EXPERIMENTS ON THE PLASTICITY OF ICE. 
175 
Table V. — Showing the variable azimuths (observed) of the transverse stations with 
the longitudinal direction Q q. 
Date. 
(1). 
(2). 
(3). 
(4). 
(5). 
Angle Ql Q q. 
August 12. 2 p.m. 
89 55 
89 55 
89 55 
O / 
O / 
89 55 
14. 1 P.M. 
90 61 
90 5 
90 5 
89 52 
17- Noon. 
90 26 
90 24 
90 23 
90 8 
89 471 
19. 5 P.M. 
90 47 
90 46 
90 44 
90 10 
89 52 
21. 6 p.m. 
90 56 
90 56 
90 53 
90 21 
90 3 
23. 1 p.m. 
91 91 
91 91 
91 41 
90 34 
90 14 
26. Noon. 
91 24 
91 23 
91 18 
90 45 
90 241 
89 281 
In the last column is the observed azimuth of the visual line joining the fixed point 
Ql with the moveable station Q, from the mark q in the glacier, on the first and last 
observation. This angle had therefore diminished by 26'|. Now from the known pro- 
gression of Q, and the known distance QQl, we computed at page 166 the rotation 
of the visual line, and found it to be 25' 54". This close correspondence is highly 
satisfactory, as showing that the relative positions of Q and q remained unchanged 
during the continuance of the experiment with reference to the imaginary transverse 
line by which they were adjusted. It is worthy of notice that the line Qq was exactly 
in the direction of the veined structure. 
Edinburgh, July 1845. 
2 A 
MDCCCXLVI. 
