THE UNIVERSE. DISCOVERIES IN THE CELESTIAL SPACES. 349 



pyrites. Even experiments made in sport by Lemery in the 

 year 1700 exerted a long-continued influence on volcanic 

 theories, although these might have been raised to more 

 general views by the imaginative Protogsea of Leibnitz 

 (1680). 



The Protogsea, which is sometimes more poetic than the 

 many metrical attempts of the same philosopher which have 

 recently been brought to light, ( 539 ) teaches the scorifi- 

 cation of the cavernous, glowing, and once self-luminous 

 crust of the earth; the gradual cooling of the heat- 

 radiating surface enveloped in vapours; the condensa- 

 tion, and precipitation into water, of the gradually cooled 

 atmosphere of vapour; the lowering of the sea by the 

 sinking of its waters into internal hollows in the earth ; 

 and finally the falling in of these caves or hollows causing 

 the inclination of the strata. The physical part of these 

 wild fancies offers some traits which, to the adherents of our 

 modern and every way more advanced geological science, 

 will not appear altogether deserving of rejection. Such are, 

 the transference of heat in the interior of the globe, and 

 the cooling by radiation from the surface ; the existence of 

 an atmosphere of vapour; the pressure exerted by these 

 vapours upon the strata during their consolidation ; and the 

 double origin of the masses as either fused and solidified or 

 precipitated from the waters. The typical character and 

 mineral differences of rocks, i. e. the associations of cer- 

 tain substances, chiefly crystalline, recurring in the most 

 distant regions of the earth, are as little spoken of in the 

 Protogsea as in Hooke's geognostical views. In the last 

 named writer, also, physical speculations on the operation 

 of subterranean forces in earthquakes, in the sudden eleva- 



