1844.] MOTION OF A GLACIER OF THE SECOND ORDER. 67 



have observed coincidences in our views which he appears not 

 to have noticed ; and he would probably have hesitated before 

 laying down so broadly as he has done an objection to the 

 Viscous Theory, very easily refuted, and some peculiar views 

 which he considers distinctive of his manner of considering the 

 subject, from De Saussure's and my own. I shall probably, on 

 another occasion, endeavour to show that, by following out his 

 own principles, the results must inevitably merge in mine, when 

 what is inadmissible shall have been subtracted. 



P. 8. The influence of the Dimension, Slope, and absolute 

 Elevation (or surrounding temperature) of glaciers upon their 

 motion, is a matter of observation in detail which offers no 

 peculiar difficulty, and which deserves to be extended. Having 

 measured the rate of motion of perhaps the largest glacier in 

 Switzerland (the Aletsch), I have also measured one of the 

 smallest, a glacier of the second order, near the Hospice of the 

 Simplon, almost 8000 feet above the sea, and not many hundred 

 feet in length. The velocity was little more than an inch in 

 twenty-four hours, a result corresponding with the extreme 

 dryness of the neve at that elevation, indicated by the very 

 trifling issue of water from beneath, and to the insignificant 

 vertical pressure of so small a mass, notwithstanding its consi- 

 derable slope. A similar result, it must be owned, might be 

 expected in this case upon almost any theory. 



