104 VISCOUS THEORY OF GLACIER MOTION. [1845. 



would be found to become a continuous curve, and that no other 

 system of fissures could be found in the glacier satisfying the 

 mechanical postulate of the greater velocity of the central parts 

 of the glacier, than the ribboned structure of the ice, which I 

 had already pointed out as resulting from a forced separation of 

 the semi-rigid ice, at a vast, though finite, number of points in 

 the breadth of the glacier, and which I showed to exist exactly 

 in the direction required for releasing the mass from the tension 

 induced by the gravity of its parts. 



Having gone to Chamouni a few days later, I looked out 

 for a place where the ice should be as compact as possible, 

 wholly devoid of open fissures, and if possible continuous up to 

 the bank. This latter condition I found it impossible to fulfil 

 on the Mer de Glace, at least without ascending to the neve, 

 which might be objected to as less rigid than the glacier proper. 

 The former condition was well satisfied in a sort of bay on the 

 west side of the Mer de Glace between the Angle and Trelaporte, 

 exactly under the little glacier of Charmoz. The part adjoining 

 the western shore of the glacier is indeed highly crevassed, and 

 therefore unfit for this experiment ; but at the distance of fifty 

 or sixty yards from the moraine it becomes remarkably flat and 

 compact for a space of about seventy yards in width, and several 

 hundred yards in length, throughout which space there is not a 

 single open crevasse. Now this compact area of ice presents 

 the veined structure in a nearly longitudinal direction, with a 

 degree of delicacy and distinctness not to be found in any other 

 part of this glacier (as I had already remarked in my Travels, 

 p. 159), and it contains no other trace of a system of longitu- 

 dinal fissures or lines of separation of any kind, which could 

 render mechanically possible the distortion of this flat compact 

 surface of so great an extent. Now I have always observed 

 that the veined structure near the side of a glacier is best de- 

 veloped where the ice is least crevassed, or the continuity of 

 the mass most perfect; a fact stated and referred to its true 

 cause from the first date of my speculations on the origin of the 

 blue veins, in the following words : " The veined structure 



