Distance from 

 shaft in feet. 



Temp. 

 F. deg. 



Defficiency 

 of oxygen. 



Excess of 

 carbon dioxide 



150 



74 



0-37 



0-10 



5,850 



78 



0-36 



0-10 



7,920 



80 



0-77 



0-26 



9,150 



83 



1-70 



047 



150 





0-24 



0-095 



7,920 





1-16 



0-29 



9,150 





1-20 



0-33 



6,900 





1-26 



0-33 



ANALYSES OF AIR FROM COAL MINES. 55 



Vol. xvi , are some analyses by Dr. Haldane of samples of air 

 from the return airways in the Hamstead Colliery, South Stafford- 

 shire, England, which are given in the following table: — 



Road. 



A. Main north return airway 



B. North return airway 



C. Return airway 



D. Return airway 



E. Main south return airway 



C. Return airway 



D. Return airway 



F. Return airway 



In comparing these results it may be pointed out that all the 

 samples taken from the Wallsend Colliery were from the worst 

 part of the return airway, and they cannot be fairly compared 

 with samples A. and E. in the above table, which represent com- 

 paratively pure air close to the shaft. They compare favourably 

 with samples C, D., and F., and are noticeably lower in carbon 

 dioxide. 



Analyses of air in return airways from other mines are to be 

 found in the Transactions of the Federated Mining Institute. 1 

 These analyses show the air iu these places to be of similar com- 

 position to that in the return airways at Hamstead. 



On account of being safer, the return airways are often used in 

 England as travelling roads, and it is fair to assume that the air 

 in the returns so used does not differ materially from the samples 

 above quoted, nor from the air in the Lambton heading of the 

 Wallsend Colliery. 



In one of the papers above referred to 2 Dr. Haldane shows that 

 a considerably greater deficiency of oxygen and a corresponding 

 excess of carbon dioxide can be borne before the breathing becomes 

 noticeably deeper. The point at which the breathing was found 



1 Vol. viii., p. 554, and Vol. xi., p. 272. 

 3 Trans. Fed. Min. Inst., Vol. viii., p. 557. 



