XVIII. Description of an Apparatus for the Analysis of the Com- 
pound Inflammable Gases by slow Combustion ; with Experi- 
ments on the Gas from Coal , explaining its Application. By 
William Henry, M. D. Vice-Pres. of the Lit. and Phil. 
Society , and Physician to the Infirmary, at Manchester. Com- 
municated by H. Davy, Esq. Sec. R. S. 
Read June 23, 1808. 
m 
1 he aeriform compounds of hydrogen and carbon, which 
were already entitled to accurate investigation, as objects 
of scientific research, have derived an additional claim to 
the attention of the chemist, from their application to an 
important economical purpose, described in a late commu- 
nication to the Royal Society.* Yet there is, perhaps, no 
part of chemistry, the investigation of which is beset with 
greater difficulty, or with more numerous sources of error ; 
insomuch, that the actual state of the science enables us to 
attain scarcely more than approximations to the truth, and 
degrees of probability of greater or less amount. It was 
the object of the experiments, which are described in the fol- 
lowing pages, rather to remove some of the obstacles, which 
present themselves to a successful enquiry into the nature of 
these bodies, than to acquire such facts, as may enable the 
chemical philosopher to decide the controverted question re- 
specting their composition. Results, sufficiently multiplied 
* See Mr. Murdoch’s paper, p. 124. 
