1816.] respecting the Nature of Oxymuriatic Acid. 278 
guished men as Davy, Gay-Lussac, Vauquelin, &c, to adopt such 
opinions, must appear very strong; while their example must pro- 
duce a great effect upon others. At the same time, I am aware 
that the obstinacy with which many philosophers adhere to old 
opinions is owing to their incapacity of perceiving the force of the 
arguments which are urged against them. ‘The danger, however, of 
having this reproach thrown against myself, will not deter me from 
waging a war, from which, whatever should be the result, science 
must be a considerable gainer, 
——- 
Sir H. Davy found that a piece of charcoal, brought by means of 
the galvanic battery to the most violent heat, was unable to decom- 
pose or alter dry oxymuriatic gas. Hitherto oxymuriatic acid had 
been considered as a loose compound of muriatic acid and oxygen. 
From the preceding experiment, it follows that this opinion is inac- 
curate. Davy now supposed, in consequence of this, that oxymu- 
riatic acid is a simple substance, to which he gave the name of 
chlorine; and in order to demonstrate the truth of this opinion, he 
made oxymuriatic gas to act upon hot salifiable bases. The gas was 
absorbed, anda quantity of oxygen gas disengaged exactly equal to 
that which the salifiable basis contained. Hence he concluded that 
the oxygen did not proceed, as had been hitherto supposed, from 
the oxymuriatic acid gas, but from the salifiable basis itself. The 
impossibility of separating oxygen from oxymuriatic acid, by any 
method hitherto tried, he considered as a proof that the old opinion 
is wrong, and that, according to his own words, ‘* chlorine must 
be regarded, according to a just logic of chemistry, as an elemen- 
tary substance.” (Elem. of Chem. Philos. i. 241.) Davy has since 
that time endeavoured to establish his opinion still more-completely, 
and to confirm it by new proofs: and he now considers it as demon- 
strated that the old opinion is an improbable hypothesis, because it 
cannot be confirmed by experiment. It has not indeed escaped his 
observation that chlorine possesses properties which it would pro- 
bably not have unless it were an oxydized body; but at the same 
time he lays it down (p. 485) that we are not entitled to infer from 
this that chlorine contains muriatic acid. 
As the new opinion, and its apparent superiority over the old, 
depends chiefly upon these facts, | shall examine the degree of force 
which they possess. 
It was expected, when charcoal was heated to redness in oxymu- 
riatic gas, that carbonic oxide and common muriatic acid would 
have been formed. But the muriatic acid gas which we obtain is a 
compound of pure acid and water, just as concentrated sulphuric 
acid is a compound of real acid and water. Hence the reason why 
this expectation cannot be fulfilled ; for the charcoal must either 
convert the oxymuriatic acid to muriatic acid destitute of water, or 
to muriatic radical, But if muriatic acid can exist only in compo- 
