OlSCOVElllES I?N THE CELESTIAL SPACES. 349 



tenlioii had been drawn to the regular succession of strata in 

 England, first felt the want of geognostic maps. Although 

 these phenomena, and their dependence on ancient inundations 

 (either single or repeated), riveted the attention of men, and, 

 mingling belief and knowledge together, gave origin in En- 

 gland to the so-called systems of Uay, Woodward, Burnet, and 

 Whiston ; yet, owing to the total want of mineralogical dis- 

 tinction between the constituents of compound minerals, all 

 that relates to crystalline and massive rocks of eruption re- 

 mained 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 unscien- 

 tific 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 ProtogcBa 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 

 cavernous, glowing, once self-luminous crust of the Earth, the 

 gradual cooling of the radiating surface enveloped in vapors, 

 the precipitation and condensation of the gradually-cooled, va- 

 porous 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 rejection 

 by the adherents of our modern geognosy, notwithstanding 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 atmosphere of vapor ; 

 the pressure exercised by these vapors on the Earth's strata 

 during their consolidation ; and the two-fold origin of the mass" 



studies, in V/hewell's History of the Inductive Sciences, 1837, vol. ili. , 

 p. 507-545. 



* Leibnizens, Geschichtliche Avfsdtze und Gedichte, edited by Pertz, 

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

 of the Protogcea of 1G91, and on its subsequent revisions, see Tellkampf 

 Juhrcsberichi der Burgerschnle zu Hannover, 1847, s. 1-32. 



