"Danger! You're plumb crazy about danger, Clem!" Anton declared impatiently.

The older lad gestured to the big building of the pit-mouth before them, above which the spider-like legs of the headgear soared high, surmounted by the huge double winding-wheels which give so characteristic a note to a modern colliery.

"Any one who forgets that a coal-mine is dangerous is a fool," he retorted sharply, "and keep that in your head, Anton, my lad. Not that danger would ever stop me from mining. I like it. I like to feel that I'm running a risk every time I go into an entry and every time there's a blast. And I like to feel that I know enough about safety methods to snap my fingers at the risk. There's excitement in that."

"There'll be excitement enough, if old Otto's warnings come true," returned Anton gloomily.

Two days had passed since the old miner's prophecy, two days without any unusual incident. Clem had all but forgotten the evil presage, but Anton was brooding over it. It was his work to load cars in the room where Clem was mining, and the boy's superstitious nature made him painfully aware that if any accident happened to his comrade, he would probably be caught, too.

Anton had been working in the mine only a few weeks and he had not yet been able to grasp the need of Clem's incessant teaching with regard to the extreme prudence needed in colliery work. He had almost caused a serious accident during his first week by not blocking his car properly. The half-loaded car had begun to move down the slope of the mine gallery, it might easily have run clear down into the entry and possibly killed some one if Clem had not dashed forward and checked the car before it had too much speed.

In general, Anton had not reasoned much about the danger or the lack of danger in coal-mining. He regarded the pit as a matter of course. It was the only life he knew. All his comrades were at work in the mine or would be at work therein, as soon as their school-days were over. The boy himself had started early, soon after his father's death, since it was the only employment to be got in the neighborhood and he had his widowed mother to support.

Clem had found a place in the mine for his friend without any difficulty, for Anton was powerfully muscled. In this he took after his father, who had been almost a Hercules and one of the champion wrestlers of the mine. Born of miner stock on both sides, Anton was short and squat, able to shovel coal all day without fatigue. He had accordingly, been taken on as a loader, Clem undertaking to keep an eye over him.

It took the older lad all his time to do so. Anton was absolutely reckless by nature, and, though he was constantly being advised as to the necessary precautions for making mining safe, he could never be persuaded to adopt them.

Instead of blocking his car with one log placed across the track and another under the car and resting on the transverse log, he would put a piece of coal under the wheel and trust to its staying there; he would wear his coat loosely, over his trousers, though he was told over and over again that he ran the risk of his coat being caught by the cars, when switching, and being dragged along the side of the rib: on another occasion, Clem found the boy starting along the haulage-way used for the coal cars instead of using the man-way reserved for the workers, in order to save a couple of minutes' time.

What exasperated Clem even more was that, since Otto's warning, Anton had become more careless than ever. It was evident that the fatalistic streak in the boy made him feel that if he were foredoomed to an accident, there was no use in trying to prevent it.

The boy's impatient exclamation and his comrade's retort about danger had occurred while they were in line in front of the lamp shack, waiting to get their safety-lamps before going down for the day shift.

As in most well-organized collieries, the safety-lamps were filled and adjusted by experts, who looked after nothing else. After the lamps were lighted, they were locked—and not one of the miners was allowed a key. Thus the lamps could not be opened below ground and there was no chance for a reckless man to expose a naked flame in a room or entry where there might chance to be gas. A safety-lamp would not go out unless the air in the mine was so vitiated that it was dangerous to life to remain therein, or unless there was some defect in the lamp which would render it perilous to use.

After the lamps had been given out, Clem and Anton got in the cage to go down the shaft. Otto happened to be descending at the same time.

"We're still waiting for your 'knockers' to show themselves!" Clem suggested jestingly.

The old man deigned no reply. Instead, he looked round the cage meaningly at the other men there, most of whom frowned at Clem's remark. Among miners, it is believed to bring bad luck to speak or even to hint of accidents when in the cage. Only Otto's personal liking for the young fellow kept him from a retort which might have brought on a quarrel.

On reaching the bottom, Clem and Anton set out along the man-way together. It was a walk of nearly a mile underground from the main shaft of the mine to the distant "room" or square hole in the seam, where Clem was to dig away the coal face, and which was one of the rooms from which Anton was loading coal.

This Ohio colliery was being worked on what is known as the pillar-and-room method. This consists in dividing the seam of coal into squares like a chessboard, taking out the coal from each alternate square, leaving the intervening squares of coal intact to act as pillars in holding up the roof. They do not look like pillars to a careless observer, often being blocks of coal thirty yards square.

"It seems silly," said Anton, after they had walked on a minute or two, "to leave all this coal near the shaft and to go digging a mile away. Why not take all the coal that is handy first?"

