170 Experiments on the Gas from Coal. 



2dlv. It is inconsistent with experience, that two bodies which, 

 like hydrogen and charcoal, unite by an energetic affinity, should 

 combine in all possil)le proportions. On the contrary, it is to be 

 expected from analogv in general, and from that of the com- 

 pounds of charcoal and oxvgen in particular, that hydrogen and 

 charcoal unite in few proj)ortions only, and in such a manner 

 that these proportions are multiples or divisors of each other by 

 some entire number. 



3dly. All the phaenoinena may be satisfactorily explained by 

 supposing the gas from coal, and from other inflammable sub- 

 stances, to b^ mixtures of this kind. For example, referring to 

 the one hour's gas in the first table, we shall find that it contains, 

 in 100 measures, IS of olefiant gas, which require for combus- 

 tion 54 measures of oxvgen, and afford 36 of carbonic acid. The 

 same gas contains also 77| measures of another inflammable gas, 

 in the combustion of which 210 — 54=156 measures of oxygen 

 have been spent, and whichhave afforded 112 — 36 = 76 mea- 

 sures of carbonic acid. This is as near an approach as can be 

 expected to the properties of carburetted hydrogen, the 77| 

 measures having consumed very nearly twice their bulk of oxy- 

 gen, and given an equal volume of carbonic acid. We may, there- 

 fore, consider the early products of the gas from cannel as a mix- 

 ture of about one volume of olefiant gas and four volumes of car- 

 buretted hvdrogen *. 



The early product of gas from Clifton coal does not admit of 

 being thus theoretically resolved into a mixture of olefiant and 

 carburetted hydrogen gases only. For after deducting from the 

 oxygen consumed (164 measures) that spent in saturating the 

 olefiant gas (10x3 = 30) we have onlv 134 measures of oxvgen 

 left for the combustion of 90 measures of inflammable gas. These 

 90 measures, it appears, afford 91 — 20 = 71 measures of car- 

 bonic acid. This portion of the gas does not, therefore, answer 

 to the characters of carburetted hydrogen, since it neither gives 

 an equal volume of carbonic acid, nor consumes a double volume 

 of oxygen. In this case and a variety of similar ones, we can 

 only at present explain the phaenomena, by comparing them with 

 hypothetical mixtures of tb.e different known gases. As an ex- 

 ample, I shall describe the particulars of the combustion of the 

 first product of Clifton coal, and endeavour to explain the results 

 in the manner which has been suggested. 



• I am perfectly aware of the importance of taking the specific gravity of 

 mixed gases, as one datum for determining their proportion in any mixture; 

 but I was prevented from ascei-tuining it in these experiments by the state 

 of the necessary apparatus, which was found, from long disuse, to have 

 become unfit for the purpose. So far as respects the practical objects of 

 this paper, the omission is of no consequence. 



Measures 



