24 Mr. Brande on the composition and analysis 
and that the quantity of oxygen consumed 
by the olefiant gas will be = 7800 cubical inches, 
by the oil gas - = 11578. 
by the coal gas - =21516. 
Olefiant gas cannot of course be employed for any economical 
purposes, and is only here adverted to for the sake of com- 
parison. The relation of the quantity of oil gas to that of 
coal gas, furnishes a datum that may be practically useful, 
especially as indicating the relative sizes of gasometers re- 
quired for the supply of establishments. It may, I think, be 
stated with sufficient accuracy for practical purposes, that a 
gasometer containing 1000 cubical feet of oil gas, is adequate 
to furnish the same quantity of light as one of 3000 cubical 
feet of coal gas, provided due attention be paid to the con- 
struction of the burners, and to the distribution of the lights. 
7. For the ordinary purposes of illumination by oil gas, I 
consider ten hole Argand burners, each consuming about a 
cubical foot and a half per hour, and giving the light of seven 
wax candles, or nearly two oil Argands, as the most economical 
and generally useful. Single jet burners, or those in which 
the flames do not coalesce, consume, as has been above shown, 
a very much larger quantity of gas for the production of an 
equal quantity of light ; and for the same reason, Argand 
burners, in which the flames do not coalesce, consume more 
gas for an equal production of light, than those in which the 
apertures are more numerous, but sufficiently near each other 
to allow of the union of the separate flames. 
8. To ascertain the relative heating powers of the flames 
of olefiant, oil, and coal gases, I employed the twelve hole 
Argand burners mentioned above, and placed over each, as 
near to the lamp glass as was consistent with a clear flame, a 
