrating through various media,
and that they move with different velocities. This however, is
susceptible of demonstration, and it is to this that the beautiful
colors of an autumnal sunset are owing. The red, violet and
orange rays have the greatest velocity, and penetrate the thick
dense strata of horizontal air, with the greatest facility, giving us
the rich and brilliant hues of sunset and sunrise, tinging the
morning and evening clouds with glowing red, and gold ; and
the sober twilight, with that purple fading into gray which is assum-
ed when the ruddy glare of sunset is tempered by the azure of
the sky. Since the red and yellow rays which compose white
light, are transmitted by the air, unattended by the blue rays, it
follows that these latter must be reflected, hence the beautiful

160 TH£ WOULD. /

blue of the sky, and the bright azure which tinges the distant
mountains when viewed through a considerable body of inter-
vening air, and especially, when charged with watery vapor
Perhaps this one feature., which so mellows down the distant out-
lines of the hills and buildings, is the most pleasing feature of
the landscape. It is from strict attention to the phenomena de-
pendent upon this principle, that the artist derives his pleasing
skill in picturing objects of varying distance, introducing skill-
fully the color of the intervening air. How simple, and yet how
beautiful are the various contrivances which administer, not to
the wants merely, but to the pleasures of man. It is the same
simple cause which tints the bright blue sky, and its beautiful
clouds, here piled in snowy masses, and there sundered into a
thousand fleecy shapes; which lights the west with a golden glow»
and fringes the extended clouds that skirt the horizon with the
brightest hues of red and gold ; and it is owing to the peculiar
nature of the red rays of the spectrum, that the sun appears a
dull red globe when viewed through air highly saturated with
watery vapor, or through clouds and fogs.

When the rays of the sun strike upon a cloud, they are copi-
ously reflected, but partly absorbed by the minute suspended glo-
bules, and the quantity of light which penetrates through the
nebulous medium is always much less than what traverses an
equal body of air, and this gives the clouds their varying shades
of color. That the color of the sky is owing to reflected light, is
sufficiently evident from the fact, that it becomes darker and
darker, as we ascend into the higher regions of the atmosphere,
through which, the blue rays find a ready passage. Were it not
for the reflecting power of the atmosphere, and the clouds, we
would have no softening of the day into night, as now, by the
twilight; but instantly, at sunset, darkness would veil the earth,
and every cloud that obscured the sun would cause a total eclipse.
The tint of the sky is deeper in the torrid zone than in high lati-
tudes, and in the same parallel it is fainter at sea than on land,
this may be attributed to the aqueous vap'or continually rising
towards the higher regions of the" air from the surface of the sea.
The presence of much moisture is also easily detected by the

HALOS. 161

paleness of the sun at sunset, by means of which, sailors are ac-
customed to presage a storm.

The colored rings or halos which are often seen surrounding
the sun and moon are evidently occasioned by very thin vapor
diffused through the atmosphere. They are supposed chiefly to
encircle the moon, but scarcely a day passes without light misty
clouds, when at least portions of halos may be seen near the sun,
and in order to perceive them, it is only necessary to remove
the glare of light which makes the delicate colors appear white.
Thus, if we examine the reflection from a smooth surface of wa-
ter, we will perceive that the sun gilds the fleecy clouds with seg-
ments of beautifully colored rings. This effect is more distinctly
seen, if the rays from a hazy or a mottled sky, be received upon a
sheet of white paper held before a small hole in the window shut-
ter in a dark room. But even when the sun shines from an azure
firmament, circles of the richest tints may be produced by experi-
ment, thus, holding a hot poker below, and a little before the small
hole in the shutter, above mentioned, throw, a few drops of wa-
ter upon it, and the sun will be painted upon the paper like the
glowing radiations of the passion flower.

Halos are produced by what is termed the diffraction of light,
i. e. the rays of light in passing near the edges of a body appear
to be bent from their rectilineal course. This diffraction maybe
easily observed by viewing objects through a minute hole, it will
be found that the edges of straight bodies will be curved if viewed
near the edge of the hole, and a line of bright white light, will
appear tinged with orange on the side nearest the edge of the
hole, and with blue upon the other. Halos are much more com-
mon in the northern latitudes than in warmer climates, a fact
which is owing doubtless, to frozen particles of water floating in
the air, though Humboldt remarks that lunar halos are much
rarer in the northern than the .southern countries of Europe, and
seen more especially when the sky is clear and weather settled.
He observes that in the torrid zone they appear almost every night,
and often in the spdke of a few minutes disappear several times.
Between the latitude of 15° N. and the equator, he has seen
small halos around the planet Venus. The next figure exhibits

1G2

THE WORLD.

a halo seen around the sun by Scheiner in 1530. In this fine set
of halos mock images of the sun at the intersection of the cir-
cles, termed parhelia and anthelia may be observed. These are

quite common in the arctic regions, presenting the gorgeous ap-
pearance of intersecting luminous arches, studded with opposite
and transverse images of the sun ; the formation of these, is
undoubtedly owing to the combined reflections of the rays from
the natural faces of the snowy crystals floating abundantly in the
air. Fringes of colored light, similar to those which form halos;
may be observed in looking through the fibres of a feather, or
thin streaks of grease rubbed over a glass plate. If a small hole
is made in a piece of tinfoil, and held close to the eye, a halo
will be seen upon looking at the sun through it, very near to his
disc. By comparing the artificial halos tmis formed with the
natural ones, Prof. Leslie endeavored to ascertain the size of the
globules producing the halos, it being inferred that an aqueous

1-63

•globule of the same dimensions as the perforation might produce
a similar halo. He found them to vary from the 5000th to the
.50,000th part of an inch in diameter. When the hale approach-
es nearest to the body, the largest globules are floating, and there-
fore the atmosphere is surcharged with humidity. Hence the
justness of the vulgar remark, that a dense halo close to the moou
portends rain.

The elevation of coasts, ships, and mountains, above their
•usual level has long been knewn under the name of looming,
and the name 'mirage has been given by the French to the same
^phenomena. The curious spectacle often witnessed at the straits
of Messina called the Fata-Morgana, belongs do the same class of
.optical phenomena. One of the most interesting cases on record
.was witnessed by Opt. Scoresby, in the Arctic sea. WhUe-nav-
jgating the Greenland sea on the .28th of June, 1820, he observed
about eighteen or nineteen sail of ships .at .the distance of from
<ien to fifteen miles. He saw them from the mast-head begin-
ning to change their form, one was drawn out or elongated in a
s/ertical plane, another was contracted in the same direction, one

fcad an inverted image immediately above it as at a; and two at h
and c, had two distinct inverted images in the air; along with
these images there appeared images of the ice, as at b and c, in
two strata, the highest of which had^n altitude of about fifteen de-
grees. In a later voyage performed in 1822, he saw his father's
«hip when below the horizon. *' It was" says he, " so well de-
X-n.ed that I could distinguish by a telescope every sail, the genera

rig of the ship, and its particular character, insomuch that I con-
fidently pronounced it to be my father's ship, the Fame, which it
afterwards proved to be, though in comparing notes with my fa-
ther, I found that our relative positions at the time gave our dis-
tance from one another very nearly thirty miles, being about-
seventeen miles beyond the horizon, and some leagues beyond
the limit of direct vision. 1 was so struck by the peculiarity of
the circumstance, that I mentioned it to the offiser. of the watch*,
stating my full conviction that the Fame was then cruising in i\\&
neighboring inlet."

A fine exhibition of mirage was witnessed at Cleveland on the
afternoon of April 12, 1848, at half past three o'clock, P. M.r
and which is represented in the engraving below. The steam-
boat New Orleans left Fairpart, 30 miles from Cleveland, at 3h
10m. P. M., and consequently at the time the mirage was seen,
was below the horizon ; with a glass however, two distinct ima-
ges were perceived elevated' in the air, and a point of land ordi-
narily invisible coi^d be easily observed. This phenome»on was*
witnessed by a large number oi persons.

These phenomena, which we Have repeatedly witnessed, are-
owing to peculiar states of the atmosphere as regards density and
moisture. Every one is aware that a straight stick appears to b<&
crooked when thrust iiito tne water, bending at the pis ne of the'
surface, and when a ray of light passes from one medium to an-
other this refraction or beading always occurs, in a greater or less
degree, according to the difference of density in the media, on
the peculiar refracting power. The effect oratmospherie refrac-
tion is always to make a body appear higher than it really is, thus
we see the sun, actually after sunset, the rays which proceed from

METEORIC SHOWERS. 165

it up into the sky, being BO bent downwards as to reach the eye.
Among the most beautiful phenomena that greet the eye when
contemplating the heavens in a serehe night, but more particu-
larly in autumn, the shooting stars, or meteors are preeminent; at
almost all seasons of the year an attentive observer will perceive
them moving swiftly over tho heavens, and occasionally leaving
a long luminous train behind. Their oi'igin has not been satis-
factorily traced, yet, since their occurrence in unusual numbers,
and splendor, is now proved to be periodical, it is supposed they
may be in some way connected with that beautiful luminous ap-
pearance called the zodiacal light. This is the opinion of Prof.
Olmsted, who has devoted much time to this subject, and has
been a careful investigator of the facts connected with meteors
and the zodiacal light for many years. The " falling stars" seem
to have been observed in the earliest times, and were considered
as a presage of violent winds, thus Virgil —

"And oft before tempestuous winds arise,
The seeming stars fell headlong from the skies,
And shooting through tho darkness, gild the night
With sweeping lines, and long trains of light."

The number of meteors visible at ordinary seasons of the year in
one night, is quite limited, but we must remember that many of
them are very small, and probably too distant to be observed by the
unassisted eye. We have often witnessed the passage of meteors
through the field of view of a night-glass when sweeping the
heavens for comets, and have occasionally seen some very beau-
tiful trains not at all visible to the unassisted eye.

In the year 1833 a most remarkable display of falling stars
was witnessed in the United States, but was not seen either in
South America or Europe. It occurred on the morning of Nov.
13th, and exceeded in magnificence any natural phenomenon we
have ever witnessed ; the whole heavens seemed glowing with
fire-balls, which were falling in all directions. For many suc-
cessive years this exhibition was repeated on the same morning,
occurring most abundantly at about 4 o'clock, and apparently ra-
diating from one centre, but each year their numbers diminished,
and we believe that now, no more are visible upon on that night

166 THE WORLD.

than Upon any other. Two other periods of unusual brilliancy
seem to have been pretty well determined, viz : April 21st, and
Aug. 10th. It is our opinion that these meteors, and the zodiacal
light, are both of terrestrial origin, L e. have their origin within
the limits of our atmosphere. The greatest height at which these
bodies occur is supposed to be about 2300 miles : at this height
the atmosphere would be excessively rare, but it is probable that
the upper strata are composed of more inflammable materials
than common air ; hydrogen gas is continually being emitted by
the great laboratory of nature, and ascends to the upper regions,
here, when released from pressure it may expand to at least the
distance, (and beyond it), where meteors occur. Sir John Les-
lie thus accounts for the lambent glow of the heavens in a clear
night, supposing this stratum of highly inflammable gas to be
phosporescent. We might perhaps trace the zodiacal light to the
same source. This remarkable appearance is most conspicuous

in the finer climates and near the vernal equinox, and has offpn
been ascribed to thp extension of a supposed luminous atmos-

LYGtTT. 1$7

phere about the sun. Laplace seems to have shown satisfactorily
that such an atmosphere, far from extending to the earth, would
not reach to even the orbit of Mercury- If this be so, we must
either adopt the theory of Von Humboldt, who supposes it to be 'a
luminous ring surrounding the sun, or conclude it is of terrestrial
origin. The preceding cut represents this beautiful phenom-
enon. It may he seen in our northern latitude in the spring months
after sunset, reaching up in the plane of the ecliptic towards the
Pleiades long after sunset; it gradually sets with the stars and may
again be seen in the morning before sunrise. According to Sir
John Leslie, the sun, shining upon the higher strata of the at-
mosphere, which he supposes phosphorescent, would form a large
luminous circle which we would see surrounding the sun at noon,
provided it was not eclipsed by his superior brilliancy; after sun-
set it would appear as a segment of a circle, did not the vapors of
the horizen obscure its extreme and faintest limits, hence it appears
lenticular, or lens shaped as represented in the engraving

We shall conclude this chapter with a description of that well
known, but yet unexplained phenomenon the Aurora Borealis or
northern lights. In the high northern latitudes, beautiful dis-
plays of the aurora are witnessed, and they serve to enliven the
long winter nights with their bright coruscations. In our latitude
the exhibitions are of a less beautiful character, and rarer, but vet
so frequent that they are familiar to all. It generally appears
like a bank, or cloud of light, of a pale yellow color, resting upon
the northern horizon, occasionally emitting streamers which shoot
up towards the zenith, and then fade, revive again, and subdivide.
At other times It is seen as a luminous arch rising a short dis-
tance above the horizon, its highest altitude being in the magnet-
ic meridian ; from this, streamers ascend, and if the display is a
fine one, will appear to unite in a circle nearly in the zenith, called
the corona. It is a remarkable fact that great displays of the
aurora are always proceeded bv a disturbance of the magnetic
needle. Like the meteoric showers, there seems to be a periodi-
cal return of the auroral displays in unusual splendor, after defi-
nite intervals. One of these returns, which we well remember,
occurred at intervals from November 1835, to May 18.36. The

IDS THE WORLD,

two following descriptions are from the pen of Professor OlrnsteeL
The first display took place on the 17th of November 1835, the
last on the 23d of April 1836.

*• On the 17th of November, 1835, our northern hemisphere
was adorned with a display of auroral lights remarkably grand
and diversified. It was observed at fifteen minutes before seven
o'clock, when an illumination of the whole northern sky, resem-
bling the break of day, was discernable through the openings in
the clouds. About eighteen degrees east of north, was a broad
column of shining vapor tinged with crimson, which appeared
and disappeared at intervals.. A westerly wind moved off the
clouds, rendering the sky nearly clear by eight o'clock, when two
broad, white columns, which had for some time been gathering
between the stars Aquila and Lyra on the west, and the Pleiades
and Aries on the east, united above, so as to complete a lumin-
ous arch, spanning the heavens a little south of the prime vertical.
The whole northern hemisphere, being more or less illuminated,
and separated from the southern by this zone, was thrown into
striking contrast with* the latter, which appeared of a dark slate
color, as though the stars were shining through a stratum of black
clouds. The zone moved slowly to the south until about nine
o'clock, "when it had reached the bright star in the Eagle in the
west, and extended a little south of the constellation Aries in the
east. From this time it began to recede northward, at nearly a
uniform rate, until twenty minutes before eleven, when a vast
number of columns, white and crimson, began to shoot up, sim-
ultaneously, from all parts of the northern hemisphere, directing
their course towards a point a few degrees south and east of the
zenith, around which they arranged themselves as around a com-
mon focus. The position of this point was between the Pleiades
and Alpha Arietis, and south of the Bee.

Soon after eleven o'clock, commenced a striking display of
those undulatory flashes denominated merry dancers. They con-
sisted of thin waves or sheets of light, coursing each other with;
immense speed. Those undulations which play upon the sui>
face of a field of rye, when gently agitated by the wind, may give
the reader a faint idea of these auroral waves. One of these

AURORA BOREALIS. 169

crimson columns, the most beautiful of all, as it ascended to-
wards the common focus crossed the planet Jupiter, then at an
altitude of thirty-six degrees. The appearance was peculiarly
interesting, as the planet shone through the crimson clouds with
its splendor apparently augmented rather than diminished.

A few shooting stars were seen at intervals, some of which
above the ordinary magnitude and brightness. One that came
from between the feet of the Great Bear, at eight minutes after
one o'clock, and fell apparently near to the earth, exhibited a very
white and dazzling light and as it exploded scattered shining frag-
ments very much after the manner of a sky rocket.

As early as seven o'clock, the magnetic needle began to show
unusual agitation, and after that it was carfully observed. Near
eleven o'clock, when the streamers were rising and the corona
forming, the disturbance of the needle was very remarkable,
causing a motion of one degree and five minutes, in five minutes
of time. This disturbance continued until ten o'clock the next
morning, the needle having traversed an entire range of one de-
gree and forty minutes, while its ordinary deflection is not more
than four minutes.

Another writer, speaking of the same appearance, says — We
can compare the spectacle to nothing but an immense umbrella
suspended from the heavens, the edges of which embraced more
than half the visible horizon ; in the south-east its lower edge
covered the belt of Orion, and farther to the left the planet Ju-
piter shone in all its magnificence and glory, as through a trans-
parency of gold and scarlet. The whole scene was indescribably
beautiful and solemn. It was a spectacle of which painting and
poetry united can give no adequate idea, and which philosophy
will fail to account for to the satisfaction of the student of nature,
or the disciple of revelation. The cause can be known only to
HIM at whose bidding

Darkness fled — Light shone,
And the etherial quintessence of heaven
Flew upward, spirited with various forms
That rolled orbicular, and turned to stars.

The appearance of April 23d 183G, is thus described by Olm-

170 THE WOULD.

sted : — Last night we were regaled with another exhibition of the
auroral lights, in some respects even more remarkable than that
of the 17th of November, It announced itself as early as a quar-
ter before eight o'clock, by a peculiar kind of vapor overspread-
ing the northern sky, resembling a thin fog, of the color of dull
yellow, slightly tinged with red. From a bank of the auroral
vapor that rose a few degrees above the northern horizon, a great
number of those luminous columns called streamers ascended to-
wards a common focus, situated, as usual, a little south and east
of the zenith, nearly or perhaps exactly at the magnetic pole of
the dipping-needle. Faint undulations played on the surface of
the streamers, affording sure prognostics of an unusual display of
this mvsterious phenomenon. The light of the rnoon, now near
its first quarter, impared the distinctness of the auroral lights, but
the firmament throughout exhibited one of its finest aspects. The
planet Venus was shining with great brilliancy in the west, fol-
lowed at small intervals by Jupiter and the moon; while the larger
constellations, Orion and Leo, with two stars of the first magni-
tude, Sirius and Procyon, added their attractions. The sky was
cloudless, and the air perfectly still.

There are but few examples on record of the auroral lights dip-
playing themselves with peculiar magnificence in moonlight.

Notwithstanding the presence of the moon, by half past ten
o'clock, the auroral arches, streamers, and waves began to exhibit
the most interesting appearances. No well-defined arch was
formed, but broad zones of silvery whiteness, composing greater
or less portions of arches, were seen in various parts of the heav-
ens. Two that lay in the south, crossing the meridian at differ-
ent altitudes, were especially observable. From each proceeded
streamers, all directed towards the common focus. At the same
lime, those peculiar undulations called merry dancers, were flow-
ing in broad and silvery sheets towards that point, writhing around
it in serpentine curves, and ofteu assuming the most fantastic
forms. The swiftness of their motions, which were generally
upward, and often with their broadest side foremost, was truly
astonishing. Toward the horizon the undulations were compara-
tively forhje; but from the elevation of nhout thirty degrees to

AURORA. BOREALIS. Itl

the zenith, their movement was performed in a time not exceeding
one second, — a velocity greater than we have ever noticed be-
fore, which was still distinctly progressive.

Five minutes after eleven o'clock, a few large streamers, of
the whiteness of burnished silver, radiated from the common
focus towards the east and the west. These were soon superse-
ded by a mass of crimson vapor, rising simultaneously a little
south of west, and north of east, and ascending1 towards the focus
in columns eight or ten degrees broad below, but tapering above;
these disappeared in about ten minutes, and the lights were sub-
sequently a pure white, except an occasional tinge of red. During
the appearance of the crimson columns a rosy hue was reflected
from white houses and other favorable surfaces, imparting -to
them an aspect peculiarly attractive.

From this time until half past two o'clock, our attention was
almost wholly absorbed in contemplating the sublime movements
of the auroral waves : they evidently were formations entirely
distinct from the columns, which either remained stationary, or
shot out a broad stream of white light towards the focus, while
the waves apparently occupied a region far below them.

At half past two o'clock, a covering of light clouds was spread

over a large portion or the sky, and our observations were dis-

172

THE WORLD.

continued. At this time, although the moon was down, yet its
absence produced little change in the general illumination ; the
landscape appeared still as if enlightened by the moon, and it
was easy to discern the time of night by a watch, from the light
of the aurora." •

On the preceding page, is a view of the Aurora as witnessed by
the French philosophers in the year 1838 — 9, at Borekop, bay of
Alten, coast of W. Finmark, lat.70° N. It presented the form of a
scroll with folds overlapping, and waving like a flag agitated by the
wind. Its brightness varied very suddenly, and the colors changed
from bright red at the base, to green in the middle portions, and
yellow at the top. The brightness would diminish, and colors
fade, sometimes suddenly, and sometimes by slow degrees. After
this, the fragments would be gathered, and the folds reproduced;
the beams seemed to converge at the zenith which was doubtless,
the effect of perspective.

But it is in the Arctic regions that this phenomenon is witnessed
in its greatest splendor, and presenting a variety of the most
beautiful tints. In that cold region, clouds seldom obscure the
sky, nothing in the form of fog or mist veils the deep blue of the

AURORA BOREALIS. 173?

heavens, every star blazes forth like a diamond, and a thousands
icy pinnacles throw back their light, accompanied with magnifi-
cent prismatic displays. The bold hunters who penetrate the-
arctic circle in the pursuit of the silver fox and the sable, witness
its grandest exhibitions. The whole sky is lighted up with thej
bright coruscations, and it is said that a rushing sound, like that
of winds sweeping over a distant forest is heard. The inhabit-
ants of the Shetland island's call the streamers merry dancers.

The appearance of the aurora, and the emotions it excites, are1
thus beautifully described by Whittier:

A light is troubling Heaven ! A strange, dull glow
Hangs like a half-quench'd veil of fire between
The blue sky and the earth ; and the shorn stars
Gleam faint and sickly through it. Day hath left
No token of its parting, and the blush
With which it welcom'dthe embrace of Night,
Has faded from the blue cheek of the West ;
Yet from the solemn darkness of the North,
" Stretch'd o'er the empty place** by God's own hand,.
Trembles and wave.s that curtain of j>tile fire,
Tinging with baleful and unnatural hues
The winter snows beneath. It is as if
Nature's last curse — the fearful plague of fire,
Were working in the elements, and the skies
Even, as a scroll consuming./

Lo, a change !

The fiery wonder sinks, and all along
The dim horizon of the clouded North
A dark, deep crimson, rests a sea of blood-
Untroubled by a wave. And over all
Bendeth a luminous arch of pale, pure white,.
Clearly contrasted with the blue above,
And the dark red beneath it. Glorious !
How like a pathway of the Shin-ing Ones,
The pure and beautiful intelligences
Who minister in Heaven, and offer up
Their praise as incense ; — or like that which rosa-
Before the pilgrim Prophet, when the tread
Of the most holy angels brighten'd it,
And in his dream the haunted sleeper saw
The ascending and descending of the blest !

And yet another change ! O'er half the sky »

A long, bright rlame is trembling like the sworcS
Of the great angel at the guarded gate

174 THE WORt.D.

Of Paradise, when all the holy streams
And beautiful bowers of Eden laud -blush'd red
Beneath its awful waving1, and the eyes
Of the lane outcasts quailed before its glare,
As from the immediate questioning of God.

And men are gazing to these " signs in Heaven"
With most unwonted earnestness ; and fair
And beautiful brows are redd'ning in the light
Of this strange vision of the upper air :
Even as the dwellers of Jerusalem,
Beleaguer'd. by the Roman, — when the skies
Of Palestine were thronged with fiery shapes,
And from Antonia's tower the mailed Jew
Saw his own image pictured in the air
Contending with the heathen ; and the priest
Beside the temple's altar veiled his face
From that fire -written language of the sky.

Oh, God of mystery I these fires are thine !
Thy breath hath kindled them, and there they burn.
Amid the permanent glory of Thy heavens,
That earliest revelation, written out
In starry languaget visible to all,
Lifting unto Thyself the heavy eyes
Of the down looking spirits of the earth !
The Indian leaning on his hunting bow,
Where the ice mountains hem the frozen poJe,
And the hoar architect of Winter piles
With tireless hand his snowy pyramids,
Looks upward in deep awe — while all around
The eternal ices kindle with the hues
Which tremble on their gleaming pinnacles,
And sharp, cold ridges of enduring frost, —
And points his child to the Great Spirit's fire.

Alas ! for us who boast of deeper lore,
If, in the maze of our vague theories,
Our speculations, and our restless aim
To search the secret, and familiarise
The awful things of nature, we forget
Ttf own Thy presence in Thy mysteries !

THE WORLD

PART III,

PHYSICAL STRUCTURE OF THE EARTH,

CHAPTER 1.

Structure of tlie Earth.

" Ye mighty ones who sway the souls that go
Arnid the marvels of the world below!
Ye, silent shades, who sit and hear around !
Chaos! and streams that burn beneath the ground!
All, all forgive, if by your converse stirred,
My lips shall utter what my ears have heard;
If I shall speak of things of doubtful birth,
Deep sunk in darkness, as deep sunk in earth."

Virgil,

WE have before shown that our globe is a planetary orb of a
few thousand miles in diameter, and of a spheroidal shape, the
difference between the polar, and equatorial diameters being
twenty-six miles. The mean density of the earth, is about five
times that of water, the interior being double that of the solid su-
perficial crust, hence if the interior of the earth be cavernous,
its crust must be composed of very dense materials. The crust,
or outer covering of the earth, significantly called " Erdrinde,"
or Earth-rind, by the Germans, is that part to which our investi-
gations are naturally directed. The greatest thickness of this su-
perficial crust, which man has been able to explore, estimated
from the highest mountain peaks, to the greatest natural or arti-
ficial depths, does not exceed ten miles ; this, in comparison with
the diameter, 8000 miles, is a distance, utterly insignificant, bear-

THE WORLD.

178

ing about the same relative proportion, as the thickness of this pa-
per to an artificial sphere a foot in diameter. The inequalities
and crevices in the varnish of such a sphere, would proportion-
ately represent the highest mountains, and deepest valleys. In
the following diagram, frdm the Penny Cyclopedia, the relative
proportions of the crust of the earth, and the inequalities of its
surface, as compared with the mass of our planet, are attempted
to be shown.

The line from c to k, represents a depth of 500 miles, to the
point i, a depth of 100 miles, and to the line b, 45 miles above
the surface, the supposed limit of the earth's atmosphere. The
dark line represents a thickness of ten miles, the estimated thick-
ness of the crust of the earth ; the points d e f g, indicate the
altitudes of the highest mountains in the world. The highest
peak in Europe, being Mont Blanc, which is 15,660 feet above
the level of the sea ; and in America, Mount Sorata, Andes, 25,-
400 feet, and in Asia, Chumularee, Himalayah, estimated at 29,-
000 feet, being more than five miles of perpendicular altitude.
The depth of the sea is shown by the line a h, at the extremity
of the arc. When we consider that the altitude of the highest
mountains bears so small a proportion to the probable thickness
of the earth's crust, we will be prepared to admit the possibility
that they might once have been the bed of the ocean, and may
hare been raised to their present situations by subterranean
agency,

OF SURFACE. 179

The external crust, or covering of the earth, is composed of a
vast amount of substances which we shall more fully describe
hereafter, but which, under the indefinite but convenient terms
of rocks and earth, embracing every variety of element, and
combination, are familiar to every one.- Although of such mi-
croscopic value as regards the dimensions of the globe itself, yet
the crust upon which we are located, is of infinite importance to
man. With its alternations of land and water,- of valleys and
mountains, it is the seat of vast empires, and the storehouse of
the wealth of nations. The surface of the earth has been com-
puted to contain one hundred and fifty millions of square miles,
about three-fourths of which are covered by seas, and another
large proportion by bodies of fresh water, by polar ice, and eter-
nal snows ; so that, taking into the estimate the sterile tracts, the
forests, the barren mountains, the bogs, morasses, &c<, scarcely
more than one-fifth of the globe is fit for the habitation of man.
The area of the Pacific ocean alone, is estimated as equal to the
whole surface of the dry land, hence, if the waters of the globe
were uniformly distributed over its surface, the inequalities being
leveled, the whole earth would be covered with water to a depth
of about three feet. The presont arrangement of continents and
islands cannot therefore be supposed to have always existed, in-
deed, there is abundant evidence to show that all those parts,
which we call dry land, have at some very remote period been
underwater, and that the soil upon which we now tread, is com-
posed of regular strata, deposited by water. It is but a short period
since the utmost ignorance prevailed as to the structure of the
planet which we inhabit. It was accustomed to be looked upon
as a mass of confusion, the chaos of old, where, in incongruous
masses, were heaped the various substances of which it was
composed, and where antagonistic forces were striving confusedly
together.

It was true that rocks were found at some places upon the sur-
face, and not at others, but this was regarded as mere matter of
chance, no one supposed any order, or any definite arrangement.
It was reserved for modern science to show that the crust of the
earth from its surface downwards, is composed of regular Btra-

%80 THK WORW>.

ta, always succeeding in the same order wherever examined, and
each formation marking a distinct epoch in the history of our
planet; each characterized by its own flora and fanna, so that the
whole substance which has hitherto been explored, consists of
either minerals, i. e. inorganic substances formed by natural ope-
rations, or die fossil remains of animals and vegetables, charac-
terizing peculiar and distinct epochs in the history of the globe.
" The arrangement of the various formations may be represented
l)y an alphabetical series from a to z, and this order, though it is
frequently imperfect, is never inverted, We often miss one, or
*nore, terms in the series, and lose, say the -b or /* or m, or even
several letters in succession, but we never find the b taking the
.place of the a, or d preceding the c, or any member of the series
usurping the position of another which ought to go before it ; in
other terms, we never meet with the entire series of deposits, but
-those which do occur invariably follow in a regular order of 86^
<juence."

We have said 'that these strata are all either mineral or fossil.
Kemotely they all are of mineral origin, for all organic substances
have been at some time elaborated from inorganic matter by that
marvelous principle termed vitality. There are fourteen simple
substances which are named below in order, according to their
importance, which constitute the chief part of the earth's sur-
face. The first eight are called simple Non-Metallic substances*

1. Oxygen, 5. Sulphur,

2. Hydrogen, 6. Chlorine,

3. Nitrogen, 7. Fluorine,

4. Carbon, 8. Phosphorus.

These eight simple substances by their union with certain metals,
which are hence called metallic bases, and also by union with
each other, form by far the greatest amount of all the matter, or-
ganic, or inorganic, solid, or liquid, or gasseous," which is known
to exist on the surface of the earth. The metallic bases alluded
to are

1. Silicium, 4. Sodium,

2. Aluminium, 5. Magnesium,

3. Potassium, 6. Calcium.

We cannot here describe each of these elementary bodies, this

MINERALS, 181

Will be found in most treatises upon chemistry; suffice it that a
union of silicmm and oxygen forms nearly one half the solid part
of the earth's crust, being a chief ingredient in all the principal
rocks. It appears nearly pure in the state of transparent rock
crystal, and is the chief ingredient of our ordinary flints and
sands. Aluminium in combination with oxygen, is the base of
the various clays and clayey slates. Potassium in combination
with oxygen, and also sodium with oxygen, constitute very im-
portant ingredients of the rocks and earths under the well known
forms of potash and soda, and the latter in combination with
chlorine forms muriate of soda or common salt, so. widely preva-
lent in the ocean, and in beds of rock salt. Magnesium i^. the
base of manganese a chief ingredient of the chalks, and magne-
sias limestones; and calcium is the metallic base of lime, and is
found in abundance in the various limestones and gypsnms. Be-
sides the simple substances named, we have the metallic miner*
als, which are usually found in beds or veins. The most of these
are so well known that they are recognised at a glance. Iron is
the most useful and most abundant, when combined with sulphur
it crystalises in cubes, is of a bright yellow, and is often mista-
ken for gold; this variety is termed iron pyrites. Iron is likewise
found in combination with oxygen and carbon, and occasionally
nearly pure. Lead is a well known metal occurring principally
in union with sulphur, under the form called galena, in cubic
crystals. Copper is found in combination with oxygen and sul-
phur, and also native, or pure ; in combination with carbon and
oxygen it assumes beautiful tints of blue and green. Tin, zinc,
and manganese are too well known to need any particular descrip-
tion here. It is said that tin is only found in the primitive or
lowest order of rocks, and that the tin mines of Comwall^xtend
many hundred feet under the sea, and that the noise of the waves
and the rolling of the pebbles can be distinctly heard. We need
not describe the precious metals, silver, gold, and platina, as
everybody is familiar with their general properties. The various
stibstances which form the crust of the earth, and which have
been investigated by the persevering energy of man, are arranged
into two great classes, which embrace all the various soils, sands,

182 THE WORLD,

gravels, clays, limestones, coals, slates, and granites ; these t\v£
classed, are the stratified, and unstratificd rocks. In the former,
are included those portions of the crust of the earth which ex-
hibit a sedimentary character, i. e., evidence of deposition through
the agency of water. It is supposed that all rocks were once de-
posited in this manner, but that the present crystaline form of
some of them is owing to heat, hence the tmstratified, are some-
times termed the igneous or the phitonic rocks; and the strata
which happen to intervene between them, being partly changed
in their character, yet not wholly so, are termed the metamorphic,
or transformed rocks; and those rocks resembling lavas scoriae,
and other substances, emitted by burning mountains, still in ac-
tivity", are called volcanic. When we assume that all the igneous
or plutonic rocks, such as granite, sienite, and the like, are of
sedimentary origin, we speak hypothetically, they are supposed
to be so ; for rocks, which are well known to present evidence of
aqueous origin, become crystaline, and lose the marks of stratifi-
cation under pressure, and by the influence of heat ; thus, chalk
has been converted into marble. Sir James Hall, exposed pound-
ed chalk to intense heat, under great pressure, and it was fused*
not into lime, but into crystaline marble ; even the shells inclosed
in the chalk underwent the same transmutation, yet preserved
their forms; and where ancient streams of lava have traversed
chalk, the latter invariably possesses a crystaline structure, and a
series of changes from a loose earthy deposit, to compact volcanic
lava, may be traced in numerous instances, so as to leave nd
doubt of the former aqueous origin, and the sedimentary deposit.

