On the Influence of Coal-dust in Colliery Explosions. 493 



Four of the five men who escaped with their lives were in the 

 heading d at the time of the explosion. They saw the flash, but were 

 not burnt. The fifth, who was working in a cul de sac at e, was 

 slightly burnt, and remained unconscious for many hours. The 

 unshaded galleries on the plan, except d, show the universal 

 distribution of the flame, which must also be supposed to have passed 

 over the ground covered by falls of roof due to the explosion. The 

 shaded patches show the points at which the evidence of a high 

 temperature, such as really charred timber and thick deposits of 

 coked coal-dust, were strongest. It will be seen that each of these 

 points was either in a cul de sac, or was approachable from two 

 opposite directions. 



2. Five or six of the seventeen bodies found between the points 

 1) and e in the main heading were in a kneeling posture, their mouths 

 were covered with their hands, and their faces were pressed into the dust 

 on the floor. One body in the roadway I was in the same position ; 

 another near him was lying on his side with his coat drawn closely over 

 his mouth and nose, and held tightly with one hand ; and a third, lying 

 at the opposite side of the roadway, had his mouth pressed on the ground, 

 his head having been twisted round to some extent so as to admit of 

 this. I observed that two of the first group and the three constituting 

 the last group had been burnt after they had assumed these positions, 

 but unfortunately I did not particularly examine the others, as they 

 had been removed before the true significance of these circumstances 

 had dawned upon me. 



3. There were deposits, or crusts, of coked coal-dust in every 

 working place in the mine (from the district with the two small arrow- 

 heads above the upcast shaft to the district g above the downcast 

 shaft at the opposite extremity), that is to say, ivhere the coal-dust was 

 comparatively free from impurities, and capable of adhering to the 

 timber and other objects when thrown against them in a fluid or 

 semi-fluid state. On the other hand, the same kind of deposits were 

 very rare, and for the most part entirely absent, in the main roadways 

 through which the flame must necessarily have passed in travelling 

 from one district to another, that is to say, where the coal-dust was 

 largely mixed with shale-dust and other impurities, and consequently 

 incapable of cohering when heated. 



The following table of analyses which the late Professor A. Freire- 

 Marreco, of Newcastie-on-Tyne, kindly prepared for me, shows the 

 composition of the coal itself, that of the dust from the floor, &c, 

 and that of the so-called coked coal-dust. 



Each number on the table corresponds to the same number on the 

 plan, which indicates the spot at which the sample in question wae 

 collected. 



