336 EVOLUTION [CHAP. V 



Letter 248 than myself of carrying on our work ; and of these you rank 

 as the first. 



With cordial good wishes for your success in all your 

 work and for your happiness. 



Letter 249 To E. Ray Lankester. 



Down, April I5th [1872]. 



Very many thanks for your kind consideration. The 

 correspondence was in the AtJienceum. I got some mathema- 

 tician to make the calculation, and he blundered and caused 

 me much shame. I send scrap of proofs from last edition of 

 the Origin, with the calculation corrected. What grand work 



o * o 



you did at Naples ! I can clearly see that you will some day 

 become our first star in Natural History. 



Here follows the extract from the Origin, sixth edition, p. 51 : "The 

 elephant is reckoned the slowest breeder of all known animals, and I 

 have taken some pains to estimate its probable minimum rate of natural 

 increase. It will be safest to assume that it begins breeding when thirty 

 years old, and goes on breeding till ninety years old, bringing forth six 

 young in the interval, and surviving till one hundred years old ; if this be 

 so, after a period of from 740 to 750 years, there would be nearly nineteen 

 million elephants alive, descended from the first pair." In the fifth 

 edition, p. 75, the passage runs : " If this be so, at the end of the fifth 

 century, there would be alive fifteen million elephants, descended from 

 the first pair" (see Athenccum, June 5, July 3, 17, 24, 1869). 



Letter 250 To C. Lyell. 



Down, May roth [1872]. 



I received yesterday morning your present of that work 

 to which I, for one, as well as so many others, owe a debt 

 of gratitude never to be forgotten. I have read with the 

 greatest interest all the special additions ; and I wish with all 

 my heart that I had the strength and time to read again every 

 word of the whole book. 1 I do not agree with all your criti- 

 cisms on Natural Selection, nor do I suppose that you would 

 expect me to do so. We must be content to differ on several 

 points. I differ most about your difficulty (p. 496) 2 on a 



1 Principles of Geology, Ed. xn., 1875. 



2 In Chapter XLIII. Lyell treats of " Man considered with reference 

 to his Origin and Geographical Distribution." He criticises the view that 

 Natural Selection is capable of bringing about any amount of change 

 provided a series of minute transitional steps can be pointed out. " But 



