. Principles of agricultural chemistry [microform] . orphic rocks were laid down by water or other agencies,but were afterwards subjected to such intense heat and pressureas to crystallize minerals in them. The physical and chemical character of the rock and of thesoil which may be derived from it, depends upon its chemicalcomposition, and the rapidity with which the igneous rock solidi-fies. If the molten mass cools ofif rapidly, so that it solidifies ina comparatively short time, minerals do not have time to crys-tallize, and a hard, homogenous, glassy mass is produced (glassyrock). If the m
. Principles of agricultural chemistry [microform] . orphic rocks were laid down by water or other agencies,but were afterwards subjected to such intense heat and pressureas to crystallize minerals in them. The physical and chemical character of the rock and of thesoil which may be derived from it, depends upon its chemicalcomposition, and the rapidity with which the igneous rock solidi-fies. If the molten mass cools ofif rapidly, so that it solidifies ina comparatively short time, minerals do not have time to crys-tallize, and a hard, homogenous, glassy mass is produced (glassyrock). If the molten material remains liquid for a long timeand cools slowly, the rock produced is a mixture of definiteminerals which can be easily distinguished (crystalline rock). 64 PRINCIPLES OF AGRICULTURAL CHEMISTRY Other conditions of cooling may give rise to a compact, stonymass, composed of minute crystals (stony rock) or to a rockcontaining large crystals of one or more kinds of mineral em-bedded in a stone or glass matrix (prophyry). These differences. Fig. 14.—Microscopic appearance of porphyry.
Size: 1610px × 1553px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookidprinciplesof, bookyear1913
