The San Francisco Calamity

Part 4 out of 7

covered; the Campania presented the appearance of a Dakota prairie
after a blizzard of snow, though everything was gray instead of
white. The ashes lay in drifts knee deep. As the volcano was
approached semi-night replaced the day, the gloom being so deep
that telegraph poles twenty feet away could not be seen. Breathing
was difficult, and the smoke made the eyes water. At Naples,
however, a favorable wind had cleared the air of smoke, the sun
shone brightly, and the versatile people were happy once more. The
goggles and eye-screens had disappeared, but the streets were
anything but comfortable, for some six thousand men were at work
clearing the ashes from the roofs and main streets and piling them
in the middle of the narrow streets, making the passage of vehicles
very difficult and the sidewalks far from comfortable for foot
passengers.

But while brightness and joy reigned at Naples, there were gruesome
scenes within the volcanic zone. At Bosco Trecase soldiers carried
on the work of exhumation, being able to work only an hour at a
time on account of the advanced stage of decomposition of the
bodies. Many of these were shapeless, unrecognizable masses of
flesh and bones, while others were little disfigured. To lessen
the danger of an epidemic the bodies were buried as quickly as
possible in quicklime.

On Sunday, the 15th, the searchers at Ottejano were surprised at
finding two aged women still alive, after six days' entombment in
the ruins. They were among those who had been buried by the
falling walls a week before. The rafters of the house had
protected them, and a few morsels of food in their pockets aided to
keep them alive. At some points there the ashes were ten feet
deep. At San Giuseppe bodies of women were found in whose hands
were coins and jewels, and one woman held a jewelled rosary. This
recalls the results of exploration at Herculaneum and Pompeii,
where were similar instances of death overtaking the victims of the
volcano while fleeing with their jewels in their hands.

It is interesting to learn that two men stood heroically to their
post of duty during the whole scene of the explosion, Professor
Matteucci, Director of the Royal Observatory, and his American
assistant, Professor Frank A. Perret, of New York. Though the
building occupied by them was exposed to the full force of the rain
of stones from the burning mountain, they remained undauntedly at
their post through that week of terror. On the 14th some of that
venturesome fraternity, the newspaper correspondents, reached their
eyrie on the highest habitable point on Vesuvius and heard the
story of their experiences.

THE HEROES OF THE OBSERVATORY.

For several days Professors Matteucci and Perret and their two
servants had been cut off from the outside world and bombarded by
the volcano, their rations consisting of bread, cheese and dried
onions, until on Friday a hardy guide was induced to push through
to them with some provisions. During the eruption the Professor
had kept at his instruments, taking observations day and night and
making calculations in the midst of the inferno. Roughly dressed,
he looked like a Western cowboy after a hard ride in a dust storm.
The portico where he stood was knee deep in ashes, and from the
observatory terrace narrow paths had been cut through the ashes,
but as far as the eye could reach an ocean of ashes and twisted
rivers were alone visible, with Vesuvius rising grimly in the
midst. The great monster was enveloped in a cloak of white, as if
buried under a snowstorm, its surface being here and there slit
with gulches in which lava ran. At the bottom of one of those
gulches lay the wrecked remnants of the peninsular railway, a
portion of its twisted cable protruding through the ashes. As the
correspondents ascended the mountain they were surprised by the
apparition of natives, men wrinkled with age, who emerged from
dugouts just below the observatory and offered them milk and eggs,
just as if they were ordinary visitors to the volcano. As they
descended they heard the sound of a mandolin from one of these
dugouts. Evidently Vesuvius had no terrors for these case-hardened
veterans.

We have already told the story gleaned by the correspondents from
the daring scientists. Matteucci completed his record of boldness
on Friday, the 13th, by climbing to a point far above the
observatory, at the imminent risk of his life, to observe the
conditions then existing. From what he says he believed the end of
the disturbance near, though he did not venture to predict. As for
the ashes, which a light wind was then blowing in a direction away
from Naples, he said: "The ill wind is now blowing good to other
places, for ashes are the best fertilizer it is possible to use.
It is merely a question just now of having too much of a good
thing."

This is a fact so far as the volcanic ash is concerned. An
examination of the ashes a few days ago shows that they will prove
an active and valuable fertilizer. The fertile slopes of Vesuvius
have ever been an allurement to the vine-grower, four crops a year
being a temptation no possible danger could drive him from, and as
soon as the mountain grows surely peaceful after this eruption, we
shall find its farmers risking again the chance of its uncertain
temper. But this is not the case with the land covered with lava
and cinders. Time for their disintegration is necessary before
they can be brought under cultivation, and this is a matter of
years. After the great eruption of 1871-72 the land covered with
cinders did not bear crops for seven years, and there is no reason
that they will do so sooner on the present occasion. So for years
to come much of the volcanic soil must remain a barren and desert
void.

CHAPTER XVI.

The Great Lisbon and Calabrian Earthquakes.

To our account of the great earth convulsions of San Francisco it
is in place to append a description of some similar events of older
date. It is due to the same causes, whatever these causes may be,
the imprisoned forces within the earth acting over great distances
during the earthquake, while they are concentrated within some
limited space when the volcano begins its work. The earthquake is
the most terrible to mankind of all the natural agencies of
destruction. While the volcano usually has a greater permanent
effect upon surface conditions, it is, as a rule, much less
destructive to human life, the earthquake often shaking down cities
and burying all their inhabitants in one common grave. Violent
earthquakes are also of far more frequent occurrence than
destructive volcanic eruptions, many hundreds of them having taken
place during the historic period.

While the earthquake is only indirectly connected with the subject
of our work, it seems desirable to make some mention of it here, at
least so far as relates to those terrible convulsions whose
destructiveness has given them special prominence in the history of
great disasters. Ancient notable examples are those which threw
down the famous Colossus of Rhodes and the Pharos of Alexandria.
The city of Antioch was a terrible sufferer from this affliction,
it having been devastated some time before the Christian era, while
in the year 859 more than 15,000 of its houses were destroyed. Of
countries subject to earthquakes, Japan has been an especial
sufferer, in some cases mountains or islands being elevated in
association with shocks; in others, great tracts of land being
swallowed up by the sea. The number of deaths in some of these
instances was enormous.

