74 Mr. H. H. Howorth on 



a ladder which De Saussure had lost on the Aiguille de la 

 Noire, in the year 1788. The distance it had travelled in 

 the 44 years was about 16,500 feet, giving an average of 

 375 feet per annum as the mean rate of progression 

 {Travels^ 87). 



On September 25th, 1842, the same traveller lost a 

 hammer, which fell into the great Moulin, opposite the ice 

 cascade, du Talefre. This hammer was recovered on 

 June 22nd, 1858, "not far below the Tacul" {Forbes' s 

 Life and Letters, 297). On the 29th of July, 1836, the 

 guide Michel Devouasson lost a knapsack on the Glacier du 

 Talefre, in a crevasse into which he had fallen. Fragments 

 of this knapsack were found on the Glacier du Lechaud on 

 the 24th of July, 1846, at a distance of 4,300 feet from 

 where it had been lost, which showed an annual pro- 

 gression of 430 feet (" Thirteenth Letter on Glaciers," Ed. 

 PhiL Journ., 1847). 



While facts like these must have made the motion of 

 glaciers well known to the Swiss peasants from early 

 times, it was apparently first published to the scientific 

 world by Simmler in his work " De Alpibus," published in 

 the middle of the sixteenth century. 



When it was established that glaciers actually move, men 

 began to try and find an adequate explanation of their 

 movement. The various theories which have been sug- 

 gested all appeal to one of two forces, namely, heat of 

 gravity. We will examine them in turn, and in doing so 

 shall find it convenient not to follow a chronological order, 

 but to first examine the various theories which more 

 or less exclude gravity as a factor in glacier motion and 

 which appeal to the action of heat in various ways. 



In his so-called " Itinera Helvetiae Alpinas Regiones," 

 1723 (pp. 287 — 8), J. J. Scheuchzer, referring to the motion 

 of glaciers, says: "The cause of this motion is not owing to 

 any miracle, as those ignorant of physics suppose, but is 



