they set up some turfs on the lee-side of the hole, to catch and force it down. These turfs being removed to the windy side, or laid over the mouth of the hole, the miners below presently want breath, and faint; and if sweet smelling flowers chance to be place there, they immediately lose their fragrancy, and stink like carrion." An air so very putrifying can never be very commodious for respiration.

Indeed, if we examine the complexion of most miners, we shall be very well able to form a judgment of the unwholesomeness of the place where they are confined. Their pale and sallow looks show how much the air is damaged by passing through those deep and winding ways, that are rendered humid by damps, or warmed with noxious exhalations. But although every mine is unwholesome, all are not equally so. Coal-mines are generally less noxious than those of tin; tin than those of copper; but of all, none are so dreadfully destructive as those of quicksilver. At the mines near the village of Idra, nothing can adequately describe the deplorable infirmities of such as fill the hospital there; emaciated and crippled, every limb contracted or convulsed, and some in a manner transpiring quicksilver at every pore. There was one man, says Dr. Pope, who was not in the mines above half a year, and yet whose body was so impregnated with this mineral, that, putting a piece of brass money in his mouth, or rubbing it between his fingers, it immediately became as white as if it had been washed over with quicksilver. In this manner all the workmen are killed sooner or later; first becoming paralytic, and then dying consumptive: and all this they sustain for the trifling reward of sevenpence a-day.

But these metallic mines are not so noxious from their own vapours as from those of the substances with which the ores are usually united, such as arsenic, cinnabar, bitumen, or vitriol. From the fumes of these, variously combined, and kept inclosed, are produced those various damps that put on so many dreadful forms, and are usually so fatal. Sometimes these noxious vapours are perceived by the delightful fragrance of their smell, somewhat resembling the pea-blossom in bloom, from whence one kind of damp has its name. The miners are not deceived, however, by its flattering appearances; but as they thus have timely notice of its coming, they avoid it while it continues, which is generally during the whole summer season. Another shows its approach by the burning of the candles, which seem to collect their flame into a globe of light, and thus gradually lessen, till they are quite extinguished. From this, also, the miners frequently escape; however, such as have the misfortune to be caught in it either swoon away and are suffocated, or slowly recover in excessive agonies. Here, also, is a third, called the fulminating damp, much more dangerous than either of the former, as it strikes down all before it like a flash of gunpowder, without giving any warning of its approach. But there is still another, more deadly than all the rest, which is found in those places where the vapour has been long confined, and has been by some accident set free. The air rushing out from thence always goes upon deadly errands; and scarce any escape to describe the symptoms of its operations.

Some colliers in Scotland, working near an old mine that had been long closed up, happened inadvertently to open a hole into it from the pit where they were then employed. By great good fortune they at that time perceived their error, and instantly fled for their lives. The next day, however, they were resolved to renew their work in the same pit, and eight of them ventured down, without any great apprehensions; but they had scarce got to the bottom of the stairs that led to the pit, but, coming within the vapour, they all instantly dropped down dead, as if they had been shot. Amongst these unfortunate poor men, there was one whose wife was informed he was stifled in the mine; and, as he hap

pened to be next the entrance, she so far ventured down as to see where he lay. As she approached the place, the sight of her husband inspired her with a desire to rescue him, if possible, from that dreadful situation; though a little reflection might have shown her it was then too late. But nothing could deter her; she ventured forward, and had scarce touched him with her hand, when the damp prevailed, and the misguided but faithful creature fell dead by his side.

Thus, the vapours found beneath the surface of the earth are very various in their effects upon the constitution; and they are not less in their appearances. There are many kinds that seemingly are no way prejudicial to health, but in which the workmen breathe freely; and yet in these, if a lighted candle be introduced, they immediately take fire, and the whole cavern at once becomes one furnace of flame. In mines, therefore, subject to damps of this kind, they are obliged to have recourse to a very peculiar contrivance to supply sufficient light for their operations. This is by a great wheel, the circumference of which is beset with flints, which, striking against steels placed for that purpose at the extremity, a stream of fire is produced which affords light enough, and yet does not set fire to the mineral vapour.

Of this kind are the vapours of the mines about Bristol; on the contrary, in other mines, a single spark struck out from flint and steel would set the whole shaft in a flame. In such, therefore, every precaution is used to avoid a collision-the workmen making use only of wooden instruments in digging, and being cautious before they enter the mine to take out even the nails from their shoes. Whence this strange difference should arisethat the vapours of some mines catch fire with a spark, and others only with a flame-is a question that we must be content to leave in obscurity, till we know more of the nature both of mineral vapour and of fire. This only we may observe, that gunpowder will readily fire with a spark, but not with the flame of a candle; on the other hand, spirits of wine will ignite with the flame of a candle, but not with a spark. But even here the cause of this difference as yet remains a secret.

