AMMONIA. 
gen and hydrogen. The oxygen of the water was fur 
nished by the acid ; the other products must have been 
furnished by the ammonia, which has disappeared. 
Ammonia, therefore, must be composed of azot and 
hydrogen. It follows from Mr Berthollet’s experi 
ments, that ammonia is composed of 121 parts of azot 
and 29 of hydrogen. According to Dr Austin, it is 
composed of 121 parts of azot and 32 of hydrogen. 
Hence 100 parts of ammonia, are composed of about 80 
parts of azot and 20 of hydrogen. The experiments 
of Berthollet have been still farther confirmed by those 
made more lately by Mr Davyt. 
The component parts of ammonia being thus ascer 
tained, nothing was wanting to render the theory com 
plete but the combining of these substances together, 
and the forming of ammonia by art. Dr Austin mix 
ed hydrogen and azotic gas together in the proper pro 
portions, and endeavoured to make them combine by 
the application of heat, by electricity, and by cold; but 
he found, that while these two substances were in a 
gaseous state, they could not be combined by any me 
thod which he could devise. It could not be doubted, 
however, that the combination often takes place when 
these bodies are presented to each other in a different 
form. Dr Priestleyt and Mr Kirwan§ had actually 
produced it even before its composition was known. 
Accordingly Dr Austin found, that when tin is moist 
ened with nitric acid, and after being allowed to digest 
for a minute or two, a little potass or lime is added, 
Researcbes, p. 56. 
E Phl. Trans. 1788. 
On Hpatie Air, § i. 
1 On Air, ii. 41. 
413 
Chap. I.