The next triumph was the boring of four wells in the desert of Morran,

where previously no spring had existed. In the full expectation of

success, everything had been prepared to turn this new source of wealth

to immediate use, and part of a nomadic tribe instantly settled on the

spot, and planted 1,200 date-trees. A dreary solitude was changed, as if

by magic, into a scene of busy life.

These few examples suffice to show the vast services which Artesian

wells are destined at some future time to render to many of the arid

regions of Africa. Both in the Sahara and in the basin-shaped deserts,

which extend, under various names, from the Cape Colony to the

neighbourhood of Lake Ngami, there are, beyond all doubt, numberless

spots where water, the fertilising element, may be extracted from the

bowels of the earth.

In the droughty plains of Australia also a vast sphere of utility is

reserved to the Artesian wells. Here, also, they will subdue the desert,

unite one coast to another by creating stations in the wilderness, and,

with every new source which they call to life, promote both material

progress and intellectual improvement.

[Illustration: MIDDLE AND VALLEY LAKE CRATERS, MOUNT GAMBIER, SOUTH

AUSTRALIA.]

CHAPTER VI.

VOLCANOES.

Volcanic Mountains—Extinct and Active Craters—Their Size—Dangerous

Crater-explorations—Dr. Judd in the Kilauea Pit—Extinct Craters—Their

Beauty—The Crater of Mount Vultur in Apulia—Volcanoes still constantly

forming—Jorullo and Isalco—Submarine Volcanoes—Sabrina and Graham’s

Island—Santorin—Number of Volcanoes—Their Distribution—Volcanoes in a

constant state of eruption—Stromboli—Fumaroles—The Lava Lakes in

Kilauea—Volcanic Paroxysms—Column of Smoke and Ashes—Detonations—

Explosion of Cones—Disastrous Effects of Showers of Ashes and Lapilli—

Mud Streams—Fish disgorged from Volcanic Caverns—Eruption of Lava—

Parasitic Cones—Phenomena attending the Flow of a Lava Stream—Baron

Papalardo—Meeting of Lava and Water—Scoriæ—Lava and Ice—Vast

Dimensions of several Lava Streams—Scenes of Desolation—Volcanoes

considered as safety-valves—Probable Causes of Volcanoes.

Volcanoes are vents which either have communicated, or still

communicate, by one or several chimney-like canals or shafts, with a

focus of subterranean fire, emitting, or having once emitted, heated

matter in a solid, semi-liquid, or gaseous state. The first eruption of

a volcano necessarily leaves a mound of scoriæ and lava, while numerous

eruptions at length raise mountains, which are frequently of an amazing

extent and height. These mountains, which are generally called

volcanoes, though in reality they are but an effect of volcanic action

situated far beneath their base, are called _extinct_ when for many

centuries they have exhibited no signs of combustion—_active_, when,

either perpetually or from time to time, eruptions or exhalations of

lava, scoriæ, or gases take place from their summits, or from vents in

their sides. Their shape is generally that of a more or less truncated

cone; but while some, like Cotopaxi or the Peak of Teneriffe, rise with

abrupt declivities in the shape of a sugar-loaf, others, like Mauna Loa

in the island of Hawaii, gradually, and almost imperceptibly, ascend

from a vast base embracing many miles in circuit.

Their heights also vary greatly. While some, like Madana in Santa Cruz,

or Djebel Teir on the coast of the Red Sea, scarcely raise their summits

a few hundred feet above the level of the ocean, others, like

Chuquibamba (21,000 feet), or Aconcagua (22,434 feet), hold a

conspicuous rank among mountains of the first class.

The summit of a volcano generally terminates in a central cavity or

crater, where the eruptive channel finds its vent. Craters are sometimes

regularly funnel-shaped, descending with slanting sides to the eruptive

mouth, but more commonly they are surrounded with high precipitous rock-

walls, while their bottom forms a plain, which is frequently completely

horizontal, and sometimes of a considerable extent. Its surface is rough

and uneven, from the mounds of volcanic sand, of scoriæ, or of hardened

lava with which it is covered, and generally exhibits a scene of

dreadful desolation, rendered still more impressive by the steam and

smoke, which, as long as the volcano continues in an active state, issue

from its crevices.

Within this plain, the eruptive orifice or mouth of the volcano is

almost universally surrounded by an elevation, composed of ejected

fragments of scoriæ thrown from the vent. Such cones are forming

constantly at Vesuvius, one being no sooner destroyed by any great

eruption, before another begins to take shape and is enlarged, till

often it reaches a height of several hundred feet.

Thus the crater of an active volcano is the scene of perpetual change—of

a continual construction and re-construction, and the sands of the sea

do not afford a more striking image of inconstancy.

The various craters are of very different dimensions. While the chief

crater of Stromboli has a diameter of only fifty feet, that of Gunong

Tenger, in Java, measures four miles from end to end; and, though the

depth of a crater rarely exceeds 1,000 or 1,500 feet, the spectator,

standing on the brink of the great crater of Popocatepetl, looks down

into a gulf of 8,000 feet.

From the colossal dimensions of the larger craters, it may well be

imagined that their aspect exhibits some of the sublimest though most

gloomy scenery in nature—the picture of old Chaos with all its horrors.

The volcano Gunong Tjerimai, in Java, which rises to the height of 9,000

feet, is covered with a dense vegetation up to the crater’s brink. On

emerging from the thicket, the wanderer suddenly stands on the verge of

an immense excavation encircled with naked rocks. He is obliged to hold

himself by the branches of trees, or to stretch himself flat upon the

ground, so as to be able to look down into the yawning gulf. The deep

and inaccessible bottom of the crater loses itself in misty obscurity,

and glimmers indistinctly through the vapours which are there slowly and

incessantly ascending from its mysterious depths. All is desolate and

silent, save when a solitary falcon, hovering over the vast chasm,

awakes with her discordant screech the echoes of the precipice. Through

a telescope may be seen, in various parts of the huge crater walls,

swarms of small swallows, which have there built their nests, flying

backwards and forwards. The eye can detect no other signs of life, the

ear distinguish no other sound.

Humboldt describes the view down the crater of the Rucu-Pichincha—a

volcano which towers above the town of Quito to a height of 15,000 feet—

as the grandest he ever beheld during all his long wanderings. Guided by

an Indian, he ascended the mountain in 1802, and after scaling, with

great difficulty and no small danger, its steep and rocky sides, he at

length looked down upon the black and dismal abyss, whence clouds of

sulphurous vapour were rising as from the gates of hell.

The descent into the crater of an active volcano is at all times a

difficult and hazardous enterprise, both from the steepness of its

encircling rock walls, and the suffocating vapours rising from its

bottom; but it is rare indeed that a traveller has either the temerity

or the good fortune to penetrate as far as the very mouth of the

eruptive channel, and to gain a glimpse of its mysterious horrors. When

M. Houel visited Mount Etna in 1769, he ventured to scale the cone of

stones and ashes which had been thrown up in the centre of the crater,

where thirty years before there was only a prodigious chasm or gulf. On

ascending this mound, which emitted smoke from every pore, the

adventurous traveller sunk about mid-leg at every step, and was in

constant terror of being swallowed up. At last, when the summit was

reached, the looseness of the soil obliged him to throw himself down

flat upon the ground, that so he might be in less danger of sinking,

while at the same time the sulphurous exhalations arising from the

funnel-shaped cavity threatened suffocation, and so irritated his lungs

as to produce a very troublesome and incessant cough. In this posture

the traveller viewed the wide unfathomable gulf in the middle of the

crater, but could discover nothing except a cloud of smoke, which issued

from a number of small apertures scattered all around. From time to time

dreadful sounds issued from the bowels of the volcano, as if the roar of

artillery were rebellowed throughout all the hollows of the mountain.

They were no doubt occasioned by the explosions of pent-up gases

striking against the sides of these immense caverns, and multiplied by

their echoes in an extraordinary manner. After the first unavoidable

impression of terror had been overcome, nothing could be more sublime

than these awful sounds, which seemed like a warning of Etna not to pry

too deeply into his secrets.

Dr. Judd, an American naturalist, who, in 1841, descended into the

crater of Kilauea, on Mauna Loa, in Hawaii, well-nigh fell a victim to

his curiosity. At that time, the smallest of the two lava pools which

boil at the bottom of that extraordinary pit appeared almost inactive,

giving out only vapours, with an occasional jet of lava at its centre.

Dr. Judd, considering the quiet favourable for dipping up some of the

liquid with an iron ladle, descended for the purpose to a narrow ledge

bordering the pool. While he was preparing to carry out his plans, his

attention was excited by a sudden sinking of its surface; the next

instant it began to rise, and then followed an explosion, throwing the

lava higher than his head. He had scarcely escaped from his dangerous

situation, the moment after, by the aid of a native, before the lava

boiled up, covered the place where he stood, and, flowing out over the

northern side, extended in a stream a mile wide to a distance of more

than a mile and a half!

In extinct volcanoes, the picture of desolation originally shown by

their craters has not seldom been changed into one of charming

loveliness. Tall forest trees cover the bottom of the Tofua crater in

Upolu, one of the Samoan group; and in the same island, a circular lake

of crystal purity, belted with a girdle of the richest green, has formed

in the depth of the Lanuto crater.

[Illustration: EXTINCT CRATER OF HALEAKALA.]

The lakes of Averno near Naples, and of Bolsena, Bracciano, and

Ronciglione, likewise fill the hollows of extinct craters, constituting

scenes of surpassing beauty, rendered still more impressive by the

remembrance of the stormy past which preceded their present epoch of

tranquillity and peace. Mr. Mallet describes, with glowing colours, the

singular beauty of

the forest scenery around the two extinct craters of Mount Vultur in

Apulia, which time has converted into two deep circular lakes.

‘I descend amongst aged trunks and overarching limbs, and pass over

masses of rounded lava-blocks and cemented lapilli. All is quietude; the

soft breeze of a quiet winter’s afternoon fans across the embosomed

water, from the early wheat-fields and the furrowed acres of the

opposite steep slopes, and brings the gentle ripple lapping amongst the

roots of the old hazels at my feet.

‘Off before me, and to my left, crowning the slope, are the grey ruins

of some ancient church or castle, and far above me to the right, nestled

against the lava crags, behind and above it, standing out white and

clear, I see the strong buttressed mass of the monastery of St. Michael.

How hard it is to realise that this noble and lovely scene, full of

every leafy beauty, was once the innermost bowl of a volcano; that every

stone around me, now glorious in colour with moss and lichen, sedum and

geranium, was once a glowing mass, vomited from out that fiery and

undiscovered abyss, which these placid waters now bury in their secret

chambers.’

The line of demarcation between active and extinct volcanoes is not

easily drawn, as eruptions have sometimes taken place after such long

intervals of repose as to warrant the belief that the vents from which

they issued had long since been completely obliterated. Thus, though

nearly six centuries have passed since the last eruption of Epomeo in

the island of Ischia, we are not entitled to suppose it extinct, since

nearly seventeen centuries elapsed between this last explosion and the

one which preceded it. Since the beginning of the fourteenth century

Vesuvius also enjoyed a long rest of nearly three hundred years. During

this time the crater got covered with grass and shrubs, oak and chestnut

trees grew around it, and some warm pools of water alone reminded the

visitor of the former condition of the mountain, when, suddenly, in

December 1631, it resumed its ancient activity, and seven streams of

lava at once burst forth from its subterranean furnaces.

While, in many volcanic districts, such as that of the Eifel on the left

bank of the Rhine, and of Auvergne, in Central France, the once active

subterranean fires have long since been extinguished, and no eruption of

lava has been recorded during the whole period of the historic ages, new

volcanoes, situated at a considerable distance from all previously

active vents, have arisen from the bowels of the earth, almost within

the memory of living man. From the era of the discovery of the New World

to the middle of the last century, the country between the mountains

Toluca and Colima, in Mexico, had remained undisturbed, and the space,

now the site of Jorullo, which is one hundred miles distant from each of

the above-mentioned volcanoes, was occupied by fertile fields of

sugarcane and indigo, and watered by two brooks. In the month of June

1759, hollow sounds of an alarming nature were heard, and earthquakes

succeeded each other for two months, until, at the end of September,

flames issued from the ground, and fragments of burning rocks were

thrown to prodigious heights. Six volcanic cones, composed of scoriæ and

fragmentary lava, were formed on the line of a chasm, which ran in the

direction of N.E. to S.W. The least of the cones was 300 feet in height,

and Jorullo, the central volcano, was elevated 1,600 feet above the

level of the plain. The ground where now, in Central America, Isalco

towers in proud eminence, was formerly the seat of an estancia or

cattle-estate. Towards the end of the year 1769, the inhabitants were

frequently disturbed by subterranean rumblings and shocks, which

constantly increased in violence, until on February 23, 1770, the earth

opened, and pouring out quantities of lava, ashes, and cinders gave

birth to a new volcanic mountain.