The crystaline rocks, such as granite, sienite, porphyry, ser-
pentine, and greenstone, are generally termed the ancient or
earliest rocks, as they are uniformly found underlying all the
other strata ; they were hence, named hypo gent, under-lying, by
Mr. Lyell. It is now however, ascertained that they belong to no
particular age or epoch, exclusively ; for granite is found occur-
ring at comparatively modern, as well as ancient epochs, over-
laying the other strata precisely in the same manner as masses
of volcanic rock recently ejected, spread out upon the soil below.
The difference in character between the modern lavas, and

STRATIFIED 110CRS*

183

the lower igneous rocks, is doubtless to be attributed to their for-
mation upon the surface, instead of under pressure. The term
hypogene includes the plutonic, and metamorphic rocks.

The sedimentary rocks are termed fossiliferous, or fossil-bear-
ing, in distinction to the igneous, or plutonic rocks, in which, by
the action of heat, all fossil remains are wanting. The stratified
rocks were originally deposited in a horizontal position as repre-
sented in this engraving, but they are rarely seen perfectly hori-

zontal, hence, it is inferred, that subsequently to their deposition*
they have been subjected to a variety of disturbing causes, by
which they have been made to assume all inclinations to the
horizon. Occasionally they are uplifted to an almost vertical po-
sition, as in the following illustration, exhibiting the strata on
which Powis Castle is built; when by being thus upheaved, the

edges of the strata are denuded, or uncovered, they are said to
crop out, when this occurs, it will be found that the strata suc-
ceed each other in regular order, as we have already mentioned.
When strata crop out, it is apparent, that having been elevated by

184

THE WORt.C.

some internal agency, the various formations, or beds of nearly
the same character, will OCCUP in contrary Order, thus, suppose
that by an upheaving cause, a series of strata, fig. 1, lying orig-

inally horizontal, as deposited at successive epochs, by water, to
be, by some internal force, upheaved as in fig. 2, the external

surface being rent and cracked, and further that after a course of
ages, the softer and more modern deposits should be worn away
by the agency of rains, frosts, floods, &c., until it was reduced to
the level a b, we would have the succession of strata as in fig. 3,

the harder rocks, perhaps of granite, forming a nucleus, or cen-
tre, around which the rest would lie in order; perfectly circular if
the elevation had been a true mound, or arranged in lines parallel,
or curved, according to the nature of the original elevation, and
if the elevation and subsequent denudation, had occured at a very
remote period, the whole might be covered with a light loose soil.
A very pretty and instructive example is shown in the diagram
on the next page, which is an outline map of Michigan.

Here the centre of the state is occupied by the coal measures
or formation, shown by the shaded portions, skirting this i a nar-
row stratum of limestone, beyond this and circling around it, is a

SUCCESSION OF STRATA.

185

wide stratum of the sandstone formation, followed by a fo:mation
of marine limestone and shales and slate. It is by observations

thus made near, or upon the surface, and carefully compared by
means of the fossils which are found imbeded in them, that ge-
ologists classify the various groups in the order we shall presently
name, and, as each stratum is characterized by its peculiar fossils,
and is never found taking the precedence of another which may
be anywhere found before it, they are justly supposed to be the
productions of different epochs. Thus, at one period of the earth's
history, peculiar limestones, sandstones, marls, and clays, were
deposited over the whole globe, upon those portions covered by
water; in which the zoophytes, fishes, drifted wood, plants, rep-
tiles &c., characteristic of that epoch were imbedded. At an-
other and previous period, were deposited the shales, the mill-
stone grit, and the immense beds of coal, imbedding peculiar and
distinct remains of animals and vegetables characteristic of that
epoch. At a still earlier period we find other distinct sedimentary
rocks, and under the whole, although sometimes appearing on the

186 THK WORLD.

surface, by being upheaved and uncovered, are found the crysta-
line masses of granite, porphyry, and sienite. Above all these
well marked sedimentary, or water deposits, lies a vast accumu-
lation of what is termed drift, being water worn, transported ma-
terials, consisting of the ruins of older rocks, and forming our
light covering soil, sometimes scarcely overlaying, and at others
of many feet in thickness, principally sand, clay, and gravel, and
large masses" of water worn or rounded stones, called boulders.
The more recent deposit'of this sort is called Alluvium, and in it
are imbedded the remains of man and his works, and such is the
character of the fluviatile or river deposits now going on, and to
which we" shall again allude. The older deposit is termed Dilu-
vium, and is found to contain no traces of man«or his works, but
in it are imbededthe remains of huge animals and reptiles now
extinct, and also with them the bones of many existing species of
animals, and the fossil remains of many known species of plants
are found. In the following chapter we shall endeavor to give a
clear view of the succession of the various strata and a short de-
scription of each, which shall be intelligible to any one who may
feel enough interested to read it, and in concluding this chapter
we must be allowed to say, that if the present part of our work
does not interest the reader, the book may as well be closed ; we
can learn him nothing, for there is no sympathy between us.

^CHRONOLOGICAL ARRANGEMENT OF STRATA.. 187

CHAPTER II.

t

ChrouQlogical Arrangement of Strata.

** What once had beejv the solid earth, I saw
To be a strait ; and from the waves new lands
Arose. Far off from the resounding sea,
The shells were strown about." Ovid.

»

ALTHOUGH geologists are perfectly agreed as to the order of suc-
tfsssion of the various strata, yet they have different methods of
expressing the same fact »In ether words, the names which are
used to designate the different formations vary somewhat, but in
the great leading features all are agreed. Thus, it matters little,
whether, after having divided all rocks into two great classes,
fossiliferous, and non-fessiliferous or meiaraorphic, we subdivide
ithe former with Dr. Bucklaad, into alluvium, diluvium, tertiary,
and the secondary or transition series; or with Dr. Mantell, into
modern and ancient alluvium, tertiary strata, and secondary for-
jnations; both include the same classes of rocks; or whether we
game a certain order of rocks the saliferous strata, or the upper
and lower red sandstone; both mean the same thing. The classi-
fication which we have adopted is principally that of Dr. Man-
tell, who gives the following as the chronological arrangement of
the strata, commencing with the uppermost or newest deposits.

I. FOSSILIFEROUS STRATA.

1. MODERN AND ANCIENT ALLUVIUM. — Comprising the modern
and superficial deposits of waterworn and transported materials,
sometimes called drift, and consisting of gravel, boulders, sand,
%clay, &c. The modern deposits are characterized by the remains
«f man, and contemporaneous animals and plants. The ancient,
sometimes called Diluvium, by an immense proportion of large

188 THE WOKLEV

mammalia and carnivora< of species and genera, both recent anej'
extinct.

2. THE TERTIARY SYSTEM. — An extensive series comprising
many isolated groups of marine, and laccistrine, or lake formed
deposits, characterized by the remains af animals and vegetables,,
the greater portion of which are extinct. Volcaaoes of great ex-
tent were in activity during this epech. Mr. Lyell subdivides
this series irfto the pliocene, or more recent; the wiocene, less re-
cent; and the eocene, dawn of recent; according to ehe percentage
of recent shells contained in each.

Secondary Formations*

3. THE CHALK OR CRETACEOUS SYSTEM. — A marine formation ^
being the bed of an ancient sea, comprising limestones, sand-
stones, marls, and clays, and abounding in the remains of zoophy-
tes, molusca, cephalapoda, fishes &c* drifted wood, and marine
plants, with crocodiles, turtles and other, now extinct reptiles,,
also birds.

The chalk formation embraces several beds or distinct strata,
thus, we have the upper chalk with flints, and the lower without;
the chalk marl, the firestone, the gait or stiff blue, or black clay,
abounding in shells, the shankHn or green sand.

4. THE WEALDEN. — From the German icald, a wood., th.®
whole tract so called in England having been once a dense foresL
This formation is the only known secondary fluviatile, or river
formed deposit. It is a fresh water formation, evidently the de- '
posit of some enormous ancient rivers, its fossil remains being
the spoils of river and land, it is characterized by the remains of
enormous and peculiar reptiles, namely the iguanodon, hylaeosa-
rus, megalosaurus, plesiosaurus, crocodile, turtle, &c.; of ter-
restrial plants, fsesh water shell-fish, and birds. The group
called the Wealden is composed of beds of stiff blue clay, with
beds of shelly limestone, called Sussex marble, beds of sands and
sandstones as found at Hastings in England, and the clays, sand-
stones, and shelly limestones, as found in the Isle of Purbeck,
called Purbeck marble,

SUCCESSION OF STRATA. 189

5. THE OOLITE. — This is a marine formation of vast extent
and thickness, its name means egg stone, because, it is formed
of small egg like grains. It consists of limestones and clays,
which abound in marine shells, corals, fishes; reptiles, both ter-
restrial and marine; land plants of peculiar species, and the re-
mains of two or more genera of marsupial animals, are likewise
found in it.

6. THE LIAS. — This name is supposed to be a provincial cor-
ruption of the word layers, as it consists of shale, or indurated
slaty clay, which splits into layers, alternating with clays and
limestones, containing marine shells, cephalapoda, crinoidea and
fishes. It is chiefly remarkable however, for its remains of
enormous reptiles particularly the plesiosaurus and the ichthyos-
aurus. The Lias group consists of the upper lias shale, mixed
with the lower oolite, containing saurian remains, belemnites and
ammonites ; the lias marls; calcareous, sandy, and ferruginous;
the lower lias clay and shales intercalated with sands and sep-
taria, and lastly a series of laminated limestones, with partings of
clay, which change into vast beds of red marl and sandstone
forming,

7. THE SALIFEROUS, OR NEW RED SANDSTONE SYSTEM. — A
marine formation comprising variegated marls and sandstones,
and conglomerates, frequently of a red color. The name new is
given to distinguish it from a formation of the same mineralogical
character but much older.- This series of deposits is remarkable
for the traces or footsteps of marsupial animals and birds, and
contains fossil remains of marine and terrestrial plants, fishes and
reptiles. This series forms the grand depository of rock-salt and
Jime, hence called the saliferous, salt bearing. Its variegated
color is owing to oxide of iron. The series consists of the upper
new red sandstone, containing gypsum and rock salt, with varie-
gated red and white sandstones, conglomerates or detritus qf
older rocks cemented together, and the lower new red sandstone,

Consisting of magnesian limestones called dolomite, and marls
and conglomerates colored with oxide of iron. This series rests
upon,

i*

190 THE WORLD.

8. THE CARBONIFEROUS, OR COAL SYSTEM, which is formed of
sandstones, grits, shales, layers of ironstone, and clay ; with
immense beds of coal; fresh water limestone sparingly, and ma-
rine limestone abundantly. This system is characterized by in-
numerable remains of land and aquatic plants, of a tropical char-
acter, and belonging to extinct species and genera, with fishes,
reptiles, and insects. The series includes the coal measures,
which are sandstone, and shale, with numerous layers of coal,
containing land plants in profusion. Limestones, with fresh water
and marine shells, Millstone grit, which consists of sandstone
and shale, with thin seams of coal, and quartose conglomerates
sometimes used for millstones. The carboniferous or mountain
limestone, consisting of limestone and flagstone, abounding in
crinoidea, and marine shells, yielding several varieties of black,
blueish grey, and variegated marbles. The coal bearing strata of
this country differ some from the European. The seams of coal
appear however, even in Europe, to be very unequally distributed;
although the great coal formation belongs in the order where we
have placed it, yet seams of anthracite coal are found in almost
every rock from the lias, to the upper metamorphic rocks, show-
ing that the coal beds have occurred at very unequal intervals,
hence their formation may be of any date between the new and
the old red sandstone.

9. THE DEVONIAN, OR OLD RED SANDSTONE SYSTEM. — This
name is derived from the English locality, where it is most large-
ly developed, viz : Devonshire. It is a marine deposit, chiefly
remarkable for its extraordinary forms of fossil fish. This sys-
tem is composed of various strata, flagstones, conglomerates,
quartose grits, sandstones, marls, and limestones ; the prevailing
color of all these is a dark red. But few fossils are found in the
sandstone and conglomerates, but in the marls, and concretionary
limestones, sometimes called corn-stones, peculiar genera of fish,
and many species of marine shells are found. This system lies
immediately below the mountain limestone. The sandstones are
in various stages of induration, and when slaty are employed fot
roofing. The red color is derived from peroxide of iron. The
formation of these rocks, has manifost.lv resulted from the \va*te

SUCCESSION OF STRATA. 191

of s!ate rocks, their detritus being cemented together by red sand,
or marl, into coarse conglomerates.

Primary Fossiliferous Period.

10. THE SILURIAN SYSTEM. — This name is derived from silures,
the name of the ancient Britons who inhabited that part of Eng-
land where it is most developed, viz : the border counties of
England and Wales, and south Wales. It is a marine deposit of
vast extent and importance, containing a great abundance of or-
ganic remains- It is principally composed of marine limestone,
shales, sandstones, and calcareous flags, abounding in shells,
corals, trilobites, and crinoidea of peculiar types; but few vegeta-\
ble remains are found below the old red sandstone.

11. THE CAMBRIAN, OR GRAUWACKE SYSTEM. — Grauwacke is
a coarse slaty rock, containing fragments of other rocks, some-
times passing into the common clay slate, and sometimes, when
the fragments are very numerous and small, into sandstones and
grits; it contains a few shells and corals, and occasionally im-
pressions of fuci; with this system all traces of organic remains
disappear. The fineness of grain, general aspect, and character
of these rocks, are well known from the universal employment
of slate for economic purposes.

II. HYPOGENE OR METAMORPHIC ROCKS.

Destitute of Organic Remains.

STRATIFIED.

12. THE MICA SCHIST. — This formation is supposed from cer-
tain traces of stratification, to have been sedimentary in its origin,
but subsequently altered by the influence of heat. It consists of
mica slate, granite rock, crystaline limestone, or white marble,
and hornblende schist, exhibiting no traces of organic remains.

13. THE GNEISS SYSTEM. — Layers of gneiss, sienite, and quartz
rock, alternating with clay slate, and mica schist, but still exhib-
iting marks of former stratification.

UN8TRATIFIEU.

14. GRANITIC SYSTEM.-— Consisting of porphyry, serpentine,
and trap rock in shapeless masses, and in dykes and veins.

192 THE WORL3>,

15. VOLCANIC BOCKS. — These are the products of fire, or sub-
terraneous heat, ejected from beneath the surface, through fis-
sures in the earth's crust, both in ancient and modern times ~
The erupted materials of the ancient ^volcanoes being trap, basalt,
loadstone and tuff, and the products of recent sub-aerial volcanoes,
lava, scoriae,, pumice and ashes.

The general proportionate thickness of each of these several
deposits has been estimated as under, but the statement must be
regarded as a men.' approximation.

Tertiary System, ....,..., 2,000 feet.

Cretaceous, 1,000 •*

Weald ...1,000 "

Oolite and Lias, 2,500

Saliferous, 2,000

Carboniferous, 10,000

Old Red Sandstone 10,000

Silurian, 7,500

Cambrian, 30,000

Mica Schist, and Gneiss, not ascertained, but far exceeding that
of any of the superposed deposits.

We have now given a connected view of the order of suc-
cession of the several strata, each characterised by its peculiar
animals and plants. All these are marine deposits except-one,
the fourth, called the Wealden. This is a fresh water formation,
and is the deposit of a mighty ancient river, or of several of them,
and its organic remains are such as might be expected to result
from the sediment of such a river, consisting of plants, shells,
fish, and reptiles, imbedded in the mud together. It is almost
the only evidence which remains of the ancient land, showing
that while the immense deposits were going on in the bed of
the ocean, here were bodies of fresh water, rolling over a vast
extent of land, bearing upon their waters the remain's of trees,
and huge reptiles. In the following chapters we shall consider
each of these formations more fully, and describe more particu-
larly some of the fossils found in them. It will be observed by
the careful reader, that most of the marine deposits of the several
epochs have the same mineralogical character: if we except the
coal, we will find the rest alternating with marls, clays, lime-
stones, and sandstones ; each being formed from the ruins of

GEOLOGICAL NOMENCLATURE. 193

more ancient formations, and each, imbedding1 in its sediment
the characteristic shells, fishes, reptiles, and plants, which were
either washed into, or once lived in the ancient sea, of which it
formed the bed.

The names which have been given to the different geological
formations must be received with some caution, for they are not
always indicative of formations identical with those from which
the name was derived. Many of these names are borrowed from
place^ thus, we read of the Jura limestone, the Kimmeredge
clay, Oxford clay, Purbeck marble, Portland rock, and Potsdam
sandstone. These names, referring to the stratum of a known
locality, were good so far as "an identity with that stratum can
be traced, but from the nature of the case, this is often incom-
pletely done, and hence the names necessarily cease to be defi-
nite. Many of the English provincial names are still retained,
though .very uncouth and harsh sounding, thus Geologists often
employ the terms Cornbrash, Lias, Gault, Coral Rag, and many
others which have no systematic signification.

Descriptive names applied in Geology are also defective, and
when employed, no scrupulous regard must be had to their appro-
priateness. " The Green Sand may be white, brown, or red ;
the Mountain Limestone may occur only in valleys ; the Oolite
may have no roe-like structure ; and yet these may be excellent
geological names, if they be applied to formations, geologically
identical with those which the phrases originally designated."
The term Oolite is an instance where a descriptive word has be-
come permanent, and in like manner the term proposed by Mr.
Murchison, for the transition series of rocks, which, from being
distinctly marked in South Wales, he calls Silurian, from th$
name of the ancient inhabitants, is in many respects excellent,
The terms employed by Mr. Lyell, before mentioned, as divisions
of the Tertiary formation, viz : Pliocene, Miocene, and Eocene,
according to the percentage of recent shells, being founded upon
a more natural'distinction will undoubtedly come into general use,
but even these are to be used with caution, and not allowed to set
aside the indications drawn from the natural relations of the strata.

194

THE WORLD.

CHRONOLOGICAL ARRANGEMENT OF STRATA. 195

EXPLANATION.

Ideal section of the crust of the earth, showing the chronologi-
cal arrangement of the strata.
M— Mantell.
B— Buckland.
L— Lyell.

1. Alluvial or modern deposits, a. 2. do. do. Overlaying the coal

2. Tertiary formations. formation.

3. Cretaceous system, compris- b. 1. Granite veins in Granite,
ing the chalk, with & with- b. 2. do. do. passing through por-
out flints, chalk marl, gait pi lyry, gneiss, & mica schist,
or blue clay, Shanklin sand. b. 3. do. do. Overlaying Grau-

4. TheWealden. wacke.

5. The Oolite. c. Dyke of Trap, passing thro'

6. The Lias. grauwacke and the lamina-

7. The Saliferous, consisting of tions of marine limestones,
New Red Sandstone, Mag- forming basaltic columns,
nesian Limestone. c. 1. do. do. intersecting, and

8. The Carboniferous System, overlaying an older dyke of
namely, the Coal measures, porphyry.

the Mo.untain limestone. c. 2. do. do. overlaying the oolite

9. The Devonian, or Old Red system.

Sandstone. <c. 3. do. do. overlaying the chalk

10. The Silurian, consisting of being lava of the extinct
marine limestones, shales, volcanoes of the Tertiary
calcareous flags. period.

11. The Cambrian. d. Modern lava.

*

12. Mica Schist. , e. Cave in magnesian limestone.

13. The Gneiss. f. Metallic veins in granite.

14. Granitic System. g. Extinct volcano.

15. Volcanic Rock. h. Artesian well.

a. 1. Dyke of Porphyry in gran-
ite, passing through & over-
laying gneiss.

196

THE WORLD.

The order of succession which we have" given has been de-
termined by a series of the most patient investigations, and from
an immense accumulation of facts, collected by able observers in
all parts of the globe. On page 194 we have given a diagram
showing their order. It will be perceived that some parts of the
representation are necessarily exaggerated. Commencing at the
left we have the hypogene, or underlying rocks, unstratified and
stratified ; then the primary and secondary fossiliferous, and also
the tertiary, lastly the volcanic. The alluvium we have placed
in various situations, overlaying the older rocks.

AQUEOUS CAUSES OF CHANGE, 197

CHAPTER III.

Aqueous Causes of Change.

" The rivers swell,

Of bonds impatient. Sudden from the hills,
O'er rocks and woods, in broad, brown cataracts,
A thousand snow-fed torrents shoot at once ;
And where they rush, the wide resounding plain
Is left one slimy waste." Thomson.

in the preceding chapter we have given a general view of the
arrangement of the strata which compose the crust of the earth.
We now proceed to consider the changes at present going on in
the organic and inorganic kingdoms of nature. We will thus be
better prepared to admit that the fossil remains which occur
everywhere in the stratified rocks, and that the stratification of
those rocks, are results of laws now in full operation, but exerted
through a period of years, it would be utterly vain to attempt to
estimate. In the present chapter, which presents us with a sub-
ject which of itself might f..>rm a volume, we can only hastily
glance, at some of the most active causes of change now in ope-
ration, those who desire to learn more will find ample informa-
tion in the writings of Lyell, Mantell, Buckland, and other well
known geologists.

Although from the very nature of the case, geology is some-
what a speculative science, since it takes into consideration the
changes and vicissitudes which tha earth has undergone, during
ages so remote, that the mind can with difficulty conceive of the
lapse of time past, and endeavors to explain them by the applica-
tion of laws now in action, but whose silent operation is unheeded
by the great mass, yet it at the same time presents us with the
noblest views of the material universe; and the philosophic mind,
in reviewing ever so cursorily, the traces of the past, cannot fail
to be struck with the harmony of the material world. Everything

198 THE WORLD.

around us is in a most active state of change, literally speaking
there is no such thing as rest. Every operation of nature, how-
ever minute and familiar, the heat and the cold, the moisture and
the drouth, the warmth of summer and the frosts of winter, the
snow and the ice, nay, every drop of rain that falls from the at-
mosphere, performs its sharj in displacing and renewing the solid
crust of the earth, and contributes its alloted portion in carrying
on the great work of universal metamorphosis and change. The
great agents of change in the inorganic world may be divided
into two classes, the aqueous and the igneous. To the aqueous
belong rivers, torrents, springs, currents, and tides ; to the ig-
neous volcanoes and earthquakes. Beside these we may enu-
merate the agency of the atmosphere, which is partly mechani-
cal, and partly chemical; and vital action. We shall consider
these several agents of change in order, and see their present
effect in changing the sea to land, and land to sea; in excavating
valleys and destroying hills ; in the transition of dry ground to
marshes, and the reverse ; the occurrence of earthquakes and
their phenomena; the uniting of islands with main lands, and
insulation of peninsulas.

In this manner, although we may not be able to comprehend en-
tirely the degrading and elevating causes above enumerated, yet
we will see abundant means for the conversion of the soil upon
which we now tread, from the bed of an ocean to dry land; we
shall see how wood has been changed into stone, and plants and
fishes imbedded in solid rock. We shall first consider the action
of running water. The heated atmosphere which sweeps over
the vast ocean and the surface of the earth, absorbs and carries
with it an immense amount of aqueous vapor, to be again de-
posited when the air is cooled, in the form of clouds, mist or rain,
A large amount of this moisture is deposited upon mountains and
elevated lands, and thus the more elevated regions become per-
petual reservoirs of water, which flows down in gentle streams
and rivers, irrigating the plains below. At the first glance we
might suppose the amount of water carried up into the air by
evaporation was of too trifling a nature to be instrumental in ef-
fecting any great mechanical change, but a moments reflection

ACTION OF RUNNING WATER. 199

will convince us that the amount is almost beyond estimate. All
the rivers on the face of the earth are constantly pouring their
waters into the sea, and yet its level is not affected in the slight-
est degree, hence we infer that the quantity of mositure evapo-
rated from the surface is exactly equal to the sum of all the rivers
of the world. If the evaporation and restoration of the waters
were all the effect which- is produced by the agencies just de-
scribed, little change would be accomplished upon the face of the
country over which the waters might flow in their passage to the
sea. But in the more elevated tracts of country, -the atmosphere
acts powerfully upon the soil, a':d by the influence of heat and
cold, by dampness and dryness, and of frost and rain, loosens the
most coherent masses and disintegrates the solid rocks. The
mountain streams flow down more or less charged with earthy
matter, worn from the soil and rocks over which they flow, Jn
their passages toward the sea, sometimes over an immense tract
of country, they often unite and pour their waters along with al-
most irresistible fury. The solvent power of the water assists
very materially in degrading the rocky channels through which
it flows, and acts powerfully on the alkaline and calcareous ele-
ments of the soil, and especially when it holds carbonic acid in
solution, which is almost always the case. When the earthy mat-
ter and pebbles are thus intermingled with running water, a new
mechanical power is gained, by the attrition as they are borne
along, thus sapping and gradually undermining high banks and
rocks, until at length the overhanging mass is precipitated into
the current and swept away by its waters. In this manner, islands
are cut off from the main lands, and shoals, and rich earthy de-
posits called deltas ure formed at the mouths of rivers. There is
nothing so very remarkable in the power of currents to transport
even heavy masses of stone, for we must remember that the spe-
cific gravity of water is much greater them air, and a stone im-
mersed in a stream will loose about half its weight, and many of
the lighter particles of the soil will almost float.

Sir George Staunton estimated that the quantity of sediment
borne down by the Yellow River in China, in a single day, was
equal to forty-eight millions of cubic feet, and late observations

200 THE WORLD.

upon the Ganges, at the time of its flood, or in the rainy season,
when it is fully charged with sediment, shows that it discharges
6,082,041,600 cubic feet in 122 days, and during the three months
of hot weather, and the five months winter, it discharges 286,-
035,840 cubic feet more, a quantity small compared with the for-
mer, the total annual discharge is therefore 6,368,077,440 cubic
feet.

"In order" says Mr. Lyell, "to give some idea of the magni-
tude of this result, we will assume that the specific gravity of the
dried mud, is only one-half that of granite (it would . however,
be more), in that case the earthy matter discharged in a year,
would equal 3,184,038,720 cubic feet of granite. Now, about
12£ cubic feet of granite weigh one ton, and it is computed that
the great Pyramid of Egypt, if it were a solid mas^ of granite,
would weigh about 6,000,000 tons. The mass of matter there-
fore carried down annually, would, according to this estimate,
more than equal in weight and bulk forty-two of the great pyra-
mids of Egypt, and that borne down in four months of the rains,
would equal forty pyramids. The base of the great Pyramid of
Egypt covers eloven acres, and its perpendicular height is about
five hundred feet. It is scarcely possible to present any picture
to the mind which will convey an adequate conception of the
mighty scale of this operation, so tranquilly and almost insensi-
bly carried on by the Ganges. It may however, be stated, that if
a fleet of more than eighty Indiamen, each freighted with about
1400 tons weight of mud, were to sail down the river every hour
of every day and night for four months continually, they would
only transport from the higher country to the sea, a mass of solid
matter equal to that borne down by the Ganges in the flood sea-
son."

The same effect is observable in the mighty rivers of America.
The Mississippi annually bears down upon its swollen stream in-
numerable quantities of trees and sediment, which are imbedded
in the basin of the sea at the mouth of the river. In this manner
the remains of animals and vegetables are being continually en-
veloped, and, should these deltas some day become dryland, the
naturalist could determine by a study of the imbedded remains,

fcXCAVATION' O*1 A LAVA CURRENT.

201

the character of the country through which the stream had flowed.
Below we give a diagram showing the excavation of a lava cur-
rent by the action of the river Simentb, one of the largest of the

Sicilian rivers, which flows at the base of Etna. A A, bed of lava
which has flown to a distance of five or six miles; B, bed of the
Simento; C, foot of the cone of Etna; D, marine and volcanic
strata; E, ancient bed of the river. The lava current in which
the channel is eroded is one of the more recent, having been
ejected in 1603. In a little more than two centuries the Simento
has worn a passage from fifty, to several hundred feet wide, and
in some parts from forty to fifty feet deep. The portion of lava
cut through, is not porous, or mixed with cinders and scoria, but
consists of a compact homogeneous mass of hard blue rock. The
Falls of Niagara afford a magnificent example of the progressive
excavation of a deep valley in solid rock. It appears from exami-
nation that the Falls were once at Queenstown, about seve^i miles
below their present position. It is possible however that a natural
chasm may have previously been formed a part of this distance,
which the river has since widened, although a careful study of
the face of the country, and also the existing proofs, at various
places, several miles below the present falls, of fluvatile deposfts,
seem to show conclusively that the falls have gradually receded
from near the present site of Lewiston and Queenstown.

When by the meTting of snows and ice, an unusual amount of
water is accumulated at some high point, and the barriers which
have been restraining it give way suddenly, the flood sweeps on-
ward with a fury which overcomes every obstacle. Such was the
flood in the valley of Bagnes, described by Mr. Lyell, in his Prin-
ciples of Geology. The bed of the river Dranee being blocked

20*J 1HE WORLD,

up by the avalanches of snow and ice, a reservoir or lake, was
thus formed, about half a league in length, two hundred feet deep*
and seven hundred feet wid». To lessen the mischief appre-
hended from the sudden bursting of this ice barrier, a channel
Was cut through the ice about 700 feet in length ; the flow of the
waters deepened this channel until nearly half the contents of
the lake were drained off* but on the approach of the hot season,
the remaining mass gave way with a trfmendous crash, and the
residue of the lake was emptied in half an hour. As the mass
of waters and floating ice swept through the narrow gorges, it
rose sometimes to an immense height, to burst again with in-
creased fury into the next basin, sweeping along rocks, forests,
bridges, and cultivated lands. Immense fragments of granite
rock were torn from the ancient soil and borne down ; one of
these, was sixty paces in circumference.

The Deltas, or triangular sedimentary deposits which are formed
at the mouths of large rivers, often exhibit distinct marks of strati-
fication, and when they terminate in an extensive estuary, or arm
of the sea, the layer of mud brought down by the river is regu-
larly covered by a layer of sand, borne in and deposited upon the
mud at each returning tide. It is in this manner that the ripple
marks, and tracks of vermes, and molusces, are preserved. Every
one must have noticed, in walking along a sandy shore, at low
water, the undulating surface of the mud or sand, caused by the
little ripples in the water, and also the varied tracks of worms,
shell-fish, and birds. When a thin" layer of mud happens to be
deposited over these before the next return of the waves, a perfect
cast is thus obtained. Mr. Lyell, in his travels in North -America
mentions that he had obtained at Wolfville, on the Bay of Fundy,
thin slabs of the dried red mud, which presented perfect impres-
sions, on the upper side, showing the recent foot-prints of a small
sandpiper, as it marched over the soft -mud,"'which had after-
wards so much hardened in the sun as to become consolidated,
and upon the under surface exhibiting a. cast of the impressions
made in a previous deposit. The red sediment, or mud deposited
by the waters of the Bay, is obtained from undermining cliffs of
red sandstone, and soft red marl, and whenever the velocity of the

ILUVIATILE fORBitlONS. 203

current is suspended by tlie rush of the tides, this mud is thrown
down, and very large, and widely extended tracts, of rich soil,
have thus been formed, and thousands of acres have been ex-
cluded from the encroachments of the sea by artificial embank-*
ments. At the time of very low tides, this soft mud is sometimes
exposed to the sun for several days, and thus becomes sufficiently
baked or consolidated, to a depth of several inches, to resist the
flow of water, which soon deposits upon it another thickness of
mud. We shall see that in a precisely similar manner, footprints,
of high antiquity, were formed in the strata of new red sand-
stone of the valley of the Connecticut, and also in Europe.

