6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 76 



due to the fact that on the former side the ice is sweeping through 

 a broad arc, which normally has the effect of deflecting the zone of 

 most rapid motion away from the middle. When, as here, the curve 

 is associated with a reversed curve further upstream, the deflection, 

 following the analogy of running water, naturally would be more 

 pronounced. And so, in fact, we find it here, the zone of maximum 

 velocity being thrown far over towards the southeasterly margin. 

 Actually it occurs about half-way between the center and the side 

 instead of at the center. 



The weather during the period of our stay was generally warm 

 and pleasant, although windy and smoky, the smoke at times settling 

 down in a dense pall almost obscuring the sun and hindering both 

 mountaineering and photography. 



2. INSTRUMENTAL TRIANGULATION FOR LOCATION AND 



MEASUREMENT OF A LINE OF STONES AND FOR 



EFFECTING CONNECTION WITH THE 



GOVERNMENT MAP 



Conditions for the laying off of a base-line on the surface of the ice 

 were not very favorable in the neighborhood of the line of stones, 

 but after some search a location was finally chosen, 400 yards up- 

 stream, and a level line 270 feet long was measured with a steel tape. 

 Observations from this gave the distance (3,855 feet) between 

 Stations A and B at the ends of the line. 



From these the position of the great boulder (pi. i, fig. i) on the 

 surface of the ice near the center of the glacier was determined. On 

 July 19 the downstream edge of the boulder was 2,440 feet distant 

 from Station A, and 2,510 feet distant from Station B, the elevation 

 of its base being 6,000 feet. The azimuths between the boulder and 

 the ends of the line were : from A, 39° 10', and from B, 38° 10'. It is 

 visible from Camp Station, and distinctly appears in plate 3, figure 2, 

 ly^e inches from the left edge on the ice profile. 



This boulder is the largest of many sizable erratics that are 

 scattered over different quarters of the tongue. They occur singly 

 and sometimes in pairs, surrounded by clean white ice. This gives 

 them good visibility from a distance and will render them valuable 

 markers for studies of the ice motion. The stone in question was 

 doubtless noticed by Dr. Collie in 1897, for it appears to be shown 

 in the illustration opposite page 62 in his " Climbs and Explorations 

 in the Canadian Rockies." He writes (page 55), " We noticed them 

 within a mile of the snout of the glacier and in 1902 they did not seem 

 to have moved much." The rock is now exactly a mile from the end 



