246 FEAGMENTS OF SCIENCE. 



for the bend, the adherent of the fracture theory must 

 assume the existence of some accident which turned 

 the crack at right angles to itself; and he surely will 

 permit the adherent of the erosion theory to make a 

 similar assumption. 



The influence of small accidents on the direction of 

 rivers is beautifully illustrated in glacier streams, 

 which are made to cut either straight or sinuous chan- 

 nels by causes apparently of the most trivial character. 

 In his interesting paper ' On the Lakes of Switzerland,' 

 M. Studer also refers to the bend of the Ehine at 

 Sargans in proof that the river must there follow a 

 pre-existing fissure. I made a special expedition to the 

 place in 1864; and though it was plain that M. Studer 

 had good grounds for the selection of this spot, I was 

 unable to arrive at his conclusion as to the necessity 

 of a fissure. 



Again, in the interesting volume recently published 

 by the Swiss Alpine Club, M. Desor informs us that 

 the Swiss naturalists who met last year at Samaden 

 visited the end of the Morteratsch glacier, and there 

 convinced themselves that a glacier had no tendency 

 whatever to imbed itself in the soil. I scarcely think 

 that the question of glacier erosion, as applied either to 

 lakes or valleys, is to be disposed of so easily. Let me 

 record here my experience of the Morteratsch glacier. 

 I took with me in 1864 a theodolite to Pontresina, 

 and while there had to congratulate myself on the aid 

 of my friend Mr. Hirst, who in 1857 did such good 

 service upon the Mer de Glace and its tributaries. We 

 set out three lines across the Morteratsch glacier, one 

 of which crossed the ice-stream near the well-known 

 hut of the painter Georgei, while the two others were 

 staked out, the one above the hut and the other below 

 it. Calling the highest line A, the line which crossed 



