1006 
we get it, would give a vapour tension line as indicated here by 
the dotted line gh, if the kerosene rests could be quite removed, 
from which it follows directly that this substance will not begin to 
melt until a temperature is reached higher than the triple point 
temperature of the violet form. 
This black phosphorus is, however, a disturbed metastable state, 
hence a state that is outside internal equilibrium. When this state 
is found in molten violet phosphorus at a temperature somewhat 
above 589.5°, there will be a tendency towards a more stable state, 
which can set in superficially at least without the substance trans- 
forming itself internally in consequence of this that, the liquid con- 
tinuing to be in internal equilibrium, « deposits on the solid phase, 
or that 3 passes from the solid phase into the liquid. If the former 
takes place more quickly than the latter. the solid substance increases 
at the expense of the liquid, if the latter takes place more quickly 
than the former, the liquid increases at the expense of the solid 
substance. In the former case we might get, in case of a sufficient 
quantity of the solid substance, the solidification of a stable liquid 
in internal equilibrium to a solid metastable substance being outside 
internal equilibrium. This would, however, not be in conflict witb 
the second law of Thermodynamics, because the state of the system, 
taken as a whole, would have passed into a state of smaller meta- 
stability. 
In the second case we get melting of the solid phase, and this is 
‚exactly what Dr. BRIDGMAN has observed. 
Now the internal transformations that take place at the stated 
temperature in the solid black phosphorus have not been mentioned. 
This setting in of the internal equilibrium leads to a lowering of 
the meltingpoint, so that also this process will eventually lead to a 
melting of the original black phosphorus. So long, however, as the 
solid substance continues to exist, the foregoing continues to hold. 
This phenomenon is in close connection with another which has 
also been mentioned in the introduction, and was also observed by 
Bripeman. Violet and black phosphorus were heated at 445° in the 
same vacuum. The disturbed black phosphorus having a smaller 
vapour tension at that temperature than the violet, it was expected 
that this black phosphorus would increase at the expense of the 
violet. The result was, however, that the black / slightly decreased 
in weight. 
Here too it is noteworthy that the black P tends to pass into a 
more stable form; this is possible even without internal transforma- 
tions taking place, when only, what is certainly the case here, 
