Wonders of Creation.

by Anonymous.

PREFACE

Being intended for the Young, this work treats of Volcanoes only in a popular way. Scientific details and philosophical speculations are accordingly avoided. Nevertheless, a perusal of the following pages may so stimulate the curiosity of youthful minds, that some, on attaining to riper years and more mature understanding, may be inspired with a longing to inquire more deeply into this interesting subject. They may be stimulated to investigate, in a philosophical spirit, all the marvellous facts and phenomena connected with volcanic agency, and to speculate on their causes and modes of operation. Some also, on reaching their manhood, may be induced to ascend one or more of the nearer active volcanoes, and examine their phenomena for themselves. The facilities of travel are now so great, that a visit to Vesuvius or Etna is no longer beyond the limits of a holiday trip. Even the more remote Hecla with the playful Geysers may be reached within a reasonable time. Perhaps a very few, who are now scientific travellers in embryo, may call to remembrance what they may have read in these pages, when, many years hence, they may be climbing the cone of Cotopaxi, or peering into the crater of Kilauea.

Apart from these considerations, a perusal of this work may enable the young mind to form a more lively idea of the tremendous energy of the forces which are imprisoned in the bowels of the earth. Such a vivid conception will naturally lead to a higher appreciation of the wisdom and power of Him who guides the operation of those forces by his laws, and has set bounds to their activity which they cannot overpa.s.s.

CHAPTER I.

Volcanoes in general--Origin of the Name--General Aspect--Crater--Cone--Subordinate Cones and Craters--Peak of Teneriffe--Lava-Streams--Cascades and Jets of Lava--Variations in its Consistency--Pumice--Different Sorts of Lava--Obsidian--Olivine--Sulphur--Dust, Ashes, &c.--Volcanic Silk--Volcanic Islands--Volcanic Fishes--Hot Water, Mud, Vapours, &c--Volcanic storm--Explosions--Number of Volcanoes--King of the Volcanoes--Artificial Volcano.

Among the many wonderful works of G.o.d, none exhibits so much of awful grandeur as an active volcano. This name for a burning mountain was first applied to that which exists in the island anciently called Hiera, one of the Lipari group. It is derived from the name of the heathen G.o.d Vulcan, which was originally spelt with an initial B, as appears from an ancient altar on which were inscribed the words BOLCANO SAC. ARA. This spelling indicates the true derivation of the name, which is simply a corruption of Tubal-cain, who was "an instructer of every artificer in bra.s.s and iron"

(Gen. iv. 22). The ancient heathen, having deified this personage, imagined, on first seeing a burning mountain, that Tubal-cain, or Vulcan, must have established his forge in the heart of it, and so, not unnaturally, named it Volcano--an appellation which the Island of Hiera retains to the present day.

The Cyclops--the supposed descendants of Vulcan, who were fabled to have been of gigantic stature, and to have had each only one eye in the centre of the forehead--were imagined to be the workmen who laboured in these underground forges. The noises, proceeding from the heart of the mountain, were attributed to their operations. It is to the Island of Hiera that Virgil alludes in the aeneid, lib.

viii. 416. The pa.s.sage is thus rendered by Dryden:--

"Sacred to Vulcan's name, an isle there lay, Betwixt Sicilia's coasts and Lipare, Raised high on smoking rocks, and deep below, In hollow caves the fires of Etna glow.

The Cyclops here their heavy hammers deal; Loud strokes and hissings of tormented steel Are heard around; the boiling waters roar, And smoky flames through fuming tunnels soar."

A volcano generally presents itself to the imagination as a mountain sending forth from its summit great clouds of smoke with vast sheets of flame, and it is not unfrequently so described. The truth is, however, that a real volcano seldom emits either true smoke or true flame. What is mistaken for smoke consists merely of vast volumes of fine dust, mingled with much steam and other vapours--chiefly sulphurous. What appears like flames is simply the glare from the glowing materials which are thrown up towards the top of the mountain--this glare being reflected from the clouds of dust and steam.

