6/6 [June 18, 



It may just be noticed (as a passing remark) that the total degree 

 in the general case is the coefficient of 



and the total weight the coefficient of the same argument in 



XIX. " Some Remarks appended to a Report on Mr. Hopkins's 

 Paper < On the Theory of the Motion of Glaciers'* ". By 

 Sir JOHN F. W. HERSCHEL, Bart., E.R.S. (Referee). Re- 

 ceived January 31, 1863. 



A few remarks arising out of the perusal of this paper may per- 

 haps not be considered as out of place on the present occasion. They 

 are not meant as in any way impugning the author's views of the 

 laws determining the fracture and disruption of glacier masses, or 

 their application to glacier-phenomena in general, but in relation to 

 the somewhat mysterious process of regelation itself, and to those 

 generally recognized and most remarkable facts of the gradual con- 

 version of snow into more or less transparent ice, and the reunion of 

 blocks and fissured or broken fragments, under the joint influence of 

 renewed pressure and of that process (whatever its nature), into conti- 

 nuous masses. If regelation be really a process of crystallization, it 

 seems exceedingly difficult to imagine how the molecules forming the 

 cementing layer between two juxtaposed surfaces can at once arrange 

 themselves conformably to the accidentally differing axial arrange- 

 ments of those of the two surfaces cemented. A macled crystal is 

 indeed a crystallographical possibility ; but then the axes of the two 

 individuals cohering by the macle-plane have to each other a definite 

 geometrical relation in space, as is well exemplified in the case of the 

 interrupting film in Iceland spar. At the temperature at which 

 "regelation" takes place (viz. the precise limit between the liquid 

 and solid states), it seems to me very possible that the cohesive forces 

 of the molecules of the cemented surfaces may be so nearly coun- 

 teracted as to bring those surfaces into what may be so far regarded 



* Read May 22, 1862. 



