( 244 ) 



triple point, added aiithrarpunone in solid condition will not pass 

 into the \aponi- stale. Tlien ,('.<,. = 1 and ./■,/!= 0. We ^et : 



(IT i\l-Vl—'ri(rj~Vs) 



The quantity / is now the latent heat of liquefaction of antlira- 

 qninone. 



For vanishinii' value of ./■/ we liiul increase of /> witli 7\ as is 

 fonnd in case of equilil)rinni between lirpiid and vapour. In neither 

 of these cases the numerator can become eqnal to zero when a 

 small (pianlity of the second substance is added to the principal 

 substance. 



But I shall not enter into more particulars, ]ior discuss the treat- 

 ment of special circumstances. If they are brought to light by the 

 experiment, they can necessarily be derived from the above formulae. 

 Kor shall 1 discuss the /•,./■, 7'cui'N(>s, w liicji would lead to greater 

 digressions. For thi> discussion we should ha\e to malce use of 

 two equations, of which that toi- the coexistence of liipnd and vapour 

 occurs in ('out. 11. p. 104. Foi the /•,.' ])rojection of the three- 

 phase-equilibi-iuui \ye gel for autlu-aquiuoue and (^flier two separate 

 branches, hing outside tlic limits of the uiaximum and the minimum 

 value of./- mentioned above When these two values of ,r coijicide, 

 these branches meet, intersecting at an acute angle: at further 

 moditication the two r,.r. curves, \\a. those lor \U[\\U\ and >apour, 

 will yield a highest and a lowest value for the noIuuic: at any 

 case the /•,'■ ciu-ve for the vapour ])hase. As appeared in an oi-al 

 communication. Dr. SMrrs had already ai-rived at this result. 



I shall conclude with |)oiutiu,u' out. lliat ca.ses of jrtrfh/irn/c 

 .sollilific'i/ioi/ must repeatedly occur, boih \vhen the temperature is 

 kept constant with change of pressure and wheii the pressure is 

 kept constant with change of temperature. 



Chemistry. — "YV/c pcssi/z/c /'onus a/ the incltuKjiiolnt-rui-ri' for huKirij 

 jiiiiiiires of isoii'Oi'plions substances." By J. J. van Laar. 

 (2"*^ communication). (Communicated by Prof. H. W. Bakhuis 

 Roozkboom). 



i. Mv investigations concerning the possible forms of the melting- 

 point-curve for binary mixtures of isomorphous substances, c(unmu- 

 nicated in the Proceedings of the meeting of the 27''^ of June 1903, 

 have, apart from the^ ditferent theoretical considerations, led to the 

 following practical results. 



