Force and Osmotic Pressure. 381 



as previously) is 



RT(. 2 -t 1 )=RT(H-l)( 72 - 7l ). 

 But the area under the curve GHCE represents the value of 



| P^V=RT (W = RT f^~. 



Fi?. 1. 



1 \ 



\ \ 

 \ \ 

 \ \ 



\ \ 



\ \ 



\ \ 



kC 



\ 





E 



• ■ • v> 





B 









H C V 



Hence to get a graphical representation of the electromotive 

 force we must add to GHCE the rectangle OFGH and sub- 

 tract ODEC, leaving the figure FGED. The latter, however, 

 stands for the expression J YdF; and we therefore arrive at 

 the remarkable result that the electromotive force is not pro- 

 portional to the work of expansion \ PgTV but to the converse 

 integral, being exactly 



E = 



re 



T 



Jp, 



YdF. 



(3) 



(iii.) Solutions deviating from Boyle's Law. 



The above is the argument as it first occurred to me: but it 

 will be found that the results arrived at are independent of 

 one of the assumptions made, viz., that the osmotic pressure is 

 proportional to the concentration. If we do not assume that, 

 but, retaining the previous notation, write 

 P=RT*C, 



