Note 54 — Chapter VII · THE MINERAL CONSTITUENTS OF THE SOIL SOLUTION.[40]
Reading edition
A gel is a jelly-like substance, apparently continuous, which forms either by the settling from suspension in a liquid of very fine particles which then become aggregated; or, is formed by the evaporation of a liquid containing fine particles in suspension until the quantity of liquid remaining is just sufficient to serve as a cementation medium holding the suspended particles together in a semi-rigid mass. For an experimental demonstration of the formation of such a gel, see, The effect of water on rock powders, by Allerton S. Cushman, Bull. No. 92, Bureau of Chemistry, U. S. Dept. Agriculture, 1905.