388 



On the Stinicture and Motion of Glaciers. 



together longitudinally and di'awn out laterally, bending with the 

 convexity downwards in consequence of the speedier flow of the 



central portions, until finally a system of bands was established 

 which appeared to be an exact miniature of those exhibited by 

 the glacier. On fig. 10 is a sketch of the bands observed upon 

 the surface of the mud, which, however, falls short of the beauty 

 and symmetry of the original. These experiments have been 

 varied in many ways, with the same general result. 



In conclusion we would remark, that our joint observations 

 upon the glaciers of Switzerland extended over a period of a few 

 days only. Guided by the experience of our predecessors, much 

 was seen even in this brief period ; bat many points of interest 

 first suggested themselves during the subsequent espei'imental 

 investigation. While, therefore, expressing our trust that the 

 substance of the foregoing memoir will be found in accordance 

 with future observation, we would also express our belief in the 

 necessity of such observation. Indeed the very introduction of 

 the principle of regelation, without which it may be doubted 

 whether the existence of a glacier would be at all possible, opens, 

 in itself, a new field of investigation. This and other questions 

 introduced in the foregoing pages, must, however, be discussed 

 with strict I'eference to the phsenomena as Nature presents them. 

 Much might be said even now upon these subjects, but the 

 known liability of the human mind to error when speculation is 

 substituted for observation, renders it safer to wait for more exact 

 knowledge, than to hazard opinions which an imperfect acquaint- 

 ance with the facts must necessarily render to some extent un- 

 certain. 



Royal Institution, January 1857. 



