resolves itself into a volcanic crater with an inner cone, as every active volcano has. It is rather ludicrous to suppose that polyps, among the lowest of created beings, leading an ephemeral existence, should yet have such unanimity of purpose, such perfect mutual understanding, as to undertake to build their reefs in a more or less circular form; it is preposterous to suppose the unvarying form of the structure is the result of mere chance. Clearly we must find some other influences; and the most reasonable is to suppose the foundations of these islands were laid by the same agency that raised all other Oceanic islands from the bed of the sea.
The volcano thus plays an important part in the earth’s economy. Not only does it add to land areas by upheaval from the deep. The amount of material thrown out by the Javanese volcanoes alone during the past hundred years is greater far than all the silt borne to the sea by American rivers during the same period. Krakatoa, in its recent eruption, threw out more than the Mississippi bears to the sea in sixty years.
There is some doubt as to how much volcanoes effect by direct upheaval. The formation of many observed cones shows that the majority are mainly built up by the materials thrown out, and not by any great elevation of the adjacent surface. In the case of a volcano already existing, it is of course not easy to know what proportion of its mass is merely accumulation of lava, cinders, or tufa.
As to the form of volcanic cones, those of ashes, cinders, and scoria are of course steepest; those of lava thrown out when liquid having a very gradual slope. The difference may be readily illustrated by comparing a heap of sand and pebbles with a heap of stiffening molasses candy. One is steeply conical; the other, rounded or dome-like. But either form of volcano may abound in crevices and apertures from which issue sulphurous vapors and gases. These fumaroles, as they are called, are usually surrounded with mineral deposits, often resembling the most delicate filigree work.
Having considered the general phases and principles of volcanic action, we may now notice some of the more famous eruptions of the past.
CHAPTER XXI.
GREAT ERUPTIONS OF VESUVIUS.
“E’en while they cheered the gladiator’s thrust,
And shouted as the lion crunched his bones,
Up sprang the Fire King from his ages’ sleep
Shook wide his robe of ever-deepening night,
And flung his fiery banner on the wind.
The groaning earth then trembled at his tread,
And thousand thunders rent the raging mount,
While prince and pauper, ’mid the scorching gloom,
Groped through the gaping streets; the ocean hissed,
And palaces and marble temples reeled,
And crushed or prisoned; still the ashes fell,
Till mansions, statues, homes and colonnades,
And Strength, and Beauty, Love, and Life, and Death,
Lay heaps on heaps, in one black ruin blent.”
OR nearly seventeen hundred years there lay beneath a sea of ashes near the Naples Bay, a city whose destruction had not been described by the younger Pliny; and in the lapse of years its site had been forgotten. During the construction of an aqueduct in 1592, workmen frequently came upon foundations of buildings. No curiosity seems to have been aroused. Nearly a hundred years later other buildings were discovered, with the inscription “Pompeii.” Still there was no practical interest. Then the attention of the learned was drawn to the discoveries at Herculaneum; and Alcubierre, a Spanish colonel of engineers, in examining the subterranean canal, was led by the discovery of a house and statues to conjecture that some great treasures might lie buried there. Obtaining permission of the King of Naples, he began excavations in the year 1748. In a few days he unearthed “a picture eleven palms long by four and one-half high, containing festoons of eggs, fruits and flowers, the head of a man, large and in good style, a helmet, an owl, various small birds and other objects.” Then was found the skeleton of a man, covered with the lava mud. By his side were eighteen brass coins and one of silver. Then was found an amphitheatre, with a seating capacity of ten thousand. But the work was poorly conducted: valuable pictures were detached from the walls, and the buildings again covered with rubbish. No strangers were allowed to copy anything.
When the French occupied Naples, the work was for a time better conducted; then it again declined. When Victor Emmanuel became King of Italy, a distinguished antiquarian scholar, Guiseppe Fiorelli, was appointed director-general of the works. Since then, the work has been well done, Signor Fiorelli noting “every appearance or fragment which might afford or suggest a restoration of any part of a buried edifice; replacing with fresh timbers every charred beam, propping every tottering wall or portion of brick work,” till the tourist sees to-day a town in the integrity of its outlines and order of its arrangement. “Temples, baths, markets, tombs, stand out just as they stood eighteen hundred years ago. The villa of the port, the forum, the counting-house, the baker’s shop, the school-room, the kitchen, carry us into the very heart of Roman life in the brightest days of the empire. The jewelry of beauty, the spade of the laborer, the fetter of the prisoner and the weapon of the soldier are all there, reproducing and realizing the past with a vividness which can scarcely be conceived.”