Numerous thrilling examples of the destructive work of the
earthquake at various periods are on record. Of these we have
given elsewhere a tabular list of the more important, and shall
confine ourselves to a few striking examples of its destructive
action. In the record of great earthquakes, one of the most famous
is that which in 1755 visited the city of Lisbon, the capital of
Portugal, and left that populous, place in ruin and dire distress.
It may be well to recall the details of this dire event to the
memories of our readers.

THE GREAT LISBON EARTHQUAKE

On the night of the 31st of October, 1755, the citizens of the fair
city of Lisbon lay down to sleep, in merciful ignorance of what was
awaiting them on the morrow. The morning of the 1st of November
dawned, and gave no sign of approaching calamity. The sun rose in
its brightness, the warmth was genial, the breezes gentle, the sky
serene. It was All Saints' Day--a high festival of the Church of
Rome. The sacred edifices were thronged with eager crowds, and the
ceremonies were in full progress, when the assembled throngs were
suddenly startled from their devotions. From the ground beneath
came fearful sounds that drowned the peal of the organ and the
voices of the choirs. These underground thunders having rolled
away, an awful silence ensued. The panic-stricken multitudes were
paralyzed with terror. Immediately after the ground began to heave
with a long and gentle swell, producing giddiness and faintness
among the people. The tall piles swayed to and fro, like willows
in the wind. Shrieks of horror rose from the terrified assembly.
Again the earth heaved, and this time with a longer and higher
wave. Down came the ponderous arches, the stately columns, the
massive walls, the lofty spires, tumbling upon the heads of priests
and people. The graven images, the deified wafers, and they who
had knelt in adoration before them--the worshipped and the
worshippers alike--were in a moment buried under one
undistinguishable mass of horrible ruins. Only a few, who were
near the doors, escaped to tell the tale.

It fared no better with those who had remained in their dwellings.
The terrible earth-wave overthrew the larger number of the private
houses in the city, burying their inhabitants under the crumbling
walls. Those who were in the streets more generally escaped,
though some there, too, were killed by falling walls.

The sudden overthrow of so many buildings raised vast volumes of
fine dust, which filled the atmosphere and obscured the sun,
producing a dense gloom. The air was full of doleful sounds--the
groans of agony from the wounded and the dying, screams of despair
from the horrified survivors, wails of lamentation from the
suddenly bereaved, dismal howlings of dogs, and terrified cries of
other animals.

In two or three minutes the clouds of dust fell to the ground, and
disclosed the scene of desolation which a few seconds had wrought.
The ruin, though general, was not universal. A considerable number
of houses were left standing--fortunately tenantless--for a third
great earth-wave traversed the city, and most of the buildings
which had withstood the previous shocks, already severely shaken,
were entirely overthrown.

WATER ADDS TO THE DESTRUCTION

The last disaster filled the surviving citizens with the impulse of
flight. The more fortunate of them ran in the direction of the
open country, and succeeded in saving their lives; but a great
multitude rushed down to the harbor, thinking to escape by sea.
Here, however, they were met by a new and unexpected peril. The
tide, after first retreating for a little, came rolling in with an
immense wave, about fifty feet in height, carrying with it ships,
barges and boats, and dashing them in dire confusion upon the
crowded shore. Overwhelmed by this huge wave, great numbers were,
on its retreat, swept into the seething waters and drowned. A vast
throng took refuge on a fine new marble quay, but recently
completed, which had cost much labor and expense. This the sea-
wave had spared, sweeping harmless by. But, alas! it was only for
a moment. The vast structure itself, with the whole of its living
burden, sank instantaneously into an awful chasm which opened
underneath. The mole and all who were on it, the boats and barges
moored to its sides, all of them filled with people, were in a
moment ingulfed. Not a single corpse, not a shred of raiment, not
a plank nor a splinter floated to the surface, and a hundred
fathoms of water covered the spot. To the first great sea-wave
several others succeeded, and the bay continued for a long time in
a state of tumultuous agitation.

About two hours after the first overthrow of the buildings, a new
element of destruction came into play. The fires in the ruined
houses kindled the timbers, and a mighty conflagration, urged by a
violent wind, soon raged among the ruins, consuming everything
combustible, and completing the wreck of the city. This fire,
which lasted four days, was not altogether a misfortune. It
consumed the thousands of corpses which would otherwise have
tainted the air, adding pestilence to the other misfortunes of the
survivors. Yet they were threatened with an enemy not less
appalling, for famine stared them in the face. Almost everything
eatable within the precincts of the city had been consumed. A set
of wretches, morever, who had escaped from the ruins of the
prisons, prowled among the rubbish of the houses in search of
plunder, so that whatever remained in the shape of provisions fell
into their hands and was speedily devoured. They also broke into
the houses that remained standing, and rifled them of their
contents. It is said that many of those who had been only injured
by the ruins, and might have escaped by being extricated, were
ruthlessly murdered by those merciless villains.

The total loss of life by this terrible catastrophe is estimated at
60,000 persons, of whom about 40,000 perished at once, and the
remainder died afterwards of the injuries and privations they
sustained. Twelve hundred were buried in the ruins of the general
hospital, eight hundred in those of the civil prison, and several
thousands in those of the convents. The loss of property amounted
to many millions sterling.

WIDE-SPREAD DESTRUCTION

Although the earth-wave traversed the whole city, the shock was
felt more severely in some quarters than in others. All the older
part of the town, called the Moorish quarter, was entirely
overthrown; and of the newer part, about seventy of the principal
streets were ruined. Some buildings that withstood the shocks were
destroyed by fire. The cathedral, eighteen parish churches, almost
all the convents, the halls of the inquisition, the royal
residence, and several other fine palaces of the nobility and
mansions of the wealthy, the custom-houses, the warehouses filled
with merchandise, the public granaries filled with corn, and large
timber yards, with their stores of lumber, were either overthrown
or burned.

The king and court were not in Lisbon at the time of this great
disaster, but were living in the neighborhood at the castle of
Belem, which escaped injury. The royal family, however, were so
alarmed by the shocks, that they passed the following night in
carriages out of doors. None of the officers of state were with
them at the time. On the following morning the king hastened to
the ruined city, to see what could be done toward restoring order,
aiding the wounded, and providing food for the hungry.

