226 
COLLIEKY EXPLOSIONS. 
plain, therefore, that, in the latter case, the ventilating current 
must either obtain an additional supply of moisture from the 
workings (about half pound for every 100 cubic feet of air), or it 
must be drier than in the former case at every point of its 
course.” 
“ Prima facie, then, this process of reasoning leads us to 
the conclusion that explosions, whose magnitude is due to the in- 
fluence of coal dust, will happen most frequently during cold 
weather ; and conversely, we might expect to find that th(* 
magnitude of these explosions which occur during cold weather 
is traceable, in some measure, to the influence of coal dust.” 
As to the practice of blasting in mines, there seems to 
be no doubt that the flash of the powder has been the im- 
mediate cause of explosions. This being the case, the abolishing 
of such modes of working has been advocated. To those familai'^ 
with mining operations the difficulties which would be occasioned 
are at once apparent, and the ordinary reader can also form some 
idea of the disadvantages under which the miner would labour. 
If it were simplj^ a matter of blasting the coal, the objection to 
the doing away with it would not be so great, but it is in 
making the roads and in general repairs that the use of power is 
required more especially. It seems to me that if Mr. Gallaway's 
recommendation of watering the neighbourhood where blasting is 
to take place (just before the shot is fired), were carried out, 
there would not be much to fear, provided, of course, that the 
lamps did not indicate the presence of gas. 
