992 EXPERIMENTS AND OBSERVATIONS 
water, is evident from this, that the water appeared at the mo- 
ment the salt began to pass in vapour, and at a temperature 
far below that at which the charcoal had ceased to afford any gas. 
In another variation of the experiment, muriate of ammonia 
was passed in vapour, through an ignited porcelain-tube alone. 
Water was obtained in larger quantity than when the salt had 
been exposed to a heat short of its volatilization ; and even the 
salt which had yielded water by that operation, afforded an ad- 
ditional quantity in this mode,—a proof of the more perfect se- 
paration of the water by the effect of a higher temperature *. 
By all these results, then, 1 consider the existence of water 
in muriate of ammonia, and of course in muriatic acid gas, as 
demonstrated. . 
Dr Une has lately laid before the Society the result of ano- 
ther mode of conducting the experiment,—that of subliming 
the muriate of ammonia\over some of the metals, at the tem- 
perature of ignition. Water is thus stated to be obtained in 
considerable quantity, with a production of hydrogen gas. 
No objection appeared to Dr Urr’s experiment, except, per- 
haps, that the salt operated on, was not that formed by the di- 
rect combination of its constituent gases, but the common sal 
ammoniac, in which water might be supposed to exist, either 
as an essential, or an adventitious ingredient, as it is abundant- 
ly supplied to it in the processes by which it is formed. I had 
found, indeed, in some of my former experiments}, that sal 
ammoniac yields no water when exposed to a heat sufficient to 
sublime it, but affords it only when exposed to a red heat by 
transmission of its vapour through an ignited tube,—that, 
_ therefore, (owing no doubt to its previous sublimation,) it con- 
- tains 
* Nicuorson’s Journal, vol. xxxi. p. 129. + Id, vol. xxxiv. p. 274, 
