DUE TO GAS DERIVED FROM COAL-DUST. 115 



local body of methane and air, was utterly inadequate to 

 account for the explosive phenomena found through such 

 distances ; and the source of the immense quantities of heat 

 necessary for the propagation of the explosion beyond the 

 boundaries of the original explosive mixture, or the vicinity 

 of the blasting charge, had not been investigated. Not- 

 withstanding what has been placed before the scientific 

 world concerning the part taken by coal-dust in colliery 

 explosions, with the ignition of small accumulations of 

 methane and air, or the explosion of small charges of blast- 

 ing substances as the sole source of heat, an explanation of 

 the phenomena of the explosions was still wanting. 



Up to this date, 1893, all the colliery explosions in the 

 United Kingdom had occurred in mines known to contain fire- 

 damp; but an explosion now happened at the Camerton Col- 

 lieries, Somersetshire, followed by another at the adjoining 

 Timsbury Collieries. Methane had not been found in these 

 collieries during their history of seventy to one hundred 

 years. Coal-dust was the only material in the mines capable 

 of giving rise to explosion and coextensive with the field of 

 explosive phenomeca. The explosions therefore offered 

 opportunities for observing the deportment of coal-dust in 

 the absence of methane, upon the scale of a colliery explo- 

 sion, and in the ordinary conditions of coal-mining. The 

 observations and measurements of the effects in the mines 

 occupied me eight days ; and as they provide the evidence 

 from which the energies which produced them are to be 

 elucidated, it will now assist the discussion if we consider 

 the observations. 



The plan of Timsbury Collieries exhibits the field of an 

 explosion. The shot that originated this disaster is indi- 

 cated, with the successive loci of disruption, which it will 

 be observed were at intervals in the tunnels. 



