1821.] of Charcoal and Hydrogen. 18 J 



action of sulphuric acid on alcohol, but considerably exceeds 

 that gas in specific gravity and combustibility. Two views may 

 be taken of its nature ; for it may either be a gas sni generis, 

 hitherto unknown, and constituted of hydrogen and charcoal in 

 different proportions from those composing any known com- 

 pound of those elements ; — or it may be merely the vapour of a 

 highly volatile oil, mingled in various proportions with defiant 

 gas, carburetted hydrogen, and the other combustible gases. 

 Of these two opinions, Mr. Dalton is inclined to the first, con- 

 sidering it as supported by the fact that oil gas, or coal gas, 

 may be passed through water, without being deprived of the 

 ingredient in question ; and that this anomalous elastic fluid is 

 absorbed by agitation with water, and again expelled by heat or 

 other gases, unchanged as to its chemical properties, as we have 

 both satisfied ourselves by repeated experiments. On the other 

 hand, I have found that hydrogen gas, by remaining several 

 days in narrow tubes in contact with fluid naphtha, acquires the 

 property of being affected by chlorine precisely as if it were 

 mixed with a small proportion of defiant gas; and I am informed 

 by Dr. Hope, that oil gas, when forcibly compressed in Gordon's 

 portable gas lamp, deposits a portion of a highly volatile essen- 

 tial oil. The smell also of the liquid which is condensed on the 

 inner surface of a glass receiver, in which oil gas or coal gas 

 has been mixed with chlorine, denotes the presence of chloric 

 ether, evidently however mingled with the cdour of some other 

 fluid, which seems to me to bear most resemblance to that of 

 spirit of turpentine. This part of the subject is well worthy of 

 further investigation ; but having devoted to the inquiry all the 

 leisure which 1 am now able to command, I must remain satis- 

 fied at present with such conclusions as are safely deducible 

 from the foregoing investigation. These maybe briefly recapi- 

 tulated as follows : 



1. That carburetted hvdros;en eras must still be considered 

 as a distinct species, requiring for the perfect combustion of 

 each volume two volumes of oxygen, and affording one volume 

 of carbonic acid ; and that if olefiant gas be considered as con- 

 stituted of one atom of charcoal united with one atom of hydro- 

 gen, carburetted hydrogen must consist of one atom of charcoal 

 in combination with two atoms of hydrogen. 



2. That there is a marked distinction between the action of 

 chlorine on olefiant gas (which, in certain proportions, is entirely 

 independent of the presence of light, and is attended with the 

 speedy condensation of the two gases into chloric ether), and 

 its relation to hydrogen, carburetted hydrogen, and carbonic 

 oxide gases, on all which it is inefficient, provided light be per- 

 fectly excluded from the mixture. 



3i That since chlorine, under these circumstances, condenses 

 olefiant gas without acting on the other three gases, it may be 



