678 



tlie preceding commnnioation. a 7^7-rigLire is possible as fig. 8 shows. 

 Tiiese considerations open our eyes to the possibility that enantiotropy 

 occurs under higher pressure, notwithstanding the phenomenon of 

 monotropy is not fonnd under the vapour pressure. 



Amsterdam., June 25, 1914. Anonj. Chem. Laboratory 



of the University. 



Chemistry. — '^On the vapour pressure lines of the system 

 phosphorus.'' II. By Prof. A. Smits and S. C. Bokhokst. 

 (Communicated by Prof. J. D. van ükr Waals). 



(ComaiLinicalcd in the meeting of Sept. 126, 1914). 



Tlie continued investigation of the [)hosphorus purposed to decide 

 with certainty wlietlier the red and the violet phosphoi'us must be 

 regarded as two different moditications exhibiting the phenomenon 

 of enantiotropy, as seemed to follow from Jolibois' ') researches and 

 also from our first investigations. 



Confining ourselves to the communication of the result we can 

 state with certainty that the supposed i)oint of transition between 

 red and violet phosphorus does not exist, and that only one solid 

 stable modification of the phosphorus has been found, which is violet 

 in coarser crystalline state, but red in a more finely divided state. 



The vapour tensions of different phosphorus preparations approach 

 to amounts which form one continuous vapour pressure line, when 

 the heating is long continued. 



An apparent discontinuity may arise under definite circumstances 

 in consequence of too rapid heating. If namely, the preparation at 

 lower temperature contains too much of the more volatile pseudo- 

 component, too high vapour pressures are observed at these lower 

 temperatures, in consequence of the not setting in of the internal 

 equilibrium. In the neighbourhood of 450°, however, the setting in 

 of the internal equilibrium becomes appreciable, and this transformation 

 being attended with a diminution of the vapour pressure, the vapour 

 pressure line will present a course that reminds of a discontinuity. 

 When we worked very slowly and started from states which could 

 only differ little from internal equilibrium states, any discontinuity 

 had, however, disappeared. 



At the same time this investigation furnished a fine confirmation 



^) G. R. 149, 287 a909; and 151, 382 (1910). 



