112 



Sierra Club Bulletin, 



ured. But measurements were made at right angles 

 to the base-line as selected, and a very slight correction 

 was made to obtain the true velocity. The slope of the 

 surface of the ice midway between holes 3 and 4 was 

 eleven degrees, and the distance from the line to the 

 snout was 2,950 feet. The results are collected in the 

 table, and are shown graphically in the figures. All 

 measurements were made about 10 a. m., and the daily 

 motions are for twenty-four hours. 



Motion of the Ice of Nisqually Glacier, July, 1906. 



HOLES 



DAILY MOTION IN INCHES 



DISTANCES OF 



July 18th 

 July 20th 



July 20th 

 to 



July 22d 



July 22d 

 to 



July 26th 



July 26th 

 • y 28th 



July 18th 

 to 



July 28th 



From east 

 edge 



From west 

 edge 



1 



11.3 



17.8 



10.1 



9.4 



11.8 



200 





2 



15.6 



17.3(?) 



14.9 



12.7 



15.1 



405 





3 



15.8 



21.9 



15.1 



13.1 



16.2 



558 





4 



15.0 



22.4 



14.2 



13.3 



15.8 



663 





5 



15.0 



21.1 



14.5 



12.8 



15.6 



810 





6 



15.0 



21.7 



13.6 



12.5 



15.2 



973 



510 



7 



15.0 



19.0 











460 



8 



12.4 



15.7 



10.2 



10.4 



11.8 





254 



9 



6.8 



7.9 



5.0 



5.7 



6.1 





75 



July 18-20 — Weather fair but cool. 



July 20-22 — Weather warm, dry wind. 



July 22-26 — Weather fair, changing to cloudy. 



July 26-28 — Weather cloudy, and raining. 



The more rapid movement of the center is evident. It 

 also appears that the eastern part of the section moved 

 more rapidly than the western part, and that the point 

 of maximum velocity is in the neighborhood of hole No. 3. 

 This is due to the fact that the glacier is not perfectly 

 straight, but is sweeping around a gentle curve with the 

 convex side to the east. A marked variation of velocity 

 occurs between the different periods, which seems to be 

 caused by changes in the rate of melting due to changes 



