THE NATIONAL GEOGRAPHIC MAGAZINE 



409 



tion's requirements was very little, if any, 

 larger than in peace times. Tens of thou- 

 sands of miners had left the coal fields 

 for the factories or for the battle front, 

 and with all the high wages paid, it was 

 next to impossible to maintain the army 

 of anthracite and bituminous workers at 

 peace-time strength. 



Let us go into the coal region and down 

 into the mines and see the sturdy har- 

 vesters reaping the grain of heat that 

 Nature stored up against the day when 

 the forest should find itself unable to 

 supply mankind with fuel. 



the: anthracite fields 



We will first visit the anthracite fields, 

 that wonderful region in Pennsylvania 

 which lies to the north of Reading, to the 

 south of Carbondale, east of the Susque- 

 hanna and west of the Lehigh rivers. 

 Scranton and Wilkes-Barre are the center 

 of the upper field, Hazleton of the middle 

 field, and Pottsville of the lower. 



Were all of the coal beds in this remark- 

 able region laid out in a compact body, 

 they would cover an area only twenty-two 

 miles square. Yet out of such a small 

 area have come billions of tons of coal and 

 culm, the former to cheer a million fire- 

 sides, and the latter to dot every landscape, 

 and to serve as monuments to remind us 

 of the patient toil of hundreds of thou- 

 sands of men through scores of years. 



A visit to a modern colliery is an im- 

 pressive experience. Depending on its 

 size and the labor available, it will bring 

 from one to two full trainloads of coal 

 up out of the bowels of the earth every 

 day, put the coal through the breaker, 

 where the sheep of fuel are separated 

 from the goats of slate and culm, and 

 load it into the cars ready for market. 



We shall be safe even if we do go 

 down a thousand feet into the earth and 

 roam about in an underground plantation 

 whose area may be judged by the fact 

 that there are eighty-five miles of railroad 

 track in it. The colliery superintendent, 

 a rare old Welshman who has been min- 

 ing coal for twenty years, and the district 

 engineer, a fine youngster who has had 

 his engineer degree from Lehigh, will ac- 

 company us. 



There are some things on top of the 

 ground that will be even more interesting 



to us when we go below — particularly the 

 hoisting engine and the ventilating fan, 

 for without the one we would not be able 

 to ride back to daylight, and without the 

 other we would stand a chance of being 

 "gassed" over here in peaceful America 



HOW A MINE BREATHES 



The giant fans fly around with a rim 

 speed of a mile a minute, two of them, 

 with a third in reserve for emergencies. 

 If it were not for those fans the air in 

 the mine would become so laden with gas 

 and dust that if it did not explode and 

 transform the whole mine into a charnel- 

 house, it would develop choke-damp and 

 suffocate us. These fans are to the mine 

 what the involuntary muscles of the chest 

 are to the lungs — they make it breathe. 



Every mine has two shafts — the hoist- 

 ing shaft and the air shaft. In order to 

 keep the air in the mine free enough from 

 gas to permit miners to work in safety, 

 enormous quantities of fresh air must be 

 sent down the one shaft and correspond- 

 ing quantities, gas-laden, drawn out of 

 the other. 



In America this is usually accomplished 

 by exhaust fans drawing the used air up 

 the air shaft. This type of fan tends to 

 make a vacuum at the top of the shaft, 

 and the weight of the atmosphere drives 

 the fresh air down the hoisting shaft and 

 the stale air up the other. 



If that which goes down the hoisting 

 shaft were allowed to take its natural 

 course, it would make a bee-line for the 

 air shaft and rush up into the fan-created 

 vacuum at the top. That would leave the 

 foul air in every other part of the mine 

 and accomplish no great good. 



So, means have been found to lead air 

 around a mine just as effectively as one 

 might lead a horse. By the use of doors 

 and curtains and bridges, the mining 

 superintendent is able to take the current 

 of air that rushes down the hoisting shaft 

 and make it move here and there, hither 

 and yon, into every nook and cranny of 

 the mine, driving the foul air before it as 

 it goes. It seeks out every gas pocket and 

 forces itself into every chamber. 



It may very well be imagined that a 

 mine with enough tunneling to call for 

 85 miles of railroad track needs a great 

 deal of air, and that this air, to reach 



