* 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, 



