174 Report of the Researches of M. Agassiz^ 



arrested, after having cleared a way for itself, in a few mo- 

 ments, to the extent of half a league, with a noise and de- 

 struction altogether astonishing." (De Saussure, Voyages 

 dans les Alpes, tome i., p. 384, § 538.) 



M. Kuhn observed a still more striking movement, occa- 

 sioned by the formation of a crevice in the glacier of Grin- 

 delwald ; and hence he concluded that this was the cause of 

 the advancing motion. It could not then be denied that 

 glaciers possessed a movement, which was continued from day 

 to day ; a circumstance which was not afterwards sufficiently 

 attended to. M. Venetz still maintains the theory of glid-' 

 ing in his celebrated memoir upon the variations of tem- 

 perature in the Alps ; where he narrated that there were 

 glaciers which made sudden bounds forwards to the extent 

 of ten feet. Here, however, it should be noted, that this 

 phenomenon was not observed by M. Venetz himself, and 

 that the statement rested upon the simple assertion of the 

 native mountaineers. Add to this, that since attention has 

 latterly more steadily been directed to the subject, no ex- 

 ample of this kind of advance has been recorded. Nothing 

 then remains, but that we should return to the slower move- 

 ment. 



M. Toussaint de Charpentier, brother of the celebrated geo- 

 logist of Bex, and M. Biselx, prior of the convent of St Ber- 

 nard, revived the theory of dilatation ; but from this period 

 the question became in a wonderful degree complicated. 

 It now became necessary to explain what the influences were 

 by which the movement was effected, and whether it was 

 continuous, or occurred only at certain times ? and, under 

 the last alternative, what were the periods of progression 1 

 also, if the movement was uniform, or, on the contrary, was 

 liable to times of retardation and acceleration ? These ques- 

 tions, it was evident, could not be determined in a manner at 

 all satisfactory, unless by accurate measurements. When we 

 consider the paucity of the measurements which we possess 

 even now, we may well be astonished that any theory what- 

 ever could be based upon such meagre data. The admea- 

 surements commenced by M. Hugi upon the glacier of the 



