1S59.] on the determination of tie heights of Mountains. 313 



necting the nearest point of the sea, viz. the mouths of the Indus, 

 with the foot of the Kashmir Hills, running over a space of about 

 720 miles. 



8. In the case, then, of Mount Everest in the Darjeeling Hills, 

 the line of stations runs up due north over 360 miles to the foot of 

 the hills, from which the distance due north to the axis = 156 % 

 sec. 22° 30' = 168 miles. Suppose the stations along this line are 

 at 12 miles distance from each other in succession (which is about 

 the average "used in the Survey). There will be 30 such stations, 



at the distances 180, 192, 516 miles from the axis of the 



Himmalayas, measured due north. Hence at these places the de- 

 flections of the plumb-line (which vary inversely as the distance 

 from the axis) are 



168 168 168 



- 40", -40", 40". 



180 192 516 



INfow by para. 4 the difference of level caused by a deflection 

 40" = 12 miles % arc 40". 



40 



= 12 % 3 % 1760 % 7T = 12,3 feet. 



180 * 60 x 60 



Hence, the aggregate change of level between the foot of the 

 Darjeeling Hills, arising from this cause, 



14 14 14] 

 12.3 \ — +—+..... +— Keet. 



15 16 43 J 



{ 



11 1) 



172.2<! — + — + + — > 



15 16 43) 



= 172.2 % 1.098 = 189 feet. 



9. I will now find the change of level at the other extremity of 

 the range. The range there slightly inclines more to the north. 

 The axis of the Himmalayas may therefore be taken, for those 

 parts, to be a line drawn, as before, though a point in latitude 33° 

 of the meridian of Cape Comorin, but inclined 30° north of west. 

 This axis runs near Skardo ; and is, as before, about 156 miles from 

 the foot of the hills; which are about 720 miles from the mouths 



