LITERARY WORK, ETC. 215 



a captive balloon would afford a splendid view of the polar 

 regions and of all parts of the northern hemisphere. The 

 numerous advantages of this plan are explained in some detail, 

 and I have little doubt that it will be realized (perhaps on half 

 the scale) some time during the present century. The article 

 is contained in the second volume of my " Studies." 



I also wrote an article on " The Gorge of the Aar and its 

 Teachings," as serving to enforce my papers on the " Ice Age 

 and its Work ' three years before. But my most important 

 scientific essay this year was a paper I read to the Linnsean 

 Society on " The Problem of Utility." My purpose was to 

 enforce the view that all specific and generic characters must 

 be (or once have been) useful to their possessor, or, owing 

 to the complex laws of growth, be correlated with useful char- 

 acters. It was necessary to discuss this point, because 

 Mr. Romanes had unreservedly denied it, and Professor 

 Mivart, the Rev. Mr. Henslow, Mr. Bateson, and others, had 

 taken the same view. I endeavoured to show that the problem 

 is a fundamental one, that utility is the basic principle of 

 natural selection, and that without natural selection it has not 

 been shown how specific characters can arise. By specific is, 

 of course, meant characters which, either separately or in com- 

 bination, distinguish a species from all others, and which are 

 found in all, or in the great bulk, of the individuals composing 

 the species ; and I have shown that it is for want of clear think- 

 ing and accurate reasoning on the entire process of species- 

 formation that the idea of useless specific characters has arisen 

 (see "Studies," vol. i.)- 



I also reviewed Copes's " Primary Factors of Evolution " 

 and Dr. G. Archdall Reid's " Present Evolution of Man " in 

 Nature (April 16), and wrote a long letter in Nature (Janu- 

 ary 9) on " The Cause of the Ice Age," pointing out the 

 extreme complexity of the subject, and the fallacy of discuss- 

 ing the problem as if it were merely one of the amount of sun- 

 heat received in different latitudes under differing degrees of 

 eccentricity, as several eminent mathematicians had done. In 

 the same issue Sir Robert Ball pointed out the same fallacy; 

 and this affords a good illustration of the fact that specialists 



