292 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 Ure 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 Ure'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 f, 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 



« Nicholson's Journal, vol. xxxi. p. 129. f Id. vol. xxxiv. p. 274* 



