On definite Proportions. 43 
quantity of oxygen in ammonia, we shall find that ammonia 
must be composed of 
Base, oiisiegs oe 82-794 100°000 
Oxygen........ 47°286 89°623. 
A doubt however still remained respecting this result, 
Sal ammoniac, sprinkled on moist litmus paper, reddens it, 
as I have often observed, ina few seconds, as strongly as 
an acid would do; I therefore imagined that cal ammoniac 
might be a supersalt, although its taste is not acid. In or- 
der to try this, I dissolved some sal ammoniac in water, 
and tried to saturate it with caustic ammonia very much 
diluted, and of known specific gravity. But when I added 
a little tincture of litmus to the solution, it was but very 
slightly reddened, and a single drop of weak ammonia was 
more than sufficient to restore its blue colour. Sal am- 
moniac must therefore still be considered as a neutra! salt. 
The reddening of the litmus paper probably depends on a 
decomposition, in which the ammonia evaporates, and the 
substance that colours the litmus recovers its original red- 
ness, which had been changed to blue by the addition of 
lime or ashes in its preparation. Every attempt that I made 
to obtain a submuriate of ammonia completely failed, so 
that ammonia agrees with the other alkalies in being in- 
capable of combining with the muriatic acid in more than 
one proportion. 
After I had completed the series of my experiments on 
ammonia, I received, in May 1809, an essay obligingly 
sent me by Mr. Davy, in which he treats of the decom- 
pestiion of the base of ammonia by potassium. He had 
urnt 350 parts of potass with 205 of dry ammoniacal 2as. 
These 350 parts, according to the analysis above related, 
take up 73 of oxygen, Consequently the ammonia had 
contained 381 [354] per cent. of oxygen; although little 
dependence can be placed on this number: for Davy ob- 
served in these experiments an evolution of hydrogen gas, 
which was very nearly as great as if the potassium had been 
oxidated by water; and the product of the combustion of 
potassium in ammoniacal gas, besides hydrogen gas and 
potass, was also a combination of the basis of ammonia 
with potassium ina solid form. How then are we to ex- 
plain this evolution of hydrogen gas? Was it an effect of 
the decomposition of ammonia, so that nitrogen was con- 
densed with a smaller portion of hydrogen in the potas- 
sium? But in fact Davy obtained, by heating the mass, 
both these substances in the same proportion that they 
have in ammonid. Davy drew from his experiments the 
conclusion 
