RESIDUO-CAPILLARY ATTRACTION. 217 



which may be put under the form 



cA{p-r)-{-cB(p'-t^)*, 

 making 



^-(^)-(r)-r^) ^^^)+(^)-(r)L^^> {p) + {r) J}' 



and^=..^{(Z)-W^H 



{ip)-ir)rv' 2 r 



The agreement of theory with experiment, then, requires that 



jM) + jN) 

 (^) 2 



should be either nothing, or very small compared with 



14. When I first began to investigate this subject, certain con- 

 siderations, which it would be tedious to detail, led me to imagine 

 that the fluids might communicate in the interior of the tube, 

 forming a series of interlacing cylinders one within another, and I 

 found the forces which tended to protrude the cylinders into the 



opposite fluids, all multiplied by (L) — - — '-—^ — - . I therefore looked 



upon this expression as a measure of the tendency of the fluids to 

 mix, and this tendency being, as experience shows, very small in the 

 case of treacle and water, as well as in the case of the gummy 

 solutions and water, afforded an explanation why the force should 

 be so nearly proportional to the difference of densities, as Dutrochet's 



* I have elsewhere erroneously stated, that the residual force is c A(p—r) + c B(p—ry, 

 a mistake which I am glad to have this opportunity of correcting. 



