VOL. XC.] PHILOSOPHICAL TRANSACTIONS. 6l5 



sumption that it is an oxygenated substance; as those bodies promise to be the 

 most successful agents that possess a strong affinity for oxygen. Now, of all 

 known bodies, charcoal most strongly attracts oxygen ; I have therefore repeatedly 

 attempted the destruction of this acid, by passing it over red-hot charcoal. But 

 in a series of experiments, which I made some time since, with this view, in con- 

 junction with Mr. Rupp, we soon found reason to be dissatisfied with the difficulty 

 and uncertainty of this process. An immense production of hydrogenous gas 

 took place; but it was not easy to determine whether it had its origin from real 

 acid, or from water. Our experiments however, though insufficient to furnish de- 

 cisive proof, induced us to believe that it had the latter origin. 



It next occurred to me, that the comparative affinities of the muriatic radical, 

 whatever it may be, and of charcoal, for oxygen, would be elegantly and satis- 

 factorily ascertained, by electrifying together the carbonated hydrogen and muriatic 

 gases. If the muriatic acid be capable of decomposition by carbon, it might be 

 expected to be destroyed by this process ; and the exact quantity of acid decomposed, 

 and the nature and quantity of the products would thus be easily determined. I 

 electrified therefore, the muriatic acid and carbonated hydrogen gases, with the most 

 scrupulous attention to the phenomena and results. That the electric fluid might 

 not be misapplied, in decomposing the water of the carbonated hydrogen gas, it 

 was kept more than a week, before use, over quick-lime, introduced to it while 

 yet hot. 



Exper. 10. Of this carbonated hydrogenous gas, 186 measures were expanded, 

 by 130 shocks, to 21 1 ; that is, the gas was increased about \ its bulk. 



Exper. 11. Of the same gas, 84 measures were mixed with 116 of muriatic 

 acid gas, dried by muriate of lime. By 120 shocks, the mixture was a little 

 dilated. After the admission of a drop or two of water, there remained Ql measures; 

 i. e. the addition of permanent gas was 7 measures, or about as much as might 

 have been expected from the muriatic gas alone. 



Exper. 12. Eighty-three measures of dry carbonated hydrogenous gas, with 89 

 of muriatic acid gas, received 200 shocks. The permanent residue, after the ad- 

 mission of water, was 101 measures: the addition therefore amounted to 18. Of 

 the added 18, 6 may be accounted for by the decomposition of the water of the 

 muriatic gas, and 10 by that of the carbonated hydrogenous gas. There remain 

 therefore only 2 measures that can be supposed to be produced from the muriatic 

 acid gas; a quantity too small to afford grounds for supposing them to arise from 

 decomposed acid. 



Exper. 13. Dry carbonated hydrogenous gas 132 measures, 



mixed with dry muriatic gas 108 



making 240 



by 200 shocks, expanded to 208. 



Part of this gas was then transferred to another tube, and the proportion of per- 

 manent gas ascertained. Through the remainder, 150 additional shocks were 



