"The column was composed of a very special ice, perfectly dry, perfectly homogeneous, translucid and whose appearance could only be compared to that of the most beautiful porcelain. I am inclined to believe that we had under our eyes a special molecular state of congealed water. This state would be produced under the influence of a constant temperature of a certain degree (Note--perhaps not far from 4°--the actual temperature of the grotto) long prolonged. These causes can be realized more completely in glacières than anywheres else." The Reverend George Forrest Browne, published in 1865, _Ice Caves in France and Switzerland_, one of the most delightful books of travel ever written, on account of the scientific accuracy and the humor of the author. He visited La Genollière, Saint-Georges, Saint-Livres, Chaux-les-Passavant, Monthézy, Arc-sous-Çicon, the Schafloch, Haut-d'Aviernoz, which he calls Grand Anu, Chapuis, and Font-d'Urle. He says: "The view which Deluc adopted was one which I have myself independently formed. * * * The heavy cold air of winter sinks down into the glacières, and the lighter warm air of summer cannot on ordinary principles of gravitation dislodge it, so that heat is very slowly spread in the caves; and even when some amount of heat does reach the ice, the latter melts but slowly, for ice absorbs 60° C. of heat in melting; and thus, when ice is once formed, it becomes a material guarantee for the permanence of cold in the cave. For this explanation to hold good it is necessary that the level at which the ice is formed should be below the level of the entrance to the cave; otherwise the mere weight of the cold air would cause it to leave its prison as soon as the spring warmth arrived. In every single case that has come under my observation, this condition has been emphatically fulfilled. It is necessary, also, that the cave should be protected from direct radiation, as the gravitation of cold air has nothing to do with resistance to that powerful means of introducing heat. This condition, also, is fulfilled by nature in all the glacières I have visited, excepting that of S. Georges; and there art has replaced the protection formerly afforded by the thick trees which grew over the hole of entrance. The effect of the second hole in the roof of this glacière is to destroy all the ice which is within range of the sun. A third and very necessary condition is, that the wind should not be allowed access to the cave; for if it were, it would infallibly bring in heated air, in spite of the specific weight of the cold air stored within. It will be understood from my description of such glacières as that of the Grand Anu, of Monthézy, and the lower glacière of the Pré de S. Livres, how completely sheltered from all winds the entrances to those caves are. There can be no doubt, too, that the large surfaces which are available for evaporation have much to do with maintaining a