( l'^l ) 



vapours, luis a peculiar shape and siiows 1 hat retograde condensation 

 is \van(ini>'. 



Fj +Anthraquinono 

 (yolid) 



I 



ISO.. 



Fg -\- Anthra- 

 quinone (solid). 



/' 



^ 0^/ 0,1 03 ^,j^ 0,S 0,0 (J// O^i O O -/' 

 Elher. X Antliraqiiinone. 



X 



Fiff. 2a. 



The curve (i^f\ on tlie contmrv indicales a lolerahly strong retro- 

 grade soliditication. The curve e., ^'3 shows that here the solubility of 

 antliraquinone in ether decreases with increased |>ressnre. The curves 

 ^3 (^3 and (\ .v, are two portions of a continuous curve, of whicii the 

 partly not realizable intermediate i)art is schenialically represented 

 by a dotted curve. I propose to call this conliniioiis curve henceforth 

 Lsotkenn of solnbiliti/. 



Passing on to a higher temperature, we see that the y^-.r-section at 

 255° is still of the same type as that at 250°. At 2(50' (fig. 2A) 

 however, the situation is already considerai)ly changed; not oidy the 

 y>-.ï-loop C5 /i\ f's has become much larger, because the points e,^ and 

 ('r, have become more widely separated and /•,. has moved to higher 

 jn'essure, bid also it is clearly visible tiial the lefrogimle condensation, 

 which is still \vaiding here, will Iiave ap|»eared at a slightly higher 

 temperatui-e. 



Ill the part <j^ t\, though in a smaller degree than at 250", the 



