In size, volcanoes vary from mere mounds a few yards in diameter, such

as the salses or mud volcanoes near the Caspian, to Etna, 10,800 feet

high, with a base 30 miles in diameter; Cotopaxi, in the Andes, 18,887

feet high; or Mauna Loa, in the Sandwich Isles, 13,700 feet high; with

a base 70 miles in diameter, and two craters, one of which, Kilauea, the

largest active crater on our earth, is seven miles in circuit. Larger

extinct craters occur in Japan; but all our terrestrial volcanic

mountains are dwarfed by those observed on the surface of the moon,

which, owing to its smaller size, has cooled more rapidly than our

earth. It is, of course, the explosive force from below which keeps

the crater clear, as a cup-shaped hollow, truncating the cone; and all

stones falling into it would be only thrown out again. It may at the

close of an eruption cool down so completely that a lake can form within

it, such as Lake Averno, near Naples; or it may long remain a seething

sea of lava, such as Kilauea; or the lava may find one or more outlets

from it, either by welling over its rim, which it will then generally

break down, as in many of the small extinct volcanoes (“puys”) of

Auvergne, or more usually by bursting through the sides of the cone.

LAVA VARIES VERY MUCH IN LIQUIDITY

It is not generally until the volcano has exhausted its first explosive

force that lava begins to issue. Several streams may issue in different

directions. Their dimensions are sometimes enormous. Lava varies very

much in liquidity and in the rate at which it flows. This much depends,

however, upon the slope it has to traverse. A lava stream at Vesuvius

ran three miles in four minutes, but took three hours to flow the next

three miles, while a stream from Mauna Loa ran eighteen miles in two

hours. Glowing at first as a white-hot liquid, the lava soon cools at

the surface to red and then to black; cinder-like scoriaceous masses

form on its surface and in front of the slowly-advancing mass; clouds of

steam and other vapor rise from it, and little cones are thrown up

from its surface; but many years may elapse before the mass is cooled

through. Thus, while the surface is glassy, the interior becomes

crystalline.

As to what are the causes of the great convulsions of nature known as

the volcano and the earthquake we know very little. Various theories

have been advanced, but nothing by any means sure has been discovered,

and considerable difference of opinion exists. In truth we know so

little concerning the conditions existing in the earth’s interior

that any views concerning the forces at work there must necessarily be

largely conjectural.

Sir Robert S. Ball says, in this connection: “Let us take, for instance,

that primary question in terrestrial physics, as to whether the interior

of the earth is liquid or solid. If we were to judge merely from the

temperatures reasonably believed to exist at a depth of some twenty

miles, and if we might overlook the question of pressure, we should

certainly say that the earth’s interior must be in a fluid state. It

seems at least certain that the temperatures to be found at depths of

two score miles, and still more at greater depths, must be so high that

the most refractory solids, whether metals or minerals, would at once

yield if we could subject them to such temperatures in our laboratories.

But none of our laboratory experiments can tell us whether, under the

pressure of thousands of tons on the square inch, the application of

any heat whatever would be adequate to transform solids into liquids.

It may, indeed, be reasonably doubted whether the terms solid and

liquid are applicable, in the sense in which we understand them, to the

materials forming the interior of the earth.

“A principle, already well known in the arts, is that many, if not all,

solids may be made to flow like liquids if only adequate pressure be

applied. The making of lead tubes is a well-known practical illustration

of this principle, for these tubes are formed simply by forcing solid

lead by the hydraulic press through a mould which imparts the desired

shape.

“If then a solid can be made to behave like a liquid, even with such

pressures as are within our control, how are we to suppose that the

solids would behave with such pressures as those to which they are

subjected in the interior of the earth? The fact is that the terms solid

and liquid, at least as we understand them, appear to have no physical

meaning with regard to bodies subjected to these stupendous pressures,

and this must be carefully borne in mind when we are discussing the

nature of the interior of the earth.”

THE VOLCANO A SAFETY VALVE

Whatever be the state of affairs in the depths of the earth’s crust, we

may look upon the volcano as a sort of safety-valve, opening a passage

for the pent-up forces to the surface, and thus relieving the earth from

the terrible effects of the earthquake, through which these imprisoned

powers so often make themselves felt. Without the volcanic vent there

might be no safety for man on the earth’s unquiet face.

Professor J. C. Russell, of Michigan University, presents the following

views concerning the status and action of volcanoes:--

“When reduced to its simplest terms, a volcano may be defined as a

tube, or conduit, in the earth’s crust, through which the molten rock is

forced to the surface. The conduit penetrates the cool and rigid rocks

forming the superficial portion of the earth, and reaches its highly

heated interior.

“The length of volcanic conduits can only be conjectured, but, judging

from the approximately known rate of increase of heat with depth (on an

average one degree Fahrenheit for each sixty feet), and the temperature

at which volcanic rocks melt (from 2,300 to 2,700 degrees Fahrenheit,

when not under pressure), they must seemingly have a depth of at least

twenty miles. There are other factors to be considered, but in general

terms it is safe to assume that the conduits of volcanoes are irregular

openings, many miles in depth, which furnish passageways for molten

rock (lava) from the highly-heated sub-crust portion of the earth to its

surface. . . .”

ERUPTIONS OF QUIET TYPE

“During eruptions of the quiet type, the lava comes to the surface in a

highly liquid condition--that is, it is thoroughly fused, and flows with

almost the freedom of water. It spreads widely, even on a nearly level

plain, and may form a comparatively thin sheet several hundred square

miles in area, as has been observed in Iceland and Hawaii. On the Snake

River plains, in Southern Idaho, there are sheets of once molten rock

which were poured out in the manner just stated, some four hundred

square miles in area and not over seventy-five feet in average

thickness. When an eruption of highly liquid lava occurs in a

mountainous region, the molten rock may cascade down deep slopes and

flow through narrow valleys for fifty miles or more before becoming

chilled sufficiently to arrest its progress. Instances are abundant

where quiet eruptions have occurred in the midst of a plain, and

built up ‘lava cones,’ or low mounds, with immensely expanded bases.

Illustrations are furnished in Southern Idaho, in which the cones formed

are only three hundred or four hundred feet high, but have a breadth at

the base of eight or ten miles. In the class of eruption illustrated

by these examples, there is an absence of fragmental material, such as

explosive volcanoes hurl into the air, and a person may stand within

a few yards of a rushing stream of molten rock, or examine closely the

opening from which it is being poured out, without danger or serious

inconvenience.

“The quiet volcanic eruptions are attended by the escape of steam or

gases from the molten rock, but the lava being in a highly liquid

state, the steam and gases dissolved in it escape quietly and without

explosions. If, however, the molten rock is less completely fluid, or

in a viscous condition, the vapors and gases contained in it find

difficulty in escaping, and may be retained until, becoming concentrated

in large volume, they break their way to the surface, producing violent

explosions. Volcanoes in which the lava extruded is viscous, and the

escape of steam and gases is retarded until the pent-up energy bursts

all bounds, are of the explosive, type. One characteristic example is

Vesuvius.

“When steam escapes from the summit of a volcanic conduit--which, in

plain terms, is a tall vessel filled with intensely hot and more or less

viscous liquid--masses of the liquid rock are blown into the air, and on

falling build up a rim or crater about the place of discharge. Commonly

the lava in the summit portion of a conduit becomes chilled and perhaps

hardened, and when a steam explosion occurs this crust is shattered and

the fragments hurled into the air and contributed to the building of the

walls of the inclosing crater.

“The solid rock blown out by volcanoes consists usually of highly

vesicular material which hardened on the surface of the column of lava

within a conduit and was shattered by explosions beneath it. These

fragments vary in size from dust particles up to masses several feet in

diameter, and during violent eruptions are hurled miles high. The larger

fragments commonly fall near their place of origin, and usually furnish

the principal part of the material of which craters are built, but the

gravel-like kernels, lapilli, may be carried laterally several miles

if a wind is blowing, while the dust is frequently showered down on

thousands of square miles of land and sea. The solid and usually angular

fragments manufactured in this manner vary in temperature, and may still

be red hot on falling.

“Volcanoes of the explosive type not uncommonly discharge streams of

lava, which may flow many miles. In certain instances these outwellings

of liquid rock occur after severe earthquakes and violent explosions,

and may have all the characteristics of quiet eruptions. There is

thus no fundamental difference between the two types into which it is

convenient to divide volcanoes.”

MOUNTAINS BLOW THEIR HEADS OFF

“In extreme examples of explosive volcanoes, the summit portion of a

crater, perhaps several miles in circumference and several thousand feet

high, is blown away. Such an occurrence is recorded in the case of

the volcano Coseguina, Nicaragua, in 1835. Or, an entire mountain may

disappear, being reduced to lapilli and dust and blown into the air, as

in the case of Krakatoa, in the Straits of Sunda, in 1883.

“The essential feature of a volcano, as stated above, is a tube or

conduit, leading from the highly heated sub-crust portion of the earth

to the crater and through which molten rock is forced upward to the

surface. The most marked variations in the process depend on the

quantity of molten rock extruded, and on the freedom of escape of the

steam and gases contained in the lava.

“The cause of the rise of the molten rock in a volcano is still a matter

for discussion. Certain geologists contend that steam is the sole motive

power; while others consider that the lava is forced to the surface

owing to pressure on the reservoir from which it comes. The view perhaps

most favorably entertained at present, in reference to the general

nature of volcanic eruptions, is that the rigid outer portion of the

earth becomes fractured, owing principally to movements resulting from

the shrinking of the cooling inner mass, and that the intensely hot

material reached by the fissures, previously solid owing to pressure,

becomes liquid when pressure is relieved, and is forced to the surface.

As the molten material rises it invades the water-charged rocks near

the surface and acquires steam, or the gases resulting from the

decomposition of water, and a new force is added which produces the

most conspicuous and at times the most terrible phenomena accompanying

eruptions.”

The active agency of water is strongly maintained by many geologists,

and certainly gains support from the vast clouds of steam given off by

volcanoes in eruption and the steady and quiet emission of steam from

many in a state of rest. The quantities of water in the liquid state,

to which is due the frequent enormous outflows of mud, leads to the

same conclusion. Many scientists, indeed, while admitting the agency of

water, look upon this as the aqueous material originally pent up

within the rocks. For instance Professor Shaler, dean of the Lawrence

Scientific School, says:

“Volcanic outbreaks are merely the explosion of steam under high

pressure, steam which is bound in rocks buried underneath the surface

of the earth and there subjected to such tremendous heat that when the

conditions are right its pent-up energy breaks forth and it shatters

its stone prison walls into dust. The process by which the water becomes

buried in this manner is a long one. Some contend that it leaks down

from the surface of the earth through fissures in the outer crust, but

this theory is not generally accepted. The common belief is that water

enters the rocks during the crystalization period, and that these rocks

through the natural action of rivers and streams become deposited in the

bottom of the ocean. Here they lie for many ages, becoming buried deeper

and deeper under masses of like sediment, which are constantly being

washed down upon them from above. This process is called the blanketing

process.

“Each additional layer of sediment, while not raising the level of the

sea bottom, buries the first layers just so much the deeper and adds to

their temperature just as does the laying of extra blankets on a bed.

When the first layer has reached a depth of a few thousand feet the

rocks which contain the water of crystalization are subjected to a

terrific heat. This heat generates steam, which is held in a state of

frightful tension in its rocky prison. Wrinklings in the outer crust of

the earth’s surface occur, caused by the constant shrinking of the earth

itself and by the contraction of the outer surface as it settles on the

plastic centers underneath. Fissures are caused by these foldings, and

as these fissures reach down into the earth the pressure is removed from

the rocks and the compressed steam in them, being released, explodes

with tremendous force.”

This view is, very probably, applicable to many cases, and the

exceedingly fine dust which so often rises from volcanoes has,

doubtless, for one of its causes the sudden and explosive conversion of

water into steam in the interior of ejected lava, thus rending it into

innumerable fragments. But that this is the sole mode of action of water

in volcanic eruptions is very questionable. It certainly does not agree

with the immense volumes at times thrown out, while explosions of

such extreme intensity as that of Krakatoa very strongly lead to the

conclusion that a great mass of water has made its way through newly

opened fissures to the level of molten rock, and exploded into steam

with a suddenness which gave it the rending force of dynamite or the

other powerful chemical explosives.

