Prof. J. D. Forbes's Sixteenth Letter on Glaciers. 171 



TABLE shewing the mean daily motion in inches of the Glaciers of 

 Chamouni deduced from, Balmafs Observations^ and continued 

 from, the Fourteenth Letter. 



In my former Letters I have taken occasion to mention 

 experiments and observations which have occurred from 

 time to time of a nature to confirm the fundamental hypo- 

 thesis of the quasi fluidity of the ice of glaciers on the great 

 scale, and I cannot doubt that these incidental remarks have 

 tended to diminish the natural incredulity with which that 

 theory was at first received in some quarters. I have now 

 to cite a fact of the same kind established by a French 

 experimenter, M. Person, who appears not to have had even 

 remotely in his mind the theory of glaciers when he an- 

 nounced the following fact, viz. : — That ice does not pass 

 aWuptly from the solid to the fluid state : That it begins to 



* Mean of Geneva and Great St Bernard. 