As, from this account of mines, it appears that the internal parts of the globe are filled with vapours of various kinds, it is not surprising that they should at different times reach the surface, and there put on various appearances. In fact, much of the salubrity and much of the unwholesomeness of climates and soils is to be ascribed to these vapours, which make their way from the bowels of the earth upwards, and refresh or taint the air with their exhalations Salt mines, being naturally cold, send forth a degree of coldness to the external air to comfort and refresh it; on the contrary, metallic mines are known not only to warm it with their exhalations, but often to destroy all kinds of vegetation by their volatile corrosive fumes. In some mines dense vapours are plainly perceived issuing from their mouths, and sensibly warn to the touch. In some places, neither snow nor ice will continue on the ground that covers a mine; and over others the fields are found destitute of verdure. The inhabitants, also, are rendered dreadfully sensible of these subterraneous exhalations-being affected with such a variety of evils, proceeding entirely from this cause, that books have been professedly written upon this class of disorders.

Nor are these vapours which thus escape to the surface of the earth entirely unconfined, for they are frequently, in a manner, circumscribed to a spot; the grotto Del Cane, near Naples, is an instance of this, the noxious effects of which have made that cavern so very famous. This grotto, which has so much engaged the attention of travellers, lies within four miles of Naples, and is situated near a large lake of clear and wholesome water. Nothing can exceed the beauty of the landscape which this lake affords, being surrounded with hills covered with forests of the most beautiful verdure, and

the whole bearing a kind of amphitheatrical appearance. However, this region, beautiful as it appears, is almost entirely uninhabited-the few peasants that necessity compels to reside there looking quite consumptive and ghastly, from the poisonous exhalations that rise from the earth. The famous grotto lies on the side of a hill, near which place a peasant resides, who keeps a number of dogs for the purpose of showing the experiment to the curious. These poor animals always seem perfectly sensible of the approach of a stranger, and endeavour to get out of the way; however, their attempts being perceived, they are taken and brought to the grotto-the noxious effects of which they have so frequently experienced. Upon entering this place, which is a little cave, or hole rather, dug into the hill, about eight feet high, and twelve feet long, the observer can see no visible marks of its pestilential vapour; only to about a foot from the bottom, the wall seems to be tinged with a colour resembling that which is given by stagnant waters. When the dog, this poor philosophical martyr, as some have called him, is held above this mark, he does not seem to feel the smallest inconvenience; but when his head is thrust down lower, he struggles to get free for a little; but in the space of four or five minutes he seems to lose all sensation, and is taken out seemingly without life. Being plunged into the neighbouring lake he quickly recovers, and is permitted to run home, seemingly without the smallest injury.

This vapour, which thus for a time suffocates, is of the humid kind, as it extinguishes a torch and sullies a looking-glass; but there are other vapours perfectly inflammable, and that only require the approach of a candle to set them blazing. Of this kind was the burning well at Brosely, which is now stopped up; the vapour of which, when a candle was brought within about a foot of the surface of the water, caught flame like spirits of wine, and continued blazing for several hours after. Of this kind, also, are the perpetual fires in the kingdom of Persia. In that province where the worhippers of fire hold their chief mysteries, the whole surface of the earth, for some extent, seems impregnated with inflammable vapours. A reed stuck into the ground continues to burn like a flambeau; a hole made beneath the surface of the earth instantly becomes a furnace, answering all the purposes of a culinary fire. There they make lime by merely burying the stones in the earth, and watch with veneration the appearances of a flame that has not not been extinguished for time immemorial. How different are men in various climates! This deluded people worship the vapours as a deity, which, in other parts of the world, are considered as one of the greatest evils.

CHAP. IX.

OF VOLCANOES AND EARTHQUAKES.

Mines and caverns, as we have said, reach but a very little way under the surface of the earth, and we have hitherto had no opportunities of exploring farther. Without all doubt, the wonders that are still unknown surpass those that have been represented, as there are depths of thousands of miles which are hidden from our inquiry. The only tidings we have from those unfathomable regions are by means of volcanoes-those burning mountains that seem to discharge their materials from the lowest abysses of the earth. A volcano may be considered as a cannon of immense size, the mouth of which is often near two miles in circumference. From this dreadful aperture are discharged torrents of flame and sulphur, and rivers of melted metal. Whole clouds of smoke and ashes, with rocks of enormous size, are discharged to many miles distance; so that the force

