RESIDUO-CAPILLARY ATTRACTION. 229 



columns at the summits of spiculae of given shape and sixe will be as 

 (p — r)-, even when the dimensions of the spiculse are indefinitely less 

 than the sphere of sensible attraction. For, the attraction of a meniscus 

 bounded on one side by a plane surface, upon the conterminous normal 

 column, will in all cases be a definite integral depending on the shape 

 and size of the meniscus, and the demonstration of La Place, by which 

 he shows that the attraction of such a meniscus is the same whichever 

 way it be turned, is perfectly independent of its size and the shape of 

 its curved surface. 



Let then I be the attraction of any meniscus upon the conterminous 

 normal, the meniscus consisting of one mixture, and the normal of the 

 other; m, the attraction of the same meniscus when the meniscus and 

 column consist both of the first mixture; and n, the same thing when 

 they consist of the second mixture. Then reasoning exactly as in 

 No. (15), the moving force upon the column GF will be 2l—m — n; 

 and if (/), (m), (»), be the initial values of I, m, n, it may be shown 



exactly as before, that 2l—m — n = c/C_^ >.^g • {2(/) - (m) - (n)}, the 



theory of No. (11) being equally applicable in this case. Hence, how- 

 ever minute the spiculae may be, the moving force upon the central 

 column will, for spiculse of given shape, be as the square of the difference 

 of densities. 



This consideration applied to the theory of No. (25), gives it a 

 generality which renders it as satisfactory as can well be desired. 



J. POWER. 



Trinity Hall, 



Marck 29, 1834s 



Vol. V. Part II. Gg 



