852 



the one extremity on CQ and the otlier on AQ' and of the isolated 

 point B (fig. 4 — 6). 



On further increase of P boiiingpointcurves now arise, consisting 

 of two branches separated from one another. In the vicinity of B 

 a new branch is viz. formed with the one end on BQ and the 

 other on BQ' (fig. 4 — 6). On further increase of 7^ botii the branches 

 stiift towards one another and under a definite pressnre Px both 

 the branches come together in a point X. This point X is situated 

 1". on one of the sides BA or BC, 2". within the triangle; in the 

 first case A' coincides with Q or (/. Iji fig. 4 and 5 the two branches 

 come together in Q' , in fig. 6 in a poijit X within the triangle. 



Ill tig. 4 and 5 the boilingpointcnrve of the pressure Pq forms, 

 therefore, a single branch. From our previous considerations it follows 

 that this is curved as a parabola in (2' and touches the side BA in 

 this point. The temi)erature must increase in the direction of the 

 arrows along this curve in the vicinity of Q' . 



On lurther increas3 of pressure the boilingpointcnrve shifts from 

 point Q' (fig. 4 and 5) into the triangle and we may distinguish 

 two cases. Either it disappears in the point Q on the side 56' (fig. 4) 

 or it tonches the side BC in the point Q (fig. 5). In the latter case 

 it shifts on further increase of pressure from the point Q into the 

 triangle, so that a closed cnrve arises, whicii disappears in 7^ some- 

 where within the triangle. 



In fig. 6 the point X in which the two branches of the boiling- 

 pointcnrve come together, is situated within tlie triangle. Here we 

 have a case as was treated formerly in communication A^ (fig. 5). On 

 further increase of pressure again two branches are formed, separated 

 from one another, which are situated now quite different than at first 

 and on which the points of maximumpressnre are wanting. On further 

 increase of pressure the one disappears in Q and the other in Q' . 



Besides the diagrams drawn in figs. 4-6, several others may be 

 imagined. For instance we may assume that the two branches of 

 the boilingpointcnrve do not disappear in Q and Q' as in fig. 6, 

 but tliat they touch in these points the sides of the triangle. The 

 boilingpointcurves then consist of two branches separated from one 

 another, which are both closed, and of which the one disappears 

 in a point between Q and A' and the other in a point between 

 Q' and A^ 



We may consider now more in detail the boilingpointcurves in 

 the vicinity of the point B, as in this point x becomes = and 

 y — 0, we put : 



