180 Dr. Henri/ on the Aeriform Compounds [Sept. 



respects agreeing nearly with olefiant gas ; but when mingled 

 with more than the requisite proportion of chlorine, it was not, 

 as olefiant gas would have been, entirely condensed, but suf- 

 fered a diminution of only four-tenths of its bulk, the remaining 

 six-tenths, after being freed from the redundant chlorine, agree- 

 ing in its properties with carburetted hydrogen. For example, 

 10 volumes of this gas (containing four of gas condensible by 

 chlorine and 6 of carburetted hydrogen) consumed 30 volumes 

 of oxygen, and gave 18 of carbonic acid. But of the oxygen, 

 12 volumes are due to the 6 of carburetted hydrogen, leaving 

 18 volumes for the combustion of the four volumes of gas con- 

 densible by chlorine, which is in the proportion of 44- to 1. Of 

 the 18 volumes of carbonic acid, also, 6 may be traced to the 

 combustion of the carburetted hydrogen, leaving 12 volumes as 

 the product of four of the condensible gas, or in the proportion 

 of 3 to 1. The portion of gas, condensed by the action of chlo- 

 rine, presents, therefore, decided differences from olefiant gas, 

 in requiring not three only, but 4i volumes of oxygen for com- 

 bustion, and in affording 3, instead of 2 volumes of carbonic 

 acid. Nearly the same relation of the oxygen consumed, and 

 carbonic acid produced, to that part of the gases from coal and 

 oil which is condensible by chlorine, existed also not only in 

 other experiments of Mr. Dalton, but in all those which I have 

 myself made. The proportions I have found to vary in different 

 cases from 4-±- to 5 volumes of oxygen, and from 2\ to 3 volumes 

 of carbonic acid for each volume of the condensible gas. 



On comparing also the specific gravity of the gases from coal 

 and oil, as ascertained by experiment, with that which ought to 

 result from mixtures of the residue left by chlorine, with such a 

 proportion of olefiant gas as is deducible from analysis, I have 

 invariably found that the real specific gravity has considerably 

 exceeded the estimated. For instance, the London oil gas was 

 composed of 38 volumes of a gas condensible by chlorine, and 

 62 volumes of mixed gases not characterized by that property, 

 and having the specific gravity •606. But 62 volumes of gas, 

 of specific gravity "606, mixed with 38 volumes of olefiant gas, 

 of specific gravity *970, should give a mixture of the specific 

 gravity '754, instead of '906, which was the actual specific gra- 

 vity of the entire oil gas. It will be found on calculation that 

 the 38 volumes of gas, in order to make up the real specific 

 gravity of the oil gas, must have had the specific gravity of 1*4 

 very nearly. This is the highest number that is deducible from 

 my experiments for the specific gravity of that portion of oil gas 

 or coal gas, which is condensed by the action of chlorine. In 

 other instances, it varied from that number down to 1'2, but in 

 every case its weight surpassed that of common air. 



It is evident from these facts that the aeriform ingredient of 

 oil gas and coal gas, which is reducible to a liquid form by 

 chlorine, is not identical with the olefiant gas obtained by the 