As the earthquake is so intimately associated with the volcano the

causes of the latter are in great measure the causes of the former, and

the forces at work frequently produce a more or less violent quaking of

the earth’s surface before they succeed in opening a channel of escape

through the mountain’s heart. One agency of great potency, and one whose

work never ceases, has doubtless much to do with earthquake action.

In the description of this we cannot do better than to quote from “The

Earth’s Beginning” of Sir Robert S. Ball.

CAUSE OF EARTHQUAKES

“As to the immediate cause of earthquakes there is no doubt considerable

difference of opinion. But I think it will not be doubted that an

earthquake is one of the consequences, though perhaps a remote one, of

the gradual loss of internal heat from the earth. As this terrestrial

heat is gradually declining, it follows from the law that we have

already so often had occasion to use that the bulk of the earth must be

shrinking. No doubt the diminution in the earth’s diameter due to the

loss of heat must be exceedingly small, even in a long period of time.

The cause, however, is continually in operation, and, accordingly, the

crust of the earth has from time to time to be accommodated to the fact

that the whole globe is lessening. The circumference of our earth at

the equator must be gradually declining; a certain length in that

circumference is lost each year. We may admit that loss to be a quantity

far too small to be measured by any observations as yet obtainable, but,

nevertheless, it is productive of phenomena so important that it cannot

be overlooked.

“It follows from these considerations that the rocks which form the

earth’s crust over the surface of the continents and the islands, or

beneath the bed of the ocean, must have a lessening acreage year

by year. These rocks must therefore submit to compression, either

continuously or from time to time, and the necessary yielding of the

rocks will in general take place in those regions where the materials

of the earth’s crust happen to have comparatively small powers of

resistance. The acts of compression will often, and perhaps generally,

not proceed with uniformity, but rather with small successive shifts,

and even though the displacements of the rocks in these shifts be

actually very small, yet the pressures to which the rocks are subjected

are so vast that a very small shift may correspond to a very great

terrestrial disturbance.

“Suppose, for instance, that there is a slight shift in the rocks on

each side of a crack, or fault, at a depth of ten miles. It must be

remembered that the pressure ten miles down would be about thirty-five

tons to the square inch. Even a slight displacement of one extensive

surface over another, the sides being pressed together with a force of

thirty-five tons on the square inch, would be an operation necessarily

accompanied by violence greatly exceeding that which we might expect

from so small a displacement if the forces concerned had been of more

ordinary magnitude. On account of this great multiplication of the

intensity of the phenomenon, merely a small rearrangement of the

rocks in the crust of the earth, in pursuance of the necessary work of

accommodating its volume to the perpetual shrinkage, might produce an

excessively violent shock, extending far and wide. The effect of such a

shock would be propagated in the form of waves through the globe, just

as a violent blow given at one end of a bar of iron by a hammer is

propagated through the bar in the form of waves. When the effect of this

internal adjustment reaches the earth’s surface it will sometimes be

great enough to be perceptible in the shaking it gives that surface. The

shaking may be so violent that buildings may not be able to withstand

it. Such is the phenomenon of an earthquake.

“When the earth is shaken by one of those occasional adjustments of the

crust which I have described, the wave that spreads like a pulsation

from the centre of agitation extends all over our globe and is

transmitted right through it. At the surface lying immediately over the

centre of disturbance there will be a violent shock. In the surrounding

country, and often over great distances, the earthquake may also be

powerful enough to produce destructive effects. The convulsion may also

be manifested over a far larger area of country in a way which makes the

shock to be felt, though the damage wrought may not be appreciable.

But beyond a limited distance from the centre of the agitation the

earthquake will produce no destructive effects upon buildings, and

will not even cause vibrations that would be appreciable to ordinary

observation.”

THE RADIUS OF DISTURBANCE.

“In each locality in which earthquakes are chronic it would seem as if

there must be a particularly weak spot in the earth some miles below

the surface. A shrinkage of the earth, in the course of the incessant

adjustment between the interior and the exterior, will take place by

occasional little jumps at this particular centre. The fact that there

is this weak spot at which small adjustments are possible may provide,

as it were, a safety-valve for other places in the same part of

the world. Instead of a general shrinking, the materials would be

sufficiently elastic and flexible to allow the shrinking for a very

large area to be done at this particular locality. In this way we may

explain the fact that immense tracts on the earth are practically free

from earthquakes of a serious character, while in the less fortunate

regions the earthquakes are more or less perennial.

“Now, suppose an earthquake takes place in Japan, it originates a series

of vibrations through our globe. We must here distinguish between the

rocks--I might almost say the comparatively pliant rocks--which form

the earth’s crust, and those which form the intensely rigid core of the

interior of our globe. The vibrations which carry the tidings of the

earthquake spread through the rocks on the surface, from the centre of

the disturbance, in gradually enlarging circles. We may liken the spread

of these vibrations to the ripples in a pool of water which diverge from

the spot where a raindrop has fallen. The vibrations transmitted by

the rocks on the surface, or on the floor of the ocean, will carry the

message all over the earth. As these rocks are flexible, at all

events by comparison with the earth’s interior, the vibrations will be

correspondingly large, and will travel with vigor over land and under

sea. In due time they reach, say the Isle of Wight, where they set the

pencil of the seismometer at work. But there are different ways round

the earth from Japan to the Isle of Wight, the most direct route being

across Asia and Europe; the other route across the Pacific, America, and

the Atlantic. The vibrations will travel by both routes, and the former

is the shorter of the two.”

TRANSMISSIONS OF VIBRATIONS

Some brief repetition may not here be amiss as to the products of

volcanic action, of which so much has been said in the preceding

pages, especially as many of the terms are to some extent technical in

character. The most abundant of these substances is steam or water-gas,

which, as we have seen, issues in prodigious quantities during every

eruption. But with the steam a great number of other volatile materials

frequently make their appearance. Though we have named a number of these

at the beginning of this chapter, it will not be out of order to

repeat them here. The chief among these are the acid gases known as

hydrochloric acid, sulphurous acid, sulphuretted hydrogen, carbonic

acid, and boracic acid; and with these acid gases there issue hydrogen,

nitrogen ammonia, the volatile metals arsenic, antimony, and mercury,

and some other substances. These volatile substances react upon one

another, and many new compounds are thus formed. By the action of

sulphurous acid and sulphuretted hydrogen on each other, the sulphur

so common in volcanic districts is separated and deposited. The

hydrochloric acid acts very energetically on the rocks around the vents,

uniting with the iron in them to form the yellow ferric-chloride, which

often coats the rocks round the vent and is usually mistaken by casual

observers for sulphur.

Some of the substances emitted by volcanic vents, such as hydrogen and

sulphuretted hydrogen, are inflammable, and when they issue at a high

temperature these gases burst into flame the moment that they come

into contact with the air. Hence, when volcanic fissures are watched at

night, faint lambent flames are frequently seen playing over them, and

sometimes these flames are brilliantly colored, through the presence

of small quantities of certain metallic oxides. Such volcanic flames,

however, are scarcely ever strongly luminous, and the red, glowing light

which is observed over volcanic mountains in eruption is due to quite

another cause. What is usually taken for flame during a volcanic

eruption is simply, as we have before stated, the glowing light of the

surface of a mass of red-hot lava reflected from the cloud of vapor and

dust in the air, much as the lights of a city are reflected from the

water vapor of the atmosphere during a night of fog.

Besides the volatile substances which issue from volcanic vents,

mingling with the atmosphere or condensing upon their sides, there

are many solid materials ejected, and these may accumulate around the

orifice’s till they build up mountains of vast dimensions, like Etna,

Teneriffe, and Chimborazo. Some of these solid materials are evidently

fragments of the rock-masses, through which the volcanic fissure has

been rent; these fragments have been carried upwards by the force of

the steam-blast and scattered over the sides of the volcano. But the

principal portion of the solid materials ejected from volcanic orifices

consists of matter which has been extruded from sources far beneath the

surface, in highly-heated and fluid or semi-fluid condition.

It is to these materials that the name of “lavas” is properly applied.

Lavas present a general resemblance to the slags and clinkers which

are formed in our furnaces and brick-kilns, and consist, like them, of

various stony substances which have been more or less perfectly fused.

When we come to study the chemical composition and the microscopical

structure of lavas, however, we shall find that there are many respects

in which they differ entirely from these artificial products, they

consisting chiefly of felspar, or of this substance in association with

augite or hornblende. In texture they may be stony, glassy, resin-like,

vesicular or cellular and light in weight, as in the case of pumice or

scoria.

FLOATING PUMICE

The steam and other gases rising through liquid lava are apt to produce

bubbles, yielding a surface froth or foam. This froth varies greatly

in character according to the nature of the material from which it is

formed. In the majority of cases the lavas consist of a mass of crystals

floating in a liquid magma, and the distension of such a mass by the

escape of steam from its midst gives rise to the formation of the rough

cindery-looking material to which the name of “scoria” is applied. But

when the lava contains no ready-formed crystals, but consists entirely

of a glassy substance in a more or less perfect state of fusion,

the liberation of steam gives rise to the formation of the beautiful

material known as “pumice.” Pumice consists of a mass of minute glass

bubbles; these bubbles do not usually, however, retain their globular

form, but are elongated in one direction through the movement of

the mass while it is still in a plastic state. The quantity of this

substance ejected is often enormous. We have seen to what a vast extent

it was thrown out from the crater of Krakatoa. During the year 1878,

masses of floating pumice were reported as existing in the vicinity of

the Solomon Isles, and covering the surface of the sea to such extent

that it took ships three days to force their way through them. Sometimes

this substance accumulates in such quantities along coasts that it is

difficult to determine the position of the shore within a mile or two,

as we may land and walk about on the great floating raft of pumice.

Recent deep-sea soundings, carried on in the Challenger and other

vessels, have shown that the bottom of the deepest portion of the ocean,

far away from the land, is covered with volcanic materials which have

been carried through the air or have floated on the surface of the

ocean.

Fragments of scoria or pumice may be thrown hundreds or thousands of

feet into the atmosphere, those that fall into the crater and are flung

up again being gradually reduced in size by friction. Thus it is related

by Mr. Poulett Scrope, who watched the Vesuvian eruption of 1822,

which lasted for nearly a month, that during the earlier stages of the

outburst fragments of enormous size were thrown out of the crater, but

by constant re-ejection these were gradually reduced in size, till

at last only the most impalpable dust issued from the vent. This dust

filled the atmosphere, producing in the city of Naples “a darkness that

might be felt.” So excessively finely divided was it, that it penetrated

into all drawers, boxes, and the most closely fastened receptacles,

filling them completely. The fragmentary materials ejected from

volcanoes are often given the name of cinders or ashes. These, however,

are terms of convenience only, and do not properly describe the volcanic

material.

Sometimes the passages of steam through a mass of molten glass produces

large quantities of a material resembling spun glass. Small particles of

this glass are carried into the air and leave behind them thin, glassy

filaments like a tail. At the volcano of Kilauea in Hawaii, this

substance, as previously stated, is abundantly produced, and is known

as ‘Pele’s Hair’--Pele being the name of the goddess of the mountain.

Birds’ nests are sometimes found composed of this beautiful material.

In recent years an artificial substance similar to this Pele’s hair

has been extensively manufactured by passing jets of steam through the

molten slag of iron-furnaces; it resembles cotton-wool, but is made up

of fine threads of glass, and is employed for the packing of boilers and

other purposes.

The lava itself, as left in huge deposits upon the surface, assumes

various forms, some crystalline, others glassy. The latter is usually

found in the condition known as obsidian, ordinarily black in color,

and containing few or no crystals. It is brittle, and splits into

sharp-edged or pointed fragments, which were used by primitive peoples

for arrow-heads, knives and other cutting implements. The ancient

Mexicans used bits of it for shaving purposes, it having an edge of

razor-like sharpness. They also used it as the cutting part of their

weapons of war.

CHAPTER XX.

The Active Volcanoes of the Earth.

It is not by any means an easy task to frame an estimate of the number

of volcanoes in the world. Volcanoes vary greatly in their dimensions,

from vast mountain masses, rising to a height of nearly 25,000 feet

above sea-level, to mere molehills. They likewise exhibit every possible

stage of development and decay: while some are in a state of chronic

active eruption, others are reduced to the condition of solfataras, or

vents emitting acid vapors, and others again have fallen into a more or

less complete state of ruin through the action of denuding forces.

