THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FOURTH SERIES.] 



DECEMBER 1865, 



LVI. Professor Helmholtz on Ice and Glaciers, 



To the Editors of the Philosophical Magazine and Journal* 



Gentlemen, 



I HAVE been recently favoured by Professor Helmholtz with 

 a brochure entitled "Popular Scientific Lectures," from 

 the preface of which I learn with great satisfaction that other 

 discourses, of a cast similar to those here placed before the public, 

 may be expected to follow. The present pamphlet contains four 

 lectures, — -the first, " On the Relation of the Natural Sciences to 

 Science in general ;" the second, "On Goethe's labours in Natural 

 Science; " the third, "On the Physiological Origin of Musical 

 Harmony ;" and the fourth, " On Ice and Glaciers." The pam- 

 phlet is in German, and it is much to be desired that some com- 

 petent person should undertake its translation into English. 



I turned with natural interest to the last-mentioned discourse 

 to see how my notions and experiments on the formation and 

 motion of glaciers were regarded by so eminent a man. And as 

 it can hardly be doubted that the subject will also interest many 

 of the readers of the Philosophical Magazine, I will here endea- 

 vour to give a summary of the scientific portion of the lecture. 



Professor Helmholtz refers the cold of the upper regions of 

 the atmosphere to the causes generally assigned ; but he adds a 

 remark important at the present moment, when the origin of the 

 hot wind called Fohn in Switzerland is the subject of so much 

 discussion. This wind, as Helmholtz justly observes, may not 

 only be a cold wind upon the mountain summits, but a wet one. 

 It is deprived of its moisture upon the heights, and it is warmed 

 by its subsequent fall into the valleys. The heat and dryness of 



Phil. Mag. S. 4. Vol. 30. No. 205. Dec. 1865. 2 D 



