C 401 3 
XVIII. Experiments on carbonated hydrogenous Gas; with a 
View to determine whether Carbon be a simple or a compound 
Substance , By Mr. William Henry. Communicated by Mr . 
Thomas Henry, F. R. S. 
Read June 29, 1797. 
The progress of chemical science depends not only on the 
acquisition of new facts, but on the accurate establishment, 
and just valuation, of those we already possess: for its general 
principles will otherwise be liable to frequent subversions ; and 
the mutability of its doctrines will but ill accord with the unvaried 
order of nature. Impressed with this conviction, I have been in- 
duced to examine a late attempt to withdraw from itsrankamong 
the elementary bodies, one of the most interesting objects of 
chemistry. The inferences respecting the composition of char- 
coal, deduced by Dr. Austin from his experiments on the 
heavy inflammable air,* lead to changes so numerous in our 
explanations of natural phasnomena, that they ought not to 
be admitted without the strictest scrutiny of the reasoning of 
this philosopher, and an attentive repetition of the experi- 
ments themselves. In the former, sources of fallacy may, I 
think, be easily detected ; and in the latter, there is reason to 
suspect that Dr. Austin has been misled by inattention to some 
collateral circumstances. Several chemists, however, of dis- 
tinguished rank have expressed themselves satisfied with the 
* Phil. Trans. Vol. LXXX. p. 51. 
