Analysis of the compound inflammable Gases . 293 
Of this gas 100 cubic inches, at a mean of the barometer and 
thermometer, were equal to 30 troy grains ; hence its specific 
gravity was 967. 
In the receiver 0 0, were contained of this gas 6 . 3 cub. in. 
Residue .... 2 
Gas consumed - - 4.3 
In the receiver b, were 43.4 inches of oxygen gas. After 
the combustion, there remained 38.2 cubic inches of mixed 
gases, of which 8.6 were carbonic acid. None of the inflam- 
able gas, which passed through the bent tube, had escaped 
being burned, for the quantity of gas in b, not absorbable by 
sulphuret of lime, so far from having been increased, was 
found to have sustained a trifling diminution. The oxygen 
gas, which was consumed, amounted to 13.8 cubic inches. 
Reducing these results to centesimal proportion, 100 cubic 
inches of this gas would give 200 of carbonic acid, and absorb 
325 of oxygen gas. This experiment agrees with Mr. Dal- 
ton's, as to the proportion of carbonic acid from the combus- 
tion of olefiant gas, but assigns a larger consumption of 
oxygen. It may be observed, however, that the specific 
gravity of the gas, which I employed, exceeded a little the 
statement of the Dutch chemists, who found its specific gravity 
to be 909, common air being 1000. 
Having satisfied myself, by repeated experiments, of the 
accuracy of the results which may be thus obtained, I pro- 
ceeded to the combustion of the gases from a variety of veget- 
able substances, and especially from those which it seemed 
probable might become economical sources of light. In the. 
present memoir, I shall describe those only, which were made 