The royal family and the members of the court exerted themselves to
the uttermost, the ladies devoting themselves to the preparation of
lint and bandages, and to nursing the wounded, the sick, and the
dying, of whom the numbers were overwhelming. Among the sufferers
were men of quality and once opulent citizens, who had been reduced
in a moment to absolute penury. The kitchens of the royal palace,
which fortunately remained standing, were used for the purpose of
preparing food for the starving multitudes. It is said that during
the first two or three days a pound of bread was worth an ounce of
gold. One of the first measures of the government was to buy up
all the corn that could be obtained in the neighborhood of Lisbon,
and to sell it again at a moderate price, to those who could afford
to buy, distributing it gratis to those who had nothing to pay.

For about a month afterward earthquake shocks continued, some of
them severe. It was several months before any of the citizens
could summon courage to begin rebuilding the city. But by degrees
their confidence returned. The earth had relapsed into repose, and
they set about the task of rebuilding with so much energy, that in
ten years Lisbon again became one of the most beautiful capitals of
Europe.

CHARACTERISTICS OF THE LISBON EARTHQUAKE

The most distinguishing peculiarities of this earthquake were the
swallowing up of the mole, and the vast extent of the earth's
surface over which the shocks were felt. Several of the highest
mountains in Portugal were violently shaken, and rent at their
summits; huge masses falling from them into the neighboring
valleys. These great fractures gave rise to immense volumes of
dust, which at a distance were mistaken for smoke by those who
beheld them. Flames were also said to have been observed: but if
there were any such, they were probably electrical flashes produced
by the sudden rupture of the rocks.

The portion of the earth's surface convulsed by this earthquake is
estimated by Humboldt to have been four times greater than the
whole extent of Europe. The shocks were felt not only over the
Spanish peninsula, but in Morocco and Algeria they were nearly as
violent. At a place about twenty-four miles from the city of
Morocco, there is said to have occurred a catastrophe much
resembling what took place at the Lisbon mole. A great fissure
opened in the earth, and an entire village, with all its
inhabitants, upwards of 8,000 in number, were precipitated into the
gulf, which immediately closed over its prey.

EARTHQUAKES IN CALABRIA

Of the numerous other examples of destructive earthquakes which
might be chosen from Old World annals, it will not be amiss to
append a brief account of those which took place in Calabria,
Italy, in 1783. These, while less wide-spread in their influence,
were much longer in duration than the Lisbon cataclysm, since they
continued, at intervals, from the 5th of February until the end of
the year. The shocks were felt all over Sicily and as far north as
Naples, but the area of severe convulsion was comparatively
limited, not exceeding five hundred square miles.

The centre of disturbance seems to have been under the town of
Oppido in the farther Calabria, and it extended in every direction
from that spot to a distance of about twenty-two miles, with such
violence as to overthrow every city, town and village lying within
that circle. This ruin was accomplished by the first shock on the
5th of February. The second, of equal violence, on the 28th of
March, was less destructive, only because little or nothing had
been left for it to overthrow.

At Oppido the motion was in the nature of a vertical upheaval of
the ground, which was accompanied by the opening of numerous large
chasms, into some of which many houses were ingulfed, the chasms
closing over them again almost immediately. The town itself was
situated on the summit of a hill, flanked by five steep and
difficult slopes; it was so completely overthrown by the first
shock that scarcely a fragment of wall was left standing. The hill
itself was not thrown down, but a fort which commanded the approach
to the place was hurled into the gorge below. It was on the flats
immediately surrounding the site of the town and on the rising
grounds beyond them that the great fissures and chasms were opened.
On the slope of one of the hills opposite the town there appeared a
vast chasm, in which a large quantity of soil covered with vines
and olive-trees was engulfed. This chasm remained open after the
shock, and was somewhat in the form of an amphitheatre, 500 feet
long and 200 feet in depth.

MOST CALAMITOUS OF THE LANDSLIPS

The most calamitous of the landslips occurred on the sea-coast of
the Straits of Messina, near the celebrated rock of Scilla, where
huge masses fell from the tall cliffs, overwhelming many villas and
gardens. At Gian Greco a continuous line of precipitous rocks,
nearly a mile in length, tumbled down. The aged Prince of Scilla,
after the first great shock on the 5th of February, persuaded many
of his vassals to quit the dangerous shore, and take refuge in the
fishing boats--he himself showing the example. That same night,
however, while many of the people were asleep in the boats, and
others on a flat plain a little above the sea-level, another
powerful shock threw down from the neighboring Mount Jaci a great
mass, which fell with a dreadful crash, partly into the sea, and
partly upon the plain beneath. Immediately the sea rose to a
height of twenty feet above the level ground on which the people
were stationed, and rolling over it, swept away the whole
multitude. This immense wave then retired, but returned with still
greater violence, bringing with it the bodies of the men and
animals it had previously swept away, dashing to pieces the whole
of the boats, drowning all that were in them, and wafting the
fragments far inland. The prince with 1,430 of his people perished
by this disaster.

It was on the north-eastern shore of Sicily, however, that the
greatest amount of damage was done. The first severe shock, on the
5th of February, overthrew nearly the whole of the beautiful city
of Messina, with great loss of life. The shore for a considerable
distance along the coast was rent, and the ground along the port,
which was before quite level, became afterwards inclined towards
the sea, the depth of the water having, at the same time, increased
in several parts, through the displacement of portions of the
bottom. The quay also subsided about fourteen inches below the
level of the sea, and the houses near it were much rent. But it
was in the city itself that the most terrible desolation was
wrought--a complication of disasters having followed the shock,
more especially a fierce conflagration, whose intensity was
augmented by the large stores of oil kept in the place.

IMMENSE DESTRUCTION

According to official reports made soon after the events, the
destruction caused by the earthquakes of the 5th of February and
28th of March throughout the two Calabrias was immense. About 320
towns and villages were entirely reduced to ruins, and about fifty
others seriously damaged. The loss of life was appalling--40,000
having perished by the earthquakes, and 20,000 more having
subsequently died from privation and exposure, or from epidemic
diseases bred by the stagnant pools and the decaying carcases of
men and animals. The greater number were buried amid the ruins of
the houses, while others perished in the fires that were kindled in
most of the towns, particularly in Oppido, where the flames were
fed by great magazines of oil. Not a few, especially among the
peasantry dwelling in the country, were suddenly engulfed in
fissures. Many who were only half buried in the ruins, and who
might have been saved had there been help at hand, were left to die
a lingering death from cold and hunger. Four Augustine monks at
Terranuova perished thus miserably. Having taken refuge in a
vaulted sacristy, they were entombed in it alive by the masses of
rubbish, and lingered for four days, during which their cries for
help could be heard, till death put an end to their sufferings.

