February 9, 191 1] 



NATURE 



487 



A 



n 



EXPERIMENTS ON COAL-DUST 

 EXPLOSIONS.^ 



PRELIMINARY record of experiments made wUh 

 coal dust, and other work of various kinds, carried 

 out by a committee of colliery owners on behalf of the 

 Mining Association of Great Britain, has lately been pub- 

 lished in an elaborate and splendidly illustrated volume. 



In the introductory chapter the committee quotes the 

 remarks of John Buddie (1803) regarding " the shower of 

 red-hot sparks of the ignited dust which were driven along 

 by the force of the explosion," and those of Faraday and 

 Lvell (1884) : " There is every reason to believe that much 

 coal gas was made from this dust in the very air of the 

 mine, by the flame of the firedamp which raised and swept 

 it along, and much of the carbon of this dust remained 

 unburnt from want of air."- A general list is then given 

 of those who have taken part in the investigation since 

 1875 (not 1870 as stated), regardless 

 of chronological order, and reference is 

 made to the opinions expressed by the 

 Royal Commission, 189 1-4, and of a 

 committee consisting of the members of 

 the Royal Commission of 1906, which 

 is still in existence, and an advisory 

 board associated with it, to the effect 

 that experiments with coal dust should 

 be made on a larger scale than any 

 hitherto undertaken. The circumstances 

 which induced the Mining Association of 

 Great Britain to undertake to find the 

 necessary funds, which were estimated 

 at 10,000/., are also described. 



The committee illustrates in cross- 

 section some of the different galleries in 

 which previous coal-dust experiments 

 were made, as well as those now being 

 employed in France and England, 

 and finally sums up the results 

 of the work of its predecessors 

 as follows : — " These galleries or 

 tubes have in no instance been of 

 sufficient size to allow of the 

 conditions prevailing in a mine 

 being, reproduced." " Neither 

 were they of sufficient length to 

 obtain the development of ex- 

 plosive force nor of sufficient 

 strength to resist the latter if 

 obtained. The inflammability of 

 coal dust had been demonstrated 

 by Faraday." 



.Again, in the first paragraph 



of chapter iii. the committee 



says : — " As has already been 



stated in the Introduction, one 



of the most 



~. — ._. ta|<iLi. cunHtn 



;:--•«».-.. I»NITCK 



-i. 



^ 

 ^ 



, important 

 i=of this 



Fig. 



objects 

 inquiry 

 has been to 

 demonstrate a s 

 conclusively a s 

 possible the great 

 danger that exists 

 from the presence 

 of coal dust on 

 the roadways of a 

 mine, and by ensuring the absence of gas to definitely 

 establish the fact that it is not essential that firedamp in 

 addition to coal dust should be present for an explosion 

 to be propagated." 



These historical references are singularly curt and in- 

 exact. Whatever may have been the actual motive that 

 dictated them, they have the appearance of being an 

 attempt to set aside any possible claim to having done 

 really useful work by those who occupied the field in the 



- "Record of the First Series of the British Coal Dust Experiments, con- 

 ducted by the Committee .Appointed by the Mining Association of Great 

 Britain. A Record of the Experiments carried out during 1908 and 1900 at 

 U»e Altofts Experiments Station." Pp. viii-f 212. (London ; The Colliery 

 Guardian Co., 1910.) Price lor. net. 



•* The itahcs are the reviewers. 



NO. 2154, VOL. 85] 



interval between the time when Faraday showed by an 

 experiment that flame is enlarged when coal dust is allowed 

 to fall upon it and the present day. They appear to 

 simulate ignorance of the fact that the dangers due to the 

 presence of coal dust, both with and without the simul- 

 taneous presence of firedamp, was conclusively proved long 

 ago — the explosion at Altofts Colliery in 1886 {Proc. Roy. 

 Soc, vol. xlii. 1887) having been, itself, the culminating 

 proof on a gigantic scale of the second alternative. 



Does the British colliery owner, as personified in the 

 committee, hope, by thus assuming the airs and manners of 

 Sir Oracle to conceal his own laches in having hitherto, 

 with few exceptions (of whom the late Mr. Archibald Hood 

 may be taken as the most brilliant example), contributed 

 nothing towards the solution of the coal-dust question, but 

 contented himself with classifying those who were bearing 

 the burden and heat of the day as faddists and theorists? 



One can understand the grief and dismay of the French 

 Government engineers who, by their inept criticism of the 

 present writer's experiments and conclusions and of his 

 description of Penygraig explosion (1880) (Proc. Roy. Soc, 

 No. 219,. 1882), and by their own abortive experiments 

 with coal dust, lulled themselves and their fellow-country- 

 men to sleep twenty-eight years ago, on being rudely 

 awakened by the Courriferes explosion, with its holocaust 

 of more than iioo men. 



One can sympathise with the confusion of the United 

 States Government engineers at being caught lagging in 

 the rear of an important movement. 



But it is difficult to understand why one's own country- 

 men should be less generous than were the Prussian 

 Government engineers, who showed Sir VV. Thomas Lewis 

 and the present writer a most violent explosion of air and 

 coal dust, " without any admixture of firedamp," in their 

 gallery at Neunkirchen on October 25, 1884, frankly 

 avowed that they drew their inspiration from the present 

 writer's earlier work, volunteered the statement that he 

 was the inventor (sic) of the method of proving the 

 explosiveness of coal dust in an experimental gallery, and 

 added that his gallery of 1880-1 (for which the Govern- 

 ment Grant Committee of the Royal Society provided the 

 funds) had served as a model for their own. 



These blots upon a work that is otherwise admirable 

 in many respects ought to have been avoided at every 

 hazard. There u'as plenty of room for the colliery owner 

 to come in with his gigantic apparatus to demonstrate the 

 dangers of coal dust to himself, his officials, and the com- 

 munity in general, without having to push others aside in 

 the process. 



The demonstrations with the Altofts apparatus are so 

 overpoweringly convincing that, in the opinion of the 

 present writer, the Government ought to make it obliga- 

 torv on the part of everyone who holds a mine manager's 

 certificate to have seen them. They constitute, as the 

 committee itself properly observes, the most important 

 function of the apparatus, before which all the other 

 questions which it proposes to investigate pale into 

 obscurity. 



The second chapter is devoted to a description of the 

 experimental gallery, the method of preparing the dust, 

 and the means of raising and igniting it. 



That part of the apparatus (Fig. i) in which the 

 explosions are effected is a straight tube AB, 7 feet 

 6 inches in diameter, made up of the outer shells of 

 steam boilers with their ends abutting against, and fixed 

 to, each other, 600 feet long, open at one end, closed at 

 the other, and with a branch CD, 6 feet in diameter, also 

 made up of boiler shells, which extends at right angles 

 from the closed end of the tube AB to an exhausting 

 ventilating fan at E. 



The branch CD is bent four times at right angles to 

 itself, and is provided with two relief valves at each l)end, 

 one at .A, and another opposite the junction at C, making 

 ten altogether, which open when an explosion takes place, 

 and thus protect the fan from injury*. A segment in the 

 bottom of the explosion gallery, with an arc •? feet wide, 

 filled with concrete, constitutes a level floor on which a 

 line of rails of 25-inch gauge is laid. The rails rest on 

 sleepers 3 feet apart, embedded in the concrete. Five rows 

 of wooden shelves, 5 inches wide by i-inch thick, fixed on 

 iron brackets, extend along each side of the gallery from 



