THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FOURTH SERIES.] 



JULY 1870. 



I. On the Cause of the Descent of Glaciers. 

 By John Ball, F.R.S. $c* 



AFTER a long period of rest, the controversy respecting the 

 motion of glaciers which occupied so much of the atten- 

 tion of scientific men during the period between 1842 and 1858 

 has been lately reopened. The Rev. Henry Moseley, who had 

 already in 1855 proposed a theory which failed to obtain the 

 adhesion of men conversant with the facts of glacier-motion, 

 made a communication to the Royal Society in January 1869, 

 wherein he sought to establish the insufficiency of the theory 

 generally accepted by men of science. The mathematical inves- 

 tigation on which he grounded the results given in that paper 

 was communicated to this Journal in May 1869. 



Having cleared the way by removing from his path the esta- 

 blished theory, Canon Moseley proceeded to prepare for the ad- 

 mission of his own views by two papers which also appeared in 

 this Journal. In August last he published an elaborate mathe- 

 matical investigation of the problem of the " descent of a solid 

 body on an inclined plane when subjected to alternations of tem- 

 perature;" and this was followed in January last by a paper 

 upon " The Mechanical Properties of Ice/' embodying the results 

 of observations and experiments made by himself and others 

 upon the dilatation, tenacity, and shearing-force of ice. At a 

 Meeting of the Bristol Naturalists' Society in December last, 

 Canon Moseley gave a tolerably full exposition of his own theory, 

 and has lately developed the same views, nearly in the same 



* Communicated by the Author. 

 Phil. Mag. S. 4. Vol. 40. No. 264. July 1870. B 



