EXPSatMENTS ON MURIATIC ACID OA«. 1^7 



ir'tekled down ; the heat being applied gently, that the salt 



itself might not be volatilized, thert was no sensible conden- 



•ation of humidity on the sides of the receiver, or in the 



tube inserted into it. When the farther condensation of 



fiaoisture appeared to have cessed, the lamp waa withdrawn, 



the retort was cut, and the residual salt removed ; a little of 



it, which had been volatilized, and formed a thin film on the 



upper part of the retort, being collected, and added to the 



other portion. The salt had lost in weight 1*3 gr. — a loss The salt lui 



obviously to be ascribed to llie expulsion of water, and the ^**** weight, 



<|uantity candensed in the neck of the retort appeared fully water. 



«qual to this. This is the smallest portion too, that was 



obtained in frequent repetitions of the ei^periment, and ia 



conae of these the quantity was equal to 1'5 gr. ; a difference 



depending probably on the temperature applied. 100 cubic To the amount 



inches of muriatic acid gas weighing 30 grains, 30 cubic ^^^^'c^'n^^f 

 . , . , , , • ^ T. ,« . the weight of 



inches weigh 11*7 gr.; and this anording 1*3 ot water gi¥€s the mirriatic 



the proportien of y of its weight. "'<1* 



It could not be presumed however, that in this experi"* This propaMy 

 ment the whole water of the compound salt was disengaged, ofihe^wer 

 In every case of the combination of an acid with any base, present. 

 |)art of the water of the acid enters with it into the combin* 

 atkyn, at least when the product is a soluble salt, and is not 

 easily entirely abstracted. There is no reagon to suppose, 

 that this should not be the case ia the combination of muri- 

 atic acid and ammonia; and there must be even a greater 

 difficulty in expelling this water from an animoniacal salt 

 by heat, than from other salts, on account of its volatility. 

 There is another difficulty in the present case; we cannot 

 introduce the affinity of any other substance to the acid, 

 wTiich, combining with it, might allow a portion of the wa- 

 ter to be disengaged; for we can employ no substance with 

 this view, but one which is oxidated, and which would there- 

 fore introduce a source of ambiguity, as it might be suppos- 

 ed, on Mr. Davy's hypothesis, to form water by its action on 

 the acid itself. 



The most direct method of discovering any farther portion Most dinct 

 of water in the salt, free from this ambisruitv, appeared to ^^thodof 

 1. ' .. ju • -11, p proving thii, 



b^ to expose it to a red heat in mixture with charcoal; for, 



although the whole quantity could not be expected to be 



-abstracted 



