A Century of Science 13 



to be an Eocene world, and so on, until the aspect 

 of the world that we know to-day should noise 

 lessly steal upon us. 



When once the truth of Ly ell s conclusions be 

 gan to be distinctly realized, their influence upon 

 men s habits of thought and upon the drift of 

 philosophic speculation was profound. The con 

 ception of Evolution was irresistibly forced upon 

 men s attention. It was proved beyond question 

 that the world was not created in the form in which 

 we find it to-day, but has gone through many 

 phases, of which the later are very different from 

 the earlier ; and it was shown that, so far as the 

 inorganic world is concerned, the changes can be 

 much more satisfactorily explained by a reference 

 to the ceaseless, all-pervading activity of gentle, un 

 obtrusive causes such as we know than by an ap 

 peal to imaginary catastrophes such as we have no 

 means of verifying. It began to appear, also, that 

 the facts which form the subject-matter of different 

 departments of science are not detached and inde 

 pendent groups of facts, but that all are intimately 

 related one with another, and that all may be 

 brought under contribution in illustrating the his 

 tory of cosmic events. It was a sense of this inter 

 dependence of different departments that led Au- 

 guste Comte to write his &quot; Philosophic Positive,&quot; the 



