[Footnote 97: M. de Thury calculated that the thickness of the roof at the lower part of the cave was about 60 feet of rock. He also noticed the peculiar structure of the ice, which afforded great surprise to his party. It was discovered by means of the coloured rays which were thrown into the different parts of the cave, when some one had casually placed a torch in a cavity in one of the columns.] * * * * * CHAPTER XV. OTHER ICE CAVES. _The Cave of Szelicze, or Szilitze, in Hungary_.[98] Matthew Bell, the historian of Hungary, sent an account of this cavern to England, in the middle of the last century, which was printed in the original Latin in the 'Philosophical Transactions' of 1739-40 (pp. 41, &c.). This account states that the cave is in the county of Thorn,[99] among the lowest spurs of the Carpathians. The entrance, which faces the north, and is exposed to the cold winds from the snowy part of the Carpathian range, is 18 fathoms high and 9 broad; and the cave spreads out laterally, and descends to a point 50 fathoms below the entrance, where it is 26 fathoms in breadth, and of irregular height. Beyond this no one had at that time penetrated, on account of the unsafe footing, although many distant echoes were returned by the farther recesses of the cave; indeed, to get even so far as this, much step-cutting was necessary. When the external frost of winter comes on, the account proceeds, the effect in the cave is the same as if fires had been lighted there: the ice melts, and swarms of flies and bats and hares take refuge in the interior from the severity of the winter. As soon as spring arrives, the warmth of winter disappears from the interior, water exudes from the roof and is converted into ice, while the more abundant supplies which pour down on to the sandy floor are speedily frozen there. In the Dog-days, the frost is so intense that a small icicle becomes in one day a huge mass of ice; but a cool day promptly brings a thaw, and the cave is looked upon as a barometer, not merely feeling, but also presaging, the changes of weather. The people of the neighbourhood, when employed in field-work, arrange their labour so that the mid-day meal may be taken near the cave, when they either ice the water they have brought with them, or drink the melted ice, which they consider very good for the stomach. It had been calculated that 600 weekly carts would not be sufficient to keep the cavern free from ice. The ground above the cave is peculiarly rich in grass.