EXPERIMENTS ON THE PLASTICITY OF ICE. 
167 
Table II. 
Table of the Apparent and True Motions of the Stations relatively to Station Q. 
Date. 
Interval. 
Motion 
of Q. 
Apparent relative motions. 
True relative motions. 
30 feet. 
60 feet. 
90 feet. 
120 feet. 
180 feet. 
30 feet. 
60 feet. 
90 feet. 
120 feet. 
1 80 feet. 
days. 
inch. 
inch. 
inch. 
inch. 
inch. 
inch. 
inch. 
inch. 
inch. 
inch. 
inch. 
August 9. 
6 P.M 
00 
00 
0-0 
00 
0-0 
0-0 
0-0 
o-o 
10. 
3£ P.M 
0-90 
14-0 
0-8 
1-9 
23 
0-65 
1-6 
1-8 
12. 
2 P.M 
1-94 
25-6 
1-7 
31 
3-7 
1-4 
2-5 
2-8 
14. 
1 P.M 
1-96 
29-0 
1-5 
2-8 
4-3 
0-0 
1-15 
21 
3-25 
0-0 
17. 
Noon 
2-96 
44 
2-1 
40 
6-0 
7-1 
o-o 
1-6 
2-95 
4-45 
5-0 
0-0 
19. 
5 P.M 
2-21 
33-2 
1-7 
2-7 
4-4 
6-2 
8-5 
1-4 
21 
3-25 
4-75 
6-15 
23. 
1 P.M 
3-83 
48 
2-5 
5-8 
7-7 
10-3 
15-0 
1-95 
4-7 
605 
8-15 
11-75 
26. 
Noon 
2-96 
34-6 
2-1 
4-6 
6-5 
8-0 
11-0 
1-7 
3-6 
5-3 
6-4 
8-6 
Motion from 9th to 26th... 
16-76 
228-4* 
9-85 
19-55 
26-9 
Motion from 17th to 26th... 
11-96 
159-8 
6-65 
13-35 
1905 
24-3 
Motion from 19th to 26th... 
9-00 
115-8 
5-05 
104 
14-6 
193 
26-5 
The results in the preceding Table have been divided into three periods, corre- 
sponding to the unequal times of observation of the last two and the first three sta- 
tions. The first line of addition includes the motion at thirty, sixty, and ninety feet 
for nearly seventeen days ; the second sum contains the comparative results for four 
stations throughout twelve days, and the last line contains the entire relative motions 
of five stations for nine days. These results may be further analysed, as in the fol- 
lowing Table, which exhibits the mean daily motion in inches corresponding to each 
point for these distinct periods, and also the ratio of the relative motion of each point 
to the actual motion of the glacier at Q, or the zero point, during the same interval. 
Table III. 
Interval 
in days. 
Actual 
motion of 
Q, or zero 
point. 
(10 
30 feet. 
(2.) 
60 feet. 
(3.) 
90 feet. 
(4.) 
120 feet. 
(5.) 
180 feet. 
Mean daily 
relative 
motion. 
Ratio to 
actual 
motion. 
Daily 
relative 
motion . 
Ratio to 
actual 
motion. 
Daily 
relative 
motion. 
Ratio to 
actual 
motion. 
Daily 
1 relative 
| motion. 
Ratio to 
actual 
motion. 
Daily 
relative 
motion. 
Ratio to 
actual 
motion. 
inch. 
inch. 
inch. 
inch. 
inch. 
inch. 
16-76 
228-4 
0-59 
0043 
1-17 
0-086 
1-60 
0-118 
11-96 
159-8 
0-56 
0042 
1-12 
0-084 
1-59 
0119 
2-03 
0152 
9-00 
115-8 
0-56 
0-044 
1-16 
0-090 
1-62 
0126 
216 
0-167 
2-94 
0-229 
This Table shows, first, in a striking point of view, the regularity of action of the 
law by which the variable motion of the different transversal points in the glacier is 
governed, since the movement in the different intervals bears so near a proportion, that 
when estimated in terms of the actual motion of the glacier at the place, the relative 
motion of the parts scarcely differs by unity in the second place of decimals, and is 
generally much under it. Taking into account the inevitable errors of observation 
and the extraordinarily unfavourable circumstances of the weather, it is in the very 
highest degree improbable that this law of continuity of the partial motions can beac- 
* The true sum ought to be about four inches greater. The difference arises from the impossibility of esti- 
mating the correct velocities for the fractional intervals. 
MDCCCXLVI. 
Z 
