SCIENTIFIC WRITINGS. 401 



had risen in the interior of the large dark crater, 

 explosion-like eruptions occurred with great regularity 

 at intervals of several seconds. More exact observation 

 showed that each explosion was followed by an ab- 

 sorption of air, so powerful, that the opening often 

 sucked in at the same time even ejected scoriae or 

 stones, which were again precipitated in its vicinity. 

 Inflammable gases, evolved continually from the earth's 

 interior, must have become mixed in the upper vent 

 of the crater with atmospheric air, which had been 

 absorbed by the rarefaction of the air caused by the 

 preceding explosion, and thereupon exploded, to pro- 

 duce anew a rarefied space. This observation led me 

 to a consideration of the process of the formation of 

 the earth and its present condition from a physico- 

 mechanical standpoint, the results of which differed 

 considerably from the prevailing opinions. 



Two diametrically opposed views have hitherto 

 been advanced in geology, that of the pure geologists 

 and that of the mathematicians. The former mostly 

 adhere to the old view, already to be called historical, 

 that the earth was once in a molten state, whilst air 

 and water formed the likewise still glowing atmosphere, 

 that then with progressive refrigeration and after forma- 

 tion of a solid crust the seas were disengaged, and with 

 the help of frequent partial elevations and depressions 

 of the crust deposited the vast sedimentary strata, which 

 now cover almost the whole surface. These elevations 

 and depressions were said to be produced by internal 

 volcanic forces, which still to this day give evidence of 



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