Of still more thrilling interest was the case of the Marchioness
Spastara. Having fainted at the moment of the first great shock,
she was lifted by her husband, who, bearing her in his arms,
hurried with her to the harbor. Here, on recovering her senses,
she observed that her infant boy had been left behind. Taking
advantage of a moment when her husband was too much occupied to
notice her, she darted off and, running back to the house, which
was still standing, she snatched her babe from its cradle. Rushing
with him in her arms towards the staircase, she found the stair had
fallen--cutting off all further progress in that direction. She
fled from room to room, pursued by the falling materials, and at
length reached a balcony as her last refuge. Holding up her
infant, she implored the few passers-by for help; but they all,
intent on securing their own safety, turned a deaf ear to her
cries. Meanwhile the mansion had caught fire, and before long the
balcony, with the devoted lady still grasping her darling, was
hurled into the devouring flames.

CHAPTER XVII.

The Charleston and Other Earthquakes of the United States.

The twin continents of America have rivalled the record of the Old
World in their experience of earthquakes since their discovery in
1492. The first of these made note of was in Venezuela in 1530,
but they have been numerous and often disastrous since. Among them
was the great shock at Lima in 1746, by which 18,000 were killed,
and those at Guatemala in 1773, with 33,000, and at Riobamba in
1797, with 41,000 victims. It will, however, doubtless prove of
more interest to our readers if we pass over these ruinous
disasters and confine ourselves to the less destructive earthquakes
which have taken place within our own country.

The United States, large a section of North America as it occupies,
is fortunate in being in a great measure destitute of volcanic
phenomena, while destructive earthquakes have been very rare in its
history. This, it is true, does not apply to the United States as
it is, but as it was. It has annexed the volcano and the
earthquake with its new accessions of territory. Alaska has its
volcanoes, the Philippines are subject to both forms of convulsion,
and in Hawaii we possess the most spectacular volcano of the earth,
while the earthquake is its common attendant. But in the older
United States the volcano contents itself with an occasional puff
of smoke, and eruptive phenomena are confined to the minor form of
the geyser.

We are by no means so free from the earthquake. Slight movements
of the earth's surface are much more common than many of us
imagine, and in the history of our land there have been a number of
earth shocks of considerable violence. Prior to that of San
Francisco, the most destructive to life and property was that of
Charleston in 1886, though the 1812 convulsion in the Mississippi
Valley might have proved a much greater calamity but for the fact
that civilized man had not then largely invaded its centre of
action.

As regards the number of earth movements in this country, we are
told that in New England alone 231 were recorded in two hundred and
fifty years, while doubtless many slighter ones were left
unrecorded. Taking the whole United States, there were 364
recorded in the twelve years from 1872 to 1883, and in 1885 fifty-
nine were recorded, more than two-thirds of them being on the
Pacific slope. Most of these, however, were very slight, some of
them barely perceptible.

Confining ourselves to those of the past important in their
effects, we shall first speak of the shocks which took place in New
England in 1755, in the year and month of the great earthquake at
Lisbon. On the 18th of November of that year, while the shocks at
Lisbon still continued, New England was violently shaken, loud
underground explosive noises accompanying the shocks. In the
harbors along the Atlantic coast there was much agitation of the
waters and many dead fish were thrown up on the shores. The shock,
indeed, was felt far from the coast, by the crew of a ship more
than two hundred miles out at sea from Cape Ann, Massachusetts.

This event, however, was of minor importance, being much inferior
to that of 1812, in which year California and the Mississippi
Valley alike were affected by violent movements of the earth's
crust. The California convulsions took place in the spring and
summer of that year, extending from the beginning of May until
September. Throughout May the southern portion of that region was
violently agitated, the shocks being so frequent and severe that
people abandoned their houses and slept on the open ground. The
most destructive shocks came in September, when two Mission houses
were destroyed and many of their inmates killed. At Santa Barbara
a tidal wave invaded the coast and flowed some distance into the
interior.

It may be said here that California has proved more subject to
severe shocks than any other section of our country. In 1865 sharp
tremors shook the whole region about the Bay of San Francisco, many
buildings being thrown down. Hardly any of brick or stone escaped
injury, though few lives were lost. In 1872 a disturbance was felt
farther west, the whole range of the Sierra Nevada mountains being
violently shaken and the earth tremblings extending into the State
of Nevada. The centre of activity was along the crest of the
range, and immense quantities of rock were thrown down from the
mountain pinnacles. A tremendous fissure opened along the eastern
base of the mountain range for forty miles, the land to the west of
the opening rising and that to the east sinking several feet. One
small settlement, that of Lone Pine, in Owen's Valley, on the east
base of the mountains, was completely demolished, from twenty to
thirty lives being lost. Luckily, the region affected had very few
inhabitants, or the calamity might have been great.

The earthquakes of 1812 in the Mississippi Valley began in
December, 1811, and continued at intervals until 1813. As a rule
they were more distinguished by frequency than violence, though on
several occasions they were severe and had marked effects. They
extended through the valleys of the Mississippi, Arkansas and Ohio,
and their long continuance was remarkable in view of the territory
affected being far from any volcanic region.

The surface of the valley of the Mississippi was a good deal
altered by these convulsions--several new lakes being formed, while
others were drained. Several new islands were also raised in the
river, and during one of the shocks the ground a little below New
Madrid was for a short time lifted so high as to stop the current
of the Mississippi, and cause it to flow backward. The ground on
which this town is built, and the bank of the river for fifteen
miles above it, subsided permanently about eight feet, and the
cemetery of the town fell into the river. In the neighboring
forest the trees were thrown into inclined positions in every
direction, and many of their trunks and branches were broken. It
is affirmed that in some places the ground swelled into great
waves, which burst at their summits and poured forth jets of water,
along with sand and pieces of coal, which were tossed as high as
the tops of trees. On the subsidence of these waves, there were
left several hundreds of hollow depressions from ten to thirty
yards in diameter, and about twenty feet in depth, which remained
visible for many years afterward. Some of the shocks were
vertical, and others horizontal, the latter being the most
mischievous. These earthquakes resulted in the general subsidence
of a large tract of country, between seventy and eighty miles in
length from north to south, and about thirty miles in breadth from
east to west. Lakes now mark many of the localities affected by
the earthquake movements. It is only to the fact that this country
was then very thinly settled that a great loss of life was avoided.

