Exptfimentt te decompo/e the Muriatic Acid. 



tie 



Of this gas, 307 meafures were reduced, by 20 fliocks, to 227, or were contracted nearly 

 one-fourth. Gas from the fame materials, after they had continued working for fomc 

 hours, was diminiftied, by fimilar treatmetit, only about a twelfth. Thefe efFefts, there- 

 fore, it feemed probable, depended in fome meafure on the prefence of moifture ; and I 

 accordingly found, that muriatic acid gas, after more than a week's expofure to muriate of 

 lime, brought into contadl with it immediately after cooling from a ftate of fufion, was 

 fcarcely diminiflied at all ; and that the depofit, though it ftill occurred, was lefs copious in 

 quantity. This depofit was not, like corrofive fubliraate, foluble in water ; but had every 

 property of the lefs faturated fait, calomeL 



The mercury by which the muriatic acid was confined, was therefore evidently oxidated j. 

 and, to the combination of a part of the gas with the oxide thus produced, the diminution 

 of bulk was doubtlefs to be afcribed. But it was uncertain from whence this oxygen waa 

 derived. It might either refult fro^^ the decompofition of the acid gas, or of the water 

 chemically combined with it. The following experiments were therefore made, to de- 

 termine this point. 



Experiment I. Through 1457 meafures of muriatic acid gas, 300 eleftrical fliocks were 

 pafled. There remained, after the admiffion of water, lOO meafures of permanent gas, (or 

 not quite 7 from each hundred of the original gas,) which, on trial, appeared to be purely 

 hydrogenous. 



Exper. 2. Of the gas, dried by muTiate of lime, 176 meafures received 120 fliocks. 

 The reGduc of hydrogenous gas amounted to 11 meafures, or rather more than 

 6 per cent, 



Thefe experiments, and other fimilar ones, made on comparative portions of muriatic 

 acid gas, in its recent ftate, and after expofure to muriate of lime, convinced me that it was 

 impoflible, by this method, v/holly to deprive the muriatic gas of water. The recent gas, 

 however, when electrified in fmaller quantity than in experiment i, gave a larger propor- 

 tion of hydrogenous gas; which fliews, that fome portion of its moifture was removed, 

 by expofure to muriate of lime. In order, if poflible, to procure the gas perfe£lly dry, 

 another mode of preparing it was reforted to. Alum and common fait were firft well 

 calcined, feparately, to expel their water of eryftallization, and, being then mixed, were 

 diftilled together in an earthern retort. The gas proceeding from thefe materials, was re- 

 ceived over dry mercury ; but, though only the Ijft portion that came over was referved 

 for experiment, it ftill, after the ufual eleCtrization, afforded a produ£l of hydro- 

 genous gas. 



In the Gourfe of the preceding experiments, I obferved that the diminution of the 

 muriatic acid gas ftopped always at a certain point, beyond which it could not be carried 

 by continuing the fliocks. Gas alfo, which had been thus treated, when transferred to 

 another tube, and again eleftrified, did not exhibit any further depofit. It became in- 

 terefting, therefore, to know, whether the produdion of hydrogenous gas had a fimHax 



£e 2. limitatiotr^ 



