tremendous quantity of gas is set free, which may be sufficient to foul the passages for some distance around.  The introduction or exposure of a naked light for even so much as a second is sufficient to cause explosion of the mass; doors are blown down, props and tubbing are charred up, and the volume of smoke, rushing up by the nearest shaft and overthrowing the engine-house and other structures at the mouth, conveys its own sad message to those at the surface, of the dreadful catastrophe that has happened below.  Perhaps all that remains of some of the workers consists of charred and scorched bodies, scarcely recognisable as human beings.  Others escape with scorched arms or legs, and singed hair, to tell the terrible tale to those who were more fortunately absent; to speak of their own sufferings when, after having escaped the worst effects of the explosion, they encountered the asphyxiating rush of the after-damp or choke-damp, which had been caused by the combustion of the fire-damp.  “Choke-damp” in very truth it is, for it is principally composed of our old acquaintance carbonic acid gas (carbon dioxide), which is well known as a non-supporter of combustion and as an asphyxiator of animal life.

It seems a terrible thing that on occasions the workings and walls themselves of a coal-mine catch fire and burn incessantly.  Yet such is the case.  Years ago this happened in the case of an old colliery near Dudley, at the surface of which, by means of the heat and steam thus afforded, early potatoes for the London market, we are told, were grown; and it was no unusual thing to see the smoke emerging from cracks and crevices in the rocks in the vicinity of the town.

From fire on the one hand, we pass, on the other, to the danger which awaits miners from a sudden inrush of water.  During the great coal strike of 1893, certain mines became unworkable in consequence of the quantity of water which flooded the mines, and which, continually passing along the natural fractures in the earth’s crust, is always ready to find a storage reservoir in the workings of a coal-mine.  This is a difficulty which is always experienced in the sinking of shafts, and the shutting off of water engages the best efforts of mining engineers.

Added to these various dangers which exist in the coal-mine, we must not omit to notice those accidents that are continually being caused by the falling-in of roofs or of walls, from the falling of insecure timber, or of what are known as “coal-pipes” or “bell-moulds.”  Then, again, every man that enters the mine trusts his life to the cage by which he descends to his labour, and shaft accidents are not infrequent.

The following table shows the number of deaths from colliery accidents for a period of ten years, compiled by a Government inspector, and from this it will be seen that those resulting from falling roofs number considerably more than one-third of the whole.