54 F. B. GUTHRIE AND A. A. ATKINSON. 



Analyses of samples of Air. 



No. 



Oxygen. 



Carbon dioxide. 



Nitrogen. 



1 



20-03 per cent. 



0-19 per cent. 



79-78 per cent. 



2 



19-32 „ 



0-27 „ 



80-41 „ 



3 



19-28 „ 



0-31 „ 



8041 „ 



4 



20-03 „ 



0-24 „ 



79-73 „ 



Tests, with negative results, were made in the mine for marsh 

 gas by means of the Clowes' hydrogen lamp, which is able to 

 detect the presence of 0*25% of this gas. If present, therefore, 

 it was in less quantity than -£%. Carbon monoxide was absent 

 in all cases. The amount of moisture in the air was not determined. 



Ordinary air was also examined by the same methods of 

 analysis as were adopted in determining the oxygen and carbon 

 dioxide in the above samples and gave : — 



Oxygen. Carbon dioxide. 



Ordinary air 20-9 per cent. 0*03 per cent. 



The following table accordingly shows the deficiency in oxygen 

 and the excess of carbon dioxide in the samples examined as 

 compared with ordinary air: — 



No. Deficiency in oxygen, %. Excess of carbon dioxide, %. 



1 0-85 0-16 



2 1-55 0-24 



3 1-59 0-28 



4 0-85 0-21 



The quantity of carbon dioxide found in the worst sample (No. 

 3) is considerably below the amount found to be injurious in 

 dwelling rooms. Professor Lehmann 1 quoting the results of some 

 of the most recent investigations (lts93) on this subject, shows 

 that the presence in the air of dwelling rooms of 1 to 2% carbon 

 dioxide causes only trifling symptoms after several hours. 



Analyses of samples of air in collieries are not numerous. In 

 the Transactions of the Federated Institute of Mining Engineers, 



1 Methods of Practical Hygiene, Translation by Sir W. Orookes, Vol. I.; 

 p. 276. 