New Madrid, Missouri, was a central point of this earthquake, the
shocks there being repeated with great frequency for several
months. The disturbance of the earth, however, was not confined to
the United States, but affected nearly half of the western
hemisphere, ending in the upheaval of Sabrina in the Azores,
already described. The destruction of Caracas, Venezuela, with
many thousands of its inhabitants, and the eruption of La Soufriere
volcano of St. Vincent Island were incidents of this convulsion.
Dr. J. W. Foster tells us that on the night of the disaster at
Caracas the earthquake grew intense at New Madrid, fissures being
opened six hundred feet long by twenty broad, from which water and
sand were flung to the height of forty feet.

The most destructive of earthquakes in our former history was that
which visited Charleston, South Carolina, in 1886, the injury
caused by it being largely due to the fact that it passed through a
populous city. As it occurred after many of the people had
retired, the confusion and terror due to it were greatly augmented,
people fleeing in panic fear from the tumbling and cracking houses
to seek refuge in the widest streets and open spaces.

South Carolina had been affected by the wide-spread earthquakes of
1812. These in some cases altered the level of the land, as is
related in Lyell's "Principles of Geology." But the effect then
was much less than in 1886. Several slight tremors occurred in the
early summer of that year, but did not excite much attention. More
distinct shocks were felt on August 27th and 28th, but the climax
was deferred till the evening of August 31st. The atmosphere that
afternoon had been unusually sultry and quiet, the breeze from the
ocean, which generally accompanies the rising tide, was almost
entirely absent, and the setting sun caused a little glow in the
sky.

"As the hour of 9.50 was reached," we are told, "there was suddenly
heard a rushing, roaring sound, compared by some to a train of cars
at no great distance, by others to a clatter produced by two or
more omnibuses moving at a rapid rate over a paved street, by
others again, to an escape of steam from a boiler. It was followed
immediately by a thumping and beating of the earth beneath the
houses, which rocked and swayed to and fro. Furniture was
violently moved and dashed to the floor; pictures were swung from
the walls, and in some cases turned with their backs to the front,
and every movable thing was thrown into extraordinary convulsions.
The greatest intensity of the shock is considered to have been
during the first half, and it was probably then, during the period
of its greatest sway, that so many chimneys were broken off at the
junction of the roof. The duration of this severe shock is thought
to have been from thirty-five to forty seconds. The impression
produced on many was that it could be subdivided into three
distinct movements, while others were of the opinion that it was
one continuous movement, or succession of waves, with the greatest
intensity, as already stated, during the first half of its
duration."

Twenty-seven persons were killed outright, and more than that
number died soon after of their hurts or from exposure; many others
were less seriously injured. Among the buildings, the havoc,
though much less disastrous than has been recorded in some other
earthquakes in either hemisphere, was very great. "There was not a
building in the city which had escaped serious injury. The extent
of the damage varied greatly, ranging from total demolition down to
the loss of chimney tops and the dislodgment of more or less
plastering. The number of buildings which were completely
demolished and levelled to the ground was not great; but there were
several hundreds which lost a large portion of their walls. There
were very many also which remained standing, but so badly shattered
that public safety required that they should be pulled down
altogether. There was not, so far as at present is known, a brick
or stone building which was not more or less cracked, and in most
of them the cracks were a permanent disfigurement and a source of
danger and inconvenience." In some places the railway track was
curiously distorted. "It was often displaced laterally, and
sometimes alternately depressed and elevated. Occasionally several
lateral flexures of double curvature and of great amount were
exhibited. Many hundred yards of track had been shoved bodily to
the south eastward."

The ground was fissured at some places in the city to a depth of
many feet, and numerous "craterlets" were formed, from which sand
was ejected in considerable quantities. These are not uncommon
phenomena, and were due, no doubt, to the squirting of water out of
saturated sandy layers not far below the surface; these being
squeezed between two less pervious beds in the passage of the
earthquake wave. The ejected material in the Charleston earthquake
was ordinary sand, such as might exist in many districts which had
been quite undisturbed by any concussions of the earth.

Captain Dutton made a careful study of the observations collected
by himself and others concerning this earthquake, and came to the
conclusion that the Charleston wave traveled with unusual speed,
for its mean velocity was about 17,000 feet a second. The focus of
the disturbance was also ascertained. Apparently it was a double
one, the two centres being about thirteen miles apart, and the line
joining them running nearly the same distance to the west of
Charleston. The approximate depth of the principal focus is given
as twelve miles, with a possible error of less than two miles; that
of the minor one as roughly eight miles.

The Charleston earthquake was felt as a tremor of more or less
force through a wide area, embracing 900,000 square miles, and
affecting nearly the whole country east of the Mississippi. It is
said that the yield of the Pennsylvania natural gas wells
decreased, and that a geyser in the Yellowstone valley burst into
action after four years of rest. The movement of the earth-wave
was in general north and south, deflected to east and west, and the
snake-like fashion in which rails on the railroad were bent
indicated both a vertical and a lateral force.

This earthquake has been attributed to various causes, but
geological experts think that it was due to a slip in the crust
along the Appalachian Mountain chain. There is a line of weakness
along the eastern slope of this chain, characterized by fissures
and faults, and it was thought that a strain had been gradually
brought to bear upon this through the removal of earth from the
land by rains and rivers and its deposition in thick strata on the
sea-bottom. It is supposed that this variation in weight in time
caused a yielding of the strata and a slip seaward of the great
coastal plain. Professor Mendenhall, however, thinks it was due to
a readjustment of the earth's crust to its gradually sinking
nucleus.

CHAPTER XVIII.

The Volcano and the Earthquake, Earth's Demons of Destruction.

To most of us, dwellers upon the face of the earth, this
terrestrial sphere is quite a comfortable place of residence. The
forces of Nature everywhere and at all times surround us, forces
capable, if loosened from their bonds, of bringing death and
destruction to man and the work of his hands. But usually they are
mild and beneficent in their action, not agents of destruction and
lords of elemental misrule. The air, without whose presence we
could not survive a minute, is usually a pleasant companion, now
resting about us in soft calm, now passing by in mild breezes. The
alternation of summer and winter is to us generally an agreeable
relief from the monotony of a uniform climate. The variation from
sunlight to cloud, from dry weather to rainfall, is equally viewed
as a pleasant escape from the weariness of too great fixity of
natural conditions. The change from day to night, from hours of
activity to hours of slumber, are other agreeable variations in the
events of our daily life. In short, a great pendulum seems to be
swinging above us, held in Nature's kindly hand, and adapting its
movements to our best good and highest enjoyment.