NUMBER OF ACTIVE VOLCANOES

Even if we confine our attention to the larger volcanoes, which merit

the name of mountains, and such of these as we have reason to believe to

be in a still active condition, our difficulties will be diminished, but

not by any means removed. Volcanoes may sink into a dormant condition

that at times endures for hundreds or even thousands of years, and

then burst forth into a state of renewed activity; and it is quite

impossible, in many cases, to distinguish between the conditions of

dormancy and extinction.

We shall, however, probably be within the limits of truth in stating

that the number of great habitual volcanic vents upon the globe which

we have reason to believe are still in active condition, is somewhere

between 300 and 350. Most of these are marked by more or less

considerable mountains, composed of the materials ejected from them.

But if we include mountains which exhibit the external conical form,

crater-like hollows, and other features of volcanoes, yet concerning the

activity of which we have no record or tradition, the number will fall

little, if anything, short of 1,000.

The mountains composed of volcanic materials, but which have lost

through denudation the external form of volcanoes, are still more

numerous, and the smaller temporary openings which are usually

subordinate to the habitual vents that have been active during the

periods covered by history and tradition, must be numbered by thousands.

There are still feebler manifestations of the volcanic forces--such as

steam-jets, geysers, thermal and mineral waters, spouting saline and

muddy springs, and mud volcanoes--that may be reckoned by millions.

It is not improbable that these less powerful manifestations of the

volcanic forces to a great extent make up in number what they want in

individual energy; and the relief which they afford to the imprisoned

activities within the earth’s crust may be almost equal to that which

results from the occasional outbursts at the great habitual volcanic

vents.

In taking a general survey of the volcanic phenomena of the globe,

no facts come out more strikingly than that of the very unequal

distribution, both of the great volcanoes, and of the minor exhibitions

of subterranean energy.

Thus, on the whole of the continent of Europe, there is but one habitual

volcanic vent--that of Vesuvius--and this is situated upon the shores of

the Mediterranean. In the islands of that sea, however there are no

less than six volcanoes: namely, Stromboli, and Vulcano, in the Lipari

Islands; Etna, in Sicily; Graham’s Isle, a submarine volcano, off the

Sicilian coast; and Santorin and Nisyros, in the Aegean Sea.

The African continent is at present known to contain about ten active

volcanoes--four on the west coast, and six on the east coast, while

about ten other active volcanoes occur on islands close to the African

coasts. On the continent of Asia, more than twenty active volcanoes

are known or believed to exist, but no less than twelve of these are

situated in the peninsula of Kamchatka. No volcanoes are known to exist

in the Australian continent.

The American continent contains a greater number of volcanoes than

the continents of the Old World. There are twenty in North America,

twenty-five in Central America, and thirty-seven in South America. Thus,

taken altogether, there are about one hundred and seventeen volcanoes

situated on the great continental lands of the globe, while nearly twice

as many occur upon the islands scattered over the various oceans.

ASIATIC INLAND VOLCANOES

Upon examining further into the distribution of the continental

volcanoes, another very interesting fact presents itself. The volcanoes

are in almost every instance situated either close to the coasts of the

continent, or at no great distance from them. There are, indeed, only

two exceptions to this rule. In the great and almost wholly unexplored

table-land lying between Siberia and Tibet four volcanoes are said to

exist, and in the Chinese province of Manchuria several others. More

reliable information is, however, needed concerning these volcanoes.

It is a remarkable circumstance that all the oceanic islands which

are not coral-reefs are composed of volcanic rocks; and many of

these oceanic islands, as well as others lying near the shores of the

continents, contain active volcanoes.

Through the midst of the Atlantic Ocean runs a ridge, which, by the

soundings of the various exploring vessels sent out in recent years, has

been shown to divide the ocean longitudinally into two basins. Upon this

great ridge, and the spurs proceeding from it, rise numerous mountainous

masses, which constitute the well-known Atlantic islands and groups

of islands. All of these are of volcanic origin, and among them are

numerous active volcanoes. The Island of Jan Mayen contains an active

volcano, and Iceland contains thirteen, and not improbably more; the

Azores have six active volcanoes, the Canaries three; while about eight

volcanoes lie off the west coast of Africa. In the West Indies there are

six active volcanoes; and three submarine volcanoes have been recorded

within the limits of the Atlantic Ocean. Altogether, no less than forty

active volcanoes are situated upon the great submarine ridges which

traverse the Atlantic longitudinally.

But along the same line the number of extinct volcanoes is far greater,

and there are not wanting proofs that the volcanoes which are still

active are approaching the condition of extinction.

VOLCANOES OF THE PACIFIC

If the great medial chain of the Atlantic presents us with an example of

a chain of volcanic mountains verging on extinction, we have in the

line of islands separating the Pacific and Indian Oceans an example of a

similar range of volcanic vents which are in a condition of the

greatest activity. In the peninsula of Kamchatka there are twelve active

volcanoes, in the Aleutian Islands thirty-one, and in the peninsula

of Alaska three. The chain of the Kuriles contains at least ten active

volcanoes; the Japanese Islands and the islands to the south of Japan

twenty-five. The great group of islands lying to the south-east of the

Asiatic continent is at the present time the grandest focus of volcanic

activity upon the globe. No less than fifty active volcanoes occur here.

Farther south, the same chain is probably continued by the four active

volcanoes of New Guinea, one or more submarine volcanoes, and several

vents in New Britain, the Solomon Isles, and the New Hebrides, the three

active volcanoes of New Zealand, and possibly by Mount Erebus and Mount

Terror in the Antarctic region. Altogether, no less than 150 active

volcanoes exist in the chain of islands which stretch from Behring’s

Straits down to the Antarctic circle; and if we include the volcanoes

on Indian and Pacific Islands which appear to be situated on lines

branching from this particular band, we shall not be wrong in the

assertion that this great system of volcanic mountains includes at least

one half of the habitually active vents of the globe. In addition to

the active vents, there are here several hundred very perfect volcanic

cones, many of which appear to have recently become extinct, though some

of them may be merely dormant, biding their time.

A third series of volcanoes starts from the neighborhood of Behring’s

Straits, and stretches along the whole western coast of the American

continent. This is much less continuous, but nevertheless very

important, and contains, with its branches, nearly a hundred active

volcanoes. On the north this great band is almost united with the one

we have already described by the chain of the Aleutian and Alaska

volcanoes. In British Columbia about the parallel of 60 degrees N. there

exist a number of volcanic mountains, one of which, Mount St. Elias, is

believed to be 18,000 feet in height. Farther south, in the territory of

the United States, a number of grand volcanic mountains exist, some of

which are probably still active, for geysers and other manifestations of

volcanic activity abound. From the southern extremity of the peninsula

of California an almost continuous chain of volcanoes stretches through

Mexico and Guatemala, and from this part of the volcanic band a branch

is given off which passes through the West Indies, and contains the

volcanoes which have so recently given evidence of their vital activity.

In South America the line is continued by the active volcanoes of

Ecuador, Bolivia and Chile, but at many intermediate points in the chain

of the Andes extinct volcanoes occur, which to a great extent fill up

the gaps in the series. A small offshoot to the westward passes through

the Galapagos Islands. The great band of volcanoes which stretches

through the American continent is second only in importance, and in the

activity of its vents, to the band which divides the Pacific from the

Indian Ocean.

The third volcanic band of the globe is that, already spoken of,

which traverses the Atlantic Ocean from north to south. This series of

volcanic mountains is much more broken and interrupted than the other

two, and a greater proportion of its vents are extinct. It attained its

condition of maximum activity during the distant period of the Miocene,

and now appears to be passing into a state of gradual extinction.

Beginning in the north with the volcanic rocks of Greenland and Bear

Island, we pass southwards, by way of Jan Mayen, Iceland and the Faroe

Islands, to the Hebrides and the north of Ireland. Thence, by way of

the Azores, the Canaries and the Cape de Verde Islands, with some active

vents, we pass to the ruined volcanoes of St. Paul, Fernando de Noronha,

Ascension, St. Helena, Trinidad and Tristan da Cunha. From this great

Atlantic band two branches proceed to the eastward, one through Central

Europe, where all the vents are now extinct, and the other through the

Mediterranean to Asia Minor, the great majority of the volcanoes along

the latter line being now extinct, though a few are still active. The

volcanoes on the eastern coast of Africa may be regarded as situated on

another branch from this Atlantic volcanic band. The number of active

volcanoes on this Atlantic band and its branches, exclusive of those in

the West Indies, does not exceed fifty.

THIAN SHAN AND HAWAIIAN VOLCANOES

From what has been said, it will be seen that the volcanoes of the globe

not only usually assume a linear arrangement, but nearly the whole of

them can be shown to be thrown up along three well-marked bands and the

branches proceeding from them. The first and most important of these

bands is nearly 10,000 miles in length, and with its branches contains

more than 150 active volcanoes; the second is 8,000 miles in length, and

includes about 100 active volcanoes; the third is much more broken and

interrupted, extends to a length of nearly 1,000 miles, and contains

about 50 active vents. The volcanoes of the eastern coast of Africa,

with Mauritius, Bourbon, Rodriguez, and the vents along the line of the

Red Sea, may be regarded as forming a fourth and subordinate band.

Thus we see that the surface of the globe is covered by a network of

volcanic bands, all of which traverse it in sinuous lines with a general

north-and-south direction, giving off branches which often run for

hundreds of miles, and sometimes appear to form a connection between the

great bands.

To this rule of the linear arrangement of the volcanic vents of the

globe, and their accumulation along certain well-marked bands, there are

two very striking exceptions, which we must now proceed to notice.

In the very centre of the continent formed by Europe and Asia, the

largest unbroken land-mass of the globe, there rises from the great

central plateau the remarkable volcanoes of the Thian Shan Range. The

existence of these volcanoes, of which only obscure traditional accounts

had reached Europe before the year 1858, appears to be completely

established by the researches of recent Russian and Swedish travelers.

Three volcanic vents appear to exist in this region, and other volcanic

phenomena have been stated to occur in the great plateau of Central

Asia, but the existence of the latter appears to rest on very doubtful

evidence. The only accounts which we have of the eruptions of these

Thian Shan volcanoes are contained in Chinese histories and treatises on

geography.

The second exceptionally situated volcanic group is that of the Hawaiian

Islands. While the Thian Shan volcanoes rise in the centre of the

largest unbroken land-mass, and stand on the edge of the loftiest and

greatest plateau in the world, the volcanoes of the Hawaiian Islands

rise in the northern centre of the largest ocean and from almost the

greatest depths in that ocean. All round the Hawaiian Islands the

sea has a depth of from 2,000 to 3,000 fathoms, and the island-group

culminates in several volcanic cones, which rise to the height of nearly

14,000 feet above the sea-level. The volcanoes of the Hawaiian Islands

are unsurpassed in height and bulk by those of any other part of the

globe.

With the exception of the two isolated groups of the Thian Shan and

the Hawaiian Islands, nearly all the active volcanoes of the globe are

situated near the limits which separate the great land-and-water-masses

of the globe--that is to say, they occur either on the parts of

continents not far removed from their coast-lines, or on islands in

the ocean not very far distant from the shores. The fact of the general

proximity of volcanoes to the sea is one which has frequently been

pointed out by geographers, and may now be regarded as being thoroughly

established.

VOLCANOES PARALLEL TO MOUNTAIN CHAINS

Many of the grandest mountain-chains have bands of volcanoes

lying parallel to them. This is strikingly exhibited by the great

mountain-masses which lie on the western side of the American continent.

The Rocky Mountains and the Andes consist of folded and crumpled masses

of altered strata which, by the action of denuding forces, have been

carved into series of ridges and summits. At many points, however, along

the sides of these great chains we find that fissures have been opened

and lines of volcanoes formed, from which enormous quantities of lava

have flowed and covered great tracts of country.