of the most powerful artillery is out as a breeze agitating a feather in comparison. In the deluge of fire and melted matter which runs down the sides of the mountain, whole cities are sometimes swallowed up and consumed. Those rivers of liquid fire are sometimes two hundred feet deep, and, when they harden, frequently form considerable hills. Nor is the danger of these confined to the eruption only; the force of the internal fire, struggling for vent, frequently produces earthquakes through the whole region where the volcano is situated. So dreadful have been these appearances, that men's terrors have added new horrors to the scene, and they have regarded as prodigies what we know to be the result of natural causes. Some philosophers have considered them as vents communicating with the fires of the centre, and the ignorant as the mouths of hell itself. Astonishment produces fear, and fear superstition; the inha bitants of Iceland believe the bellowings of Hecla are nothing else but the cries of the damned, and that its eruptions are contrived to increase their tortures.

But if we regard this astonishing scene of terror with a more tranquil and inquisitive eye, we shall find that these conflagrations are produced by very obvious and natural causes. We have already been apprised of the various mineral substances in the bottom of the earth, and their aptness to burst out into flames. Marcasites and pyrites in particular, by being humified with water or air, contract this heat, and often endeavour to expand with irresistible explosion. These, therefore, being lodged in the depths of the earth or the bosom of mountains, and being either washed by the accidental influx of waters below or fanned by air, insinuating itself through perpendicular fissures from above, take fire a first by only heaving in earthquakes, but at length by bursting through every obstacle, and making their dreadful discharge in a volcano.

These volcanoes are found in all parts of the earth. In Europe there are three that are very remarkable— Etna in Sicily, Vesuvius in Italy, and Hecla in Iceland. Etna has been a volcano for ages immemorial, Its eruptions are very violent, and its discharge has been known to cover the earth sixty-eight feet deep. In the year 1537, an eruption of this mountain produced an earthquake through the whole island for twelve days. overturned many houses, and at last formed a new aperture, which overwhelmed all within five leagues round. The cinders thrown up were driven even into Italy, and its burnings were seen at Malta at the distance of sixty leagues. 'There is nothing more awful," says Kircher, "than the eruptions of this mountain, nor nothing more dangerous than attempting to examine its appearances, even long after the eruption has ceased. As we attempt to clamber up its steepy sides, every step we take upward the feet sink back half way. Upon arriving near the summit, ashes and snow, with an illassorted conjunction, present nothing but objects of desolation. Nor is this the worst, for, as all places are covered over, many caverns are entirely hidden from the sight, into which if the inquirer happens to fall, he sinks to the bottom, and meets inevitable destruction. Upon coming to the edge of the great crater, nothing can sufficiently represent the tremendous magnificence of the scene. A gulf two miles over, and so deep that no bottom can be seen; on the sides pyramidical rocks starting out between apertures that emit smoke and flame; all this accompanied with a sound that never ceases, louder than thunder, strikes the bold with horror, and the religious with veneration for Him that has power to control its burnings."

In the descriptions of Vesuvius or Hecla, we shall find scarce anything but a repetition of the same terrible objects, but rather lessened, as these mountains are not so large as the former. The crater of Vesuvius is but a mile across, according to the same author; whereas that of Etna is two miles. On this particular, however, we

