( 177 ) 



o 

 Eth ar 



JC 



80 90 100 



Anthrachinon 



süliilioiis saturated \\\\\\ solid B i,s ([uito conformable \\'itli the l, 

 ,i'-projcction in fig. 4. The point y> lies at 195°, 95 "/„ ether and 

 5 "/n anthmchinon. The point y lias, as regards the concentration, 

 not yet exactly heen determined; I estimate it at TO"/,, ether and 

 30 "/n anthrachinon, the temi)erature lies at 241''. 



Ill order to elucidate the very remarkable phenomena we found, 

 I shall more closely consider the case that we start from a mixture 

 of ether and anthrachinon composed of 457,, ether and 55"/,, anllira- 

 cliinon (.1 lig. 5) and slowly heat this mixture. The (pianlity of 

 anthrachinon being so gi'eat and the volume rather small, we always 

 have below 195° excess of solid anthrachincm together with a saturated 

 solution and vapour. The concentration of the saturated solution 

 at rise of tem})eratnre moves along the line ry>. At about 195° we 

 reach the first critical temperature of the salural(Ml solution, w lieu 

 more heat is added the solution (lisa[)})ears and we get solid antlira- 

 chiiion -}- vapour. Apart from the continually increasing e\apoi-ation 

 of anthrachinon all remains unchanged u[) to about 241°. At this 

 temperature the critical |)henomen()n occurs again; whereas at yy the 

 liquid[)hase (llsaiijK'dri'd, here it is /(>r//#Y^f/ again '). On further rise of 

 temperature more anthrachinon is continually dissolving and along 



1) The points p and q can never be accurately reached in one experiment, a 

 very definite volume being required for every concenlralion. 