[Ill.u.s.tration: Peak of Teneriffe.]

The most essential part of a volcano is the crater, a hollow basin, generally of a circular form. It is often of large dimensions, and sometimes of vast depth. Some volcanoes consist of a crater alone, with scarcely any mountain at all; but in the majority of cases the crater is situated on the top of a mountain, which in some instances towers to an enormous height. The part of the mountain which terminates in the princ.i.p.al crater is usually of a conical form--much like a gla.s.s-house chimney, and is therefore named the cone. It is generally composed of loose ashes and cinders, with here and there ma.s.ses of stone, which have been tossed into the air by the volcanic forces. In some mountains the cone rises out of a hollow at a considerable height from the base. A hollow of this kind is generally regarded as having been a former crater, which had become extinct before the existing cone was raised. There are sometimes formed lower down the mountain subordinate craters, smaller than that which occupies the summit of the cone. Within the crater itself there are frequently numerous little cones, from which vapours are continually issuing, with occasional volleys of ashes and stones.

One of the largest and most perfect of the volcanic cones in the world is that of the Peak of Teneriffe, of which you have here a representation. It conveys a good idea of the general form of the cone, and has long been a conspicuous and useful landmark to mariners. It is upwards of twelve thousand feet in height, and is said to be visible in very clear weather at a distance of a hundred miles.

The most interesting products of an active volcano are the streams of lava which it pours forth--sometimes from the princ.i.p.al crater on the summit--sometimes from the smaller craters lower down. This lava consists of melted stone. When it issues from the mountain its heat is intense and it glows like a furnace, so that, during the night especially, these fiery rivers present a grand yet awful spectacle. The streams spread themselves till they sometimes attain a breadth of several miles, with a depth of several hundred feet, and they flow onward till their length sometimes reaches fifty miles.

Lava, not being so liquid as water, does not flow so rapidly: nevertheless, when it is careering down the sides of a mountain, or where the slope of the ground is considerable, it advances with great speed. Even when at its hottest, it is somewhat viscid, like treacle, and this viscidness increases as it cools. Hence on a level plain, and at some distance from its source, the lava-stream advances at a leisurely pace. In such circ.u.mstances the cooling proceeds so quickly that a crust of considerable thickness is soon formed on the top of the current, and persons who are bold enough may cross the stream by means of this natural bridge. Even where the current continues flowing rapidly, this crust may be formed on its surface; and a man, whose curiosity exceeds his prudence, may stand on the top of it, bore a hole through the crust, and see the lava flowing underneath his feet!

Nothing can resist the progress of the lava-flood; trees, houses, everything yields to its ma.s.sive a.s.sault, The trees take fire before its approach, and when it reaches them they emit a hissing noise almost amounting to a shriek, and then plunging into the molten flood are seen no more. Even the sea cannot withstand the lava-stream, but retires on its approach; so that promontories stretching to a considerable distance from the sh.o.r.e are formed in this manner, when the molten matter hardens into stone.

The eruptions of lava are sometimes attended by peculiarities which impart to them much additional grandeur. Instances have occurred in which the fiery stream has plunged over a sheer precipice of immense height, so as to produce a glowing cascade exceeding in breadth and perpendicular descent the celebrated Falls of Niagara.

In other cases, the lava, instead of at once flowing down the sides of the mountain, has been first thrown up into the air as a fiery fountain several hundred feet in height. This happens when the great crater at the summit of the cone is full of liquid lava but does not overflow. Then, on the formation of an opening in the side of the cone, a good way down, the lava issuing from it is projected upwards to nearly the same height that it occupies in the interior of the crater at the top of the cone. It is hardly possible for the fancy to picture to itself anything so magnificent as such a fountain of liquid fire must be. A simple jet of water of considerable volume, thrown into the air to the height of a hundred feet, is itself a beautiful spectacle. What then must be a huge jet of glowing white lava projected to the height of several hundred feet, and with what an awful thundering sound must it come tumbling to the ground, thence to rush as a roaring torrent down the mountain's side!

