DUE TO GAS DERIVED FROM COAL-DUST. 117 



rails as they had been left, the wagons uninjured, and 

 their contents again undisturbed. 



These observations show that the tunnels, with the timber 

 supports and arches, and the materials they contained, at 

 the loci of the disruptions and in the intervals between, 

 were of equal strength ; consequently the resistances they 

 offered to destruction were identical, and the contrasts in 

 their condition exhibited, in juxtaposition, the effects of 

 disruptive energy and their absence. The phenomena in 

 the disruptions and the phenomena in intervals therefore 

 exhibit distinct modes of energy. 



The materials displaced in the disruptions were found 

 lying in opposite directions, or in radial lines, and exhibited 

 the effects due to local explosions. The destruction recorded 

 could only be caused by forces moving at the immense 

 velocity known in the ignition of explosive mixtures ; and 

 this is obvious when it is remembered that the disruptive 

 energy was exerted through the instrumentality of a mass 

 of air which, by impact, wrought the shattering effects 

 observed, and must therefore have moved at the immense 

 velocity referred to. 



The condition of the tunnels in the intervals from disrup- 

 tion to disruption, shows that the disruptive energies were 

 expended at the loci of the explosions, and that there was a 

 comparatively slow gaseous movement between them, which 

 allowed time for the distillation of the coal and the forma- 

 tion of the explosive gaseous mixtures, to the ignition of 

 which the successive local explosions were due. 



The field of disaster at Camerton Collieries presented the 

 effects of ten local explosions at intervals in the paths of 

 coal-dust, approaching one mile in length.* 



* Coal-dust an Explosive Agent, pp. 29, 30. 



