In explanation of these phenomena, Bell threw out the following suggestions, which need no comment. The earth being of itself cold and damp, the external heat of the atmosphere, by partially penetrating into the ground, drives in this native cold to the inner parts of the earth, and makes the cold there more dense. On the other hand, when the external air is cold, it draws forth towards the surface the heat there may be in the inner part of the earth, and thus makes caverns warm. In support and illustration of this view, he states that in the hotter parts of Hungary, when the people wish to cool their wine, they dig a hole 2 feet deep, and place in it the flagon of wine, and, after filling up the hole again, light a blazing fire upon the surface, which cools the wine as if the flagon had been laid in ice. He also suggests that possibly the cold winds from the Carpathians bring with them imperceptible particles of snow, which reach the water of the cave, and convert it into ice. Further, the rocks of the Carpathians abound in salts, nitre, alum, &c., which may, perhaps, mingle with such snowy particles, and produce the ordinary effect of the snow and salt in the artificial production of ice. Townson[100] visited this cave half a century later, and concluded that Bell was in error with regard to the supposed winter thaw and summer frost, although he himself received information at Kaschau which corroborated the earlier account. He describes the approach to the village of Szilitze as leading by a by-road through a pleasant country of woods and hills, with much pasture-land, the cave lying a mile beyond the village, and displaying an entrance 100 feet broad, and 20 or 30 feet high, turned towards the north. The descent of the floor of the cave is rapid, and was covered with thin ice, at the time of his visit, for the last third of the way: from the roof at the farther end, where the cave is not so high as at the entrance, a congeries of icicles was seen to hang; and in a corner on the right, completely sheltered from the rays of the sun, there was a large mass of the same material. It was a fine forenoon in July, and all was in a state of thaw, the icicles dropping water, and the floor of ice covered with a thin layer of water; while the thermometer in all parts of the cave stood at zero of Réaumur's scale. The rock is compact unstratified limestone, in which so many of the famous caverns of the world are found. _The Cave of Yeermalik, in Koondooz_[101] In the year 1840, Captain Burslem, of the 13th Light Infantry, made an expedition from Cabul to the North-west, accompanied by Lieutenant Sturt of the Bengal Engineers, who was afterwards killed in the terrible pass where Lady Sale, whose daughter he had married, was shot through the arm.