But has Nature,--if we are justified in personifying the laws and
forces of the universe,--has mother Nature really our pleasure and
benefit in mind, or does she merely suffer us to enjoy life like so
many summer insects, until she is in the mood to sweep us like
leaves from her path? It must seem the latter to many of the
inhabitants of the earth, especially to the dwellers in certain
ill-conditioned regions. For all the beneficent powers above named
may at a moment's notice change to destructive ones.

THE WIND IS A DEMON IN CHAINS

The wind, for instance, is a demon in chains. At times it breaks
its fetters and rushes on in mad fury, rending and destroying, and
sweeping such trifles as cities and those who dwell therein to
common ruin. Sunshine and rain are subject to like wild caprices.
The sun may pour down burning rays for weeks and months together,
scorching the fertile fields, drying up the life-giving streams,
bringing famine and misery to lands of plenty and comfort, almost
making the blood to boil in our veins. Its antithesis, the
rainstorm, is at times a still more terrible visitant. From the
dense clouds pour frightful floods, rushing down the lofty hills,
sweeping over fertile plains, overflowing broad river valleys, and,
wherever they go, leaving terror and death in their path. We may
say the same of the alternation of the seasons. Summer, while
looked forward to with joyous anticipation, may bring us only
suffering by its too ardent grasp; and winter, often welcomed with
like pleasurable anticipations, may prove a period of terror from
cold and destitution.

Such is the make-up of the world in which we live, such the
vagaries of the forces which surround us. But those enumerated are
not the whole. Can we say, with a stamp of the foot upon the solid
earth, "Here at least I have something I can trust; let the winds
blow and the rains descend, let the summer scorch and the winter
chill, the good earth still stands firm beneath me, and of it at
least I am sure?"

Who says so speaks hastily and heedlessly, for the earth can show
itself as unstable as the air, and our solid footing become as
insecure as the deck of a ship laboring in a storm at sea. The
powers of the atmosphere, great as they are and mighty for
destruction as they may become, are at times surpassed by those
which abide within the earth, deep laid in the so-called
everlasting rocks, slumbering often through generations, but at any
time likely to awaken in wrath, to lift the earth into quaking
billows like those of the sea, or pour forth torrents of liquid
fire that flow in glowing and burning rivers over leagues of ruined
land. Such is the earth with which we have to deal, such the
ruthless powers of nature that spread around us and lurk beneath
us, such the terrific forces which only bide their time to break
forth and sweep too-confident man from the earth's smiling face.

THE SUBTERRANEAN POWERS

The subterranean powers here spoken of, those we had denominated
earth's demons of destruction, are the volcano and the earthquake,
the great moulding forces of the earth, tearing down to rebuild,
rending to reconstitute, and in this elemental work often bringing
ruin to man's boasted fanes and palaces.

No one who has ever seen a volcano or "burning mountain" casting
forth steam, huge red-hot stones, smoke, cinders and lava, can
possibly forget the grandeur of the spectacle. At night it is
doubly terrible, when the darkness shows the red-hot lava rolling
in glowing streams down the mountain's side. At times, indeed, the
volcano is quiet, and only a little smoke curls from its top. Even
this may cease, and the once burning summit may be covered over
with trees and grass, like any other hill. But deep down in the
earth the gases and pent-up steam, are ever preparing to force
their way upward through the mountain, and to carry with them
dissolved rocks, and the stones which block their passage.
Sometimes, while all is calm and beautiful on the mountains,
suddenly deep-sounding noises are heard, the ground shakes, and a
vast torrent tears its way through the bowels of the volcano, and
is flung hundreds of feet high in the air, and, falling again to
the earth, destroys every living thing for miles around.

It is the same with the earthquake as with the volcano. The
surface of the earth is never quite still. Tremors are constantly
passing onward which can be distinguished by delicate instruments,
but only rarely are these of sufficient force to become noticeable,
except by instrumental means. At intervals, however, the power
beneath the surface raises the ground in long, billow-like motions,
before which, when of violent character, no edifice or human
habitation can for a moment stand. The earth is frequently rent
asunder, great fissures and cavities being formed. The course of
rivers is changed and the waters are swallowed up by fissures rent
in the surface, while ruin impends in a thousand forms. The cities
become death pits and the cultivated fields are buried beneath
floods of liquid mud. Fortunately these convulsions, alike of the
earthquake and volcano, are comparative rarities and are confined
to limited regions of the earth's surface. What do we know of
those deep-lying powers, those vast buried forces dwelling in
uneasy isolation beneath our feet? With all our science we are but
a step beyond the ancients, to whom these were the Titans, great
rebel giants whom Jupiter overthrew and bound under the burning
mountains, and whose throes of agony shook the earth in quaking
convulsions. To us the volcanic crater is the mouth from which
comes the fiery breath of demon powers which dwell far down in the
earth's crust. The Titans themselves were dwarfs beside these
mighty agents of destruction whose domain extends for thousands of
miles beneath the earth's surface and which in their convulsions
shake whole continents at once. Such was the case in 1812, when
the eruption of Mont Soufriere on St. Vincent, as told in a later
chapter, formed merely the closing event in a series of earthquakes
which had made themselves felt under thousands of miles of land.

ANCIENT AWE OF VOLCANOES

In olden times volcanoes were regarded with superstitious awe, and
it would have been considered highly impious to make any
investigation of their actions. We are told by Virgil that Mt.
Etna marks the spot where the gods in their anger buried Enceladus,
one of the rebellious giants. To our myth-making ancestors one of
the volcanoes of the Mediterranean, set on a small island of the
Lipari group, was the workshop of Vulcan, the god of fire, within
whose depths he forged the thunderbolts of the gods. From below
came sounds as of a mighty hammer on a vast anvil. Through the
mountain vent came the black smoke and lurid glow from the fires of
Vulcan's forge. This old myth is in many respects more consonant
with the facts of nature than myths usually are. In agreement with
the theory of its internal forces, the mountain in question was
given the name of Volcano. To-day it is scarcely known at all, but
its name clings to all the fire-breathing mountains of the earth.

