Forms of Ice

Abstract

A CURIOUS formation has lately occurred on the surface of a sheet of ice in a tub. Being under a tap, the ice became submerged below several inches of water. Fresh ice then formed as thin vertical plates upon, and at right angles to the submerged sheet. These plates meeting each other in all directions, produced a spongy mass, 3 or 4 inches thick. I do not know if it is a common production, but the special interest attached to it is that it would seem to suggest how “spongy” quartz has arisen, of which I have a specimen consisting of thin and nearly parallel plates; as well as the well-known form of thin crystalline plates in which calcite may occur. It is just this form of calcite which gives rise to “hacked” quartz, when silica has coagulated or crystallised over a mass of such thin crystals, and then these latter have been subsequently dissolved out.