1845.] REMARKS ON THE CURVES OF DISTORSION. 115 



be seen that they were fifty feet apart in the direction of the 

 length of the glacier, and that a line joining their extremities 

 passed eight feet nearer the centre of the glacier than the point 

 Q, thus almost coinciding with the point of contrary flexure, 

 which was evidently occasioned by a slightly superior advance 

 of the mass of ice on which Q was placed, thus insulated in 

 some degree between the two fissures. This enables us to 

 transfer the origin of our curve to a point of undoubted solidity, 

 namely, the fourth station, from which point it swells with the 

 regularity which has been described, and which establishes the 

 compactness of the ice experimented on in the most convincing 

 manner. 



Thirdly. The curves reckoned from the origin, thus experi- 

 mentally indicated, show, in a beautiful manner, the convexity 

 in the direction of the glacier motion before alluded to, which 

 is singularly striking, considering the shortness of the space in 

 which it is developed with nearly mathematical precision, being 

 only about ^Vth O f the breadth of the glacier in this place (see 

 ground-plan, Plate III. fig. 1. Even an inspection of the curves 

 (Plate IX. fig. 2 of Phil. Trans.) can faintly convey the impression 

 made upon my own mind, when, upon the 26th of August, I placed 

 the theodolite for the last time over station Q, and caused the 

 vertical wire to pass in front of the line of pins bent into the 

 convex shape by the relative motion of six days' continuance. 

 Thus seen in foreshortened perspective, the eye would in an in- 

 stant have seized an abrupt motion or discontinuity of the line, 

 but " the appearance of the curve they formed was beautiful ; 

 the whole line of pins was deviated from the visual* line QQ1, 

 by an angle equal to 1245 inches, seen at a distance of ninety 

 feet, or about 40 ', and besides this, the pins lay in a beautiful 

 and nearly continuous curve, presenting its convexity towards 

 the valley, and decidedly without any great step or start. 

 This was beautifully seen when I directed the vertical wire of 

 the theodolite upon the forty-fifth pin, and caused it to describe 



* [Misprinted usual.'] 



