374 On Ice of Irregular Fusibility. [1858. 



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 shown 

 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 found in a body of such uniform composition as 

 pure water frozen into ice. 



On Ice of Irregular Fusibility** 

 MY DEAR TYNDALL, 



HAVE the following remarks, made in reference to the 

 irregular fusibility of ice, to which you drew my attention, 



any interest to you, or by an occasional 32 



bearing on such cases, any value in 33 



themselves? Deal with them as you 34 



like. 35 



Imagine a portion of the water of a 3G 



lake about to freeze, the surface S being 37 



in contact with an atmosphere con- 38 



siderably below 32, the previous action 39 



of which has been to lower the tempe- 40 



rature of the whole mass of water, so 40 



that the portion below the line M is at 40 



* From Tyndall's paper " On some Physical Properties of Ice," Phil. Trans. 

 1858, p. 228. 



M 



