﻿of the Descent of Glaciers by their Weight only. 369 

 Work of friction of ¥ p q Q on p q 



=dVj C0S .- -hm±rm ^^w^ « dx> 

 vj ^WV+v) cos »£ w+ , (< ,_^j^ 



Ti , m5 ,_ ^y/Q 3 + y)cos t r ^( a »«»- a »<3») -| 

 u 6 /cos t - 4 ^ |_ a _^ j, 



U 5 /CO S4 - .^^ cos, 



T2^ C0S 'J 



Substituting these values of U, TJ 1( U 2 , U 3 , U 4 , U 5 in equa- 

 tion (1 ) and reducing, 



a- i Wfl jf««+«a +^ 8^+^y)""»-W+ftr+yVco»» . f8 > 



/* - 6 tooA (« + «/3 + (3 ) fl ^ a , + a p +pi)+ ba z {j3i + p y + y , } (») 



By the measurements of Professor Tyndall on the Mer cle 

 Glace, 



*« = 699, *A = 136-8, ** = l-9375, t/3=*5416', 



fy = -2133', %w= 62-5, §/=-022, * = 4° 52'. 



Substituting which values, we obtain 



Equation (2), U sin c= 2657583 sin i. 



Equation (8), U 1= 89836. 



Equation (4), U 2 = 13263. 



Equation (5), U 3 = 1492. 



Equation (6), U 4 /cost= 54028 cos c. 



Equation (7), U 5 /cost= 30656 cost. 

 Equation (1), 



U sin t--(U 4 + U 5 ) /cost _ 2657583 situ — 84684cos* 

 fl ~ Uj + Ug+Ua ~~ 104591 ' W 



In the case of the Mer de Glace, t = 4° 52'; 



225458-84380 . 



••^= 104591 = 1 ' 3489 - ' • (10) 



* Phil. Trans, vol. cxlix. pp. 265 & 266. 



f Tyndall's ' Glaciers of the Alps/ p. 2.92. 



X The specific gravity of glacier-ice is assumed equal to that of water. 



§ By the experiments of Mr. G. Rennie. 



Phil. Mag. S. 4. Vol. 37. No. 250. May 1869. 2 B 



