1821.] Aeriform Compounds of Charcoal and Hydrogen. 167 



Article II. 



On the Aeriform Compounds of Charcoal and Hydrogen; with 

 an Account of some additional Experiments on the Gases from 

 Oil and from Coal. By William Henry, MD. FRS * 



The experiments on the aeriform compounds of charcoal and 

 hydrogen, described in the following pages, are supplementary 

 to a Memoir on the same class of bodies, which the Royal 

 Society did me the honour to insert in their Transactions for 

 1808, as well as to other papers on the same subject, which 

 have been published in Mr. Nicholson's Journal, and in the 

 Memoirs of the Manchester Society. Of these essays, I beg 

 leave to offer a very brief recapitulation, with the view merely of 

 connecting them with what is to follow. 



In the first of these essays (Nicholson's Journal, 8vo. June, 

 1805), I detailed a series of experiments on the gases obtained 

 by the destructive distillation of wood, peat, pit-coal, oil, wax, 

 &c. from which it appeared that the fitness of those pases fox- 

 artificial illumination was greater, as they required for combus- 

 tion a greater proportional volume of oxygen ; and that the 

 gases generated from different inflammable bodies, or from the 

 game inflammable substance under different circumstances, are 

 not so many distinct species, which, under such a view of the 

 subject, would be almost infinite in number, but are mixtures of 

 a few well known gases, chiefly of carburetted hydrogen with, 

 variable proportions of olefiant, simple hydrogen, sulphuretted 

 hydrogen, carbonic acid, carbonic oxide, and azotic gases ; and 

 that the elastic fluids obtained from coal, oil, &c. have probably, in 

 addition to these, an inflammable vapour diffused through them 

 when recent, which is not removed by passing them through 

 water.f In the same paper, I explained certain anomalies that 

 appear in the experiments of the late Mr. Cruickshank, o£ 

 Woolwich, which are not at all chargeable as errors upon that 

 excellent chemist, and could only be elucidated by further inves- 

 tigation of the gases to which they relate. Of his labours it 

 would be unjust, indeed, to speak in any terms but those of 

 approbation, for they may fairly be considered as the foundation 

 of most that is now known respecting this species of aeriform 

 bodies. To Mr. Dalton, also, we are indebted for an accurate 

 acquaintance with carburetted hydrogen gas, and for much 

 information that is valuable in assisting us to judge of the com- 

 position of mixed combustible gases, by the phenomena and 

 results of firing them with oxygen.^ 



* From the Philosophical Transactions, 1821. 



t Nicholson's Journal, 8vo. xi. 72. 



% New System of Chemical Philosophy, passim. 



