210 



Chemical Examination of the Fire-Damp. 



cations in my trials were uniform, and very nearly true. Apply- 

 mg the same method to fire-damp, I found that in two or more 

 trials with the same gas the indications hardly ever differed so 

 much as 1 per cent, of oxygen ; and in general, as in several in- 

 stances already given, the coincidence in different experiments 

 was exact. Having now mentioned all that appears necessary to 

 elucidate the chemical nature of the different samples of fire-damp 

 from the mines of Newcastle, I conclude this account of the ex- 

 amination by inserting a tabular view of the composition of all 

 the gases which have been analysed. 



Mines in wliich the Gas was collected. 



Specific Gravity. I gw 

 Observed Calcul g 6 





Garb 

 acid 



Bensham Coal Seam, Wallsend Collie 



ry, 



Yard Coal Seam, Burraton Collieiy, 



High Main Seam, Killingswortli Col- 

 liery, 



Low Main Seam, Killingworth Col 

 liery, 



Marquis of Londonderry's Pensher Col- 

 liery, from the Hutton Seam Waste 

 125 fathoms deep, ...... 



Marquis of Londonderry 'sPittingtonCol- 

 liery, Adelaide Pit, Hutton Seam, 

 45 fathoms below the surface, 



Eppleton Jane Pit, Hutton Seam, Het 

 ton Colliery, 175 fathoms below the 

 surface, 



Blossom Pit Main Coal Seam, Hetton 

 Colliery, 100 fathoms below the sur 

 face, 



Bensham Coal Seam, Jarrow Colliery, 



Jarrow Colliery Seam, 11 fathoms be- 

 low No. 9, 



Bensham Seam, Willington Colliery, 

 145 fathoms from the surface, . , 



0-6024 0-5991! 91 

 0-600 1 0-5903: 93 



0-6196' 0-6236 85 



0-8226 0-8325! 37 



0-966 ! 0-9662 



866 0-8755 



0-747 



0-78 

 0-6381 



0-6209 



0-7278 

 1- 



0-7677 



0-7724 

 641 



0-6079 



07175 

 1 



28 



50 



50 

 81-5 



89 



63 

 



46-5 



82 



67-5 



6 



23 

 18.5 



11 



28-7 

 100 





 



7 



16-5 



11 



4-5 



44 



27 

 









 





 3-3 



The gas, No. 12, proved to be unmixed air. I have no re- 

 marks to offer respecting the nitrogen found in some 'samples of 

 the fire-damp beyond what will readily occur to other chemists, 

 who, I apprehend, will consider its presence as a simple conse- 

 quence of oxidizing processes, especially of metallic sulphurets, 

 abstracting oxygen from atmospheric air. 



