57^ On the Decompofition of Muriatic Acid. 



is probably true, and the experiments prove that the cle£tric matter at leaft is incapable of 

 decompofing muiiatic acid. But though no progrefs may have been made towards the de- 

 compofition of the acid by thefc firft experiments, they are yet far from being ufelefs, 

 Cnce we are now fupplied with the means of obtaining the muriatic acid pcrfeftly free 

 from water, namely, that portion which, after repeated eleftrifation, remains unaltered. 

 I have no further remark to make on the firft feries of experiments, except that there ap- 

 pears to be fome obfcurity in the 5th, in which 143 meafures of common air, and 1 16 of 

 muriatic acid gas, were :ele6lrifed, and by 30 fliocks reduced to iii. " The remainder 

 *' confifted of muriatic acid and azote gafes, with a fmall proportion of oxygenous gas." 

 What, then, became of the hydrogen gas ? 



The fecond feries of experiments was to afcertain the effeft produced by eleftrifying the 

 muriatic acid gas with inflammable fubftances. Mr. Henry previoufly obferves, that he 

 has attempted the decompofition of this acid by pafling it over red hot charcoal. " An 

 " immenfe produdlion of hydrogenous gas took place, but it was not eafy to determine 

 " whether it had its origin from real acid or from water." I cannot help being fur- 

 prifed that Mr. Henry (hoUld not have decided this point by pafling muriatic acid gas en- 

 tirely freed from water by eleftrifation, over red hot charcoal, as this was fo obvious a 

 method of afcertaining whether charcoal be capable of decompofing muriatic acid. 



In the I2th experiment, Mr. Henry pafled 200 ftiocks through a mixture of 83 meafures 

 of carbonated hydrogen gas, and 89 of muriatic acid gas. The permanent refidue, after 

 the admifiion of water, was loi meafures; the addition, therefore, amounted to 18; of 

 thefe 6 may be accounted for by the decompofition of the water of the muriatic acid gas^ 

 and 10 by that of the carbonated hydrogen gas. There. remain, therefore, only 2 meafures 

 that can be fuppofed to be produced from the muriatic acid gas ; a quantity, Mr. Henry 

 obferves, too fmall to aiford grounds for fuppofing them to arife from decompofed acid. 

 Now, in the decompofition of the water of the carbonated hydrogen gas by the carbon, the 

 oxygen of the water unites with the carbon, and forms carbonic acid, which being foluble 

 in water, would on the admifiion of water, after the eleftrifation, wholly, or in part, dif- 

 appear ; fo that the increafe is greater than 2, by all the carbonic acid diflblved in the water. 

 It is not, therefore, improbable that the muriatic acid gas was in part decompofed in this 

 experiment, and that the reafon why more of it was not decompofed is owing to there not 

 having been more charcoal prefent, part of what there was being employed in decompofing 

 the water. Indeed, when it is confidered that the carbon in carbonated hydrogen gas is 

 minute in quantity, and that it has to decompofe the water contained in the two gafes 

 before it can a£t on the muriatic acid gas, it appears that this is not the beft method of 

 afcertaining whether carbon can decompofe muriatic acid. There appears to me no better 

 method than to pafs muriatic acid gas, perfedly freed from water, over red hot charcoal, 

 and to examine whether carbonic acid and liydrogen are produced. 



Obfetvations 



