222 Original Articles. [April, 



turies old, and existed before great depths were attained — forgetting 

 too, that the air is not bad in proportion to the depth — forgetting too, 

 that unerring instinct of the miner which for ages has led him to fear 

 the foul air and the " demon of the mine," which sometimes strikes 

 him suddenly dead with his foul breath.* The greatest evils from the 

 air are felt when the men are down the mine, not after they have risen 

 to the surface and are suffering from fatigue ; but the great depth may 

 and does cause some of the most dangerous symptoms after the ex- 

 haustion of mounting. Let us be satisfied that every evil demands a 

 cure, and if one evil be somewhat smaller than another, let us never- 

 theless seek to eradicate it. We believe the greatest evil to be foul 

 air ; perhaps also, from some bigoted feeling, and perhaps because we 

 know most about it ; but we cannot cease to admire him who dimi- 

 nishes the labour of mounting the ladder steps. 



The author of this paper examined the air of the mines and has 

 given, in his report, an analysis of several hundred specimens. This 

 report begins first by inquiring into the composition of the air. 

 Hitherto it has been given with differences of one-tenth per cent., or 

 one thousandth part, forgetting how much one in a thousand of air is, 

 and that we can trace in a moment the presence of some substances 

 even to a millionth, perhaps far beyond this. The air at various 

 times and in various places was found to differ in the amount of 

 oxygen. The author does not suppose that the loss of the minute 

 amounts of oxygen in some of these cases is of consequence, except as 

 an indication of the presence of other gases. It may even be that in the 

 higher numbers with small differences some uncertainty exists, but as 

 a whole, the gradation in the following table came out after arranging 

 five or six hundred analyses, and was entirely unexpected. 



Analyses of air varying in the amount of oxygen (per cent.) : — 



N.E. Seashore and open heath of Scotland . . . 20-999 



Tops of hills— Scotland 20*98 



Base of hills — Scotland 



Suburb of Manchester in wet weather .... 2l>98 



Front Street — f mile from Exchange — dry . . . 20 - 945 



Back of house 20-936 



Unhealthy parts of Perth — favourable or windy day . 20*935 



Fog and frost in Manchester ...... 20'91 



Sitting-room which felt close . . . . . 20 '89 



After six hours of a petroleum lamp .... 20'83 



Pit of Theatre 20-74 



Gallery ■ 20-36 



When candles go out ....... 18-5 



Difficult to remain in 17*2 



This table is given in order to enable us to compare the air of 

 mines with purest air and with ordinary bad ventilation. The closest 

 gallery of a theatre did not lose above one-third the amount of oxygen 

 lost in the average of all the mine air. How low the amount must in 

 many cases have been to produce this low average may be imagined, 



* If this seems only a metaphor jt was none to the old miners, who have left 

 descriptions of several species of demons. 



