976 
gives rise to a'too high pressure at the lower temperatures, where 
the establishment of the internal equilibrium takes place so exceed- 
ingly slowly. 
Besides it is possible, and this is probably the chief reason, that 
preparation 4 has not yet entirely assumed internal equilibrium at 
the temperature of preparation, and that therefore the preparation 
still contained somewhat too much of the volatile pseudo-component. 
This somewhat too much caused at those temperatures at which 
the internal equilibrium sets in most slowly, the greatest error and 
this will probably be the reason why the deviations are greatest at 
the lowest temperatures. Considered from this point of view also the 
much greater discrepancies which the preparations 2 and 3 exhibit 
at lower temperatures, can be accounted for in a plausible way. 
Hence it follows from our investigation about the vapour tension 
of the solid violet phosphorus that just as for the liquid violet phos- 
phorus 7'/n P represented as function of 7, yields a straight line, 
from which it therefore appears that the quantity Q in the equation: 
dnp __ Q 
dT RT 
ERE 
may be considered as a constant, so that we get through integration: 
Q 
DI GE et >. (2 
np RT + (2) 
or 
cages 
AD ecg ON (el 
As we have also done for the liquid violet phosphorus, we can 
again find the constant C graphically also here, as it is equal to the 
tangent of the angle a, which the line PnP as function of 7’ forms 
with the temperature axis, for: 
T lnp,—T,lnp, 
Ln 
We have T‚lnP,—=—1400 for 7,=343,5°4+-273°; T,nP,=3246,6 
for 7’, = 589,5° + 273°, from which follows C—= 18,889, a value 
which is about twice the value of the constant for the diguid violet 
phosphorus. 
C= = iga. 
When with this value for C we now calculate the quantity : 
for different temperatures, making use of the tables II and IV, we 
get what follows: 