Besides those volcanic vents which are situated on the dry land, there

are others which, hidden beneath the surface of the sea, reveal their

existence by subaqueous eruptions. Columns of fire and smoke are seen to

rise from the discoloured and agitated waters, and sometimes new islands

are gradually piled up by the masses of scoriæ and ashes ejected from

the mouth of the submarine volcano. In this manner the island of Sabrina

rose from the bottom of the sea, near St. Michael’s in the Azores, in

the year 1811; and still more recently, in 1831, Graham’s Island was

formed in the Mediterranean, between the coast of Sicily and that

projecting part of the African coast where ancient Carthage stood.

Slight earthquake shocks preceded its appearance, then a column of water

like a water-spout, 60 feet high and 800 yards in circumference, rose

from the sea, and soon afterwards dense volumes of steam, which ascended

to the height of 1,800 feet. Then a small island, a few feet high with a

crater in its centre, ejecting volcanic matter, and immense columns of

vapour, emerged from the agitated waters, and in a fortnight swelled to

the ample proportions of a height of 200 feet, and a circumference of

three miles. But both Sabrina and Graham’s Island, being built of loose

scoriæ, were soon corroded by the waves, and their last traces have long

since disappeared under the surface of the ocean.

Near Pondicherry, in India; near Iceland, in the Atlantic Ocean; half a

degree to the south of the equator in the prolongation of a line drawn

from St. Helena to Ascension; near Juan Fernandez, &c., similar

phenomena have occurred within the last hundred years, but, probably,

nowhere on a grander scale than in the Aleutian Archipelago, where,

about thirty miles to the north of Unalaska, near the isle of Umnack, a

new island, now several thousand feet high and two or three miles in

circumference, was formed in 1796. The whole bottom of the sea between

this new creation of the volcanic powers and Umnack has been raised by

the eruptive throes which gave it birth; and where Cook freely sailed in

1778, numberless cliffs and reefs now obstruct the passage of the

mariner.

The famous subaqueous volcano which, in the year 186 before the

Christian era, began its series of historically recorded eruptions, by

raising the islet of Hiera (the ‘Sacred’) in the centre of the Bay of

Santorin, opened two new vents in 1866. Amid a tremendous roar of steam

and the shooting up of prodigious masses of rock and ashes, two islets

were formed, which ultimately rose to the height of 60 and 200 feet. The

eruption continued for many months, to the delight and wonder of the

numerous geologists who came from all sides to witness the extraordinary

spectacle. Thus, in many parts of the ocean, we see the submarine

volcanic fires laying the foundations of new islands and archipelagos,

which, after repeated eruptions following each other in the course of

ages, will probably, like Iceland, extend over a considerable space and

become the seats of civilised man.

[Illustration:

Map of the World

_Showing the Distribution of_

VOLCANOES

& the Districts visited by

EARTHQUAKES

]

As a very considerable part of the globe has never yet been

scientifically explored, it is, of course, impossible to determine the

exact number of the extinct and active volcanoes which are scattered

over its surface. Werner gives a list of 193 volcanoes, and Humboldt

mentions 407, of which 225 are still in a state of activity. The newest

computation of Dr. Fuchs, of Heidelberg,[7] increases the number to a

total of 672, of which 270 are active. Future geographical discoveries

will, no doubt, make further additions to the list, and show that at

least through a thousand different vents the subterranean fires have, at

various periods of the earth’s history, piled up their cones of scoriæ

and lava.

Footnote 7:

‘Die vulcanischen Erscheinungen der Erde.’ Liepzig, 1865.

The volcanoes are very unequally distributed over the surface of the

globe, for, while in some parts they are thickly clustered together in

groups or rows, we find in other parts vast areas of land without the

least sign of volcanic action.

An almost uninterrupted range of volcanoes extends in a sinuous line

from the Gulf of Bengal, through the East Indian Archipelago, the

Moluccas, the Philippines, Formosa, Japan, and the Kuriles, to

Kamtschatka. This desolate peninsula is particularly remarkable for the

energy of its subterranean fires, as Ermann mentions no less than

twenty-one active volcanoes, ranged in two parallel lines throughout its

whole length, and separated from each other by a central range of

mountains, containing a large and unknown number of extinct craters.

In Java, where more than thirty volcanoes are more or less active, the

furnaces of the subterranean world are still more concentrated and

dreadful.

The immense mountain-chains which run parallel to the western coasts of

America are likewise crowned with numerous volcanic peaks. Chili alone

has fourteen active volcanoes, Bolivia and Peru three, Quito eleven. In

Central America we find twenty-one volcanoes, which are chiefly grouped

near the Lake of Nicaragua, and to the west of the town of Guatemala.

The peninsula of Aljaska, and the chain of the Aleütes, possess no less

than thirty-six volcanos, scattered over a line about 700 miles long;

and thus we find the eastern, western, and northern boundaries of the

Pacific encircled with a girdle of volcanic vents, while the

subterranean fires have left the western shores of the Atlantic

comparatively undisturbed.

With the exception of Iceland, which is famous for the widely

devastating eruptions of its burning mountains, the volcanic energies of

Europe are at present limited to the submarine crater of Santorin, and

to the small area of Etna, Vesuvius, and the Lipari Islands. But,

situated in the centre of the ancient seats of civilisation, and for so

many centuries the object of the naturalist’s researches, of the

traveller’s curiosity, and of the poet’s song, they surpass in renown

all other volcanic regions in the world. Most other volcanoes vent their

fury over lands either so wild or so remote that the history of their

eruptions almost sounds like a legend from another planet; but thousands

of us have visited Etna and Vesuvius, and the explosion of their rage

menaces towns and countries which classical remembrances have almost

invested with the interest of home.

Some volcanoes are in a continual state of eruption. Isalco, born, as we

have seen, in 1770, has remained ever since so active as to deserve the

name of the Faro (lighthouse) of San Salvador. Its explosions occur

regularly, at intervals of from ten to twenty minutes, and throw up a

dense smoke and clouds of ashes and stones. These, as they fall, add to

the height and bulk of the cone, which is now about 2,500 feet high. For

more than two thousand years, the fires of Stromboli have never been

extinct, nor has it ever failed to be a beacon to the mariner while

sailing after nightfall through the Tyrrhenian Sea. Mr. Poulett Scrope,

who visited Stromboli in 1820, and looked down from the edge of the

crater into the mouth of the volcano, some 300 feet beneath him, found

the phenomena precisely such as Spallanzani described them in 1788. ‘Two

rude openings show themselves among the black chaotic rocks of scoriform

lava which form the floor of the crater. One, is to appearance, empty,

but from it there proceeds, at intervals of a few minutes, a rush of

vapour, with a roaring sound, like that of a smelting furnace when the

door is opened, but infinitely louder. It lasts about a minute. Within

the other aperture, which is perhaps twenty feet in diameter, and but a

few yards distant, may be distinctly perceived a body of molten matter,

having a vivid glow even by day, approaching to that of white heat,

which rises and falls at intervals of from ten to fifteen minutes. Each

time that it reaches in its rise the lip of the orifice, it opens at the

centre, like a great bubble bursting, and discharges upwards an

explosive volume of dense vapour, with a shower of fragments of

incandescent lava and ragged scoriæ, which rise to a height of several

hundred feet above the lip of the crater.’

The volcanoes of Masaya, near the lake of the same name in Nicaragua; of

Sioa, in the Moluccas; and of Tofua, in the Friendly Islands, are also,

like Stromboli, in a state of permanent eruption. But far more commonly

the volcanoes burst forth only from time to time in violent paroxysms,

separated from each other by longer phases of moderate activity, during

which their phenomena are confined to the exhalation of vapours and

gases, sometimes also to the ejection of scoriæ or ashes; to the

oscillations of lava rising or subsiding in the shaft of the crater, to

the gentle outflow of small streams of lava from its eruptive cone, and

to slight commotions of its border. A continual or periodical exhalation

of steam and gases from the shaft of the crater or from chasms and

fissures in its bottom, is the commonest phenomenon shown by an active

volcano while in a state of tranquillity. Aqueous vapours compose the

chief part of these exhalations, and along with other volatile

substances, such as sulphuretted hydrogen, sulphurous acid, muriatic

acid, and carbonic acid, form the steam-jets or _fumaroles_, which

escape with a hissing or roaring noise from all the crevices and chasms

of the crater, and, uniting as they ascend in a single vapour-cloud,

ultimately compose the lofty column of steam which forms so conspicuous

a feature in the picturesque beauty of Etna or Vesuvius. High on the

summit of Mauna Loa, where all vegetation has long since ceased, the

warm steam of the fumaroles gives rise to a splendid growth of ferns in

crevices sheltered from the wind; and on the island of Pantellaria, the

shepherds, by laying brushwood before the fumaroles, condense the steam,

and thus procure a supply of water for their goats.

The gentle fluctuations of lava in a crater while in a state of moderate

activity are nowhere exhibited on a grander scale than in the pit of

Kilauea on Mauna Loa. The mountain rises so gradually as almost to

resemble a plain, and the crater appears like a vast gulf excavated in

its flanks. The traveller perceives his approach to it by a few small

clouds of steam, rising from fissures not far from his path. While

gazing for a second indication, he stands unexpectedly upon the brink of

the pit. A vast amphitheatre seven miles and a half in circuit has

opened to view. Beneath a gray rocky precipice of 650 feet, a narrow

plain of hardened lava extends, like a vast gallery, around the whole

interior. Within this gallery, below another similar precipice of 340

feet, lies the bottom, a wide plain of bare rock more than two miles in

length. Here all is black monotonous desolation, excepting certain spots

of a blood-red colour, which appear to be in constant yet gentle

agitation.

When Professor Dana visited Kilauea (December 1840), he was surprised at

the stillness of the scene. The incessant motion in the blood-red pools

was like that of a cauldron in constant ebullition. The lava in each

boiled with such activity as to cause a rapid play of jets over its

surface. One pool, the largest of the three then in action, was

afterwards ascertained by survey to measure 1,500 feet in one diameter

and 1,000 in another; and this whole area was boiling, as seemed from

above, with nearly the mobility of water. Still all went on quietly. Not

a whisper was heard from the fires below. White vapours rose in fleecy

wreaths from the pools and numerous fissures, and above the large lake

they collected into a broad canopy of clouds, not unlike the snowy heaps

or cumuli that lie near the horizon on a clear day, though their

fanciful shapes changed more rapidly.

On descending afterwards to the black ledge or gallery at the verge of

the lower pit, a half-smothered gurgling sound was all that could be

heard from the pools of lava. Occasionally, there was a report like that

of musketry, which died away, and left the same murmuring sound, the

stifled mutterings of a boiling fluid.

Such was the scene by day—awful, melancholy, dismal—but at night it

assumed a character of indescribable sublimity. The large cauldron, in

place of its bloody glare, now glowed with intense brilliancy, and the

surface sparkled with shifting points of dazzling light, occasioned by

the jets in constant play. The broad canopy of clouds above the pit,

which seemed to rest on a column of wreaths and curling heaps of lighted

vapour, and the amphitheatre of rocks around the lower depths, were

brightly illuminated from the boiling lavas, while a lurid red tinged

the distant parts of the inclosing walls and threw their cavernous

recesses into deeper shades of darkness. Over this scene of restless

fires and fiery vapours, the heavens by contrast seemed unnaturally

black, with only here and there a star, like a dim point of light.

A paroxysmal eruption is generally announced by the intensification of

the phenomena above described. Slight earthquakes are felt in the

neighbourhood of the volcano, and follow each other in more rapid

succession and with greater violence as the catastrophe draws near. A

deep noise like the rolling of thunder, or like the roar of distant

artillery, is heard under the ground; the white steam from the crater

ascends in denser clouds, which soon acquire a darker tinge; and now the

bottom of the crater suddenly bursts with a terrific crash, and with the

rapidity of lightning, an immense column of black smoke shoots up into

the air, and, expanding at its upper end into a broad horizontal canopy,

assumes a shape which has been compared with that of the Italian pine,

the graceful tree of the South. As the column of smoke spreads over the

sky, it obscures the light of the sun and changes day into night. Along

with the smoke, showers of glowing lava are cast high up into the air,

and, rising like rockets, either fall back into the crater or rattle

down the declivity of the cone.

At night the scene assumes a character of matchless grandeur, when the

column of smoke—or, more properly speaking, of scoriæ, vapour, and

impalpable dust—is illuminated by the vivid light of the lava glowing in

the crater beneath. It then appears as an immense pillar of fire, rising

with steady majesty in the midst of the uproar of all the elements, and

ever and anon traversed by flashes of still greater brilliancy from the

masses of liquid lava hurled forth by the volcano.

