CHAPTER IV. 



THE LAW OF EVOLUTION. 



Laplace has somewhere reminded us that, while gratefully 

 rendering to Newton the homage due to him for his trans- 

 cendent achievements, we must not forget how singularly 

 fortunate he was in this — that there was but one law of 

 gravitation to be discovered. The implication that, if Newton 

 had not lived, Laplace might himself have been the happy 

 discoverer, is perhaps a legitimate one, though it does not 

 now especially concern us. But the implied assertion that 

 Nature had no more hidden treasures comparable in worth 

 and beauty to that with which she rewarded the patient 

 sagacity of the great astronomer, is one which recent events 

 have most signally refuted. We now know that other laws 

 remained behind — as yet others still remain — unrevealed ; 

 laws of nature equalling the law of gravitation in universality, 

 and moreover quite as coy of detection. For while it may 

 be admitted that the demonstrations in the " Principia " 

 required the highest power of quantitative reasoning yet 

 manifested by the human mind; and while the difficulties 

 and discouragements amid which Newton approached his 

 task, destitute as he was alike of modern methods of mea- 

 surement and of the resources of modern analysis, impress 

 upon us still more forcibly the wonderful character of the 



