“ ON MURIATIC ACID Gas, &c. 293 
tains apparently even less water than the salt formed by the 
combination of the two gases. Still, objections entitled to less 
consideration than this one, had been maintained in the course 
of this controversy. I therefore thought it right to repeat the 
experiment, with the necessary precaution to obviate it, and to 
observe the actual result. 
Thirty grains of muriate of ammonia, formed from the com- 
bination of muriatic acid and ammoniacal gases, were put into 
a glass tube with a slight curvature. Two hundred grains of 
clean and dry iron filings were placed over it. The tube was 
put'in a case of iron with sand, and placed across a small fur- 
nace, so that the middle part, where the iron filings were, was 
at'a red heat, the extremity, terminating in the mercurial 
trough. The salt, from the heat reaching the closed extremi- 
ty of the tube, soon passed in vapour through the ignited iron. 
Gas issued from the extremity, and moisture appeared in the 
cold part of the tube. A large quantity of gas was collected, 
which had the odour quite strong of muriatic acid, and was in 
part condensed by water; the residue burned with the flame of 
hydrogen. The tube, for several inches, was studded with glo- 
bules of water, and was bedimmed with vapour farther. I did 
not prosecute the experiment, so as to ascertain the weight of 
water produced, as' I had other experiments in view, which I 
conceived might afford more conclusive results. But it proves 
the point. it was designed to establish, that water is obtained’ 
from the salt formed by the combination of the gases, as well 
as from the common sal ammoniac. 
My: attention having been thus recalled to the subject, I have 
again executed the experiment in its original and simplest: 
form,—that of obtaining water from the salt by heat alone; 
and to this I was led more particularly, as it had occurred to 
me, that a more perfect abstraction of its water might be ef- 
fected, 
