I'EBRUARY 2 2, I912] 



NATURE 



569 



ibeen filled with an inflammable mixture before the disturb- 

 ance began." 



It was demonstrated a few years later (Proc. Roy. Soc, 

 :No. 219, p. 437), by means of a larger apparatus built at 

 Llwynpia Colliery with funds provided by the Lords of 

 ■Committee of Council on Education, at the instance of the 

 Royal Society, that a mixture of air and coal-dust from 

 the same sources and of the same quality as that which 

 had been used in my first experiments was inflammable 

 at ordinary pressure and temperature. The cloud of coal- 

 dust thrown out of that apparatus into the open air, in 

 some instances from 30 to 50 feet long by from 10 to 15 

 feet in diameter at its widest part, was permeated with 

 rolling flames in identically the same manner as, although 

 ■ on a smaller scale than, the corresponding clouds ejected 

 from the larger apparatus at Altofts and Lidvin. 



It might have been expected that this final proof would 

 have settled the question definitely ; but, as its subsequent 

 history shows, the number of those who began to discuss 

 it has been so great, and their opinions so diverse, that 

 but little progress has been made during the thirty years 

 that have since elapsed. 



The object of my experiments was to elucidate the causes 

 of great colliery explosions. They were a means to that 

 end, and nothing more. For it appeared to me that if 

 once the causes were known a means of prevention would 

 be easily discovered, but that, so long as explosions con- 

 tinued to be attributed to outbursts of gas, which could 

 ■neither be foreseen nor prevented, the safety lamp would 

 be looked upon as the miners' only shield against a 

 •constantly threatening danger. 



Proneness to attribute all explosions to firedamp was the 

 real stumbling-block to progress. It held the French 

 engineers and many others in bondage for thirty-one years 

 after 1875, ^"d was only finally and effectually removed 

 by the occurrence of the Courri^res explosion and the 

 sensational phenomena subsequently revealed in the e.xperi- 

 ments at Altofts and Li^vin. 



After arriving at the conclusions narrated above, I 

 sketched out in another article, which was published in 

 Iron in 1878, what appeared to me to be two necessary 

 additions to the Coal Mines' Regulation Act, as follows :— 

 (i) " No shot must, on any pretence whatever, be fired 

 in a dry mine until the floor and sides of the working 

 place, or gallery, in which it is situated have been 

 •drenched with water, and rendered artificially damp, to a 

 distance of at least 15 yards from the shot-hole." 



(2) " In every naturally dry mine water shall from time 

 to time be sprinkled on the roadways, and in the neigh- 

 bourhood of the working places, in sufficient quantities to 

 render them damp at all times, both by night and day." 



In 1S86 the first of these two rules was adopted in the 

 Coal Mines' Regulation Act, 1886-7, but 20 yards was 

 specified instead of 15 ; the second was voluntarily adopted 

 almost immediately in many mines in South Wales and 

 elsewhere, and was made compulsory by the Prussian 

 Government in 1899-1900, but is not ' insisted on bv the 

 law of this country. 



I can still conceive of no better safeguard against the 

 dangers of shot-firing than that of rendering the dust harm- 

 less with water in the manner now specified in the Coal 

 Mines' Regulation Act, provided it be properly carried out. 

 \s regards the second precaution, I am now of opinion 

 .hat universal watering might be safely dispensed with if 

 a zone of wet ground of adequate breadth were created 

 round about every accumulation of explosive gas or every 

 point at which such an accumulation is liable to occur in 

 ■open spaces near the working places or accessible to the 

 workmen. 



Although French engineers hq^i taken a prominent part 

 in the assigning of a certain rdle to coal-dust thirty or 

 forty years ago, they rejected the coal-dust theory from 

 the first, and continued to oppose it until within the last 

 few years, concentrating the whole of their attention, as 

 M. Taffanel tells us, upon discovering the best means of 

 dealing with firedamp. As an indication of their attitude, 

 I may quote the words of M. H. Le Chatelier, who, writing 

 in 1890 regarding the three supposed special causes of 

 s explosions, viz. barometric variations, coal-dust, and out- 

 bursts of gas, expressed himself as follows : — 



" The first is purely imaginary, the second is insignifi- 



NO. 2208, VOL. 88] 



cant in the absence of explosive mixtures of firedamp and 

 air, the third alone is really serious, but happilv it occurs 

 only under very e.xceptional circumstances.'" 



