388 Dr. Turner's Chemical Examination of the Fire Damp 



II. Analysis of a gas from the Bensham Coal Seam, Jarrow Colliery, collected 



from a blower, which caused the accident in 1826. 



Specific gravity actually observed, = 0*6381 



This gas was quite free from carbonic acid gas. In two trials with ni- 

 trous gas it was found to contain 3"7 per cent, of oxygen, equivalent to 

 18*5 of air. A gaseous mixture of 18 - 5 air, and 8T5 real marsh gas, should 

 have a specific gravity of 0*641, since 0-5595 + 0-815 + 0-185=0-641. 



Of this gas 13'5 measures, inferred from the foregoing premises, to con- 

 tain 05 of oxygen, and 11 of real marsh gas, were fired with 30 measures 

 of oxygen, which contained 28*8 of real oxygen gas. 



Loss of volume due to production of water, = 22'8 



Carbonic acid gas generated, = 11-2 



Residual oxygen, — 6*4 



Deducting 17'6 from 29'3 there remain as — 

 Oxygen gas which went to the production of water, = 11*7 



III. Analysis of a gas from the Eppleton Jane Pit, Hutton Seam, Hetton 

 Colliery, collected at a depth of 175 fathoms below the surface. 



Specific gravity actually observed, = - 78 



This gas was quite free from carbonic acid. Two experiments with ni- 

 trous gas, agreed in indicating the presence of 4" 6 per cent, of oxygen, 

 equivalent to 23 measures of air. Analysis indicated the presence of 50 

 per cent, of real marsh gas, leaving 27 per cent, as nitrogen, independently 

 of that already considered as atmospheric air. 



Of this gas, 11 measures, containing - 5 of oxygen, were fired with 28 

 of oxygen gas, which contained 26'9 of real oxygen. 



Loss of volume due to formation of water, = 10 - 5 



Carbonic acid gas generated, = 5-5 



Residual Oxygen, = 16*4 



Deducting 5-5 + 16-4=21-9 from 27 4, there re- 

 main as — 



Oxygen gas which went to the formation of water, = 5 - 5 

 A gaseous mixture, consisting of 50 measures of real marsh gas, 23 of 

 air, and 27 of nitrogen, should have a specific gravity of - 7724, since 

 0-5595+0-5+0-23+0-9727+0-27=0-7724. 



