( 466 ) 



pressure i]i the series of the liquid-vapour equilibria is but little 

 probable. At the moment there only seems an indication that the 

 case occurs with PH^ CI. 



If the line HM is situated much more towards the side of A it 

 might then also happen that the point H did not occur on the three- 

 phase line of the compound, but on that of the compound A, so 

 that branch 3 on this line follows on branch J and disappears, 

 from the three-phase lines of the compound. 



In a future communication I will discuss the boiling phenomena 

 of the saturated solutions corresponding with the said branches of 

 the three-phase lines. 



Crystallography. — "On Diphenylhydrazine , Hydrazobenzene 

 and Benzylanilme, and on the miscUnUty of the Ia,st two 

 with Azohenzene, Sti/bena and Dibenzyl in the solid .state.'' 

 By Dr. F. M. Jaeger. (Communicated by Prof. Bakhuis 

 Roozeboom). 



(Communicated in the meeting of October ï28, 1905). 



The following research was undertaken to furnish a new contri- 

 bution to the knowledge of the relation of the crystal-symmetry of 

 organic compounds and their power of yielding crystallised mixed 

 phases with each other '). Oi-iginally, it only aimed at the investigation 

 of Hydrazobenzene and BenzylaniUne in their connection with the 

 series, investigated by Brum, Garelli, Calzolari and Gorni, of 

 Azobenzene, Stilbene, Tolane, Dibenzyl and Benzylidetieaniline, but 

 afterwards, Biphenylhydrazine, which is isomeric \vith Hydrazobenzene 

 was also included. 



Diphenylhydrazine. 



(C« HJ, N— NH, ; melting point : 44° C. 



This compound, which I obtained through the kindness of Prof. 

 S. HooGEWERFF of Delft, crystallises from ligroine in the forzn of 

 colourless, large, lustrous crystals, which exhibit a rather varying aspect. 

 On exposure to light they rapidly assume a brown colour. 



1) Compare F. M- Jaeger, These Proc. VII. p. 658. 



