( l'« ) 



The object of the experimeiil \v;is to delerniiiie the />/-,/'-seetions 

 of the y>-.i•-^su^faee at different temperatures, and if possible also the 

 r-.i'-seetions of the ?"-,?'-^siirface. At the same time 1 should get to the 

 knowledge of some projeolions already spoken of in the prexious 

 paper, viz. the projections of the /)-.i'-^surfaee on the p-t and the 

 ^.I'-plane. I shall In-ieflv state the result here. 



Tn order to have the same succession as was chosen in Ihe prece- 

 ding communications, the y>-/-pi'oJeclion will be treated lirst. 



P 



lot 



9' 



do 



r 



60 



so 



JO 



o •^ /<fe /(jo 



f JO*' Ida 1^0 Lft> I/O lio tio ii^o Ziff i:,o r/o ISO 2 no Sen 



T 



iMg. 1. 



In llg. 1, ('<i represents the va|)onr pressure curve of |)ure ether 

 with the critical point in a (Jil3^ and o() atm.). ry> amNyr/ represent 

 the portions of the three |»hase curve wliich can be realized. Up to 

 193^ the three phase curve |)ractical]y coincides with the vapour 

 pressure curve ea of i)ure ether, in consecpience of the verv small 

 solubility of anthraquinone in ethci-. On the curve ap lie the })lait- 

 points of the unsaturated solutions of anthracpiinone in ether, and 

 p denotes the first plaitpoint of a saturated solution (203° and 43 atm.). 



The s('co)i(/ plaitpoint of a saturated solution of another concen- 

 tration lies in 7 (247° and 64 atm.) and on the curve gb lie the 

 plaitpoints of the second series of unsaturated solutions. Probably 

 this curve, which i-uns on to the critical i»oint of anthra(piinone, 

 has a maximum. 



