From tliis follows; 



( 295 ) 



bb\_ i Ö// ƒ ) dh 



dxjv I dv f—n\ dx 



d'b _ d'h f i" I db 



èxèv or"/— Jt\^/> dx 



If we substitute the values giveu above for MRT, v,{ I — — 



\ ov 



and — b ,r— in the expression for ( :-^- ) , we find for the value of 

 du' \dxdvjT 



the second term 2 . — and for the value of the third 



b dx / 



1 db f—4: 



term -f 



b dx f 



The value of ( t"^- 1 is then found equal to: 

 oxovJt 



\ 2a ( 1 da 1 db 

 dxèvjT v^ \ a dx b dx 



or 



ö>\ 2rt dT^ 



bxdvjT v^ Tydx 



d'p 



.dxdvjT ^^V. 



and for -^^ — -^— we find the simple value -— — ; so exactly the same 

 d'fi ^ 2\dx 



value as follows from the equation of state, in Avhich h is put 

 constant. This gives rise to the conjecture that this relation might 

 be found merely from thermo-djnamic relations independent of the 

 knowledge of the equation of state, and this is indeed the case. 



Let us consider the quantity ( ^] . It is equal to in the critical 



state of the component. Let us pass from liiis homogeneous 

 critical phase to another in which the volume has changed with 

 dv, the composition with dr, and the temperature with d7\ 



Let us put dT again equal to r/7/., so let us assume that the 

 mixture with d.v molecules of the second kind is again in an homo- 



geneous critical phase, then i -^ ] is again equal to 0. 



From: 



