the noise of a mountain that lay a good way off on our right. It discharged quantities of smoke, and made several explosions like heavy cannon at a distance; but what is singular, we could observe no appearance of fire.—This mountain was formed by an eruption in 1766, now upwards of four years ago; the fire of which is not yet extinguished, neither is the lava by any means cold. This lava spent its fury on a beautiful forest, which it laid waste to the extent of a good many miles. In many places it has run into gulleys of a great depth, which it has filled up to the height, we are told, of two hundred feet. It is in these places where it retains the greatest heat. On our road to-day, we scrambled up this lava, and went a considerable way over its surface, which appeared perfectly cold; but it is certain, that in many places it still emits volumes of smoke, particularly after rain; and the people say, what I can readily believe, that this will continue to be the case for some years, where the lava is thickest. A solid body of fire some hundreds of feet thick, and of so great an extent, must certainly retain its heat for many years. The surface, indeed, soon becomes black and hard, and incloses the liquid fire

within, in a kind of solid box, excluding all impressions from the external air or from the weather. Thus I have seen many months after eruptions of Mount Vesuvius, a bed of lava, though only of a few feet thick, has continued red-hot in the centre long after the surface was cold; and a stick thrust into its crevices instantly took fire, although there was no perceptible heat without.

Massa, a Sicilian author of credit, says he was at Catania eight years after the great eruption in 1669, and that he still found the lava in many places was not cold: but there is an easy method of calculating the time that bodies take to cool :-Sir Isaac Newton, I think, in his account of the comet of 1680, supposes the times to be as the squares of their diameters; and finding that a solid ball of metal of two inches, made red-hot, required upwards of an hour to become perfectly cold, made the calculation from that to a body of the diameter of the earth, and found it would require upwards of twenty thousand years. If this rule be just, you may easily compute the time that the lava will take to become thoroughly cold; and that vou may have time to do so, I shall here break off my letter, which I am

obliged to write in bed, in a very awkward and disagreeable posture; the cause of which shall

be explained to you in my next.

Adieu. Ever yours.

LETTER X.

Catania, May 29, at night.

AFTER getting a comfortable nap on our bed of leaves in the Spelonca del Capriole, we awoke about eleven o'clock; and melting down a sufficient quantity of snow, we boiled our tea kettle, and made a hearty meal to prepare us for the remaining part of our expedition.

We were nine in number; for we had our three servants, the Cyclops (our conductor), and two men to take care of our mules. The Cyclops now began to display his great knowledge of the mountain, and we followed him with implicit confidence. He conducted us over "Antres vast, and deserts wild," where

scarce human foot had ever trod. Sometimes through gloomy forests, which by day-light were delightful, but now, from the universal darkness, the rustling of the trees; the heavy dull bellowing of the mountain, the vast expanse of ocean stretched at an immense distance below us, inspired a kind of awful horror. Sometimes we found ourselves ascending great rocks of lava, where, if our mules should make but a false step, we might be thrown headlong over the precipice. However, by the assistance of the Cyclops, we overcame all these difficulties; and he managed matters so well, that in the space of two hours we found we had got above the regions of vegetation; and had left the forests of Etna far behind. These appeared now like a dark and gloomy gulf below us, that surrounded the mountain.

The prospect before us was of a very different nature; we beheld an expanse of snow and ice that alarmed us exceedingly, and almost staggered our resolution. In the centre of this, but still at a great distance, we descried the high summit of the mountain, rearing its tremendous head, and vomiting out torrents of smoke. It indeed appeared altogether inaccessible, from the vast extent of the fields of

Ac

snow and ice that surrounded it. Our diffidence was still increased by the sentiments of the Cyclops. He told us, it often happened, that the surface of the mountain being hot below melted the snow in particular spots, and formed pools of water, where it was impossible to foresee our danger; that it likewise happened that the surface of the water, as well as the snow, was sometimes covered with black ashes, that rendered it exceedingly deceitful; that however, if we thought proper, he would lead us on with as much caution as possible. cordingly, after holding a council of war, which you know people generally do when they are very much afraid, we detached our cavalry to the forest below, and prepared to climb the snows. The Cyclops, after taking a great draught of brandy, desired us to be of good cheer; that we had plenty of time, and might take as many rests as we pleased; that the snow could be little more than seven miles, and that we certainly should be able to pass it before sunrise. Accordingly, taking each of us a dram of liqueur, which soon removed every objection, we began our march.

The ascent for some time was not steep; and as the surface of the snow sunk a little,