18 DISCUSSIONS IN CLIMATOLOGY. 



and I think it will be admitted that the views which 

 I have advocated on these points are now being 

 generally, if not almost universally accepted. 



But it is in reference to the influence of aqueous 

 vapour, fogs, and clouds on the production and preser- 

 vation of snow that the greatest diversity of opinion 

 has prevailed. The object of the present chapter is to 

 examine at some length the principal objections which 

 have been advanced in regard to this part of the 

 inquiry. I shall also take the present opportunity of 

 discussing more fully some points on which I have 

 been sometimes misunderstood, and which appear to 

 have been treated rather too briefly on former occa- 

 sions. 



In the " American Journal of Science" for April, 

 1876, Professor Newcomb has done me the honour to 

 review at some length my work, ' Climate and Time ; ' 

 and as his article is mainly devoted to a criticism of 

 my reasoning in regard to those very points to which 

 I refer, I shall begin with an examination of his 

 objections. One reason for entering at some length 

 into an examination of Professor Newcomb's objections 

 is the fact that they embrace to a large extent those 

 which have been urged by reviewers in Great Britain. 

 Some of his objections, however, as will be seen, are 

 based upon a misapprehension of my reasoning. More 

 recently, in an article in that Journal for January, 

 1884, and in the "Phil. Mag." for February, 1884, he 

 has advanced other objections. 



Professor Newcomb states that he has a want of 

 confidence in anything short of a purely mathematical 

 investigation of the subject. Of course, I fully concur 

 with him as to the desirability of a " purely mathe- 

 matical investigation of the subject." Such an investi- 

 gation, however, is, I think, impossible at present. 