The large rivers which flow from south to north in the northern
latitudes, having their sources in a much wanner latitude than
their mouths, become swollen in their progress northward, on
account of the ice which has not yet been broken up, hence they
overflow and sweep through the forests of pines and birches, and
carry away thousands of the uprooted trees- The timber thus
drifted down is often laden with the earthy deposit around the
roots, and beinjj deeply sunk in the water, other masses become
piled upon it until at length becoming water-logged it sinks and
is imbedded in the strata if there be any forming. "As the trees"
says Dr. Richardson, "retain their roots, which are often loaded
with earth and stones, they readily sink, especially when water
soaked ; and, accumulating in the eddies, form shoals which ul-
timately augment into islands. A thicket of small willows covers
the new formed island as soon as it appears above the water, and
their fibrous roots serve to bind the whole firmly together. Sec-
tions of these islands are annually made by the river, assisted by
frost, and it is interesting to study the diversity of appearances
they present, according to their different ages. The trunks of the
trees gradually decay until they are converted into a blackish
brown substance, resembling peat, but which still retains more or
less of the fibrous structure of the wood ; and layers of this often
alternate with layers of clay and sand, the whole being penetrated
to the depth of four or five yards or more, by the long fibrous roots
of the willows." A deposition of this kind, with the aid of a
little infiltration of bituminous matter, would produce an excellent

204 THE WORLD.

imitation of coal, with vegetable impressions of the willow roots.
We will clpse this chapter with a discription of those extensive
accumulations of vegetable matter called peat bogs. These are
marshy grounds covered with successive layers or beds of mosses,
re-eds, equisetae, rushes, and other plants which affect a marshy
soil; but a species of moss called sphagnum palustre, which has
thB peculiar property of throwing up new shoots in its upper part
whilst the lower is decaying, forms a great part of the peat bogs
of Europe. It is said that one -tenth of Ireland is covered by
these marshy bogs, in which trees are often found standing erect,
with their roots imbedded in the sub-soil ; thus presenting evi-
dence of the formation of the bog since the growth of the trees;
these are generally oaks where the sub-soil is clay, and firs where
it is sand. The peat bogs of the north of Europe occupy the
areas of the ancient forests of oak and pine. At the bottom of
peat bogs, cakes of oxide of iron, termed bog-iron ore are found,
partly precipitated from mineral waters, and partly from the de-
caying vegetable masses.

One of the most remarkable facts connected with the peat bogs,
is the preservation of the bodies of men and animals for an in-
definite period of time; in many instances they are converted
into a peculiar fatty substance, which resembles spermaceti,
called adipocire. In June 1747, the body of a woman was found
six feet deep in a peat-moor, in Lincolnshire. The antique san-
dals on her feet afforded evidence of her having been biiried there
for many ages ; yet her nails, hair, and skin, are described as
showing hardly any marks of decay. On the estates of th» Earl
of Mori a in Ireland, a human body was dug up a foot deep in
gravel, coVered with eleven feet of moss ; the body was com-
pletely clothed, and the garments seemed all to be made of hair.
On the confines of England and Scotland, is a flat area, about
seven miles in circumference, known as the Solway moss. It is
a boggy ground covered with grass and rushes, presenting a dry
crust and fair appearance, but it shakes under the least pressure,
the bottom being unsound and semi-fluid. The adventurous
passenger, who sometimes in dry seasons, traverses this perilous
waste, to save a few miles, picks his cautious way over the rushy

BOGS. 205

l&ssocks as they appear before him, for here the soil is firmest.
If his foot slip, or if he venture to desert this mark of security, it
is possible he may never be heard of. In 1772 on the 16th of
December, this moss being filled with water during heavy rains,
burst, and a stream of black half-consolidated mud began to creep
over the plain, it overwhelmed some cottages, and covered an
area of 400 acfes to a depth of fifteen feet. Dr.^Jackson men-
tions that in the peat bogs of Maine, a substance exactly similar
to cannel, or anthracite coal, is found amidst the remains of
rotten logs of wood, and beaver sticks. It is a true bituminous
coaU probably formed from the balsam-fir during its long immer-
sion in the humid peat,

We have now briefly considered the action of rivers, and run-
ning waters, their effect in carrying down to the ocean or lake
avast quantity of sediment, which is finally deposited, and sub-
quently, either by pressure, or exposure to air consolidated into
rock ; that large tracts of country callea deltas, at the mouths of
rivers, are in progress of formation, in which are buried the re-
mains of animals and vegetables, and in which, are preserved
the tracks of ,worms, molusces, and birds ; that by collections of
rafts upon the large rivers, laden with stones, earths, and sands,
islands are forming, and the materials for future beds of coal
collecting ; that peat bogs are how growing, and, bursting their
barriers, flooding whole tracts of country, and imbedding forests,
and the habitations of men. By similar actions, exerted at the
most remote periods, the*present strata of the earth's crust
were deposited, and the masses of limestones, sandstones, and
shales, were formed^ We are thus irresistably led to the conclu-
sion, that however remote may have been the date of these for-
mations, or however deep they may now be buried below the
present surface, they were once exposed, and over their surface
living things moved, and upon it lay the wrecks of organic
matter.

The entire absence of human remains or works of art in the
anciently formed deposits, and their extreme abundance in mod-
ern alluvium, is a sufficient proof of the comparatively recent
origin of the human race. It cannot be doubted that human re-

206 THE WORLI/.

mains are as capable of resisting decay as the harder parts o:l*
many inferior animals. Such remains however, except in places
subject to great change from volcanic action, or the shifting and
filling up of the ancient channels of rivers, are never discovered.
The inference is plain, and we are irresistibly led to the conclu-
sion, that long antecedent to the date of man, the surface of the
earth teemed with life ; and that it has been subject to mighty
revolutions, which have, at once swept off its face, whole races of
its former inhabitants, whose fossilized remains have formed the
bed of a mighty ocean. It was therefore a splendid boast, that
the deeds of the English chivalry at Agincourt made Henry's
chronicle

as rich with praise

As is the ooze and bottom of the deep
With sunken wreck and sunless treasuries 1

AQUEOUS CAUSES OF CHANGE. 207

CH.A PTE R, IV.
Springs*

" Thou dost wear

No stain of thy dark birthplace ; gushing up
From the red mould and slimy roots of earth,
Thou flashest through the sun."

Bryant*

IN the present chapter we shall consider another aqueous cause
of change, springs, or as they have been termed " subterranean
drainage." Every one is familiar with the fact, that the water
which is deposited upon the loose soil, easily percolates through
it, and makes its way downward to a certain depth according to
the nature of the underlying strata. Whilst it easily penetrates
through the gravelly, and sandy formations, it is arrested by the
almost impervious beds of clay, and sometimes collected into
large sheets of water, which are often subjected to intense press-
ure, upon the well known hydraulic principle so often employed
in the arts under the form of the hydrostatic press. Mr. Lyell
mentions that the transmission of water is so rapid through the
loose gravelly soil over which the river Thames flows, and which
is upon an impervious sub-stratum of clay, that the wells in this
vicinity alternately ebb and flow, with the tides of the river. It
is from this cause, that wherever on the side of a hill, strata of
clay are found below sandy soils, the water oozes out, not indeed
in a continuous sheet, but, probably from »«me slight difference
in the constitution of the clay, or from natural fissures or cracks,
in the form of little streams. The effect of such minute streams
in finally undermining hilly tracts of country is surprising ; con-
stantly running, they bear out the light sand, and thus the sub-
terraneous reservoir extends its surface gradually, until, at length,
the superincumbent mass gives way, and sliding upon the slip-
pery cl£y is precipitated yito the valley below.

206

THE WORLD-

Much light has been thrown upon the theory of springs by the
boring of what are called "Artesian Wells," so called from hav*
ing been first made at Artois in France ; they are made by boring
the earth with a large augur, three or four inches in diameter, if
a hard rock is met with, it is triturated with an iron rod, and the
fragments are then easily removed ; as the boring proceeds, tubes
are introduced to prevent the sides from caving, and also the
spreading of the water through the soil. In this manner a well
was bored for Holt's Hotel, in the city of New York ; 126 feet of
stratified sands, clay, and river mud, were first penetrated before
reaching the gneiss rock which underlies the island, 500 feet of
'this rock was subsequently bored through, and an abundant sup-
ply of good water obtained. When a vein of water is struck,
it often rushes up with great force, rising several feet above the
surface, affording a constant supply of water. Borings have been
made in France to a depth of 1200 and even 1500 feel. Occa-
sional failure is experienced in boring, sometimes on account of
the geological structure of the country, and often from the exis-
tence of subterranean outlets for the water. The following dia-
gram is from Mr. Lyell, and will illustrate the principle of the

Artesian wells. Suppose a a, to be a porous stratum lying upon
an impervious bed of clays and marls, d; and covered by another
mass of impenetrable rock e. Suppose now that at some point
as at b, an opening be made which gives a free passage upward
to the water confined at a a, at so low a level as to be subjected
to the pressure of a considerable column of water, which we may
suppose collected at /, in a more elevated district. The water
will rush out at 4, and rise to a considerable height; and if there
should happen to be a natural fissure at c, a spring would be pro-
duced. Among the curious facts made known by the borer, is
the existence of distinct sheets of water, in Btrata of differen

SPRINGS. 209

ages and composition, and also of subterranean passages. At
Tours, seeds and stems of marsh plants were brought up, and in
such condition that they could not have been more than three or
four months in water; and at Westphalia, small fish were thrown
out, three or four inches long, the nearest streams being at the
distance of some leagues. laboring an Artesian well near Buf-
falo, recently, for the purpose of obtaining pure water for the use
of the Gas Works, after having penetrated some 25 feet from
the surface, the laborers came upon limestone rock ; upon pene-
trating thjs rock twenty-five inches, the drill fell into a cavity, and
upon being withdrawn a jet of water followed, and continued to
,flow, until the water in the well rose to the level of the lake. Sub-
sequent observations have shown Lake Erie to be the supply
fountain, for when the waters of the lake rise or fall, by the action
of wind, the water in the well changes its level in conformity-
It appears thdt one of the large and numerous fissures common
in this particular series of rocks, and which in this case commu-
nicated with the lake was pierced by the drill, and furnishes a
fine illustration of the law which governs the production of
springs and fountains.

By the long continued action of underground streams, caverns
and fissures, are formed and enlarged, and it is highly probable
that rivers are flowing within the surface of the earth. In Staf-
fordshire there is a spring which discharges annually more water
than all that falls in the surrounding country. In Virginia, ten
miles from Harrisburg, is a spring called the " Big Spring." It
rises suddenly from the foot of a limestone hill, and continues a
stream some yards in breadth, and half a foot deep, with force
sufficient to turn two largo mills. At Kingston, Rhode Island,
there is a spring which rises from primitive rocks, and dischar-
ges such a quantity of water that JL grist-mill has been driven by
it for a great number or years, and more recently a large cotton
factory has been erected, which depends entirely upon the water
of this spring to turn the whole machinery. In flowing through
the different strata, springs become impregnated with various min-
eral substances. The solvent power of water exceeds that of
any other liquid, and hence most spring waters are charged with

210

THE WORLD.

mineral substances; or with some gas. The presence of carbon-
ate of lime, or lirne in combination with carbonic acid, is easily
shown by the calcareous lining or incrustation of a tea-kettle, or
a boiler which has been sometime in use. Some springs contain
so large a quantity of calcareous matter that they throw it down
as they flow along, incrusting various objects which are placed in
them. The springs of Derbyshire England, are particularly re-
markable for this, and incrustations of leaves, branches, bas-
kets &c., are easily procured. At the baths of San Fillippo, in
Tuscany, where the waters are highly charged with carbonate and
sulphate of lime ; medallions are formed by first directing the
water to a cistern where the sulphate of lime, (gypsum) is do- ,
posited. It is then conveyed to a chamber through a tube, from
the end of which it falls ten or twelve feet, the current being bro-
ken by numerous small sticks crossing each other, by which
means the spray is dispersed about the room. The Vnoulds of the
medallions are placed underneath, rubbed over with a little soap,
and the water striking upon them leaves particles of carbonate
of lime, which, gradually increasing, finally gives an exact and
beautiful white crust. So rapid is the deposition of earthy mat-
ter by these springs, that a stratum of stone a foot thick is annu-
ally deposited, and is employed for building purposes. The hill
of San Vignorn, in Tusca~ny, a few miles from San Fillippo, has
a thermal spring upon its summit, and from this opening, a deposit
of travertine, or concretionary limestone has been formed two
hundred feet thick, and of great hardness. We must be careful
and not confound these incrustations with true petrefactions. In
the one case, as for example an incrusted twig, the inclosed sub-

stance will be found to have undergone no alteration, but that of
natural decay, but a'true petrefaction, is saturated throughout with

CALCAREOUS SPRINGS. 211

mineral matter, every part of its structure having undergone some
change, so that if we break and polish such a specimen, every
part of its structure, converted perhaps into flint, may be detected;
even the minute ramifications and delicate tissues of many kinds
of wood, and most delicate parts of the internal structure of bones.
By the infiltration of water through limestone rocks, the sparry
concretions are made which depend in caves, like icicles,
they ar» called stalactites, from a Greek word meaning to drop,
and also under them, from the drippings, are stalagmites, or drops,
and when, as frequently happens, the two unite, a singularly pic-
turesque effect is produced, the caves appearing as if supported
by pillars of extraordinary beauty and variety. Sometimes a
jinear fissure in the roof, causes the formation of a translucent
curtain or partition. This is the case in 'Weyer's cave, in the
limestone range of the Blue Mountains, a narrow and rugged
fissure leads 'to a large cavern where the most grotesque figures
present themselves, formed by the infiltration of water through
the limestone. Passing from these the passage conducts to a
flight of steps that leads into a large cavern of irregular form and
great beauty, about thirty by forty feet in dimensions. Here the
incrustations hang like a sheet of water that has been frozen as it
fell. Farther on is another vaulted chamber, one hundred feet
long, thirty -six wide, and twenty-six high ; still farther is anolh-
range of apartments, at the extremity of which, is a hall two hun-
dred and fifty feet long, having a splendid sheet of rock work
running up the centre. The whole length of this extraordinary
group of caverns is not less than one thousand six hundred
feet.

The most celebrated grotto in Europe, is in the island of Anti-
paros, it consists of a series of caves, the roof, the floor, and the
sides of which, are entirely covered with a dazzling incrustation.
Immense columns of alabaster extend from the roof to the floor,
and others hang in fine cubic forms above the head; the crystali-
zation of alabaster has nowhere else been observed.

Although the phenomena produced by incrusting springs, are
perhaps not of much importance in modifying or changing the
surface of the earth, yet the changes effected by this process, in

212 THE WORLD.

strata composed of loose materials are of very great importance;:
for by an infiltration of carbonate of lime, sand is converted into
sandstone, and soft cbalk into solid rock, and the loose shells of
Florida into compact stone. By this agency, the beds of recent
limestone in which human skeletons are sometimes found, have
been formed, and are now in progress of formation, along the
shores of the whole West Indian Archipelago^ On the north-

east corner of the main land of Guadalope, is a bed c/f recent
limestone, nearly submerged at high tides. In it are found shells,
fragments of pottery, sto-ne arrow-heads, wooden and stone or-
naments, and human skeletons. It is quite evident that the rock
must have been soft and yielding when these remains were first
deposited, they are not fossilized, for the bones still retain their
gluten and phosphate of Erne. In the wood cut, we give a repre-
sentation of one of these human skeletons which is now in the
British Museum, it is that of a female ; the head of this skeleton.
has been carefully examined by Dr. Moultrie, and is now in the
museum of the Medical College at Charleston, South Carolina-

CALCAREOUS SPRINGS. 213

This skeleton appears, from the craniological developments, tq
have belonged to a Peruvian, or to some orie of a similar race,
being entirely dissimilar to the skulls of the Caribs, or ancient
possessors of the island. Another skeleton in a sitting posture is
in the museum at Paris. The formation of this limestone is as
follows. The sea which surrounds the Bermudas, abounds in
corals, and shells, and from the incessant action of the waves,
the water becomes charged with calcareous matter, and a portion
of this is borne by the waves to the shore, and deposited in the
form of calcareous sand, which becomes compact limestone, on
the infiltration of crystalized carbonate of lime. A great part of
the detritus is thrown down in the depth of the ocean, and there
envelopes the remains of vegetables and animals, forming new
strata for the investigation of future ages.

Carbonate of lime is not the only mineral substance held in so-
lution by water, but silicious earth, or the basis of flint, which
constitutes so large a proportion of the surface of the earth, is found
in great abundance in some springs. It is true, that even in
the present advanced state of chemical knowledge, we are unac-
quainted with any process by which any large proportion of flint
can be held in solution bv water. Yet we have unquestionable
proofs that in the great laboratory of nature, this is effected on a
large scale, as for example in the Geysers of Iceland, and the
springs of Carlsbad in Bohemia, and the thermal springs of
St. Michael, in the Azores. It seems necessary in order that
water should contain any large quantity of silica in solution, that
it should be raised to a high temperature, and silicious springs are
mostly thermal, and are generally found in volcanic regions.
The most celebrated thermal springs are those of Iceland, termed
the Geysers. The waters of these boiling springs contain a large
amount of silex which is deposited on cooling, upon various sub-
stances, similar to the incrustations of carbonate of lime already
noticed. The hot springs of Iceland are situated in the south-
west section of the island, and more than a hundred of them are
found in a circuit of two miles. They rise through a thick cur-
rent of lava, which may have flowed from Mt. Hecla, whose sum-
mit may be seen at a distance of about thirty miles. It is said
j*

214

THE WORLD.

that the rushing of the waters may be heard as they flow in their
subterranean channels. ' The springs are intermittent, a fountain
of boiling water accompanied with a great evolution of vapor,
first appears, and is ejected to a considerable height, sometimes
as much as one hundred feet, a volume of steam succeeds, and
is thrown up with great force and a loud noise, similar to the es-
cape of steam from the boiler of an engine. This operation con-
tinues sometimes for more than an hour, though generally not
longer than ten minutes, and is succeeded by a period of rest of
uncertain duration, and then a repetition of the same phenomena.
We give a view of the crater of the great Geyser reduced by Mr.
Lyell, from a sketch by J. W. Hooker, M. D. The basin of the
great Geyser is an irregular oval about fifty-six feet, by forty-six,
the silicious mound of which it is formed, is about seven feet
high. In the centre is a pipe s'eventy-eight feet in perpendicular
depth, and about sixteen feet diameter at the top, but contracting
to ten feet lower down. The circular basin is represented as

empty, but it is usually filled with a beautifully transparent water
in a state of ebullition ; the inside of the basin is smooth and
formed of a whitish silicions deposit, as are also two channels at

SILIC10US SPRINGS. 215

«ach side, by which the water escapes wheji the basin is full. It
is said that an eruption may be brought on in a few minutes by
throwing stones down the pipe, these are again ejected, oftentimes
wjth immense violence. The theory of the action of these hot
springs of Iceland has not yet been satisfactorily given ; the heat
however, is supposed to be derived from subterranean volcanic
fires. The silicious water from these springs incrusts plants,
twigs, and leaves, similar to the calcareous springs. In the island
of St. Michael there are hot springs very strongly impregnated
with silica; wherever the water has flowed, sinter or precipitated
rock, is formed intermixed with the clay, including grass, ferns,
and reeds, in different stages of petrefaction ; branches of the
same ferns which now flourish in the island are found completely
petrified, preserving the same appearance as when vegetating.
There are many springs in this country which deposit silicious
and calcareous matter.

Iron is found in the waters of almost all springs, and some of
them are so copiously impregnated with this metal that they stain
the rocks or herbage over which they flow. The iron which is
thus borne out of the earth and deposited into the sea, acts as a
cement to bind together the subaqueous deposits now forming.

Many of the ancient sandstones are cemented and colored by
iron, and pebbles are firmly bound together in ferruginous con-

«I6 THE WORLD.

glomerate. Occasionally nails, or other pieces of iron, are found
in the centre of a hard nodule of sandstone, formed by this pro-
cess. The engraving, from Dr. Mantell's " Wonders of Geolo-
gy," is a very" interesting- specimen, it is a conglomerate of glass
beads, knives, and sand, cemented together by an infiltration of
iron, derived from the oxidation of the blades. It contains two
silver pennies of Edward I, and was dug up at a depth of ten
feet in the river Dove in Derbyshire. The coins are presumed
to have been a part of the treasures contained in the military chest
of the Earl of Lancaster, which was lost in crossing the river in
the dark ; more than five centuries must therefore have elapsed
since its submersion. The ore called bog-iron, is formed by the
infiltration of water impregnated with iron, and various kinds of
wood are colored black by the same cause. Iron, it is well known
is one of the chief ingredients in many celebrated mineral wa-
ters, frequently in the shape of a carbonate. The consolidation
of sand and other loose materials by the agency of mineral wa-
ters, is everywhere going on, and in much greater extent than
can be easily comprehended ; small and apparently simple as are
the means employed, yet the effects are magnificent.

The detritus borne down by the mountain streams falls at last,
quietly into the ocean, or is deposited upon the rich soil of some
delta, after a certain time the mass is cemented together by other
mineral ingredients dissolved in the water, and beds of compact
stone, in which are entombed the remains of animate and inani-
mate existence, are formed slowly but surely, for ihe use of most
distant generations. The twigs and leaves, and insects, which
fall into the petrifying springs are incrusted with a coating of
stone, or are slowly transmuted into mineral substance for the
inspection and admiration of a future race. Thus the change
continually goes on. The frost, the storm, and the stream, and
in many volcanic districts the carbonic acid, continually given off,
as for example, in the neighborhood of the extinct volcanoes of
Auvergne in France, cause even the granite rocks to crumble
and fall away; but in a thousand other places the process of re-
union is going on, and different kinds of stone are being formed
from the ruins of the old. Besides the springs to which we have

SALT SPRINGS. 217

referred, there are others very numerous impregnated with petro-
leum, and the minerals allied to it, as bitumen, naptha, asphaltum
und pitch. These springs are found in all parts of the globe, but
tjfce most powerful yet known, are those on the river Irawadi, in
the Birman Empire, there being five hundred and twenty wells
in one locality, yielding annually 400,000 hogsheads of petroleum.
On both sides of the island of Trinidad, fluid bitumen is seen to
ooze up from the sea. In the island is a pitch lake about three
miles in circumference. The asphaltum is sufficiently hard to
support heavy weights in cold and wet weather, but during warm
weather it is nearly fluid. In some places it is covered by the
soil, and large crops of tropical productions are raised upon it, so
that it is difficult to ascertain the boundaries of the lake. Mr.
Lyell supposes that the materials for the formation of this bitu-
men, have been-borne down by the Oronoco into the sea; and, col-
lected by eddies or other causes into particular regions, have been
acted upon by submarine volcanic fires. The frequent occur-
rence of earthquakes, and other volcanic phenomena in the island,
lends countenance to this opinion.

In addition to those above mentioned, we may enumerate
the saliferous or brine springs, which are everywhere so common
over the globe. The agency of these springs, in the formation
of rocks, is of less importance than that of the calcareous, or the
silicious. Often they are strong solutions of pure rock salt, or
muriate of soda, and furnish large quantities of that valuable ar-
ticle for the purposes of domestic economy. Such are the salt
springs in the neighborhood of Salina, and Syracuse, in the State
of New York. At Salina, the well is seventy feet deep, and
about 480 gallons of brine are raised in one minute, and Dr.
Beck states that 43^ gallons are required to yield a bushel of salt,
weighing 56 Ibs. The well at Syracuse 170 feet deep, the pumps
raise 62 gallons per minute, and 46 gallons are required to make
a bushel of salt. The water is clear and sparkling, and of a tem-
perature of 50° (Fahr.) at Salina, and 51° at Syracuse. These
salt springs are supposed to be owing to immense beds of rock
salt, although no borings yet made, have reached these beds. The
valleys of the Mississippi and the Ohio abound in salt springs.

218 THE WORLD.

and are based almost wholly on the saliferous or salt bearing rocks.
Two distinct strata of these salt rocks, known as the upper and
lower salt rocks, are found on the Muskingum, about 400 feet
apart. The stone itself is a white, or sometimes reddish tinted aqjl
porous sandstone, the upper, is 25 feet thick; and the lower 40, and
this yields the strongest brine. At Cheshire England, are nu-
merous brine springs, and the salt springs of Droitwitch, a small
town in Worcestershire, are superior to any other in the island;
they are supplied from beds of rock salt, or rather veins, lying be-
low a bed of gypsum ; for a long time the salt was made only
from the brine which penetrated this bed, but about a century ago
it was bored through and a large salt river was found to flow be-
low. The depth of the river of brine below the surface, is about
200 feet, 150 6f which are gypsum ; the river flows over a bed of
rock salt and is twenty-two inches deep. The origin of these
extended deposits of salt has not yet been satisfactorily ascertained.
The waters of the Dead Sea in Palestine, contain large quantities
of muriatic salts, derived from entire rocks of this mineral, con-
tinually dissolving on its southern shore. The water contains
forty-one parts in one-hundred of salt ; a much greater propor-
tion than that of the sea. It is impregnated also with other min-
eral substances, particularly bitumen, which floats upon its sur-
face in such large quantities as would elsewhere sink. The vol-
canic appearance of the country, the almost perpendicular, black
rock which bounds its eastern or Arabian side, and throws its
black shadow over the dark waters, and the limestone and sandy
cliffs on its western side, which tower up in fanciful shapes, lends
countenance to the opinion that these mineral substances are the
products of former volcanic action. We have now glanced at the
most prominent effects of springs in modifying and changing
the face of the globe ; although the effect of any individual spring
appears trifling, yet the aggregate of change either by disintegra-
ting, or consolidating, is immense. We have already alluded to
the transporting power of rivers. The small stream which is
supplied by springs, and which flows for hundreds of miles with
a power which seems scarcely sufficient to cany along a few
sands, by continual accessions swell* finally into an immense

SUBTERRANEAN SPRINGS. 219

river, and when, from long continued rains, or frem melting of
snows and ice, the brooks and tributary streams are swollen, a
flood of water is poured down to the ocean, which bears with it
ijaaterials transported a thousand miles, and in quantities of which
we can form little conception. The water, which falls upon the
surface of the earth and penetrates its upper soil, and is thus pro-
tected from evaporation, descends lower and lower, until it meets
some impervious bed of clay, or marl ; here it accumulates and
forms a hidden pond, and slowly undermines whole tracts "of
country, and in the course of ages subterranean rivers are formed.
The various mineral ingredients dissolved in water, are borne
up by springs, and again flowing over or through the porous sands,
form limestones, sandstones, and ironstones; and thus continu-
allv the process is going on.

The action of all springs, and running waters, is to level the
surface of the earth. The streams, which always flow from an
elevated source, bear down the disintegrated portions of moun-
tains and hills, and tend continually to fill up the bed of the sea.
Unless a counterbalancing cause existed, and the elevation was
made to compensate this continual degradation or levelling, the
whole dry. land would ultimately disappear. We find in earth-
quakes and other volcanic effects the elevating power ; and al-
though, as we shall presently show, the sea may gradually en-
croach upon the shores of one country, yet the lands of another
will be gradually upheaved, and something like a balance will be
maintained. Minute therefore as are the transmutations which
are going on continually around us, and by which, long since, in
the same quiet manner, the leaf that floated down the stream, a
thousand years ago, and the insect that dropped into water, have
been incrusted, and preserved with a fidelity which mocks the
sculptor's art, yet we see that processes like these, have

" Turned the ocean -bed to rock,
And changed its myriad living swarms
To the marble's veined forms."

" How marvellous" observes Sir Humphry Davy, " are those
laws by which even the humblest types of organic existence are

220 THE WORLD.

preserved, though born amidst the sources of their destruction;
and by which a species of immortality is given to generations,
floating, as it were, like evanescent bubbles on a stream raised
from the deepest caverns of the earth, and instantly losing what
may be called its spirit in the atmosphere."

aaaifc

{•tfMPrattw* 4M&»*fc

•• ;•» vliynUijr

AQUEOUS CAUSES OF CHANGE. 221

CHAPTER V.

Currents.

** Thy shores are empires, changed in all save thee —
Assyria, Greece, Rome, Carthage, what are they ?
Thy waters wasted them while they were free,
And many a tyrant since ; their shores obey
The stranger, slave, or savage ; their decay
Has dried up realms to deserts : — not so thou,
Unchangeable, save to thy wild wave's play —
Time writes no wrinkle on thine azure brow —
Such as Creation's dawn beheld, thou rollestnow !'*

Byron.

WE are now to consider the remaining aqueous causes o-f
change, currents and tides. The joint action of these produce
mutations of great geological interest. The tides, or the great
tidal waves which flow over the surface of the ocean at stated in-
tervals, are mainly caused by the attraction of the moon, and
hence we may show, and by no very extended chain of causation,
that the effect of the moon in altering and keeping in a state of
perpetual mutation the face of the earth, is by no means incon-
siderable. A more remote cause, the rotation of the earth upon
its axis, produces in part at least, great currents which constantly
flow in vast circuits in the Atlantic, Pacific, and Indian oceans.
In addition to the circular currents which thus flow through th&
oceans which we have named, there are immense bodies of cold
water continually moving from the polar regions towards the
central portions of the earth, and, as these currents are exhibited
superficially, or on the surface, bearing down immense fields of
ice, and since the storms and fogs of those regions are not suffi-
cient to supply this waste of the waters, we may infer that an un-
der current of warmer water passes continually from the equa-
torial to the polar regions. The polar current of the southern re-
gions seems to be more powerful than that of the northern. lee

222

THE WORLD.

islands from 250 to 300 feet above the level qf the sea, have been
occasionally seen off" the Cape of Good Hope, and were there-
fore of immense bulk, as for every solid foot seen above, there
must have been at least eight cubic feet below water. The wood
cut below exhibits one of these ice-islands, sketched by Capt.
Horsburgh; it was seen off the Cape of Good Hope, in April
1829; it was two miles in circumference and about 150 feet high,
appearing like chalk when the sun was obscured, and having the
lustre of refined sugar when the sun was shining upon it.

Undoubtedly the principal causes of Oceanic currents are the
trade-winds, of which we have already spoken. These blowing
at first directly from the north and south, over the surface of the
water, move the floating ice, and superficial water, in the same
general direction, thus at length generating a strong polar current.
The south polar current being less intercepted by the peculiar
formation of the antarctic lands, than the northern, is perceptible
in much higher southern latitudes than the current from the
north. A manifest influence is thus exerted upon the climate, to
which wo shall again allude.

The rotation of the earth, when the waters have been set in
motion from the north to the south, causes a great change in the
general direction of these currents precisely upon the same princi-
ple which has long been recognized in the case of trade winds.
For example, the current which flows north from the Cape of Good
Hope towards the Gulf of Guinea, has a rotary velocity when it
doubles the Cape of about 800 miles per hour, but when it reaches
the equator, the surface of the earth is there whirled around at

fiUI.F STREAM. 223

the rate of 1000 miles an hour, or 200 miles faster. Now if the
water was to be suddenly transferred from the Cape to the equa-
tor, this deficiency of motion would cause, (inasmuch as the earth
rotates from w6st to east) a very strong current flowing westward
at the rate of 200 miles an hour ; or with sufficient power to sub-
merge the western continent. No disturbance however occurs,
for the water, as it advances into new zones of sea which are mov-
ino1 more rapidly, gradually acquires the different velocity by fric-
tion, so that a gentle easterly, or south-easterly current is the re-
sult. When the water flows from equatorial to polar regions, a
contrary current is produced ; thus the Gulf Stream, issues from
the Bahama Channel with a rotary velocity of 940 miles an
hour, but when it reaches latitude 40°, the water is there moving
with a rotary velocity of 766 miles*an hour, or 174 miles an hour
slower, hence a westerly or south-westerly current is the result
from the excess of rotary motion retained by the stream.

