DUE TO GAS DERIVED FROM COAL-DUST. 121 



9, and 10 explosions. Their lights burned brightly, and 

 they suffered no faintness during their exposure of over an 

 hour. This fact is of interest since Dr. Angus Smith 

 found, by experiment many years ago, that the flame of a 

 candle was extinguished in an atmosphere containing 2 

 per cent, of carbon dioxide, and over forty years ago Le 

 Blanc observed that an atmosphere containing 0' 54 per cent, 

 of CO caused faintness and death, and that it was due to 

 prolonged exposure to the very small percentages of this gas 

 in the gaseous products of colliery explosions, that from 

 80 to 85 per cent, of the deaths were due, and these facts 

 have been constantly verified. The burning candles of the 

 survivors at Camerton Collieries indicate the absence of 

 more than 2 per cent, of COo ; and their escape, the 

 absence of 0'54 per cent, of CO in the still atmospheres. 



These small quantities of the oxides of carbon show that 

 the carbon constituent of the hydrocarbons was not appre- 

 ciably oxidised, and the presence of the carbon in copious 

 suspension in the gaseous products, with its profuse and 

 general deposition upon the side walls throughout the fields 

 of explosion, is the evidence of fact that it was almost 

 wholly separated from the hydrogen, and not oxidised. 

 The amorphous carbon, therefore, had its origin in the educts 

 of the coal, and was removed from the sphere of action, 

 leaving hydrogen for effecting the phenomena of the ex- 

 plosions. 



Attention may now be turned to the phenomena at the 

 origin of the explosion, as, if the chemical changes from the 

 point of origin to the first hydrogen explosion be elucidated, 

 the propagation along the paths of coal-dust will present no 

 difficulty. 



The heat of the exploded powder was first employed in 

 breaking and displacing a small portion of rock, and in 



K 



