some new Objects in Chemical Philosophy. 71 
duce the same quantity of hydrogene from ammonia and water, 
the circumstance at first view, may be conceived favourable to 
the notion, that they contain hydrogene, which under common 
circumstances of combination, will be repellent to matter of the 
same kind ; but this is a superficial consideration of the subject, 
and the conclusion cannot be admitted ; for on the idea that in 
compounds containing gaseous matter, and perhaps compounds 
in general, the elements are combined in uniform proportions; 
then whenever bodies known to contain hydrogene, are de- 
composed by a metal, the quantities of hydrogene ought to be 
the same, or multiples of each other. Thus in the decompo- 
sition of ammonia by potassium and sodium, two of hydrogene, 
and one of mtrogene remain in combination, and one of hy- 
drogene is given off; and in the action of water on potassium 
to form potash, the same quantity of hydrogene ought to be 
expelled. From my analysis* of sulphuretted hydrogene, it 
nation, and i of hydrogene is set free. And it may be adduced as a strong argument 
in favour of the theory of definite proportions, that the quantity of the metals of the 
alkalies and nitrogene, in the fusible results, are in the same proportions as those in 
which they exist in the alkaline nitrates. 
* The composition may be deduced from the experiments in the last Bakerian lec- 
ture, which shew that it contains a volume of hydrogene equal to its own. If its 
specific gravity be taken as 35 grains, for 100 cubical inches, then it will consist of 
2.27 of hydrogene, and 32.73 of sulphur. When sulphuretted hydrogene is decomposed 
by common electricity, in very refined experiments, there is a slight diminution of 
volume, and the precipitated sulphur has a whitish tint, and probably contains a mi- 
nute quantity of hydrogene. V/hen it is decomposed by Voltaic sparks, the sulphur 
is precipitated in its common form, and there is no change of volume ; in the last 
case the sulphur is probably ignited at the moment of its production. In some ex- 
periments lately made in the laboratory of the Royal Institution, on arseniuretted and 
phosphuretted hydrogene, it was found that when these gasses were decomposed by 
electricity, there was no change in their volumes ; but neither the arsenic nor the 
phosphorus seemed to be thrown down in their common states j the phosphorus was 