It is remarkable, therefore, that the sudden blow which 

 eventually shattered this oppo==*ion and brought the coal- 

 dust question into world-wide prominence, namely, the 

 great disaster at Courri^res Colliery in 1906, in which more 

 than 1 100 men perished, should have fallen upon France 

 herself. The effect was immediate ; commissions and com- 

 mittees were hastily called together or revived, thousands 

 of pounds were forthcoming for experiments, apparatus on 

 a comparatively gigantic scale was erected in England, 

 France, and the United States, and experiments were re- 

 sumed in an artificial gallery in Austria that had been 

 disused for several years. 



In the midst of this great awakening in the coal-mining 

 world, the Mines Department of the Prussian Government, 

 which formulates and promulgates the laws governing the 

 safety of the Westphalian coal mines, remained apparently 

 unmoved. 



In 1884 the Prussian Firedamp Commission made ex- 

 periments witn coal-dust on a fairly large scale in an 

 artificial gallery at Konigsgrube, Saarbriicken, some of 

 which were seen by Lord Merthyr and myself on 

 October 24 of that year. The dust employed in these ex- 

 periments was collected from the floors of various collieries 

 producing coal of different qualities, and as it was sub- 

 mitted to the test without having been sifted to remove 

 the coarser particles and reduce it to a uniform degree of 

 fineness, the different kinds naturally gave different results. 

 As a consequence, the commission reported that although 

 some kinds of dust produced explosive phenomena, and 

 were therefore highly dangerous, others did not do so 

 under the same conditions, and might, therefore, be con- 

 sidered safe. Acting under this impression, they recom- 

 mended, first, a system of watering in a general way in 

 dangerous mines ; secondly, the use of brisant and short- 

 flaming explosives in place of gunpowder in all dusty 

 mines ; and, thirdly, the thorough damping of flie dust for 

 a distance of at least 10 metres in front of every blasting 

 shot.* 



Soon after the completion of the. experiments water- 

 mains were laid in the Saarbriicken mines, which belong 

 to the Prussian State,* and later some of the large West- 

 phalian mines began to follow their example ; but very 

 little was done in this direction until after the occurrence 

 of a disastrous explosion at Carolinengliick Colliery on 

 February 17, 1898, by which 116 men were killed. 



Experiments with shots charged with gunpowder on the 

 one hand, and with brisant explosives on the other, in the 

 presence of inflammable gas and coal-dust, were begun 

 more or less simultaneously in Germany, France, and 

 other Continental countries, and in England both with 

 brisant explosives and water-cartridges, early in the 

 nineteenth decade of last century. I had the honour of 

 conducting those carried out in this country during a period 

 of several years, with the collaboration of Lord Merthyr, 

 who was a member of the Royal Commission on Accidents 

 in Mines, under the auspices of which they were made. 



As the result partly of the voluntary, partly of the legis- 

 lative, action taken in this country, it will be seen from 

 the following table that there has been a marked diminu- 

 tion in the number of deaths from explosions during the 

 last thirty years, notwithstanding the increase of more 

 than 50 per cent, in the number of men employed and in 

 the output of coal : — 



\car, or Average of Period Named. 



n J rt.„^.,t ^'*" employed Number 



P"'°'l 0"'P"' underground of deaths 



I year ... 1851 — .. — ... 321 



I ,, ... iSsa — ... — ... 264 



10 years ending 1862 — ... — ... 216 



,, ,, ,, 1872 128,680,321 ... 403,281 ... 238 

 ,, ,, ,, 1882 168,921,705 ... 461,024 ... 263 

 „ ,, ,, 1892 203,322,840 ... 588,446 ... 147 

 „ ,, ,, 1902 250,940,800 ... 747.509 ••• «04 

 9 ,, .. '911 - ••• - - 134 



^ I.e Gri.sou et ses Accidents, Extrait de la Revue G^ndrale des Sciences 

 pures et applicivKi's. No. 20, du 30 Octobre, iPqo, p._ 19. 

 * Hauptbericht der Preuxsischen Schlapwelter Commission, p. Jii (1887.) 

 5 Die Eniwickelung des Niederrhemisch-Westfalischeti Steinkohlen- 

 Bergbaues vol. ii., p. 6(1904). 



