1850.] CONFIDENCE DUE TO BALMAT's OBSERVATIONS. 223 



the great influence of the melting snows in imparting fluidity to 

 the glacier masses. I do not mean that the comparison leads 

 always to consistent results. I do not think that the causes 

 of the comparative acceleration of one glacier and retardation 

 of another have yet been clearly brought out, though I conceive 

 that accurate local observations, combined with such measure- 

 ments, would gradually but surely unveil them. Nor do I 

 mean to affirm that measurements made with so much labour 

 and trouble, and under circumstances even of personal danger 

 at certain seasons of the year, are irreproachable in point of 

 accuracy. I think it even probable that oversights have oc- 

 curred ; but I have very strong reason for confiding in the 

 absolute fidelity with which the observations have been made 

 and transmitted to me. Circumstances have transpired since 

 my last publication which increase this confidence ; and I should 

 be ungrateful if I did not once more publicly acknowledge, 

 whilst giving to the world the sequel of observations made 

 under such circumstances that their resumption is scarcely pro- 

 bable, the lasting obligations which I owe to the zeal, fidelity, 

 and disinterestedness of my worthy though humble friend and 

 guide. 



