222 PHILOSOPHICAL TRANSACTIONS. [ANNO 1797. 



piously diffused through them. If the evolved hydrogen proceeded from the 

 decomposition of the former of these 2 substances, it is evident that a certain 

 volume of the carbonated hydrogenous gas must yield, after electrization, on com- 

 bustion with oxygen, less carbonic acid than an equal volume of non-electrified 

 gas; or, in other words, the inflammation of 20 measures of carbonated hydrogen, 

 expanded by electricity from 10, should not afford so much carbonic acid as 10 

 measures of the unelectrified. 



From the fact which has been before stated, respecting the increased consump- 

 tion of oxygen by the electrified air, it follows, that in determining the quantity 

 of its carbon by combustion, such an addition of oxygen should be made, to that 

 necessary for the saturation of the gas before exposure to the electric shock, as will 

 completely saturate the evolved hydrogen. For if this caution be not observed, 

 we may reasonably suspect that the product of carbonic acid is diminished, only 

 because a part of the heavy inflammable air has escaped combustion. It might 

 indeed be supposed, that in consequence of the superior affinity of carbon for 

 oxygen, the whole of the former substance, contained in the dense inflammable 

 gas, would be saturated, and changed into carbonic acid, before the attraction of 

 hydrogen for oxygen could operate in the production of water. But I have found 

 that the residue, after inflaming the carbonated hydrogenous gaz with a deficiency 

 of oxygen, and removing the carbonic acid, is not simply hydrogenous, but car- 

 bonated hydrogenous gas. 



In the 2d, 5th, and 6th of Dr. Austin's experiments, in which the quantity of 

 carbon, in the electrified gas, was examined by deflagrating it with oxygen, the 

 combustion was incomplete, because a sufficiency of oxygen was not employed; 

 and Dr. Austin himself was aware that, in each of them, " a small quantity of 

 heavy inflammable air might escape unaltered." It is observable also, that the 

 product of carbonic acid, from the electrified gas, increased in proportion as the 

 combustion was more perfect. We may infer therefore, that if it had been com- 

 plete, there would have been no deficiency of this acid gas, and consequently no 

 indication of a decomposition of charcoal. A strong objection however is appli- 

 cable to these, as well as to most of Dr. Austin's experiments, that the residues 

 were not examined with sufficient attention. In one instance we are told, that the 

 remaining gas was inflammable, and in another, that it supported combustion like 

 vital air. I need hardly remark, that a satisfactory analysis cannot be attained of 

 any substance, without the most scrupulous regard, not only to the qualities, but 

 to the precise quantities of the products of our operators. 



To the 8th and 9th experiments, the objection may be urged with additional 

 weight, which has been brought against the preceding ones, that the quantity of 

 oxygen, instead of being duly increased in the combustion of the electrified gas, 

 was, on the contrary, diminished. Thus, in the 8th experiment, 2.83 measures 

 of carbonated hydrogen were inflamed with 4.58 measures of oxygenous gas; but 

 in the 9th, though the 2.83 measures were dilated to 5.1 6, and had therefore 



