A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE 



'* To the solid ground 

 Of Nature trusts the mind which builds for aye." — WORDSWORTH 



THURSDAY, NOVEMBER 4, li 



EXPLOSIONS IN COAL-MINES 

 Explosions in Coal-Mines. By W. N. and J. B.Atkinson, 

 H.M. Inspectors of Mines. (London : Longmans, 

 1886.) 



I]*VERYBODY in the least degree conversant with 

 -' matters connected with coal-mining will at once 

 admit that our knowledge of the remote causes of colliery 

 explosions has increased enormously during the last few- 

 years. Whether, however, the practical application of 

 this knowledge has kept pace with the rate of increase in 

 the knowledge itself is another matter. Since 1851, when 

 the first Mines Inspection Act was in force, the number 

 of fatal explosions in collieries has steadily diminished, 

 but the annual loss of life from these catastrophes is as 

 great as ever. During the ten years ending i860 there 

 were 820 fatal explosions, resulting in 2441 deaths, or an 

 average of 2'9S deaths per fatal explosion ; during this 

 decade there was an average of 3000 persons employed 

 in and about the mines for every fatal explosion, and 1008 

 persons for each resulting death. During the ten years 

 ending 1870 the number of fatal explosions fell to 565 ; 

 the deaths were 2267, or an average of 4'oi per fatal 

 explosion ; and the ratio of persons employed to each 

 fatal explosion w-as 5650, and hence to each resulting 

 death 1408. During the ten years ending 1880 the 

 number of fatal explosions was 424 ; the resulting deaths 

 were 26S6, or an average of 6'33 per fata! explosion ; the 

 ratio of persons employed to each fatal explosion was 

 11,372, and to each resulting death 1795. During the five 

 years ending 1885 we have had 146 fatal explosions, with 

 a loss of 906 persons, or an average of 5'2o deaths from 

 each explosion ; the ratio of persons employed to each 

 fatal explosion was 17,503, and to each resulting death 

 2820. These figures are in the highest degree significant, 

 but they are not capable of telling everything. They do 

 not, for example, bring out the fact that the actual violence 

 of colliery explosions when they do occur is nowadays 

 greater than formerly. This may seem to be indicated 

 by the increase in the average number of deaths from 

 Vol. XXXV.— No. 888 



each fatal explosion, but then, on the other hand, there 

 are far more men employed in pits now than formerly. 

 The diminished number of explosions is probably due, in 

 the first instance, to the more general employment of 

 safety-lamps, and, during late years, to the restrictions 

 which have been placed upon the use of explosives. The 

 increase in the average number of deaths to each 

 explosion is doubtless owing to the gradual deepening of 

 the pits and to differences in the mode of origin and 

 character of the explosion. Thirty years ago the pits as 

 a rule were comparatively shallow and damp. Such a 

 sinking as that of the Ashton AIoss pit at Audenshaw, 

 which is upwards of half a mile deep, was unknown. 

 E.xplosions in these damp shallow pits were usually 

 caused by the ignition of gas, most frequently by naked 

 lights ; they were very local in their action, and the loss 

 of life was small. Nowadays an explosion in a deep and 

 dry mine not unfrequently penetrates throughout the 

 whole pit ; it is often extremely violent, and the number 

 of deaths, mainly from after-damp, is correspondingly 

 great. 



There can be very little doubt that such explosions are, 

 in the main, caused by dust. The fact that fire-damp is 

 not the only explosive agent which may be present in 

 coal-mines is now generally recognised. It is, however, 

 a moot point with many practical men whether coal-dust 

 alone, in the entire absence of gas, can bring about an 

 explosion of any magnitude. It is generally conceded 

 that a very small amount of gas, an amount, indeed, too 

 small to be recognised by the elongation of the flarae of 

 a safety-lamp, or the form ition of a " cap," is sufficient in 

 the presence of coal-dust to form a dangerously explosive 

 atmosphere, but colliery managers and many mining 

 engineers have, apparently, been slow to believe that dust 

 itself may, under certain conditions, effect an explosion 

 quite as violent in its character as the most formidable 

 gas explosion of which we have any record. The Royal 

 Commissioners appointed to inquire into accidents in 

 mines reported that in their opinion it was well estab- 

 lished that even when the air is quite free from fire-damp, 

 an exceptionally inflaaimable coal-dust, in a very finely- 

 divided and dry condition, and existing in abundance in 

 the immediate vicinity of a blown-out shot, may when 