Having shown some of the causes that produce oceanic cur-
rents, we will now consider more in detail the most important.
From the best accounts which we have been able to obtain, there
seems to be a general set of the waters westward from the west-
ern coast of Peru. This current flows nearly westward, but is
not much perceived until its entrance into the Indian Ocean, when,
strengthened by the northerly currents flowing from the North
Pacific, it flows along the east coast of of Africa ; after passing
through the Mozambique Channel, between Madagascar and the
continent, it unites with another current from the Indian Ocean,
and is deflected by the Lagullas banks, which lie off the southern
point of Africa, around the Cape of Good Hope. The collective
stream is about one hundred and thirty miles in breadth and from
7° to 8° warmer than the neighboring water, and runs from the
rate of two and a half to more than four miles an hour. The
Lagnllus bank rises from an immense depth to within one hun-
dred fathoms of the surface, and has perhaps been formed by the
joint action of a south-eastern and north-eastern current, which
meet here. As the main body of the current does not flow over
this bank we may conclude its total depth to be much more than
one hundred fathoms. We give here a little chart showing the

224

THE WORLD.

general direction of the great oceanic currents. The Lagullus
current after doubling the Cape of Good Hope, passes northward

along the western shores of Africa, and is called the South At-
lantic current. It then enters the Bight, or Bay of Benin, and is
deflected westward, partly from the form of the coast and partly
by the action of the Guinea current flowing from the north into
the same great ba)7. From the centre of this bay it proceeds in
an equatorial direction westerly, at the rate of ten or eleven miles
a day, to the coast of Brazil where it is divided, a portion flowing
feebly southward ; the other branch passes off the the shores of
Guinea by the West India islands, towards the Musqueto and
Honduras coasts, through the Carribean sea, flowing northwards,
passes into the Gulf of Mexico, following the bendings of the
shore from Vera Cruz to the mouth of the Rio del Norte, thence
to the mouths of the Mississippi where it receives a new impulse;
after performing this circuit, it rushes with great impetuosity
through the Bahama Channel, its velocity being about five miles
an hour, and breadth from thirty-five to fifty miles. Its course
is now north-easterly along the eastern coast of North America,
its breadth increasing and its velocity diminishing. As the cur-

OCEANIC CURRENTS. 225

rent moves along northward, it retains a large proportion of the
warmth which it had in the Gulf, and is easily recognized from
the rest of the ocean by its higher temperature, even as far north
as the banks of Newfoundland, where the temperature is from
8° to 10° above the surrounding ocean. To the east of Boston
and in the meridian of Halifax, the stream is two hundred and
seventy-six miles broad. Here it is suddenly turned to the east,
its western margin touching the extremity of the great bank of
Newfoundland, where the current sends off a branch which pro-
ceeds to the north-easf, sometimes depositing tropical fruits and
seeds upon the coast of Norway, and the shores of Ireland and
the Hebrides. The main current continues to flow and spread
out until, in the neighborhood of the Azores, it is about five hun-
dred miles in breadth. From the Azores it flows towards the
straits of Gibraltar, the island of Madeira, and the Canary isles,
along the western shores of Africa as far south as Cape Verd,
where it is again deflected by meeting the great equatorial cur-
rent flowing from the coast of Guinea to the Brazils. In this
manner, according to Humboldt, the waters of the Atlantic are
L. carried around in a continual whirlpool, performing a circuit of
13,000 miles in about two years and ten months. The branch of
the Gulf Stream Which is given off near the banks of Newfound-
land, passes northward and eastward by the coast of Scotland and
Norway, as far as the North Cape, where, being met by a polar
current from Nova Zambia, it is deflected westward along both
sides of Spitzbergen ; still influenced by the polar current, it
passes along the shores of Greenland to Davis' Straits, where it
meets a fourth current from Baffins Bay, which deflects it south-
ward towards the banks of Newfoundland, where it again meets
the Gulf Stream. Thus two great whirlpools, connected with
each other and revolving in opposite directions, touch at the
Banks of Newfoundland, which seems to be a bar cast up by
their conflicting waters. Branches of the Gulf Stream sent off
at the Azores, set from the Bay of Biscay through the English
Channel, and through St. George's Channel. The general di-
rection of these great currents may be observed on the little chart
preceding. Besides these great currents, there are local or tern-

226

THE WORLl>.

porary currents, produced by winds, the discharge of rivers, the
melting of ice, &c.

The great oceanic currents however depend upon no tempor-
ary or accidental circumstances, but like the tides, on the laws
which regulate the motions of the heavenly bodies. The lines
of coast which are subjected to their continual action, are under-
going perpetual change, the amount of this change being depen-
dant upon the exposure, and the actual constitution of the coast.
We find everywhere, the most lofty cliffs, promontories, and pre-
cipices, whatever be their composition, whether like the primary
deposits of the Shetland isles, or like the chalk cliffs of Dover, or
the diluvium of Boston Harbor, all in a state of rapid and fear-
ful destruction, crumbling away more or less quickly according to
the hardness and crystalline character of the materials which
compose them. The whole of Boston Harbor, which is now dot-
ted with small islands, was once one piece of solid land. The
diluvium which formerly covered the rocks, has been gradually
worn away by the ocean, the outermost islands present nothing
but the bare rock, and the inner ones are now being denuded.
Indeed, as Prof. Hitchcock observes, when writing of the effect
of the ocean upon coasts- exposed to its fury, " It is difficult to
examine the "coast of Nova Scotia and New England, to witness
the great amount of naked battered rocks, and to see harbors and
indentations, chiefly where the rocks are rather soft, while the
capes and islands are chiefly of the hardest varieties, without
being convinced that most of the harbors and bays, have been
produced by this agency." To witness in perfection the immense
power of the waves, urged by the tempests and currents upon
the coasts exposed to their irresistable force, we must visit the
northern isles of Scotland, and behold steep cliffs hollowed out
into deep caves and lofty arches; and immense blocks of stone
overturned and carried incredible distances. In the winter of
1802, in the isle of Stenness, says Dr. Hibbert, a tabular shaped
mass of rock, eight feet two inches, by seven feet, and five feet
one inch thick, was dislodged from its bed and removed to a dis-
tance of from eighty to ninety feet ; and on Meikle Roe, one of
the Shetland isles,- a- mass of rock twelve feet square, and five

ENCROACHMENTS OF THE SEA.

237

feet in thickness, was removed from its bed fifty years ago, to a
distance of thirty feet, and has since been twice turned over.

The long continued and violent action of the surf, finally frets
away the softer parts of islands, and nothing remains but fanci-
ful clusters of rocks, and mere shreds and patches of masses once
continents. We give below a view of the cluster of rocks to the
south of Hillswick Ness, one of the Hebrides, from a sketch by

Dr. Hibbert. These fantastic shaped rocks, which are all that re-
main of what was once an island covered with vegetation, are
striking monuments of that incessant change which, continually,
though silently and almost unnoticed, is going on, but whose
final effects are of the most magnificent character. Examples of
such rocks as are figured above, are found in many places along
the coast of the United States, where it is exposed to the action
of the storms of the Atlantic. We may be able to form some
idea of the degrading power of the ocean from the following
statement, which is given on the authority of Lieut. Mather, ge-
ologist to the first district of the state of New York.

" Vast masses of the cliffs of loam, sand, gravel, and loose
rocks, of which Long Island is composed, are undermined and
washed away by every storm. The water on the ocean coast, to
some distance from the shore, is almost always found to have

•2Xti THE WORLD,

more or less earthy matter in suspension, much of which, except
during storms, is derived from the grinding up of the pebbles,
gravel, and sand, by the action of the surf. This earthy matter
is carried off during the flood tide, and in part deposited in the
marshes and bays, and the remainder is transported seaward dur-
ing the ebb, and deposited in still water. After a close observa-
tion, I have estimated that at least 1000 tons of matter is thus
transported daily from the coast of Long Island, and probably
that quantity, on an average, is daily removed from the south
coast, between Montauk Point and Nepeaque Beach. This shore
of 15 miles in length, probably averages 60 feet in height, and is
rapidly washing away ; 1000 tons of this earth would be equal to
about one square rod of ground, with a depth of 60 feet. Allow-
ing this estimate to be within proper limits, more than two acres
would be removed annually from this portion of the coast. It is
probable that any attentive observer would not estimate the loss
of land there at I ess than this amount. Nearly one half the mat-
ter coming from the degradation of the land is supposed to be
swept coastwise in a westerly direction. There are many evi-
dences that the east end of Long Island was cnce much larger
than at present; and it is thought probable that it might have been
connected with Block Island, which lies in the direction of the
prolongation of Long Island."

A remarkable exhibition of the conjoint power of waves and
currents was exhibited during the building of the Bell Rock
Lighthouse. The Bell Rock, on which it stands, is red sand-
stone,' about twelve miles from the mainland, and from twelve to
sixteen feet under the surface at high water. At a distance of
100 yards from the rock, there is a depth in all directions, of two
or three fathoms at low water. During the erection of the light-
house in 1807, six large blocks of granite, which had been land-
ed on the reef, were carried away by the force of the sea, and
thrown over a rising ledge to the distance of twelve or fifteen
paces, and an anchor weighing 22 cwt. was thrown up upon
the rock. We are informed by Mr. Stevenson, that drift stones
of more than two tons weight, have, during storms been often
thrown upon this rock from the deep water.

ENCROACHMENTS OF THE SEA, 229

The eastern coast of England has been greatly changed by the
action of the waves, the ancient sites of towns and villages, being
now sand banks in the sea. The whole coast of Yorkshire, from
the month of the Tees to that of the Humber, is in a state of
comparatively rapid decay ; the inroads of the sea at different
points being limited by the nature of the soil, or the hardness of
the rocks. Pennant, after speaking of the silting up, or filling
up with water transported sand, clay, gravel, &c., of some an-
cient posts in the estuary of the Humber, observes, " But in re-
turn, the sea has made most ample reprisals, the site, and even
the very names of several places, once towns of note on the
H umber, are now only recorded in history; Ravensper was at
onetime a rival to Hull, and a post so very considerable in 1332,
that Edward Baliol, and the confederated English barons, sailed
from hence to invade Scotland ; and Henrjr IV. in 1399, made
choice of this port to land at, to effect the deposal of Richard II;
yet the whole of this has long since been devoured by the merci-
less ocean ; extensive sands, dry at low water, are to be seen in
its stead." Instances like these are not rare, the towns of Cro-
mer, and Dunwich, are both lost, swallowed up by the ocean,
which is now encroaching at Owthone at the rate of aboutybw
yards a year. At Sherringham, in Norfolkshire, where the pres-
ent inn was built in 1805, and the sea was a distance of fifty yards,
the mean loss of land boing about one yard annually, it was cal-
culated that it would require about seventy years before the sea
would reach that spot, but between the years 1824 and 1829 no
less than seventeen yards were swept away, and a small garden
only, was left between the house and the sea, and when Mr.
Lyell in 1829 visited the place, he found a depth of twenty feet,
(sufficient to float a frigate), where, only forty-eight years ago,
stood a cliff fifty feet high. Mr. Lyell justly remarks, "If once
in half a century an equal amount of change were produced sud-
denly, by -the momentary shock of an earthquake, history would
be filled with records of such wonderful revolutions of the earth's
surface; but if the conversion of high land into deep sea be grad-
ual it excites only local attention." "The flag-staff of the Preven-
tive Service station, on the south side of the harbor, has, within
K

the last fifteen years, been thrice removed inland, in consequents
of the advance of the sea.

Along the whole eastern coast of England, changes similar to
these are going on. In some places by the silting up of estuaries*
land is forming, but not near as much, as is being removed. The
isle of Sheppey, which is a tertiary formation, now about six
miles long, by four in breadth, is rapidly decaying on its north
side, fifty acres of land having been lost within the last twenty
years. To the east of Sheppey stands the Church of Reculver,
upon a cliff of clay and sand, about twenty -five feet high. This-
place was formerly an important military station in the time of
the Romans, and even so late as the reign of Henry VIII, was
nearly one mile distant from the sea.

We here give a view of the Church of Reculver taken in the
year 1781, copied from the Gentleman's Magazine. At this time
the spot had become interesting from the encroachment of the
water. It represents considerable space ns intervening between
the churchyard and the cliff. In the year 1782, the cottage at
the right was demolished ; nearer the church is shown an ancient
chapel now destroyed, and at the extreme right is the Islo of
In the year 1806, a part of the Churchyard with some

CHURCH.

•231

of the adjoining houses was washed away, and the ancient
church with its two lofty spires, a well known land-mark, was
abandoned. The following view of it as it appeared in 1834, is
taken from Mr. Lyell's Principles of Geology, from which the
preceding statement is also derived. This ancient building would

probably, have fallen long since, had not the force of the waters
been checked by an artificial causeway of stones, and large wood-
en piles, driven into the sands to break the force of the waves.

There are good reasons for believing that the coasts of France
and England were formerly united, this is inferred from the iden-
tity of the composition of the cliffs on the opposite sides of the
channel, and also of the noxious animals in England and France,
which could hardly have been introduced by man. This opinion is
advocated by many distinguished geologists, and it is by no means
incredible, that in the course of agfes the sea may have forced its
.passage through. The separation of Friesland, which was once
a part of North Holland, from the mainland, by the action of the

232 THE WORLD.

sea in the thirteenth century, and the formation of a strait of
about half the width of the English channel in 100 years, lends
countenance to this opinion. The inroads of the sea have no
where been more severe than in Holland, and even at the pres-
ent day 12,000 wind-mills are employed to drain the Netherlands
and to prevent at least two-thirds of the kingdom from returning
to the state of bog and morass, and during the past year three
immense steam engines, capable of discharging 2,800,000 tons
of water in 24 hours, have been employed in pumping out and
emptying through the great ship canal, and sea-sluices at Katwyk,
the lake of Haarlem, which by its continual inroads threatened to
inundate Amsterdam on the one side, and Leyden on the other.
In the year 1836, twenty-nine thousand acres of land were com-
pletely overflowed by it. The large lake called the Bies Bach
was formed in 1621, by the sea bursting through the embank-
ments of the river Meuse, overflowing seventy-two villages. Of
these villages no vestiges of thirty-five of them were ever dis-
covered. Since their destruction an alluvial deposit has been
formed parti:,' over their site. The island of Northstraud, which
in the year 1634, contained 9000 inhabitants, and was celebra-
ted for its high state of cultivation, was, on the evening of the
llth of October, in that year, swept away by a flood which de-
stroyed 1300 houses, 50,000 head of cattle, and 6000 men, leav-
ing three small islets, one of them still called Northstrand, which
are continually being wasted away by the sea. Such are some of
the powerful effects of currents and waves in altering, and finally
sweeping away the headlands and islands which at any particular
epoch may have distinguished the line^of coast exposed to their
force; the eastern side of America, along the Atlantic coast is
subject to the same changes. Before leaving this part of our
subject, we will describe that peculiar tidal wave called " the
Bore." This is produced, when the channel of a river, into
which the tidal wave from the ocean is entering, is so narrow that
the water is made to rise suddenly, and thus terminates abruptly
on the side away from the sea, or inland ; precisely like the waves
which break upon a shelving shore. As might be expected, this
phenomenon occurs most powerfully at the time of spring, or high-

THE BORE. 233

est tides. The Bore whfch enters the river Severn is sometimes
nine feet high, and at spring tides rushes up the estuary with ex-
traordinary rapidity. In the Hoogly or Calcutta river, says Ren-
nell, " the Bore commences at Hoogly point, the place where the
river first contracts itself, and is perceptihle above Hoogly town;
and so quick is its motion, that it hardly employs four hours in
traveling from one to the other, though the distance is nearly
seventy miles. The tides of the Bay of Fundy pour twice a day
vast bodies of water through a narrow strait, causing in every
small stream, an immense tidal wave, rising sometimes to the
height of seventy feet. We have already alluded to its rich
alluvial deposits of red marl which have been excluded artificially
from the sea by embankments.

Heretofore we have noticed only the degrading effects of cur-
rents, and tides. It might at first appear that the sediment borne
down by rivers, the formation of deltas, and the silting up of
estuaries, would compensate for the loss by the encroachments of
the sea, this however, is not the case; while in all instances the
new-made land is constantly attracting attention, there are no
boundaries, or great natural land marks, to show where was
formerly the line of coast. The former demand attention by
their presence, the latter are unseen, and therefore lightly esti-
mated; many places where once flourishing cities stood, are now,
not only depopulated, but covered with water to a depth of thirty
feet. There is therefore good reason for believing that the loss
of land by the effects of currents and tides, much more than
counterbalances all deposited in the form of dry land.

The general tendency of these encroachments is undoubtedly
to fill up the bed of the sea, and to finally reduce the surface of
the earth to a uniform level ; and this would ultimt.teh be ac-
complished, but for the counterbalancing force of volcanic or ig-
neous causes, which are continually elevating the surface. If
we had space we might continue to enumerate examples of the
effects of the ocean in destroying the coasts, not only of our own
country, but over the whole world : sufficient however has been
said to give some idea of the importance of these causes of change,
and when hereafter, we allude to immense formations of rock

234 THE WORLD.

strata, imbedding numerous fossils, as the sedimentary deposit of
an ancient ocean, the statement will not appear incredible. The
force of the current of the Amazon extends out into the ocean to
a distance of three hundred miles from its mouth, and when we
remember how long the mud and fine sand remains suspended
even in quiet water, we shall not be surprised to learn that parti-
cles brought down from the interior of South America, are per-
haps deposited in the Mexican Gulf; for where the great equato-
rial current from the coast of Guinea crosses the waters of the
Amazon, it runs with a velocity of four miles an hour. Vast
quantities of drift wood and rubbish are thus carried as far as the
mouths of the Orinoco, and are increasing the island of Trini-
dad. It is the opinion of many distinguished philosophers that
the Isthmus of Suez, which now separates the Mediterranean
and the Red Sea, is a recent formation, it is at least quite certain
that the isthmus is receiving continual accessions on the Medi-
terranean side. The change of coast, the loss of cities, the for-
mation of bays, .the filling up of estuaries and washing away of
islands, important as these changes may be, are nevertheless, of
less moment than the processes going on in the depths of the
sea ; far below, where the waters are never disturbed by the
storms and winds, which lash the surface into fury, a quiet de-
posit is going on, in this are now being imbedded the various
forms of animal existence which are borne down to the bottom of
the ocean. Nor are these all, the wealth of man has gone down,
and lies hurried deep with his bones in the undisturbed strata.
At some distant epoch, when the present ocean bed shall be up-
heaved, perhaps some patient investigator will exhume the fossils,
and moralize upon the eventful change which passeth over all
things. We cannot close this chapter better than with the beau-
tiful language of Mrs. Hemans :

«• The depths have more ! What wealth untold

Far down and shining through their stillness lies !
They have the starry gems, the burning gold,
Won from a thousand royal argosies !

Yet more — the depths have more ! Their waves have roll'd

Above the cities of a world gone by —
Sand hath filled up the palaces of old,

Sea-weed o'ergrown the halls of revelry."

S3XKOUS CAM KS OF CHANGE, 235

CHAPTER V ,.

Volcanic Erupt! us.

" Yon dreary plain, forlorn and wild,
The seat of tie ;olation, void of light,
Save what the glimmering of these flames
Casts pale a d dreadful." Milton.

WE have in the preceding chapters given somewhat in detail
an account of the various aqueous causes of change, now in ope-
ration. We sh? II consider in the present chapter the igneous
causes of chang , or volcanic action ; and in order to economise
the little space v e can allow, will consider them as follows. First,
we shall give a sketch of the geographical distribution of the
chief volcanoe now active, or which have been active within the
historic era. We shall next give an account of the principal
earthquakes, nd other volanic phenomena which have disturbed
the earth's so .-face; and lastly, consider such changes, supposed
to be due to internal igneous agency, as the gradual elevation and
depression of various tracts of country. It would be out of place
for us to discuss at present, the question, whether the interior of
the globe is in a state of fusion, and that the eruptive force of
volcanoes is the occasional liberation of the molten mass, acted
upon by the intense pressure of the superincumbent strata, or by
confined gases and vaj ors ; or whether th© intense heat which
melts masses of rock, causing the most violent convulsions, is
caused by chemical action, i. e. the union of oxygen derived
from water or the air, with the metallic bases of the earths and
alkalies, forming silica, alumina, lime, soda, &c., substances
which predominata in lavas; or whether it be a union of both
these causes. In our own opinion it is neither, but is the result

236 THE WORLD.

of simple mechanical action, produced in a manner we Cannes
here describe.

Volcanoes are found distributed all over the surface of the earth,
though more prevalent in some portions than in others. Many
of the islands in the Pacific and Atlantic are of volcanic origin;
perhaps the majority of them. In some parts of the earth vol-
canoes stand alone, but they are mostly connected with extensive
mountain ranges, extending in a linear direction, and we may
select three distinct regions of subterranean disturbance. The
most extensive is that of the Andes.. Along the whole western
shores of North and South America, extends a lofty mountain
chain, remarkable not only for its position, but also for its
collosal form, the nature of the masses of which it is com-
posed, and of the materials ejected. Along the whole extent o-f
this chain, volcanoes occur, and between the 4Gth deg. of south
latitude to the 27th deg. is a line of volcanoes so uninterrupted
that scarcely a degree is passed without the occurrence of one of
these in an active state ; about twenty now active are enumera-
ted in this space, and doubtless there are very many more which
have been active at a recent period. When we remember how
long a time Vesuvius had remained quiet, before it again renewed
its activity, and overwhelmed the cities of Herculaneum and
Pompeii, we can readily admit that the number of volcanic vents
or craters is much greater than really is now apparent. The im-
mense height of the volcanic mountains of the Andes and Cor-
dilleras is very remarkable, and the craters are all formed by
bursting through porphyritic rock, or igneous unstratified rock,
containing crystals of feldspar. Some of the loftiest summits are
composed of trachyte, a rock of igneous origin, unstratified and
allied to the trap rocks, such as basalt, greenstone, &c. On the
summits are found large quantities of obsidian, or dark green vol-
canic glass, pumice stone,, and tuff' formed out of cinders, and
fragments of lava cemented together.

It appears highly probable that a chain of volcanic vents ex-
tends quite around the globe, in the general direction north and
south. A lofty chain of mountains was discovered by Capl. J.
C. Ross, in the Antarctic regions in year 1841, at a distance of

VOLCANOES. 237

about 800 miles from the south pole. Two of the loftiest of these
were named from his vessels, Mount Erebus, and Mount Terror,
they are each about 12,000 feet in height, and the former is an
active volcano. This range of mountains is probably connected
by a submarine chain with the Andes, first appearing in Terra-
del-Fuego, near which Capt. Basil Hall is said to have witnessed
volcanic eruptions. As we proceed north along the western shore
of South America, we find in Chili, a large number of active
volcanoes, and, what we might reasonably expect, the country
continually disturbed by earthquakes, and abounding in hot
springs. Villarica is the principal of the Chilian volcanoes, it
burns without intermission, and is so high that it may be seen at
a distance of 150 miles. It is s^aid that a year never passes in
this province, without some slight shocks of earthquakes, and
sometimes the most tremendous convulsions occur. As we pro-
ceed northward, we find one active volcano in Peru, but earth-
quakes are so common that scarce a week passes without them ;
and" the names of Lima, and Callao, are familiar in this connect-
ion. Proceeding still farther north, the mountains increase in
height, and furnish by the melting of their accumulated snows,'
and the moisture which is precipitated from the trade winds which
blow over the warm region of Brazil, the sources of that magni-
ficent river, the Amazon, which continually pours such a flood of
water into the Atlantic. When we arrive in the neighborhood of
Quito, in Equador, we find numerous and very lofty volcanoes,
no less than six being embraced in a space of five degrees ; com-
mencing at the second degree of south latitude, and proceeding
to the third degree of north latitude — One of these volcanoes,
Cotopaxi, arises to the height of 18,867 feet, and is the highest
volcanic summit of the Andes. Inform it is a perfect cone, us-
ually covered with an enormous bed of snow. On next page, we
give an engraving which represents this celebrated volcano, which
is higher than Vesuvius would be, if placed on the top of Teneriffe.
The smooth cone, crested with the purest white, shines in tho
rays of the sun with dazzling splendor, and detaches itself from
the azure vault of heaven in the most picturesque manner. At
night, smoke and fire are seen rising from its summit, like a

THE WORLD.

beacon of flame in the regions above. In the course of the last
century it had five great eruptions; in one of these, in January

1803, the snows were dissolved in one night, pouring a deluge of
waters over the plains below. It is averred that the eruptions
of Cotopaxi have been heard at a distance of 600 miles, and
Humboldt states that at 140 miles distance on the coast of the
Pacific, it sounded like thunder. The substances ejected from
these lofty craters are pumice, and cinders, rarely lava currents;
on account of their immense heights, and the consequent enor-
mous pressure which is required to raise a solid molten mass.
Torrents of mud and boiling water are erupted, and subterranean
cavities containing water are opened, and vast quantities of mud,
volcanic sand, and loose stones, are carried down to the regions
below. ; Mud derived from this source, in the year 1797, descend-
ed from the sides of Tunguragua, a volcano in the neighborhood
of Cotopaxi, and filled valleys 1000 feet wide to the- depth of 600
feet. In these currents and lakes are thousands of small fish,
which, according to Humboldt, have lived and multiplied in the
subterranean lakes. So great a quantity of these fish were erupt-
ed in 1690, from the volcano of Imbaburu, that fevers were caused
by effluvia arising from the putrid animal matter. Sometimes,after
successive eruptions, the undermined walls of the mountain fall,
and it becomes a mass of ruins, such was the fate of L'Altar, which
was once higher than Chhnborazo, but according to the tradition
of the natives, before the discovery of America, a prodigious
eruption took place which lasted eight years and broke it down.

VOLCANOES. 239

In 1693 another lofty volcano fell, with a tremendous crash.
Proceeding farther north, we find tl ree active volcanoes in the
province of Pasto, and three likewise in that of Popayan. Pass-
ing on, across the isthmus of Darien into Guatemala, and Nicar-
agua, no less than twenty-ono active /olcanoes are found between
the tenth and fifteenth degrees of noi th latitude. Among these
is an enormous mountain called the volcano of water (de Agua),
at the base of which in 1527, the old city of Guatemala was built
A few years afterward, a most formidable aqueous eruption burst
forth, which overwhelmed the whole city, and buried in the ruins
most of the inhabitants. Appalled by this disaster, the Spaniards
built another city, New Guatemala, in another situation, farther
from the mountain. Among other splendid buildings it contained
a Cathedral more than 300 feet long, and one of its nunneries had
more than 1000 persons in it. After a series of dreadful shocks,
and volcanic eruptions, this beautiful city shared the fate of the
former, and was reduced to a heap of luins in 1775. We have
now traced this volcanic chain for a distance of nearly 5000 miles
from south to north, arriving at the high (able land of Mexico,
which is the middle part of the great chain of mountains called
the Andes or Cordilleras in the south, and the Rocky Mountains
in the north. This table land is from 6000 to 8000 feet in height,
thus rivalling Mount St. Bernard and other remarkable summits
in the eastern continent. This table land is not an interval be-
tween opposite ridges, but is the highest part of the ridge itself. In
the course of it, isolated peaks occur, the summits of which reach
the elevation of perpetual snow. It is somewhat remarkable,
that a chain of volcanic mountains traverses this table land at right
angles, which, with few interruptions, seems almost as smooth as
the ocean, to a distance of 1500 miles north. Hence while com-
munication with the City of Mexico is very difficult from either
sea coast, there is nothing to prevent wheel carriages from run-
ning along the top of this mountain chain to Santa Fe. The
volcanic mountains, are five in number, and run at right angles;
commencing with the most eastern, we have Tuxtla, a few miles
west of Vera Cruz ; Orizava, the height of which is 17,370 feet,-
Popocatepetl 500 feet higher, and shown in the engraving below.

240 THE WORLD,

This is the highest mountain in Mexico, and is continualfy burn-
ing. The two others lie on the western side of Mexico, and are

called Jorullo and Colirna, the latter being 9000 feet in height.
We shall have occasion to speak of Jorullo and its eruptions
hereafter. It is somewhat remarkable that these five volcanoes
now active, are connected by a chain of intermediate ones, which
undoubtedly have been so at some remote period, and that if the
line of volcanic vents be prolonged in a westerly direction, it will
pass through a group of volcanic islands, called the isles of Rev-
illagigedo. Proceeding north of Mexico, another chain of moun-
tains running parallel with the Rocky Mountain chain, com-
mencing in the peninsula of California, runs as far north as the
50th deg. of north latitude, where it ends near the Rocky Moun-
tains. In the peninsula of California there are three, or accord-
ing to some accounts, five active volcanoes. In the Rocky
Mountain chain from Mexico north, no active volcano occurs,
but the whole country, says Mr. Parker, " from the Rocky Moun-
tains on the east and Pacific Ocean on the west, and from Queen
Charlotte's Island on the north to California on the south, presents
one vast scene of igneous or volcanic action. Internal fires ap-
pear to have reduced almost all the regular rock formations to a
state of fusion, and then, through fissures and chasms of the
earth, to have forced the substances which constitute the present
volcanic form. Such has been the intensity aud extent of this

ROCKY MOUNTAINS. 241

ag-ency, that mountains of amygdaloid and basalt have been
thrown up ; and the same substance is spread over the neighbor-
ing plains, to what depth is not known ; but from observations
made upon channels of rivers and the precipices of ravines, it is
evidently very deep. The tops of some mountains are spread out
into horizontal plains, some are rounded like domes, and others
terminate in conical peaks and abrupt eminences of various mag-
nitudes, which are numerous, presenting themselves in forms
resembling pillars, pyramids, and castles. There are several
regularly formed craters ; but these, presenting themselves in
depressions or in cones, are rendered obscure by the lapse of
time." Mr. Parker also states that nearly all the rocks of this
region are amygdaloid, i. e. a trap rock in which agates and mine-
ral substances are scattered about like almonds in a cake; basalt,
lava, and volcanic glass, or obsidian. The Rocky Mountain chain
extends north to the Arctic ocean, skirts along its coast, and is
probably connected subterraneously, with the volcanic band which
we shall presently describe, extending from the Aleutian Isles, or
extremity of the peninsula of Alaska, in Russian America, to the
Molucca Isles. The whole shore of western America, from the
peninsula just mentioned to Vancouver's Islands, presents a bold
and awful aspect, being bordered with mountainous steeps, cov-
ered with primeval forests, and containing two of the most
elevated peaks in the northern part of America, Mount St. Elias,
18,000 feet, and Mount Fairweather, 14,913 feet above the ocean.
Passing from the peninsula of Alaska, we find the volcanic chain
extending through the Aleutian or Fox Islands, which are a long
and numerous group extending nearly to Kamschatka. From al-
most every island, steep and lofty peaks arise, and from many,
volcanic fire is discharged. In 1795 an island was thrown up and
added to this group, by an eruption from beneath the sea, and con-
tinued 1o increase, till in 1807 it measured twenty miles in circuit.
Throughout this whole tract, earthquakes of the most terrific de-
scription occur. The line of volcanic craters continues through
the southern extremity of Kamschatka, where are seven active
volcanoes, which in some eruptions have scattered ashes to im-
mense distances. The chain is prolonged through the Kurile

•242 THE WORLD.

islands, where a train of volcanic mountains exists, nine of which
are known to have been in eruption ; and elevations of the bed
of the sea from earthquakes have occurred several times since
the middle of the last century. The line is next continued through
the Japanese group, which contains a number of active volcanoes
and is continually liable to earthquakes. Proceeding southward,
the chain is continued through the islands of the East Indian
Archipelago. Mountain ranges of a volcanic character traverse
almost all these, some rising upwards of 12,000 feet in height.
In Sumatra, four volcanoes occur, and also several in Java. The
largest of the Mollucca group, Celebes, contains a number of
volcanoes in a state of activity, and one of the most terrible erup-
tions ever recorded happened on the island of TSumbawa another
of this group. Here the chain branches off eastward and west-
ward, passing to the west through New Guinea, New Britain the
Solomon group,and the New Hebrides, thence through the Friend-
ly and Society Islands nearly east. Indeed the Pacific Ocean in
the equatorial regions seems to have been one vast theatre of ig-
neous action, its innumerable archipelagos being composed of
volcanic rocks, or coralline limestones> with active vents here
and there. To the westward, the chain passes through Borneo,
and Sumatra, to Barren Island in the Bay of Bengal. From
Java southward, the chain may be traced along the coast of New
Holland and Van Diemens land, and thence probably is a sub-
marine connection with Freeman's Peak, in the Ballerny Isles, on
the Antarctic continent. Still farther south we have the chain
extending along Victoria land, between 80° and 70° of south
latitude, connecting with Mounts Erebus and Terror before men-
tioned. Another great chain of mountains runs nearly east and
west from the shores of the Caspian sea to the Atlantic, passing
through Turkey, Austria, Italy, Switzerland, France, and Spain.
The whole region along this chain, which sends off many lateral
branches, is subject to earthquakes and other volcanic phenomena;
the well known volcanoes Etna, and Vesuvius, are a part of this
chain. In addition to the volcanic chains we have named, there
are some cases of isolated volcanic action, such as Mount Hecla
in Iceland, and the volcanoes of Madagascar.

