In all great eruptions the flow of the lava is preceded by the ejection of vast quantities of volcanic dust, ashes, dross, slag, and loose stones. These are tossed into the air with tremendous violence, consequently, to a great height. The stones thus ejected are sometimes of immense size. A rock, whose weight is estimated at two hundred tons, was thrown from the summit of Cotopaxi to the distance of more than ten miles. Large stones have been tossed up by Vesuvius to the estimated height of three thousand six hundred feet. The dust of the volcano of St. Vincent was carried more than two hundred miles to the eastward in the teeth of the trade wind; consequently it must have been thrown to an enormous height, in order to its falling at so vast a distance from its source.
Besides the usual volcanic dust and ashes, there is sometimes thrown from the crater of a volcano a substance resembling spun-glass or asbestos. It possesses the flexibility and lustre of silk. The volcano of Salazes, in the Island of Bourbon, is remarkable for this substance, and it has there been seen to form a cloud covering the entire surface of the mountain. But it has also been found in other places. How curious it would be to have this volcanic silk spun into threads, and knitted into stockings or woven into a garment! Who can tell what may happen in these days of adventure and invention? Who knows but what some young reader, whose eye is now resting on this page, may yet live to present his ladylove with a pair of knitted gloves composed of the volcanic silk of Salazes?
Great as the contrast is between this filmy material and the ponderous blocks tossed into the air by Cotopaxi and Etna, it is not greater than that between the latter and other masses which have from time to time been upheaved by volcanic forces. Instances have occurred of whole islands having been raised from the bed of the ocean, or whole mountains upreared on the surface of the land, far away from the sea, and that too in the short space of a few hours. But of such we shall have occasion to speak more at large in the sequel.
Of all the extraordinary productions that have ever been thrown up by volcanoes, the strangest of all are fishes. How droll to dine upon fish cooked in a volcano! A queer fish it must be that likes to dwell in the bowels of a mountain—more especially of one whose entrails are mostly of liquid fire. But of this also more fully anon.
In addition to the solid materials thrown out by volcanoes, there are sometimes poured forth torrents of boiling water and liquid mud. More frequently, however, the water issues in the form of vast columns of steam and sulphurous vapour. These ascend to great heights in the air, and becoming gradually chilled, they form immense masses of dark heavy clouds, similar to those we observe before a thunderstorm. Nor is this resemblance apparent only. For the clouds that overhang an active volcano during an eruption of its vapours are, in reality, thunderclouds highly charged with electricity. They accordingly produce what Baron Humboldt calls the volcanic storm. It includes all the most terrible of atmospheric phenomena—lightnings of extraordinary vividness; thunders that peal and reverberate as if they would rend the echoes asunder; torrents of rain that pour down upon the mountain and its neighbourhood, hissing like thousands of serpents when they fall on the glowing lava-torrent; and whirlwinds that sweep the volcanic ashes round and round in vast eddies, and before whose violence no man of mortal mould is able for a moment to stand.
Beyond and above this din of contending elements are heard the hoarse bellowings of the mountain itself, which, meanwhile, trembles to its very core. The detonations from the volcano far exceed in loudness any other earthly noise. Compared with these, the pealing of the loudest thunder is but as the report of a musket contrasted with the simultaneous discharge of a thousand pieces of heavy ordnance. The explosions of Tomboro, and the vibrations accompanying them, have been heard and felt at almost incredible distances. Judge, then, of the immensity of the forces which are thus brought into play, and the overwhelming grandeur of the scene which such an eruption, with all its accompaniments of storm and tempest, must present to the bewildered eye and ear. Even to read of it sends a thrill through the nerves: what, then, must it be to listen and behold?
So far do we dwell from the nearest volcanoes, and so little are we familiar with the names except of a few, that not many persons are aware of the large number of burning mountains on the face of our globe. The total number, however, of those which are known to have been active within historic times is fully two hundred. Of these, the most familiar to us for its classic fame and its restless activity is Mount Vesuvius, which stands alone in its grandeur on the continent of Europe. The most violent in its activity is Tomboro, in the island of Sumbáwa. The highest is Cotopaxi, in the range of the Andes, which rises far into the region of perpetual snow. Its height is 16,800 feet above the level of the sea. Strange it seems, that volcanic fires should glow at such a height in the midst of snow and ice. But in this particular Cotopaxi does not stand alone. The Peak of Teneriffe, Mount Etna, and several others, also rise above the snow-line; while the burning mountains of Iceland, Greenland, and Kamtschatka, with those which rear their heads in the frozen regions near the South Pole, are for the most part enveloped in ice and snow from head to foot.
Before proceeding to describe to you some of the more interesting of the individual volcanoes and volcanic groups, it may be well to let you into a secret worth knowing. You would doubtless like to have a volcano all to yourself. Here is the receipt: Buy several pounds of clean iron filings, and a somewhat larger quantity of the flowers of sulphur. Mix the two together and knead them well with water into a stiffish paste. Then wrap this pudding in a cloth, and put another cloth about it, which has been smeared with common or coal-tar. Dig a hole in some quiet corner of your garden, pop your dumpling into it, and cover it well up with earth, treading it down firmly with your feet. Not many hours will elapse before you will see the ground swell like a molehill; an eruption will ensue, and you will be the happy possessor of a Stromboli of your own!
CHAPTER II
Volcanoes of Iceland—Mount Hecla—Earliest Eruption—Great Eruption in 1845—Skaptàr Yökul—Terrible Eruption in 1783—Rise and Disappearance of Nyoë—Katlugaia—The Geysers—A very hot Bath —Californian Geysers—Iceland-spar—Jan Mayen
We shall begin with the volcanoes of Iceland, of which the most interesting and active is Mount Hecla. The annexed woodcut will give you an idea of its appearance. You will observe the column of volcanic vapour ascending from the snow-clad summit of the cone, and how dreary and desolate is the aspect of the country at its base.
The earliest recorded eruption of Mount Hecla took place in the ninth century of the Christian era; but probably there had been many before that date. Since then there have been between twenty and thirty considerable eruptions of this mountain, and it has sometimes remained in a state of activity for upwards of six years with little intermission. It took a long rest, however, of more than sixty years' duration, prior to the year 1845, when it again burst forth. After a violent storm on the night of the 2nd of September in that year, the surface of the ground in the Orkney Islands was found strown with volcanic dust. There was thus conveyed to the inhabitants of Great Britain an intimation that Hecla had been again at work. Accordingly, tidings soon after arrived of a great eruption of the mountain. On the night of the 1st of September, the dwellers in its neighbourhood were terrified by a fearful underground groaning, which continued till mid-day on the 2nd. Then, with a tremendous crash, there were formed in the sides of the cone two large openings, whence there gushed torrents of lava, which flowed down two gorges on the flanks of the mountain. The whole summit was enveloped in clouds of vapour and volcanic dust. The neighbouring rivers became so hot as to kill the fish, and the sheep fled in terror from the adjoining heaths, some being burnt before they could escape.
On