332 



Nevertheless this theory is so directly opposed to our ordinary 

 experience of the nature of ice, as to leave a lingering douht of its 

 truth upon the mind. To remove this doubt it is urged, that the 

 true nature of ice is to he inferred from experiments on large masses, 

 and that such experiments place the viscosity of ice in the position 

 of a fact rather than in that of a theory. It has never been ima- 

 gined that the bendings and contortions, and other evidences of 

 apparent viscosity exhibited by a glacier, could be made manifest on 

 hand specimens of ice. In the present paper, however, this is shown 

 to be possible. Spheres of ice are described as being flattened into 

 cakes, and squeezed into transparent lenses. A straight prism of ice 

 six inches long, is described as having been passed through a series of 

 moulds augmenting in curvature, and finally coming out bent into a 

 semi-ring. A piece of ice is placed in a hemispherical cavity and is 

 pressed upon by a protuberance not large enough to fill the cavity, 

 and is thus squeezed into a cup. In short, every observation made 

 upon glaciers, and adduced by writers upon the subject in proof of 

 the plasticity of ice, is shown to be capable of perfect imitation with 

 hand specimens in the laboratory. 



These experiments, then, demonstrate a capacity on the part of 

 small masses of ice which has hitherto been denied to them by 

 writers upon this subject. They prove to all appearance that the 

 substance is even much more plastic than it has hitherto been sup- 

 posed to be ; but the real germ from which these results have sprung, 

 is to be found in a lecture given by Mr. Faraday at the Royal Institu- 

 tion in 1850, and reported in the 'Athenaeum' and 'Literary Gazette' 

 for that year. Mr. Faraday then showed, that when two pieces of 

 ice, at a temperature of 32 Fahr., are placed in contact, they freeze 

 together by the conversion of the film of moisture between them into 

 ice. The case of a snow-ball was referred to as a familiar illustration 

 of the principle : when the snow is below 32, and therefore dry, it 

 will not cohere, whereas when it is in a thawing condition, it can be 

 squeezed into a hard compact mass. During one of the hottest days 

 of last July, when the temperature was upwards of 100 Fahr. in the 

 sun, and more than 80 in the shade, a number of pieces of ice 

 placed loosely together in a window in the Strand, were observed by 

 one of us to be frozen together ; and he subsequently caused pieces 

 of ice to freeze together under hot water. Hence the thought arose, 



