38 Dr. Henry's Experiments on the Gas from Coal. [Jan. 



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

 have been spent, and which have 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 vei-y nearly twice their bulk of 

 oxygen, and given an equal volume of carbonic acid. We may, 

 therefore, consider the early products of the gas from cannel as a 

 mixture of about one volume of olefiant gas and four volumes of 

 carburetted hydrogen.* 



The early product of gas from Chfton 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 (10 x 3 = 30) we have only 134 measures of oxygen 

 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 oxyo-en. In this case and a variety of similar ones, we can 

 only at present explain the phenomena, by comparing them with 

 hypothetical mixtures of the different known gases. As an 

 ■example, 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. 



Measures of the gas 11 



Mixed with oxygen 39 = 37 pure oxygen + 2 azote. 



Total 50 



Volume after firing 31 



Ditto after washing by potash 21 = 19 oxygen + 2 azote. 



18 oxygen consumed. 



In this case, the diminution by firing is 19 measures ; that by 

 potash, which denotes the carbonic acid, 10 measures ; and the 

 gases consumed are 11 + 18 = 29. Let us examine what mix- 

 ture of gases will account for the appearances. 



M. ofinfl. gas. Take oxygen. Give cnib. acid. Dimin. by firing. 



M olefiant 3-3 2-2 2-2 



7-0 carb. hydr . . 14-0 7'0 14-0 



1-0 carb. oxide. . 0-5 ........ 0-5 I'D 



2-0 hydrogen. .. 1-0 — 3-0 



iTl iTs 9-7 20-2 



» 1 am perfectly aware of the importance of taking (lie specific gravity of 

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

 was prevented from ascertainiog it in these experiments by the state of the neces- 



