188 FRAGMENTS OF SCIENCE. 



("Proc. Roy. Soc." vol. xii. p. 678). To account, then, 

 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 assump- 

 tion. 



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 channels by 

 causes apparently of the most trivial character. In his 

 interesting paper "On the Lakes of Switzerland," M. 

 Stnder also refers to the bend of the Rhine 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. Stnder 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 them- 

 selves 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 congrat- 

 ulate 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 the 

 glacier at the hut B, and the lowest line C, the following 

 are the mean hourly motions of the three lines, deduced 

 from observations which extended over several days. On 

 each line eleven. stakes were fixed, which are designated by 

 the figures 1, 2,3, etc. in the tables. 



Morteratsch Glacier, Line A. 



No. of Stake. Hourly Motion. 



1 0.35 inch 



2 0.49 " 



3 ..0.53 " 