This is especially marked in the Snake River plain of Idaho, in the

western United States. In this, and the adjoining regions of Oregon and

Washington, an enormous tract of country has been overflowed by lava in

a late geological period, the surface covered being estimated to have a

larger area than France and Great Britain combined. The Snake River cuts

through it in a series of picturesque gorges and rapids, enabling us to

estimate its thickness, which is considered to average 4000 feet. Looked

at from any point on its surface, one of these lava-plains appears as a

vast level surface, like that of a lake bottom. This uniformity has been

produced either by the lava rolling over a plain or lake bottom, or by

the complete effacement of an original, undulating contour of the ground

under hundreds or thousands of feet of lava in successive sheets.

The lava, rolling up to the base of the mountains, has followed

the sinuosities of their margin, as the waters of a lake follow its

promontories and bays. Similar conditions exist along the Sierra Nevada

range of California, and to some extent placer mining has gone on under

immense beds of lava, by a process of tunneling beneath the volcanic

rock.

In some localities the volcanoes are of such height and dimensions as

to overlook and dwarf the mountain-ranges by the side of which they lie.

Some of the volcanoes lying parallel to the great American axis appear

to be quite extinct, while others are in full activity. In the Eastern

continent we find still more striking examples of parallelism between

great mountain-chains and the lands along which volcanic activity is

exhibited--volcanoes, active or extinct, following the line of the great

east and west chains which extend through southern Europe and Asia.

There are some other volcanic bands which exhibit a similar parallelism

with mountain chains; but, on the other hand, there are volcanoes

between which and the nearest mountain-axis no such connection can be

traced.

AREAS OF UPHEAVAL AND SUBSIDENCE

There is one other fact concerning the mode of distribution of volcanoes

upon the surface of the globe, to which we must allude. By a study

of the evidences presented by coral-reefs, raised beaches, submerged

forests, and other phenomena of a similar kind, it can be shown that

certain wide areas of the land and of the ocean-floor are at the present

time in a state of subsidence, while other equally large areas are

being upheaved. And the observations of the geologist prove that similar

upward and downward movements of portions of the earth’s crust have been

going on through all geological times.

Now, as Mr. Darwin has so well shown in his work on “Coral Reefs,” if we

trace upon a map the areas of the earth’s surface which are undergoing

upheaval and subsidence respectively, we shall find that nearly all the

active volcanoes of the globe are situated upon rising areas and that

volcanic phenomena are conspicuously absent from those parts of the

earth’s crust which can be proved at the present day to be undergoing

depression.

The remarkable linear arrangement of volcanic vents has a significance

that is well worthy of fuller consideration. There are facts known which

point to the cause of this state of affairs. It is not uncommon for

small cones of scoriae to be seen following lines on the flanks or at

the base of a great volcanic mountain. These are undoubtedly lines of

fissure, caused by the subterranean forces. In fact, such fissures have

been seen opening on the sides of Mount Etna, in whose bottom could

be seen the glowing lava. Along these fissures, in a few days, scoriae

cones appeared; on one occasion no less than thirty-six in number.

It is believed by geologists that the linear systems of volcanoes are

ranged along similar lines of fissure in the earth’s crust--enormous

breaks, extending for thousands of miles, and the result of internal

energies acting through vast periods of time. Along these immense

fissures in the earth’s rock-crust there appear, in place of small

scoriae cones, great volcanoes, built up through the ages by a series of

powerful eruptions, and only ceasing to spout fire themselves when the

portion of the great crack upon which they lie is closed. The greatest

of these fissures is that along the vast sinuous band of volcanoes

extending from near the Arctic circle at Behring’s Straits to the

Antarctic circle at South Victoria Land, not far from half round the

earth. It doubtless marks the line of mighty forces which have been

active for millions of years.

CHAPTER XXI.

The Famous Vesuvius and the Destruction of Pompeii.

The famous volcano of southern Italy named Vesuvius, which is now so

constantly in eruption, was described by the ancients as a cone-shaped

mountain with a flat top, on which was a deep circular valley filled

with vines and grass, and surrounded by high precipices. A large

population lived on the sides of the mountain, which was covered with

beautiful woods, and there were fine flourishing cities at its foot. So

little was the terrible nature of the valley on the top understood, that

in A. D. 72, Spartacus, a rebellious Roman gladiator, encamped there

with some thousands of fighting men, and the Roman soldiers were let

down the precipices in order to surprise and capture them.

There had been earthquakes around the mountain, and one of the cities

had been nearly destroyed; but no one was prepared for what occurred

seven years after the defeat of Spartacus. Suddenly, in the year 79

A. D., a terrific rush of smoke, steam, and fire belched from the

mountain’s summit; one side of the valley in which Spartacus had

encamped was blown off, and its rocks, with vast quantities of ashes,

burning stones, and sand, were ejected far into the sky. They then

spread out like a vast pall, and fell far and wide. For eight days

and nights this went on, and the enormous quantity of steam sent up,

together with the deluge of rain that fell, produced torrents on the

mountain-side, which, carrying onward the fallen ashes, overwhelmed

everything in their way. Sulphurous vapors filled the air and violent

tremblings of the earth were constant.

A city six miles off was speedily rendered uninhabitable, and was

destroyed by the falling stones; but two others--Herculaneum and

Pompeii--which already had suffered from the down-pour of ashes, were

gradually filled with a flood of water, sand, and ashes, which came down

the side of the volcano, and covering them entirely.

BURIED CITIES EXCAVATED.

The difference in ease of excavation is due to the following

circumstance. Herculaneum being several miles nearer the crater,

was buried in a far more consistent substance, seemingly composed of

volcanic ashes cemented by mud; Pompeii, on the contrary, was

buried only in ashes and loose stones. The casts of statues found in

Herculaneum show the plastic character of the material that fell there,

which time has hardened to rock-like consistency.

These statues represented Hercules and Cleopatra, and the theatre proved

to be that of the long-lost city of Herculaneum. The site of Pompeii was

not discovered until forty years afterward, but work there proved far

easier than at Herculaneum, and more progress was made in bringing it

back to the light of day.

The less solid covering of Pompeii has greatly facilitated the work of

excavation, and a great part of the city has been laid bare. Many of its

public buildings and private residences are now visible, and some whole

streets have been cleared, while a multitude of interesting relics have

been found. Among those are casts of many of the inhabitants, obtained

by pouring liquid plaster into the ash moulds that remained of them.

We see them to-day in the attitude and with the expression of agony and

horror with which death met them more than eighteen centuries ago.

In succeeding eruptions much lava was poured out; and in A. D. 472,

ashes were cast over a great part of Europe, so that much fear was

caused at Constantinople. The buried cities were more and more covered

up, and it was not until about A. D. 1700 that, as above stated, the

city of Herculaneum was discovered, the peasants of the vicinity being

in the habit of extracting marble from its ruins. They had also, in the

course of years, found many statues. In consequence, an excavation was

ordered by Charles III, the earliest result being the discovery of the

theatre, with the statues above named. The work of excavation,

however, has not progressed far in this city, on account of its extreme

difficulty, though various excellent specimens of art-work have been

discovered, including the finest examples of mural painting extant from

antiquity. The library was also discovered, 1803 papyri being found.

Though these had been charred to cinder, and were very difficult to

unroll and decipher, over 300 of them have been read.

PLINY’S CELEBRATED DESCRIPTION

Pliny the Younger, to whom we are indebted for the only contemporary

account of the great eruption under consideration, was at the time of

its occurrence resident with his mother at Misenum, where the Roman

fleet lay, under the command of his uncle, the great author of the

“Historia Naturalis”. His account, contained in two letters to Tacitus

(lib. vi. 16, 20), is not so much a narrative of the eruption, as a

record of his uncle’s singular death, yet it is of great interest as

yielding the impressions of an observer. The translation which follows

is adopted from the very free version of Melmoth, except in one or two

places, where it differs much from the ordinary text. The letters are

given entire, though some parts are rather specimens of style than good

examples of description.

“Your request that I should send an account of my uncle’s death, in

order to transmit a more exact relation of it to posterity, deserves my

acknowledgments; for if this accident shall be celebrated by your pen,

the glory of it, I am assured, will be rendered forever illustrious.

And, notwithstanding he perished by a misfortune which, as it involved

at the same time a most beautiful country in ruins, and destroyed so

many populous cities, seems to promise him an everlasting remembrance;

notwithstanding he has himself composed many and lasting works; yet I

am persuaded the mention of him in your immortal works will greatly

contribute to eternize his name. Happy I esteem those to be, whom

Providence has distinguished with the abilities either of doing such

actions as are worthy of being related, or of relating them in a manner

worthy of being read; but doubly happy are they who are blessed with

both these talents; in the number of which my uncle, as his own writings

and your history will prove, may justly be ranked. It is with extreme

willingness, therefore, that I execute your commands; and should,

indeed, have claimed the task if you had not enjoined it.

“He was at that time with the fleet under his command at Misenum. On

the 24th of August, about one in the afternoon, my mother desired him to

observe a cloud which appeared of a very unusual size and shape. He had

just returned from taking the benefit of the sun, and, after bathing

himself in cold water, and taking a slight repast, had retired to his

study. He immediately arose, and went out upon an eminence, from whence

he might more distinctly view this very uncommon appearance. It was not

at that distance discernible from what mountain the cloud issued, but it

was found afterward to ascend from Mount Vesuvius. I cannot give a more

exact description of its figure than by comparing it to that of a pine

tree, for it shot up to a great height in the form of a trunk, which

extended itself at the top into a sort of branches; occasioned, I

imagine, either by a sudden gust of air that impelled it, the force

of which decreased as it advanced upwards, or the cloud itself being

pressed back again by its own weight, and expanding in this manner: it

appeared sometimes bright, and sometimes dark and spotted, as it was

more or less impregnated with earth and cinders.

“This extraordinary phenomenon excited my uncle’s philosophical

curiosity to take a nearer view of it. He ordered a light vessel to be

got ready, and gave me the liberty, if I thought proper, to attend him.

I rather chose to continue my studies, for, as it happened, he had given

me an employment of that kind. As he was passing out of the house he

received dispatches: the marines at Retina, terrified at the imminent

peril (for the place lay beneath the mountain, and there was no retreat

but by ships), entreated his aid in this extremity. He accordingly

changed his first design, and what he began with a philosophical he

pursued with an heroical turn of mind.”

THE VOYAGE TO STABIAE

“He ordered the galleys to put to sea, and went himself on board with

an intention of assisting not only Retina but many other places, for the

population is thick on that beautiful coast. When hastening to the place

from whence others fled with the utmost terror, he steered a direct

course to the point of danger, and with so much calmness and presence of

mind, as to be able to make and dictate his observations upon the motion

and figure of that dreadful scene. He was now so nigh the mountain that

the cinders, which grew thicker and hotter the nearer he approached,

fell into the ships, together with pumice-stones, and black pieces of

burning rock; they were in danger of not only being left aground by the

sudden retreat of the sea, but also from the vast fragments which rolled

down from the mountain, and obstructed all the shore.

“Here he stopped to consider whether he should return back again; to

which the pilot advised him. ‘Fortune,’ said he, ‘favors the brave;

carry me to Pomponianus.’ Pomponianus was then at Stabiae, separated by

a gulf, which the sea, after several insensible windings, forms upon

the shore. He (Pomponianus) had already sent his baggage on board; for

though he was not at that time in actual danger, yet being within view

of it, and indeed extremely near, if it should in the least increase, he

was determined to put to sea as soon as the wind should change. It was

favorable, however, for carrying my uncle to Pomponianus, whom he

found in the greatest consternation. He embraced him with tenderness,

encouraging and exhorting him to keep up his spirits; and the more to

dissipate his fears he ordered, with an air of unconcern, the baths

to be got ready; when, after having bathed, he sat down to supper with

great cheerfulness, or at least (what is equally heroic) with all the

appearance of it.

“In the meantime, the eruption from Mount Vesuvius flamed out in several

places with much violence, which the darkness of the night contributed

to render still more visible and dreadful. But my uncle, in order to

soothe the apprehensions of his friend, assured him it was only the

burning of the villages, which the country people had abandoned to the

flames; after this he retired to rest, and it was most certain he was so

little discomposed as to fall into a deep sleep; for, being pretty fat,

and breathing hard, those who attended without actually heard him snore.