Lava, when congealed, differs in its consistency according as it is near the top or near the bottom of the stream. When near the top it is porous, owing to its rapid cooling; when near the bottom it is dense, owing to its slow cooling and the great pressure to which it is subjected. When the lighter superficial lava is brought suddenly into contact with water, as when a lava-stream enters the sea, it becomes still lighter and more porous--forming the well-known substance called pumice, so much used for polishing. It may be regarded as the solidified froth of lava, and is so light that it floats on the surface of water.

The lavas of different mountains, when cooled and hardened, differ much in their appearance and composition. Among those of Iceland is found the beautiful black volcanic gla.s.s named obsidian. It is a good deal used for ornamental purposes; for it possesses the peculiar property of presenting a different appearance according to the manner in which it is cut. When cut in one direction it is of a beautiful jetty black; when cut across that direction it is glistering gray. The lavas of Vesuvius are generally of a brown colour, and are also used in the arts. In them are found the beautiful olive-green crystals of the mineral called olivine, sometimes used by jewellers. But the most useful of all volcanic productions is native sulphur, in which Mount Etna has been very prolific. It is to this mountain chiefly, therefore, that we are indebted for our beautiful fire-works--our squibs, crackers, Roman candles, serpents, Catherine-wheels, and sky-rockets. Would it had produced nothing more harmful than these! But it has also supplied one of the ingredients of that villainous gunpowder, which has been the means of thrusting so many of our fellow-creatures prematurely out of the world. Etna, however, can hardly be held responsible for this sad misuse of the valuable substance which it affords; while even gunpowder itself has, on the whole, been of vast benefit to mankind. Could we only refrain from shooting each other with it, we might regard it as an almost unmixed good; for it has helped us greatly in forming our roads, railways, and tunnels, and in working our quarries and mines.

In all great eruptions the flow of the lava is preceded by the ejection of vast quant.i.ties 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-gla.s.s or asbestos. It possesses the flexibility and l.u.s.tre 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 ma.s.ses 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 s.p.a.ce 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 ma.s.ses 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 hoa.r.s.e 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 cla.s.sic 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 Sumbawa. 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 quant.i.ty 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--Skaptar Yokul--Terrible Eruption in 1783--Rise and Disappearance of Nyoe--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 the night of the 15th of September, two new openings were formed--one on the eastern, and the other on the southern slope--from both of which lava was discharged for twenty-two hours. It flowed to a distance of upwards of twenty miles, killing many cattle and destroying a large tract of pasturage. Twelve miles from the crater, the lava-stream was between forty and fifty feet deep and nearly a mile in width. On the 12th of October a fresh torrent of lava burst forth, and heaped up another similar ma.s.s. The mountain continued in a state of activity up to April 1846; then it rested for a while, and began again in the following month of October. Since then, however, it has enjoyed repose.

The effects of these eruptions were disastrous. The whole island was strown with volcanic ashes, which, where they did not smother the gra.s.s outright, gave it a poisonous taint. The cattle that ate of it were attacked by a murrain, of which great numbers died. The ice and snow, which had gathered about the mountain for a long period of time, were wholly melted by the heat. Ma.s.ses of pumice weighing nearly half a ton were thrown to a distance of between four and five miles.

[Ill.u.s.tration: Mount Hecla]

Mount Hecla is not the only volcano in Iceland. There are several others; and from one of them, named Skaptar Yokul, there was, in the year 1783, an eruption still more violent than that from Hecla above described. It began on the 8th of June, and raged with little abatement till the end of August, whence onward it continued, but with less violence, till the following year. The lava, in this case, poured from numerous openings; but these rivulets ultimately united themselves into two large currents, which flowed onwards to the sea. In their progress, these burning torrents filled up the beds of two considerable rivers. The greater of the two streams, after it had ceased to flow and had become a solid ma.s.s of rock, measured fifty miles in length, and between twelve and fifteen miles in breadth. Its average depth on the plains was about a hundred feet; but in the bed of the river, which it had filled, it was not less than six hundred feet. The snow and ice, which had previously covered the mountain, were not only melted, but the water that flowed from them was raised to the boiling point, and poured down with destructive effect on the plains. The dust and ashes thrown into the air darkened the sun; and they were then strown over the surface of the island, destroying all the pastures, so that many thousands of cattle, horses, and sheep perished. But worse than that, upwards of nine thousand persons lost their lives by this dreadful catastrophe.

