of charcoal and hydrogen. 159 
charcoal in different proportions from those composing any 
known compound of those elements ; — or it may be merely 
the vapour of a highly volatile oil, mingled in various pro- 
portions with olefiant gas, carburetted hydrogen, and the 
other combustible gases. Of these two opinions, Mr. Dal- 
ton is inclined to the first, considering 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 af- 
fected by chlorine precisely as if it were mixed with a small 
proportion of olefiant 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 essential oil. The 
smell also of the liquid which is condensed on the inner sur- 
face 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 odour 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 farther investigation ; but having devoted to the enquiry all 
the leisure which I am now able to command, I must remain 
satisfied at present with such conclusions as are safely dedu- 
cible from the foregoing investigation. These may be briefly 
recapitulated as follows : 
1. That carburetted hydrogen gas must still be considered 
