of Charcoal and Hydrogen. ; 173 
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 gravity of 
the entire oil gas.” It will be found on calculation that the 58 
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 experi- 
ments for the specific gravity of that portion of oil gas, or coal 
gas, which is condensed by the action of chlorine. In other in- 
stances, 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 aériform ingredient of 
oil gas and coal gas, which is reducible to a liquid form by chlo- 
rine, is not identical with the olefiant gas obtained by the 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 sué generis, hitherto un- 
known, and constituted of hydrogen and charcoal in different pro- 
portions from those composing any known compound of those 
elements ;—or it may be merely the vapour of a highly volatile 
oil, mingled in various proportions with olefiant gas, carburetted 
hydrogen, and the other combustible gases. Of these two opi- 
nions, Mr. Dalton is inclined to the first, considering it as sup- 
ported 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 con- 
tact with fluid naphtha, acquires the property of being affected 
by chlorine precisely as if it were mixed with a smnall proportion 
of olefiant gas; and I am informed by Dr. Hope, thatoil 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 surface of a glass receiver 
in which oil gas or coal gas has been mixed with chlorine, de- 
notes the presence of chloric ether, evidently however mingled 
with the odour of some other fluid, which seems to me to hear 
most resemblance to that of spirit of turpentine. This part of 
the subject is well worthy of further investigation; but having 
deyoted to the inquiry all the leisure-which [ am now able tu 
command, I must remain satisfied at present with such conelu- 
sions 
