84 PHYSIOGNOMY OF PLANTS. 



into a steppe or grassy plain, because without water no 

 organic development is possible. , 



( 10 ) p. 14. " The mas$ of the earth in solidifying and 

 parting with its heat" 



If, according to the hypothesis of the Neptunists, now long 

 since obsolete, the so-called primitive rocks, were precipitated 

 from a fluid, the transition of the crust of the earth from a 

 fluid to a solid state must have been accompanied by ail 

 enormous disengagement of heat, which would in turn have 

 caused fresh evaporation and fresh precipitations. The later 

 these precipitations, the more rapid, tumultuous, and uncrys- 

 talline they would have been. Such a sudden disengagement 

 of heat might cause local augmentations of temperature 

 independent of the height of the pole or the latitude of the 

 place, and independent of the position of the earth's axis ; 

 and the temperatures thus caused would influence the dis- 

 tribution of plants. The same sudden disengagement of 

 heat might also occasion a species of porosity, of which there 

 seem to be indications in many enigmatical geological phe- 

 nomena in sedimentary rocks. I have developed these con- 

 jectures in detail in a small memoir " iiber ursprungliche 

 Porositat." (See my work entitled Versuche iiber die che- 

 mische Zersetzung des Luftkreises, 1799, S. 177; and 

 Moll's Jahrbiicher der Berg- und Hiittenkunde, 1797, S. 

 234.) According to the newer views which I now entertain, 

 the shattered and fissured earth, with her molten interior, 

 may long have maintained a high temperature on her oxy- 

 dised surface, independently of position in respect to the sun 



