THE NATIONAL GEOGRAPHIC MAGAZINE 



419 



causts ; but as the years go by greater 

 care is used, better ventilation is main- 

 tained, and the disasters, happily, are 

 growing fewer. 



After-damp is one of the deadliest of 

 all gases encountered in mines, but fortu- 

 nately it does not occur except following 

 fires. It is so subtle that the miner is 

 powerless to escape its attack when he 

 realizes its presence. Odorless, or pos- 

 sessed of a mere hint of violet, its victims 

 experience an exhilaration at its onset 

 that seems to them only a sensation of 

 feeling unusually well ; but so quick and 

 deadly are its effects that before this feel- 

 ing passes, the victim is wholly within its 

 grasp. 



HAND METHODS PRODUCE ANTHRACITE 



In the anthracite region mining is still 

 done principally by hand. Some jack- 

 hammer drills have been introduced and 

 some electric coal-cutting machines ; but 

 hand methods still produce most of the 

 anthracite. The jack-hammer drill is an 

 instrument which bores the blast-holes by 

 power. With one of these drills a miner 

 is enabled to bore as many holes in one 

 hour as he can bore in eighteen with a 

 hand-drill. Among the illustrations of 

 this article (see pages 414 and 416) will 

 be found pictures of cutting machines, 

 jack-hammer drills, mechanical shovelers, 

 etc. — labor-saving machinery that is now 

 working wonders in the productive pow- 

 ers of the miners. 



If space permitted we would follow our 

 fine old Welsh guide up into the "kidney" 

 of the mine and see a second layout of 

 entries, headings, and chambers in a half- 

 way station seam ; we would contrast the 

 new steel timbering of the mines with the 

 old wood timbers coming from the South ; 

 we would stop to look at the mule stables, 

 as clean and as sanitary as any stables 

 you ever saw, with a sand-floored yard, 

 where the sick ones may roll and rest to 

 their hearts' content. 



But let us follow the coal up the shaft, 

 and through the breaker in the case of 

 anthracite, and through the tipple or 

 dumping house in the case of bituminous. 



When we reach the top again, we note 

 the layout of the breaker plant, where 

 the coal is cleaned and sorted into the sev- 

 eral commercial sizes. The first thing 



that impresses us is that the mine-owners 

 are almost as careful in saving coal as a 

 miser is in hoarding his gold. 



The loaded mine cars are rolled off the 

 cage by hand, and the breaker building is 

 so situated that the cars run down to it by 

 gravity. As the cars roll down to the 

 breaker hoist, which may be either a verti- 

 cal lift or an inclined plane, boys "sprag" 

 or "scotch 1 ' them and let them down to 

 the hoist one by one. 



Going up to the top of the breaker, we 

 see the coal as it comes from the mine, 

 with all its slate and culm, mechanically 

 dumped, a carload at a time, upon the 

 oscillating bars, which begin the process 

 of separating the coal from the worthless 

 material and the assorting of the former 

 into groups according to size. 



There are eight different sizes of coal 

 now in general use — broken, egg, stove, 

 and chestnut, which are the domestic 

 sizes, and pea, buckwheat, rice, and bar- 

 ley, which are steaming coals. They 

 range from four inches in diameter for 

 broken to one-sixteenth of an inch for 

 barley. Of course, there are as many 

 pockets at the railroad tracks as there are 

 grades of coal produced in a breaker, and 

 as many chutes into the cars as are neces- 

 sary to load every grade simultaneously. 



After the "bony" coal passes through 

 the crushers and is broken up, it joins the 

 procession of unseparated slate and coal 

 down the several chutes. At one place it 

 runs through a centrifugal slate picker, 

 which is a striking contrivance that does 

 the work of a jig in another type of 

 breaker. 



There are dry breakers and wet ones, 

 but this has no reference to the presence 

 or absence of prohibition. Dry breakers 

 are those where the coal comes from the 

 mine fairly clean and goes through the 

 breaker without being watered, either for 

 the suppression of dust or for the wash- 

 ing of the coal. 



Also, there are breakers which sepa- 

 rate the slate and culm from the coal by 

 jigs rather than by centrifugal pickers. 

 In these the coal as it comes from the 

 mine is " jigged" up and down in water. 

 The coal settles more slowly than the 

 slate and culm and can therefore be 

 skimmed off like cream from milk. 



In order that the miners may not be 