The detonations which accompany an eruption are sometimes heard as

single crashes, at others as a rolling thunder or as a continuous

roaring. They are frequently audible at an astonishing distance, over

areas of many thousand square miles, and with such violence that they

may be supposed to proceed from the immediate neighbourhood. Thus,

during the eruption of Cosiguina in Nicaragua, which took place in the

year 1834, the detonations were heard as loud as a thunderstorm in the

neighbourhood of Kingston in Jamaica, and even at Santa Fé de Bogota,

which is a thousand miles distant from the volcano. With the increase of

steam generated during an eruption, the quantity of ejected scoriæ

likewise increases in an astonishing manner, so that the volcano’s mouth

resembles a constantly discharging mine of the most gigantic dimensions.

The stones and ashes projected during a volcanic eruption vary

considerably in size, from blocks twelve or fifteen feet in diameter to

the finest dust. Both their immense quantity, and the force with which

they are hurled into the air, show the utter insignificance of the

strength displayed by the most formidable engines invented by man when

compared with elementary power. Huge blocks are shot forth, as from the

cannon’s mouth, to a perpendicular elevation of 6,000 feet, and La

Condamine relates that in 1533 Cotopaxi hurled stones of eight feet in

diameter in an oblique direction to the distance of seven miles. The

lighter scoriæ, carried far away by the winds, not seldom bury whole

provinces under a deluge of sand and ashes; and their disastrous

effects, spreading over an immense area, are frequently greater than

those of the lava-streams, whose destructive power is necessarily

confined to a narrower space. To cite but a few examples, the rain of

sand and ashes which in 1812 menaced the Island of St. Vincent with the

fate of Pompeii soon buried every trace of vegetation, and the

affrighted planters and negroes fled to the town. But here also the

black sand, along with many larger stones, fell rattling like hail upon

the roofs of the houses, while at the same time a tremendous

subterranean thunder increased the horrors of the scene. Even Barbadoes,

though eighty miles from St. Vincent’s, was covered with ashes. A black

cloud, approaching from the sea, brought with it such pitchy darkness

that in the rooms it was impossible to distinguish the windows, and a

white pocket-handkerchief could not be seen at a distance of five

inches.

The fall of ashes caused in April 1815 by the eruption of the Temboro,

in Sumbawa, not only devastated the greater part of the island, but

extended in a westerly direction to Java, and to the north, as far as

Celebes, with such an intensity that it became perfectly dark at noon.

The roofs of houses at the distance of forty miles were broken in by the

weight of the ashes that fell upon them. To the west of Sumatra the

surface of the sea was covered two feet deep with a layer of floating

pumice or scoriæ, through which ships with difficulty forced their way.

By the terrific eruption of Cosiguina in the Gulf of Fonseca, in Central

America, in 1835, all the ground within a radius of twenty-five miles

was loaded with scoriæ and ashes to the depth of ten feet and upwards,

while the lightest and finest ash was carried by the winds to places

more than 700 miles distant. Eight leagues to the southward of the

crater the ashes covered the ground to the depth of three yards and a

half, destroying the woods and dwellings. Thousands of cattle perished,

their bodies being in many instances one mass of scorched flesh. Deer

and other wild animals sought the towns for protection; birds and beasts

were found suffocated in the ashes, and the neighbouring streams were

strewed with dead fish.

When we consider the amazing quantity of stones and ashes ejected in

these and similar instances by volcanic power, we cannot wonder that

considerable mountains have frequently been piled up by one single

eruption. Thus in the Bay of Baiæ near Naples, Monte Nuovo, a hill 440

feet high, and with a base of more than a mile and a half in

circumference, formed, in less than twelve hours, on September 29, 1538;

and a few days gave birth to Monte Minardo, near Bronte, on the slopes

of Etna, which rises to the still more considerable height of 700 feet.

It would be curious to calculate how many thousands of workmen, and what

length of time, man would need to raise mounds like these, produced by

an almost instantaneous effort of nature.

In other cases the expansive power of the elastic vapours, which cast up

these prodigious masses from the bowels of the earth, is such as to blow

to pieces the volcanic cone through which it seeks its vent.

In Quito there is an ancient tradition that Capac Urcu, which means ‘the

chief,’ was once the highest volcano near the equator, being higher than

Chimborazo, but at the beginning of the fifteenth century a prodigious

eruption took place which broke it down. The fragments of trachyte, says

Mr. Boussingault, which once formed the conical summit of this

celebrated mountain, are at this day spread over the plain. On August

11, 1772, the Pepandajan, in Java, formerly one of the highest mountains

of the island, broke out in eruption; the inhabitants of the country

around prepared for flight, but, before they could escape, the greater

part of its summit was shivered to pieces and covered the neighbourhood

with its ruins, so that in the upper part of the Gurat valley forty

villages were completely buried. During the dreadful eruption of 1815,

the Temboro, in Sumbawa, is said to have lost at least one-third of its

height from the explosion of its summit, and similar instances are

mentioned as having occurred among the volcanoes of Japan.

In the year 1638 a colossal cone called the Peak, in the Isle of Timor,

one of the Moluccas, was entirely destroyed by a paroxysmal explosion.

The whole mountain, which was before this continually active, and so

high that its light was visible, it is said, three hundred miles off,

was blown up and replaced by a concavity now containing a lake.

Again, according to M. Moreau de Jonnes, in 1718, on March 6–7, at St.

Vincent’s, one of the Leeward Isles, the shock of a terrific earthquake

was felt, and clouds of ashes were driven into the air, with violent

detonations, from a mountain situated at the eastern end of the island.

When the eruption had ceased, it was found that the whole mountain had

disappeared like the baseless fabric of a dream.

The disastrous effects of the showers of sand, pumice, and lapilli

ejected by a volcanic eruption are increased by the transporting power

of water. The aqueous vapours which are evolved so copiously from

volcanic craters during eruptions, and often for a long time

subsequently to the discharge of scoriæ and lava, are condensed as they

ascend in the cold atmosphere surrounding the high volcanic peak; and

the clouds thus formed, being in a state of high electrical tension,

give rise to terrific thunderstorms. The lightning flashes in all

directions from the black canopy overhanging the mountain, the

perpetually rolling thunder adds its loud voice to the dreadful roar of

the labouring volcano, while torrents of rain, sweeping along the light

dust and scoriæ which they carry down with them from the air, or meet

with on their way, produce currents of mud, often more dreaded than

streams of lava, from the far greater velocity with which they move.

It not seldom happens that the eruptions of volcanoes rising above the

limits of perpetual snow are preceded or accompanied by the rapid

dissolution of the ice which clothes their summits or their sides, owing

to the high temperature imparted to the whole mass of the mountain by

the vast conflict raging within. Thus in January 1803 one single night

sufficed to dissolve or sweep away the enormous bed of snow which in

times of rest covers the steep cone of Cotopaxi (18,858 feet high), so

that on the following morning the dark mountain, divested of its

brilliant robe, gave warning to the affrighted neighbourhood of the

terrific scenes that were about to follow. The volcanoes of Iceland,

which mostly rise in the midst of vast fields of perpetual ice,

frequently exhibit this phenomenon. On October 17, 1758, the eruptive

labouring of Kötlingia gave birth to three enormous torrents, which

carried along with them such masses of glacier fragments, sand, and

stones as to cover a space fifty miles long and twenty-five miles broad.

Blocks of ice as large as houses, and partly bearing immense pieces of

stone on their backs, were hurried along by the floods; and soon after

the eruption took place with a terrific noise.

A very singular phenomenon sometimes occurs in the gigantic volcanoes of

the Andes. By the infiltration of water into the crevices of the

trachytic rock of which they are composed, the caverns situated at their

declivities or at their foot are gradually changed into subterranean

lakes or ponds, which frequently communicate by narrow apertures with

the Alpine brooks of the highlands of Quito. The fish from these brooks

live and multiply in these subterranean reservoirs thus formed, and when

the earthquakes which precede every eruption of the Andes chain shake

the whole mass of the volcano, the caverns suddenly open and discharge

enormous quantities of water, mud, and small fish.

When in the night between the 19th and 20th of June 1698, the summit of

Carguairazo (18,000 feet high) was blown up, so that of the whole

crater-rim but two enormous peaks remained, the inundated fields were

covered, over a surface of nearly fifty square miles, with fluid tuff

and clay-mud enveloping thousands of dead fish. Seven years before, the

malignant fever which prevailed in the mountain-town of Ibarra to the

north of Quito was attributed to the effluvia arising from the putrid

fish ejected by the volcano of Imbaburu.

Amidst all these terrible phenomena—the dreadful noise, the quaking of

the earth, the ejection of stones and ashes—which, often continuing for

weeks or months, shake the deepest foundations of the volcano, fiery

streams of liquid lava gush forth sooner or later as from a vase that is

boiling over. Their appearance generally indicates the crisis of the

subterranean revolution, for the rage of the elements, which until then

had been constantly increasing, diminishes as soon as the torrent has

found an outlet. The lava rarely issues from the summit crater of the

mountain; much more frequently it flows from a lateral rent in the

volcano’s side, which, weakened and dislocated in its texture by

repeated shocks, at length gives way to the immense pressure of the lava

column boiling within. From the vast size of these eruptive rents, we

may form some idea of the gigantic power of the forces which give them

birth.

Thus during the great eruption of Etna in 1669, the south-east flank of

the mountain was split open by an enormous rent twelve miles long, at

the bottom of which incandescent lava was seen. The extreme length of

the fissure which gave lateral issue to the lava of Kilauea in 1840 was

twenty-five miles, as could distinctly be traced through the disturbance

of the surface rocks above; and in the terrific eruption of Skaptar

Jökul, which devastated the west coast of Iceland in 1783, lava gushed

forth from several vents along a fissure of not less than 100 miles in

length. In some cases the whole mass of the volcano has been cleft in

two. Vesuvius was thus rent in October 1822 by an enormous fissure

broken across its cone in a direction N.W.—S.E.

Here and there along the line of such a rent, cones of eruption are

thrown up in succession at points where the gaseous matter obtains the

freest access to the surface, and has power to force up lava and scoriæ.

Few indeed, if any, of the greater volcanic mountains are unattended by

such minor elevations, clustering about its sides like the satellites of

a planet. Professor Dana found Mauna Loa covered with numerous parasitic

cones, and Mr. Darwin counted several thousands on one of the Gallapagos

Islands. On the flanks of Etna, according to Professor Sartorius von

Waltershausen, more than 700 of them are to be seen, almost all

possessing craters, and each marking the source of a current of lava.

Though they appear but trifling irregularities when viewed from a

distance as subordinate parts of so imposing and colossal a mountain,

many of them would nevertheless be deemed hills of considerable height

in almost any other region. The double hill near Nicolosi, called Monte

Rossi, formed in 1669, is 450 feet high and two miles in circumference

at its base; and Monte Minardo, near Bronte, on the east of the great

volcano, is upwards of 700 feet in height.[8]

Footnote 8:

See p. 67.

‘On looking down from the lower borders of the desert region of Etna,’

says Sir Charles Lyell, ‘these minor volcanoes, which are most abundant

in the woody region, present us with one of the most delightful and

characteristic scenes in Europe. They afford every variety of height and

size, and are arranged in beautiful and picturesque groups. However

uniform they may appear when seen from the sea, or the plains below,

nothing can be more diversified than their shape when we look from above

into their craters, one side of which, as we have seen, is generally

broken down. There are indeed, few objects in nature more picturesque

than a wooded volcanic crater. The cones situated in the higher parts of

the forest zone are chiefly clothed with lofty pines, while those at a

lower elevation are adorned with chestnuts, oaks, and beech-trees.’

As the point where a lava-current finds a vent is often situated at a

considerable distance below the surface of the liquid column in the

internal chimney of the volcano, the pressure from above not seldom

causes the lava to spout forth in a jet, until its level in the crater

shaft has been reduced to that of the newly-formed orifice. Thus, when

Vesuvius was rent by the dreadful paroxysmal eruption of 1794, the lava

was seen to shoot up in magnificent fountains as it issued from the

openings along the fissure.

Further on, the lava flows down the mountain’s side according to the

same laws which regulate the movements of any other stream, whether of

water, mud, or ice: more rapidly down an abrupt declivity, slower where

the slope is more gradual; now accumulating in narrow ravines, then

spreading out in plains; sometimes rushing in fiery cascades down

precipices, and, where insurmountable obstacles oppose its progress, not

seldom breaking off into several branches, each of which pursues its

independent course.

At the point where it issues, the lava flows in perfect solution, but,

as its surface rapidly cools when exposed to the air, it soon gets

covered with scoriæ, which are dashed over each other in wild confusion,

by successive floods of liquid stone, so as to resemble a stormy sea

covered with ice-blocks. But the liquefied stone not only hardens on its

external surface; it also becomes solid below, where it touches the

colder soil, so that the fluid lava literally moves along in a crust of

scoriæ, which lengthens in the same proportion as the stream advances.

