150 ON THE FIRE^I>A*lt> OF COAL MINES. 



Component ()3'34 atmospherical air 



i)arls * 1 -66 carbonic acid 



35* inflammable gas 



100- 



Thcinflam.gas The nature of the inflammable gas was next ascertained 

 hWro'en r * ^y detonation with oxigen gas. Reducing the results to a 

 general average, and excluding the common air, the really 

 inflammable part of the gas required for combustion about 

 twice its bulk of oxigen; and gave its own volume of car- 

 bonic acid. Hence the inflammable portion of the gas was 

 carburetted hidrogen. From the experiments of Mr. Dal ton 

 on the gas from stagnant water, and my own obtained by 

 distilling pit-coal*, the fire-damp appears to differ very lit- 

 tle from both those gasses. 

 Fire-damp less It was desirable, however, to repeat the analysis of fire- 

 examined by** ^amp, * ess adulterated with common air ; and for this pur- 

 Dr. Thomson, pose a quantity was collected (as it issued through water on 

 the floor of the mine) in an inverted bottle, which was well 

 corked and tied over with bladder. Happening to pass 

 through Newcastle last spring, I carried this gas with me to 

 Edinburgh ; and, having no opportunity of making experi- 

 ments upon it there, my friend Dr. Thomson was so good 

 as to undertake its analysis, and to furnish me with the fol- 

 lowing results. 

 Detail of the From the action of nitrous gas and of lime-water, the gas 

 andTesul" 5 a PP tare d by Dr. Thomson's experiments, to contain, in 100 

 measures, 



63 inflammable gas 



6 *5 oxigen 

 Z5'5 azote 



5* carbonic acid 



100-0 



* The gas obtained by the destructive distillation of coal I have 

 found to contain a variable proportion of sulphuretted hidrogen, and to 

 differ somewhat from the composition which I have stated in the 11th 

 vol. of this Journal. The correction of those results 1 reserve for ano- 

 ther occasion. 



The 