About a month before this great eruption of Skaptar Yokul, a volcanic island was thrown up from the sea, at a distance of about seventy miles from Iceland. So great was the quant.i.ty of ashes and dross ejected from its crater, that it overspread the sea to a distance of a hundred and fifty miles, forming a crust which obstructed the progress of ships. Portions of this crust floated as far as the Shetland and Orkney islands. The King of Denmark named this fiery apparition "Nyoe," or "New Island," and doubtless prided himself not a little on this addition to his limited dominions.

But, alas, for human ambition! About a year after the date of its first appearance, Nyoe sank into the depths out of which it arose, and its position is now marked only by a moderate shoal.

It is not by their ejected lavas alone that the volcanoes of Iceland produce their destructive effects. Disastrous consequences have frequently resulted from the sudden melting of their snows and glaciers, on which the volcanic fires operate far more rapidly than does the heat of the sun. It is chiefly by the vast quant.i.ties of earth, sand, stones, and broken fragments of rock, which they hurry along with them in their wild career, that the waters, so suddenly freed, produce the greatest amount of damage. During an eruption of Katlugaia, one of the southern Icelandic volcanoes, in 1756, the ma.s.s of material thus carried down by the melted snows and glaciers was so great, that, advancing several leagues into the sea, it formed three parallel promontories, which rose above the sea-level, where there had formerly been a depth of forty fathoms of water.

Vast ravines were, at the same time, scooped out of the sides of the mountain by the erosion of the waters. Another eruption of this volcano in 1860 produced similar results.

Still more interesting than the volcanic mountains of Iceland are its Geysers, or intermittent springs of boiling water. The chief of these is the Great Geyser. A jet rises to a vast height, and is accompanied by much steam. Indeed, it is quite at the boiling-point.

The little mound, from the top of which the jet appears to rise, is composed of a substance named siliceous sinter, and is a deposit from the water of the fountain. At the top of this mound, which is between six and seven feet in height, there is an oval basin, measuring about fifty-six feet in one direction, and about forty-six in the other; its average depth is about three feet. In the centre of this basin is a round hole, about ten feet in diameter, out of which the water springs. This hole is the mouth of a circular well, between seventy and eighty feet in depth. It is down this well that the jet retires on its disappearance; and it drags along with it all the water out of the basin, leaving both basin and well quite empty, without even a puff of steam coming out of the hole. In this state of emptiness the basin and well remain for several hours. Suddenly the water begins to rise in the well, overflowing till it fills the basin. Loud explosions are heard from below, and the ground trembles. Then, with amazing violence, up springs a vast column of boiling water, surmounted by clouds of steam, which obscure the air. This first jet is followed by several others in rapid succession, to the number of sixteen or eighteen; the last jet being usually the greatest of all, and attaining a height of nearly a hundred feet. In some instances it has risen to a height of a hundred and fifty feet; and one particular jet was measured which rose to the amazing height of two hundred and twelve feet.

The action of the fountain seldom continues more than about five minutes at a time, and then a repose of several hours ensues. If left to itself, the periods of the fountain's activity, though not quite regular, generally recur at intervals of six or seven hours.

But they may be hastened by throwing big stones down the well. This not only hurries the eruption of the jet, but increases its energy, and the stones are thrown out with great force by the column of boiling water; the loudness of the explosions being also considerably augmented.

There are several other geysers in the island besides this big one.

Their jets are smaller, but to compensate this deficiency, they are more frequent in their ascent; so that travellers who are too impatient to await the eruptions of the Great Geyser, content themselves with visiting the little ones.