40 Geology r , «£ illustrated by Chemistry and Physics. 



sent impressions from which it may be inferred that they 

 have been in a soft state. This view is also supported by 

 the fact that some fire-balls appeared spherical only at first, 

 and afterwards assumed a lengthened form. 



I believe that I have sufficiently proved * that the heating 

 of meteorites cannot, as Chladni assumed, be caused by the 

 air, compressed in consequence of the immense velocity with 

 which they move in space. Their heat cannot, therefore, be 

 derived from without, but must stand in some kind of casual 

 connection with their formation. The high temperature 

 which, from the occurrence of hot springs, volcanic pheno- 

 mena, and the polar flattenings, we infer our earth to have 

 possessed at the creation, and still to retain in its interior, 

 we now observe in the meteorites, which are probably frag- 

 ments of exploded cosmical bodies. \ A liquid state of cos- 

 mical bodies, caused by high temperatures, has then analo- 

 gies in the meteorites, which, moreover, correspond in their 

 composition with the formations upon our earth. 



The lava which was thrown out during historical periods, 

 and even before our eyes flows from volcanic craters, is very 

 similar to that which, in prehistorical ages, flowed from ex- 

 tinct or still active volcanoes. The lava from old streams 

 of Vesuvius, iEtna, and other volcanoes, the scorise, rapilli, 

 and the volcanic ashes of these still active volcanoes, are not 

 to be distinguished from the products of the extinct volcanoes 

 in the Eifel and the neighbourhood of the lake of Laach. 

 Upon Mosenberg, near Manderscheid, upon Falkenley, near 

 Bertrich, &c, the transition of scoriae into lava, and into 

 actual basalt, can be traced. Nothing was therefore easier 

 tli an to regard that basalt also which is found in other places, 

 and far from either active or extinct volcanoes, as a lava-like 

 production. The old lavas of Iceland, and the island Ischia 

 near Naples, so perfectly resemble the trachytes which rise 

 above the surface in steep cones, as in the Siebengebirge, 

 near Bonn, that there was in this case also no reason to 

 doubt a similarity of origin. 



* Populare Biiefe an sine gebildete Dame iiber die gesamten Gebiete der 

 Natur\vis;senschaften. Ertes Bandchen, 1848, p. 9G, et teq. 

 X Ibid, p. 102. et ■«><]., and p. 126, et seq. 



