when relieved from the heat due to radiation.
At the time of this observation, there were still patches of snow lying on the mountain-side, exposed to the full power of direct radiation; and, therefore, there is not anything very surprising in the permanence of snow under such favourable circumstances as are developed in the cave.

Mr.Airy, a few summers ago, found the rooms of the Casa Inglese, on Mount Etna, half filled with snow, which had drifted in by an open door, and had been preserved from solar radiation by the thick roof.[121] Humboldt remarks, that the mean temperature of the region in which the Cueva del Hielo (ice-cave) occurs, is not below 3 deg.

C.( 37.4 deg.

F.), but so much snow and ice are stored up in the winter that the utmost efforts of the summer heat cannot melt it all.

He adds, that the existence of permanent snow in holes or caves must depend more upon the amount of winter snow, and the freedom from hot winds, than on the absolute elevation of the locality.
The natives of Teneriffe are men of faith.