( 840 j 



#1 



which is negative in the critical points. It' in this case we draw 



dx 



the line — — = with a top, either at x = 0, or at a small value 

 dv> 



of x the curve - - = 0, which is chiefly restricted to the left side 

 dx* 



d*y 



0, and on the 



of the ?;,.r-figure, lies partly outside the curve 



small volumes. If we now apply the reasoning of p. 737 etc. also 



d*ip 



in this case, when we had the reversed state as far as — — = is 



dv 



concerned, we conclude that for large values of x the spinodal curve 



d*ti> 

 does not move for away from — =0, hut that it is forced back 



dv 



d*ip 

 to smaller volumes for those values of x, where — is negative, 



dx 



' /2 'f' i „ 



and draws again very near to —— = with very small values ot x. 



dv 



Naturally the course of the (/-lines in connection with the course of 



the ^-lines must indicate this. 



The course of the />-lines for 

 this case must be derived from 

 the right side of fig. 1, from which 

 appears at the same time that the 



curve = occurs, but with 



d.cdv 



sensibly smaller volumes than 



those of 



• Ir 



0. And the course 



of the (/-lines is then indicated by 

 tig. 5 or perhaps sometimes by 

 tig. 6. In fig. 12 a couple of p- 

 lines have been drawn and a q- 

 line which touches these />lines, 

 which lines yield, therefore, points 

 for the spinodal curve. Here again 

 three plaitpoints are to be expected : 1 st . a realisable plaitpoint P 1 



above the curve = 0, 2 nd . a hidden plaitpoint P 3 on the left of 



dx* 



- == and above - — = 0, and 3 rd . the ordinary gas-liquid plait- 

 ed 2 dv* 



Fis. 12. 



