1819.] and on some other Subjects of Chemical Theory. 291 
they have none of the properties which would be looked for in 
such a combination ; they have no acidity, or if any appear in 
one of the compounds with phosphorus, it is to a very limited 
and doubtful extent; and they are substances even which have 
little energy of chemical action. In the new doctrine they are 
considered as compounds of chlorine with their bases, sulphur, 
and phosphorus. Of course, as these bases form powerful acids 
with oxygen, and as chlorine is considered as an element of 
similar agency as oxygen, communicating similar powers, and 
conferring acidity even on hydrogen, they might, with not less 
reason than on the other doctrine, be expected to be acids of 
the greatest strength. The view I have stated accounts for their 
characters. They are ternary compounds, of the radical of 
mutiatic acid with the particular inflammable—sulphur, or phos- 
phorus, with oxygen. The oxygen is not in sufficient quantity 
to communicate acidity, or, in one of the combinations of phos- 
phorus, does so only to a very slight extent. But when water 
is added, a sufficient proportion of oxygen is supplied to produce 
this result, and the acidity is exalted by the corresponding 
hydrogen entering into the combination. What has been called’ 
phosgene gas, procured under certain circumstances from the 
action of oxymuriatic gas and carbonic oxide, may be regarded 
as of a similar nature,: the agency of a small portion of water or 
of hydrogen being probably essential to its formation, a circum- 
stance which serves to account for the discordant results with 
regard to its production.* 
it deserves remark, that while there runs through the whole 
series of acidifiable bases in relation to their combinations with 
oxygen and hydrogen, a general analogy, there is also some 
deviation, and something with regard to each that is specific. 
Sulphur affords the most perfect example of their agency. It 
forms an acid with hydrogen; it forms another with oxygen ; 
and a third, still more powerful, from the joint action of oxygen’ 
and hydrogen. Carbon forms an acid with oxygen; it also 
forms a series of acids of greater strength with oxygen and 
hydrogen; it acquires no acidity, however, from hydrogen 
alone ; and with an inferior proportion of oxygen it forms an 
oxide. Phosphorus bears a strict analogy to sulphur, except 
that its combination with hydrogen does not give rise to acidity, 
a circumstance in which it resembles carbon. Nitrogen is peculiar 
in forming two oxides with different definite proportions of 
oxygen ; it is doubtfulif it forms a free acid with oxygen alone; 
* The difficulty of entirely excluding water and hydrogen from the constituents 
of this gas is sufficiently apparent, And the fact that it cannot be formed from 
them by the action of the electric spark, but only by the continued action of solar 
light, is favourable to the above opinion. The conversion of carbonic oxide into 
carbonic acid by the joint action of oxymuriatie gas and hydrogen, an experiment 
which I performed when the new hypothesis with regard to the nature of chlorine 
was brought forward, and which was attempted to be invalidated by some singular 
controversial methods, I consider as depending probably on the same principle. 
oY 
