CHAPTER VI. 



EXAMINATION OF MR. ALFRED R. WALLACE'S MODIFICA- 

 TION OF THE PHYSICAL THEORY OF SECULAR CHANGES 

 OF CLIMATE. 



Effect of Winter Solstice in Aphelion. — The Star Storage of Cold. — 

 Highland and heavy Snowfall in Relation to the Glacial Epoch. 

 — The only Continental Ice on the Globe probably on Lowlands. 

 — Modification of Theory Examined. — General Statement of the 

 Theory. — Points of Agreement. 



There are few authors to whom I am more deeply 

 indebted than to Mr. Alfred R. Wallace for his very 

 clear and able exposition and defence from time to 

 time of the main points of the Physical Theory of 

 secular changes of climate. I have read the chapters 

 relating to this subject in his recent work (" Island 

 Life ") with a great amount of interest and pleasure ; 

 and I need hardly add that, in the main, I agree with 

 the views which he advocates. In these chapters, 

 however, there have been advanced some modifications 

 of the theory which, after a very careful reconsidera- 

 tion of the whole subject, I am wholly unable to 

 accept. As these modifications relate to points of the 

 greatest importance in the question of geological 

 climate, I shall now proceed to examine them at some 

 length. It appears to me, however, that what Mr. 

 Wallace regards as modifications are in some cases 

 really necessary parts of the theory. These may not, 

 it is true, have been in all cases expressed by me, but 