The movements of the lava-current are of course considerably retarded by

the formation of scoriæ, so that, unless where a greater inclination of

the soil gives it a new impulse, it flows slower and slower. Thus the

lava-stream which was ejected by Etna during the great eruption of 1669,

performed the first thirteen Italian miles of its course in twenty days,

or at the average rate of 162 feet per hour, but required no less than

twenty-three days for the last two miles. While moving on, its surface

was in general a mass of solid rock; and its mode of advancing, as is

usual with lava streams, was by the occasional fissuring of the solid

walls. Yet, in spite of the tardiness of its progress, the inhabitants

of Catania watched its advance with dismay, and rushed into the churches

to invoke the aid of the Madonna and the Saints. One citizen only, a

certain Baron Papalardo, relied more upon his own efforts than upon

supernatural assistance, and set out with a party of fifty men, dressed

in skins to protect them from the heat, and armed with iron crows and

hooks for the purpose of breaking open one of the solid walls of scoriæ

that flanked the liquid current, so as to divert it from the menaced

city. A passage was thus opened for a rivulet of melted matter, which

flowed in the direction of Paterno; but the inhabitants of that town

being alarmed for their safety, took up arms against Papalardo, whose

fifty workmen would hardly have been able to cope with the powers of

nature. Thus, slowly but irresistibly, the lava advanced up to the walls

of Catania, which, being formed of huge Cyclopean blocks, and no less

than sixty feet high, at first stemmed the fiery stream. But the glowing

floods, pressing against the rampart, rose higher and higher, and

finally reaching its summit, rushed over it in fiery cataracts, and

destroying part of the town, at length disgorged themselves into the

sea, where they formed a not inconsiderable promontory.

A truly gigantic conflict might naturally be expected from the meeting

of two such powerful and hostile bodies as fire and water. This,

however, is by no means the case, for as soon as the lava enters the

sea, the rapid evaporation of the water that comes into immediate

contact with it accelerates the cooling of the surface and thickens the

hard external crust to such a degree that very soon all communication is

cut off between the water and the fiery mass. While the lava continues

to advance from the land, the crust of scoriæ is prolonged in the same

proportion, and should it be rent here and there, steam is at once

developed with such violence as to prevent all further access of the

water into the interior of the fissures. Thus, Breislak informs us that,

in 1794, the eruption of a lava-stream into the Bay of Naples, near

Torre del Greco, took place with the greatest tranquillity, so that he

himself was able to observe the advancing of the lava into the sea while

seated in a boat immediately near it, without being disturbed by

explosions or any other violent phenomenon.

As the crust of scoriæ is so bad a conductor of heat, it occasions a

very slow cooling and hardening in the interior of the lava-stream,

forming as it were a vessel in which the liquid fire can be retained and

preserved for a long time. When Elie de Beaumont visited the lava-stream

of Etna, nearly two years after its eruption in 1832, its interior was

still so warm that he could not hold his finger in the hot steam issuing

from its crevices. It has also been proved, on trustworthy evidence,

that after twenty-five and thirty years, many lava-streams of Etna still

continued to emit heat and steam; and after twenty-one years it was

possible to light a cigar in the crevices of the lava that issued from

Jorullo in 1759.

Another extremely curious effect of the scoriæ being such bad conductors

of heat is, that masses of snow will remain unmelted, though a lava-

stream rolls over them. Thus, in 1787, the lava of Etna flowed over a

large deposit of snow, which, however, was by no means fully liquefied,

but remained for the greatest part entire, and gradually changed into a

granular and solid mass of ice. This was traced in 1828, by the

geologist Gemellaro, for a distance of several hundred feet under the

lava, and most likely still reposes under it as in an ice-cellar. The

cliffs which form the vast crater-ring of the Isle of Deception, in the

extreme Southern Atlantic, are likewise composed of alternate layers of

ice and lava. Probably in both these cases the ice-beds had been covered

before the lava flowed over them, by a rain of scoriæ and volcanic sand,

which is so well known among the shepherds in the higher regions of Etna

as a bad conductor of caloric, that, to obtain a supply of water for

their herds during the summer, they cover some snow a few inches deep

with volcanic sand, which entirely prevents the penetration of solar

heat.

Most of the recent lava-streams evolve from all their fissures and rents

a quantity of vapour, so as to be dotted with innumerable fumaroles, and

to exhibit, as they flow along, a smoking surface by day and a luminous

one by night. At first these fumaroles are so impetuous that they

frequently puff up the lava-crust around their orifices into little

cones or hillocks, consisting of blocks of scoriæ irregularly piled up

over each other, and from whose summit the vapours continue to ascend.

As the mass cools, they are naturally lessened in numbers and in power;

but in 1803 Humboldt still saw fumaroles from twenty to thirty feet

high, rising from the small cones which covered by thousands the great

lava-stream of Jorullo of the year 1759.

The vast dimensions of single lava-streams give proof of the enormous

powers which forced them out of the bowels of the earth. The lava-stream

of Vesuvius which destroyed Torre del Greco in 1794, is 17,500 French

feet long, and when it reached the town was more than 2,000 feet wide

and forty feet deep. While this mighty mass of molten stone, the volume

of which has been reckoned at about 457 millions of cubic feet, was

descending towards the sea, another stream, whose mass is computed at

about one-half of that of the former, was flowing in the direction of

Mauro. This single eruption has therefore furnished more than 685

millions of cubic feet of lava, equal to a cube of 882 feet, in which at

least a dozen of the largest churches, palaces, and pyramids on earth

might conveniently find room. If to the solid lava we add the

astonishing quantities of scoriæ, sand, and ashes thrown out by this

same eruption, we may form some idea of the masses of matter which were

in this one instance ejected from the interior of the earth.

The volume of the lava-stream which flowed from the volcano of the Isle

of Bourbon in the year 1787 is estimated at 2,526 millions of cubic

feet; but even this astonishing ejection of molten stone is surpassed by

that which took place during the eruption of Skaptar Jökull[9] in 1783,

when the lava rolled on to a length of fifty miles, and, on reaching the

plain, expanded into broad lakes, twelve and fifteen miles in diameter

and a hundred feet deep.

Footnote 9:

A detailed account of this eruption, one of the most dreadful on

record, is given in ‘The Polar World,’ chap. vi. p. 81.

In the great eruption of Mauna Loa, which commenced on the 30th of May

1840, the lava began to flow from a small pit-crater called Avare, about

six miles from Kilauea. The light was seen at a distance, but, as there

was no population in that direction, it was supposed to proceed from a

jungle on fire. The next day another outbreak was perceived farther

towards the coast, and general alarm prevailed among the natives, now

aware of the impending catastrophe. Other openings followed, and by

Monday the 1st of June the large flow had begun, which formed a

continuous stream to the sea, which it reached on the 3rd. This flood

issued from several fissures along its whole course, instead of being an

overflow of lava from a single opening; it started from an elevation of

1,244 feet, as determined by Captain Wilkes, at a point twenty-two miles

distant from the first outbreak, and twelve from the shore. The scene of

the flowing lava, as we are told by those who saw it, was indescribably

magnificent. As it rolled along it swept away forests in its course, at

times parting and inclosing islets of earth and shrubbery, and at other

times undermining and bearing along masses of rock and vegetation on its

surface. Finally, it plunged into the sea with loud detonations, and for

three weeks continued to disgorge itself with little abatement.

The light which it emitted converted night into day over all eastern

Hawaii. It was distinctly visible for more than one hundred miles at

sea, and at the distance of forty miles fine print could be read at

midnight. As previous to the eruption, the whole vast pit of Kilauea had

been filled to the brim with the lava, which, bursting through the

flanks of the mountain, thus found a vent towards the sea, we have some

means of estimating the volume of the ejected masses in the actual cubic

contents of the emptied pit. The area of the lower pit, as determined by

the surveys of the American Exploring Expedition, is equal to 38,500,000

square feet. Multiplying this by 400 feet, the depth of the pit after

the eruption, we have 15,400,000,000 cubic feet for the solid contents

of the space occupied by lava before the eruption, and therefore the

actual amount of the material which flowed from Kilauea. This is

equivalent to a triangular range 800 feet high, two miles long, and over

a mile wide at base!

Though generally symptoms of violent disturbance, such as shakings of

the earth and loud thundering noises, precede the eruption of lava, yet

this is not always the case. Thus the craters of Mount Kea have

frequently disgorged their masses of molten stone without such

accompanying phenomena. In 1843, when the volcano poured out a flood of

lava, reaching for twenty-five miles down its side, all took place so

quietly that persons at the foot of the mountain were unaware of it,

except from the glare of light after the action had begun. Through its

progress no sounds were heard below, nor did it cause any perceptible

vibrations, except in the region of the outbreak, and there none of much

violence.

The lava sometimes cools down with a smooth, solid, undulating surface,

marked with rope-like lines and concentric folds, such as are seen on

any densely viscid liquid if drawn out as it hardens; but much more

frequently it appears as if shattered to a chaos of ruins. The fragments

vary from one to hundreds of cubic feet, or from a half-bushel measure

to a house of moderate size. They are of all shapes, often in angular

blocks, and sometimes in slabs, and are horribly rough, having deep

recesses everywhere among them. The traveller shudders as his path leads

him over a lava-field, thus bristling with myriads of spikes, where the

least false step would precipitate him into the deep cavities, among the

jagged surfaces and edges. This scene of horrid confusion often extends

for miles in every direction, and, viewed from its central part, the

whole horizon around is one wide waste of gray and black desolation,

beyond the power of words to describe.

The breaking up of a lava-field into chaotic masses evidently proceeds

from a temporary cessation, either complete or partial, and a subsequent

flow of a stream of lava. The surface cools and hardens as soon as the

stream slackens; afterwards there is another heaving of the lava, and an

onward move, owing to a succeeding ejection or the removing of an

obstacle, and the motion breaks up the hardened crust, piling the masses

together, either in slabs or huge angular fragments, according to the

thickness to which the crust had cooled. If the motion of a lava-stream

be quite slow, the cooling of the front of it may cause its cessation,

thus damming it up and holding it back, till the pressure from gradual

accumulation behind sweeps away the barrier. It then flows on again,

carrying on its surface masses of the hardened crust—some, it may be, to

sink and melt again, but the larger portion to remain as a field of

clinkers. The breaking-up of the ice of some streams in spring gives

some idea of the manner in which the hardened masses of a lava-field are

piled up as it moves along; but to form a just idea of the greatness of

the effect, the mind must bring before it a stream, not of the scanty

limits of most rivers, but one, not unfrequently, of several miles in

breadth: besides, in place of slabs of pure and clear ice, there should

be substituted shaggy heaps of black scoriæ, and a depth or thickness of

many yards in place of a few inches.

Where volcanic mud-streams have flooded the land, or a rain of ashes and

light scoriæ has descended upon the soil, its fertility may soon be

restored under the influence of a sunny sky; but as far as the lava

reaches, a stony wilderness often remains for ages, particularly in the

colder regions of the earth. Thus, though many of the lava-fields of

Iceland have existed long before the first Scandinavian colonists

settled in the land, their surface is generally as naked as when they

first issued from the volcano; and where signs of vegetation may be seen

among their fragments, the eye finds nothing to relieve the horrid

monotony of the scene but spare patches of lichen and mosses, or here

and there some dwarf herb or shrub that hardly ventures to peep forth

from the crevice in which it has found a shelter. But in a milder

climate, such as that of Italy, and still more rapidly in the torrid

zone, the horrid nakedness of a lava-field undergoes a more rapid

transformation, provided a sufficient moisture favours the growth of

plants. The rains promote the decomposition of the lava, and a rank

vegetation succeeds, which in its turn assists the work of

decomposition, and thus hastens the accumulation of soil. Ferns and

grasses spring up in the nooks and crevices, and finally the vine or the

taro flourish luxuriantly, for nothing can exceed the fertility of a

disintegrated lava-field.

Volcanoes have frequently been considered as safety-valves, which, by

affording a vent to subterranean vapours, preserve the neighbouring

regions from the far more disastrous and wide-spreading effects of

earthquakes; and facts are not wanting which seem to justify this

opinion. After the soil had trembled for a long time throughout the

whole of Syria, in the Cyclades, and in Eubœa, the shocks suddenly

ceased when, in the plains near Chalcis, a stream of ‘_glowing mud_’

(lava from a crevice) issued from the bowels of the earth. Strabo, who

relates this incident, adds that ‘since the craters of Etna have been

opened, through which fire ascends, the land on the sea-coast is less

subject to earthquakes than at the time when all vents on the surface

were stopped up.’