IGNEOUS CAUSES OF CHANGE. 243

CHAPTER VII.

Volcanic Eruptions.

" But, even then, the ground

Heaved 'neath their tread — the giant turrets rocked,
And fell : and instantly black night rushed down,
And from its bosom burst a thunderous crash
Stunning and terrible." Wm. Howitt.

THE number of active volcanoes, and solfataresor vents, from
whieh sulphureous and acid vapors and gases are given off, is
about 305; of these, 196 are in islands, and the other 109, are on
continents. It is however, a remarkable fact that a majority of
them are located near the ocean, or large bodies of water; and
even submarine volcanoes are not of unfrequent occurrence. Be-
sides the volcanoes now in action, there are many undisputable
extinct volcanoes, L e., volcanoes which at some period of the
earth's existence, but before the historic era, have been in the
state of active eruption. In no country is there better evidence
of this than in France. There are in the districts of Auvergne,
Vivarais, and Cervennes, more than a hundred conical moun-
tains, composed of lava, scorise, and volcanic ashes heaped up,
many of them still retaining their ancient craters, and in some
cases currents of lava may be traced to great distances. The
evidences of -volcanic action in the Rocky Mountains we have
already alluded to.

How long a period of repose may be necessary to constitute an
extinct volcano, is of course undetermined. We include as such,
those which show indubitable evidence of former activity, but
which have not had eruptions within the historic era. Tt is by no
means necessary that volcanoes, to be considered active, should
incessantly emit flames, they may remain for ages choked up,

244 THE WORLD.

and again suddenly resume all their former character. Thus
Vesuvius, which had been extinct from time immemorial, al-
though its crater was clearly formed by some ancient volcanic
action; suddenly rekindled in the reign of Titus, and buried the
cities of Herculaneum, Pompeii, and Stabiae, 'under its ashes.
After this effort it again slumbered, the memory of its former
power faded away; trees and grass grew on its summit, when sud-
denly in 1630, it renewed its action. At this time, the crater,
according to the' account of Bracini, who visited Vesuvius not
long before the eruption of that year, "was five miles in circum-
ference, and about a thousand paces deep; its sides were covered
with brushwood, and at the bottom there was a plain on which
cattle grazed. In the woody parts wild boars frequently harbored.
In one part of the plain, covered with ashes, were three small
pools, one filled with hot and bitter water, another salter than the
sea, and a third hot but tasteless." Suddenly, in December 1530,
these forests and grassy plains were blown into the air, and their
ashes scattered to the winds ; seven streams of lava poured at the
same time from the crater, and overflowed several villages at the
foot, and on the side of the mountain; since that time there has
been a constant series of eruptions. Etna after slumbering for
ages, burst forth and destroyed the city of Catania; the accounts
of its previous eruptions having been considered by the inhabit-
ants as fables.

Subterranean noises, and the appearance, or increase of smoke,
are the first symptoms of approaching volcanic action. This is
soon accompanied by a trembling of the earth, and louder noises;
the air darkens, and the smoke, thick with fine ashes, increases.
The stream of smoke rises like an immense black shaft, high up
into the air, and arriving at a point where its density is the same
as the atmosphere, spreads out like a vast umbrella, overshadow-
ing the whole country with its dark gloom. Such was the ap-
pearance as described by Pliny, the Elder, who witnessed the
eruption of Vesuvius which overwhelmed Pompeii, in A. D. 79.
Occasionally, lightning flashes illuminate the dark cloud, and
streams of red hot sand, like flames, shoot up into the sky, at-
tended with louu explosions. The shocks, and tremblings of the

VOLCANIC ERUPTIONS. 245

ground, increase, and the whole neighborhood gives evidence of
the immense pressure which is being exerted; presently the mol-
ten lava, is by the immense force raised into the crater, and fill-
ing- it up, or melting its passage through the side, flows in a red
hot stream down the flanks of the mountain in a river, or rather
a torrent of fire. The eruption is sometimes attended with enor-
mous currents of water, mud, and noxious gasses. A period of
rest succeed?, generally of short duration; again the same phe-
nomena are repeated, and thus the action continues fo? a varia-
ble length of time, until finally, the crisis is past and the volca-
no resumes its original quiet.

The substance:? principally ejected by volcanoes are smoke,
ashes, sand, scoriae, volcanic glass and bombs, and masses of
rock. The ashes thrown out in volcanic eruptions appear to be
the substance of the lava very finely divided. These ashes are
raised so high that they are carried by the winds to almost incred-
ible distances. Ashes from the eruption of a volcano in St. Vin-
cent in 1812, were carried twenty leagues, and fell in Barbadoes,
and from the eruption of Hecla in 1766, they fell in Glaumba, a
distance of fifty leagues; and it is said that ashes from Vesuvius
have fallen in Constantinople, a distance of four hundred and
fifty leagues. The volcanic saud, is composed of particles some-
what larger, but of the same character as the ashes, being commi-
nuted particles of lava, and forming a principal part of the eject-
ed matter pf volcanic eruptions. Scoria}, and pumice stone, are
caused by the gasses, which bursting through the melted lava,
carry up with them certain portions into the atmosphere, which
becoming consolidated, present the appearance so well known
under the name of slag and cinders. Volcanic glass or obsidian,
is often ejected in small melted masses ; sometimes, the winds
catching this, spin it into the finest threads. We have seen many
specimens of this kind irom the eruptions of Kirauea, in the
Sandwich Islands. Among the extinct volcanoes of France,
drops, tears, and elongated spheroids, being drops of lava thrown
out, and consolidated in the air, are continually found, they are
called vdlcanic bombs. Masses of rock are always ejected in
severe eruptions; in many cases these are undoubtedly torn off

246 THE WORLD.

from the interior of the mountain by the immense power exerted;
and they are ejected without having been melted. A stone of
109 cubic yards in volume, was ejected by Cotopaxi, and thrown
to a distance of nine miles.

The force which is exerted, to cause the eruptions of lavas, or
liquid masses of stone, is almost beyond belief, varying according
to the height of the crater. The force of Vesuvius in some of
its eruptions has been estimated as equivalent to a pressure of at
least 6000 pounds on every square inch ; and of Etna, about 17,-
000 pounds on the square inch ; the amount of force requisite to
raise melted lava to the crater of Cotopaxi, would be at least 30,-
000 pounds on each square inch. The masses of melted matter
ejected, are equally incredible ; the amount thrown out by Vesu-
vius in 1737, was estimated at 11,839,168 cubic yards, and about
twice this amount in 1794. In 1660, the mass of matter disgorged
by Etna, according to Mr. Lyell, was twenty times greater than
the whole mass of the mountain, and in 1669, when 77,000 per-
sons were destroyed, the lava covered 84 square miles. The
greatest eruption of modern times, was from Skaptar Jokul, in
Iceland, in 1783. Two streams of lava, one fifty miles long and
twelve broad, the other forty miles long, and seven bioad ; both
avaraging 100 feet in thickness, and sometimes 500 or 600 feet,
flowed, in opposite directions, destroying twenty villages, and
9000 inhabitants. The velocity with which the melted lavas move
varies with the slope of the mountain, and the nature of the
ground, as well as the viscidity and quantity of the lava. In
general, a velocity of 400 yards an hour is considered quick, al-
though sometimes the stream flows much quicker; in flat grounds
it sometimes occupies whole days in moving a few yards. Lavas
cool extremely slow, the surface becomes soon consolidated, and
is such a poor conductor of heat, that the interior remains heated
and melted for whole years ; and currents have been mentioned
which were flowing ten years after emerging from the crater,
and they have been seen smoking twenty years after an eruption
of Etna. The currents of lava thrown out by successive erupt-
ions being placed one above the other, alternating with beds of
sand, scoriee, &c., form a series of inclined beds that give rise to
the cone of the mountain.

HERCULANEUM AND POMPEII. 947

Having now described the principal phenomena attending vol-
canic eruptions, and the nature of the erupted materials, we pro-
ceed to describe briefly %ome of the more remarkable effects of
volcanic agency. Southern Italy, being inhabited by a cultivated
people, and in very early times the scat of literature and science,
as well as the grand European seat of volcanic action, claims
particular attention. Here are three active volcanic vents. Ve-
suvius near Naples, Stromboli on the Lipari Isles, and Etna in
Sicily. The whole region is subject to earthquakes, and abounds
in thermal springs impregnated with calcareous matter, and from
certain fissures deleterious gasses and sulphureous flames issue.
The ancient name of Vesuvius, was Somma; it is now a broken
and irregular coue about 4000 feet in height. We have already
given the description of this mountain as it appeared before the
eruption of 1631. It is said that its cone was formerly of a regu-
lar shape, with a flat summit, containing the remains of an an-
cient crater, and covered with wild vines. After a slumber of
ages, Vesuvius in the year 63, began to exhibit some symp-
toms of internal agitation, by an earthquake which occasioned
considerable damage to some of the neighboring cities. It is
somewhat remarkable that the memorials of this convulsion
have beenfljreserved, and made known, through the agency of
another more terrible convulsion, that of August 24th in the year
79, when a tremendous eruption occurred, and the pent up melt-
ed materials of the volcano burst out, overwhelming three cities
and many of their inhabitants. Two of these cities, Herculane-
umt and Pompeii, have since been exhumed. The former was
fir&t discovered ; but they had long been forgotten. The eruption
which destroyed these cities was witnessed by both the Plinys,
and indeed, it was from his too venturesome curiosity to observe
this magnificent natural exhibition, that the elder Pliny lost his
life, being suffocated by the sulphureous vapors. The account
which Pliny the Younger has left of this eruption, is very full
and minute ; but he makes no allusion to the overwhelming of
the two cities. In 1713, Herculaneum was accidentally discov-
ered, having been buried in lava for 1634 years. Some fiag-
ments of marble were observed in sinking a well; and subse-

iJ4e THE WORLD.

quently a small temple, and some statuary. The city of Portiei
is built upon the lava directly above Herculaneum, and this has
prevented extensive excavations. Pompdi was enveloped in ashes
and cinders, and has been opened to the light of day. Both these
cities were sea-ports, and Herculaneufri is still near the shore,
but Pompeii is at some distance, the intervening land having been
formed by volcanic agency. In both these cities inscriptions were
found in the temples commemorating the event of their rebuild-
ing after having been overthrown by an earthquake sixteen years
before, A, D. 63. Thus, in the language of Bulwer, "After nearly
seventeen centuries 'had rolled away, the city of Pompeii was dis-
intered from its silent tomb, all vivid with undimmed hues ; its
walls fresh as. if painted yesterday; not a tint faded on the rich
mosaic of its floors; in its forum the half-finished columns, as
left by the workman's hand ; before the trees in its gardens the
sacrificial Iripod; in its halls the chest of treasure; in ite baths the
strigil; in its theatres the counter of admission; in its saloons the
furniture and the lamp; in its triclinia the fragments of the last
feast; in its cubicula the perfumes and rouge of faded beauty;
and everywhere the skeletons of those who once moved the
springs of that minute, yet gorgeous machine of luxury and of life."

We here present a view of Vesuvius from Sir Wrn. Gells Pom-

ERUPTIONS OF ETNA* 249

peiana, showing the site of Pompeii, and the course of the river
Sarnus. Among the ruins of these cities many valuable relics
have been found. The^various utensils and works of art, almost
as fresh as though buried but for a day. Rolls of papyri, with
little tickets attached, denoting their contents; loaves bearing the
stamp of the baker; linen, and fish-nets, and fruits, all preserved
along with sculptures, and paintings, and unharmed for near 2000
years. No doubt, many valuable manuscripts will be found when
Herculaneum is more excavated, which will restore to us the lost
writings of the ancient philosophers. The eruption of Vesuvius
which buried these cities, is so well known we need not dwell
longer upon it here ; we pass to consider next the eruptions of
Etna.

The cone of Etna, which has been so minutely and well de-
scribed by Mr. Lyell, is entirely composed of lavas, and rises
majestically to an altitude of two miles, the circumference of its
base being about 180 miles. At the base of the mountain is a
delightful, well cultivated and fertile country, thickly inhabited,
and covered with olives, vines, corn, fruit trees, and aromatic
herbs. Higher up, upon the mountain side, a woody belt encir-
cles ii, forming an extensive forest of chesnut, oak, and pine,
with some ^royes of cork and beech, and affording excellent pas-
turage for flocks; still higher up, is a bleak barren region, cover-
ed with dark lavas and scoritE. Here, from a kind of plain arises
the cone of Etna to the height of 11,000 feet, and continually
emits sulphureous vapors ; its highest points being covered with
eternal snow. Over the flanks of Etna a multitude of minor
cones aro distributed, particularly in the woody tract, caused by
form or eruptions, but the grandest feature of Etna is the Val del
Boce, which is a vast excavation, as though a portion of the
mountain had been removed on the side towards the sea, forming
a vast plain, five miles across, encircled by minor volcanic cones,
and enclosed on three sides by precipitous rocks from 2000 to
3000 feet high. This vast plain has been repeatedly deluged by
streams of lava, and presents a surface more rugged and uneven
than that of the most tempestuous sea. From the earliest period
of history, Etna appears to have been active, but the first great

250 THE

eruption of modern times occurred in the year 1669. Previous
to this eruption, an earthquake occurred which levelled many of
the villages and towns in the neighborhood, and was attended
with an extraordinary phenomenon. A fissure, six feet broad and
of unknown depth, opened with a loud crash in the plain of St.
Lio, and run to within a mile of the summit of Etna, in a some-
what tortuous course. Its direction was from north to south, and
it emitted a most vivid light. Five other parallel fissures of con-
siderable length, afterwards opened, one after another, attended
with similar phenomena. Mr. Lyell supposes that these were., at
the time, filled with melted trap or porphyry* forming vertical
dikes. During this eruption a minor cone known by the name
of Monti Rossi, was formed, about 450 feet high, which poured
out a lava current, which after overflowing some fourteen towns
and villages, some having a population of 3000 to 4000 inhabit-
ants reached the city of Catania, ten miles distant from the vol-
cano. Walls sixty feet high had been purposely raised to pro-
tect the city in case of eruption. Against this rampart the lava
flowed, and accumulated, until in a fiery cascade, it poured over
the top, and destroyed a part of the city. The wall still remains,
and the curious traveler may see the lava curling over the top,
by means of excavations since made, as if still in.the very act of
falling. This lava current moved a distance of fifteen miles be-
fore it reached the sea. One of the towns overflowed during this
eruption was Mompiliere, a part of which, was afterwards un-
covered with incredible labor, and the gate of the principal
Church was reached at a depth of thirty-five feet, and several ar-
ticles in good preservation were extracted, among these were a
hell, a statue, and some coins. It is said that the heat of this lava
current was so intense eight years afterwards, that it was impos-
sible to hold the hand on some of the crevices formed by the
cracking of its crust upon cooling. In the year 1828 a remarka-
ble discovery of a glacier covered by a lava stream was made,
after having been concealed for ages. In that year, from the pro-
tracted heat of the season, supplies of ice at Catania and the ad-
joining parts of Sicily, failed entirely, and great distress was felt
at the want of a commodity which they had learned to regard as

OF HJbtL.i, 261

a necessary of lii'e; accordingly search was made at a place which
had long been suspected as being a glacier covered with lava, at
the foot of the highest cone, when for several hundred yards a
solid bed of ice, so hard that it was quarried with the utmost dif-
ficulty was found, covered entirely by lava.

We now turn to Iceland, an island subject to tremendous vol-
canic eruptions, and containing several volcanic mountains*
Mount Hecla has been in continual activity, with but a short oc-
casional rest, from the earliest period ; its eruptions have lasted
sometimes as long as six years without cessation. In the year
1783 two great eruptions happened, about a month apart, one
about tlie middle of May, and the other the llth of June. The
first was a submarine volcano which threw up so much pumice
that the ocean was covered to a distance of 150 miles. A new
island was formed, consisting of high cliffs, within which, fire,
smoke, and pumice, were emitted from several different parts.
This island, which, was claimed by his Danish Majesty and called
.Nyoe, or new-island, was destroyed before a year, by the sea,
leaving nothing but a reef of rocks from five to thirty fathoms
under water. The eruption of June llth was on the island, a
distance of 200 miles from Nyoe, when the crater of Skapta Jokul
emitted a torrent of lava which flowed down into the river Skap-
la, and entirely dried it. This river was about 200 feet in breadth
and from 400 to 600 feet deep, running between high rocks, not
only was this great bed filled with the lava current, but, rising
higher, it overflowed the neighboring fields; after filling the bed
of the river, the lava current flowed into a deep lake, which was
in a short time completely filled; still flowing on, it penetrated
die caverns which had been formed in the older lava, and melted
down portions of it, and in some cases where it could not get
vent, it blew up the rock with a tremendous explosion. On the
18th of June another ejection of melted lava, flowed with great
swiftness down the mountain, over the bed of the former erupt-
ion. By the damming up of tho rivers, and lakes, and conse-
quent displacement of water, many villages were completely de-
stroyed and overwhelmed. This lava current, after flowing for
several days, was finally precipitated down a tremendous catar-

252 THE WORLD.

act called Stapafoss, filling up a profound abyss which the water
had been hollowing out for ages. On the 3rd of August another
tiood of lava was poured forth which flowing in an entirely new
direction, as all the other channels were choked up, filled the bed
uf the river Hverfisfliot, occasioning great destruction of property
and life. The eruption continued for about two years, and eleven
years afterwards when Mr. Paulson visited the island, he found
columns of smoke still rising from parts of the lava, and several
rents filled with hot water. Iceland at this time contained about
50,000 inhabitants, more than 9000 of whom perished during
these eruptions, besides vast numbers of cattle; and twenty villa-
ges were destroyed, not enumerating those inundated by 'water.
The great loss of life was owing not only to the vast amount of
noxious gasses emitted, but to the famine caused by the showers
of ashes throughout the island, and the desertion of the coasts by
the fish. The two branches of lava which flowed during this
eruption, in opposite directions, were, the one fifty, the other forty
miles in length, and their average depth 100 feet. The extreme
breadth of the current which filled the bed of the river Skapta,
was twelve miles, the extreme breadth of the other was about
seven miles. The eruptions of Hecla, six of which hare occurred
in one century, seern now to be suspendad, but the whole island
presents abundant evidence of volcanic action. We have already
alluded to the phenomena of the Geysers, or hot springs; beside
these there are no less than six volcanic vents, emitting flame
and smoke. The island of Nyoe thrown up just bdfore the great
eruption of Skapta Jokul, is by no means the only instance of a
volcanic island occurring at a recent period. In the year 1831, a
volcanic island arose in the Mediterranean, about thirty miles off
the south-west coast of Sicily, in a spot which had been found by
Capt. Smyth to be more than 600 feet in depth. On the 23th of
June, Sir Pultney Malcolm, in passing over the spot with his ship
felt the shock of an earthquake, as if he had struck on a sand
bank, this was about a fortnight before the eruption occurred.
About the 10th of July a Spanish Captain who was passing near
the place, reported that he saw a column of water, like a water
spout, about sixty feet in height, rising from the sea; this was

VOLCANIC ISLAND. 253

succeeded by a cloud of steam, and at length, on his return, the
l?th of July, he found a small island about twelve feet high, with
a crater in its centre, ejecting scoriae, ashes, and volumes of va-
por; and the sea around was covered with floating cinders, and
dead fish. This island continued increasing in dimensions until
it reached an elevation of 200 feet, and was about three miles in
circumference, having a circular basin full of hot water, of a din-
gy red color. The eruption continued with great violence nearly
a month, and the island attained its greatest dimensions about
the 4th of August, after which it began to decrease by the action
of the waves, and on the 29th of September, its circumference
Was reduced to about 700 yards. Its appearance at this Jime is
represented in the accompanying wood cat, which is from a sketch

by M. .Toinville, who visited this island in September 1831. It
has now entirely disappeared, and a dangerous shoal remains
about eleven feet underwater. This is not the only volcanic island
of recent formation, for in the year 1812, off the coast of St.
Michael's one of the Azores, an immense volume of smoke,
thick with ashes and stones, was observed to burst forth, by Capt.
Tillard, of the Royal British Navy, at a spot where before, the

"254 THE WORLZJ.

water was thirty fathoms in depth. At the same time the cliffs?
of St. Michael were shattered by an earthquake. This island ,
which was called Sabrina, from the ship of Capt. Tillard, rose
200 feet above the water, but soon after disappeared being corn-
posed almost entirely of ashes and cinders. We have already
noticed the Aleutian islands, as the theatre of volcanic action. In
the year 1806, a new island, which still remains, and consists of
solid rock, about four miles in circumference, was thrown up from
the bottom of the sea; and in 1814, another of the same charac-
ter, but much larger, being 3000 feet in height, was added to the
same group. We might enumerate many other islands formed by
volcanic agency did our limits permit, but we hasten to consider
next trie volcanoes of South America.

In noticing the great chain of mountains which runs along the
western coast of America, we alluded to the five volcanic vents
in about the parallel of the City of Mexico, arranged in a line at
right angles nearly to the general direction of the mountainous
chain. One of these volcanoes, that of Jorullo, is particularly
remarkable, being the product of an eruption which occurred in
1759, and lasted about nine months. The volcanoes of Tuxtla,
Orizava, and Popocatapetl, are on the eastern side of Mexico, the
latter is continually burning, but seldom emits anything more
than smoke and ashes. At the west of the city, are the volcanoes
of Colima, and Jorullo, the former about 9000 feet in height, and
emitting smoke and ashes; between the city and this volcano lies
the plain of Jorullo, in which a crater was formed in 1759. In
that year according to Humboldt, who has minutely described the
phenomena, in the month of June, a subterranean noise was
heard in the district of Jorullo; hollow sounds of the most fright-
ful nature, which were accompanied by frequent earthquakes,
succeeded each other for from forty to fifty days ; causing great
terror to the inhabitants of that district. From the beginning of
September everything seemed to announce the complete re-
establishment of tranquility, when, in the night of the 28th and
29th, the horrible subterranean noise recommenced. The af-
frighted Indians fled to the mountains, soon a tract of ground,
from three to four square miles in extent, began to swell like waves

tfctTPTION OF JORDLLO; 255

of the sea, and finally rose up in the shape of a bladder, then
opened, and fragments of burning rocks accompanied with flames,
were thrown to an immense height. The rivers Cuitimba and
San Pedro, which watered this plain, formerly cultivated with
fields of cane and indigo, precipitated themselves into the burn-
ing chasms. Hundreds of small cones from three to ten feet
high, called by the natives hornitos issued from the smoking plain,
and six large volcanic cones wer*.- formed, the smallest three hun-
dred feet high, and the largest, which is the present volcano of
Jorullo, 1600 feet in height. It is continually burning, or rather
now sending forth sulphureous gasses, and has thrown up from
its north side immense masses of basaltic lava, with fragments of
granitic rocks. Below we give an outline of this celebrated vol-

canic mountain, a is the summit of Jorullo, b c inclined plane,
sloping at an angle of 6° from the base of the cones. This
eruption occurred at a distance of 150 miles from the sea-coast,
and is somewhat remarkable on this account, all other active vol-
canoes being near the sea. The eruptions of rnud, however,
and balls of decomposed basalt, and especially strata of clay,
se*em to indicate that subterraneous water had no small share in
producing this phenomenon. Humboldt visited the country more
than forty years after the eruption, and found the elevated mass
of the former plain, shown by the slope b c in the preceding out-
line sketch, still hot enough in some of the fissures at a depth of
a few inches, to light a cigar. The hornitos have now ceased to
emit steam, or smoke, and the central volcano is itself almost
extinct, the plain and slope of the mountain is covered with a
luxurious vegetation, and the memory of' the former terrific con-
vulsions seems almost forgotten.
We have How given an account of the most celebrated volca-

356 THE WOULD.

noes, and the effects produced by their erupti-ms. When we bear
iu mind that during the earlier periods of the earth's existence,
volcanic action was much more general and severe than at pre-
sent, we will be at no loss for a sufficient cause to produce most '
of the upheavings, and contortions of strata, observed on our
globe. In some parts of the world, whole districts are composed
of extinct volcanoes, which even yet have not wholly ceased to
emit deleterious gasses, and the traces of their former and pow-
erful action are seen in every country.

We have not discussed at all, the causes which produce volca-
nic eruptions ; these are not yet satisfactorily determined ; and a
great diversity of opinion still exists among philosophers. It will
be seen upon referring to the diagram, (page 178), that the com-
parative height of the loftiest mountains, is but as a minute grain
of sand on a large globe, and that such slight changes from the
general level of the surface may be produced by causes compara-
tively small.

IGNEOUS CAUSES OF CHANGE. 257

CHAPTER VIII.
Earthquakes.

" Of chance or change, oh! let not man complain ;
Else shall he never, never, cease to wail ;
For from the imperial dome, to where the swain
Rears his lone cottage in the silent dale,
All feel the assault of fortune's fickle gale.
Art, empire, earth itself, are doom'd ;
Earthquakes have raised to heaven the humble vale;
And gulfs the mountains' mighty mass entomb'd;
And where the Atlantic rolls, wide continents have bloom'd."

Beattie.

IN the present chapter we shall briefly describe some of those
remarkable convulsions which from time to time have caused the
crust of the earth to heave like the waves of the ocean, and to
gape open in many places, suddenly engulphing cities and their
inhabitants, or deluging whole tracts of country by the upheaved
waters. These phenomena, which are supposed to be caused by
immense evolutions of steam, and other vapors, or gasses, under
an intense pressure, which is only relieved by a volcanic erup-
tion, or an opening of the earth, constitute the most terrible warn-
ings, which reminds us of the instability of all things. The evi-
dences of mighty change which the philosopher sees in each up-
heaved hill of granite, and dike of trap, or in the formation of
contorted strata may read to him a lesson, which, if rightly un-
derstood, will teach him to look far from his present abode, for
the unchangable world; but the careless observer, who builds his
cottage on the side of a volcanic cone, and feeds his flocks with-
in its crater, needs the awful sound of subterranean thunder, and
the rocking of the plain, to convince him that the neglected tra-
ditions of former calamities, were not all a fiction.

258 WORLD.

There is something startling in the idea tha,t our earth, or rath-
er its crust, is perhaps but a few hundred miles in thickness, or
in other words, that our globe is a hollow ball of no very great
dimensions. It is a well established proposition that, under influ-
ence of the attraction of gravitation, a body, or a mass of matter,
placed any where within a* hollow globe, as at a or b, (see the^ dia-
gram below), will remain at rest wherever it may be situated.

Hence, whether the interior of the hollow globe be molten or
not, the mass will not be displaced, or in other words, it will have
no tendency to move, unless operated upon by other force than
the attraction of gravitation.

The name earthquake has been given to those convulsions of
supposed igneous origin, which cause the surface of the earth to
heave, or undulate, producing rents, and generally precursing the
eruption of some volcano, • The region of violent earthquakes,
is generally the site of some active volcano, and the paroxysms
of an earthquake, are generally relieved by a volcanic eruption,
Thus, during the earthquake which overturned Lima in 1746, and
which was one of the most terrible which has been recorded, four
volcanoes opened in one night, and the agitation, of the earth
ceased. The phenomena attending earthquakes are various,
sometimes there is but a slight undulatory movement, barely suf-
ficient to cause the lighter articles upon the surface to change
places. Persons unacquainted with* the phenomena of earth-
quakes, suppose themselves seized with a sudden giddiness. Of-
ten the first shocks are of this light character, then gradually be-

PHENOMENA ATTENDING EARTHQUAKES. 259

come more severe, and frequeni, so that the movement of the
earth is apparent to the most inexperienced. It is now that the
subterranean thunder is heard, and the walls of buildings begin
to gape open, and close, rendering it exceedingly dangerous to re-
main in them. The fields and tho mountains, at such times, af-
ford no secure shelter, the former are often rent asunder, open-
ing enormous fissures, which engulph thousands, and then close
again, while the n»ountains are rent, and slide down into the val-
leys, damming up the rivers and lakes, and causing tremendous
inundations. At such times, the bed of the ocean appears as un-
stable as the dry land; vast waves, sometimes fifty or sixty feet
in height, are rolled along the coast, and then retire, leaving the
whole shore dry. Ships at sea, often experience these extraor-
dinary movements, even at a distance of 250 miles from land,
seeming as violently agitated as though grating over a ledge of
rocks, and suddenlv striking on the ground, and often with such
violence as to open the seams of the vessel. The duration of a
single shock rarely exceeds half ^second. In this short space of
time, thousands of human beings have found a common grave,
and whole cities have been swallowed up. The interval whicb
•elapses between successive shocks is variable; sometimes they
succeed with considerable rapidity, and at other times happen
after an interval of months, or even years. The first shock is
not always the most violent, though in some particular regions of
country, Syria, for example, the first catastrophe is always the
most destructive; generally however, the second shock is mow
violent The extent of country agitated by some great earth-
quakes is very remarkable; thus the momentary upheaving of the
bed of the ocean, during the earthquake of 1755, which destroy-
ed Lisbon, caused the sea to overflow the coasts of Sweden,
England, and Spain, and the islands of Antigua, Barbadoes, and
Martinique, in America; at Barbadoes, the tide rose nearly 18
feet above high water mark, and the^ water was brack as ink from
the presence of bituminous matter. On the 1st of ^ November,
when the concussions appeared most violent, the water at Gua-
^•dalope retreated twice, and on its return rose in the channel of
die island 10 or 12 feet in height A wave of the sea, 60 fe*t

THE WORLD.

-^^

higft, overflowed a part of the city of Cadiz; and the lake of Ge-
neva was observed to be in commotion six hours after the shock;
agitations were also noticed on lake Ontario. Such is the great
extent of country influenced by these terrible convulsions when
exhibited in their most destructive form, but the changes which
are silently being accomplished, the gradual elevations and sub-
sidences of the land are no less remarkable. Previously to noti-
cing these however, we will allude for a mon^nt to similar phe-
nomena but accomplished suddenly. In the year 1772, during
an eruption of one of the loftiest mountains in the island of Java,
a part of the island, and of the volcano, embracing a tract of
country fifteen miles long, and six miles broad, was swallowed
up, and in 1775, during the eruption which destroyed Lisbon, a
new quay, upon which thousands of the affrighted inhabitants
had congregated, suddenly disappeared, and not one of their bod-
ies ever rose to the surface. In 1692, a tract of land a thousand
acres in extent, in the island of Jamacia, sank down in less than
a minute, and the sea took its ^pce. On the 16th of June 1816,
a violent earthquake happened at Cutch, in Bombay, which so
much altered the eastern channel of the Indus, that from having-
been easily fordable, it was deepened to more than eighteen feet
at low water, and the channel of the river Runn which had some-
times before been almost dry, was no longer fordable except at
one place; and at the same time the mud village and fort of
Sindree, belonging to the Cutch government, and situated where
the Runn joins the Indus, was submerged, leaving only the tops of
the houses above the water. But the subsidence of land caused
by earthquakes is not more remarkable than the elevation, and
many examples might be given of the upraising of land. Perhaps
the most remarkable was during the terrible earthquake in No-
vember 1822, which agitated the western coast of South Ameri-
ca in the vicinity of Chili, for a distance of twelve hundred miles
from north to south. On examining the district around Valpa-
raiso the morning after the shock, it was found that the entire
coast for upwards of«one hundred miles was raised above its for-
mer level, thus leaving dry the bed of the sea. The area of the 0
surface upraised, and which extended from the sea coast to the

TEMPLE OF JUPITER SERAPIS. 261

foot of the Andes, was estimated at one hundred thousand square
miles. The rise upon the coast, was from two to four feet. In
the year 1790 during several shocks, a space of ground three Ital-
ian miles in circumference, sank down near the town of Terra-
nuovo, on the south coast of Sicily. Such are some of the im-
mense changes effected during violent earthquakes. Numerous
examples of immense rents, and sinking down of mountains
might be cited did our limits permit, enough however, has been
adduced, to show that the force which is sometimes generated
far beneath the present surface of the earth, is almost beyond
conception, far exceeding any pressure which human agency can
produce.

