( 841 ) 

 point l\ on the lett of = 0, but shifted lo the side of (lie small 



(I r" 



volumes. Now il is lo be expected that the value of p in the first 

 mentioned plaitpoint is smaller than in the last mentioned. For T/ : 

 strongly rising, the pressure strongly decreases when we pass along 



the curve — - to the right — and only if = should strongly 



dv* dx* 



project above = we should enter the region of high pressures. 



The hidden plaitpoint has, of course, far lower pressure than the 

 two others. The value of x for the first mentioned plaitpoint is larger 

 than that for the hidden plaitpoint. The gas-liquid plaitpoint has the 

 smallest value of x. Proceeding along the spinodal curve we get a 

 course of p, as has been previously drawn by me. (See These Proc. 



March 1905 p. 626). If T is made to increase, = contracts. 



dv* 



The top moves to the right, and reaches a position, in which - 



das* 



is negative for the critical circumstances. But this means that the 



gas-liquid plaitpoint and the hidden plaitpoint have coincided already 



before. When they coincide we have again, as we observed p. 744 



dv\ fdv\ fd*v\ fd 2 v\ fd s v\ Sd*v\ 



sirU); U?Jrl*ir U4 = w), After ,l,is coin " 



ciding we have again a simple plait with a simple plaitpoint. But 

 the plaitpoint lies far more to the left than would be the case if the 



curve = did not exist any longer, and it also has a much 



das % 



larger pressure. With further rise of T nothing of importance is to 



d 2 ip 

 be expected. For neither the fact that — = lies quite outside 



d, 



= 0, nor that = vanishes, gives rise to new phenomena, 



i/v 2 dx* 



because this takes entirely place in the unstable region. If we now 

 draw either the value of the plaitpoint temperature or of the plait- 

 point pressure as function of on, and if we restrict ourselves to the 

 realisable quantities, so excluding the hidden ones, this line separates 

 into two detached parts. The right pari begins at that value of x, 

 in which the plaitpoint P 1 possesses a pressure large enough to show 

 itself on the binodal curve of the plait whose plaitpoint is P t , and 

 passes then to x = l. The left part begins at x = } and disappears 

 before 1\ and P s coincide, namely, when P s lies on the binodal 

 line, of which i J , is then the plaitpoint. 



