156 Beport of the Researches of M. Agassiz. 



and E 265. Bat it must be noticed, that it was not possible 

 to discover in a satisfactory manner, the original position of 

 block E, and it was .moreover apparent, that this block had 

 rolled over to the bottom of the moraine, and had thus been 

 displaced to an extent that could not be accurately apprecia- 

 ted. Eegarding this result then as uncertain, we may deduce 

 from the others that the glacier advances less rapidly towards 

 its extremity than in the upper regions. According to these 

 data, the most rapid movement must be placed in the neigh- 

 bourhood of M. Hugi's hut, from which locality it decreases 

 both in ascending and descending. This result, like that of 

 the stakes, is directly contrary to the belief of most observers ; 

 but we shall see ere long, that it could scarcely be otherwise, 

 provided the movement is really effected in consequence of in- 

 filtration, for, as the ice of the terminal regions is more com- 

 pact than that of the upper ones, it is thereby less suscep- 

 tible of imbibing so completely. It is true that Professor 

 Forbes obtained on the Mer de Glace of Chamouni, results 

 which were diametrically opposed to ours ; and he adduced this 

 circumstance as one of his reasons for rejecting the theory of 

 infiltration. According to him the lower part of the glacier 

 advances more rapidly than the upper part, in the ratio of 5 to 

 3. But it should be observed, that his data rest only upon 

 observations made only during a few weeks in the height of 

 summer, while M. Agassiz' s have reference to the movement 

 of the whole year. And it can in no degree excite surprise, 

 if it be found, that, at the beginning of summer, the terminal 

 portion during a certain period, really moves more rapidly than 

 the upper portions, which at that time are still more or less 

 covered with snow. 



With the view of completing these measurements, M. Agas- 

 siz has come to the determination of getting a topographical 

 map prepared, and applied to M. Wild, engineer, who joined 

 us on the glacier of the Aar in the beginning of July 1842, 

 that he might there commence a trigonometrical survey 

 of the glacier. The map, which is to be in the proportion of 

 one ten-thousandth part, being destined to form a part of M. 

 Agassiz* new work, I shall not anticipate the details it is 

 intended to illustrate. I shall limit myself to the remark, 



