MEMOIR OF THE LATE DR. HENRY. 119 
portions, which the gases, left after the action 
of chlorine on oil and coal gas, bear to each 
other. For this purpose he skilfully availed 
himself of the property, which had been recently 
discovered by Dobereiner in finely divided pla- 
tina, of determining gaseous combination. Hay- 
ing ascertained that carbonic oxide with oxygen 
is rapidly converted into carbonic acid, in pre- 
sence of platina at a temperature of 340° 
Fahrenheit, while carburetted hydrogen is 
wholly unchanged, till the heat considerably 
exceeds that of boiling mercury, Dr. Henry 
exposed a mixture of carbonic oxide, hydrogen, 
and carburetted hydrogen with oxygen, into 
which platina had been admitted, to the tem- 
perature of 340°. The carbonic oxide and 
hydrogen were converted into carbonic acid 
and water,—and their relative proportions easi- 
ly determined. The residuary carburetted hy- 
drogen was then detonated with oxygen ina 
volta eudiometer. The numbers thus obtained 
corresponded precisely with the quantities of 
the gases that had been mingled together. In 
further trial of this new mode of operating, it 
was applied to the analysis of a mixture of the 
same gases, but in unknown proportions, which 
constitutes an inferior quality of coal gas. The 
specific gravity of this gas, derived from the 
