5638 
F is in many respects comparable with point / in Fig. 2, also 
here a line FA for quasi-unary melting phenomena will appear 
(“line of the maxima” in the melting diagrams at different pres- 
sure values), hence we might call point /” the “minimum quasi 
unary melting point” of the system. As starting from /’ «5 —2, has 
a negative value whereas #s—«; remains positive; both numerator 
and denominator in equation (1) will also be negative; a further 
appearance of a maximum or a minimum is, therefore, excluded 
(compare § 2 last lines). Only when eualisation of phases takes 
place, (which involves a minimum in the Pe-figure from S —G or 
Gi—Z, equilibria) further remarkable points would be possible, such 
as a “maximum quasi-unary sublimation point” a minimum and a 
maximum on the three-phase line etc. 
The progressive change of these lines strongly reminds us of that 
of a compound without formation of mixed erystals but the configu- 
ration of Fig. 6 does not give us, however, an indication for the 
existence of a compound. On the contrary, an eventual decrease 
of the value #«g—«#z, which had such important consequences in § 4 
does not affect any peculiarity on the three-phase line, not even a 
reduction of erger, to zero in a maximum pressure would have 
that effect; only #g—ay in a minimum would modify the line, but 
even then the doubt would remain whether we had to do with a 
chemical compound or not. 
7. We must still refer in a few words to a system of the type 
d and /-carvoxim discussed in the previous communication. After 
the statement in § 6 it will be evident that the investigation of the 
three-phase line does not lead to a decision when the compound 
melts at a higher temperature than that of the components. But 
there is still another complication in a system of optic antipodes. It 
happens there that #g—ay, is zero at all concentrations. This is 
the case in the system d- and / a-pipecolin') albeit there occurs un- 
doubtedly a solid racemic compound *) in that system *). 
1) A. LADENBURG, Ber. deutsch. chem. Ges. 44. 676 (1911); H. R. Kuuvr, 
ibidem pg. 995. 
2) A. LADENBURG and SoBeckKi, ibidem 43, 2374 (1910). 
3) The fact that, in such a system, all G-L equilibria are quasi-unary is connect- 
ed with the peculiar small differences of the components; «j is there undoubtedly 
: : day, 
=d,, also bj =bz; also djz is evidently equal to a, for then —* —g 
da 
Ge ) (2 ) 
Òr-pr/g \deyr/L 
av 
db, 
and also —~ =0 and for 
we can simply write then 
36% 
