RESIDUO-CAPILLARY ATTRACTION. 227 



These equations are equivalent to the following: 



VT = VT, and — = -^-—, — —. — ; 



p-irr p ^■r' 



whence 



v' ~ T ~ p' — r' ' p + r ' 



Let q be the volume of fluid absorbed in the times t and t', which 

 we have seen to be the same in each experiment; and let Q and Q' 

 be the quantities absorbed during a given time T, T not being so 

 great but that r, p, r' and p may be considered the same during this 

 interval. 



If then there be a law connecting the quantities absorbed in a given 

 time with the densities, we must regard this absorption in each experi- 

 ment as uniform during the time T\ 



.: Q : q y. T : T, 



and Q '. q V. T : r'\ 



... Qr = qT=Q'T'; 





+ / 



^ T p' — r' p + r 



■ The supposition we have made, as to the exactitude of type in the 

 two mixing processes, is particular ; but if there be a general law whicli 

 is applicable to all cases, that, must include the case supposed, and 

 therefore the result of the particular case must coincide with that of 

 the general law. If then there be such a law, it is expressed by the 

 proportion 



Q.Q .'. 



p-r . p-r 



"s/p + r ' \/p' + r' ' 



This being true in different experiments, must be true in different 

 stages of the same experiment. 



