418 Mr. W. Mathews on Canon Moseley's views 



being obliged to return home, Mr. Reilly devoted three weeks 

 to this purpose, and has generously placed his notes at my 

 disposal. 



The spot selected for his first operations was a part of the 

 Glacier of Bionassay, where the stream is very slightly inclined, 

 and the central portion nearly level from side to side and free 

 from crevasses. The width of the glacier at this part was 320 

 yards, for 200 yards of which, measuring from the left bank, the 

 surilace was composed of " avalanche-ice without veined struc- 

 ture," the remaining 120 yards being ordinary glacier-ice. 

 • Mr^ Reilly bored the first hole about 70 yards from the right 

 bank of the glacier, and ranged, with a theodolite, a line 170 

 yards in length, terminating about 80 yards from the left bank. 

 This line was divided into seventeen equal spaces by holes bored 

 10 yards apart ; the line was ranged and staked on the 7th of 

 September. The holes were deepened from time to time as 

 the glacier- surface melted, and the final measurements made on. 

 the 27th, after an interval of twenty days. 



The results are exhibited in the following Table — the motion 

 on each side of No. 10, where the velocity was greatest, being 

 exhibited in parallel columns, the negative signs indicating 

 relative regressions of the ice at the points to which they refer :- — 



Right moiety. 



Left moiety. 



Stations. 



Absolute 



Relative 





Absolute 



Relative 





motion. 



motion. 





motion. 



motion. 





ft. in. 



in. 





ft. in. 



in. 



0. 



11 6-50 











1. 



10 11-60 



-6-90 









2. 



11 4 25 



4-65 









3. 



11 3-00 



-1-25 



17. 



11 0-50 





4. 



11 725 



4 25 



- 16. 



11 300 



2-50 



5. 



11 675 



-050 



15. 



11 700 



4-00 



6. 



11 5-25 



-1-50 



14. 



11 6-50 



-0 50 



7. 



11 6-50 



1-25 



13. 



11 8-50 



2-00 



8. 



11 600 



-0-50 



12. 



11 7*50 



-1-00 



9. 



11 900 



3 00 



11. 



11 700 



-0-50 



10. 



11 1000 



100 



10. 



11 1000 



300 



Here we have a superficial area of ice 170 yards in width 

 moving through a space of nearly 12 feet in twenty days, with 

 an advance of the centre during that interval only 10 inches in 

 excess of the sides, the differential motion at the side being 7 

 inches, and at the centre 1 inch in a width of 360 inches ; so 

 that two points an inch apart would in twenty-four hours move 

 past each other to the extent of a little less than the j^o'd °f ai1 

 inch at the sides, and the 7 qW of an inch at the centre of the 

 area under consideration* 



