of certain inflammable gaseous compounds. 3 g 
,4700; one hundred cubical inches weighing 14,2 grains. 
The flame with which this mixture burned was of the same 
colour and intensity as that of common coal gas ; its dilata- 
tion by heat was similar, and it underwent an analogous in- 
crease of bulk when heated witli sulphur. 
The readiness with which carburetted hydrogen is decom- 
posed, when passed through red hot tubes, appears to me to 
offer a solid objection to a mode of purifying coal gas, which 
has been proposed by Mr. G. H. Palmer,* since it would 
deposit carbon, and consequently sustain great loss in illumi- 
nating power. The object in view was probably to get rid 
of the sulphuretted hydrogen ; but neither is this so to be 
attained. In examining coal gas, I have often been struck 
with the formation of sulphurous acid during its combustion ; 
though when passed through solution of acetate of lead, it 
occasioned no blackening, a circumstance which led me to 
suspect the presence of some other sulphureous compound ; 
and I have often thought, in passing the open gas pipes in 
the streets, that I perceived the smell of sulphuret of carbon. 
When sulphurous acid or sulphuretted hydrogen are passed 
with carburetted hydrogen through a red hot tube, a por- 
tion of carburet of sulphur is always formed, and the vapour 
of that highly volatile compound may well exist in the gas 
employed for illumination, which is always hurried through 
the condensers and gasometer. 
8. Most of the above experiments were now repeated 
upon the gas obtained by the decomposition of whale oil ; 
its specific gravity was ,7690 ; so that 100 cubical inches 
weighed rather more than 23 grains. Deducing the compo- 
* Peckston, on the Theory and Practice of Gas-lighting, p. 213. 