"And have the roof come down and block up all the coal that is beyond? That would be just throwing away the wealth of the mine."

"Timber the roof, then!"

"It would cost too much, for one thing," Clem explained, "and, for another, all the timber in the world won't hold up a roof if the excavation is made too big. There's millions of tons of rock pressing down on a mine roof. Judging by the way you talk, Anton, I don't believe you understand what a coal formation is, yet."

"Isn't it like Otto said, then?"

"Only in a way. Otto's description of the coal forests was near enough—in spite of his ideas about goblins and sprites—and he was correct in saying that the forests decayed under water and turned into coal after they were pressed down by rock. But it wasn't the Flood that did that, at least not the Flood that Otto was speaking of. The coal forests existed millions of years before Noah.

"What's more, it wasn't only just once that the forests were covered by a deluge. That happened several times, a hundred or more, in some places.

"For centuries at a time, these gloomy and steaming forests grew in boggy land, only a few inches above the level of the sea. Gradually the land sank, the sea came in, the trees fell and decayed under the water, and a layer of mud or sand was deposited over them. Then gradually the land rose again just above the level of the sea, and a new forest grew. Once more the land sank below the water, the second forest fell into decay and upon that layer a new deposit of mud or sand was laid. That gave two layers or seams of coal-forest-bog, to be turned later into coal by pressure; and two layers or strata of mud or sand, to be turned into shale and slate or into sandstone, also by pressure.

"When a long time elapsed between the swampings, several centuries of coal forests had made a deep bed of bog, which, ages after, became a thick seam of coal. When the swampings happened close together, the layer of bog was shallow, producing a thin seam of coal. In the same way, the layers of shale or sandstone are thick or thin according to the length of time that the land was under the water.

"Because of that, Anton, in nearly every colliery there is not just one layer or seam of coal, but a number of them. There are sixteen different seams in this mine, showing that the land rose and fell sixteen times, probably in the course of a million years.

"Some mines show much bigger changes. In the famous coal basin of Mons, in Belgium, there are 157 layers of coal, of which 120 are thick enough to be workable. The Saar basin, on the left bank of the Rhine, which has played so important a part in the international troubles following the end of the World War, has 164 seams, with 77 of them workable, giving a thickness of 240 feet of coal. However, as the lowest layers are nearly four miles deep, they will probably never be worked."

"Why not?"

"To start with, the cost of haulage to the top would be enormous. But, aside from that, a good many mining engineers figure that the temperature at that depth would be above boiling point. You know, in general, the farther you go down in a mine, the hotter it gets."

"What do you mean by a seam being 'workable'?" the boy queried. "Can't all coal be dug out?"

"Not by a long shot. At least not so as to be worked at a profit. Suppose a seam of coal is only a few inches thick, how is a miner going to dig it out? He couldn't crawl in such a seam, let alone using his tools there."

"He could cut out enough rock at the top and bottom to give him a chance to get in."

"A miner is paid for digging coal, not digging rock," was the answer. "What's more, according to your scheme, so much shale or sandstone would be mixed with the coal that it would be useless for burning.

"Even seams two feet thick are so hard to work that most of them are left alone, and a seam three feet thick means extra expense in getting out the coal because of the difficulty of labor in hewing and transporting the coal from the face to the shaft. The ideal thickness is between six and eight feet, where a man can stand upright and can reach to the roof with a slate bar. That height, too, makes timbering easy.

"Very thick seams have their own difficulties. The worst of these is the supporting of the roof. Take a seam 30 or 40 feet thick, for example. Look at the size of the hole that is left when the coal is dug away! Timbering becomes a real problem, there, for the longer a prop is, Anton, the weaker it is. Coal managers in mines like those have to do some careful figuring, or the cost of the timber they put into the mine would be more than the value of the coal they take out."

"How do they handle it then?"

"As if it were a quarry, rather than a mine. The seam is worked on successive levels, but, even then, it is impossible to prevent constant accidents from the fall of coal or the sudden collapse of a roof. Take it the world over, and ten miners are killed every day in collieries alone. I told you coal mining was dangerous."

"But are there any of those thick seams in the United States?"

"None of the really thick ones. There's a 40-foot anthracite seam in Pennsylvania. But in France, near the famous Creusot works, there's a bed of coal which is 130 feet thick. It's a basin, though, rather than a seam.

"So you see, Anton, every coal mine is different, with its layers or seams of coal of different thicknesses and at varying distances apart. Some pits are near the surface, some are very deep; some coal is full of gas, other has very little; some coal is so hard that every bit of it has to be blasted, in other mines the coal is so soft that the hewer spends half his time spragging the face so that the coal doesn't fall on him when he's undercutting or holing. Don't you make the mistake of thinking that all a miner has to do is to use his pick! He's got to know his business thoroughly or he's useless to the mine boss and a danger to all his fellow-workmen.

