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. 
Studer 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. 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 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, 8, 3, etc. in the tables. 
Morteratsch Glacier, Line A. 
No. of Stake. Hourly Motion, 
1 0.35 inch 
2 0.49 " 
8 0.58 " 
