432 POPULAR SCIENCE MONTHLY. 



from them all by her characteristic fundamental idea of illimit- 

 able time. As all other sciences are terrestrial, but astronomy 

 alone celestial, so all other sciences belong to the present — the 

 " now " — but geology alone belongs to the illimitable past. The 

 fundamental idea of the one is infinite space, of the other infinite, 

 in sense of inconceivable, time. All other sciences, including as- 

 tronomy, are but a flash-light view of Nature. Geology alone is 

 a view of ISJ'ature in continuous movement, a life history — an evo- 

 lution of Nature. This mode of thought began to dawn only in 

 the closing years of the last and the opening years of the present 

 century. It seems to have been first clearly conceived by the mind 

 of Hutton in the last part of the eighteenth century. 



2. Inductive Method Applied. — When the true idea under- 

 lying geology was clearly conceived and geology thus distinctly 

 separated from other departments of science, geology may be said 

 to have been born. But it was still in helpless infancy, its growth 

 irregular, and even its continuous life uncertain, because a solid 

 basis of inductive method was not yet laid. That basis was laid 

 mainly by Hutton in 1795,* and still more clearly by Charles 

 Lyell in 1830, in the principle that the study of causes now in 

 oper-ation is the only true foundation of geology. 



Geological changes, of course, belong to the irrevocable past, 

 and are therefore hopelessly removed from direct observation. 

 Their causes and process must be reconstructed by the skillful use 

 of the scientific imagination. Until Lyell, more or less probable 

 hypotheses seemed all that was possible. AVhat a field was here 

 for the conflict of opposite extreme views! But Lyell showed that 

 " causes now in operation " are producing similar eifects under our 

 eyes, if we will only observe. From that moment geology became 

 a truly inductive science and its indefinite progress assured. 



These two events, then — viz., the conception of geology as a dis- 

 tinct science, and the introduction of a true scientific method — are 

 the greatest epochs in the history of geological science. Some dim 

 adumbrations of these appear before this century, especially the 

 former in the mind of Buffon, and the latter somewhat fully in the 

 mind of Hutton, but they were not generally accepted and had not 

 become working principles until the beginning and even some time 

 after the beginning of the nineteenth century. These must be 

 borne in mind in all we have further to say of the progress of geol- 

 ogy through the century. 



When the century opened, the war between the Neptunists and 

 the Plutonists, between the Wcrnerites and the Huttonites, was 

 still going on, but was approaching the usual result in such cases 



* niitton's Theory of the Earth. 