"And that isn't all, Anton, not by a good deal!

"Coal mining might be bad enough, even if the coal seams always ran level. But it's very seldom that they do. They run up-hill and down-hill in all sorts of fashions and play hide-and-go-seek in a way that's fairly bewildering.

"Nearly all coal seams are broken up by faults. The coal suddenly seems to stop, and, when you go to hewing it the pick suddenly hits against a rock wall, right on the level of the seam. In the North Gallery of this very mine, there's a fault like that. You know where the 'snagger' is?"

"Sure," agreed Anton, "you mean where the cars have to be hitched on to a chain?"

"Yes, there! The coal seam jumps upwards fifty feet. That's why the cars, after rolling down nearly a quarter of a mile, by gravity, have to be pulled up fifty feet by an endless chain, to rejoin the same seam and then to go rolling on down by themselves."

"Just what are faults?"

"H'm, that's a bit hard to explain to you, Anton, because you don't know anything about geology, but maybe I can get you to see. Faults are breaks in the layers of rock, or in the stratification, as it is called. All coal seams and the rocks above and below them have been laid down by water. Since water levels everything, these layers of rock were level, once.

"In ages past, however, the crust of the earth changed a good deal. As the crust cooled, it contracted, crumpling up these different layers into all sorts of shapes. Sometimes it bulged them up, sometimes it hollowed them down so that the edges rose. Quite often a layer of rock would be cracked right across, and one half would stay level while the other shot up almost a right angle. A good many mountains show the result of this, and if you look at such rocks as are sticking up out of the ground you will see some of them standing right on edge. Once in a while, part of the broken crust slid over the other part. Then, too, though the surface may not always show it, there have been breaks in the strata below, and at the break, the layer has sunk or risen quite a distance from its former level.

"If that happens to a coal seam, you can see that where the seam breaks, suddenly, the rest of it will continue on another level, perhaps only a few feet higher or lower, perhaps a good deal more. It's up to the mine geologist to find where the coal has gone to, and it's the business of the mine engineer to remodel the entire system of working the mine in order to get at that seam."

"And are all coal mines mixed up in that funny way?" Anton queried.

"Most of them. Oh, there's no end to the tricks a coal seam can play. A deep coal seam may split into two narrow ones, too thin to work. The whole seam may quickly dwindle away to nothing, showing that, in ages past, a river came rolling over it and washed away all the forest bog. Sometimes, especially with the lowermost seams, the forest grew on rolling land, so that the bottom of the coal seam is irregular, causing all sorts of trouble in laying rails for the cars to roll on. Sometimes the layer of rock under a coal seam is so soft that when you start to timber it, the timbers sink into the floor and the roof comes toppling down.

"Among the queerest of all the things a mine geologist strikes are what are called dykes. These are great shafts of igneous rock, which were thrust up from the interior of the earth in a white-hot state and which burned away the coal as they rose. They put a dead stop to a working. I could tell you a dozen more freak things that a coal seam can do. A mine geologist has not only a new problem to tackle with every mine, but, often, with every mine gallery."

"Is that what you're studying to be, Clem?"

"No, indeed!" The young fellow's answer was emphatic. "That's 'way out of my reach. It takes a college man, with special technical training and a big experience, to be anything of a mine geologist. All I'm trying to do is to learn enough about it so that when I get to be a mine boss—if I ever do—I'll know what my chiefs are trying to do and I'll be able to help them.

"Take Otto, for example. There isn't a better worker in the mine. He gets out more coal and less broken stuff than any other man below ground. But he'll never be anything but a hewer, because he doesn't want to learn. Why, just the other day, he was growling because the mine was shut down to repair one of the shafts, though the other shaft was working all right."

"So were a lot of the men," Anton put in. "Why couldn't they go on working, with one shaft?"

"Against the law," was the crisp answer. "That's the ABC of mining. And I'll show you why! All mines are required to have two shafts, in case of accident. That law was passed because of a famous disaster that happened in England nearly a hundred years ago.

"In those days, colliers had only one shaft. One day, the beam of an engine which was directly over a shaft snapped, and a huge piece of machinery, weighing several tons, tumbled into the shaft and stuck, not far from the bottom. As it fell, it ripped away the planking which lined the shaft and a whole lot of loose rock and earth fell on top of the piece of machinery, blocking up the shaft entirely and stopping any air from passing. There were over two hundred men and boys at work below ground.

Miners Descending a Shaft.

From an Old Print.