Before the earthquake which destroyed the town of Riobamba, the smoke of

the volcano of Pasto, which is 200 miles distant, disappeared. The

Neapolitans and Sicilians consider the eruptions of Vesuvius and Etna,

or even a more lively activity of these volcanoes, as a certain

preservative against devastating earthquakes, and we meet with the same

belief among the inhabitants of Quito and Peru. But in many cases this

fancied security has proved to be delusive, as very violent earthquakes

have not seldom been found to accompany volcanic eruptions. The great

Chilian earthquake of 1835 coincided with an eruption of Antuco; and the

shocks which agitated all Kamtschatka and the long chain of the Kurilian

Islands, in 1737, occurred simultaneously with an eruption of

Klîutschewskaja Skopa.

Professor Dana doubts whether action so deep-seated as that of the

earthquake must be can often find relief in the narrow channels of a

volcano miles in length. He points out the example of Mauna Loa, where

lavas are frequently poured out from the summit crater, at an elevation

of more than 10,000 feet above Kilauea, so that the latter,

notwithstanding its extent, the size of its great lakes of lava, and the

freedom of the incessant ebullition, is not a safety-valve that can

protect even its own immediate neighbourhood.

In his opinion volcanoes might more fitly be called indexes of danger.

They point out those portions of the globe which are most subject to

earthquakes, and are results of the same causes that render a country

liable to such convulsions.

The phenomena attending an eruption can leave no doubt that below every

active volcano a large subterranean cavity must exist in which melted

lava accumulates. The partisans of the theory which supposes the earth

to consist of a central fluid mass with a solid shell resting upon it,

attribute the formation of volcanoes to rents or fissures in this crust

through which the lava is cast forth; but the local development of heat

by chemical action, or some other unknown cause, is quite sufficient to

account for the existence of fiery lakes imbedded in a solid mass, and

which, though insignificant when compared with the surface of the globe,

may still be large enough to produce volcanic phenomena on the grandest

scale.

The cause of the reaction of such a reservoir against the surface of the

earth must in all probability be sought for in the expansive force of

steam; for when water, penetrating through crevices or porous strata,

comes in contact with the heated subterranean mass, it is evident that

the steam thus generated must press upon the lava, and, when formed in

sufficient quantity, ultimately forces it up the duct of the volcano. In

other cases, we may suppose a continuous column of lava mixed with

liquid water raised to a red-hot, or white-hot, temperature under the

influence of pressure. A disturbance of equilibrium may first bring on

an eruption near the surface, by the expansion and conversion into gas

of the entangled water, so as to lessen pressure. More and more steam

would then be liberated, bringing up with it jets of liquid rock, and

ultimately ejecting a continuous stream of lava. Its force being spent,

a period of rest succeeds, until the conditions for a new outburst

(accumulation of steam and melted rock) are obtained, and another cycle

of similar changes is renewed. The important part which water plays in

volcanic action is moreover sufficiently proved by the enormous quantity

of steam which is poured forth during every eruption, or is constantly

escaping in the fumaroles of a crater. The various gases (carbonic,

muriatic, sulphurous) which are likewise exhaled by volcanoes may also

have been rendered liquid by pressure at great depths, and may assist

the action of water in causing eruptive outbursts. The great number of

active volcanoes on sea-coasts and in islands likewise points to the

agency of water in volcanic operations; and in the few cases where

eruptive cones are situated far inland, their situation on the borders

of a lake, or their cavernous and porous structure, accounts for the

absorption of a quantity of atmospheric water, sufficient for the

production of volcanic phenomena.

[Illustration: ERUPTION OF VESUVIUS, BAY OF NAPLES.]

CHAPTER VII.

DESTRUCTION OF HERCULANEUM AND POMPEII.

State of Vesuvius before the eruption in the year 79 A.C.—Spartacus—

Premonitory Earthquakes—Letter of Pliny the Younger to Tacitus,

relating the death of his Uncle, Pliny the Elder—Benevolence of the

Emperor Titus—Herculaneum and Pompeii buried under a muddy alluvium—

Herculaneum first discovered in 1713.

Of all the volcanic eruptions recorded in history there is none more

celebrated than that which, on the 23rd of August, A.D. 79, buried the

towns of Herculaneum and Pompeii under a deluge of mud and ashes. Many

other eruptions have no doubt been on a grander scale, or may have

spread ruin and desolation over a wider area, but never has a volcano,

awakening from the slumber of a thousand years, devastated a more

smiling paradise than the fields of happy Campania, or buried more

beautiful cities.

Before that terrible catastrophe, Mount Vesuvius, now constantly

smoking, even in times of rest, had, ever since the first colonisation

of South Italy by the Greeks, exhibited no signs of volcanic activity.

Even tradition knew of no previous disturbance. No subterranean thunder,

or sulphurous steams, or cast-up ashes, gave token of the fires

slumbering beneath its basis; and the real nature of the apparently so

peaceful mountain could only be conjectured from the similarity of its

structure to other volcanoes, or from the ancient lava-streams that

furrowed its abrupt declivities. At that time also its shape was very

different from its present form, for instead of two apices, it

exhibited, from a distance, the regular outlines of a sharply truncated

cone. Plutarch relates that rough rock walls, piled round its summit,

and overgrown with wild vines, inclosed the waste of the crater.

When, in 73 B.C., Spartacus, with seventy of his comrades, broke the

fetters of an insupportable slavery, he found a secure retreat in this

natural stronghold, which could only be scaled by a single narrow and

difficult path. By degrees 10,000 fugitive slaves gathered round his

standard, and Rome began to tremble for her safety. The prætor Clodius

led an army against the rebels, and surrounded the mountain; but

Spartacus caused ropes to be made of the branches of wild vines, by

means of which he, with the boldest of his followers, was let down from

the rocks, where they were supposed to be totally inaccessible, and,

falling unawares upon the prætor, put his troops to flight and took his

camp. The declivities of the mountain, thus become historically

renowned, were covered with the richest fields and vineyards, and at its

foot, along the beautiful Bay of Naples, lay the flourishing towns of

Herculaneum and Pompeii, the seats of luxury and refinement. Who could,

then, have imagined that this charming scene was so soon to be disturbed

in so terrible a manner, and that the time was nigh when the ancient

volcanic channels, from which, in unknown ages, lava-streams and ashes

had so frequently broken forth, were once more to be re-opened? The

first sign which announced the awakening energies of the volcano was an

earthquake, which, in 63 A.D. devastated the fertile regions of

Campania. From that time to the crowning disaster of 79, slight tremors

of the earth frequently occurred, until, finally, the dreadful eruption

took place which Pliny the Younger so vividly describes in his

celebrated letter to Tacitus.

‘My uncle,’ says the Roman, ‘was at Misenum, where he commanded the

fleet. On the 23rd of August, about one o’clock in the afternoon, my

mother informed him that a cloud of an uncommon size and form was seen

to arise. He had sunned himself (according to the custom of the ancient

Romans), and taken his usual cold bath, then dined, and studied. He

asked for his sandals, and ascended an eminence, from which the

wonderful phenomenon could be plainly seen. The spot from whence the

cloud ascended, in a shape like that of an Italian pine-tree, could not

be ascertained on account of the distance; its arising from Vesuvius

only subsequently became known.

‘In some parts it was white, in others black and spotted, from the ashes

and stones which it carried along. To my uncle, being a learned man, the

phenomenon seemed important, and worthy of a closer investigation. He

ordered a light ship to be got ready, and left it to my option to

accompany him. I answered that I preferred studying, and by chance he

himself had given me something to write. He was on the point of leaving

the house when he received a letter from Resina, the inhabitants of

which, alarmed at the impending danger—the place lay at the foot of the

mountain, and escape was only possible by sea—begged him to help them in

their great distress. He now changed his plan, and executed as a hero

the undertaking to which he had been prompted as a natural philosopher.

‘He ordered the galleys of war to set sail, and embarked to bring help,

not only to Resina, but to many other places along the coast, which, on

account of its loveliness, was very densely peopled.

‘He hastens to the spot from which others are taking flight, and steers

in a direct line towards the seat of danger, so unconcerned as to

dictate his observations upon all the events and changes of the

catastrophe, as they passed before his eyes.

‘Already ashes fell upon the ship, hotter and thicker on approaching, as

also pumice and other stones blackened and burnt by fire. Suddenly a

shallow bottom, and the masses ejected by the eruption, rendered the

coast inaccessible. He hesitated for a moment whether he should sail

back again, but, soon resolved, said to the steersman who advised him to

do so, “Fortune favours the bold; steer towards the villa of

Pomponianus.” This friend resided at Stabiæ, on the opposite side of the

bay, where the danger, although as yet at some distance, was still

within sight, and menacing enough. Pomponianus had therefore caused his

effects to be conveyed on board a ship, intent on flight so soon as the

contrary wind should have abated. As soon as my uncle, to whom it was

very favourable, has landed, he embraces, consoles, encourages his

terrified friend, takes a bath to relieve his fears by his own

confidence, and dines after the bath with perfect composure, or, what is

no less great, with a serene countenance.

‘Meanwhile high columns of flame burst forth from Vesuvius in various

places, their brilliancy being increased by the darkness of the night.

My uncle, with the intention of relieving apprehension, said that they

proceeded from the villas which, abandoned by their terrified

proprietors and left a prey to the flames, were now burning in solitude.

He then retired and slept soundly, for his attendants before the door

heard him fetch his breath, which, on account of his corpulence, was

deep and loud. But now the court, into which the room opened, became

filled to such a height with ashes and pumice that by a longer delay he

would not have been able to leave it. They awaken him, he rises, and

greets Pomponianus and the others who had watched. They consult

together, whether to remain in the house or to flee into the open air,

for the ground trembled from the repeated and violent shocks of the

earth, and seemed to reel backwards and forwards. On the other hand,

they feared in the open air the falling of the pumice-stones and

cinders. On comparing these two dangers, flight was chosen; and, as a

protection against the shower of stones, they covered their heads with

cushions. Everywhere else the day was already far advanced, but the

blackest night still reigned at Stabiæ. Provided with torches, they

resolved to seek the shore, in order to ascertain whether they could

venture to embark, but the sea was found to be too wild and boisterous.

‘My uncle now lay down upon a carpet, and asked for some cold water, of

which he repeatedly drank. The flames and their sulphurous odour drove

away his companions, and forced him to rise. Leaning on two slaves, he

tried to move, but immediately sank down again, suffocated as I believe

by the dense smoke, and by the closing of his larynx, which was by

nature weak, narrow, and subject to frequent spasms. On the third

morning after his death, the body was found without any marks of

violence, covered with the clothes he had worn, and more like a person

sleeping than a corpse.’

Thus perished, in his fifty-sixth year, one of the greatest naturalists

and noblest characters of ancient Rome, the philosopher to whom we are

indebted for the first general description of the world—a work which, in

spite of its numerous imperfections and errors, is one of the most

interesting monuments of classical literature.

When the rage of the volcanic powers had subsided, the sun, now no

longer obscured by clouds of ashes, shone upon a scene of utter

desolation, where nature, embellished by art, had, but a few days

before, appeared in all her loveliness. The mountain itself had changed

its form, and rose with new peaks to the skies; a thick layer of stones

and dust had settled with the curse of sterility on the fields;

thousands of homeless wretches wandered about disconsolate, and three

towns—Pompeii, Herculaneum, Stabiæ—had disappeared to be brought to

light again in a wonderful manner after the lapse of many centuries.

This great catastrophe gave the Emperor Titus a fine opportunity for

displaying the benevolence which entitled him to be called ‘the delight

of mankind.’ He immediately hastened to the scene of destruction,

appointed guardians of consular rank to distribute among the needy

survivors the property of those who had perished without heirs; and

encouraged the weak-hearted, assisting them by liberal donations, until

a no less terrible misfortune recalled him to Rome, where a fire, which

laid almost half the town in ashes, was followed by a plague, which, for

some time, daily swept away thousands.

It has often been asked how so many of the relics buried in Herculaneum

and Pompeii could have been so perfectly preserved as to form a Museum

of the Past for the admiration and instruction of future ages. A stream

of lava would undoubtedly have consumed everything on its fiery track,

but, fortunately for posterity, it was not a flood of molten stone, but

a current of mud which overwhelmed the devoted cities. We learn from

history that a heavy shower of sand, pumice, and lapilli was ejected by

Vesuvius for eight successive days and nights, in the year 79,

accompanied by violent rains, and thus all these volcanic matters were

converted into mud-streams, which, rushing down the sides of the

mountain, descended upon Herculaneum and Pompeii. This circumstance

satisfactorily explains how the _interior_ of the buildings, with all

the underground vaults and cellars, was filled up, and how all the

objects they contained could be as perfectly moulded as in a plaster

cast by the muddy alluvium, which subsequently hardened into pumice

tuff. Hence this wonderful preservation of paintings, which, shielded

from the destructive influence of the atmosphere, still retained their

original freshness of colour when again brought to light by a late

generation; these rolls of papyrus which it has been found possible to

decipher; this perfect cast of a woman’s form, with a child in her arms!

