286 



which follows of course immediately from (11). Consequeritly curve 

 E and (i^,) have the same tangent in the invariant point. It follows 

 from (7) and (8) that they go also in the same direction of tempe- 

 rature and pressure, starting from (his point. When viz. ;., is 

 positive, then it follows from reaction (1) that curve (i^,) goes 

 towards higher temperatures, starling froiri tiie invariant point. As 

 it follows, however, from (7) that (dT),. is then positive also, con- 

 sequently curve E goes also towards higher T. When ).^ is negative, 

 then the curves (F^) and E go both towards lower T. It follows 

 from (2) and (8j that both curves have also the same direction of 

 pressure. 



In accordance with previous papers (Communication XXII) we, 

 tlierefore, find : when the new .substance occurs- in the phase Fi 

 only, then curve E coincides with curve (i^,). 



When the new substance occurs in the phases F^ and F, only, 

 then (12) passes into: 



X 



wherein /il=:—. Hence it follows: 



a;, 



\dT), {X,^K).,y\\dTj, \dTj, 



dK. . . (16) 



For fixing the ideas we assume that (-77^,) is greater than \ ~ry„ 



Now we distinguish two cases. 



1. P.; and i, have the same sign. The following is apparent from 



(15) and (16). When K changes from tot oo then ( ^7:, ) increases 



fdP\ f<IP\ . , . 



from -ttjt] to -77, without becoming maximum, minimum or 

 \(llj, \dlj, 



discontinuous. 



2. A, and ^^ have opposite sign. When A' changes from to c», then 



I — , J decreases without becoming maximum or minimum from 

 I—,] till — 00, then it proceeds discontinuously towards -|- 00 and 



afterwards it decreases to -jtt . 



When A; and ^, are both positive, then, in accordance with 

 reaction (1) botii curves {F^) and (F,) go towards higher tempera- 



19* 