As before said, at the present day we are little in advance of the
ancients in actual knowledge of what is going on so far beneath our
feet. We speak of forces where they spoke of fettered giants, but
can only form theories where they formed myths. Is the earth's
centre made up of liquid fire? Does its rock crust resemble the
thick ice crust on the Arctic Seas, or is the earth, as later
scientists believe, solid to the core? Is it heated so fiercely,
miles below our feet, that at every release of pressure the solid
rock bursts into molten lava? Is the steam from the contact of
underground rivers and deep-lying fires the origin of the terrible
rending powers of the volcano's depths? Truly we can answer none
of these questions with assurance, and can only guess and
conjecture from the few facts open to us what lies concealed far
beneath.

RARITY OF ANCIENT ACCOUNTS

In the history of earthquakes nothing is more remarkable than the
extreme fewness of those recorded before the beginning of the
Christian era, in comparison with those that have been registered
since that time. It is to be borne in mind, however, that before
the birth of Christ only a small portion of the globe was inhabited
by those likely to make a record of natural events. The vast
apparent increase in the number of earthquakes in recent times is
owing to a greater knowledge of the earth's surface and to the
spread of civilization over lands once inhabited by savages. The
same is to be said of volcanic eruptions, which also have
apparently increased greatly since the beginning of the Christian
era. There may possibly have been a natural increase in these
phenomena, but this is hardly probable, the change being more
likely due to the increase in the number of observers.

The structure of a volcano is very different from that of other
mountains, really consisting of layers of lava and volcanic ashes,
alternating with each other and all sloping away from the center.
These elevations, in fact, are formed in a different manner from
ordinary mountains. The latter have been uplifted by the influence
of pressure in the interior of the earth, but the volcano is an
immediate result of the explosive force of which we have spoken,
the mountain being gradually built up by the lava and other
materials which it has flung up from below. In this way mountains
of immense height and remarkable regularity have been formed.
Mount Orizabo, near the City of Mexico, for instance, is a
remarkably regular cone, undoubtedly formed in this way, and the
same may be said of Mount Mayon, on the Island of Luzon.

In many cases the irregularity of the volcano is due to subsequent
action of its forces, which may blow the mountain itself to pieces.
In the case of Krakatoa, in the East Indies, for instance, the
whole mountain was rent into fragments, which were flung as dust
miles high into the air. The main point we wish to indicate is
that volcanoes are never formed by ordinary elevating forces and
that they differ in this way from all other mountains. On the
contrary, they have been piled up like rubbish heaps, resembling
the small mountains of coal dust near the mouths of anthracite
mines.

It is to the burning heat of the earth's crust and the influence of
pressure, and more largely to the influx of water to the molten
rocks which lie miles below the surface, that these convulsions of
nature are due. Water, on reaching these overheated strata,
explodes into volumes of steam, and if there is no free vent to the
surface, it is apt to rend the very mountain asunder in its efforts
to escape. Such is supposed to have been the case in the eruption
of Krakatoa, and was probably the case also in the recent case of
Mt. Pelee.

GENERAL DESCRIPTION OF ERUPTIONS

If we should seek to give a general description of volcanic
eruptions, it would be in some such words as follows: An eruption
is usually preceded by earthquakes which affect the whole
surrounding country, and associated with which are underground
explosions that seem like the sound of distant artillery. The
mountain quivers with internal convulsions, due to the efforts of
its confined forces to find an opening. The drying up of wells and
disappearance of springs are apt to take place, the water sinking
downward through cracks newly made in the rocks. Finally the
fierce unchained energy rends an opening through the crater and an
eruption begins. It comes usually with a terrible burst that
shakes the mountain to its foundation; explosions following rapidly
and with increasing violence, while steam issues and mounts upward
in a lofty column. The steam and escaping gases in their fierce
outbreaks hurl up into the air great quantities of solid rock torn
from the sides of the opening. The huge blocks, meeting each other
in their rise and fall, are gradually broken and ground into minute
fragments, forming dust or so-called ashes, often of extreme
fineness, and in such quantities as frequently to blot out the
light of the sun. There is another way in which a great deal of
volcanic dust is made; the lava is full of steam, which in its
expansion tears the molten rock into atoms, often converting it
into the finest dust.

The eruption of Mt. Skaptar, in Iceland, in 1783, sent up such
volumes of dust that the atmosphere was loaded with it for months,
and it was carried to the northern part of Scotland, 600 miles
away, in such quantities as to destroy the crops. During the
eruption of Tomboro, in the East Indies, in 1815, so great was the
quantity of dust thrown up that it caused darkness at midday in
Java 300 miles away and covered the ground to a depth of several
inches. Floating pumice formed a layer on the ocean surface two
and a half feet in thickness, through which vessels had difficulty
in forcing their way.

The steam which rises in large volumes into the air may become
suddenly condensed with the chill of the upper atmosphere and fall
as rain, torrents of which often follow an eruption. The rain,
falling through the clouds of volcanic dust, brings it to the earth
as liquid mud, which pours in thick streams down the sides of the
mountain. The torrents of flowing mud are sometimes on such a
great scale that large towns, as in the instance of the great city
of Herculaneum, may be completely buried beneath them. Over this
city the mud accumulated to the depth of over 70 feet. In addition
to these phenomena, molten lava often flows from the lip of the
crater, occasionally in vast quantities. In the Icelandic eruption
of 1783 the lava streams were so great in quantity as to fill river
gorges 600 ft. deep and 200 ft. wide, and to extend over an open
plain to a distance of 12 to 15 miles, forming lakes of lava 100
feet deep. The volcanoes of Hawaii often send forth streams of
lava which cover an area of over 100 square miles to a great depth.

GREAT OUTFLOWS OF LAVA

In the course of ages lava outflows of this kind have built up in
Hawaii a volcanic mountain estimated to contain enough material to
cover the whole of the United States with a layer of rock 50 feet
deep. These great outflows of lava are not confined to mountains,
but take place now and then from openings in the ground, or from
long cracks in the surface rocks. Occasionally great eruptions
have taken place beneath the ocean's surface, throwing up material
in sufficient quantity to form new islands.

