GEOLOGY. 131 



that earth from which all water has been withdrawn. 

 Two periods of precipitation exist therefore in geogeny, 

 one that of the identical or fundamental earths, and one 

 of the internally subdivided calcareous earths. 



585. The silicious, argillaceous, and talcose earths 

 must occupy, from their having been first precipitated, 

 the middle of the planet. The w r ater being earthy every- 

 where, had everywhere the capacity to become earth ; 

 but different earths originated, where the light was 

 different in the fluid mass of earth. In pure light, 



or that upon the surface, the Earthy dualized itself into ! 

 calcareous earth ; in situations, where the light exercised 

 less influence, the Earthy became talcose, still deeper \^ 

 argillaceous earth ; lastly, at such a depth where the light 

 could scarcely reach, the Earthy became a pure Earthy 

 or silicious earth. 



586. Precipitation, both upon a large and small scale, 

 is a process of crystallization ; the integral parts of the 

 planet originate, like the nucleus and the perfected crystal, 

 through central action and polar action. The integral 

 forms of the planet impart the crystalline granule or its 

 joints. 



587. The integral forms of the three fundamental 

 earths crystallized with and through each other into one 

 mass, or, in other words, the nucleus of the earth consists 

 of a crystalline mass of the three fundamental earths. 

 The solid nucleus of the earth consists of crystals upon a 

 small scale of silex, clay, and talc. 



588. As, however, no pole is produced of perfect 

 purity in nature, so are the integral forms not perfectly 

 pure fundamental earths, but other and later factors enter 

 also into their composition, e. g. calcareous earth, with 

 even ores and salts. The silicious earth is crystallized as ; 

 quartz, the argillaceous as feldspar, the talc as mica. 



589. The mixture of the three crystallized fundamental 

 earths, which composes the nucleus of the earth, and 

 upon which the polarized masses of soil have been sup- 

 ported, is therefore a definite species of rock, which has all 

 the properties of Granite, although that which has been 

 extruded from the earth may have been altered by heat. 



