II. On the influence of coal-dust in colliery explosions. No. V

Abstract

At the beginning of the first paper on this subject, which I had the honour of reading before the Fellows of the Royal Society now somewhat more than eight years ago (“Proc. Roy. Soc.,” vol. 24, p. 354), I gave a short account of what appeared to me to be a rational mode of explaining the occurrence of all great explosions in dry and dusty collieries; and since then I have had opportunities of studying several remarkable instances of this class of phenomena, with the result that I am now more than ever satisfied with the correctness of the views which I then expressed. It is true, as some subsequent writers, amongst whom I may name Sir Frederick Abel, F. R. S., have observed, that coal-dust had been previously recognised as a factor in colliery explosions. I think I may safely claim, however, that no earlier author had gone the length of crediting it with the role of principal agent, and relegating fire-damp to a secondary position. It is also admitted, I believe, by everyone familiar with the subject, that my experiments with mixtures of coal-dust and air containing a small proportion of fire-damp were original. Similar experiments were subsequently made by members of the North of England Institute of Mining and Mechanical Engineers, by a committee of the Chesterfield Institute of Engineers, by Professor Abel on behalf of the Home Office and the Royal Commission on Accidents in Mines, | and by others in this country, by MM. Mallard and Le Chatelier for the Commission du Grisou in France, and by others on the Continent, all of which led to the same conclusion, namely, that air containing too small a proportion of fire-damp to render it inflammable at ordinary pressure and temperature becomes so when coal-dust is added to it. Differences of opinion were expressed as to the actual proportion of fire-damp, the comparative fineness of the coal-dust, and the quality of the coal necessary to the attainment of this result, but the general conclusion, in every case, was the one I have stated above.