The elevation and subsidence of various lines of coast, deter-
mined by water marks, but performed in a very gradual manner
may be appropriately considered in this place. We commence
with the beautiful Bay of Baise, which the researches of Lyell,
Babbage, and other eminent philosophers have rendered a doubly
classic ground. On the golden thores of this beautiful bay, some
pillars and other fragments of an ancient Roman building were
long known to exist. These were once supposed to be the re-
mains of a temple dedicated to Jupiter Serapis, but the researches

of modern antiquaries have rendered it probable that these relics
are the ruijis of an extensive suit of baths. Three of the pillars

262

THE WORLD.

of this supposed temple, are yet standing, and are represented in
the wood cut. These pillars are of marble, carved from a single
block, and forty-two feet in height. One of the columns has a
horizontal fissure extending nearly through it, the others are en-
tire. All are slightly out of the perpendicular, leaning towards
the sea. On these pillars, graven in marks too palpable to be mis-
interpreted, are characters which indicate that twice since the
Christian Era the level of the land and sea has changed at Puz-
zuoli, and each movement, both of subsidence and elevation has
exceeded twenty feet. The surface of these pillars is smooth for
a distance of twelve feet from the pedestal, where a band of perfo-
rations made by a marine boring muscle or bivalve (liihodomus*'),
commences and extends to a height of nine feet, above which,
all traces of their ravages disappear. The holes are pear shaped,
and in many of them shells are still found, notwithstanding the
numbers carried off by curious visitors. The depth and size of
these perforations indicate that the columns must have been sub-
merged for a long time; for the hole, which is at first very small,
and cylindrical, is enlarged by the animal as its size increases
Besides these perforations there are incrustations effected by the
agency of thermal springs in the neighborhood, and at varying
distances, showing the gradual submersion. From all the facts
which have been collected, we may prove pretty conclusively,
as Mr. Babbage has done, that the temple, or rather baths, which
was originally a building of a quadrangular form, seventy feet in
diameter, the roof being supported by twenty-four granite col-
umns, and twenty-two of marble, was built near the sea for con-
venience of the sea-baths, and also for the use of the hot spring
which still exists on the land side of the temple; and that by the
gradual subsidence of the land, a channel was formed, through
which the salt water flowing and mingling with the thermal wa-
ters, a brackish lake was formed, producing an incrustation at
various heights, of from three to four and a half feet, of a differ-
ent character from what either* would produce separately. After
this, the land still subsiding, the channel which admitted the sea

* Lithodomus, from lithos a stone, anu damns a house.

TEMPLE OK JUPITER SERA PIS. 263

became choked by sand, tufa, and ashes, and also the area of the
temple, and thus a lake of the waters of the hot spring was made
the bottom of which would be very irregular, the proofs of this,
are the incrustations of carbonate of lime, presenting a level sur-
face above, but irregular below, and not covering the former in-
crustations. The land still continuing to subside, the sea agaia
encroached, when the lithodomi, attaching themselves to the col-
umns, and fragments of marble, pierced them in all directions,
and this subsidence continued until the pavement of the temple
was nineteen feet below the bottom of the sea. The* base and
lower portions of the temple being protected by the rubbish and
tufa, and the upper, projecting above the water, prevented the
ravages of the lithodomi, on those portions. The platform of the
temple is now about one foot below high water mark, and the sea
is forty yards distant* It is clear therefore, that they have long
been submerged, and again elevated, moving oach time a distance
of twenty-three feet, and yet by so gentle a motion that the col-
umns have not been overthrown. Not far from the temple is the
solfatara or volcanic vent opened in the year 1198, after a series
of earthquakes, and it is highly probable that during these earth-
quakes the land subsided, and the pumice and ashes ejected from
the volcano falling into the sea protected the lower part of
those columns which remained erect, from being bored by the
lithodomi. The re-elevation was probably gradual at first, for we
find in the year 1503, a deed from Ferdinand and Isabella, grant-
ing to the University of Puzzuoli " a portion of land where the sea
is drying up;" but the principal elevation took place in 1538, when
the volcanic cone of Monte Nuovo was formed, at which time,
according to the accounts of eye-witnesses, the sea left the shore
dry for a considerable space. Great as have been the changes of
elevation and depression of the shores of the Bay of Baiae, yet
the movement has been so gentle as not to overthrow these an-
joient remains,

" Whose lonely columns stand sublime
Flinging their shadows from on high
Like dials, which the wizard Time
Had raised to count his ages by."

264 THE WORLD.

At the present moment the land is again subsiding and in th«
same gentle manner.

What was once deemed an encroachment, or rather a rise in
the level of the sea, is now well understood to be but the move-
ment of the coast, gently subsiding, this fact is well illustrated by
the movement of land in Sweden, which is now, and has been
for ages in course of elevation in some places, and depression in
others, rising in the northern, and sinking in the southern parts.
The proof of this great change, which had long been suspected,
was complete upon examining the marks cut upon the rocks by
the officers of the pilotage establishment of Sweden. It was
found that in the space of fourteen years, the rise had been from
four to five inches. The prevalence of marine shells, at some
distance in the interior, of the same species as those now living
in the neighboring seas, renders in highly probable that this rise
has been going on for a long time, in certain portions of that
country. The rocks of the coasts of Norway and Sweden, are
pricipally gneiss, mica-schist, and quartz, and will retain their
particular configuration or appearance unaltered for a long series
of years, there seems therefore, but little room for any doubt as to
the change of level of the land and sea, determined by the an-
cient landmarks, the appearance of new shoals, the elevation of
the lines cut to mark the height of the water years previous, and
the abundant occurrence of marine shells attached to the rocks
at the distance of even fifty miles from the sea coast. From some
phenomena occurring near Stockholm, it would seem that the
land has been depressed and then re-elevated. In the year 1819,
in digging a canal at Sodertelje, a place sixteen miles south of
Stockholm, for the purpose of uniting Lake Maeler with the Bal-
tic, at a depth of sixty feet, the workmen came upon what ap-
peared to have been a buried fishing-hut, constructed of wood, it
was in a state of decomposition, and crumbled away on exposure
to the air. On the floor of the hut, which was in better preserva-
tion, was a fire-place composed of a ring of stones, within which
were found cinders and charred wood, and outside were boughs
of fir, still retaining the leaves and bearing the marks of the axe.
Besides the hut, several vessels of an antique form were found,

ELEVATION «F SKA COASTS. 265

having their timbers fastened together with wooden pegs, instead
of nail.?, indicating their great antiquity. The situation of the
hut seems only to be accounted for on the supposition of a change
similar to that on the shores of the Bay of Baise, first subsiding to
a depth of more than 60 feet, and subsequently being re-elevated.
Examples of this gradual elevation are by no means rare. The
coast of Newfoundland, in the neighborhood of Conception Bay,
and probably the whole island is rising out of the ocean, at a
rate which promises at no very distant period, materially to affect,
if not render useless, many of the best harbors on its coast. At
Port-de-Grave, a series of observations have been made, which
undeniably prove the rapid displacement of the sea-level in the
vicinity. Several large flat rocks, over which schooners might
pass some thirty or forty years ago with the greatest facility, are
now approaching the surface of the water, so that it is scarcely
navigable for a skiff. Dr. Jackson describes a deposit of recent
shells in clay and mud, with the remains of balani or barnacles,
attached to trap rock twenty-six feet above the present high- water
mark, on the margin of Lubec Bay in the State of Maine. •

Changes like these which we have just described, have been
of universal occurrence. Upon this subject Cuvier remarks,
" The lowest and most level lands, when penetrated to a great
depth, exhibit nothing but horizontal strata, consisting of various
substances, almost all of them containing innumerable product-
ions of the sea; similar strata, similar productions, compose the
hills, even to a great height. Sometimes the shells are so nu-
merous that they form, of themselves, the entire mass of the
stratum. They are everywhere so completely preserved, that
even the smallest of them retain their most delicate parts, their
slenderest processes, and their finest points. They are found in
elevations above the level of the ocean, and in places to which
the sea could not now be conveyed by any existing causes. They
are not only enveloped in loose sands, but are incrusted by the.
hardest stones, which they penetrate in all directions." Every
part of the world, the continents, as well as all the islands of any
considerable extent, exhibits the same phenomena; these animals
have, therefore, lived in the sea, and the sea consequently must

266

THE WORLD.

have existed in the places where it has left them. Indeed,', ne
proofs of elevation and subsidence, are everywhere too palpable to
be mistaken. Stratified rocks, or rocks deposited by the agency
of water, form the summits of the highest mountains, elevated
many thousands of feet above the level of the sea. In these
strata, the remains of shells, fishes, and other marine animals are
imbedded. When in addition to this, we observe these strata
not horizontal, but nearly vertical, we cannot resist the conclusion
that they have either been violently upheaved by some tremen-
dous convulsion, or gradually raised by the irresistable agency
of a long continued subterranean force. The evidence of dis-
turbance of the strata, afforded by certain marine worms is im-
portant, and is an instance of the subservience of the actions of
even the meanest of created beings, to the elucidation of truth.
It is well known that certain of these worms, inhabiting straight
and tubular shells, bore the sand in a vertical direction, as repre-
sented in this figure, and if the strata remained undisturbed the

direction of the bore would be always vertical. But the shells
are found in various strata, making various angles with the hori-
zon according to the elevation of the strata, as shown in the K<r-
ure below, and occasionally, a more recent shell will have the

vertical direction as at a, boring the cavity subsequently to the
elevation of the strata. Beds of pebbles, once deposited in reg-
ular horizontal strata, are found making angles with the horizon,
thus witnessing the same fact.

We will now briefly consider some of the most remarkable
earthquakes which have occurred within the historic period. We
commence with the well known one which nearly destroyed the

EARTHQUAKE IN CALABRIA, 1783. 267

city of Messina in 1783. The shocks commenced on the 6th of
February, and ended March 28th, though^ epeated at intervals for
a space of four years. The full and interesting accounts of this
convulsion, carefully prepared by scientific men, render this earth-
quake of much more importance to the geologist than many others
which have occasioned infinitely more destruction of life and
property, but of whose effect in changing the country we are al-
most entirely ignorant. The concussion of this earthquake was
felt over a great part of Sicily, and the \Phole of Calabria, ex-
tending as far as Naples. The centre of the surface which suf-
fered the most, was the small town of Oppido, in the neighbor-
hood of Atramonte, a high, snow-capped peak of the Appenines.
From this point, for a distance of twenty-five miles in all direct-
ions, nearly all the towns and villages were destroyed, and if we
describe a circle with the same centre, having a radius of seventy-
two miles, it will include all the country affected by this earth-
quake. The first shock, February 5th, threw down in the course
of two minutes, the greatest part of the houses in all the cities,
towns, and villages, from the western acclivities of the Appe-
nines, (which traverse Calabria from north to south) in upper
Calabria, to Messina in Sicily, convulsing the whole country.
The granitic chain of mountains was slightly affected by the first
shock, but more sensibly by those" that followed ; the principal
shock being propagated with a wave like motion through the
tertiary sands, sandstones, and clays, from west to east; and where
the line of tertian7 rocks joined the granite, the shocks were most
severe, probably owing to the interruption of the undulatory
movements of the softer strata by the harder granite, which pre-
vented the passage of the shocks to 'the countries on the opposite
sides of the mountain range. About 200 towns and villages were
destroyed, more than one hundred hills slid down, fell together
and damming up rivers, formed lakes. The quay at Messina
sank down fourteen inches below the level of the sea. Deep fis-
sures were caused at several places, and many subsidences, and
upraisings of the ground took place, and the general features of
the country were so altered that they could scarcely be recognized.
Thus in a very short space of time the whole country was as

268 THE WORLD.

much changed as though it had been exposed to common influ-
ences a thousand years^and over 100,000 persons were destroyed.
The movement of the ground was not only horizontal, but vor-
ticose, at some places. This was shown by the partial turning of
the stones of two obelisks at the convent of St. Bruno, in the
small town called Stefano del Bosco, as exhibited in the wood cut
below. The position of the stones was changed nine inches
without their falling.

The most destructive and tremendous earthquake on record, is
that which overthrew Lisbon in 1775. The first shock was on
the morning of November 1st, about half past nine, when, with-
out any other warning than a noise like thunder, heard under-
ground, the foundations of this ill-fated city were violently sha-
ken, and many of the principal edifices fell to the ground in an
instant. Then with scarcely a perceptible pause, the rumbling
noise changed into a quick rattling sound, resembling that of a
wagon driven violently over the stones, this shock threw down
every house, church, convent, and public building; overwhelm-
ing the miserable population with the ruins; it continued about
six minutes. It is said by those who witnessed the effects of this
earthquake, that the bed of the river Tagus appeared dry in
many places, and boats sailing on the river were struck violently

EARTHQUAKE IN PERU, 1746. 269

as though they had run aground. Perhaps the most extraordinary
circumstance which occurred during this earthquake was the sub-
sidence of the new quay called Cats de Prada, built entirely of
marble, and at an immense expense. A great concourse of peo-
ple had fled to this quay, as a spot where they might be safe from
the falling ruins, when suddenly it sank down, with all the peo-
ple on it, and not one of the bodies ever rose to the surface, and a
great number of boats, and small vessels, anchored at the quay
were swallowed up with it, as in a whirlpool, no fragments of
them ever appeared, and the water at the place of the quay has
now a depth of upwards of 100 fathoms. At the time of the
subsidence of the quay, the bar was seen dry from shore to shore,
then suddenly the sea came rolling in, in a wave about fifty feet
high. About noon there was another shock, when the walls of
several houses, which the preceding shocks had not overthrown,
were seen to suddenly gape open, and then to close again so ex-
actly that no fissure or joint could be perceived. The extent of
country affected by this earthquake is almost incredible. The
movement was most violent in Spain, Portugal, and the north of
Africa, but slighter shocks were felt from Greenland and Iceland,
to Norway, Sweden, Germany, Britain, Switzerland, France,
Morocco, Fez, and even in the West Indies; and on Lake Onta-
rio in America. The rate at which the undulatory movement
was propagated was about twenty miles a minute, judging from
the interval of time when the shock was first felt at Lisbon and
the time of its occurrence at other distant places.

In the year 1746, an earthquake occurred which overthrew Li-
ma, in Peru, and inundated its port of Callao, so that only 200
out of 4000 persons escaped. Terrible as were these earthquakes
yet they seem to have been inferior to some which have occurred
at a more early date, in many parts of Asia. Earthquakes are
by no means of uncommon occurrence, scarcely a year passes
without several. They are now observed with great attention by
philosphers, and are of the utmost importance in a geological
point of view. Awful as it must appear to see the ground heav-
ing and swelling like the troubled sea, hills tottering, and solid
walls and towns tumbling into ruins, and the earth gaping open,

270 THE WORLD.

suddenly swallowing thousands of*terrified men, women, and
children, yet the philosopher looks beyond this sight of human
suffering; forgetting the momentary pain and terror, he sees hero
the origin of many of those mighty changes which he had before
detected, and learns many new facts in regard to the former physi*
cal structure and condition of our planet, We have now con-
sidered somewhat at length the aqueous, and igneous, causes of
change in the inorganic world, and we proceed to consider the'
agency of the atmosphere and of vital action.

ATMOSPHERIC CAUSFS OF CHANGE. 271

CHAPTER IX.

^ Atmospheric Causes of Change.

" The seas have changed their beds — the eternal hills
Have stooped with age — the solid continents
Have left their banks — and man's imperial works —
The toil, pride, strength of kingdoms, which had flung
Their haughty honors in the face of heaven,
As if immortal — have been swept away."

Henry Ware.

WE have before described the atmosphere as an elastic fluid
encompassing the earth, and capable of absorbing large quanti-
ties of moisture, and have illustrated the formation of clouds and
the origin of winds. We can easily perceive that so important
an ngent may be capable of effecting the most marked changes,
and we do not now allude to those effects produced by a secon-
dary agency. Thus, the moisture deposited from the air in the
form of rain, or snow, upon loftjir mountains, causes deluges of
water to descend artd overflow the plains below, or becomes the
source of those mighty rivers which roll through thousands of
miles, bearing their immense deposits down to the ocean's bed.
Changes like these we have already considered, and do not there-
fore include them in our present description. The atmosphere
acts as an agent in destroying rocks and changing the face of a
country, mechanically and chemically. The formation of im-
mense dunes, or downs, which are heaps of blown sand, is an
illustration of the former action, and the disintegration and de-
struction of rocks by the absorption of oxygen, and carbonic acid,
is an example of the latter ; both of these actions we will now
briefly consider.

The fine sands of the African desert for a long series of ages,
have been blown by the westerly winds over all the lands capa*
ble of tillage on the western banks of the Nile, involving in the

272 THE WORLD.

«

almost impalpable powder, ancient cities and works of art, ex-
cept at a few places sheltered by the mountains. From the fact
that these moving sands have only reached the fertile plains of
the Nile in modern times, it was inferred by M. de Luc, that that
continent was of recent origin. The same scourge he observes,
would have afflicted Egypt for ages anterior to the time of histo-
ry, had the continents risen above the level of the sea several
hundred centuries before our era. But as Mr. Lyell very justfy
observes, there is no evidence that the whole African continent
was raised at once, and it is possible Egypt and the neighboring
countries might have been populated long before any sands began
to be blown from the western portion, nor is there yet any evi-
dence of the depth of this drift sand, in the various parts of the
great Lybian deserts. Valleys of large dimensions may have
been filled up, and may thus have arrested the progress of the
sand drift for ages. The sand floods which have buried the works
of art on the western countries of the Nile, have contributed
greatly to their preservation. Nothing could be better adapted
than this dry impalpable dust, to protect the features of the col-
lossal sculptures of the temples, or the paintings upon their walls.
Every mark of the chisel remains as perfect as though but yes-
terday from the sculptor's hand| and the colors of the paintings
are as brilliant, as when first laid on, thousands of years ago. At
some remote period, when the causes that now make the air
move in sweeping winds across the Great Desert towards the
Nile shall be removed, when the change of land and sea will
perhaps open that desert to the ocean, after the pyramids shall
have crumbled, towns and temples of higher antiquity, will be
laid open, and a flood of light be shed upon the history of remote
ages. Ere that time, the hieroglyphic writing will be thoroughly
understood, and the years of the Egyptian dynasties as well de-
termined as the reigns of modern kings. The great agent of de-
composition in other places, moisture, is unknown there. The
spectator who looks for the first time upon the immense cavern
temple at Ipsambul in Nubia, might well imagine that the artists
had just left their work. The walls are as white, the colors as
perfect, and the outlines as sharp, as in the first hour of their ex-

istence, and when he surveys the tracings, and half-finished
sculpture he might almost look for the return of the artists to
complete their work. Such is the wonderful preservation of
these works in the fine blown sand of the great deserts, that al*-
though the buildings have been roofless for two thousand years,
the paintings are undefaced. " There are some small chambers
in a temple at Abydos" says Sir* F. Hennicker, " in which the
color of the painting is so well preserved that doubts immediate-
ly arise as to the length of time that it has been done. The best
works even of the Venetian school, betray their age; but the col-
ors here, which we are told were in existence two thousand years
before the time of Titian, are at this moment as fresh as if
they had not been laid on an hour." The preservation of works
usually esteemed as fugitive, being so perfect, we might expect
that those executed in more durable materials the sienite, granite,
basalt, and limestone, would be still more so, and we find frag-
ments of temples leveled to the ground by Cambyses, five hun-
dred years before the Christian Era still retaining their pristine
polish. The north and east faces of the obelisk, still erect among
the ruins of Alexandria, retain much of their original sharpness,
but the south and west sides have been entirely defaced by the
attrition of the minute particles, of sand with which the air is
charged, beating against them sixteen hundred years. The des-
olation brought upon those ancient cities by the irresistable en-
croachments of the desert, the remains of its immense temples
and works of art, its silent chambers, where the wrapped-up dead
hav^j remained for two hundred centuries, who once trode the
streets of ancient Thebes, with all the buoyancy of feeling and
all the hope which animates men now, furnishes a striking in-
stance of the influence of apparently insignificant causes,, in pro-
ducing the greatest results, and remind us of the prophet's decla-
ration, " Wo to the land shadowing with wings." But the an-
cient cities of Nubia, and Upper Egypt, are not the only places
buried in blown sand, there are numerous instances of towns
and villages, in England and France, thus overwhelmed. For
example, near St. Pol de Leon, in Brittany, a whole village was
tompletely buried beneath drift sand, so that nothing but the

S?4 THE WORLD,

X

spire of the church could be seen. In the course of a century it
is said that a thousand acres of land in Suffolk were covered by
blown sand; and a considerable tract of land on the north coast of
Cornwall has been thus inundated, and ancient buildings are of-
ten brought to light by its shifting; and in some cases, in boring
for water, distinct strata of the sand separated by a vegetable
crust are found. The name o£ dunes, or downs, has been given
to these moving sand hills, which are first generated on the sea
shore. The sea-breeze drives the fine sand, farther and farther
inward, until it accumulates and becomes a formidable hill.
There are many instances of these hills in the United States,
particularly in the south eastern part of Massachusetts, and near
Cape Cod, where they are sixty or seventy feet high, and of al-
most snowy whiteness. Here these dunes are moving gradually
westward, the strength of the land-breeze not being sufficient to
counteract the effect of the sea-breeze. A series of these dunes
now threaten the village and Bay of Provincetown, and large
quantities of beach-grass have been transplanted to their ridges
for the purpose of arresting their progress.

The chemical agency of the atmosphere is another important
means of change producing a sure and often rapid decay of the
solid materials of our globe. The forces of chemical affinity are
superior to those of cohesion 'and aggregation, and the atmos-
phere charged with moisture and carbonic acid gas, disintegrates
the solid materials, which crumble away before this "gnawing
tooth of time." The resistance which rocks afford to decom-
position depends greatly upon their composition, but all are more
or less affected. A very slight examination of the soil in any
rocky country will suffice (o show that it has been derived from
the decomposition of the rocks in the vicinity. In granitic coun-
tries we find the soil made up of shining particles of silex or
quartz, and spangles of mica, and particles of felspar, and even
the finest portions will be found thus composed. Sienite and
hornblend rock, when decomposed, yield a darker soil, containing
much more felspar and less quartz, while slaty rocks give a dark
colored tint to the soil, forming beds of tough blue clay, when
deposited by water. We have already alluded to the consolida-

CHEMICAL INFLUENCE OF THE ATMOSPHERE; 275

tion of loose materials by the infiltration of calcareous matter, or
by iron ; the destruction of such aggregations is no less remark*
able. Thus we find rocks which contain iron pyrites or sulpur-
et of iron, constantly crumbling to pieces^ The oxygen of the
atmosphere, and of the watery vapor with which it is charged.,
combining with the sulphur, forms sulphate of iron or copperas,
the sulphuric acid of which, acts powerfully on the rock. Rocks
which contain potash and soda are also very liable to disintegra-
tion. Indeed, it is not a little remarkable that our supplies of
these valuable alkalies, particularly of the potash, are obtained
from the vegetable kingdom, salts of potash containing some
vegetable acid are of constant occurrence in plants, performing a
hidden but yet important part in their economy ; when these
plants are burned, the organic acids are destroyed* and the potash
remains in the state of carbonate, or united with carbonic acid.
The great natural depository of potash is the felspar of the gran-
itic and other unstratified rocks, combined with silica in an in-
soluble state. When these rocks disintegrate into soil, the alkali
acquires solubility. Rocks which readily absorb moisture are
liable to decay ; the red sandstone, or freestone, for example,
which ie destroyed very rapidly according to its porosity, by the
splitting of portions of the stone in consequence of the freezing
of the water. De la Beche, observes that, " rocks receive con-
siderable chemical modification by the percolation of water
through them. There is scarcely any spring-water, which does
not contain some mineral substances in solution, which it must
have procured in its passage through the rocks. Now, though
this'quantity may be small, when we regard the composition of
any particular spring-water, yet, when we consider the soluble
matter contained in the spring-waters of any given 1000 square
miles of country, and that this subtraction of matter from rocks
has been going on for ages, we may readily conceive that the
chemical change, may be greater than, at first sight we might
anticipate. We may also infer that the most soluble portions of
rock, have a constant tendency to be removed, when exposed not
only to direct atmospheric influences, but also to the percolation
of rain-water through them, so that most rocks would experience

276 fttK vvonr.h.

great difficulty in resisting chemical changes of this kind, and of
preserving their original chemical nature, more particularly when
elevated into the atmosphere." We have already had occasion
to remark upon the large amount of calcareous and silicious mat-
ters held in solution by water, which matter has been often de-
rived from the percolation of that fluid through limestone districts,
or rocks containing felspar^ for it is well known that in the de-
composition of such rocks, producing the porcelain clay, an
enomous quantity of silex is carried off in solution. In the re-
gion of extinct volcanoes in France, the district of Auverg»e,
the destruction of granite is very rapid, owing to the liberation
of large quantities of carbonic acid. "The disintegration of
granite," says Lye 11, "is a striking feature of large districts in
Auvergne. This decay was called by Dolomieu 'la maladie du
granite,' and the rock may, with propriety, be said to have the
rot, for it crumbles to pieces in the hand. The phenomenon may,
without doubt, be ascribed to the continual disengagement of
carbonic acid gas from numerous fissures. In the Plains of the
Po, I observed great beds of alluvium, consisting of primary peb-
bles, percolated by spring water, charged with carbonate of lime
and carbonic acid in great abundance. They are, for the most
part, incrusted with calc sinter ; and the rounded blocks of gneiss,
which have all the outward appearance of solidity, have been so
disintegrated by the carbonic acid as readily to fall to pieces."

We can now perceive how little of stability or permanancy is
inscribed upon the face of nature. The gilded insect which flut-
ters its short hour over the flowers of a day, deems its life and
happiness lasting, and what better are our own thoughts; we look
upon the earth as unchangeable, when, for ought we know, the
next instant may behold all our possessions swallowed up, or blown
into the air. We carve to ourselves costly monuments, perpetua-
ting the deeds of martial bravery, or the fame of a patriot, we
protect them from the hands of the rude by various means, but
a more formidable enemy, because less known, and dreaded, is
passing by, and silently effecting the work of desolation. Change,
perpetual change, is inscribed by the finger of the Almighty up-
on the face of everything. No art can arrest the insidious at-

DESTRUCTION or ROCKS. 2?7

lacks which thus cause the richest works of man to crumble si-
lently away.

•• It is painful," says Philips, "to mark the injuries effected by
a few centuries on the richly sculptured arches of the Romans,
the graceful mouldings of the early English architects, and the
rich foliage of the decorated and later Gothic styles. The chang-
ing temperature and moisture of the air communicated to tho
slowly conducting stone, especially on the western and southern
fronts of buildings, bursts the parts near the surface into powder,
'or, by introducing a new arrangement of the particles, separates
the external from the internal parts, and causes the exfoliation or
desquamation, as Mac Culloch calls it, of whole sheets of stone
parallel to the ornamental work of the mason. From these at-
tacks no shelter can wholly protect; the parts of a building which
are below a ledge often decay the first; oiling and painting will
only retard the destruction; and stones which resist all watery
agency, and refuse to burst with changes of temperature, are
secretlv eaten away by the chemical forces of carbonic acid and
other atmospheric influences. What is thought to be more dura-
ble than granite ? Yet this rock is rapidly consumed by the
decomposition of its felspar, effected by carbonic acid gas; a pro-
cess which is sometimes conspicuous even in Britain, but is usu-
ally performed in Auvergne, where carbonic acid gas issues plen-
tifully from the volcanic regions."

The most durable rocks appear to be the limestones of the
Silurian formation, but some of the sandstones of the more re-
cent formations are exceedingly perishable. This may be seen
upon examining the tombstones of red sandstone, which were
formerly used very extensively in New England, their inscriptions
will generally be found illegible. The durability of sandstones
depends much upon the nature of the cement which binds the
particles together, if this be calcareous they are not so durable as
if silicious, and if the stones contain iron, they are generally
highly perishable. Such stones which, may always be detected
from their iron -brown, or rusty appearance, should be rejected
for building stone.
M

878 TH

Such are some of the effects of causes continually, and yet
silently operating around us. It is true that many years are re-
quired to produce changes of great importance, and the opera-
tion is so gradual that the wonder ceases, almost ere it begins.
In investigations however, so comprehensive as those we have
been considering, a day, a year, or a hundred years, is but as the
grain of sand to a mountain. It is indeed very true that the pres-
ent generation may pass away, and yet think they leave all things
as they were of old, looking with a listless apathy upon the face of
nature. The true philosopher improves the fleeing moment, and
enlarges his affections, and expands his imagination by the con-
templation of loftier subjects, and so fits himself to depart froiri
this changing scene, with the consolation of not having lived iii
vain.

VITAL CAUSES OF CHANGE. 2?U

CHAPTER X,

Coral Animalcules.

"Deep in the wave is a coral grove,

Where the purple mullet and gold-fish rove»
Where the sea-flower spreads its leaves of blue»
That never are wet with falling dew,
But in bright and changeful beauty shine,
Far down in the green and glassy brine."

PercivaL

WE now enter upon a most interesting branch of our subject,
the influence of organic action in producing change, and we will
soon find that of all agents which at the present moment are form"
ing rocks, the most remarkable are those minute and fragile ani-
mals termed Coral Animalcules. A vast number of islands in
the Pacific, Indian, and Atlantic oceans are entirely composed of
the calcareous skeletons of these minute animals, and they are at
the present moment rapidly increasing in their extent. Straits
and seas, once easily and safely navigable, are now rendered ex-
tremely dangerous, and even impassable. It will not be unpro-
fitable or uninteresting to devote a short space to the considera-
tion of these wonderful specimens of organic existence.

