30 Prof. Maxwell on the Process of Diffusion of two or 

 and that of the second, 



-§f=# ^-p C") 



We have also the equation, derived from Props. XVI. and XVII., 



*j (Ap/,(M, + M 2 ) +BMM,- Cp,Z 2 M,) 



+ Bp,p 9 t. 1 M s (V,-V 8 )=0 (53) 



From these three equations we can eliminate V, and V„ and 

 find -j- in terms of p and -j-, so that we may write 



!=/(-!•) « 



Since the capacity of the tube is small compared with that of 



the vessels, we may consider -j- constant through the whole 



length of the tube. We may then solve the differential equation 

 in p and x\ and then making p=p v when x=0, and p—p\ 

 when x=c, and substituting for p x and p\ their values in terms 

 of y, we shall have a differential equation in y and t, which being 

 solved, will give the amount of gas diffused in a given time. 



The solution of these equations would be difficult unless we 

 assume relations among the quantities A, B, C, D, which are 

 not yet sufficiently established in the case of gases of different 

 density. Let us suppose that in a particular case the two gases 

 have the same density, and that the four quantities A, B, C, D 

 are all equal. 



The volume diffused, owing to the motion of agitation of the 

 particles, is then 



7 P dx VL > 



and that due to the motion of translation, or the interpenetration 

 of the two gases in opposite streams, is 



s dp kl 



The values of v are distributed according to the law of Prop. IV., 

 so that the mean value of v is — =, and that of - is ... , that 

 of k being \a*. The diffusions due to these two causes are 



