44 



H. F. Reid — Sbidles of Mvir Glacier 



was aljoiit at right angles to the line E-K. The change in the 

 positions of the flags could be well measured from these stations, 

 as the motion made a large angle with the lines joining the station 

 to the flags. The part of this motion at right angles to E-K was 

 taken as the actual motion. We have thus for the first period, 

 July 21 to 24, two independent measures, one from E and one 

 from K, which agree very well. The average is given in the table- 

 For the second period, observations of motion were made from K 

 only. The observations on the side flags from A" which extended 

 from July 21 to ilugust 8, are given in the column headed iii, 

 and in the last column are collected what I consider the most 

 reliable results. It will be seen that the motion, scarcely observ- 

 able at the sides, increases rapidly toward the center, where it 

 amounts to about 7 feet a day. A consideration of the size of the 

 instruments, their distance from the flags, and the size of the 

 flags themselves, shows that there is a possible, though scarcely 

 probable, error of some two feet in the determination of the 

 motion of the center flags, and not more than half so much in 

 that of the side flags.* 



Table showing Motion of the Flags in the Ice. 



I. Daily motion from July 21 to 24. 

 n. " ' " " August 4 to 8. 



III. " " " July 21 to August 8. 



IV. Best value of daily motion deduced from i, ii, and iii. 



* The flags were six feet long and three feet wide. The instruments 

 were those used in our survey and described later (see p. 53, foot-note). 

 I This determination was made from E for the period July 21 to Aug. 4. 



