2 Mr. Davy's Researches on the 
from oxymuriatic acid, or from dry muriates, unless water or 
its elements be present. 
In the second volume of the Memoires d’Arcueil, M. M. 
Gay Lussac and Thenard have detailed an extensive series of 
facts upon muriatic acid, and oxymuriatic acid. Some of their 
experiments are similar to those I have detailed in the paper 
just referred to ; others are peculiarly their own, and of a very 
curious kind: their general conclusion is, that muriatic acid gas 
contains about one quarter of its weight of water ; and that 
oxymuriatic acid is not decomposable by any substances but 
hydrogene, or such as can form triple combinations with it. 
One of the most singular facts that I have observed on this 
subject, and which I have before referred to, is, that charcoal, 
even when ignited to whiteness in oxymuriatic or muriatic 
acid gases, by the Voltaic battery, effects no change in them ; 
if it has been previously freed from hydrogene and moisture 
by intense ignition in vacuo. 
This experiment, which I have several times repeated, led 
me to doubt of the existence of oxygene in that substance, 
which has been supposed to contain it above all others in a 
loose and active state ; and to make a more rigorous investi- 
gation than had been hitherto attempted for its detection. 
If oxymuriatic acid gas be introduced into a vessel exhausted 
of air, containing tin ; and the tin be gently heated, and the 
gas in sufficient quantity, the tin and the gas disappear, 
and a limpid fluid, precisely the same as Libavius’s liquor is 
formed ; — it occured to me, that if this substance is a combina- 
tion of muriatic acid and oxide of tin, oxide of tin ought to be 
separated from it by means of ammonia. I admitted ammoniacal 
gas over mercury to a small quantity of the liquor of Libavius ; 
