1005 
pressure at a temperature of 400° or 500°, the conversion to black 
phosphorus can probably be realized, but an investigation at this 
high temperature probably brings great difficulties with it. 
In virtue of Dr. BripGman’s investigations and ours the part of 
the P,7’diagram that is of interest here can be schematically given 
as follows: 
e 
13000KG 
Fig. 5. 
S, = violet phosphorus 
S, = black 
6 =triple point of the violet P 
OI Ck 
The line df is the transition line between violet and black P. 
About this line the following remark may be made: Bripaman did 
not succeed in converting white phosphorus into the black modi- 
fication at 175°; even at a pressure of 13000 kg. the formation of 
black phosphorus failed to appear. This fact probably points to this 
that at 175° the transition pressure lies higher than 13000 kg. At 
200°, however, he succeeded in doing so, and from this it would 
follow that at this temperature the transition temperature lies already 
considerably below 13000 kg. 
7. Apparent contradictions. 
If we work quickly the black phosphorus, in the state in which 
