RESIDUO-CAPILLARY ATTRACTION. 219 



He has also shown that the attraction of the meniscus is the 

 same whichever way it be turned. 



If the meniscus instead of consisting of the left hand fluid, (as 

 in the figure), consisted of the right hand fluid, the common boundary 

 being the plane BAD, there would be equilibrium, the column 

 AF being attracted by the right hand fluid, just as much as the 

 column AG is by the left. 



Since then the meniscus consists of the left hand fluid instead of 

 the right, the effect of the disturbance upon the column AF, tending 

 to draw it in the direction FA, is the attraction of the meniscus 

 upon AF, regarding it as consisting of the left hand fluid, minus 

 the attraction of the same meniscus regarding it as consisting of the 

 right, that is 



\R, ^ EJ \2 2 



supposing the left hand fluid to be the first mixture of No. (10), 

 or the lower fluid of No. (12). 



If then we estimate the effect in the direction AF, it is 



1 1\ /L M\ 



(1_ J_\ (± _M 



In the same way, the effect of the disturbance upon AG, in the 

 direction GA, is the attraction of the meniscus, regarded as consisting 

 of the left hand fluid, minus the attraction of the same meniscus, 

 regarded as consisting of the right, that is 



Ui "^ BJ • \2 ^ 



2 j- 



Hence the whole attraction in the direction GF, is 



{i^k){--^)- 



