( 707 ) 



of the melting-point curve at the bejrinning, it presents now an 

 almost horizontal course. 



Observation. 



Equation (5) enables us also to compute the melting-point tem- 

 perature Tab of the unsplit compound (i. e. nnsplit in tlic liquid 

 phase), (of. fig. 1). 



Then we have namely « = 0, ,v = 0, and we get, supposing 



Ctab = «0 : 



from which follows: 



1 1 /i , 1 + «„ 

 T-^1^ %/r^^ (7) 



4. We shall now derive the general expression for — all over 



the line 2\ A, in which it is only supposed that we have to do 



with ideal mixtures in the liquid phase, so that ihe terms, referring 



to the influence inter se of the different components, are again left 



out. But besides on x, a will now also depend on T. 



In two different ways we can arrive at the correct expression 



dT 

 for — . 



ax 



First of all by total diflerentiation of the equation (5) with rcsjject 



to T. We get then, calling the fraction -^ — = c-. 



1 + « (1 - *•) " 



f d log c„ \ /d log cA cLv^ _ jj^ 



\ dT J^y dx )Tdï'~RT'' 



hence 



d log Cj 



dT d.v 



da; q d log c,, 



Rf^ dT 



d log Cj d log c„ d log c da 



Now ~ = — \ — — 



ax Ox Oct dx 



1 «_ ^ C 1 \ — x \dn 



l-x \-\-a{\—x)J \ l-« \j^a{l — x)Jdx 

 1 2-.r da 



(l-.i')(l + «(l-.i-)) (l-a)(l + «(l-a'))c/*' 



