MOUNT KEMBLA COLLIERY. 233 



As to the evidence of heat ; eye-witnesses saw flame burst from 

 the mine, and this is supported by the microscopical and 

 analytical examination of the coal dust taken from various 

 places, chiefly from the No. 1 Right Main Engine Road. These 

 show visible signs of coking, and taking the average Kemblu 

 coal to contain 23 per cent, of volatile hydrocarbons, the loss of 

 this hydrocarbon due to distillation varied from 4.09 to 5G.35 

 per cent. Mr. Ming-aye, analyst and assayer to the Depart- 

 ment of Mines, concludes that the particles had been subjected 

 to a flame at a temperature represented by a cherry-red heat, 

 700deg. to &UOdeg. Jb'ahrenheit. Some of those witnesses who 

 supported the wind-blast theory quoted the experiments made 

 by Professor Bedson, who found that a mixture of coal dust and 

 air would ignite at a temperature of 291deg. Fahrenheit ; but 

 it must be remembered that in these experiments the heat was 

 .applied gradually, so that there was time for firedamp to 

 be distilled from the very fine dust before the actual ignition 

 took place; then, even if one supposes 291deg. Fahrenheit was 

 attained by the sudden compression of air to 351b. to the 

 square inch, which is highly improbable, the condition not 

 being the same, they cannot in fairness be compared. Besides, 

 the indications are that the ignition of an inflammable mixture 

 of firedamp and air took place about the junction of the 4th 

 Right Rope Road with the No. 1 Right Main Level, and there 

 being two openings at this point, any heat resulting from com- 

 pression would be very greatly lowered by re-expaiisioii The 

 Commission, after carefully weighing all evidence, came to 

 the conclusion that a fall in the 35-acre waste drove an inflam- 

 mable mixture of firedamp and air down the 4th Right Rope 

 Road to the No 1 Right Main Level with sufficient force to 

 cross the Travelling Road without distributing itself in that 

 road to any great extent. The mixture driven into the Main 

 Level, with a tendency to travel rather outbye than inbye, 

 owing to the angle at which the 4th Right meets that road, 

 met the intake air current, which retarded its forward move- 

 ment, so that its centre came to be about the 4th Right Junc- 

 tion. The northern extremity of the mass spreading inbye 

 along the Main Level, reached a wheeler's naked light at the 

 4th Left, which sent a flash of flame back, communicating the 

 ignition to the whole body, the explosion being made more 

 violent by the presence of coal dust raised by the first blast. 

 Thus the centre of force showed itself at the centre of the ex- 

 plosive body, and not at the point of ignition. The firedamp 

 and air exploded, and in turn started a series of explosions of 

 coal dust in such quick succession as to be practically one in- 

 stantaneous explosion, receiving fresh accessions of force as 

 it reached fresh supplies of oxygen in the air-courses traversed. 

 These explosions of firedamp and coal dust generated a large 



