1004 
pressure of 4000 kg. the violet phosphorus is the stable modification. 
When the former experiment was repeated only with this difference 
that instead of to 4000 kg. the white phosphorus was compressed 
to 12000 ke, black phosphorus was formed. It seems not too hazard- 
ous to derive from this that there exists a transition point between 
violet and black phosphorus and that this must lie at 200° C. 
between 4000 and 12000 kg. 
Now it is not be denied that this view is attended with difficulties, 
though they are not such as to make the above view untenable. 
These difficulties consist in this that all attempts made by Dr. 
BRIDGMAN to convert violet phosphorus into black, have failed. Violet 
phosphorus was mixed with a small quantity of iodine and then 
compressed at 200° C. to a pressure of 12500 kg, for 5°/, hours, 
without any conversion to black phosphorus taking place. 
He has further made this experiment; violet phosphorus was com- 
pressed to 12500 kg. at 200° C. in contact with white phosphorus 
in the hope that when black phosphorus transformed to black phos- 
phorus, the same thing would also take place with the violet, but 
the result was negative. White phosphorus was converted to black, 
but the violet remained unchanged. 
This, now, is undoubtedly surprising, especially for those who 
have never made a particular study of the phosphorus, and yet 
this result is not in contradiction with what has been found tor 
phosphorus of late. 
Experiment has taught that the internal transformations of the solid 
violet phosphorus only proceed with appreciable velocity at tempe- 
ratures above 400° ©, so that it is not astonishing that at 200° C. 
and at a pressure of 12500 kg. the transformation of violet to black 
phosphorus, which is accompanied with a chemical reaction, is not 
to be realized, though increase of pressure makes the velocity of 
reaction increase. 
That under the same circumstances of temperature and pressure 
the white liquid phosphorus is indeed, converted into black phos- 
phorus is not astonishing, as here the formation of nuclei in a strongly 
metastable /iguid is concerned. This process, which is proceeded by 
a chemical reaction in the liquid, can take place with great velocity, 
whereas the conversion of the solid violet into the solid black phase, 
for which a reaction in the solid phase must take place, does not 
take place appreciably. The facts stated by Dr. BRIDGMAN are remark- 
able, but they are not in conflict with what bas become known 
about the violet phosphorus-of late. 
When we succeed in subjecting the violet phosphorus to a higher 
