t isö ) 



Let lis now introduce the ratio of the critical pressures of thé 

 two components, \'iz. 



— ^^ jt. 



Vx 



6 

 Evidently' the relation t|) =r - exists, which changes (3) into: 



ÜX 



1\ I dx 



-= 2^^/ — ( 1 +- -f V, e\/-[\ - 7,1/- 



St V ^ J \ 



:t\ n 



or 



\ e ewz \ \\ 1/311 



jt üt 71 \y. 2 ztj n- \^2 2 ;:7r 



^ 1 /9Y3 1 A\ 

 jr :t y2 2 jry 



being the final expression for the molecular rise of the critical tem- 

 perature on the side of the lower critical temperature. 



Now a case of frequent occurrence is, that the critical pressures 

 of the two components differ little. If these pressures are the same, 

 :t=1, and (3(7) becomes: 



Lz=z6{e—i\ {Zb) 



whereas the former, approximated expression (see § 1) for this case 

 would yield: (if> is then —6) A — 6» — I— '~ \ 



So for the case .t = I the former expression must be multiplied 

 hy 6 ■=:-^, in order to yield the correct expression. 



A few instances will prove that it i§ no lonf/er necessary now to 

 double the molecular formula of the solvent. 



Aa Ji ig near 1 in most cases, and the formula (36) varies very 

 little with changes in the value of :7r, we shall use the formula 

 A=:/9(<9 — 1) for convenience, the sooner as the values of T^ (the 

 critical temperature of the dissolved substance) are all unknown, and 

 can be given only by approximation. 



Let us first take the four substances which Centnerszwer's expe- 

 riments induced me to calculate in the "Chemisch Weekbl." (I.e. p. 

 227—228). We shall now calculate the values of T^ from the values 



