Professor A. Pleischl wrote in 1841 that he was told that ice formed on the Pleschiwetz and on the Steinberge in summer. Continuing, he says: "The author is therefore, as well as for other reasons, of the opinion, that the ice is not remaining winter ice, but a summer formation, and one formed by the cold of evaporation. * * * The basalt is, as a thick stone, a good conductor for the heat, and takes up therefore easily the sun's warmth, but parts with it easily to other neighboring bodies. In the hollows, between the basalt blocks, is found, as I already mentioned, rotting moss, which forms a spongy mass, which is wet through with water. The basalt heated by the sun's rays now causes a part of the water in the spongy mass to vaporize; for this evaporation the water needs heat, which it withdraws from the neighboring bodies and in part from water, and makes the water so cold, that it freezes into ice, as, under the bell of an air pump--Nature therefore makes here a physical experiment on the largest scale." Much stress appears to have been laid on the paper of Professor Pleischl by Professor Krauss and one or two others. The weak point in it is that Pleischl did not see the ice form in summer, but was only, as usual, told that it did so. There is nothing in the facts given to show that the places mentioned are different from any other taluses, where ice does not form as the result of heat. Mr. C. B. Hayden, in 1843, wrote about the Ice Mountain in Virginia, and held that the porous nature of the rocks makes them poor conductors of heat, and that the mountain is a huge sandstone refrigerator. Dr. S. Pearl Lathrop, in 1844, wrote of the Ice Bed at Wallingford, Vermont, as a great natural refrigerator. Sir Roderick Impey Murchison wrote in 1845 about the salt mine and freezing cave of Illetzkaya-Zatschita. He visited them during a hot August, and was assured that the cold within is greatest when the external air is hottest and driest; that the fall of rain and a moist atmosphere produce some diminution in the cold of the cave and that on the setting in of winter the ice disappears entirely. He accepted these statements evidently only in a half hearted way, submitting them to Sir John Herschel, who tried to explain them, in case they were true, of which Herschel was likewise doubtful. Murchison at first thought that the ice was due to the underlying bed of salt, but soon recognized that this explanation could not be correct. He also rejected Herschel's "heat and cold wave" theory. Shortly after this he came across Pictet's memoir, and on the strength of it concluded that the ice in Illetzkaya-Zatschita could not be the residue of a winter deposit, but must be due to descending currents of air; to the previously wet and damp roof affording a passage to water; and to the excessive dryness of the external air of these southern steppes contributing powerfully to the refrigerating effects of evaporation.