518 Dr. G. Bakker on the 



for this cohesion * 



1 SirfWdh )- \J' 



the potential function of the forces of cohesion being—/* ~, 



r 



We have also: 



Pv 



a V 2 J_(dJ\ 2 m 



8Trf\ 2 -$7rf\dh)' * * ' [) 



Remarking that 27rf\ 2 =af, 



X 2 /dV\ 2 



slsr) -*--? + -e (8) 



d 2 V 

 For the point of inflexion Q 1 we have ^r = ; hence 



Y + 2«p = (9) 



See equation (5). 



Moreover if p denotes the pressure in a homogeneous phase 

 with a density equal to the density in the considered point of 

 the capillary layer, we have 



p = 6-ap\ . . . . (10) 



Eliminating 6 and V between (7), (9), and (10), we get 



\ 2 /dV\ 2 

 latdh) =" 

 or 



P\~P being denoted by the distance SF in fig. (4). 



Although in a theory of capillary attraction, where use is 

 made of a potential function of the form 



J r 



the thickness of the capillary layer becomes infinite and the 

 V-curve of fig. 5 is asymptote to BB' and CC, we have 

 practically considered the capillary layer only as a layer for 

 which the gradient of the potential V cannot be neglected in 



* Phil. Mag. for Dec. 1906, p. 564. 

 t Loc. cit. p. 561. 