No lava has flowed over Pompeii since that city was buried, but with

Herculaneum the case is different. Although the substance which fills

the interior of the buildings in that doomed city must have been

introduced in a state of mud like that found in similar situations in

Pompeii, yet the superincumbent mass differs wholly in composition and

thickness.

Herculaneum was situated several miles nearer to the volcano, and has,

therefore, been always more liable to be covered, not only by showers of

ashes, but by alluvium and streams of lava. Accordingly, masses of both

have accumulated on each other above the ancient site of the city, to a

depth of nowhere less than 70, and in many places of 112 feet; while the

depth of the bed of ashes under which Pompeii lies buried seldom exceeds

12 or 14 feet above the houses, and it is even said that the higher part

of the amphitheatre always projected above the surface.

Yet, strange to say, Herculaneum, though far more profoundly hidden, was

discovered before Pompeii, by the accidental circumstance that a well

sunk in 1713 came right down upon the theatre where the statues of

Hercules and Cleopatra were found. Many others were afterwards dug out

and sent to France by the Prince of Elbeuf, who, having married a

Neapolitan princess, became proprietor of the field under which the

theatre lies buried. Further excavations were, however, forbidden by

Government, and only resumed in 1736. But the difficulty of removing the

large masses of lava accumulated above the city, and the circumstance of

its partly lying under the modern towns of Portici and Resina have

confined the exploration of Herculaneum within narrow limits. The large

theatre alone is open for inspection, and can be seen only by

torchlight, so that its dark galleries, cut through the tuff, are but

seldom visited by strangers; while no traveller leaves Naples without

having wandered through the ruins of Pompeii, for Italy hardly affords a

more interesting sight than that of these streets and forums, these

theatres and temples, these houses and villas, which require but the

presence of their ancient inhabitants to complete the picture of a Roman

town, such as it was eighteen hundred years ago.

CHAPTER VIII.

GAS SPRINGS AND MUD VOLCANOES.

Carbonic-acid Springs—Grotto del Cane—The Valley of Death in Java—

Exaggerated Descriptions—Carburetted Hydrogen Springs—The Holy Fires

of Baku—Description of the Temple—Mud Volcanoes—The Macaluba in

Sicily—Crimean Mud Volcanoes—Volcanic Origin of Mud Volcanoes.

The numerous gas springs which in many countries are evolved from an

unknown depth, afford us a convincing proof that the remarkable chemical

transformations of which we find so many traces in the past history of

our planet are still perpetually taking place in many of the mysterious

crevices and hollows of the earth-rind. In Auvergne, the Vivarrais, the

Eifel, and along the whole basaltic range from the Rhine to the

Riesengebirge in Silesia, carbonic acid gas is exhaled in incredible

quantities from the vast laboratories of the subterranean world.

Professor Bischoff found that a single gas spring near Burgbrohl daily

produced 5,650 cubic feet of carbonic acid, a quantity amounting in the

course of a year to no less than 262,000 pounds in weight; and,

according to Bromeis, the great Artesian spring at Nauheim evolves every

minute 71 cubic feet of carbonic acid, equal to a weight of 5,000,000

pounds annually. If from these two instances we judge of the produce of

the many carbonic acid gas springs of Germany, and if we farther extend

our view to the rest of the world, in many parts of which carbonic acid

probably escapes in still greater quantities, we can form some idea of

the geological importance of these springs, which also exercise no small

influence upon the organic world. For the incalculable masses of

carbonic acid which are thus constantly pouring from subterranean vents

into the atmospheric ocean are again absorbed by millions of plants.

They feed the forests and the fields; and thus these chemical changes,

which are incessantly but imperceptibly modifying the earth-rind,

ultimately tend to the advantage of man.

As a light dipped in carbonic acid gas is immediately extinguished, and

every animal inhaling it is liable to instant suffocation, these

properties are sometimes made use of for cruel experiments, for which,

among others, the insignificant Grotto del Cane, in the kingdom of

Naples—a cave or hole in the side of a mountain near the Lake Agnano—has

become notorious. Some miserable dogs are thrust into the stratum of

fixed air which covers the bottom of the hole, and are alternately

almost choked and resuscitated to satisfy the idle curiosity of

tourists. Their violent efforts to escape, when about to be plunged into

the poisonous vapour, prove the horrible cruelty of the practice.

The carbonic-acid springs in the glen of the Brohl, a small rivulet

flowing into the Rhine, near Andernach, are turned to a better purpose,

for the manufacture of white lead.

The famous ‘Valley of Death,’ or Poison Valley, in the Island of Java,

is nothing more than a funnel-shaped hollow, measuring about 100 feet in

diameter at the top, and with a bare space in its centre fifteen feet

broad and long, which is frequently covered with a stratum of carbonic

acid gas. The sides of the hollow, and even the bottom, with the

exception of the above-mentioned naked spot, are everywhere clothed with

shrubbery, or even with forest trees.

The dead bodies of stags, tigers, wild boars, and birds are said to have

been frequently found in the hollow; but Dr. Junghuhn, the author of a

classical work on Java, saw in 1838 but one human corpse lying on its

back in the centre of the bare spot. It was still there in 1840, and but

slightly decomposed. In 1845 it had been removed, most likely by some

compassionate wanderers desirous of giving it a decent burial, for not

the slightest trace of the skeleton remained. During the years 1838,

1840, and 1845 Junghuhn visited the Valley of Death no less than

thirteen times. When he last saw it, the bodies of six wild hogs were

lying at the bottom, all more or less in a state of putrefaction. The

crows that were feasting upon their remains proved that a descent might

be effected without danger, for, on seeing them hopping about on the

naked soil, even the Javanese entered the circle without hesitation. Not

a single trace of carbonic acid was to be perceived, not even when the

bold naturalist stretched himself out upon the ground and drew his

breath in the crevices and rents with which it is furrowed. Probably the

gas never rises more than three feet above the level of the soil, as at

this height a luxuriant vegetation begins.

This simple description of an accurate observer forms a strange contrast

to the gross exaggeration of other travellers, whose accounts, copied in

many hand-books, have puffed up a phenomenon hardly superior to that of

the Grotto del Cane into something like an eighth wonder of the world.

Loudon, who in July 1830 visited the Pakamaran (as the natives call the

pit), swells its dimensions to a vast crater about half a mile in

circumference, thickly strewn with skeletons of men, tigers, game, and

birds of all kinds; and another recent traveller goes so far as to give

it an extent of twenty miles.

Next to carbonic acid, but of far less general occurrence, carburetted

hydrogen, which gives rise to the wonderful phenomenon of fiery springs,

is the gas most frequently evolved by volcanic spiracles.

Near Pietra Mala, between Bologna and Florence, on a spot about twelve

feet in diameter, several flames rise from the earth, the largest of

which ascends to a height of five feet, and is seen burning at night

with a pale yellow flame, while its minor satellites around are blue

tipped with white. No doubt many a terrible legend is attached to this

infernal spectacle. Near Barigazzo, between Modena and Pistoja, near the

ruins of Velleji, and in many other parts of the volcanic region of the

Apennines, similar flames gush out of the ground. The neat little town

of Fredonia, in the State of New York, on the eastern shore of Lake

Erie, is lighted by natural springs of carburetted hydrogen, which,

being led into a gasometer, feed the seventy or eighty lamps of the

town. The thrifty and practical Chinese, who have preceded us in so many

useful discoveries, have for centuries made a like use of the many

gaseous emanations in the provinces of Yunnan, Szutschuan, Kuangsi, and

Schansi, by leading the inflammable air in pipes, wherever they want it

for lighting or cooking.

But there is no place in the world more remarkable for its burning

springs than Baku, on the western coast of the Caspian Sea, where the

holy and eternal fires are worshipped by the pious Parsees as the

special symbol of the Almighty.

Like most of the cloisters and convents of the Orient, which are exposed

to the incursions of plundering hordes, Aleschga, the temple dedicated

to the worship of fire, is a fortified square inclosing a large

courtyard, and capable of being defended from the terraced roof. The

outer wall forms at the same time the back of the cells, which front the

yard. Over the entrance gate, which is situated to the north, rises a

high bastion or tower, serving as an additional defence, from the

summit, of which the visitor enjoys after sunset the fantastic view of

the flames which, untarnished by smoke, rise on all sides from rents and

crevices in the neighbouring steppe, and wave their bright summits to

and fro like tongues of fire. In the centre of the court stands a square

tower supported by four columns, and inclosing a basin-like excavation,

three or four feet in diameter, into which the gas is conducted by a

pipe from sources beyond the walls of the temple. Four chimneys at the

four corners of the tower are fed in a similar manner. From the centre

of the tower rises a trident, called _Thirsul_. The Parsees relate that

the Devil once got possession of the earth, and reigned with despotic

fury. But man in his distress prayed to the Almighty, and an angel came

down and planted this identical trident in the earth as a token that the

dominion of his Satanic Majesty had ceased. Round the court are twenty-

two cells, like those of a Catholic convent. They are very small, and,

with the exception of a ragged rug, wholly without furniture; but each

of them is provided with a gas pipe, which can be opened or closed at

pleasure, and furnishes light and warmth to the inmate. Near the temple

a well has been dug fifty feet deep, in which the gas accumulates in

larger quantities. Koch (‘Wanderungen im Oriente,’ 1843–4) tells us that

he here enjoyed a sight more wonderful and surprising than any he had

ever witnessed before. A carpet was spread over the mouth of the well to

prevent the gas from escaping. After a few minutes, a priest seized a

bundle of brushwood, in which a piece of burning paper had been stuck,

and flung it into the well, after quickly removing the carpet. The

strangers had previously been warned to keep at some distance, and the

priest and his assistants likewise ran off as fast as they could. About

half a minute after the fire-brand had been cast into the pit, a

terrific explosion took place, and a vast column of fire, in the shape

of an inverted cone (from the gas spreading out as soon as it emerges

from the pit), ascended to the skies.

How long the fires of Baku may have been burning is unknown, but it is

very probable that they did not exist before the Christian era. No Greek

or Roman author mentions them, and it is not before the tenth century

that Arab writers take notice of Baku and its wonders. When the

Sassanides restored the religion of Zoroaster, the attention of these

fire-worshipping princes was naturally directed to a place where fire

gushes pure and unbidden from the earth. They raised a temple on the

spot, and thousands of pilgrims wandered to the holy fires of Baku. But

when the fanatical Arabs overthrew the Persian Empire, times of

persecution and distress began for the Parsees; and still later they

were almost entirely extirpated by the hordes of Tamerlane. During the

last centuries fire-worshipping was again introduced by the Indians,

who, after the Sefides had ascended the Persian throne, gradually

settled in the Caspian provinces, and whose number must have been

considerable, as travellers inform us that in the latter half of the

seventeenth century 200 rich Indian merchants were residing in the town

of Schemachi. But the anarchical times which followed the usurpation of

Nadir Schah forced most of these Indians to leave their adopted country,

and since then only solitary pilgrims have found their way to Baku. But

the number even of these is constantly diminishing, although the

Russians, to whom the sanctuary now belongs, allow them full freedom of

access. When Koch was at Baku, he found there only five Indians from

Mooltan, whither the majority would gladly have returned, had they but

possessed the necessary means. Their squalid appearance and tattered

raiment formed the strongest imaginable contrast to the splendour of the

element they worshipped. Among them was a Fakir, who had made a vow

constantly to remain in the same position absorbed in religious

contemplation, and who for sixteen years had never moved from the spot.

The burning springs gush out not only from the ground near the temple

and in other parts of the peninsula of Abscheron, but even from the

bottom of the neighbouring Caspian Sea; and as Sir Charles Lyell saw

carburetted hydrogen rise in countless bubbles through the crystal

waters above the falls of the Niagara, and shoot up in bright flames at

the approach of a light, so Dr. Abich mentions a spot in the Gulf of

Baku where the inflammable gas issues with such force, and in so great a

quantity, from the bottom, which is there three fathoms deep, that a

small boat is in danger of being overturned when coming too near it.

As gas springs most frequently occur in districts which have been the

former seats of volcanic action, and as similar exhalations often arise

from still active craters, they are supposed by many geologists to be

the last remaining traces of an expiring volcanic energy. Bischoff

considers the carbonic acid of the German gas springs to be developed by

the decomposition of carbonate of lime by volcanic heat or heated water.

A phenomenon which is sometimes found connected with gas springs is that

of the mud volcanoes, which may be described as cones of a ductile,

unctuous clay, formed by the continued evolution of a sulphurous and

inflammable gas, spurting up waves and lumps of liquid mud. These

remarkable cauldrons are found in many parts of the world, in the Island

of Milo, in Italy, in Iceland, in India, about 120 miles from the mouths

of the Indus, on the coast of Arracan, in Birmah, in Java, Columbia,

Nicaragua, and Trinidad, but probably nowhere on a grander scale than at

either extremity of the chain of the Caucasus, towards the Caspian on

the east and the Sea of Azof on the west, where in the peninsula of

Taman, and on the opposite coast of the Crimea, near Kertsch, vast

numbers of mud volcanoes are scattered, some of them 250 feet high.

