113 



in connection with the absolute value found in tlie first or in tliê 

 sixth column. 



Besides tlie vapour pressure line of violet phosphorus, also that for 

 liquid phosphorus is indicated in fig. 4, from which it is seen how 

 the observed vapour pressures lie on the line drawn acoordin"- to 

 formula (li). 



JDD 3D0 HDD 600 ÜOD 



Fig. 3. 

 4. Conclusions. 



The result of this investigation is so important for this reason 

 that it was not known before whether there was any conneclion 

 between the licpiid wliife, and the liquid violet phosphorus. Bakhuis 

 RoozpiBOOM ') pointed out the possibility that the liquid white phos- 

 phorus had to be looked upon as supercooled liquid violet phosphorus, 

 but he also expressed the opinion that it might also be that the 

 phosphorus entirely agreed with the cyanogen, and that the vapour 

 pressure line of the liquid white phosphorus terminated below the 

 melting-point of the violet form in a critical point. 



Up to a short time ago we thought for three reasons that this 

 latter supposition of Bakhuis Roozeboom's would be the correct one. 

 First of all the shape of (he vapour pressure line of the liquid 

 white phosphorus found some lime ago pointed to the fact that this 

 line could not be the prolongation of that of the liquid violet one. 

 In the second place it could be calculated from the determinations 

 of Aston and Ramsay') of the surface tension that (he licpad white 

 phosphorus must reach its critical point at ± 422°. And in the third 



1) Lehrbucli Heterog. Gleicligewichle 171 and 176. 

 -) Jouni Cliem. Soc. 65, 17.> (1894). 



Proceedings Royal Acad. Amsterdam. Vol. XVIII. 



