734 CCSMOS. 



ancient inundations (either single or repeated), rivetted the 

 attention of men, and, mingling belief and knowledge together, 

 gave origin in England to the so-called systems of Ray, 

 Woodward, Burnet, and Whiston; yet owing to the total 

 want of mineralogical distinction between the constituents of 

 compound minerals, all that relates to crystalline and massive 

 rocks of eruption remained unexplored. Notwithstanding 

 the opinions held with respect to a central heat in the earth, 

 earthquakes, hot springs, and volcanic eruptions, were not 

 regarded as the consequence of the reaction of the planet 

 against its external crust, but were attributed to trifling local 

 causes, as, for instance, the spontaneous combustion of beds 

 of iron pyrites. The unscientific experiments of Lemery 

 (1700) unhappily exercised a long continued influence on 

 volcanic theories, although the latter might certainly have 

 been raised to more general views by the richly imaginative 

 Protogaa of Leibnitz (1680). 



The Protogcea occasionally even more imaginative than the 

 many metrical attempts of the same author, which have lately 

 been made known,* teaches " the scorification of the cavern- 

 ous, glowing, once self-luminous crust of the earth, the gra- 

 dual cooling of the radiating surface enveloped in vapours, 

 the precipitation and condensation of the gradually cooled 

 vaporous atmosphere into water, the sinking of the level of 

 the sea by the penetration of water into the internal cavities 

 of the earth, and finally the breaking in of these caves, which 

 occasions the fall, or horizontal inclination, of these strata." 

 The physical portion of this wild and fanciful view presents 

 some features which will not appear to merit entire rejec- 

 tion by the adherents of our modern geognosy, notwith- 

 standing its more perfect development in all its branches. 

 Among these better traits we must reckon the movement and 

 heat in the interior of the globe, and the cooling occasioned 

 by radiation from the surface; the existence of an atmo- 

 sphere of vapour ; the pressure exercised by these vapours 

 on the earth's strata during their consolidation ; and the 



* Leibnizens geschichtliche Aufsdtze und Gediclite, edited by Pertz, 

 1847, in the Gesammelte Wcrke: Geschichte, bd. iv. On the first 

 sketch of the Protogcea of 1691, and on its subsequent revisions, 

 see Tellkampf, Jahresbericht der Burgersclmle zu Hannover, 1847, 

 6. 1-32. 