Their operations have apparently been going on for countless ages, and

have covered a great extent of land with their products.

[Illustration: MUD VOLCANOES OF TRINIDAD.]

The Macaluba, in Sicily, which owes its name to the Arabs, is the mud

volcano most anciently known. It is mentioned by Plato in his ‘Phædon,’

and has been described by Strabo. It is situated five miles to the north

of Girgenti, on a hill of a conical shape, truncated at the top, and 150

feet high. The summit is a plain half a mile round, and the whole

surface is covered with thick mud. The depth of the mud, which is

supposed to be immense, is unknown. There is not the slightest

appearance of vegetation upon it. In the rainy season the mud is much

softened; the surface is even, and there is a general ebullition over

it, which is accompanied with a very sensible rumbling noise. In the dry

season the mud acquires greater consistency, but its motion still goes

on. The plain assumes a form somewhat convex; a number of little cones

are thrown up, which rarely rise to the height of two feet. Each of them

has a crater, where black mud is seen in constant agitation, and

incessantly emitting bubbles of air. With these the mud insensibly

rises, and as soon as the crater is full of it, it disgorges. The

residue sinks, and the cone has a free crater, until a new emission

takes place.

Such is the ordinary state of the Macaluba; but from time to time the

hill becomes subject to alarming convulsions. Slight earthquake shocks

are felt at the distance of two or three miles, accompanied with

internal noises resembling thunder. These increase for several days, and

are followed at last by a prodigious spout of mud, earth, and stones,

which rises two or three hundred feet in the air.

Similar paroxysmal explosions have been observed in the Caucasian mud

volcanoes. In February 1794, the Obu, in the peninsula of Taman, had an

eruption accompanied with a dreadful noise, and an earthquake which

radiated from the cone, and was felt as far as Ekaterinodor, at a

distance of fifty-five leagues. At the beginning of the eruption flames

were seen, which rose to a prodigious height, and lasted about half an

hour. At the same time dense clouds of smoke escaped from the crater,

and mud and stones were cast up to the height of 3,000 feet. Six streams

of mud, the largest of which was half a mile long, flowed from the

volcano, and their volume is said to have been equal to twenty-two

millions of cubic feet.

Violent eruptive symptoms accompanied the formation of a new mud volcano

in the vicinity of Baku on the Caspian. On November 27, 1827, flames

blazed up to an extraordinary height for three hours, and continued for

twenty hours more to rise about three feet above a crater from which mud

was ejected. At another point in the same district, where flames issued,

fragments of rock, of large size, were hurled up into the air and

scattered around.

The phenomena exhibited by the Macaluba and other mud cauldrons are

certainly very distinct from those of true volcanoes, since no scoriæ or

lava or heated matters of any kind are sent forth, the mud being

described as cold when emitted, although the gas, whose violent escape

throws it up, is sometimes ignited. Hence geologists commonly regard

these phenomena as entirely distinct from the volcanic, and ascribe

their origin to chemical action going on at no great depth beneath the

surface, among the constituents of certain stratified matters; while

other scientific authorities declare them to be as much connected with

internal igneous agency as any other eruptive phenomena. Their

occurrence in districts not remote from the sites of vast volcanic

disturbance, and their occasional violent paroxysms, certainly afford

much support to this view, and show that it is probably the same power,

in different degrees of energy, which casts up the mud of the Macaluba

and pours forth the lava-streams of Cotopaxi.

CHAPTER IX.

EARTHQUAKES.

Extent of Misery inflicted by great Earthquakes—Earthquake Regions—

Earthquakes in England—Great Number of Earthquakes—Vertical and

undulatory Shocks—Warnings of Earthquakes—Sounds attending

Earthquakes—Remarkable Displacements of Objects—Extent and Force of

Seismic Wave Motion—Effects of Earthquakes on the Sea—Enormous Waves

on Coasts—Oscillations of the Ocean—Fissures, Landslips, and

shattering Falls of Rock caused by Earthquakes—Causes of Earthquakes—

Probable Depth of Focus—Opinions of Sir Charles Lyell and Mr. Poulett

Scrope—Impressions produced on Man and Animals by Earthquakes.

Of all the destructive agencies of nature there is none to equal the

earthquake. The hurricane is comparatively weak in its fury; the

volcanic eruption generally confines its rage to the neighbourhood of

the labouring mountain, but a great earthquake may cover a whole land

with ruins.

The terrible subterranean revolution which convulsed all Asia Minor and

Syria in the reign of Tiberius, destroyed twelve celebrated cities in a

single night. The sun, which on setting had gilded their temples and

palaces with his parting rays, beheld them prostrate on the following

morning.

In A.D. 115 Antioch was the centre of a great commotion. The city was

full of soldiers under Trajan; heavy thunder, excessive winds, and

subterranean noises were heard; the earth shook, the houses fell; the

cries of people buried in the ruins passed unheeded. The Emperor leaped

from a window, while mountains were broken and thrown down, and rivers

disappeared, and were replaced by others in a new situation. Four

centuries later (May 20, 526) the same doomed city was totally subverted

by an earthquake, when it is reported that 250,000 persons perished.

Similar catastrophes, in which thousands and thousands of victims were

suddenly destroyed, have frequently occurred in Peru and Chili, in the

West Indies and Central America, in the Moluccas and Java, in the

countries bordering on the Mediterranean and the Red Sea; but a bare

mention of the loss of life conveys but a faint idea of the extent of

misery inflicted by one of those great earthquakes which mark with an

ominous shade many large tracts of the earth’s surface.

We must picture to ourselves the slow lingering death which is the fate

of many—some buried alive, others burnt in the fire which almost

invariably bursts out in a city where hundreds of dwellings have

suddenly been laid prostrate—the numbers who escaped with loss of limbs

or serious bodily injuries, and the surviving multitude, suddenly

reduced to penury and want.

In the Calabrian earthquake of 1783, it is supposed that about a fourth

part of the inhabitants of Polistena and of some other towns were buried

alive, and might have been saved had there been no want of hands; but in

so general a calamity, where each was occupied with his own misfortunes

or those of his family, help could seldom be procured. ‘It frequently

happened,’ says Sir Charles Lyell, ‘that persons in search of those most

dear to them could hear their moans, could recognise their voices, were

certain of the exact spot where they lay buried beneath their feet, yet

could afford them no succour. The piled mass resisted all their

strength, and rendered their efforts of no avail. At Terranuova four

Augustin monks, who had taken refuge in a vaulted sacristy, the arch of

which continued to support a vast pile of ruins, made their cries heard

for the space of four days. One only of the brethren of the whole

convent was saved, and of what avail was his strength to remove the

enormous weight of rubbish which had overwhelmed his companions? He

heard their voices die away gradually, and when afterwards their four

corpses were disinterred, they were found clasped in each other’s arms.’

Affecting narratives are preserved of mothers saved after the fifth,

sixth, and even seventh day of their interment, when their infants or

children had perished with hunger. In his work on the great Neapolitan

earthquake of 1857, Mr. Mallet, from innumerable narratives of personal

peril and sad adventure, selects the distressing case of a noble family

of Monte Murro, as affording a vivid picture of the terrors of an

earthquake night. Don Andrea del Fino, the owner of one of the few

houses in the city which escaped total destruction, was with his wife in

bed, his daughter sleeping in an adjacent chamber on the principal

floor. At the first shock his wife, who was awake, leaped from bed, and

immediately after, a mass of the vaulting above came down, and buried

her sleeping husband. At the same moment, the vault above their

daughter’s room fell in upon her. From the light and hollow construction

of the vaults neither was at once killed. The signora escaped by leaping

from the front window, she scarcely knew how. For more than two hours

she wandered, unnoticed, amongst the mass of terrified survivors in the

streets, before she could obtain aid from her own tenants and

dependants, to extricate her husband. They got him out after more than

eighteen hours’ entombment—alive, indeed, but maimed and lame for life.

His daughter was dead. As he lay longing despairingly for release from

the rubbish, which a second shock, an hour after the first, had so

shaken and closed in around him that he could scarcely breathe, he

heard, but a few feet off, her agonising cries and groans grow fainter

and fainter, until at last they died away. His wife, to whose devotion

his own life was owing, had escaped unhurt.

Unfortunately man too often vies with the brute forces of nature to

increase the horrors of a great earthquake. As the arm of the law is

paralysed by the general panic, thieves and ruffians are not slow to

avail themselves of their opportunity. Thus in the Calabrian catastrophe

of 1783, nothing could be more atrocious than the conduct of the

peasants, who abandoned the farms and flocked in great numbers into the

towns—not to rescue their countrymen from a lingering death, but to

plunder. They dashed through the streets amid tottering walls and clouds

of dust, trampling beneath their feet the bodies of the wounded and half

buried, and often stripping them, while yet living, of their clothes.

From the vast ruin and misery they entail, it is evident that where

earthquakes are frequent, there can never be perfect security of

property even under the best government; and as the fruits collected by

the labour of many years may be lost in an instant, the progress of

civilisation and national wealth must necessarily be retarded.

‘Earthquakes alone,’ says Mr. Darwin, ‘are sufficient to destroy the

prosperity of any country. If beneath England the now inert subterranean

forces should exert those powers which most assuredly in former

geological ages they have exerted, how completely would the entire

condition of the land be changed! What would become of the lofty houses,

thickly packed cities, great manufactories, the beautiful public and

private edifices? If the new period of disturbance were first to

commence by some great earthquake in the dead of the night, how terrific

would be the carnage! England would at once be bankrupt; all papers,

records, and accounts would from that moment be lost. Government, being

unable to collect the taxes, and failing to maintain its authority, the

hand of violence and rapine would remain uncontrolled. In every large

town famine would go forth, pestilence and death following in its

train.’

Fortunately the experience of many ages shows that the regions subject

to these terrible catastrophes are confined to a comparatively small

part of the surface of the globe. Thus Southern Italy and Sicily; the

tract embracing the Canaries, the Azores, Portugal, and Morocco; Asia

Minor, Syria, and the Caucasus; the Arabian shore of the Red Sea; the

East Indian Archipelago; the West Indies, Nicaragua, Quito, Peru, and

Chili, are particularly liable to destructive shocks.

But beyond these limits slighter earthquakes are of far more common

occurrence than is generally supposed, and probably they leave no part

of the world entirely undisturbed. From the year 1821 to 1830 no less

than 115 earthquakes have been felt to the north of the Alps, and since

the year 1089, 225 are cited in the annals of England. Some of these

earthquakes seem to have but just stopped at the point when a slight

increase of their force would have covered the land with ruins. In 1574,

on the 26th of February, between five and six in the evening, an

earthquake was felt at York, Worcester, Hereford, Gloucester, and

Bristol. Norton Chapel was filled with worshippers; they were nearly all

overthrown, and fled in terror, thinking that the dead were unearthed or

that the chapel was falling. Six years later, on the 6th of April, at 6

P.M., all England was thrown into consternation. The great bell at

Westminster began to toll; the students at the Temple started up from

table and rushed into the street, knives in hand; a part of the Temple

Church fell, and stones dropped from St. Paul’s. Two stones fell in

Christ’s Church, and crushed two persons. In rushing out of the church

many were lamed, and there was a shower of chimneys in the streets. At

Sandwich, the occurrence was marked by the violence of the sea, which

made ships run foul of each other; and at Dover a part of the

fortifications fell with the rock which supported it.

On the 6th October 1863, a movement, though gentle when compared to the

preceding instances, was felt from the English Channel to the Mersey,

and from Hereford to Leamington and Oxford. The Malvern range was about

the centre of the area, as it has often been before. Even in alluvial

Holland, six or eight slight earthquakes have been felt during the last

century. The industrious researches of Kluge show that, during the eight

years from 1850 to 1857, no less than 4,620 earthquakes—a great

proportion of which (509) fell to the share of Southern Europe—have been

noticed in both hemispheres; and when we remember that a very

considerable part of the globe is still either totally unknown or

removed by the barbarous condition of its inhabitants from all

intercourse with the scientific world, and that, consequently, the above

list must necessarily be incomplete, it is very probable that not a day

passes without some agitation of the surface of the earth in some place

or other.

