Scenes And Incidents From The Life Of A Practical Miner
With A Treatise On The Ventilation Of Coal Mines

47 along on the east side of the tramway you see the common pressure of the atmosphere is acting on every man while at work, and in leaving the last man, it then, and only then, enters the waste or back workings, when it is conveyed through it by the wastemen. In entering the waste to east, it passes through an aperture, a regulating slide giving sufficient area to admit compression without obstruction. We now leave this whole working district, satisfied with what we have seen, and in returning, come to a broken or pillar working district to the south, ventilated with the same cun-ent of air after its leaving the waste and crossing over the horseway by the arch, where we stopped at forty yards up, when going in. On entering it, we have to pass through two double doors, set to a frame, quite, air tight, with “snecks” on each, and a sufficient distance from each other to admit the set to pass through one before the other is required to be opened. When at the first door, we prepare our safety lamps, and leave our candles. Thus wo proceed on. our inspection. After passing through the inner door we find ourselves entering into a dull, drowsy atmosphere, which evi- dently denotes a serious innovation on the general current of air, and shows to our view the eruptions of nature in the mine which is sending forth its gases and noxious effluvium, its acids and oxides, and the respiration of perhaps 250 men, boys, and horses. The effect of all these causes is that the air has lost the cheering vitality of the oxygen. The affinity of the latter to these mineral bodies, by causing them to unite, have destroyed all the former elasticity of the atmosphere, which lias become now by this chemical process of nature a. fluid body quite different in its character, and which must, therefore, be treated by laws suitable to its present organization. In a proper system of ventilation the aim is to give it space and ample area in the passages it has to return in from the interior of the mine, according to and in unison with its bulk of matter. For he it understood those gasses generated by the different strata in the mine, whether they be as an aeriform gas or a vapour fluid, have their solid particles, and cannot be compressed without friction, which immediately becomes an obstruction to the general current of air. Consequently, in an extensive mine, as tins is, with four or five working districts, each aired with a divisional split from the general volume of air, there should not be less than four drifts for the air to return back in, and each of these drifts should contain, from thirty to foi’ty feet area to be equivalent to the in- going drift. For instance, from the accumulated mass of matter gene- rated throughout the whole extent of the mine, it must be obvious to the practical observer, who has carefully studied the elements of nature, that carbonic acid will, nay must, be the predominant portion of the returning volume of air, inasmuch as it exists in union with earth and stone in vast quantities, however far they may be hid from the surface of the atmospheric boundary. This alone may tell us in indisputable language the vast increase of area required to permit the returning volume composed of such material to glide through its passages without obstruction, back to the furnace and upcast pit. As I have in a foi'mer part of this treatise described with scientific care the instantaneous resus-