210 



Chemical Exmnination of the Firc-Dmnp, 



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

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

 trials with the same gas the indications hardly ever diifered 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 which the Gas waa collected. 



j3 



Specific Gravity. £ oi 

 Observed Calcul s ^ 



1. 



2. 

 3. 



4. 



5. 



6. 



Benshara Coal Seam, Wallsend Collie- 

 ry 



Yard Coal Seam, Burraton Colliery, 



Hi^h iMain Seam, Killingsvvorth Col- 

 liery 



Low Main Seam 



liery 



, Killingworth Col- 



7. 



8. 



9. 

 10. 



11. 



12. 



Marquis of Londonderry 'sPcnsher Col- 

 liery, from the Hutton Seam Waste, 

 125 fathoms deep, . . , . . . 



Marquis of Londonderry 'sPittinglonCol- 

 liery, Adelaide Pit, Ilutton Seam, 

 45 fathoms below tlie surface, 



Epplefon Jane Pit, Hutton Seam, Ilet- 

 ton Colliery, 175 Hithoms below the 

 surface, 



Blossom Pit Main Coal Seam* Hetton 



Colliery, 100 fathoms below the sur- 

 face, 



Bcnsham Coal Seam, Jarrow Colliery 

 Jarrow Colliery Seam, 11 fathoms be- 

 low No. 9, 



Bensham Seam, Willington Colliery 

 145 fathoms from the surface, . . 



0G024 0-5901 91 

 0-600 0-5903' 93 



0-6196' 0-6236 85 



0-8226 0-8325' 37 



0-966 



0-9662 



8 

 465 



866 



7 



82 



7 

 16-5 



11 



0-747 



0-8755 28 67-5 4-5 



0-7677 



50 



0-78 10-7724' 50 

 0-63810 641 81-5 



0-6209 0-6079 89 



6 



23 

 18.5 



11 



44 





 











7278 

 1- 



7175 

 1 



68 128-7 









100 



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. 



