( 713 ) 

 so that we find : 



dT RT' 1 2 



T- = TT-. 7, (11) 



da 

 In tliis Q is again = 7 + « /. — ,f (1 — x) — A. After substitution of 



dx 



da 

 the just found value for — , tliis becomes: 

 •* dx 



2—.V 

 Q^qJrct- X • . . (12) 



For .1' =: (11) becomes now: 



('I)=_ëll = -JE,- „H 



\(l'V Jo Qo ? + «0 ^ 



So the melting-point curve has now also at 7'^ T» a perfectly 

 normal course. 



For practical purposes we can determine more or less accurately 



the value of «„ from the approximate equation (Sa) (for small values 



of sr), which according to (7j renders also an estimation of Tab possible. 



The value of Qp must then of course be known. It can, however, 



also be calculated from the accurate determination of the initial course 



of T^B (with indifferent admixture), according to equation (11a). 



dT 

 If we then determine -— once more for that same line for x = 0,1 



d,v 



or 0,2 e. g., we can lind Q by means of (11), i. e. 



(l-a).v 



q 4- « X — « X , 



2 — « X 



supposing that we may put a = «„ by fii'st approximation. We find 

 then by subtraction of the above found value of 9 + "0^^ ths value 



<5f "o''- ~i) "' — ) so that of X separately'. Also q is then separatel}- 



2 — «„ X 



known. 



Appendu. The approximate equations (5") and (5') might also 

 have been derived from : 



rr. ., A^ï'A A'''ï^ A^'ï'A 



With (5") we fmd tlieii casih from the value (8) for — , that 



dx 