The court which led to his apartment being now almost filled with stones

and ashes, if he had continued there any longer it would have been

impossible for him to have made his way out; it was thought proper,

therefore, to awaken him. He got up and went to Pomponianus and the rest

of his company, who were not unconcerned enough to think of going to

bed. They consulted together whether it would be most prudent to trust

to the houses, which now shook from side to side with frequent and

violent concussions; or to fly to the open fields, where the calcined

stone and cinders, though light indeed, yet fell in large showers and

threatened destruction. In this distress they resolved for the fields as

the less dangerous situation of the two--a resolution which, while

the rest of the company were hurried into it by their fears, my uncle

embraced upon cool and deliberate consideration.

DEATH OF PLINY THE ELDER

“They went out, then, having pillows tied upon their heads with napkins;

and this was their whole defence against the storm of stones that fell

around them. It was now day everywhere else, but there a deeper darkness

prevailed than in the most obscure night; which, however, was in some

degree dissipated by torches and other lights of various kinds. They

thought proper to go down further upon the shore, to observe if they

might safely put out to sea; but they found that the waves still ran

extremely high and boisterous. There my uncle, having drunk a draught or

two of cold water, threw himself down upon a cloth which was spread for

him, when immediately the flames, and a strong smell of sulphur which

was the forerunner of them, dispersed the rest of the company, and

obliged him to rise. He raised himself up with the assistance of two of

his servants, and instantly fell down dead, suffocated, as I conjecture,

by some gross and noxious vapor, having always had weak lungs, and being

frequently subject to a difficulty of breathing.

“As soon as it was light again, which was not till the third day after

this melancholy accident, his body was found entire, and without any

marks of violence upon it, exactly in the same posture as that in which

he fell, and looking more like a man asleep than dead. During all this

time my mother and I were at Misenum. But this has no connection with

your history, as your inquiry went no farther than concerning my uncle’s

death; with that, therefore, I will put an end to my letter. Suffer me

only to add, that I have faithfully related to you what I was either

an eye-witness of myself, or received immediately after the accident

happened, and before there was any time to vary the truth. You will

choose out of this narrative such circumstances as shall be most

suitable to your purpose; for there is a great difference between what

is proper for a letter and a history: between writing to a friend and

writing to the public. Farewell.”

In this account, which was drawn up some years after the event, from

the recollections of a student eighteen years old, we recognize the

continual earthquakes; the agitated sea with its uplifted bed; the

flames and vapors of an ordinary eruption, probably attended by lava as

well as ashes. But it seems likely that the author’s memory, or rather

the information communicated to him regarding the closing scene of

Pliny’s life, was defective. Flames and sulphurous vapors could hardly

be actually present at Stabiae, ten miles from the centre of the

eruption.

That lava flowed at all from Vesuvius on this occasion has been usually

denied; chiefly because at Pompeii and Herculaneum the causes of

destruction were different--ashes overwhelmed the former, mud concreted

over the latter. We observe, indeed, phenomena on the shore near Torre

del Greco which seem to require the belief that currents of lava had

been solidified there at some period before the construction of certain

walls and floors, and other works of Roman date. In the Oxford Museum,

among the specimens of lava to which the dates are assigned, is one

referred to A. D. 79, but there is no mode of proving it to have

belonged to the eruption of that date.

PLINY’S SECOND LETTER

A second letter from Pliny to Tacitus (Epist. 20) was required to

satisfy the curiosity of that historian; especially as regards the

events which happened under the eyes of his friend. Here it is according

to Melmoth:

“The letter which, in compliance with your request, I wrote to you

concerning the death of my uncle, has raised, it seems, your curiosity

to know what terrors and danger attended me while I continued at

Misenum: for there, I think, the account in my former letter broke off.

‘Though my shocked soul recoils, my tongue shall tell.’

“My uncle having left us, I pursued the studies which prevented my going

with him till it was time to bathe. After which I went to supper, and

from thence to bed, where my sleep was greatly broken and disturbed.

There had been, for many days before, some shocks of an earthquake,

which the less surprised us as they are extremely frequent in Campania;

but they were so particularly violent that night, that they not only

shook everything about us, but seemed, indeed, to threaten total

destruction. My mother flew to my chamber, where she found me rising

in order to awaken her. We went out into a small court belonging to the

house, which separated the sea from the buildings. As I was at that time

but eighteen years of age, I know not whether I should call my behavior,

in this dangerous juncture, courage or rashness; but I took up Livy, and

amused myself with turning over that author, and even making extracts

from him, as if all about me had been in full security. While we were

in this posture, a friend of my uncle’s, who was just come from Spain to

pay him a visit, joined us; and observing me sitting with my mother with

a book in my hand, greatly condemned her calmness at the same time that

he reproved me for my careless security. Nevertheless, I still went on

with my author.

“Though it was now morning, the light was exceedingly faint and languid;

the buildings all around us tottered; and, though we stood upon open

ground, yet as the place was narrow and confined, there was no remaining

there without certain and great danger: we therefore resolved to quit

the town. The people followed us in the utmost consternation, and, as to

a mind distracted with terror every suggestion seems more prudent than

its own, pressed in great crowds about us in our way out.

“Being got to a convenient distance from the houses, we stood still, in

the midst of a most dangerous and dreadful scene. The chariots which

we had ordered to be drawn out were so agitated backwards and forwards,

though upon the most level ground, that we could not keep them steady,

even by supporting them with large stones. The sea seemed to roll back

upon itself, and to be driven from its banks by the convulsive motion

of the earth; it is certain at least that the shore was considerably

enlarged, and many sea animals were left upon it. On the other side a

black and dreadful cloud, bursting with an igneous serpentine vapor,

darted out a long train of fire, resembling flashes of lightning, but

much larger.

FEAR VERSUS COMPOSURE

“Upon this the Spanish friend whom I have mentioned, addressed himself

to my mother and me with great warmth and earnestness; ‘If your brother

and your uncle,’ said he, ‘is safe, he certainly wishes you to be so

too; but if he has perished, it was his desire, no doubt, that you might

both survive him: why therefore do you delay your escape a moment?’ We

could never think of our own safety, we said, while we were uncertain

of his. Hereupon our friend left us, and withdrew with the utmost

precipitation. Soon afterward, the cloud seemed to descend, and cover

the whole ocean; as it certainly did the island of Capreae, and the

promontory of Misenum. My mother strongly conjured me to make my escape

at any rate, which, as I was young, I might easily do; as for herself,

she said, her age and corpulency rendered all attempts of that sort

impossible. However, she would willingly meet death, if she could have

the satisfaction of seeing that she was not the occasion of mine. But I

absolutely refused to leave her, and taking her by the hand, I led her

on; she complied with great reluctance, and not without many reproaches

to herself for retarding my flight.

“The ashes now began to fall upon us, though in no great quantity. I

turned my head and observed behind us a thick smoke, which came rolling

after us like a torrent. I proposed, while we yet had any light, to turn

out of the high road lest she should be pressed to death in the dark by

the crowd that followed us. We had scarce stepped out of the path when

darkness overspread us, not like that of a cloudy night, or when there

is no moon, but of a room when it is all shut up and all the lights

are extinct. Nothing then was to be heard but the shrieks of women,

the screams of children and the cries of men; some calling for their

children, others for their parents, others for their husbands, and only

distinguishing each other by their voices; one lamenting his own fate,

another that of his family; some wishing to die from the very fear

of dying; some lifting their hands to the gods; but the greater part

imagining that the last and eternal night was come, which was to destroy

the gods and the world together. Among them were some who augmented the

real terrors by imaginary ones, and made the frighted multitude believe

that Misenum was actually in flames.

“At length a glimmering light appeared, which we imagined to be rather

the forerunner of an approaching burst of flames, as in truth it was,

than the return of day. However, the fire fell at distance from us; then

again we were immersed in thick darkness, and a heavy shower of ashes

rained upon us, which we were obliged every now and then to shake off,

otherwise we should have been crushed and buried in the heap.

“I might boast that, during all this scene of horror, not a sigh or

expression of fear escaped me, had not my support been founded in that

miserable, though strong, consolation that all mankind were involved in

the same calamity, and that I imagined I was perishing with the world

itself! At last this dreadful darkness was dissipated by degrees, like a

cloud of smoke; the real day returned, and soon the sun appeared, though

very faintly, and as when an eclipse is coming on. Every object that

presented itself to our eyes (which were extremely weakened) seemed

changed, being covered over with white ashes, as with a deep snow. We

returned to Misenum, where we refreshed ourselves as well as we could,

and passed an anxious night between hope and fear, for the earthquake

still continued, while several greatly excited people ran up and

down, heightening their own and their friends’ calamities by terrible

predictions. However, my mother and I, notwithstanding the danger we had

passed and that which still threatened us, had no thoughts of leaving

the place till we should receive some account from my uncle.

“And now you will read this narrative without any view of inserting it

in your history, of which it is by no means worthy; and, indeed, you

must impute it to your own request if it shall not even deserve the

trouble of a letter. Farewell!”

DION CASSIUS ON THE ERUPTION

The story told by Pliny is the only one upon which we can rely. Dion

Cassius, the historian, who wrote more than a century later, does not

hesitate to use his imagination, telling us that Pompeii was buried

under showers of ashes “while all the people were sitting in the

theatre.” This statement has been effectively made use of by Bulwer, in

his “Last Days of Pompeii.” In this he pictures for us a gladiatorial

combat in the arena, with thousands of deeply interested spectators

occupying the surrounding seats. The novelist works his story up to a

thrilling climax in which the volcano plays a leading part.

This is all very well as a vivid piece of fiction, but it does not

accord with fact, since Dion Cassius was undoubtedly incorrect in his

statement. We now know from the evidence furnished by the excavations

that none of the people were destroyed in the theatres, and, indeed,

that there were very few who did not escape from both cities. It is

very likely that many of them returned and dug down for the most valued

treasures in their buried habitations. Dion Cassius may have obtained

the material for his accounts from the traditions of the descendants of

survivors, and if so he shows how terrible must have been the impression

made upon their minds. He assures us that during the eruption a

multitude of men of superhuman nature appeared, sometimes on the

mountain and sometimes in the environs, that stones and smoke were

thrown out, the sun was hidden, and then the giants seemed to rise

again, while the sounds of trumpets were heard.

LAKE AVERNUS

Not far from Vesuvius lay the famous Lake Avernus, whose name was long

a popular synonym for the infernal regions. The lake is harmless to-day,

but its reputation indicates that it was not always so. There is every

reason to believe that it hides the outlet of an extinct volcano, and

that long after the volcano ceased to be active it emitted gases as

fatal to animal life as those suffocating vapors which annihilated all

the cattle on the Island of Lancerote, in the Canaries, in the year

1730. Its name signifies “birdless,” indicating that its ascending

vapors were fatal to all birds that attempted to fly above its surface.

In the superstition of the Middle Ages Vesuvius assumed the character

which had before been given to Avernus, and was regarded as the mouth of

hell. Cardinal Damiano, in a letter to Pope Nicholas II., written about

the year 1060 tells the story of how a priest, who had left his mother

ill at Beneventum, went on his homeward way to Naples past the crater of

Vesuvius, and heard issuing therefrom the voice of his mother in great

agony. He afterward found that her death coincided exactly with the time

at which he had heard her voice.

A trip to the summit of Vesuvius is one of the principal attractions

for strangers who are visiting Naples. There is a fascination about that

awful slayer of cities which few can resist, and no less attractive

is the city of Pompeii, now largely laid bare after being buried for

eighteen centuries. We are indebted to Henry Haynie for the following

interesting description: “Once seen, it will never be forgotten. It is

full of suggestions. It kindles emotions that are worth the kindling,

and brings on dreams that are worth the dreaming. Of the three places

overwhelmed, Herculaneum, Pompeii and Stabiae, the last scarcely repays

excavation in one sense, and the first in another; but to watch the

diggers at Pompeii is fascinating, even when there is no reasonable

expectation of a find. Herculaneum was buried with lava, or rather with

tufa, and it is so very hard that the expense of uncovering of only a

small part of that city has been very great.

HOW POMPEII IMPRESSES ITS VISITORS

“Pompeii was smothered in ashes, however, and most of it is uncovered

now. But while there is much that is fascinating, and all of it is

instructive, there is nothing grand or awe-inspiring in the ruins of

Pompeii. No visitor stands breathless as in the great hall of Karnak or

in the once dreadful Coliseum at Rome, or dreams with sensuous delight

as before the Jasmine Court at Agra.