The formation of mud is not confined to the method given, but great
quantities of this plastic material flow at times from volcanic
craters. In the year 1691 Imbaburu, one of the peaks of the Andes,
sent out floods of mud which contained dead fish in such abundance
that their decay caused a fever in the vicinity. The volcanoes of
Java have often buried large tracts of fertile country under
volcanic mud.

An observation of volcanoes shows us that they have three well
marked phases of action. The first of these is the state of
permanent eruption, as in case of the volcano of Stromboli in the
Mediterranean. This state is not a dangerous one, since the steam,
escaping continually, acts as a safety valve. The second stage is
one of milder activity with an occasional somewhat violent
eruption; this is apt to be dangerous, though not often very
greatly so. The safety valve is partly out of order. The third
phase is one in which long periods of repose, sometimes lasting for
centuries, are followed by eruptions of intense energy. These are
often of extreme violence and cause widespread destruction. In
this case the safety valve has failed to work and the boiler
bursts.

OFTEN REST FOR LONG TERMS OF YEARS

Such are the general features of action in the vast powers which
dwell deep beneath the surface, harmless in most parts of the
earth, frightfully perilous in others. Yet even here they often
rest for long terms of years in seeming apathy, until men gather
above their lurking places in multitudes, heedless or ignorant of
the sleeping demons that bide their time below. Their time is sure
to come, after years, perhaps after centuries. Suddenly the solid
earth begins to tremble and quake; roars as of one of the buried
giants of old strike all men with dread; then, with a fierce
convulsion, a mountain is rent in twain and vast torrents of steam,
burning rock, and blinding dust are hurled far upward into the air,
to fall again and bury cities, perhaps, with all their inhabitants
in indiscriminate ruin and death.

CHAPTER XIX.

Theories of Volcanic and Earthquake Action.

Though the first formation of a volcano (Italian, vulcano, from
Vulcan, the Roman god of fire) has seldom been witnessed, it would
seem that it is marked by earthquake movements followed by the
opening of a rent or fissure; but with no such tilting up of the
rocks as was once supposed to take place. From this fissure large
volumes of steam issue, accompanied by hydrogen, nitrogen, carbon
dioxide, hydrochloric acid, and sulphur dioxide. The hydrogen,
apparently derived from the dissociation of water at a high
temperature, flashes explosively into union with atmospheric
oxygen, and, having exerted its explosive force, the steam
condenses into cloud, heavy masses of which overhang the volcano,
pouring down copious rains. This naturally disturbs the electrical
condition of the atmosphere, so that thunder and lightning are
frequent accompaniments of an eruption. The hydrochloric acid
probably points to the agency of sea-water. Besides the gases just
mentioned, sulphuretted hydrogen, ammonia and common salt occur;
but mainly as secondary products, formed by the union of the vapors
issuing from the volcano, and commonly found also in the vapors
rising from cooling lava streams or dormant volcanic districts. It
is important to notice that the vapors issue from the volcano
spasmodically, explosions succeeding each other with great rapidity
and noise.

All substances thrown out by the volcano, whether gaseous, liquid
or solid, are conveniently united under the term ejectamenta
(Latin, things thrown out), and all of them are in an intensely
heated, if not an incandescent state. Most of the gases are
incombustible, but the hydrogen and those containing sulphur burn
with a true flame, perhaps rendered more visible by the presence of
solid particles. Much of the so-called flame, however, in popular
descriptions of eruptions is an error of observation due to the
red-hot solid particles and the reflection of the glowing orifice
on the over-hanging clouds.

ENORMOUS FORCE DISPLAYED

Solid bodies are thrown into the air with enormous force and to
proportionally great heights, those not projected vertically
falling in consequence at considerable distances from the volcano.
A block weighing 200 tons is said to have been thrown nine miles by
Cotopaxi; masses of rock weighing as much as twenty tons to have
been ejected by Mount Ararat in 1840; and stones to have been
hurled to a distance of thirty-six miles in other cases. The solid
matter thrown out by volcanoes consists of lapilli, scoriae, dust
and bombs.

Though on the first formation of the volcano, masses of non-
volcanic rock may be torn from the chimney or pipe of the mountain,
only slightly fused externally owing to the bad conducting power of
most rocks, and hurled to a distance; and though at the beginning
of a subsequent eruption the solid plug of rock which has cooled at
the bottom of the crater, or, in fact, any part of the volcano, may
be similarly blown up, the bulk of the solid particles of which the
volcano itself is composed is derived from the lake of lava or
molten rock which seethes at the orifice. Solid pieces rent from
this fused mass and cast up by the explosive force of the steam
with which the lava is saturated are known as lapilli. Cooling
rapidly so as to be glassy in texture externally, these often have
time to become perfectly crystalline within.

Gases and steam escaping from other similar masses may leave them
hollow, when they are termed bombs, or may pit their surfaces with
irregular bubble-cavities, when they are called scoriae or
scoriaceous. Such masses whirling through the air in a plastic
state often become more or less oblately spheroidal in form; but,
as often, the explosive force of their contained vapors shatters
them into fragments, producing quantities of the finest volcanic
dust or sand. This fine dust darkens the clouds overhanging the
mountain, mixes with the condensed steam to fall as a black mud-
rain, or lava di aqua (Italian, water lava), or is carried up to
enormous heights, and then slowly diffused by upper currents of the
atmosphere. In the eruption of Vesuvius of A.D. 79, the air was
dark as midnight for twelve or fifteen miles round; the city of
Pompeii was buried beneath a deposit of dry scoriae, or ashes and
dust, and Herculaneum beneath a layer of the mud-like lava di aqua,
which on drying sets into a compact rock. Rocks formed from these
fragmentary volcanic materials are known as tuff.

VOLCANIC CONES HAVE SIMILAR CURVATURES

It is entirely of these cindery fragments heaped up with marvellous
rapidity round the orifice that the volcano itself is first formed.
It may, as in the case of Jorullo in Mexico in 1759, form a cone
several hundred feet high in less than a day. Such a cone may have
a slope as steep as 30 or 40 degrees, its incline in all cases
depending simply on the angle of repose of its materials; the
inclination, that is, at which they stop rolling. The great
volcanoes of the Andes, which are formed mainly of ash, are very
steep. Owing to a general similarity in their materials, volcanic
cones in all parts of the world have very similar curvatures; but
older volcanic mountains, in which lava-streams have broken through
the cone, secondary cones have arisen, or portions have been blown
up, are more irregular in outline and more gradual in inclination.

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

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