CORROBORATIVE MEASUREMENTS.
279
Second Line.—Daily Motion.
No. of stake.
Inches.
No. of stake.
Inches.
West 1
moved
7*
11 moved 21
2
10}
12
22}
3
„
12}
13
21
4
it
14*
14
22}
5
>>
16
15
20}
6
„
16}
16
21}
7
17}
17
22}
8
19
18
25}
9
19}
19
10
15
21
20
25} East.
As regards the retardation of the side, we observe herethe same fact as that revealed by our first line—themotion gradually augments from the first stake to the last.The stake No. 20 stood upon the dirty portion of the ice,which was derived from the Talefre tributary of the Merde Glace, and far beyond the middle of the glacier.These measurements, therefore, corroborate that madelower down, as regards the non-coincidence of the pointof swiftest motion with the centre of the glacier.
But it will be observed that the measurements do notshow any retardation of the ice at the eastern extremity ofthe line of stakes—the motion goes on augmenting from thefirst stake to the last. The reason of this is, that in neitherof the cases recorded were we able to get the line quiteacross the glacier; the crevasses and broken ice-ridges,which intercepted the vision, compelled us to halt beforewe came sufficiently close to the eastern side to make itsretardation sensible. But on the 20th of July my friendHirst sought out an elevated station on the Chapeau, oreastern side of the valley, whence he could command aview from side to side over all the humps and inequalitiesof the ice, the fixed point at the opposite side, uponwhich the telescope was directed, being the corner of awindow of the Montanvert Hotel. Along this line were