4 DISCUSSIONS IN CLIMATOLOGY. 



met with a favourable reception, but, as might have 

 been expected, it was soon abandoned. The researches 

 of Mr. Stockwell of America, and of Professor George 

 Darwin and others in this country, have put it beyond 

 doubt that no probable amount of geographical revolu- 

 tion could ever have altered the obliquity to any 

 sensible extent beyond its present narrow limits. It 

 has been demonstrated, for example, by Professor 

 George Darwin, that supposing the whole equatorial 

 regions up to lat. 45° N. and S. were sea, and the 

 water to the depth of 2000 feet were placed on the 

 Polar regions in the form of ice — and this is the most 

 favourable redistribution of weight possible for pro- 

 ducing a change of obliquity — it would not shift the 

 Arctic circle by so much as an inch ! 



Variations in the obliquity of the ecliptic having 

 been given up as hopeless, geologists and physicists 

 are now inquiring whether the true cause may not 

 be found in a change in the position of the earth's 

 axis of rotation. Fortunately this question has been 

 taken up by several able mathematicians, among 

 whom are Sir Wm. Thomson,* Professor Haughton,-f- 

 Professor George Darwin,! the Eev. J. F. Twisden,§ 

 and others ; and the result arrived at ought to convince 

 every geologist how hopeless it is to expect aid in this 

 direction. 



Professor George Darwin has demonstrated that in 

 order to displace the pole merely 1° 46' from its present 

 position, ^ of the entire surface of the globe would 

 require to be elevated to a height of 10,000 feet, with 

 a corresponding subsidence in another quadrant. 



* " British Association Report," 1876 (part 2), p. 11. 

 f " Proceedings of Royal Society," vol. xxvi., p. 51. 

 J " Transactions of Royal Society," vol. 167 (part 1). 

 § " Quart. Journ. Geol. Soc," February, 1878. 



