1901-2.] Causes of Formation of Amorphous Sulphur. 343 
38*5 per cent. Under these conditions, long continuance of the 
treatment did not cause any reduction in the yield. Addition 
of powdered glacial phosphoric acid had the same effect as these 
gases (37 ’3 per cent.). 
On the other hand, certain other gases, when used from the 
beginning of the heating, seemed to prevent the formation of the 
amorphous sulphur. Nitrogen gave 4 ’7 per cent., carbon dioxide 
4’5 per cent., hydrogen sulphide 0'8 per cent., ammonia 0 per cent. 
These gases also reduced the quantity to the same minima when, 
by use of air or sulphur dioxide, the larger amounts had already 
been formed. This remarkable fact was confirmed by repeated 
trial. In the case of phosphoric acid, however, treatment with 
carbon dioxide did not reduce the proportion, presumably because 
this acid is non-volatile. Conversely, air and sulphur dioxide 
restored the amorphous sulphur, which had already been destroyed 
by treatment with carbon dioxide. A little powdered potassium 
hydroxide had the same effect as the second class of gases. 
From these observations it may he inferred that absolutely pure 
sulphur would altogether lack the power to form amorphous sulphur. 
This work is being continued. The obviously cognate question 
of the supposed rule that sulphur precipitated from acid solutions 
is amorphous, and from neutral solutions is crystalline, will be 
examined. It is not advisable to offer any theory until further 
work has been done. 
( Issued separately November 15, 1902.) 
