38 rEeport—1890. 
tion of new explosive agents for mining and quarrying purposes, which 
present or lay claim to points of superiority over the well-established 
biasting-agents, has been by no means at a standstill. For many years 
the main object sought to be achieved in this direction was to surpass, 
in power or adaptability to particular classes of work, the well-known 
preparations of nitro-glycerine and gun-cotton, which, during the past 
twenty years, have been formidable competitors and, in many directions, 
absolutely successful rivals of black powder. It is both interesting and 
satisfactory to note, however, that this object has of late, and especially 
since the publication of the results of labours of English and foreign 
Commissions on the causes of mine-accidents, been prominently associated 
with endeavours to solve the important problems of combining, in an 
explosive agent, efficiency in point of power with comparative non- 
sensitiveness to explosion by friction or percussion, and of securing 
its effective operation with little or no accompaniment of projected flame. 
Safety-dynamites, flameless explosives, water-cartridges, and other classes 
of materials and devices connected with the getting of coal, the quarry- 
ing of rock, or the blasting of minerals, have claimed the attention of 
those who guide the miner’s work; in some of these directions the 
practical results obtained have been beyond question important, and, 
indeed, conclusive as regards the great diminution of risks to which 
men need be exposed in those coal-mines where the ordinary use of 
explosives, although not altogether inadmissible, may at times be attended 
with danger. It is to be feared that those results are still far from 
receiving the amount of application which might reasonably be hoped 
for; but, at any rate, there are, among the extensive mining districts 
where the employment of explosives in connection with the getting of coal 
cannot be dispensed with, several of importance where the use of gun- 
powder has almost entirely given place to the adoption of blasting-agents 
or methods of blasting, the employment of which is either not, or only 
very exceptionally, attended by the projection of flame or incandescent 
matter into the air where the shot is fired. 
The mining public is especially indebted to German workers for much 
of the success which has been obtained in this direction, and also to the emi- 
nent French authorities, Mallard and Le Chatelier, for their thorough theo- 
retical and practical investigations bearing upon the prevention of acci- 
dental ignition of fire-damp during blasting operations. Having arrived at 
the conclusion that fire-damp- and air-mixtures are not ignited by the firing 
of explosive preparations which develop by their detonation temperatures 
lower than 2220° C., they found that ammonium-nitrate, although in 
itself susceptible of detonation, does not develop a higher temperature than 
1180° C., while the temperature of detonation of nitro-glycerine and gun- 
cotton are, respectively, 3170° and 2636°. Hence the admixture of that 
salt with nitro-glycerine or gun-cotton in sufficient proportion to reduce 
the temperature of detonation to within safe limits should allow of the 