“The weirdness of the scene possesses us as a haunted chamber might. We

have before us the narrow lanes, paved with tufa, in which Roman wagon

wheels have worn deep ruts. We cross streets on stepping-stones which

sandaled feet ages ago polished. We see the wine shops with empty jars,

counters stained with liquor, stone mills where the wheat was ground,

and the very ovens in which bread was baked more than eighteen centuries

ago. ‘Welcome’ is offered us at one silent, broken doorway; at another

we are warned to ‘Beware of the dog!’ The painted figures,--some of

them so artistic and rich in colors that pictures of them are

disbelieved,--the mosaic pavements, the empty fountains, the altars and

household gods, the marble pillars and the small gardens are there just

as the owners left them. Some of the walls are scribbled over by the

small boys of Pompeii in strange characters which mock modern erudition.

In places we read the advertisements of gladiatorial shows, never to

come off, the names of candidates for legislative office who were never

to sit. There is nothing like this elsewhere.

“The value of Pompeii to those classic students who would understand,

not the speech only, but the life and the every-day habits, of the

ancient world, is too high for reckoning. Its inestimable evidence may

be seen in the fact that any high-school boy can draw the plan of a

Roman house, while ripest scholars hesitate on the very threshold of

a Greek dwelling. This is because no Hellenic Pompeii has yet been

discovered, but thanks to the silent city close to the beautiful Bay of

Naples, the Latin house is known from ostium to porticus, from the front

door to the back garden wall.

STREETS AND HOUSES OF POMPEII

“The streets of Pompeii must have had a charm unapproached by those

of any city now in existence. The stores, indeed, were wretched little

dens. Two or three of them commonly occupied the front of a house on

either side of the entrance, the ostium; but when the door lay open, as

was usually the case, a passerby could look into the atrium, prettily

decorated and hung with rich stuffs. The sunshine entered through an

aperture in the roof, and shone on the waters of the impluvium, the

mosaic floor, the altar of the household gods and the flowers around the

fountain.

“As the life of the Pompeiians was all outdoors, their pretty homes

stood open always. There was indeed a curtain betwixt the atrium and the

peristyle, but it was drawn only when the master gave a banquet. Thus a

wayfarer in the street could see, beyond the hall described and its

busy servants, the white columns of the peristyle, with creepers trained

about them, flowers all around, and jets of water playing through pipes

which are still in place. In many cases the garden itself could be

observed between the pillars of the further gallery, and rich paintings

on the wall beyond that.

“But how far removed those little palaces of Pompeii were from our

notion of well-being is scarcely to be understood by one who has not

seen them. It is a question strange in all points of view where the

family slept in the houses, nearly all of which had no second story. In

the most graceful villas the three to five sleeping chambers round the

atrium and four round the peristyle were rather ornamental cupboards

than aught else. One did not differ from another, and if these were

devoted to the household the slaves, male and female, must have slept

on the floor outside. The master, his family and his guest used these

small, dark rooms, which were apparently without such common luxuries

as we expect in the humblest home. All their furniture could hardly have

been more than a bed and a footstool; but it should be remembered

that the public bath was a daily amusement. The kitchen of each villa

certainly was not furnished with such ingenuity, expense or thought as

the stories of Roman gormandising would have led us to expect. In the

house of the Aedile--so called from the fact that ‘Pansam Aed.’ is

inscribed in red characters by the doorway--the cook seems to have been

employed in frying eggs at the moment when increasing danger put him to

flight. His range, four partitions of brick, was very small; a knife,

a strainer, a pan lay by the fire just as they fell from the slave’s

hand.”

VALUE OF THE DISCOVERY OF POMPEII

This description strongly presents to us the principal value of the

discovery of Pompeii. Interesting as are the numerous works of art found

in its habitations, and important as is their bearing upon some branches

of the art of the ancient world, this cannot compare in interest with

the flood of light which is here thrown on ancient life in all its

details, enabling us to picture to ourselves the manners and habits of

life of a cultivated and flourishing population at the beginning of the

Christian era, to an extent which no amount of study of ancient history

could yield.

Looking upon the work of the volcano as essentially destructive, as

we naturally do, we have here a valuable example of its power as a

preservative agent; and it is certainly singular that it is to a

volcano we owe much of what we know concerning the cities, dwellings and

domestic life of the people of the Roman Empire.

It would be very fortunate for students of antiquity if similar

disasters had happened to cities in other ancient civilized lands,

however unfortunate it might have been to their inhabitants. But

doubtless we are better off without knowledge gained from ruins thus

produced.

CHAPTER XXII.

Eruptions of Vesuvius, Etna and Stromboli.

Mount Vesuvius is of especial interest as being the only active volcano

on the continent of Europe--all others of that region being on the

islands of the Mediterranean--and for the famous ancient eruption

described in the last chapter. Before this it had borne the reputation

of being extinct, but since then it has frequently shown that its fires

have not burned out, and has on several occasions given a vigorous

display of its powers.

During the fifteen hundred years succeeding the destructive event

described eruptions were of occasional occurrence, though of no great

magnitude. But throughout the long intervals when Vesuvius was at rest

it was noted that Etna and Ischia were more or less disturbed.

THE BIRTH OF MONTE NUOVO

In 1538 a startling evidence was given that there was no decline of

energy in the volcanic system of Southern Italy. This was the sudden

birth of the mountain still known as Monte Nuovo, or New Mountain,

which was thrown up in the Campania near Avernus, on the spot formerly

occupied by the Lucrine Lake.

For about two years prior to this event the district had been disturbed

by earthquakes, which on September 27 and 28, 1538, became almost

continuous. The low shore was slightly elevated, so that the sea

retreated, leaving bare a strip about two hundred feet in width. The

surface cracked, steam escaped, and at last, early on the morning of the

29th, a greater rent was made, from which were vomited furiously “smoke,

fire, stones and mud composed of ashes, making at the time of its

opening a noise like the loudest thunder.”

The ejected material in less than twelve hours built the hill which has

lasted substantially in the same form to our day. It is a noteworthy

fact that since the formation of Monte Nuovo there has been no volcanic

disturbance in any part of the Neapolitan district except in Vesuvius,

which for five centuries previous had remained largely at rest.

LAVA FROM VESUVIUS

The first recognised appearance of lava in the eruptions of Vesuvius was

in the violent eruption of 1036. This was succeeded at intervals by five

other outbreaks, none of them of great energy. After 1500 the crater

became completely quiet, the whole mountain in time being grown over

with luxuriant vegetation, while by the next century the interior of the

crater became green with shrubbery, indicating that no injurious gases

were escaping.

This was sleep, not death. In 1631 the awakening came in an eruption of

terrible violence. Almost in a moment the green mantle of woodland and

shrubbery was torn away and death and destruction left where peace and

safety had seemed assured.

Seven streams of lava poured from the crater and swept rapidly down the

mountain side, leaving ruin along their paths. Resina, Granasello and

Torre del Greco, three villages that had grown up during the period

of quiescence, were more or less overwhelmed by the molten lava. Great

torrents of hot water also poured out, adding to the work of desolation.

It was estimated that eighteen thousand of the inhabitants were killed.

What made the horror all the greater was a frightful error of judgment,

similar to that of the Governor of Martinique at St. Pierre. The

Governor of Torre del Greco had refused to be warned in time, and

prevented the people from making their escape until it was too late.

Not until the lava had actually reached the walls was the order for

departure given. Before the order could be acted upon the molten streams

burst through the walls into the crowded streets, and overwhelmed the

vast majority of the inhabitants.

In this violent paroxysm the whole top of the mountain is said to have

been swept away, the new crater which took the place of the old one

being greatly lowered. From that date Vesuvius has never been at rest

for any long interval, and eruptions of some degree of violence

have been rarely more than a few years apart. Of its various later

manifestations of energy we select for description that of 1767, of

which an interesting account by a careful observer is extant.

GREAT ERUPTION OF 1767

From the 10th of December, 1766, to March, 1767, Vesuvius was quiet;

then it began to throw up stones from time to time. In April the throws

were more frequent, and at night the red glare grew stronger on the

cloudy columns which hung over the crater. These repeated throws of

cinders, ashes and pumice-stones so much increased the small cone of

eruption which had been left in the centre of the flat crateral space

that its top became visible at a distance.

On the 7th of August there issued a small stream of lava from a breach

in the side of a small cone; the lava gradually filled the space between

the cone and the crateral edge; on the 12th of September it overflowed

the crater, and ran down the mountain. Stones were ejected which took

ten seconds in their fall, from which it may be computed that the height

which the stones reached was 1,600 feet. Padre Torre, a great observer

of Vesuvius, says they went up above a thousand feet. The lava ceased

on the 18th of October, but at 8 A. M. on the 19th it rushed out at a

different place, after volleys of stones had been thrown to an immense

height, and the huge traditional pine-tree of smoke reappeared. On this

occasion that vast phantom extended its menacing shadow over Capri, at a

distance of twenty-eight miles from Vesuvius.

The lava at first came out of a mouth about one hundred yards below the

crater, on the side toward Monte Somma. While occupied in viewing this

current, the observer heard a violent noise within the mountain; saw it

split open at the distance of a quarter of a mile, and saw from the new

mouth a mountain of liquid fire shoot up many feet, and then, like a

torrent, roll on toward him. The earth shook; stones fell thick around

him; dense clouds of ashes darkened the air; loud thunders came from the

mountain top, and he took to precipitate flight. The Padre’s account is

too lively and instructive for his own words to be omitted.

PADRE TORRE’S NARRATIVE

“I was making my observations upon the lava, which had already, from the

spot where it first broke out, reached the valley, when, on a sudden,

about noon, I heard a violent noise within the mountain, and at a spot

about a quarter of a mile off the place where I stood the mountain

split; and with much noise, from this new mouth, a fountain of liquid

fire shot up many feet high, and then like a torrent rolled on directly

towards us. The earth shook at the same time that a volley of stones

fell thick upon us; in an instant clouds of black smoke and ashes caused

almost a total darkness; the explosions from the top of the mountain

were much louder than any thunder I ever heard, and the smell of the

sulphur was very offensive. My guide, alarmed, took to his heels; and

I must confess that I was not at my ease. I followed close, and we ran

near three miles without stopping; as the earth continued to shake under

our feet, I was apprehensive of the opening of a fresh mouth which might

have cut off our retreat.

“I also feared that the violent explosions would detach some of the

rocks off the mountain of Somma, under which we were obliged to pass;

besides, the pumice-stones, falling upon us like hail, were of such a

size as to cause a disagreeable sensation in the part upon which they

fell. After having taken breath, as the earth trembled greatly I thought

it most prudent to leave the mountain and return to my villa, where I

found my family in great alarm at the continual and violent explosions

of the volcano, which shook our house to its very foundation, the doors

and windows swinging upon their hinges.

“About two of the clock in the afternoon (19th) another lava stream

forced its way out of the same place from whence came the lava of last

year, so that the conflagration was soon as great on this side of the

mountain as on the other which I had just left. I observed on my way to

Naples, which was in less than two hours after I had left the mountain,

that the lava had actually covered three miles of the very road through

which we had retreated. This river of lava in the Atrio del Cavallo was

sixty or seventy feet deep, and in some places nearly two miles broad.

Besides the explosions, which were frequent, there was a continued

subterranean and violent rumbling noise, which lasted five hours in

the night,--supposed to arise from contact of the lava with rain-water

lodged in cavities within. The whole neighborhood was shaken violently;

Portici and Naples were in the extremity of alarm; the churches were

filled; the streets were thronged with processions of saints, and

various ceremonies were performed to quell the fury of the mountain.

“In the night of the 20th, the occasion being critical, the prisoners in

the public jail attempted to escape, and the mob set fire to the gates

of the residence of the Cardinal Archbishop because he refused to bring

out the relics of St. Januarius. The 21st was a quieter day, but the

whole violence of the eruption returned on the 22d, at 10 A. M., with

the same thundering noise, but more violent and alarming. Ashes fell in

abundance in the streets of Naples, covering the housetops and balconies

an inch deep. Ships at sea, twenty leagues from Naples, were covered

with them.

