Alfred Russel Wallace 



To Prop. Mbldola 



Parkstone, Dorset. July 8, 1897. 



My dear Meldola, — ... I am now reading a wonder- 

 fully interesting book — O. Fisher's " Physics of the Earth's 

 Crust." It is really a grand book, and, though full of un- 

 intelligible mathematics, is so clearly explained and so full 

 of good reasoning on all the aspects of this most difficult 

 question that it is a pleasure to read it. It was especially 

 a pleasure to me because I had just been writing an article 

 on the Permanence of the Oceanic Basins, at the request of 

 the Editor of Natural Science, who told me I was not ortho- 

 dox on the point. But I find that Fisher supports the same 

 view with very great force, and it strikes me that if weight 

 of argument and number of capable supporters create ortho- 

 doxy in science, it is the other side who are not orthodox. 

 I have some fresh arguments, and I was delighted to be able 

 to quote Fisher. It seems almost demonstrated now that 

 Sir W. Thomson was wrong, and that the earth has a molten 

 interior and a very thin crust, and in no other way can the 

 phenomena of geology be explained. . . . — Yours very truly, 



Alfred R. Wallace. 



To Sir Oliver Lodge 



Parkstone, Dorset. March 8, 1898. 



My dear Sir, — My own opinion has long been — and I have 

 many times given reasons for it — that there is always an 

 ample amount of variation in all directions to allow any 

 useful modification to be produced, very rapidly, as com- 

 pared with the rate of those secular changes (climate and 

 geography) which necessitate adaptation ; hence no guidance 

 of variation in certain lines is necessary. For proof of this 

 I would ask you to look at the diagrams in Chapter III. of 



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