

upon Glacier -motion. 



Number 



August 22. 



August 24. 



of stake. 



Distances. 



Distances. 



0. 



ft. in. 



ft. in. 



1. . 



, . 27 



26 10 



2. . 



, . 33 



33 



3. , 



, . 30 



30 



4. • 



. 30 



30 4 



5. , , 



. 30 



30 



6. , , 



, 30 



30 0-5 



417 



180 180 2*5 



We were surprised to find that during the two days' interval 

 the space between and 1 had been shortened by two inches. 

 It is not probable that this was due to an error of observation, 

 as the difference was found to be distributed over most of the 

 subdivisions. The elongation of the space between 3 and 4 was 

 "due to the widening of a crevasse which crossed the line obliquely 

 in that part. 



The following are the absolute and relative motions of the 

 stakes during the two days' interval :— 



Number Absolute motion. Relative motion. 



of stake 







inches. 



inch. 



0. 



. . . 





1. 







, 3-00 



0-50 



2. 







4-00 



1-00 



3. 







5-25 



1-25 



4. 







350 



-1-75 



5. 







4-50 



1-00 



6. 







5-00 



0-50 



These figures show an increase of differential motion in pro- 

 ceeding from the edge of the glacier to a point about thirty yards 

 distant, and a subsequent decrease in proceeding towards the 

 centre ; with a relative regression of the ice in the neighbour- 

 hood of stake 4, as indicated by the negative sign. The 

 greatest differential motion is between stakes 3 and 4. It 

 amounts to no more than *875 inch in twenty-four hours over a 

 distance of 360 inches, or about ¥ Jq of an inch in twenty-four 

 hours in points one inch apart. Between 5 and 6 it is only y^Vo 

 of an inch for the same time and space. 



The displacements of the stakes intermediate between and I, 

 and 5 and 6, were also determined. Each intermediate stake 

 was found to share in the differential motion. 



The measurements were confined to a breadth of 60 yards in 

 a part of the glacier where the distance from side to centre was 

 not less than 600 yards, and consequently only exhibit the de- 

 portment of the side ice. It was important to supplement them 

 by examining a glacier in the central portion of the stream; and, I 



Phil, Mag, S. 4. Vol. 42. No. 282. Dec. 1871. 2 E 



