Experiments on the Gas from Coal. 171 



Measures of the gas 11 



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



Total ^ 



Volume after firing 31 



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



18 oxygen consumed. 

 In this case, the diminution by firing is"l9 measures; that by 

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

 gases consumed are 1 1 + 18 = 29. Let us examine what mix- 

 ture of gases will account for the appearances, 



M. of infl. Gas. Take Oxyg. Give Carb. Acid. Dimin. by firing. 

 1-1 Olefiant .. 3.3 .. .. 2-2 ., .. 2-2 

 7' Carb. hydr. 14- .. ..7- .. ..14- 

 I* Carb. oxide 0-5 .. .. 0-5 .. .. 1» 

 2- Hydrogen ..1- 3- 



11-1 18-8 9-7 20-2 



The sums of the numbers thus theoretically obtained do not, it 

 is true, exactly correspond with the experimental ones; but they 

 approach as nearly as, from the nature of the subject, can be 

 expected, the greatest disagreement (that in the diminution by 

 firing) not much exceeding ^th of the observed amount. 



In a similar manner we may explain the composition of the 

 lighter and less combustible products obtained at advanced pe- 

 riods of the distillatioii. For example, a portion of the last pro- 

 duct of gas from cannel, distilled in a glass retort, gave the fol- 

 lowing results : 



Measures of gas . . . . 20 



Mixed with oxygen . . 30 =28 pure oxygen + 2 azote. 



Total .."so" 



Fired 22 



Washed with potash .. 18 = 14-7 oxygen + 5-3 azote. 



13"3 oxygen spent. 

 In this experiment, 1'3 more azote were found in the resi- 

 duum than can be traced to the oxygen employed. The com- 

 bustible gas was, tiiefefore, only 1 8 {- measures ; the carbonic 

 acid produced 4 ; the oxygen spent i3'3 ; and the diminution 

 by firing 28. The following supposed mixture will explain these 

 facts. 



Measures. Take Give Dimilu^heJ 

 of t3xyg. Carb. Acid. by firin^c. 

 2 Carb. hydr. ..4 .. ..2 .. ..4 

 2 Carb. oxide . . 2 . . . . 2 . . . . 2 

 15 Hydrogen.. .. 7i 22| 



19 13{ 4 281 In 