A violent earthquake almost always consists of several shocks following

each other in rapid succession. Sometimes they are preceded by slighter

vibrations; at other times they suddenly convulse the land without any

previous notice. In most instances, each shock lasts but a few seconds;

but this is enough to ruin the work of ages. Three violent commotions

within five minutes destroyed the town of Caraccas on March 26, 1812;

and the earthquake which, in 1692, desolated Jamaica lasted but three

minutes. On January 11, 1839, two shocks within thirty seconds covered

Martinique, and the whole range of the Lesser Antilles, with ruins. But

a violent earthquake, though itself but of short duration, is generally

followed by a series of secondary shocks, which are repeated at

gradually widening intervals and with decreasing energy, so that if

these subsequent tremors be taken into account, it may often be said to

last for weeks, or even months. Thus, to cite but one instance, the

earthquake of October 21, 1766, destroyed the whole town of Cumana in a

few minutes, but during the following fourteen months the earth was in a

constant vibratory motion, and scarce an hour passed without a shock

being felt.

In countries where earthquakes are comparatively rare (for instance in

the south of Europe) the belief is very general that oppressive heat,

stillness of the air, and a misty horizon are always forerunners of the

phenomenon. But this popular opinion is not confirmed by the experience

of trustworthy observers, who have lived for years in countries such as

Cumana, Quito, Peru, and Chili, where the ground trembles frequently and

violently. Humboldt experienced earthquakes during every state of the

weather, serene and dry, rainy and stormy.

Brute animals, being more sensitive than men of the slightest movement

of the earth, are said to evince extraordinary alarm, and it has been

often observed that even the dull hog shows symptoms of uneasiness

previous to the shock. During the great Neapolitan earthquake of 1857 an

unusual halo-like light was seen in the sky before, and not long before,

the shock. Mr. Mallet was at first inclined to look upon this notion as

a superstitious tale; but, finding it widely diffused in a country where

communication is bad and news travels slowly, no longer doubted that it

was founded on fact.[10] Conjectures would be useless as to its nature,

but future observation directed to the point may determine whether some

sort of auroral light may emanate from the vast depths of rock formation

under the enormous tensions and compressions that must precede the final

crash and rupture; or whether volcanic action, going on in the unseen

depths below, may give rise to powerful disturbances of electric

equilibrium, and hence to the development of light; just as from

volcanic mountains in eruption lightnings continually flash from the

huge volumes of steam and floating ashes above the crater. Humboldt is

also of opinion that, though in general the revolutions which take place

below the surface of the earth are not announced beforehand by any

meteorological process, or a peculiar appearance of the sky, it is not

improbable that during violent shocks some change may occur in the

condition of the atmosphere. Thus, during the earthquake in the

Piedmontese valleys of Pelis and Clusson, great alterations were

observed in the electrical tension of the atmosphere without any

appearance of a thunder-storm.

Footnote 10:

Mallet, ‘The Great Neapolitan Earthquake of 1857,’ vol. i. p. 323.

Earthquakes are generally attended with sounds, sometimes like the

howling of a storm, or the rumbling of subterranean thunder, at others

like the clashing of iron chains, or as if a number of heavily laden

waggons were rolling rapidly over the pavement, or as if enormous masses

of glass were suddenly shivered to pieces. As solid bodies are excellent

conductors of sound (burnt clay, for instance, propagating it ten or

twelve times more rapidly than the air), the subterranean noise may be

heard at a vast distance from the primary seat of the earthquake. In

Caraccas, in the grass-plains of Calabozo, and on the banks of the Rio

Apure, which falls into the Orinoco, a dreadful thunder-like sound was

everywhere heard on April 30, 1812, without any simultaneous trembling

of the earth, at the time when, at the distance of 158 geographical

miles, the volcano of St. Vincent, in the Lesser Antilles, was pouring

out of its crater a mighty lava-stream. This was, according to distance,

as if an eruption of Vesuvius were heard in the north of France. In the

year 1744, during the great eruption of the volcano Cotopaxi, a

subterranean noise like the firing of cannon was heard at Honda on the

Magdalena river. But the crater of Cotopaxi is 17,000 feet higher than

Honda, and both points, situated at a distance of 109 geographical

miles, are moreover separated by the colossal mountain masses of Quito,

Pasto, and Popayan, and by numberless ravines and deep valleys. The

sound was certainly transmitted, not through the air, but through the

earth, and must have proceeded from a very considerable depth.

But noise is not the necessary attendant of an earthquake, for many

instances are known in which the most violent shocks have been

completely noiseless. No subterranean sounds were heard during the

terrific earthquake which destroyed Riobamba on February 4, 1797, and

the same circumstance is mentioned in the narratives of many of the

Chilian earthquakes.

The phenomenon of sound, when unaccompanied by any perceptible

vibration, makes a peculiarly deep impression on the mind, even of those

who have long inhabited a country subject to frequent earthquakes. They

tremble at the idea of the catastrophe which may follow. A remarkable

instance of a long protracted noise without any trembling of the earth

occurred in 1784, at the wealthy mining town of Guanaxuato in Mexico,

where the rolling of subterranean thunder, with now and then a louder

crash, was heard for more than a month, without the slightest shock,

either on the surface of the earth, or in the neighbouring silver mines,

which are 1,500 feet deep. The noise was confined to a small space, so

that a few miles from the town it was no longer audible. Never before

had this phenomenon been known to occur in the Mexican highlands, nor

has it been repeated since.

Earthquake shocks are either vertical or undulatory. A vertical shock,

which is felt immediately above the seat or focus of the subterranean

disturbance, causes a movement up and down. Like an exploding mine, it

frequently jerks movable bodies high up into the air. Thus, during the

great earthquake of Riobamba, the bodies of many of the inhabitants were

thrown upon the hill of La Culla, which rises to the height of several

hundred feet at the other side of the Lican torrent; and during the

earthquake of Chili in 1837, a large mast, planted thirty feet deep in

the ground at Fort San Carlos, and propped with iron bars, was thrown

upwards, so that a round hole remained behind.

Although to the inhabitants of a shaken district the undulatory wave or

vibration of an earthquake appears to radiate horizontally outwards from

the spot on the surface where it is first felt, the force does not

really operate in a horizontal direction, like a wave caused by a pebble

on the surface of a pond; for at every point, except that immediately

above the focus of the shock, it comes up obliquely from below, causing

the ground to move forwards and then backwards in a, more or less

horizontal direction. As a ship, yielding to the oscillatory movements

of the waves, alternately inclines to one side or the other, so, during

the more violent undulations of the soil, the objects on its surface are

momentarily moved from their vertical position, and often considerably

inclined towards the horizon. Thus during the great earthquake which

convulsed the valley of the Mississippi in 1811–12, Mr. Bringier, an

engineer of New Orleans, who was on horseback near New Madrid, where

some of the severest shocks were experienced, saw the trees bend as the

wave-motion of the earthquake passed under them, and immediately

afterwards recover their position. The transit of the wave through the

woods was marked by the crash of countless branches, first heard on one

side and then on the other. It must have been awful to see the giants of

the forest thus move to and fro like a corn-field agitated by the wind!

Very remarkable displacements of objects are not seldom caused by

earthquakes, such as the rotation of the blocks of columns or the

turning of statues on their pedestals.

At Lima, which, owing to its repeated destructions by earthquakes, is

properly a city of ruins, Professor Dana saw two obelisks with the upper

stone on each displaced and turned round on its axis about fifteen

degrees in a direction from north to east. These rotations by

earthquakes have been attributed by some authors to an actual rotatory

movement in the earthquake vibration; but it has lately been shown by

Mr. Mallet that this hypothesis is untenable and unnecessary, as a

simple vibration back and forth is all that is required to produce a

rotatory motion in the stone of a column, provided that stone be

attached below more strongly on one side of the centre than on the

opposite.

The wave-motion of an earthquake sometimes spreads over enormous spaces.

The shocks of the earthquake of New Granada which took place in the

night from the 16th to the 17th of June 1826, were noticed over a

surface of 750,000 square miles. The earthquake of Valdivia (February

20, 1835) was felt southwards on the distant island of Chiloe to the

north as far as Copiapo, in Mendoza to the east of the Andes, and on the

Island of Juan Fernandez, 300 miles from the coast. Supposing these

effects to have taken place at corresponding distances in Europe, all

the land would have trembled from the North Sea to the Mediterranean,

and from Ireland to the centre of France.

It is evident that the extent and force of the wave-motion of an

earthquake must in a great measure depend upon the nature of the rocks

through which it is transmitted. It will vibrate more easily through

solid homogeneous masses, while in alluvial deposits, or in a soil

composed of sand and loose conglomerate, its undulations will be

propagated irregularly and its effects be far more destructive. This is

particularly the case where the alluvial deposits repose on a substratum

of hard rock. Thus the devastations of the Calabrian earthquake of 1783

were most apparent in the plain of Oppido, in those parts where the

newer tertiary strata rest upon granite. The earthquake wave generally

follows the direction of mountain-chains, and but rarely crosses them.

The great Chilian earthquakes, which often propagate their vibrations to

distances of many hundred miles along the western foot of the Andes,

remain unfelt on their eastern border; while the earthquakes along the

shores of Venezuela, Caraccas, and New Granada rarely transmit their

vibrations beyond the high mountain-chains which run parallel with the

coast. This is probably due to the numerous dislocations, rents, and

caverns which are produced by the elevation of the mountain-chains, and

necessarily serve as barriers to the propagation of the earthquake wave.

Severe earthquakes are not seldom accompanied by a violent agitation of

the sea. First, at the instant of the shock, the water swells high up on

the beach with a gentle motion, and then as quietly recedes; secondly,

some time afterwards, the whole body of the sea retires from the coast,

and then returns in waves of overwhelming force. The first movement

seems to be an immediate consequence of the earthquake affecting

differently a fluid and a solid, so that their respective levels are

slightly deranged; but the second is a far more important phenomenon.

‘Some authors,’ says Mr. Darwin, ‘have attempted to explain it by

supposing that the sea retains its level, while the land oscillates

upwards; but surely the water close to the land, even on a rather steep

coast, would partake of the motion of the bottom; moreover, similar

movements of the sea have occurred at islands far distant from the chief

line of disturbance. I suspect (but the subject is a very obscure one)

that a wave, however produced, _first draws the water from the shore_ on

which it is advancing to break. I have observed that this happens with

the little waves from the paddles of a steamboat. From the great wave

not immediately following the earthquake, but sometimes after the

interval of even half-an-hour, and from distant islands being affected

similarly with the coasts near the focus of the disturbance, it appears

that the wave first rises in the offing, and, as this is of general

occurrence, the cause must be general. I suspect we must look to the

line where the less disturbed waters of the deep ocean join the water

nearer the coast which has partaken of the movements of the land, as the

place where the great wave is first generated; it would also appear that

the wave is larger or smaller according to the extent of shoal water

which has been agitated together with the bottom on which it rested.’

The following examples sufficiently prove that no storm, however

violent, is capable of raising such prodigious waves as an earthquake.

In the year 1692 the town of Kingston in Jamaica was almost totally

destroyed by a huge earthquake wave. A frigate which lay in port was

carried forwards over the houses and stranded in the middle of the town.

In his ‘Principles of Geology,’ Sir Charles Lyell relates that, during

the Calabrian earthquake of 1783 the Prince of Scilla had persuaded a

great part of his vassals to betake themselves to their fishing boats

for safety, and he himself had gone on board. On the night of February

5, when some of the people were sleeping in the boats, and others on a

level plain slightly elevated above the sea, the earth rocked and large

masses of rock were thrown down with a dreadful crash upon the plain.

Immediately afterwards the sea, rising more than twenty feet above the

level of this low tract, rolled foaming over it and swept away the

multitude. It then retreated, but soon rushed back again with greater

violence, bringing back with it some of the bodies it had carried away.

At the same time every boat was sunk or dashed against the beach, and

some of them were swept far inland. The aged prince was killed, with

1,430 of his people.

After the earthquake which devastated the town of Lima on the 28th of

October 1746, the sea rose on the evening of the same day eighty feet

above its usual level in the neighbouring Bay of Callao, overwhelmed the

town, and destroyed nearly all the inhabitants. Of the twenty-three

ships which were lying in the harbour at the time, nineteen immediately

sank, while the four others were thrown upon the land at the distance of

nearly a league.

Shortly after the shock which desolated Chili on the 20th of February

1835, a great wave was seen from the distance of three or four miles,

approaching in the middle of the Bay of Talcahuano with a smooth

outline, but tearing up cottages and trees along the shore, as it swept

onwards with irresistible force. At the head of the bay it broke in a

fearful line of white breakers, which rushed up to a height of twenty-

three vertical feet above the highest spring tides. Their force must

have been prodigious, for at the Fort a cannon with its carriage,

estimated at four tons in weight, was moved fifteen feet inwards. The

whole coast was strewed over with timber and furniture, as if a thousand

ships had been wrecked. As Mr. Darwin walked along the shore, he

observed that numerous fragments of rock, which, from the marine

productions adhering to them, must recently have been lying in deep

water, had been cast up high on the beach. One of these was six feet

long, three broad, and two thick.