1882.] on Some of the Dangerous Properties of Dusts. 95 



members of the Eoyal Institution, in which he dealt with the substance 

 of the above report, and with the experimental inquiry made by 

 himself with reference to the provision of means for preventing a 

 recurrence of such disasters as that at Haswell. In a brief account of 

 this lecture published in the number of the Athenoeum following its 

 delivery, the substance of his remarks relating to the effect of coal- 

 dust is given in these words : " The ignition and explosion of the 

 (fire-damp) mixture would raise and then kindle the coal dust which 

 is always pervading the passages, and these effects must in a moment 

 have made the part of the mine which was the scene of the calamity 

 glow like a furnace." 



The report of Faraday and Lyell was published in the ' Philo- 

 sophical Magazine' for January 1845, and was followed by a letter 

 from Faraday in the February number of the same publication, in 

 which he referred to the lecture just delivered at the Royal Institu- 

 tion, and made further suggestions with respect to the method of 

 ventilating the mines suggested in the report. But it appears that 

 these publications remained long unknown in France, for in 1855 

 M. du Souich, Chief Government Mining Engineer of the Saint Etienne 

 arrondissement, when referring to an explosion which had occurred at 

 Firminy, advanced, as new, the view that the deposition of crusts of a 

 light coke upon the props was due to dust which was swept up and 

 transported to a distance by the violent current produced by the ex- 

 plosion, and which, being in part inflamed, would carry on and pro- 

 long the effects of the fire-damp. The fact that men near the pit's 

 mouth received burns and other injuries, while others who were in 

 workings near the seat of the explosion, but out of the main air- 

 current, escaped unhurt, was ascribed by him to this ignition and 

 carriage of flame by dust. Had the results of the explosion been 

 entirely due to the mine being highly charged with gas, the explo- 

 sion must, he considered, have extended to those portions. On the 

 occasion of two explosions in 1861, M. du Souich again dwelt upon 

 his views regarding the part played by coal-dust in increasing the 

 disastrous effects of fire-damp explosions. In 1864.-67, M. Verpilleux 

 instituted experiments which led him to the conclusion that coal dust 

 plays an important part in coal-mine explosions ; the subject was 

 also pursued by several other French mining engineers at about the 

 same time, and especially by M. Vital, who made some experiments 

 on a small scale, in 1875, in connection with an inquiry into the 

 nature and cause of an explosion which had occurred the year before 

 at the Campagnac Colliery, and in a part where no fire-damp had 

 ever been detected. An examination for gas had been made by the 

 overman with a Mueseler lamp just before a shot was fired, and after 

 the first shot, a second shot was prej)ared, and the fuze having been 

 ignited, the men retreated, when, after a short interval, an explosion 

 took place, and the men stated that they saw a body of reddish flame 

 advancing upon them. After examining the nature of dust collected 

 in the mine, and instituting some special experiments upon a very 