sulphureous steam having surprised me, and almost taken away my breath. During our return, which was about three o'clock in the morning, the roaring of the mountain was heard all the way, and we observed it throwing up huge spouts of fire and burning stones, which, falling, resembled the stars in a rocket. Sometimes I observed two or three distinct columns of flame, and sometimes one only, which was large enough to fill the whole crater. These burning columns and fiery stones seemed to be shot a thousand feet perpendicular above the summit of the volcano; and in this manner the mountain was raging for six or eight days after. On the 18th of the same month the whole appearance ended, and the mountain remained perfectly quiet, without any visible smoke or flame."-[The annexed engraving represents an eruption which took place Aug. 2 and 3, 1847.] The matter which is found to roll down from the mouth of all volcanoes in general resembles the dross that is thrown from a smith's forge. But it is different, perhaps, in various parts of the globe; for, as we have already said, there is not a quarter of the world that has not its volcanoes. In Asia, particularly in the islands of the Indian Ocean, there are many One of the most famous is that of Albouras, near Mount Taurus, the summit of which is continually on fire, and covers the whole adjacent country with ashes. In the island of Ternate there is a volcano which, some travellers assert, burns most furiously in the times of the equinoxes, because of the winds which then contribute to increase the flames. In the Molucca Islands there are many burning mountains; they are also seen in Japan, and the islands adjacent; and in java and Sumatra, as well as in other of the Philippine Islands. In Africa there is a cavern, near Fez, which continually sends forth either smoke or flames. In the Cape de Verde Islands, one of them, called the Island del Fuego, continually burns; and the Portuguese, who frequently attempted a settlement there, have as often been obliged to desist. The Peak of Teneriffe is, as everybody knows, a volcano that seldom desists from eruptions. But of all parts of the earth America is the place where those dreadful irregularities of Nature are the most conspicuous. Vesuvius, and Etna itself, are but mere fire works in comparison to the burning mountains of the Andes, which, as they are the highest mountains in the world, so also are they the most formidable for their eruptions. The mountain of Arequipa, in Peru, is one of the most celebrated; Tarassa and Malahallo are very considerable; but that of Cotopaxi, in the province of Quito, exceeds anything we have hitherto read or heard of. The mountain of Cotopaxi, as described by Ulloa, is more than three miles perpendicular from the sea; and it became a volcano at the time of the Spaniards' first arrival in that country. A new eruption happened in the year 1743, having been some days preceded by a continual roaring in its bowels. The sound of one of these mount ins is not, like that of the volcanoes in Europe, confined to a province, but is heard at 150 miles distance. "An aperture was made," says Ulloa, "in the summit of this immense mountain, and three more, about equal heights, near the middle of its declivity, which was at that time buried under prodigious masses of snow. The ignited substances ejected on that occasion, mixed with an immense quantity of ice and snow melting amidst the flames, were carried down with such astonishing rapidity, that in an instant the valley from Callo to Latacunga was overflowed; and besides its ravages in bearing down the houses of the Indians and other poor inhabitants, great numbers of people lost their lives. The river of Latacunga was the channel of this terrible flood, till, being too small for receiving such a prodigious current, it overflowed the adjacent country, like a vast lake near the town, and carried away all the buildings within its reach. The inhabitants retired into a spot of higher ground behind the town,

of which those parts which stood within the limits of the current were totally destroyed. The dread of still greater devastations did not subside for three days; during which the volcano ejected cinders, while torrents of melted ice and snow poured down its sides. The erup tion lasted several days, and was accompanied with ter rible roarings of the wind, rushing through the volcano, still louder than the former rumblings in its bowels. At last all was quiet-neither fire nor smoke to be seen nor noise to be heard; till, in the ensuing year, the flames again appeared with recruited violence, forcing their passage through several other parts of the mountain, so that in clear nights the flames, being reflected by the transparent ice, formed an awfully magnificent illumination."

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Such is the appearance and the effect of those fires which proceed from the more inward recesses of the earth; for that they generally come from deeper regions than man has hitherto explored I cannot avoid thinking, contrary to the opinion of Mr. Buffon, who supposes them rooted but a very little way below the bed of the mountain. We can never suppose," says this great naturalist," that these substances are ejected from any great distance below, if we only consider the great force already required to fling them up to such vast heights above the mouth of the mountain; if we consider the substances thrown up, which we shall find upon inspection to be the same with those of the mountain below; if we take into our consideration that air is always neces sary to keep up the flame; but, most of all, if we attend to one particular circumstance—which is, that if these substances were exploded from a vast depth below, the same force required to shoot them up so high would act against the sides of the volcano, and tear the whole mountain in pieces." To all this specious reasoning particular answers might easily be given, as that the length of the funnel increases the force of the explosion; that the sides of the funnel are actually often burst with the great violence of the flame; that air may be sup posed at depths at least as far as the perpendicular tis sures descend. But the best answer is a well-known fact-namely, that the quantity of matter discharged from Etna alone is supposed, upon a moderate compu tion, to exceed twenty times the original bulk of the mountain. The greatest part of Sicily seems covered with its eruptions. The inhabitants of Catania have found, at the distance of several miles, streets and houses sixty feet deep, overwhelmed by the lava or matter it has discharged. But what is still more remarkable, the walls of these very houses have been built of materials evidently thrown up by the mountain. The inference from all this is very obvious-that the matter thus exploded cannot belong to the mountain itself, otherwise it would have been quickly consumed; it cannot be derived from moderate depths, since its amazing quantity evinces that all the places near the bottom must have long since been exhausted; nor can it have an extensive and, if I may so call it, a superficial spread, for theu the country would be quickly undermined; it must, therefore, be supplied from the deeper regions of the earth-those undiscovered tracts where the Deity performs his wonders in solitude, satisfied with self-appro bation!

CHAP. X.

OF EARTHQUAKES.

Having given the theory of volcanoes, we have, in some measure, given also that of earthquakes. They both seem to proceed from the same cause, only with this difference, that the fury of the volcano is spent in the eruption, that of an earthquake spreads wider, and acts more fatally by being confined. The volcano only