ch. xin.] REVIEWS AND CRITICISMS, 18G0. 



243 



because Newton could not show what gravity itself is. As 

 it has chanced, I have used in letters this very same argu- 

 ment, little knowing that any one had really thus objected 

 to the law of gravity. Newton answers by saying that it is 

 philosophy to make out the movements of a clock, though 

 you do not know why the weight descends to the ground. 

 Leibnitz further objected that the law of gravity was op- 

 posed to Natural Keligion ! Is this not curious ? I really 

 think I shall use the facts for some introductory remarks 

 for my bigger book." 



0. D. to J. D. Hooker. Down, March 3rd [I860]. 



... I think you expect too much in regard to change 

 of opinion on the subject of Species. One large class of 

 men, more especially I suspect of naturalists, never will care 

 about any general question, of which old Gray, of the Brit- 

 ish Museum, may be taken as a type ; and secondly, nearly 

 all men past a moderate age, either in actual years or in 

 mind are, I am fully convinced, incapable of looking at 

 facts under a new point of view. Seriously, I am astonished 

 and rejoiced at the progress which the subject has made ; 



look at the enclosed memorandum. says my book will 



be forgotten in ten years, perhaps so ; but, with such a list, 

 I feel convinced the subject will not. 



[Here follows the memorandum referred to : ] 



Geologists. 



Lyell. 



Ramsay.* 



Jukes.f 



H. D. Rogers. $ 



Zoologists and 

 Paleontologists. 



Huxley. 



J. Lubbock. 



L. Jenyns 



(to large extent). 



Searles Wood* 



Physiologists. 



Carpenter. 



Sir H. Holland 



(to large extent). 



Botanists. 



Hooker. 



H. C. Watson. 



Asa Gray 



(to some extent). 



Dr. Boott 



(to large extent). 



Thwaites. || 



* Andrew Ramsay, late Director-General of the Geological Survey. 



+ Joseph Beete Jukes, M.A., F.R.S., born 1811, died 1869. He was edu- 

 cated at Cambridge, and from 1842 to 1846 he acted as naturalist to H.M.S. 

 Fly, on an exploring expedition in Australia and New Guinea. He was after- 

 wards appointed Director of the Geological Survey of Ireland. He was the 

 author of many papers, and of more than one good handbook of geology. 



% Professor ot Geology in the University of Glasgow. Born in the" United 

 States 1809, died 1866. 



# Searles Valentine Wood, died 1880. Chiefly known for his work on the 

 Mollusca of the Crag. 



| Dr. G. H. K. Thwaites, F.R.S., was born in 1811, or about that date, and 