“In the midst of these horrors, the mob, growing tumultuous and

impatient, obliged the Cardinal to bring out the head of St. Januarius,

at the extremity of Naples, toward Vesuvius; and it is well attested

here that the eruption ceased the moment the saint came in sight of

the mountain. It is true the noise ceased about that time after having

lasted five hours, as it had done the preceding days.

“On the 23d the lava still ran, but on the 24th it ceased; but smoke

continued. On the 25th there rose a vast column of black smoke, giving

out much forked lightning with thunder, in a sky quite clear except for

the smoke of the volcano. On the 26th smoke continued, but on the 27th

the eruption came to an end.”

This eruption was also described by Sir William Hamilton, who continued

to keep a close watch on the movements of the volcano for many years.

The next outbreak of especial violence took place in 1779, when what

seemed to the eye a column of fire ascended two miles high, while cinder

fragments fell far and wide, destroying the hopes of harvest throughout

a wide district. They fell in abundance thirty miles distant, and the

dust of the explosion was carried a hundred miles away.

In 1793 the crater became active again, and in 1794 after a period of

short tranquillity or comparative inaction, the mountain again became

agitated, and one of the most formidable eruptions known in the history

of Vesuvius began. It was in some respects unlike many others, being

somewhat peculiar as to the place of its outburst, the temperature of

the lava, and the course of the current. Breislak, an Italian geologist,

observed the characteristic phenomena with the eye of science, and his

account supplies many interesting facts.

BREISLAK ON THE ERUPTION OF 1794

Breislak remarked certain changes in the character of the earth’s

motions during this six hours’ eruption, which led him to some

particular conjecture of the cause. At the beginning the trembling was

continual, and accompanied by a hollow noise, similar to that occasioned

by a river falling into a subterranean cavern. The lava, at the time

of its being disgorged, from the impetuous and uninterrupted manner in

which it was ejected, causing it to strike violently against the walls

of the vent, occasioned a continual oscillation of the mountain. Toward

the middle of the night this vibratory motion ceased, and was succeeded

by distant shocks. The fluid mass, diminished in quantity, now pressed

less violently against the walls of the aperture, and no longer issued

in a continual and gushing stream, but only at intervals, when the

interior fermentation elevated the boiling matter above the mouth. About

4 A. M. the shocks began to be less numerous, and the intervals between

them rendered their force and duration more perceptible.

During this tremendous eruption at the base of the Vesuvian cone, and

the fearful earthquakes which accompanied it, the summit was tranquil.

The sky was serene, the stars were brilliant, and only over Vesuvius

hung a thick, dark smoke-cloud, lighted up into an auroral arch by the

glare of a stream of fire more than two miles long, and more than a

quarter of a mile broad. The sea was calm, and reflected the red glare;

while from the source of the lava came continual jets of uprushing

incandescent stones. Nearer to view, Torre del Greco in flames, and

clouds of black smoke, with falling houses, presented a dark and

tragical foreground, heightened by the subterranean thunder of the

mountain, and the groans and lamentations of fifteen thousand ruined

men, women and children.

The heavy clouds of ashes which were thrown out on this occasion

gathered in the early morning into a mighty shadow over Naples and the

neighborhood; the sun rose pale and obscure, and a long, dim twilight

reigned afterward.

Such were the phenomena on the western side of Vesuvius. They were

matched by others on the eastern aspect, not visible at Naples, except

by reflection of their light in the atmosphere. The lava on this side

flowed eastward, along a route often traversed by lava, by the broken

crest of the Cognolo and the valley of Sorienta. The extreme length to

which this current reached was not less than an Italian mile. The cubic

content was estimated to be half that already assigned to the western

currents. Taken together they amounted to 20,744,445 cubic metres, or

2,804,440 cubic fathoms; the constitution of the lava being the same in

each, both springing from one deep-seated reservoir of fluid rock.

The eruption of lava ceased on the 16th, and then followed heavy

discharges of ashes, violent shocks of earthquakes, thunder and

lightning in the columns of vapors and ashes, and finally heavy rains,

lasting till the 3d of July. The barometer during all the eruption was

steady.

Breislak made an approximate calculation of the quantity of ashes which

fell on Vesuvius during this great eruption, and states the result as

equal to what would cover a circular area 6 kilometres (about 3 1/2

English miles) in radius, and 39 centimetres (about 15 inches) in depth.

STRANGE EFFECTS

Among the notable things which attended this eruption, it is recorded

that in Torre del Greco metallic and other substances exposed to

the current were variously affected. Silver was melted, glass became

porcelain, iron swelled to four times its volume and lost its texture.

Brass was decomposed, and its constituent copper crystallized in

cubic and octahedral forms aggregated in beautiful branches. Zinc was

sometimes turned to blende. During the eruption, the lip of the crater

toward Bosco Tre Case on the south east, fell in, or was thrown off, and

the height of that part was reduced 426 feet.

On the 17th, the sea was found in a boiling state 100 yards off the new

promontory made by the lava of Torre del Greco, and no boat could remain

near it on account of the melting of the pitch in her bottom. For nearly

a month after the eruption vast quantities of fine white ashes, mixed

with volumes of steam, were thrown out from the crater; the clouds

thus generated were condensed into heavy rain, and large tracts of the

Vesuvian slopes were deluged with volcanic mud. It filled ravines, such

as Fosso Grande, and concreted and hardened there into pumiceous tufa--a

very instructive phenomenon.

Immense injury was done to the rich territory of Somma, Ottajano and

Bosco by heavy rains, which swept along cinders, broke up the road and

bridges, and overturned trees and houses for the space of fifteen days.

There were few years during the nineteenth century in which Vesuvius did

not show symptoms of its internal fires, and at intervals it manifested

much activity, though not equaling the terrible eruptions of its past

history. The severest eruptions in that century were those of 1871 and

1876. In the first a sudden emission of lava killed twenty spectators at

the mouth of the crater, and only spent its fury after San Sebastian and

Massa had been well nigh annihilated. Fragments of rock were thrown up

to the height of 4,000 feet, and the explosions were so violent that

the whole countryside fled panic stricken to Naples. The activity of

the volcano, accompanied by distinct shocks of earthquake, lasted for a

week.

In 1876, for three weeks together, lava streamed down the side of

Vesuvius, sweeping away the village of Cercolo and running nearly to the

sea at Ponte Maddaloni. There were then formed ten small craters within

the greater one. But these were united by a later eruption in 1888, and

pressure from beneath formed a vast cone where they had been.

HARDIHOOD OF THE PEOPLE

It may seem strange that so dangerous a neighborhood should be

inhabited. But so it is. Though Pompeii, Herculaneum and Stabiae lie

buried beneath the mud and ashes belched out of the mouth of Vesuvius,

the villages of Portici and Revina, Torre del Greco and Torre del

Annunziata have taken their place, and a large population, cheerful

and prosperous, flourishes around the disturbed mountain and over the

district of which it is the somewhat untrustworthy safety-valve.

It is thus that man, in his eagerness to cultivate all available parts

of the earth, dares the most frightful perils and ventures into the most

threatening situations, seeking to snatch the means of life from

the very jaws of death. The danger is soon forgotten, the need of

cultivation of the ground is ever pressing, and no threats of peril seem

capable of restraining the activity of man for many years. Though the

proposition of abandoning the Island of Martinique has been seriously

considered, the chances are that, before many years have passed, a

cheerful and busy population will be at work again on the flanks of Mont

Pelee.

MOUNT ETNA

On the eastern coast of the Island of Sicily, and not far from the

sea, rises in solitary grandeur Mount Etna, the largest and highest of

European volcanoes. Its height above the level of the sea is a little

over 10,870 feet, considerably above the limit of perpetual snow.

It accordingly presents the striking phenomenon of volcanic vapors

ascending from a snow-clad summit. The base of the mountain is

eighty-seven miles in circumference, and nearly circular; but there is

a wide additional extent all around overspread by its lava. The lower

portions of the mountain are exceedingly fertile, and richly adorned

with corn-fields, vineyards, olive-groves and orchards. Above this

region are extensive forests, chiefly of oak, chestnut, and pine, with

here and there clumps of cork-trees and beech. In this forest region are

grassy glades, which afford rich pasture to numerous flocks. Above the

forest lies a volcanic desert, covered with black lava and slag. Out of

this region, which is comparatively flat rises the principal cone, about

1,100 feet in height, having on its summit the crater, whence sulphurous

vapors are continually evolved.

The great height of Etna has exerted a remarkable influence on its

general conformation: for the volcanic forces have rarely been of

sufficient energy to throw the lava quite up to the crater at the

summit. The consequence has been, that numerous subsidiary craters and

cones have been formed all around the flanks of the mountain, so that it

has become rather a cluster of volcanoes than a single volcanic cone.

The eruptions of this mountain have been numerous, records of them

extending back to several centuries before the Christian era, while

unrecorded ones doubtless took place much further back. After the

beginning of the Christian era, and more especially after the breaking

forth of Vesuvius in 79 A. D., Etna enjoyed longer intervals of repose.

Its eruptions since that time have nevertheless been numerous--more

especially during the intervals when Vesuvius was inactive--there being

a sort of alternation between the periods of great activity of the two

mountains; although there are not a few instances of their having been

both in action at the same time.

SIMILARITY IN ETNA’S ERUPTIONS

There is a great similarity in the character of the eruptions of Etna.

Earthquakes presage the outburst, loud explosions follow, rifts and

bocche del fuoco open in the sides of the mountain; smoke, sand, ashes

and scoriae are discharged, the action localizes itself in one or more

craters, cinders are thrown up and accumulate around the crater and

cone, ultimately lava rises and frequently breaks down one side of the

cone where the resistance is least; then the eruption is at an end.

Smyth says: “The symptoms which precede an eruption are generally

irregular clouds of smoke, ferilli or volcanic lightnings, hollow

intonations and local earthquakes that often alarm the surrounding

country as far as Messina, and have given the whole province the name

of Val Demone, as being the abode of infernal spirits. These agitations

increase until the vast cauldron becomes surcharged with the fused

minerals, when, if the convulsion is not sufficiently powerful to force

them from the great crater (which, from its great altitude and the

weight of the candent matter, requires an uncommon effort), they explode

through that part of the side which offers the least resistance with a

grand and terrific effect, throwing red-hot stones and flakes of fire to

an incredible height, and spreading ignited cinders and ashes in every

direction.”

After the eruption of ashes, lava frequently follows, sometimes rising

to the top of the cone of cinders, at others disrupting it on the least

resisting side. When the lava has reached the base of the cone it begins

to flow down the mountain, and, being then in a very fluid state, it

moves with great velocity. As it cools, the sides and surface begin to

harden, its velocity decreases, and after several days it moves only

a few yards an hour. The internal portions, however, part slowly with

their heat, and months after the eruption clouds of steam arise from the

black and externally cold lava-beds after rain; which, having penetrated

through the cracks, has found its way to the heated mass within.

THE ERUPTION OF 1669

The most memorable of the eruptions of Etna was that which elevated the

double cone of Monte Rossi and destroyed a large part of the city

of Catania. It happened in the year 1669, and was preceded by an

earthquake, which overthrew the town of Nicolosi, situated ten miles

inland from Catania, and about twenty miles from the top of Etna. The

eruption began with the sudden opening of an enormous fissure, extending

from a little way above Nicolosi to within about a mile of the top of

the principal cone, its length being twelve miles, its average breadth

six feet, its depth unknown.

We have a more detailed account of this eruption than of any preceding

one, as it was observed by men of science from various countries. The

account from which we select is that of Alfonso Borelli, Professor of

Mathematics in Catania.

From the fissure above mentioned, he says, there came a bright light.

Six mouths opened in a line with it and emitted vast columns of smoke,

accompanied by loud bellowings which could be heard forty miles off.

Towards the close of the day a crater opened about a mile below the

others, which ejected red-hot stones to a considerable distance, and

afterward sand and ashes which covered the country for a distance of

sixty miles. The new crater soon vomited forth a torrent of lava which

presented a front of two miles; it encircled Monpilieri, and afterward

flowed towards Belpasso, a town of 8,000 inhabitants, which was speedily

destroyed. Seven mouths of fire opened around the new crater, and

in three days united with it, forming one large crater 800 feet in

diameter. All this time the torrent of lava continued to descend, it

destroying the town of Mascalucia on the 23d of March. On the same day

the crater cast up great quantities of sand, ashes and scoriae, and

formed above itself the great double-coned hill now called Monte Rossi,

from the red color of the ashes of which it is mainly composed.