The nature of coral animalcules is but little understood by most
persons, they suppose that the hard calcareous substance called
coral, is a part of the animal itself, this, however, is not the case.
The stony substance, may be compared to an internal skeleton,
for it is surrounded by a soft animal investment, capable of ex-
panding, and when alarmed, of contracting and drawing itself
almost wholly into the hollows of the hard coral. Though often
beautifully colored in their own element, yet when taken out of
the water they appear like a brown slime spread over the stony
nucleus. The coral animalcule*, exist in a great variety of forme

280 tHE WORLDt

and of various sizes, some of them are so minute that they cannot
be seen without a microscope. They are congregated together
like other zoophytes, each individual being connected to a com-
mon body, so that what is received by any one goes to the nour-
ishment of the whole. The stony matter, or hard substance of
the zoophyte, is formed as are the bones and nails in man, by se-
cretions from the animal substance, by which they are penetrated
and invested, The cells of the coral, therefore are not built up
by the polypi, as they are called, in the same manner as the wax-
en cells of the bee. We may often observe little patches of
yellowish calcareous matter on sea-weed, or shells thrown upon
the shore, this upon examination appears to be a kind of delicate
net-work, but when examined with a microscope the substance is
found to be full of pores, and if the examination is made while
i\\e,fiustra or calcareous matter is immersed in the water, each
pore will appear to be the opening of a cell, whence issues a tube
with several long arms or feelers; sometimes these expand, and
then suddenly close and are withdrawn into the cells, then issue
forth again. Thus each individual of the group occupies its own
particular cell, but the whole constitutes one family of polypes
connected by a common integument, or fleshy or gelatinous sub-
stance which invests the whole. Figure 1, of the wood-cut be-
low exhibits the series of cells of the fiustra, systematically

arranged. Each cavity is the receptacle of a polype shown with
the tenlacula, or feelers, expanded in fig. 2, and contracted into
its cell in fig. 3. These views are from drawings made by Mr.
Lister, and figured by Dr. Mantell, in his excellent •» Wonders of
Geology." The animals just described are members «jf the same

BRAIN-STONK CORAL. 1

family by whose secretions vast reefs of coral rocks are formed,
and mountain masses of calcareous matter produced. They be-
long to the order Coraliferi, or coral-making, and the class
Polypi of Cuvier's Animal Kingdom. The mode of increase of
the polyparia is very remarkable. If the flustra just referred to,
be carefully watched, a small globule will be observed to be thrown
off from the mass, and attaching itself to the sea-weed or rocks,
will become the germ of a new colony of this compound animal,
as it increases in size it will exhibit upon closer inspection the
usual characteristics of the flustra, and if the gelatinous or jelly-
like substance is removed, a small spot of calcareous matter will
be found. The stony secretions of the coral forming animals,
appears upon examination to be of the same character as that of
shells; some specimens appearing of the same composition as
the pearly shells, and others the same as the enamelled shells. In
form and color there is condiderable diversity. Our limits will
only permit us to give figures of several of the different species,
without a lengthened or minute description. The most common
varieties of corals, which compose the coral reefs and banks, are
the following, according to Lamarck. The Meandrina, or brain-
stone coral, which derives its name from the meandering cells,
and its general appearance, which resembles the brain, as figured
below. Figure 1, represents the animal as seen alive in the sea,

the polypi are retracted or concealed, it is of a reddish or fawn
color. Fig. 2 is the coral as it appears when divested of its gelatin-
ous covering. This zoophyte sometimes attains the size of four
feet in circumference. The base of the Meandrina is firmly at-
tached to the rocks with which it soon becomes identical : as each

y»2 THE WORLD.

successive fleshy mass expires, a new one appears, which gradu-
ally expands and deposits its calcareous secretions upon the old
one, and thus vast beds of stony matter are accumulated in the
bottom of the sea, and become the foundations of coral reefs and
islands. " We may compare" observes Mr. Lyell, " the opera-
tion of these zoophytes in the ocean to the effects produced on a
smaller scale upon the land by the plants which generate peat.
In the case of the Spagnum, (page 204), the upper part vege-
tates while the lower portion is entering into a mineral mass, in
which the traces of organization remain, when life has entirely
ceased. In corals, in like manner, the more durable mate-
rials of the generation that has passed away, serve as the founda-
tion on which living animals are continuing to rear a similar
structure." The Caryophilla, or branched star-like coral, is an-
other common species. We give an engraving of an American
specimen as it appears when alive. The three branches, each

contain a bright green polypus. The Astrea, is another very
common and extensive species of coral, fig. 1, represents the

coral as seen alive in the sea. the polypi are of a dark green

283

color, and about half an inch in length, protected by deep lami-
nated polygonal cells one-sixth of an inch wide; fig. 3, represents
the coral with the animal removed, its name astrea or star-like,
is derived from its radiated or starry appearance. Fig. 2, is a
magnified view of one of the polypes. The tentaculae, or arms,
are seen arranged around the mouth. The appearance of these
animals alive, and in activity, is most beautiful when viewed in
tranquil water. The surface of the rock appears like a living
mass, presenting a great diversity of appearance and color. The
Madrepore, or branched cellular coral, is well known, being per-
haps the most common species. It will be immediately recog-
nized upon inspecting the figure we have given below.. In some

species after the fleshy investment perishes, the little cells appear
very numerous as in the figure. The white branched corals usu-
ally seen in collections belong to this genus. In the water, the
Madrepores are invested with fleshy integuments of vario.us colors
and each cell is furnished with its own polype. We have now
enumerated the several species of zoophytes most active in the
formations of reefs. The stony secretions of all these, when
bleached by the action of moisture and light, are of a dazzling
whiteness. There is however, a species of coral, Corattium ru-
krum, or red coral, the stony secretion of which is a bright red
color, very beautiful and susceptible of a high polish. A speci-
men of this coral is here figured. It consists of a brilliant red
stony axis invested with a fleshy or gelatinous substance of a pale

284 THE WORtTA

blue color, attached to the rocks by a broad expansion of its base.

In the figure, the fleshy substance is removed at the extremities
to exhibit the stony axis. It is seldom found more than a foot in
length, and is well known, being used for various ornamental
purposes, and is obtained by dredging in various parts of the-
Mediterranean and Eastern seas. Another species of red coral;

the organ-pipe, or tnbipora, is shown in the abore wood-cut,,
this derives its name from its tubular appearance, being com-
posed of parallel tubes united by lateral plates or transverse
partitions placed at regular distances. The polypi of this coral are
of a beautiful green color. This species occurs on the coast of
New South Wales, and in the islands of the Molucca group, in
hemispherical masses of from one to two feet in circumference,
which first appear as small specks, adhering to the rock, these
gradually increase, and the tubes shoot forth like little rays; other
tubes spring from the transverse plates, finally constituting a uni-
form tubular mass, the surface being covered with a green fleshy
substance, beset with stellar animalcules.

The geographical distribution of corals is very extended. The
Pacific, throughout a space comprehended between the 30th
parallel of latitude, on each side of the equator is very productive-,
and also the Persian and Arabian Gidfs. They are very abundant

APPEARANCE OF LIVING CORALS. 285

in the Indian ocean and some parts of the Atlantic. Many spe-
cies of this genus are found along our Atlantic coast and on the
shores of England. Some species seem to prefer the more ex-
posed situations, flourishing in the greatest profusion, on rocks
and plants which the tide every day leaves bare ; the larger
polyparia however, are seldom found in places exposed to violent
currents; they flourish in the submarine grottoes and hollows of
the rock, where they shoot out their delicately branching forms
studded with zoophytes of most brilliant colors. Others attach
themselves to the flexible branches of the sea plants, encasing
them in a living tomb, and are thus fitted to enjoy the powerful
action of the surges; the pliant branches bending to and fro, with
the movements of the waters. Others form immoveable rocks,
and slowly increase, until at last an island is elevated above the
waters. The distribution of corals, like that of plants, varies with
the climate. In the colder northern latitudes, a few sponges, and
sertulariffi alone are found, but in the warmer, equatorial regions,
within the tropics, they attain a luxuriance and beauty, a gran-
deur and importance well worthy our attention. Here, in an
ocean of uniform temperature, they elevate those immense reefs
which eventually become the habitations of men, and even gar-
dens producing rich tropical fruits and flowers. These minute
beings, myriads upon myriads, here exercise their empire, some-
times, in the sheltered places, or still lagoons, shooting forth the
most delicate branches, and in others, whe:-e the surges beat upon
them, growing firm and solid as the rock on which they are based.
The appearance of the living corals in the water is described as
most enchanting. The whole bed of the Rrd Sea is absolutely
a forest of sea-plants and corals, presenting the appearance of a
submarine garden of the most exquisite verdure, resembling in
splendor and gorgeous coloring the most celebrated parterres of
the East. Ehrenberg, the distinguished German naturalist, so
well known by his admirable investigations of infusoriee, was so
struck with the view of the living corals in the Red Sea, that he
exclaimed with enthusiasm " Where is the paradise of flowers
that can rival in beauty these living wonders of the ocean ?" Some

286

THE WORLD.

have compared their appearance to beds of tulips or dahlias; and,
in truth, the large fungiae, with their crimson disks, and purple
and yellow tentacula, bear no slight resemblance to the latter.

The tender branches of the corals furnish food to some species
of fish, which graze upon them in whole shoals, both within the
lagoons in the quiet waters, and among the breakers on the out-
side of the reef. Nothing can be imagined more beautiful than
the scene presented in the tropical climates, especially where the
shore consists of alternate beds of sand, and masses of rock.
" Groves of coral are seen expanding their variously colored
clumps, some rigid and immovable, and others waving grace-
fully their flexile branches ; shells of every form and hue, glide
slowly among the stones, or cling to the coral boughs like fruit ;
crabs and other marine animals, pursue their prey in the cran-
nies of the rock, and sea-plants spread their limber fronds, in
gay and guady irregularity, while the most beautiful fishes are on
every side sporting around."

VITAL CAIJSKS OF CHANGE, 287

CHAPTER XI.

Coral Islands.

'*! saw the living pile ascend,
The mausoleum of its architects,
Still dying upwards as their labors closed;
Slime the materials, but the slime was turned
To adamant by their petrific touch."

J. Montgomery.

HAVING in the preceding chapter given a brief description of
some of the more common varieties of corals, we shall now con-
sider more fully the agency of these wonderful animals in the
formation of rocks. It has been generally considered that the
zoophytes cannot live in water of very great depths, and that
therefore their structures are based upon submarine mountains.
This view has been confirmed by the observations of Ehrenberg,
and more recently by the careful soundings of Captain Fitz Roy,
of the Royal English Navy. At a depth of ten fathoms the pre-
pared tallow invariably came up marked with the impressions of
the living corals, and as clean as if it had been dropped on a car-
pet of turf; at a greater depth the impressions were less numer-
ous, and the adhering particles of sand much more frequent,
until at a mean depth of twenty-five fathoms it was evident that
the bottom consisted of a smooth sandy layer. We may conclude
therefore that the reef building corals, do not usually flourish
much below this depth. The formation of the coral islets is
somewhat analagous to the growth of a tree which has been
headed. The zoophyte cannot endure even a short exposure to
the sun's rays in the air, their growth npw ards is therefore checked
as soon as the surface of the water is reached. They spread out
laterally however, not unlike the top of a tree.

The appearance and formation of coral islands has been de-
scribed vnry minutely by a great mimb<>r of distinguished natural-

288 TH

ists, and various theories have been proposed to explain the ob-
served phenomena. We have devoted some little attention to-
this part of our subject, and are best satisfied with the explanation
given by Mr. Chas. Darwin, in a paper read before the Geologi-
cal Society in May 1837V and which we will explain presently.
Everywhere, in the Pacific and Indian Oceans, within tha tropics,
may be seen coral banks in their various stages of progress ; some
covered with light soil, and the habitations of man. Most of the
reefs which raise themselves above the waters are of a circular
form, enclosing a basin of still water, called a lagoon r which
connects by means of one o-r two channels with the sea. In the
interior of the island, the more delicate and smaller kinds of
zoophytes live, while the stronger and hardier species, fitted to?
endure the beating of the surf, flourish on the outer margin of
the isle. When the reef rises so high that it is left uncovered at
low water, the corals cease to increase, the animals die, and the
branches become somewhat decomposed. Fragments of coral
limestone are thrown up by Ihe waves, with shells, and broken
fragments of crustacean animals, seeds are floated by the waves
towards the new formed island, and thrown upon its shores ; and
trunks of trees, drifted thousands of miles, find a lodgment upon
it, bringing with them small animals, as insects and lizards.
Bushes and trees, spring up, and the sea-birds nestle there, and
finally at a later period, it becomes the habitation of man. The
reefs of coral, consist not only of the corals, and their broke»
fragments, but masses of com] act limestone, and imbedded shells
are of frequent occurrence. The limestone is found sometimes
in the uppermost or newest parts of the reef, and is formed by
chemical decomposition, the carbonate of lime being supplied
from the decomposition of corals and testacea.

We have already alluded to the geographical distribution of
corals, we may however, form some idea of the immense extent
of the coral reefs when we learn that, off the coast of Malabar,
in the Indian Ocean, there is a chain of coral islands of over 480
miles in length, called the Maldiva Group. On the coast of New
Holland, is an unbroken reef 350 miles in length, and between
that and the island of New Guinea is a coral formation which

AfOLLS. 289

extends upwards of 700 miles ; and Disappointment Island and
Duff's Group, are connected by a coral reef of 600 miles length,
over which the natives pass from one island to another.

Coral reefs are divided into three great classes, namely Atolls,
Barrier, and Fringing reefs. The word atoll is the name given
by the natives to the circular islands enclosing a lagoon, or still
water in the centre. This is the most usual form of the coral
islands, and fails not to strike the attention of every one who has
crossed the Pacific. They occur of all s'izes ; of thirty-two ex-
amined by Capt. Beechy, the largest was thirty miles in diameter,
and the smallest less than a mile, they were of various shapes
and all but one, formed by living corals. This one had been
raised from the water about eighty feet, but was of coral forma-
tifen, and was encircled by a reef of living corals. All were slowly
increasing their size, and twenty-nine of them had lagoons in the
centre, which had probably existed in the others, until, in the
course of time, they were filled by the labors of the zoophytes,
and other substances. It was supposed by the earlier voyagers
that the coral-building animals instinctively built in the form of
great circles to protect themselves from the fury of the waters.
So far however, from this being the case, we have seen that those
massive kinds upon whose existence and increase, the reef de-
pends, flourish beat among the breakers on the outside of the
reef. Another and more probable theory, is that advocated by
Mr. Lyell, that they are based upon the crests of submarine cra-
ters, and this idea receives confirmation from the steep angle at
which the island plunges at all sides into the surrounding ocean,
and that every island yet examined in the immense region called
Eastern Oceanica, consists of volcanic rocks, or coral limestones.
In opposition to this opinion it is very plausibly argued by Mr.
Darwin, that the form and size of some, and the number, prox-
imity, and relative positions of others, are incompatible with this
theory. Thus, Suadiva atoll is 44 geographical miles in diame-
ter in one direction, and 34 in another; Rumsky atoll is 54 by 20
miles across; Bow atoll is 30 miles long, but only six in width.
Another theory, proposed by Chamisso, accounts for the circular
form of coral islands upon the well known fact, that the corals

290

THE WORLD.

growing more vigorously around the outside where exposed to the
sea, the outer edges would grow up from the foundation before
any other part; thus making a ring or cup-shaped structure; but
we are not by this -theory relieved from the difficulty of answer-
ing the question, upon what are these massive structures based ?
since it is well known that the reef-building corals cannot live at
any very considerable depth, though indeed, other species have
been found at a depth of GO fathoms. Below we give a view of
one of these islands, copied from Capt. Beechy. The circular
form is well exhibited in this island, which is called Whitsunday,
but it gives a faint idea of the singular appearance of an atoll,

being one of the smallest size. The immensity of the ocean, the
fury of the breakers, contrasted with the lowness of the land,
and the smothness of the bright green water within the lagoon
can hardly be imagined without having been seen.

The second great class of reefs are the Barrier-reefs, these are
similar in all respects to the atolls except having a high land like
a castle rising out of the lagoon. The following sketch from Mr.
Darwin, will give an idea of the appearance of one of these
wonderful structures, being a part of the island of Bolabola in
the Pacific, as seen from one of the central peaks. In this in-
stance the whole line of reef has been converted into land, upon
which trees are growing; but generally, a snow-white line of
breakers, with onlv here nnd there n lowislpt covered with roooa-

BARRIER REEFS.

291

nut trees, can be seen separating the dark heaving waters of the
ocean from the light green expanse of the lagoon, the still waters

of which, within the reef, usually hatlie a fringe of low alluvial
soil, upon which the varied and beautiful productions of the tropi-
cal regions flourish at the foot of the abrupt and wild central
peaks. In the sketch given above, the barrier-reef may be seen
in the distance skirting around the island. These reefs are of all
sizes from three to forty miles in diameter; and the one which
encircles both ends and fronts one side of New Caledonia is up-
wards of 400 miles long. Externally the reef ris^s like an atoll
with abruptness out of the profound depth of the ocean, but in-
ternally it either slopes gradually into the channel, or terminates
in a perpendicular wall 200 or 300 feet in height.

There is one remarkable feature connected with the circular
reefs, and that is, a deep and narrow passage almost invariably
opening from the sea into the lagoon, and kept open by the efflux
of the sea at low tides, and it has long been remarked in the
case of the barrier reefs, that this channel or opening alway
faced valleys in the included land.

The third great class are the Fringing reefs, these, so far as the
coral reef itself is concerned, do not differ materially from the
others, except that the encircling belt of coral is much narrower.
Where the land slopes abruptly into the water the reefs are but a
few yards in width, forming a mere ribband or fringe around the
island, but when the slope is gradual, the width is much increased

292 THE

extending sometimes as far as a mile from the land, and always
to such a distance from the shore that the limiting depth of 20 or
30 fathoms is obtained, where the reef ceases. From the more
flourishing growth of the outermost corals, the fringing reefs are
usually highest at the outside, and the sediment washed inwards
upon the reef, generally produces in the course of time, a shallow
sandy channel* Such are the three great classes of coral reefs
which are found scattered throughout the vast oceans, and princi-
pally in the tropical regions, but it must by no means be supposed
that they are found indiscriminately united, on the contrary the
atolls and barrier-reefs are never found in proximity to the fring-
ing reefs. It has been remarked with surprise that while atolls
are the most cojnmon coral structures throughout some vast por-
tions of the ocean, such as the tropical Pacific and the Indian
Oceans, they are entirely wanting, or very nearly so, in the tropi-
cal Atlantic and West Indian Seas, where the corals themselves,
are exceedingly numerous. There is also another somewhat re-
markable fact, that no single active volcano occurs within several
hundred miles of a coral archipelago, or even a small group of
atolls ; and although most of the islands in the Pacific which are
encircled by barrier-reefs are of volcanic origin, having remains
of craters distinctly visible, yet not one of them is known to have
been in eruption since the growth of the corals. In explaining
by any theory the formation of coral reefs, we must consider all
the phenomena presented by the three great classes as enumera-
ted in the preceding description. To ourselves the explanation
proposed by Mr. Darwin in his volume upon *« The structure and
distribution of Coral Reefs," is the most satisfactory, and maybe
briefly stated thus; islands, or a line of coast, being first skirted
with fringing reefs, become atolls by a continual but gradual subsi-

LEVEL Or SE
dence of the land. Let us then take an island surrounded by

BARRIER REEKS, 293

fringing reefs, and let this island with its reef, represented by the
unbroken lines in the wood cut, slowlv subside. As the island sinks
down, the reel continually grows upward; as the island subsides
the space between the inner edge of the reef and the beach be-
comes proportionally broader. A section of the reef and island
in this state is represented by the dotted lines, A A, being the
outer edges of the reef; C C, the lagoon; B B, the shores of the
encircled island. This section is a real one (on the scale of .388
of an inch to the mile), through Bolabola in the Pacific. We
can now see why the barrier reefs are so far from the shores which
they front. Supposing the island to still subside, the corals mean-
time growing vigorously upward, the last traces of land will finally
disappear, and a perfect atoll be formed. We thus perceive why
atolls so much resemble the harrier reefs in general size, form,
and manner in which they are grouped together, for they are but
the rude outlines of the sunken islands over which they stand.
In proof of the foregoing simple and not at all improbable cause
for the formation of barrier reefs, and atolls, Mr. Darwin gives
some examples of actual subsidence now in progress, and also
presents some evidence of the recent elevation of those islands
and coasts which have fringing reefs. The sinking of the islands,
or coast, for the formation of barrier reefs, or atolls, must neces-
sarily have been very slow, and undoubtedly large archipelagos
and lofty islands once existed, where now only rings of coral rock
scarce break the open expanse of the sea; thus the only record
left to us of the existence of vast tracts of land are the wonderful
memorials of these busy architects ; in each barrier reef we see
evidence of land subsided, and in each atoll a monument of an
island lost. Busy from the first ages of the world, when the
primeval seas had but a few groups of living beings, of the low-
est order of organization, the coral polype has toiled from day to
day, and year to year, and is toiling now. What mighty changes
have p;tssed over our giobe since that remote period in which the
Geologist is first enabled to trace the existence of living beings
upon the earth. How many tens of thousands of times the earth
has revolved around the sun, and how many hugo mountain
chains of granite have been disintegrated, and their scattered frag-

TUK WORLD.

ments deposited in the deep bed of the ocean. Perhaps the
foundation of some of our present coral islands, was begun in
those remote ages, and that the successive architects of the solid
pile, have reared a structure which has witnessed more than
one revolution of the major axis of the earth's orbit.

We close with the following beautiful description of a cora*
grove, by Percival.

" The floor is of sand, like the mountain-drift,

And the pearl-shells spangle the flinty snow ;
From coral rocks the sea-plants lift

Their boughs, where the tides and billows flow ;
The water is calm and still below,

For the winds and the waves are absent there ;
And the sands are bright as the stars that glow

In the motionless fields of the upper air.
There with its waving blade of green,

The sea-flag streams through the silent water,
And the crimson leaf of the dulse is seen

To blush like a banner bathed in slaughter ;
There with a light and easy motion

The fan-coral sweeps through the clear deep sea ; *•
And the yellow and scarlet tufts of ocean

Are bending like corn on the upland lea ;
And life in rare and beautiful forms

Is sporting amid those bowers of stone,
And is safe when the wrathful spirit of storms

Has made the top of the waves his own.
And when the ship from his fury flies

Wher,e the myriad voices of ocean roar,
When the wind-god frowns in the murky skies,

And demons are waiting the wreck on shore,
Then far below in the peaceful sea

The purple mullet and gold-fish rove,
Where the waters murmur tranquilly

Through the bending twigs of the coral -grove."

ORGANIC R01AINS. 295

CHAPTER XII.

^Organic Remains.

<*

"And thou didst shine, thou rolling moon, upon
All this, and cast a wide and tender light,
Which softened down the hoar austerity
Of rugged desolation, and fill'd up,
As 'twere, anew, the gaps of centuries."

Byron.

IN the preceding chapters we have, though somewhat imper-
fectly, given a sketch of the great causes of change now in ope-
ration on our globe, and we have shown that the earth's surface
has been, and still is, subject to perpetual mutations. What was
once dry land is now the bed of the ocean, and what is now
the bed of the sea will one day be elevated land. We have also
seen that the crust or superficial covering of the globe is com-
posed of strata succeeding each other in a well determined and
regular order, and the remains of countless myriads of animals
are entombed in them, which lived and died at periods long ante-
cedent to the creation of the human race, nay, more than this,
that almost every grain of sand and particle of dust wafted by the
wind, teems with organized matter. We have lying before us
specimens of whitish earth which to the unassisted eye appears
but light chalky powder ; w© have but to wet a little of it and place
it under the microscope and a thousand perfect forms are visi-
ble. From the midst of a lump of chalk we have extracted a
nodule of flint, and by the hammer have chipped off several thin
slices ; one of these is now under the microscope by us, and we
distinctly recognize two beautiful species of infusoria, as perfect
and well defined as though now alive, and yet, these little beings
have been entombed for myriads of years. What mighty changes
have come over the face of our globe since the flinty sea encom-

296 THE WORLD.

passed them, and how few of the countless thousands of all that
sea, have been preserved for the curious gaze of the student of
nature. The thoughts which overwhelm the mind when con-
templating the wonders of the universe, impress us with almost
a feeling of sadness that creation is so vast we can never compre-
hend the whole of it. The influence however, of scientific pur-
suits upon the mind, is most beneficial, and the great lesson
taught by science is, that our habitual ideas, and our first im-
pressions are far from being nearest the truth. Indeed we have
already observed in the first part of this work, that Astronomy
begins by convincing us that the sun, which apparently is revolv-
ing around the eaith, is in reality still, but that our globe is turn-
ing daily on its axis, although apparently unmoving. Geology
in like manner begins with even more unpleasant truths, and
convinces us that the present configuration of the continents and
seas, so far from being the primeval condition of things, is but one
of the various vicissitudes through which the world has passed.
We are accustomed to consider the earth as coeval with man,
and that but five or six thousand years have elapsed since their
creation. Geology demonstrates that our present abode is of far
greater antiquity, and the slightest examination of the crust of the
earth will convince us, that the substances of which it is com-
posed, are the results of accumulations or deposits extended
through a long period of cycles. As we have already observed
all the strata, with the exceptions of the igneous rocks, the granite,
the gneiss, and the mica-schist systems, are fossiliferous, and it
is highly probable that even these rocks are of sedimentary ori-
gin, and once contained the remains of organic matter. The
vast series of other deposits are the undoubted mineralized beds
of primeval oceans, with occasional interpositions of lacrustine
or lake formed, and fluviatile or river deposits, the former rival-
ing those of the vast Atlantic and Pacific, and the latter those of
the immense inland lakes and rivers of the American continent.
We do not find these mineralized beds or rocks, in all cases bear-
ing the marks of quiet, but showing the agency of numerous dis-
turbing influences, they have been upheaved and bent over; and
broken through by the erupted and molten masses from beneath,

JWUiSKRALS AND DOSSILS. 297

Which have rlown up through wide chasms and overspread them.
Intervals of unusual volcanic agency, have been succeeded by
ages of tranquil repose, and these again succeeded by a revival
of former energy. We see in all these vast changes the control-
ing power of an Eternal Mind ; periods of time which man iu
vain endeavors to comprehend, have witnessed continual exhibi-
tions of creative power and wisdom. The diversified materials
of which the earth is composed, have been elaborated into beauty
and order, every object has its sphere of usefulness and action,
and its period of existence is limited. • We have never been able
to perceive at all the grounds for the too hasty conclusion which
some superficial philosophers have adopted, that the present per-
fect system of organization is the result of a progressive develop-
ment of inferior types of existence, and that the remote origin of
all life is the monad or animalcule.

It has ever been the attempt of man to penetrate beyond the
ordinary boundaries, which nevertheless, like the almost impassi-
ble barriers of a deep ocean surround him. Now with his heaven-
directed tube, ho speculates upon the former conditions of all
worlds. Penetrating back to periods of time far beyond the dream
of the geologists, he imagines the wisps of nebulous matte; which
in a clear night, with the most powerful glasses, he can just de-
scry, and which appear as rare and light as the thinnest vapor
which floats in the form of a cloud on a summer's eve, these he
imagines slowly condensing, and gradually forming worlds. The
geologist looks back to the remote and primeval ages when the
first life appeared on our planet, and he uncovers with careful
hand the imbedded remains of fragile plants, and shells, which
have lain hidden in their stony beds for periods of time compared
with which, our years dwindle to utter insignificance.

The whole substance of our globe, at least so far as the solid
materials which compose its crust are concerned, may be divided
into two great classes, minerals and fossils.

MINERALS are inorganic snbstances, and are the products of
chemical or electrical action.

FOSSILS are the remains of organic substances imbedded in the
strata by natural caueee at some remote period, and these remains

THE WOKLD.

are of the utmost importance in the ej^es of geologists. If we
examine the successive beds of water deposits in the various parts
of our country we soon find that peculiar and characteristic fos-
sils belonging to one locality. Or if we penetrate the earth to
such a depth that we reach the strata, which at some distant
place may crop out, or appear on the surface, as explained page
184, we will then find the same fossil remains as would be
found at the surface at that distant place. The inference which
we naturally draw from this is, that if at different ages of the globe,
when the successive strata were deposited, different races of ani-
mals and vegetables flourished, then these fossil remains will
enable us to determine with something like certainty, the relative
ages of the strata which compose the various parts of a country,
for it must be remembered that the rnineralogical character of
most of these beds is the same, and many times no opinion
whatever can be formed from this. Hence these remains have
been appropriately termed the ** Medals of Creation," and they
afford to the geologist precisely the same evidence of the charac-
ter of the period when they existed, and were deposited, as an
ancient coin to the numismatist, of the character of the people,
and the period when it was struck. Oftentimes a single coin or
medal, is the sole remembrance which exists, to determine the
date of a great event, and so a few bones, a shell, or a tooth, or
track of a bird in the sand, are the sole memorials of peculiar
types of existence of the primeval worlds It would seem at first
that from the very nature of the materials which compose most
organic substances, that all traces of them would soon be oblit-
erated. It is true that the soft and delicate parts of animal and
vegetable organisms rapidly decay after death, yet in certain cases*
their decomposition is arrested, and by a peculiar process every
part is transformed into stone; thus, many of the most perishable
vegetable tissues have been preserved, and even in the anthra-
cite coal, which has been burned in the grate, distinct traces of
organic structure can be observed under the microscope. The
woody fibre of vegetables, the bones and teeth of animals, deeply
imbedded in the earth, are thus preserved in some instances with
wonderful accuracy and perfection. Th« perishable fleshy parts

6fc«ANIC REMAINS. '299

of the animal of the Belemnite, a characteristic fossil of the
Oolitic group, have been thus preserved in indurated clays, and of
the cuttle-fish in limestones. The delicate impressions of plants
of the various epochs stamped in the sandstones, shales, coals,
and chalks, are presented with the utmost fidelity. The><eilicious
shells of animalcules are every where abundant; in our own coun-
try whole districts are composed of them; in Virginia, New Jer-
sey, New York, Massachusetts, Michigan, and Iowa, and prob"
ably every state of the Union, their remains are more or less
common. In a previous chapter we have admired the construe-1
tions of the coral-animal, and considered with a feeling of -aston-
ishment and wonder, the immense importance of the labors of so
apparently helpless and insignificant a being; but what shall we
say to the beds of rocks, composed of the remains of animalcules
invisible to the eye ? yet of such are the pyramids built ! Not
only are the carapaces, or shelly coverings, of these minute ani-
mals preserved, but in many instances the fleshy parts of certain
minute chambered shells are admirably preserved, imbedded in
the heart of a flint nodule, and one familiar with such appearan-
ces, can in the merest fragment of flint, detect various organic
bodies. The variety of limestone called encrinital marble, is
composed almost wholly of a peculiar stony animal called the
Encrinite. and particularly abundant in the carboniferous, or
mountain limestone, of the carboniferous group. A specimen
from the Helderbergh Mountains near Albany, lies before us,
compact and firm as though originally composed of crystaline
materials. The ordinary observer can form but little idea of the
amount of organic remains distributed throughout the various
strata.

In the following chapters we shall consider in order the three
great epochs, or periods of the earth's existence as demonstrated
from the study of fossil animal and vegetable remains. The first
epoch commences with the granitic period, or period antecedent
to the introduction of life, and ends with the carboniferous or
great coal formation. The second period commences with the
new red sandstone, and ends with the cretaceous or chalk system .
The third and last period embraces what are termed the tertiary

300 THE

deposits. We would refer the reader to the chart on page 194,
where these divisions will appear marked according to Dr. Buck-
land, under the names primary, transition and secondary, and
tertiary. It will only bo passible to give a very superficial sketch
of the probable condition of our planet during these several
epochs, but we shall endeavor to convey a clear idea of the suc-
cession of animal and vegetable life which so strongly character-
izes them, so that the reader will be prepared to enter upon a
more extended investigation.

It is almost impossible even when writing upon ordinary topics^
to avoid the use of technical terms, and perhaps least of all can
this use be avoided, when natural history becomes the subject.
There is nothing of so much benefit, both in economising the
time of the student,and in assisting his memory, as a correct and
intelligible system. A well selected name, expressive of pecu-
liar characters, or habits, or localities, conveys a multitude of
ideas to the mind, which a common or vulgar name would en-
tirely fail to do, for this reason we shall use the names generally
applied by geologists to the several fossils, giving in all cases,
their meaning or translation, whenever these words are derived
either from the Greek or Latin. The word fossil, which we have
often used, meant originally, what was dug out of the earth, it is
now however applied only to the remains of organic matter.
The fossil animal kingdom may be divided into six sections.

I. INFUSORIA, or Animalcules. The name infusoria is derived
from the presence of many genera, or groups of species, in vege-
table infusions, not easily observable without the microscope.

II. ZOOPHYTES, or Animal Vegetables, a term applied to corals
and other animals supposed to resemble plants; the subdivisions
of this group are,

1. AMORPHOZOA, or animals of no regular shape like sponges and

2. POLYPARIA, or many producing animals as the corals.

III. ECHINODERMA, or spiny skinned animals, subdivided into,

1. CRIKOIDEA, or Encrinital, i. e. lily or cup-shaped animals.

2. A«TERIA, or btar'formed, like the star-fish.

3. ECHLXIOA, or spiny animals* like the sea-urchin, or sea-egg;.

DIVISION ®? THE ANIMAL KINGDOM. 301

IV. MOLLOSCA, or soft bodied animals, destitute of bones, uu-
'der this head are embraced the fossil shells.

1. BIVALVES, or consisting of two pieces like the oyster and clam.

2. UNIVALVES, or consisting of one shell like the snail and peri-
winkle; these latter are the true molluscs, and are of a
higher degree of organization than the former, possessing
a head and eyes, of which the former are destitute.

3. CHAMBERED shells like the nautilus, including both the tes-
taceous or shell covered genera, and naked molluscs as the
cuttle-fish.

4. CIRRIPEDIA., or hairy-footed animals, like the barnacle.

V. ARTJCULATA, or jointed animals, comprising,

1. ANNELATA, or ring ed animals, like the red blooded worm.

2. INSECTA, or insects, i. e. having the body nearly divided in
two, like the wasp and fly.

3. ARACHNIDA, or spiders.

4. CRUSTACEA, having a crustaceans skin like crabs and lobsters.

VI. VERTEBRATA, or animals having a spinal column or back-
bone, subdivided into,

1. PISCES, or fishes.

2. REPTILIA, or reptiles.

3. AVES, or birds.

4. MAMMALIA, or animals giving suck.

The animal kingdom is divided into the above great classes-,
"and these are subdivided into a vast number of species, each being
characterized by some peculiar and distinguishing mark. The
expert anatomist can often from the mere inspection of a tooth,
or a claw, determine the character and habits of an animal. Of-
tentimes this, or even a foot-print in the sand, is all that remains
of some now extinct creature, yet by analogy, instituting a rigid
and close comparison with existing species of the same gen-
era, the peculiarities are distinctly made out, and many remarka-
ble facts are brought to light. We now proceed to consider the
probable condition of our planet during the stages of existence
before enumerated.

