which becomes a violet coloured Gas by Heat, 8 1 
this body, it is necessary to suppose the existence of hydrogen, 
or of water in the substance, or of hydrogen in phosphorus. 
I used the substance distilled through quick lime, which 
there is every reason to believe would absorb all the water 
united to it : in this case the acid gas, which gave hydrogen 
when decomposed by mercury, was produced in much smaller 
quantities; but, when the substance was moistened, the gas 
was afforded in very large .quantities. It is probable, that a 
little hydrogen existing in the phosphorus, and which appears 
when that substance is acted on by Voltaic electricity, may 
influence the result ; but I am inclined to attribute it princi- 
pally to the moisture adhering to the substance, and I have 
never been able to produce more gas from the fusible com- 
pound by distilling it with a new quantity of phosphorus. 
When the fusible compound of the substance with phos- 
phorus is distilled with a small quantity of water, the gas pro- 
duced seems to be of the same kind as that obtained by the 
action of heat during the combination, and both these gases 
when absorbed by water afford, wdien acted upon by nitrate 
of silver, the same product as that formed by the action of a 
solution of the substance in water on the same salt, 
I attempted to form a compound of the substance with hy- 
drogen directly, by heating it in several experiments to red- 
ness in a glass tube fllled with hydrogen. When the gas w^as 
moist, or when the tube contained vapour, a strong acid fluid 
was formed of a deep yellow colour. When the gas and the 
substance were dry, there was an expansion of volume, and 
on breaking the tube, fumes appeared similar to those pro- 
duced by the action of the gas formed during the union of 
phosphorus and the substance, and which precipitated in th^j 
MDCCCXIV. M 
