THE PERIOD OF INCUBATION 69 



accomplish any great revolution. Soundness is to the 

 world of science what respectability is to the world of 

 business the sine qua non for successfully gaining even 

 a hearing from established personages. 



To read the book on Coral Reefs is indeed to take a 

 lesson of the deepest value in applied inductive canons. 

 Every fact is duly marshalled: every conclusion is 

 drawn by the truest and most legitimate process from 

 careful observation or crucial experiment. Bit by bit, 

 Darwin shows most admirably that, through gradual 

 submergence, fringing reefs are developed into barrier- 

 reefs, and these again into atolls or lagoon islands ; and 

 incidentally he throws a vivid light on the slow secular 

 movements upward or downward for ever taking place 

 in the world's crust. But the value of the work as a 

 geological record, great as it is, is as nothing compared 

 with its value as a training exercise in inductive logic. 

 Darwin was now learning by experience how to use his 

 own immense powers. 



Meanwhile, the environment too had been gradually 

 moving. In 1832, the year after young Darwin set out 

 upon his cruise, Lyell published the first edition of his 

 'Principles of Geology,' establishing once for all the 

 unifonnitarian concept of that branch of science. In 

 1836, the year when he returned, Rafinesque, in his 

 1 New Flora of North America,' had accepted within 

 certain cramping limits the idea that ' all species might 

 once have been varieties, and that many varieties are 

 gradually becoming species by assuming constant and 

 peculiar characters.' Haldeman in Boston, and Grant 

 at University College, London, were teaching from their 

 professorial chairs the self-same novel and revolutionary 



