1876 LETTER TO PROFESSOR, MARSH 213 



He continues : 



That is what I mean by demonstrative evidence of 

 evolution. An inductive hypothesis is said to be demon- 

 strated when the facts are shown to be in entire accord- 

 ance with it. If that is not scientific proof, there are no 

 merely inductive conclusions which can be said to be 

 proved. And the doctrine of evolution, at the present 

 time, rests upon exactly as secure a foundation as the 

 Copernican theory of the motions of the heavenly bodies 

 did at the time of its promulgation. Its logical basis is 

 of precisely the same character the coincidence of the 

 observed facts with theoretical requirements. 



He left New York on September 23. " I had a 

 very pleasant trip in Yankee -land," he writes to 

 Professor Baynes, "and did not give utterance to a 

 good deal that I am reported to have said there." 

 He reached England in good time for the beginning 

 of his autumn lectures, and his ordinary busy life 

 absorbed him again. He did not fail to give his 

 London audiences the results of the recent discoveries 

 in American paleontology, and on December 4,' 

 delivered a lecture at the London Institution, " On 

 Recent Additions to the Knowledge of the Pedigree 

 of the Horse." In connection with this he writes 

 to Professor Marsh : 



4 MARLBOROTTGH PLACE, LONDON, N.W. 

 Dec. 27, 1876. 



MY DEAR MARSH I hope you do not think it remiss 

 of me that I have not written to you since my return, 

 but you will understand that I plunged into a coil of 

 work, and will forgive me. But I do not mean to let 



