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 strim being found in a body of such uniform composition as pure water frozen into ice.
On Ice of Irregular Fusibility[1].
My Dear Tyndall,
Have the following remarks, made in reference to the irregular fusibility of ice, to which you drew my attention,
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any interest to you, or by an occasional bearing on such cases, any value in themselves? Deal with them as you like.
Imagine a portion of the water of a lake about to freeze, the surface S being in contact with an atmosphere considerably below 32°, the previous action of which has been to lower the temperature of the whole mass of water, so the portion below the line M is at
- ↑ From Tyndall's paper "On some Physical Properties of Ice," Phil. Trans. 1858, p. 228.
