( 618 ) 



may draw the above iiieiitioiicd coiiclusioii that tlie lower branch of 

 the melting point line — at least at the side of the rhombic mixed 

 crystals — is situated at a fairly considerable distance from the upper 



Wa 90 so 70 60 ■'to 30 ZO 10 o 



Fig. 9. Binary melting point lines of the three halogenised benzoic methyl esters. 



branch. Tliis change in direction of the cooling line is, however, so 

 slight, that the true situation of the point on the lower branch cannot 

 be indicated with certainty. 



The determination of the mixing limits by an investigation of the 

 solid phases, which are in equilibrium with solutions of known con- 

 tent, met with difficulties of an analytical character. An effort was, 

 therefore, made to determine tliose mixing limits by the crystallo- 

 graphic process. For that purpose solutions were prepared of mixtures 

 of the two esters, for instance of the cldoro- and the Zro/zio-ester, 



