27$ WATBR IN MURIATIC ACID GA8. 



•ir-tigbt by cement, a stop-cock being inserted in one of them 



for the introduction of the gases. 



in which the The vessel having been exhausted, about 27 cubic inches of 



dried mur. ae. . . . , f. , , , , , „ 



and amnion, muriatic acid gas, which had been exposed for two days to dry 



gases were muriate of lime, were combined in it with the requisite quan- 

 Careful exa- *' tv or " ammoniacal gas, which bad been exposed for the same 

 mination of time to dry potash ; and an excess of ammonia was allowed 

 balance dor^ to reraain at tbe end of tne combination. The corks, with their 

 ing full expo- cement, were removed, and clean corks, previously fitted, were 

 showed 1 'noli- instanll y inserted. The vessel was filled with atmospheric 

 crease, but a air, by opening one of the orifices, and introducing a tube at- 

 loss ot weight, t ac h e d to a caoutchouc bottle, the sides of which being pressed 

 together, and then allowed to dilate, drew out the ammoniacal 

 gas : and to secure the change being complete, both corks 

 were removed for a second or two. The apparatus was then 

 placed in a balance, which, loaded with it, turned very sensibly 

 with much less than ^ of a grain. The balance being accu. 

 rately adjusted, the corks were removed from the orifices, and 

 . x placed beneath the vessel, and the progress .of the experiment 

 was observed. At the end of five minutes there was no per- 

 ceptible change, of ten minutes no change, at fifteen minutes 

 there was, if any thing, a loss of weight on the side of the 

 salt, at twenty minutes this loss was apparent, and amounted 

 to about ^l of a grain, at twenty-five and at thirty minutes it 

 remained the same. Though from the form of the vessel, and 

 the size of the apertures, the air had the freest access to the 

 salt which encrusted the interior ; yet, to leave no doubt, the 

 internal air was changed repeatedly by means of the caoutchouc 

 bottle. At forty minutes there was again the appearance of 

 loss of weight in the salt, at fifty minutes this amounted to 

 something less than ± Q of a grain, in addition to the former 

 loss. The air within the vessel was again repeatedly changed, 

 both by means of the caoutchouc bottle, and by propelling the 

 external air through it by the motion of the hand, and by the 

 bottle, held at a distance and slowly compressed j but for half 

 an hour longer there was no perceptible variation of weight*. 



This 



* In a preliminary experiment which I had performed, and in which 

 the sail was freely exposed to the air for three days, the loss of weight 



