266 APPENDIX, NO. II. 



equidistant wrinkles in [on] the sides of railway banks from mere 

 pressure above ; and more particularly in turnings of coarse malleable 

 iron, where, though the detruding force is constantly equal, still detru- 

 sion takes place at intervals, forming in the shaving so many wrinkles, 

 by which frontal resistance, too, it is thickened, and -consequently 

 shortened, similarly with the mechanism of the glacier." 



APPENDIX, No. II. 



ME. FAEADAY ON THE PEOPEETIES OF ICE. 



" . . . Mr. Faraday then invited attention to the extraordinary 

 property of ice in solidifying water which is in contact with it. Two 

 pieces of moist ice will consolidate into one. Hence the property of 

 damp snow to become compacted into a snow-ball an effect which 

 cannot be produced on dry, hard-frozen snow. Mr. Faraday suggested, 

 and illustrated by a diagram, that a film of water must possess the 

 property of freezing when placed between two sets of icy particles, 

 though it will not be affected by a single set of particles. Certain 

 solid substances, as flannel, will also freeze to an icy surface, though 

 other substances, as gold leaf, cannot be made to do so. In this 

 freezing action, latent heat becomes sensible heat, the contiguous 

 particles must therefore be raised in temperature while the freezing 

 water is between them. It follows from hence that, by virtue of the 

 solidifying power at points of contact, the same mass may be freezing 

 and thawing at the same moment, and even that the freezing process 

 in the inside may be a thawing process on the outside. Mr. Faraday 

 then referred to Mr. Thomson's memoirs on the effect of pressure on 

 the freezing point. Mr. Thomson has shewn that immense pressure 

 will prevent water from freezing. At 32 ice naturally occupies a 

 greater volume than that of the water which forms it ; and we may 

 conceive that, when ice is pressed, the tendency is to give it both the 

 water bulk and state. In conclusion, Mr. Faraday noticed briefly, 

 and chiefly by way of suggestion, the molecular condition of ice as 

 presenting many curious results, and called attention to the strangeness 

 of striae being formed in a body of such uniform composition as pure 

 water frozen into ice." From the Proceedings of the Royal Institu- 

 tion, reported in the Athenaeum, 15th June 1850, p. 641. 