VILLAGES AND CITIES BURIED

On the 25th very violent earthquakes occurred, and the cone above the

great central crater was shaken down into the crater for the fifth time

since the first century A. D. The original current of lava divided

into three streams, one of which destroyed San Pietro, the second

Camporotondo, and the third the lands about Mascalucia and afterward the

village of Misterbianco. Fourteen villages were altogether destroyed,

and the lava flowed toward Catania. At Albanelli, two miles from the

city, it undermined a hill covered with cornfields and carried it

forward a considerable distance. A vineyard was also seen to be floating

on its fiery surface. When the lava reached the walls of Catania, it

accumulated without progression until it rose to the top of the wall, 60

feet in height, and it then fell over in a fiery cascade and overwhelmed

a part of the city. Another portion of the same stream threw down 120

feet of the wall and flowed into the city.

On the 23d of April the lava reached the sea, which it entered as a

stream 600 yards broad and 40 feet deep. The stream had moved at the

rate of thirteen miles in twenty days, but as it cooled it moved

less quickly, and during the last twenty-three days of its course, it

advanced only two miles. On reaching the sea the water, of course,

began to boil violently, and clouds of steam arose, carrying with them

particles of scoriae. Towards the end of April the stream on the west

side of Catania, which had appeared to be consolidated, again burst

forth, and flowed into the garden of the Benedictine Monastery of San

Niccola, and then branched off into the city. Attempts were made to

build walls to arrest its progress.

An attempt of another kind was made by a gentleman of Catania, named

Pappalardo, who took fifty men with him, having previously provided them

with skins for protection from the intense heat and with crowbars to

effect an opening in the lava. They pierced the solid outer crust of

solidified lava, and a rivulet of the molten interior immediately gushed

out and flowed in the direction of Paterno, whereupon 500 men of that

town, alarmed for its safety, took up arms and caused Pappalardo and his

men to desist. The lava did not altogether stop for four months, and two

years after it had ceased to flow it was found to be red hot beneath the

surface. Even eight years after the eruption quantities of steam escaped

from the lava after a shower of rain.

THE STONES EJECTED

The stones which were ejected from the crater during this eruption

were often of considerable magnitude, and Borelli calculated that the

diameter of one which he saw was 50 feet; it was thrown to a distance

of a mile, and as it fell it penetrated the earth to a depth of 23 feet.

The volume of lava emitted during the eruption amounted to many millions

of cubic feet. Ferara considers that the length of the stream was at

least fifteen miles, while its average width was between two and three

miles, so that it covered at least forty square miles of surface.

Among the towns overflowed by this great eruption was Mompilieri.

Thirty-five years afterward, in 1704, an excavation was made on the site

of the principal church of this place, and at the depth of thirty-five

feet the workmen came upon the gate, which was adorned with three

statues. From under an arch which had been formed by the lava, one

of these statues, with a bell and some coins, were extracted in good

preservation. This fact is remarkable; for in a subsequent eruption,

which happened in 1766, a hill about fifty feet in height, being

surrounded on either side by two streams of lava, was in a quarter of

an hour swept along by the current. The latter event may be explained by

supposing that the hill in question was cavernous in its structure,

and that the lava, penetrating into the cavities, forced asunder their

walls, and so detached the superincumbent mass from its supports.

It is not by its streams of fire alone that Etna ravages the valleys and

plains at its base. It sometimes also deluges them with great floods of

water. On the 2d of March, 1755, two streams of lava, issuing from the

highest crater, were at once precipitated on an enormous mass of very

deep snow, which then clothed the summit. These fiery currents ran

through the snow to a distance of three miles, melting it as they

flowed. The consequence was, that a tremendous torrent of water rushed

down the sides of the mountain, carrying with it vast quantities of

sand, volcanic cinders and blocks of lava, with which it overspread the

flanks of the mountain and the plains beneath, which it devastated in

its course.

The volume of water was estimated at 16,000,000 cubic feet, it forming

a channel two miles broad and in some places thirty-four feet deep,

and flowing at the rate of two-thirds of a mile in a minute. All the

winter’s snow on the mountain could not have yielded such a flood,

and Lyell considered that it melted older layers of ice which had been

preserved under a covering of volcanic dust.

ETNA IN 1819

Another great eruption took place in 1819, which presented some

peculiarities. Near the point whence the highest stream of lava

issued in 1811, there were opened three large mouths, which, with loud

explosions, threw up hot cinders and sand, illuminated by a strong glare

from beneath. Shortly afterwards there was opened, a little lower down,

another mouth, from which a similar eruption took place; and still

farther down there soon appeared a fifth, whence there flowed a torrent

of lava which rapidly spread itself over the Val del Bove. During the

first forty-eight hours it flowed nearly four miles, when it received a

great accession. The three original mouths became united into one large

crater, from which, as well as from the other two mouths below, there

poured forth a vastly augmented torrent of lava, which rushed with great

impetuosity down the same valley.

During its progress over this gentle slope, it acquired the usual crust

of hardened slag. It directed its course towards that point at which Val

del Bove opens into the narrow ravine beneath it--there being between

the two a deep and almost perpendicular precipice. Arrived at this

point, the lava-torrent leaped over the precipice in a vast cascade, and

with a thundering noise, arising chiefly from the crashing and breaking

up of the solid crust, which was in a great measure pounded to atoms by

the fall; it throwing up such vast clouds of dust as to awaken an alarm

that a fresh eruption had begun at this place, which is within the

wooded region.

A very violent eruption, which lasted more than nine months, commenced

on the 21st of August, 1852. It was first witnessed by a party of

English tourists, who were ascending the mountain from Nicolosi in order

to see the sunrise from the summit. As they approached the Casa Inglesi

the crater commenced to give forth ashes and flames of fire. In a narrow

defile they were met by a violent hurricane, which overthrew both the

mules and their riders, and urged them toward the precipices of the Val

del Bove. They sheltered themselves beneath some masses of lava, when

suddenly an earthquake shook the mountain, and their mules in terror

fled away. As day approached they returned on foot to Nicolosi,

fortunately without having sustained injury. In the course of the night

many bocche del fuoco (small lava vents) opened in that part of the Val

del Bove called the Bazo di Trifoglietto, a great fissure opened at the

base of the Giannicola Grande, and a crater was thrown up from which for

seventeen days showers of sand and scoriae were ejected.

EFFECT OF THE ERUPTION

During the next day a quantity of lava flowed down the Val del

Bove, branching off so that one stream advanced to the foot of Monte

Finocchio, and the other to Monte Calanna. Afterwards it flowed towards

Zaffarana, and devastated a large tract of wooded region. Four days

later a second crater was formed near the first, from which lava was

emitted, together with sand and scoriae, which caused cones to arise

around the craters. The lava moved but slowly, and towards the end of

August it came to a stand, only a quarter of a mile from Zaffarana.

On the second of September, Gemellaro ascended Monte Finocchio in the

Val del Bove in order to witness the outburst. He states that the hill

was violently agitated, like a ship at sea. The surface of the Val

del Bove appeared like a molten lake; scoriae were thrown up from the

craters to a great height, and loud explosions were heard at frequent

intervals. The eruption continued to increase in violence. On October

6 two new mouths opened in the Val del Bove, emitting lava which flowed

towards the valley of Calanna, and fell over the Salto della Giumenta,

a precipice nearly 200 feet deep. The noise which it produced was like

that of a clash of metallic masses. The eruption continued with abated

violence during the early months of 1853, and it did not finally cease

till May 27. The entire mass of lava ejected is estimated to have been

equal to an area six miles long by two miles broad, with an average

depth of about twelve feet.

This eruption was one of the grandest of all the known eruptions of

Etna. During its outflow more than 2,000,000,000 cubic feet of molten

lava was spread out over a space of three square miles. There have been

several eruptions since its date, but none of marked prominence, though

the mountain is rarely quiescent for any lengthened period.

THE LIPARI VOLCANOES

South-eastward of Ischia, between Calabria and Sicily, the Lipari

Islands arrest attention for the volcanic phenomena they present. On

one of these is Mount Vulcano, or Volcano, from which all this class of

mountains is named. At present the best known of the Lipari volcanoes

is Stromboli, which consists of a single mountain, having a very obtuse

conical form. It has on one side of it several small craters, of which

only one is at present in a state of activity.

The total height of the mountain is about 2000 feet, and the principal

crater is situated at about two-thirds of the height. Stromboli is one

of the most active volcanoes in the world. It is mentioned as being in

a state of activity by several writers before the Christian era, and the

commencement of its operations extends into the past beyond the limits

of tradition. Since history began its action has never wholly ceased,

although it may have varied in intensity from time to time.

It has been observed that the violence of its eruptive force has a

certain dependence on the weather--being always most intense when the

barometer is lowest. From the position of the crater, it is possible to

ascend the mountain and look down upon it from above. Even when viewed

in this manner, it presents a very striking appearance. While there is

an uninterrupted continuance of small explosions, there is a frequent

succession of more violent eruptions, at intervals varying in length

from seven to fifteen minutes.

HOFFMAN AT STROMBOLI

Several eminent observers have approached quite close to the crater,

and examined it narrowly. One of these was M. Hoffman, who visited it in

1828.

This eminent geologist, while having his legs held by his companions,

stretched his head over the precipice, and, looking right down into the

mouth of one of the vents of the crater immediately under him, watched

the play of liquid lava within it. Its surface resembled molten silver,

and was constantly rising and falling at regular intervals. A bubble of

white vapor rose and escaped, with a decrepitating noise, at each ascent

of the lava--tossing up red-hot fragments of scoria, which continued

dancing up and down with a sort of rhythmic play upon the surface.

At intervals of fifteen minutes or so, there was a pause in these

movements. Then followed a loud report, while the ground trembled, and

there rose to the surface of the lava an immense bubble of vapor. This,

bursting with a crackling noise, threw out to the height of about 1200

feet large quantities of red-hot stones and scoriae, which, describing

parabolic curves, fell in a fiery, shower all around. After another

brief repose, the more moderate action was resumed as before.

Lipari, a neighboring volcano, was formerly more active than Stromboli,

though for centuries past it has been in a state of complete quiescence.

The Island of Volcano lies south of Lipari. Its crater was active before

the Christian era, and still emits sulphurous and other vapors. At

present its main office is to serve as a sulphur mine. Thus the peak

which gives title to all fire-breathing mountains has become a servant

to man. So are the mighty fallen!

CHAPTER XXIII.

Skaptar Jokull and Hecla, the Great Icelandic Volcanoes.

The far-northern island of Iceland, on the verge of the frozen Arctic

realm, is one of the most volcanic countries in the world, whether we

regard the number of volcanoes concentrated in so small a space, or the

extraordinary violence of their eruptions. Of volcanic mountains there

are no less than twenty which have been active during historical times.

Skaptar in the north, and Hecla in the south, being much the best known.

In all, twenty-three eruptions are on record.

Iceland’s volcanoes rival Mount Aetna in height and magnitude, their

action has been more continuous and intense, and the range of volcanic

products is far greater than in Sicily. The latter island, indeed, is

not one-tenth of volcanic origin, while the whole of Iceland is due

to the work of subterranean forces. It is entirely made up of volcanic

rocks, and has seemingly been built up during the ages from the depths

of the seas. It is reported, indeed, that a new island, the work

of volcanic forces, appeared opposite Mount Hecla in 1563; but this

statement is open to doubt.

VOLCANOES IN ICELAND

The eruptions of the volcanoes in Iceland have been amongst the most

terrible of those carefully recorded. The cold climate of the island

and the height of the mountains produce vast quantities of snow and ice,

which cover the volcanoes and fill up the cracks and valleys in their

sides. When, therefore, an eruption commences, the intense heat of the

boiling lava, and of the steam which rushes forth from the crater, makes

the whole mountain hot, and vast masses of ice, great fields of snow,

and deluges of water roll down the hill-sides into the plains. The lava

pours from the top and from cracks in the side of the mountain, or is

ejected hundreds of feet, to fall amongst the ice and snow; and the

great masses of red-hot stone cast forth, accompanied by cinders and

fine ashes, splash into the roaring torrent, which tears up rocks in its

course and devastates the surrounding country for miles.