305 THE

CHAPTER Xlil
The first Epoch.

"The land that hath no summer flowers,-
Where never living creature stood;
The wild, dim, polar solitude:
How different from this land of ours ! "

Mary Howitt.

THE first great period, commences with the granitic and ends
with the coal formation. Beneath the most ancient deposits lies
a crystaline rock which, under the name of granite, is familiar to
to every one. Lofty mountain chains, sometimes rearing their
Alpine summits far beyond the limit of perpetual snow, look
down in solitary grandeur upon the scenes below. The hardest
and most indestructable of all rocks, it seems fitted for the foun-
dation or superstructure of the entire mass. Occasionally it is
found of a more recent origin, exhibiting the appearance of hav-^
ing been ejected after the deposition of the newer strata; probably
the result of intense heat acting under great pressure. We may
suppose then that there was a time, "the beginning," when a
globe existed having alternations of stone and water, no soil was
upon its surface, which was a bare rock, presenting innumerable
rugged peaks; not a sea-weed floated in the waters, nor a lichen
grew on the rock; no sound was there except the monotonous and
angry dash of the waves upon the bare and desolate coast. But
even then, the atmosphere, perhaps surcharged with carbonic acid,
was actively engaged in crumbling down the barren rocks, and
we may suppose that the waves and the winds urged their com-
bined force as now; the fragments of granite thus torn off, were
deposited -in the bed of the ocean, and we find them compacted
under the name of gneiss. If during this action, the felspar was
partly decomposed, then the quartz or silex, would be deposit-

BASALTIC COLUMNS.

303

eti alone, and subsequently the felspar and mica, either in the
form of mica schist, .which is composed of layers of mica and
quartz, or slaty rocks without fossils; these are the strata which
lying immediately upon the granite, and presenting marks of
aqueous deposition, yet partake more or less of the crystalino
character of the primitive rocks. During all the long period of
the deposition of these rocks, formed from disintegrated granite,
not a living thing moved, either on the dry shores or in the deep.
Perhaps a few animalcules existed in the clear waters, but we
have no distinct traces of them; all was silent, the stillness of ab-
solute death. During this period however, great volcanic con-
vulsions occurred, the yet soft masses of gneiss and_ schistose
slates were Upheaved, and in many cases rent open and molten
masses of granite and basalt flowed through. The metals, melted
by the intense heat, were injected into the narrow fissures, and
innumerable dykes and veins were formed. In some instances
the masses of melted trap rock have crystalized upon cooling, in
regular hexagonal prisms. Such are the columns which compose
the celebrated Fingal's Cave, exhibited in the wood-cut below.

Directly associated with the contorted masses of mica schist to
which we have just alluded, there is a coarse slaty rock, exhibit-
ing still more clearly the marks of aqueous deposition, but by far
the most interesting circumstance connected with this deposit,
is the first appearance of animal life. We must consider with
no little interest, the fossil remains of these early rocks, among

304 'iii

llieiu are found peculiar species of shells, and alow corals, but a.s
yet, nowhere throughout the whole world, in this immense de-
posit called the Cambrian, (page 191), has the least fragment
been found referable to a fish; nor any traces of aquatic plants,
except a few sea- weeds; nor vcrtebrated animals. It is therefore
pretty evident, that at this time, either they did not exist, or if they
did, it was in extremely small numbers. We find the lowest or-
der of organization here developed, in the remains of a zoophyte,
or animal plant figured below, which is analagous to the sea-pen,

and termed by Mr. Murchison, who has investigated with great
care, this series of rocks, graptolii&s, from the peculiar markings
of the stone; these were probably formed by an assemblage of a
vast number of individual polypes, each having a separate exis-
tence, but yet connected with the general mass, they are found
in great abundance in the.United States. There are also many
species of coral common in the most ancient rocks, and similar
in most respects to those now existing in the Indian Seas. The
low organization of these coral polypes has probably enabled them
to survive all the changes through which, so ofien the world has
passed, and we find them at the present moment as busily em-
ployed as in the earliest periods of the earth's existence. The
Silurian rocks are extensively developed over the whole world so
far as geologists have been enabled to explore. The immense de-
posits of calcareous flags, sandstones, shales, and limestones,
furnish our most valuable stones for economic purposes. As we
advance upwards in the series of deposits we find a marked
change not only in the mineralogical character, but in the num-
ber and form of the organic remains. Among the peculiar ani-
mals which flourished at this stage of the world's existence were

ENCRINITRS AND TRILOBITES.

305

the Crinoidal, or lily-shaped animals, so called from a fancied re-
semblance to a lily, they are somteimes termed Encrinitzs. We
here figure two specimens, one closed and the other open. There

are a very great many varieties of encrinites, some of the most
beautiful occur in the new red sandstone group, figure 1, is
called the pear encrinite, fig. 2, the tuberculated; they consist es-
sentially of a stony case, supported on a slender jointed stalk,
and are found in all positions and in immense numbers, but they
are of a much higher organization than the coral polype. An-
other very peculiar fossil of this epoch is the trilobite, so called
from the body consisting of three distinct lobes. We here repre-
sent one of these animals; they are found in abundance in the

older strata, and of many distinct generic forms; they probably
possessed sliDrt legs and were destitute of antennae, the eye how-
ever, was the most remarkable feature. It was immovable, but to
compensate for this it was exceedingly prominent and provided
with many hundred lenses, precisely similar to the eye of the

300

THE WOIU/D.

dragon-fly, and the house-fly. Among the moluscs, or soft
bodied animals, we find one very common and characteristic of
this period, but now entitely extinct, it belongs to the same fami-
ly cephalopoda, i. e. having the arms or feet near or upon the
head, ns the nautilus, and is called the ortlwcerai itc, or straight
horned animal and is figured below, nothing is known of these

except the fragments of their former habitations, some of them
are slender and pointed, others nearly straight, and they are oc-
casionally found of great size. Such were the inhabitants of
the globe during its early periods, while yet no fishes swam in
its waters, or animals roved in forests upon the shore. Trilobites
swarmed in innumerable multitudes; the crinoidal animals were
attached to every fragment of rock; and the voracious cephala-
poda roamed through the deep. Day and night then as now suc-
ceeded each other, and year after year passed on, but who can
tell, or who can estimate the ages which rolled away from the
commencement of the period we have been considering to the
close of those immense deposits called the Silurian. But the
dawn of a new era was now commencing, and the great and im-
portant natural class of fishes were about to be introduced, though
with such marked peculiarities and singular forms, and so differ-
ent from any now living that they almost seem allied to the crus-
taceans, or to the reptiles. One of the most singular, with
long bony fins, is called the PtcricklJnjs Cornutus, or horned wing-
ed fish. It was of small size, the head and body being covered
with strong plates of bone coated with enamel. Another singu-
lar fish called Cephalapsis, or buckler-headed, possessed an enor-
mous buckler head, similar to the cephalic shield of certain trilo-
bites. It bus been compared, and not unaptly, to the crescent
shaped blade of a saddler's cutting knife, as will be seen on ref-
erence to the engraving on the following page.

There are many other varieties or groups of fishes belonging

GANOID FISHES. 307

to this period which we cannot name here, but most of them be-
long to the two great classes designated by M. Agassiz, the Pla-

c,oid, or plated; and the Ganoid, or shining, or enameled. The
first class, is at present represented by the sharks and rays, and
the second by the sturgeon and bony pike. The former or Pla-
coid, were first introduced, but w«re comparatively small and
feeble, but the latter, during the Devonian, or old red sandstone
period, (see page 190), were very abundant. It is somewhat re-
markable that this group of fishes is now represented by only two
species, the American Gar-pike and the Birchir of the Nile; no
less than sixty distinct species being found in the old red sand-
stone. No traces however, of those groups of fishes, now so
abundant, are found in these strata. Leaving this remarkable
period, when the waters teemed with formidable and singular
shaped fishes, we find the commencement of a new epoch in the
appearance of an immense deposit of carbonate of lime, in the
form of the carboniferous or mountain limestone, and the varie-
gated marbles; imbedding a remarkable number of vegetable fos-
sils, which indicate not only the presence of land, but the exis-
tence of a luxuriant and tropical vegetation. The carboniferous
limestone, is in many cases the result of the labors of the coral
insect, indicating the presence of a shallow sea- bottom and warm
temperature. Immediately in contact with the coraline lime-
stones is a coarse sandy conglomerate used for millstones, and
called the mill-stone grit, which is succeeded by strata of shale
and sandstone, with occasional seams of coal; after which, follow
the coal measures, so called, being large deposits of bituminous
coal. But little doubt can exist as to the vegetable origin of di
coal; it is true that the most perfect bituminous coal has under-

30&

THE WORM*.

gone a liquefaction which has destroyed its organization, but IB
the slaty coals and the shales, traces of cellular tissue are obser-
ved, and the peculiar spiral vessels and dotted cells, indicating
the coniferous or cone-bearing wood. We must therefore con-
clude that these beds of coal, although mineralized, and almost
crystaline in their appearance, are entirely of vegetable origin.
Among the fossils of the coal there are a great variety of ferns, and
some of them of very elegant forms. We here give figures of
two species, fig. 1, is from the coal shales of Ohio, called the

2 1

Pecopteris Sillimanii^ or Silliman's embroidered fern; and fig. 2»
the Sphenopt&ris, or wedge-leafed fern; from the coal shales
Silesia. Besides the fern tribe, which in the ancient world seems
to have been ranch more largely developed than at present, wo
find gigantic specimens of the Calamite, similar in all respects
to the common reed growing abundantly in our marshes and
called Equisclum, or marestail.

Notwithstanding the extensive beds of coal found everywhere
over the globe, no trace or fragment of quadruped, bird or rep-
tile, has been discovered. The immense forests of aborescent
or tree ferns, and coniferous trees with their rich and luxuriant
vegetation, were desolate and silent; no reptile crawled over th»
damp ground, no bird made a nest among the green foliage, no
sound broke the primeval silence, which for ages shrouded the-
the thick forests; silently theysank down b&neath the waters, aiuS

CLOSE OK THE FIRST EPOCH.

in the lapse of ages other strata enveloped them, and preserved
the forms of their delicate leaves, and the markings of their
trunks and stems, for the inspection of long succeeding ages.
But all this time the sea was alive with its multitudes of corals,
of echini, trilobites, and peculiar cephalopods, and fishes. It
was during this epoch, that the ganoid fishes were most highly
developed, and innumerable sharks of all sizes abounded in the
carboniferous seas.

We have now arrived at the end of our first epoch, just before
the introduction of reptiles. There seems in some respects to
have been a progression in organization, and yet, not such as to
support the view, however plausible, of the agency of an inferior
type of organization in introducing a higher group. The corals
and the encrinites still remained with but little change, but the
trilobites were nearly extinct, the cephalapodous animals, retain-
ing till now the straight and elongated form of the orthceratites,
assumed the spiral form of the goniatite. The small fishes of
the early epochs gave place to large and voracious species, pow-
erful swimmers and insatiably voracious; vast tracts of country
were settling down, and the rich, and rank vegetation,, which cov-
ered the land at the time of the coal epoch, was prepared for the
first stage of its change into coal. During all this period, wo
must not fail to note the entire absence of all the grasses, which
now form so prominent a portion of existing plants ; indeed,
the whole face of the globe, was so entirely different from its
present appearance, that could we now behold it, we might
realize that we were looking upon another planet. It is not for
us to discuss the question of the length of time necessary to ac-
complish all those changes which the globe has passed through,
or to speculate upon the distinct efforts of creative power ex-
hibited throughout those countless ages. It is sufficient for us
to know that myriads of beings, dissimilar to any now existing,
or only remotely connected, flourished perhaps for thousands of
years, when suddenly they disappeared, and quite as suddenly
new forms replaced those lost. There can be no way of account-
ing for these changes in the forms of animal and vegetable life,
except by the direct interposition of a creative power.

310 THE woui.r.

CHAPTER XIV.

The, second Epoch.

" And later yet the sea o'erspread
The spot where now we walk ;
And this was once aa ocean's bed,
The ocean of the chalk." Anon.

THE epoch now to be considered, is in many respects the most
interesting, as it is certainly the most abundant in its fossil re-
mains. In our present volume we can only glance at the char-
teristic features, leaving wholly untouched those minor details,
which often make the most interesting part of a history. We
can therefore only hope that the reader will make a beginning
here, but search elsewhere for more extended and minute infor-
mation. Immediately above the«coal measures, lies a coarse sandy
deposit, which appears to be the ruins of some more ancient rock,
consolidated by pressure and the infiltration of water impregnated
with iron. The shores of the previously existing lands, seem to
have gradually been depressed, forming vast beds of coal; upon
these, the beds of sand and marl were loosely and rapidly de-
posited, and are not exceedingly rich in their fossil remains.
There is however, one interesting and remarkable fact connected
with these deposits, and that is, distinct tracks of reptiles and
birds; to these we shall allude again presently. The lowest
member of the new red sandstone group is the magnesian lime-
stone, so called from having a considerable portion of carbonate
of magnesia mixed with its carbonate of lime; it is a stone ex-
ceedingly valuable for building purposes. This limestone con-
tains a few fossils, corals and shells, and occasionally a few frag-
ments or whole skeletons of fishes. The fishes are all remarka-
ble for a peculiar structure of tail characteristic also of the fishes
of the older strata, this structure is called by M. Agassiz the hcte-

FOSSIL FOOT-STEPS.

rocercal, the tail being unequally lobed as in fig. 1, which is the
tail of the shark, and the vertebral column running along the
upper lobe. On the other hand, in nearly all the living species,

the tail is homocercal as in fig. 2, which is the tail of a herring,
the vertebral column not extending to the upper lobe.

We have remarked that the first tracks of reptiles are met with
in this system of deposits. Below we represent the appearance
of these footprints as observed in England and Germany. It

will be perceived that there are two impressions which always
accompany each other, and they are not unlike the human hand,
hence the animal was named ckeirotherium or hand beast. This
animal was for a long time supposed to be allied to the kangaroo,
and like it a marsupial, i. e. having a pouch in which to carry its
young; but more recently Prof. Owen, from a careful examina-
tion of teeth and other bones found in the new red sandstone, has
determined it to belong to the class of batrachians, or frogs, toads,
salamanders, &c., and from the peculiar structure of its teeth,
ho has given to this genus the name labyrinlhodon, or labyrinth
tooth. Besides the tracks just described, are found those of tur-
tles, of a little lizard with a bird-like beak, and the trails of
molluscs, and vermes, and the ripple marks of the ancient seas.
By far the most remarkable tracks occurring in the new red sand-
stone group, are those of gigantic birds, the foot-prints being sev-
enteen inches long, and the stride of the bird from four to six
feet. It is somewhat remarkable that nearly all the fossil foot

312

THE WORLD.

marks yet discovered, occur upon some member of the new re*3
sandstone grotrp. On the same stone are impressions of raia
drops. "It is a most interesting thought," observes Prof.
Hitchcock, M that while millions of men who have striven hard
to transmit some trace of their existence to future generations,.
have sunk into utter oblivion, the simple footsteps of animals,
that existed thousands, nay, tens of thousands of years ago,
should remain as fresh and distinct as if yesterday impressed;
even though nearly every other vestige of their existence has-
vanished. Nay still more strange is it, that even the pattering
of a shower at that distant period, should have left marks equally
distinct, and registered with infallible certainly the direction of
the wind/' When these foot prints were first discovered their
enormous size seemed an insuperable objection to the opinion that
they were bird tracks. But recently in the island of New Zea-
land, the bones of an immense wingless bird have been found to
which the name Dinornis, or terrible bird, has been given. Be-
low is an outline representing the size of this extraordinary ani-
mal compared with a man.

Immediately above the new red sandstone in some parts of th e

THE PLESIOSAURUS.

313

world, but particularly in England, is deposited a fine sandy and
marly stratum, consisting- of distinct layers with occasional lime-
stones, and exceedingly abundant in remarkable fossil remains.
To this the name Lias has been given, and the reptilian remains
imbedded in it are the most magnificent objects of the Creator's
hand. During the deposit of these muddy beds which were un-
favorable to the growth of corals, we find but few traces of these
animals, but on the contrary the crinoidea, already alluded to,
were developed in singular and beautiful forms, and also very
peculiar forms of the cephalapodic group. Among the marine
reptiles of the epoch we are now considering, two are particular-
ly noticeable. The Pl&siosaurus, or almost lizard, and the Ichthy-
osaurus, or fish lizard. Below we represent the plesiosarus, which
possesses a head small, and lizard-like, with teeth like a croco-

dile, a neck of enormous length like the body of a serpent, and a
back and tail having the proportions of an ordinary quadruped.
It is furnished with four paddles, and is supposed to have inhabi-
ted the shallow waters; darting by means of its long neck, sud-
denly at the fish which came near it. The largest complete spe-
cimen of the plesiosarus yet discovered is about eighteen feet in
length. Fierce and voracious as this animal undoubtedly was, '
yet it had an enemy in the ichthyosarus represented in the follow-
i ng wood cut. This formidable marine reptile sometimes attain-

ed to a length or thirty or forty feet, and like the whale possessed
a smooth and naked skin. The eyes were enormously large and
provided with bony plates, or divisions arranged around the pupil-
There are instances where the diameter of the orbit is eighteen

314 THE WOULD.

inches across. The jaws are long and furnished with sharp coni-
cal teeth, resembling1 those of the crocodile, and like them re-
placed continually, as they become worn, by new ones ; the fins
or paddles werofour. Both these remarkable animals, now en-
tirely extinct, are figured in the frontispiece of the present vol-
ume, which is designed to represent the condition of our globe
during the period we are now considering.

Above the lias shales is a deposit which seems to indicate great
changes in the organic world, caused by the elevation of wide
tracts of country over certain portions of the globe, attended with
numerous depressions in other parts, and the strata deposited
during these movements seems to have formed the bed or final
depository of many successive races of beings. The name Oo-
lite given to this group of deposits signifies egg-like stone, be-
cause it is formed of small egg-like grains, like those comprising
the roe of a fish, the nucleus of which, on microscopic examina-
tion, appears to be some minute organic substance, usually a frag-
ment of coral, or a shell. To this class belong the so-called
Oxford and Kimmeredge clays, and the Jura limestone, since the
mass of the Jura mountains in France is of the oolite formation.
During this period, an immense number of marine animals flour-
ished, most of which are now entirely extinct, among them are
peculiar corals, star-fishes, and sea-eggs or echini. Below we
give a representation of a very perfect crustacean, similar to the

lobster, from the oolite clay of Yorkshire, England. The fossil
remains of insects are also common in these strata, and very pe-
culiar and beautiful forms of ammonite, which seen?? to have

THE BELEMNITE. 315

been most perfectly developed in the lias seas. We have before
described a cephalapod called the orthoceratite, (page 306), sub-
sequently we find this animal displaced by one with a curved and
somewhat angular shell during the carboniferous formation, still
later "during the deposition of the lias and oolitic beds, we find
another change under the form of the ammonite; at the same
time the nautilus, a well known cephalapodous animal, closely
related to the ammonite, was likewise abundant. The nautilus
still inhabits our tropical seas, and unfolds its fleshy sails to the
gentle breezes, but long since the ammonite has been extinct.
Another of the same class or group of animals, and which is now
represented by the cuttle-fish, is the animal of the belemnite.
The fossil called the be\emnit& from its resemblance to a dart or
javelin, is not uncommon, and is found of various lengths and is

sometimes called by the singular names of the devil's toe-nail,
thunderbolt, &c.; the general appearance of the fossil is howev-
er as represented in fig. 1, and perhaps no organic remains have
ever caused more ludicrous mistakes, or given rise to more fanci-
ful theories. It is the internal skeleton of an animal very much
like the cuttle-fish, and represented in fig. 2. From the fossil re-
mains, this animal appears to have been exceedingly large and
formidable, preying upon the smaller fishes and reptiles, it was
furished with eight long arms, each provided with from fifteen to
twenty hooks; the eyes were large and the jaws powerful. Like
the common squid, it seems to hnve been provided with an oval
sac, containing a dark fluid, ejected by the animal when alarmed
in order to discolor the water aud facilitate its escape. During

316

THE WORLD.

this period the plesiosaurus, and the ichthyosaurus abounded, and
in addition we find another marine monster rivaling the largest
whales in size, possessing webbed feet armed with strong claws.
The flora of the carboniferous period, we have observed, con-
sisted mostly of ferns, and large coniferous trees, of gigantic di-
mensions, and of calamites, and numerous other plants the
exact nature of which is not yet determined; but in the lias and
oolitic formations an entirely new race of plants covered the earth.
The ferns, which formerly constituted two-thirds of the entire
species known, were greatly diminished, and the calamites and
palms all disappear. Coniferous plants were still very common,
but of different species from those of the earlier epochs, and
plants analagous to the Cycadese and Zamias of the tropical re-
gions seem to have replaced the ferns. The wood cut will give
a tolerable idea of the character and appearance of the flora of

the oolitic period. During this Age of Reptiles, as it has been
termed, one of the most marvellous beings, and which for along-
time caused no little speculation and discussion among philoso-^
phers, flourished in considerable numbers. It has been termed
the Pterodactyle, or wing-toed animal. ' (See next figure). This
flying reptile, possessing the head of a bird, the wings of a bat,
and the body and tail of an ordinary mammalian, appears to be a

THE PTERODACTYLS. 317

sort of connecting link between the three great groups, reptiles,

birds, and mammals. It seems to have been capable of walking
with ease upon the ground, of perching on trees, and of flying
swiftly through the air. The teeth of the pterodactyle are long,
pointed, and slender, from twenty to thirty in each jaw, and like
the crocodile replaced by new ones when worn. — While the cal-
careous oolitic beds were being deposited in the sea, there seerns
to have been in some parts of the world, but particularly in the
southern part of England, immense rivers, with extensive estu-
aries flowing over vast tracts of countries, and bearing down
upon their waters and imbedding in the mud and silt of the shoal-
ing estuaries, the remains of land plants and animals, and fresh
water shells. To the beds or deposits thus made, the name
Wealden has been given, (seo page 188). With the exception
of the plants of the coal epoch, this deposit is almost the sole evi-
dence of the ancient land and its inhabitants. It is somewhat
remarkable that among all the previous deposits no trace of any
true quadruped has been found, all the remains belong to marine
4^1and reptiles, and up to the time of the Wealden formation no
traces except the few tracks on the new red sandstone, are found
of birds. Dr. Mantel), who has so successfully investigated the
geology of the south-east of England, has however in the latter
flamed strata, discovered many fragments of bones supposed to

318 THE WORLD.

belong to birds allied the Heron. Among the reptiles character-
istic of this deposit the most remarkable is the Iguanodon, so
called from the resemblance of its teeth to those of the Iguana,
a recent West Indian lizard. This gigantic suarian, or lizard, was
upwards of 70 feet in extreme length; the circumference of body
14£ feet; length of tail 52£ feet; and of the hind foot 6| feet. In
the British Museum, is a thigh bone of an Iguanodon, which is 3
feet in length, and eight inches in diameter. We cannot easily
conceive of a reptile of such hu^e dimensions; surpassing in
height the tallest elephants, and far greater in bulk than any
known living animal. A reptile of the same class, called the
HylfEosaurus, or lizard of the Weald, was likewise discovered by
Dr. Mantel]; in dimensions it was somewhat less than the igua-
nodon, and armed with a row of spiral protuberances, and scaly
plates.

During the deposit of the chalk, a vast multitude of fishes
swarmed in the waters, among those were immense sharks,
whoso remains are plentifully found. How different the scenes
then enacted, both on land and in the sea, from now. While
upon the land, gigantic reptiles prowled through the dark woods,
or along the chalky shores, covered with alligators and turtles;
and the pterodactyle glided swiftly amid the dark foliage in pur-
suit of its prey ; the icthyosaur, the plesiosaur, and voracious
sharks roamed through the deep, devouring multitude1!! of smaller
animals. Upon the surface of .the waters, the nautilus and
ammonite still sailed, and the sea egg rolled over the smooth bot-
tom. Then, as now, the coral insect toiled on, and thousands of
encrinites waved their flexile stems in the heaving waters
Scenes like these, for ages, were witnessed upon the face of our
planet, but we cannot begin to estimate the lapse, not of years or
centuries, but of myriads, ere the change came which swept
them forever from among the living things of earth, entombing
them for memorials of those remote ages, which should
language too plain to be misunderstood, that many times,
the earth first commenced its revolution around the sun, changes
have passed over its surface which would bo more than sufficient
to sweep away every living thing which now moves upon it.

THE THIRD EPOCH. 319

-

CHAPTER XV.

T/ie Tertiary Period.

"Yes ! Where the huntsman winds his matin horn,
And thecouch'd hare beneath the covert trembles;
Where shepherds tend their flocks, and grows the corn;
Where Fashion on onr gay Parade assembles —
Wild Horses, Deer, and Elephants have strayed,
Treading beneath their feet old Ocean's races."

Horace Smith.

WE are now to consider the last great epoch, called the tertiary
period, commencing immediately aftei the deposit of the chalk,
and ending with the appearance of man. The tertiary strata
consist of a vast and varied series of deposits, fluviatile, lacrus-
tine, marine and volcanic, but they are all deposited in hollows
or depressions, usually of the chalk, and occasionally cf the older
rocks, a,nd afford distinct evidence of important changes in the
relative level of land and sea, during the period in which they
were deposited, and they likewise show that volcanic agency was
developed at this period on a vast and magnificent scale. From
the remains entombed during this epoch, it is pretty evident
that the climate of the ancient world was much milder than at
present. Be this as it may, it is a fact indisputable, that not only
the bones of hyenas, bears, lions, and tigers, are found in coun-
tries where now they could not live, but also several varieties of
palms and pines ; and even as far north as the 70° of latitude,
the remains of the elephant and rhinoceros are found imbedded
ij^he ice. During the tertiary epoch, the Ganoid and Placoid
groups of fishes, so characteristic of the earlier deposits, were al-
most extinct, the latter class being represented by a few sharks
and rays, while by far the greater number were allied to existing
species. The remains of birds; skeletons, feathers, and even their

320 THE WORLD.

egg's, are found in good preservation — they are allied to present ex-
isting species. On the island of New Zealand, an immense num-
ber of fossil bones of birds have been found ; we have already al-
luded to one of these, the Dinornis, page 312; the beak of this
bird was shaped like a cooper's adze, and admirably adapted for
tearing up roots ; they were, as Dr. Mantel! remarks in a letter to
Prof. Silliman, " glorious bipeds, .some ten or twelve feet high."
In the tertiary strata of the Paris basin, Cuvier found the remains
of several thick skinned animals allied to the tapir, and of others
forming a connecting link between the tapir and the ruminants,
or animals chewing the cud — some of these were of very pecu-
liar forms. A remarkable animal, characteristic of the middle
tertiary period, was the Deinotherium, or terrible beast, figured in
the engraving below This huge animal dwelt probably in

marshes and swamps, and was nearly twenty feet long ; the legs
are supposed to have been nearly ten feet in length, the head was
of proportional size, and furnished with two large tusks fixed in
the lower jaw, which probably, served ihe purpose of pickaxes, to
dig out the roots upon which it fed, and perhaps to anchor it by
the side of the bank at night. In Russia and Siberia, remains
of ihe elephant and rhinoceros have been found entombed in ice,
together with birch trees, far beyond where even stinted bus
now grow. The tusks of the fossil elephants are found in th(
high hills above the sea level, in clay and sand frozen as hard as
a rock, and increasing in abundance as we proceed north. For
about a century they have been brought away in immense num-

KOSSIT. ELEPHAN'i. 321

ber.s, yet with no perceptible diminution of the stock ; doubtless
many of these animals were drifted down towards the arctic seas
by the immense rivers which'flow northward into the icy ocean.
The subjoined figure represents the skeleton of the celebrated,
elephant discovered by a Tungusian fisherman, in the year 1790,
in. the banks of a river in Siberia, in which it had been frozen up
for ages. The skin of this animal was of a dark grey color, and

covered with reddish wool. The two tusks, together, weighed
three hundred and sixty pounds, and the head alone, four hundred
and fourteen pounds ; the flesh of this antediluvian was in such
perfect preservation, that the dogs, white bears, wolves and foxes
fed upon it. The eyes were well preserved, and the pupil in one
of them could be distinguished. The fossil Siberian elephant
differed but little from the one now inhabiting India, except in its
wooly covering ; its food was probably twigs and branches, in pur-
suit of which, herds of these gigantic quadrupeds probably mi-
grated far north. The remains of elephants are very widely dis-
tributed ; they are found in England and various parts of Amer-
ica ; the teeth of the elephant may be readily distinguished from
those of the mastodon, another large hebiverous animal belong-
ing to this period, by a peculiar structure we will now describe.
"We here represent the teeth of the recent and fossil elephant ; a
the African, b the Indian or Asiatic, c the Siberian or fossil. In
the first variety, (a} the enamel is arranged in lozenge -shaped
figures, and in the second (b) in narrow transverse bands, very

322

THE VVOHLi).

similar to the fossil species c; these teeth are composed of three

%MAtt •

-?SM fSSA

BBH mmm -

different substances ; the enamel, exhibited by the white Io2^
enges or bauds, and which extends quite through the tooth to the
roots ; the ivory inside of the lozenges, and the crusia pelrosa or
stony crust outside. The tooth of the mastodon represented be-
low, consists of ivory and enamel only ; the enamel being spread

over the crown of the tooth, its structure is similar to that of
the hog and hippopotamus, fitted for bruising and masticating
crude vegetables and roots. The bones and teeth of the mastodon
are found all over North America, and many entire skeletons
have been exhumed, in some of which, the remains of branches
and twigs undigested have been found. The remains of these
animals are particularly abundant in those marshy tracts, abound-
ing in salt and brackish waters called licks. The mastodon was
not unlike the elephant, but was somewhat larger, and probably

THK MEGATHERIUM. , J2J

much more powerful. While in England and various parts of
the eastern continent, the elephants were congregated in im-
mense numbers, and the plains of North America covered
with herds of mastodons, another and more singular animal,
allied to the sloth, lived in the forests of South America ; we re-
fer to the Megatherium, or great beast. In the museum at Madrid,
there is a perfect skeleton of this animal, whose massive propor-
tions strikes the beholder with astonishment; it is represented
in the wood-cut below, and the proportions will be recognized on

comparing the figure with that of an ordinary sized man, drawn
to the same scale. Its length is nineteen feet, breadth across the
loins, six feet, and height, nine feet. The feet of the hind legs
set at right angles, as in the bear; the heel projects behind, fifteen
inches, and the toes, armed with long claws, about twice that dis-
tance forward : so that a proper base is afforded for the support of
the immense body. The teeth of the megatherium were con-
stantly renewed. This apparently unwieldy animal is allied to
the sloth, but differs from it in the immense strength and mas-
si veness of its posterior portions. It is supposed they fed upon
the foliage of trees which they were enabled to uproot by their im-
mense strength. This idea is confirmed from the fractures of the
skull observed iu some of the specimens. Contemporary with
the megatherium, were several other allied species, which ranged
through the luxuriant forests of South America, while in England

3M TJElE VVORLD.

were herds of deer and wild elephants. In Ireland, the fossil re-
mains of an enormous deer, surpassing the largest elks in size, are
found imbedded in the peat bogs. The expanse of the horns in
some of the specimens is sixteen feet. There is reason to believe
that this animal, though now entirely extinct, existed after the in-
troduction of the human race, since skulls have been found frac-
tured in front, as by the blow of some heavy weapon, and asso-
ciated with artificial remains. The small Irish ox, or bison,
was probably identical with the auroch of Lithuania, which is
only preserved from utter extermination by a stringent ukase of
the Czar. At the same time, most of the existing species of ani-
mals and vegetables flourished m great numbers. The earth was
teeming with life and fitted for the habitation of man. The va-
rious races which from time to time succeeded each other on our
planet, had performed their allotted tasks. The whole system
uniformly and without interruption, seems to have been matured.
The light soil deposited upon the harder rocks, and in the hollows
of ancient lakes, was gradually elevated* forming the present
continents and islands. How long the present stage of the earth's
existence may last, no one can pretend to answer. In all the
changes which have heretofore swept races of highly organized
'' beings from the face of the globe, we see the quiet action of laws
'now in force ; no sudden catastrophe is needed, but silently the
change goes on.

" The Earth has gathered to her breast again,
And yet again, the millions that were born
Of her unnumbered, unremembered tribes."