Permanence of Continents 299 



geographical distribution must be one of the tests of their validity 1 . 

 What is of supreme interest is that it was also their starting-point. 

 He tells us: — "When I visited, during the voyage of H.M.S. Beagle, 

 the Galapagos Archipelago,... I fancied myself brought near to the 

 very act of creation. I often asked myself how these many peculiar 

 animals and plants had been produced : the simplest answer seemed 

 to be that the inhabitants of the several islands had descended from 

 each other, undergoing modification in the course of their descent 2 ." 

 We need not be surprised then, that in writing in 1845 to Sir Joseph 

 Hooker, he speaks of "that grand subject, that almost keystone of the 

 laws of creation, Geographical Distribution 3 ." 



Yet De Candolle was, as Bentham saw, unconsciously feeling his 

 way, like Lyell, towards evolution, without being able to grasp it. 

 They both strove to explain phenomena by means of agencies which 

 they saw actually at work. If De Candolle gave up the ultimate 

 problem as insoluble : — " La creation ou premiere formation des etres 

 organises eehappe, par sa nature et par son anciennete, a nos moyens 

 d'observation*," he steadily endeavoured to minimise its scope. At 

 least half of his great work is devoted to the researches by which he 

 extricated himself from a belief in species having had a multiple 

 origin, the view which had been held by successive naturalists from 

 Gmelin to Agassiz. To account for the obvious fact that species 

 constantly occupy dissevered areas, De Candolle made a minute study 

 of their means of transport. This was found to dispose of the vast 

 majority of cases, and the remainder he accounted for by geographical 

 change 5 . 



But Darwin strenuously objected to invoking geographical change 

 as a solution of every difficulty. He had apparently long satisfied 

 himself as to the "permanence of continents and great oceans." 

 Dana, he tells us, "was, I believe, the first man who maintained" 

 this 6 , but he had himself probably arrived at it independently. 

 Modern physical research tends to confirm it. The earth's centre 

 of gravity, as pointed out by Pratt from the existence of the Pacific 

 Ocean, does not coincide with its centre of figure, and it has been 

 conjectured that the Pacific Ocean dates its origin from the separa- 

 tion of the moon from the earth. 



The conjecture appears to be unnecessary. Love shows that "the 

 force that keeps the Pacific Ocean on one side of the earth is gravity, 

 directed more towards the centre of gravity than the centre of the 



1 Life and Letters, n. p. 78. 



s The Variation of Animals and Plants (2nd edit.), 1890, i. pp. 9, 10. 



:i Life and Letters, i. p. 336. 4 Loc. cit. p. 1106. B Loc. cit. p. 1116. 



6 Life and Letters, in. p. 247. Dana says : — " The continents and oceans had their 

 general outline or form defined in earliest time," Manual of Geology, revised edition. 

 Philadelphia, 1869, p. 732. I have no access to an earlier edition. 



