Intelligence and Miscellaneous Articles. 495 
nents gives evidently 
. 
T Tv 
h ee 
ence é ( lag ar 
and ultimately, FAG) Fig - 0008 <0 F soe : 
because it is evident, by the nature of the question, that while v in- 
creases from 0 to a the function f(v) increases therewith, and 
therefore could not be equal thereto for all values of vy commensurable 
with = unless it had the same property also for all intermediate 
incommensurable values. We find, therefore, that for all values of 
the component forces x and y, the equation 
SE Ga Oleg wre anaes eae, Bln (C.) 
holds good; that is, the resultant force coincides in direction with 
the diagonal of the rectangle constructed with lines representing « 
and y as sides. 
The other part of the known law of the composition of forces, 
namely, that this resultant is represented also in magnitude by the 
same diagonal, may easily be proved by the process of the Mécanique 
Céleste, which, in the present notation, corresponds to making 
dat ssa) agg! atta an” tee a 
and therefore gives 
24 42 
p = ae party 
But the demonstration above assigned for the law of the direction 
of the resultant, appears to Sir William Hamilton to be new. 
LXXXIII. Intelligence and Miscellaneous Articles. 
ON THE THEORY OF GLACIERS, WITH REFERENCE TO A FORMER 
COMMUNICATION. BY J. SUTHERLAND, M.D. 
To the Editors of the Philosophical Magazine and Journal. 
GENTLEMEN, 
| bp the last Number of the Philosophical Magazine there is a short 
abstract of a paper on the theory of glaciers read by me before 
the Liverpool Literary and Philosophical Society on the 14th of 
November 1842, and which was forwarded to you at my request by the 
Secretary. ‘The object of the paper was to prove that the discoveries 
of M. Agassiz, in regard to the infiltration of water into glacier ice, 
might be made the basis of a theory which would afford an explana- 
tion of all the known facts in regard to glacier motion. I stated 
the chief of these facts, and amongst others mentioned Professor 
Forbes’s discovery of a motion in glaciers similar to that of fluids, 
