rock with a bucket and windlass. To-day, that shaft runs sixteen hundred feet into the earth, and tons of ore come up out of it every day. That's the shaft we're going down, Tommy, and you can see for yourself. Ever been underground before?"

"No, sir."

"A big thrill is in store for you, then! I remember the first time I went down a shaft, I was scared almost to death. But you'll soon get used to it. There's the whistlewe'll have to jump."

Together they hastened down the face of the hill toward the minehead. A little knot of miners Mexicans scantily clad and each and each carrying a package of lunch-were gathered about the mouth of the shaft. As fast as the little cage brought workmen from the depths of the earth, it was filled by men of the new shift, going down to take their places hundreds of feet below the light of day. For eight hours they would toil in the dusky tunnels, delving and picking and blasting the solid ore, that the world might have copper to use.

Tommy and his guide stood a little apart from the group, in the shadow of the hoist-house. From the cages in the shaft ran strong cables over the shaft-head to the hoist-house, where an alert Mexican stood above a huge revolving drum, pulling levers backward and forward. When he pulled the lever forward, the drum revolved and wound up the cable, pulling the cage to the surface. Down the shaft there were tunnels or "levels" every hundred feet, where men were to be taken on the car or let off; and there was, in the other half of the shaft, a constant stream of ore-cars coming up loaded and returning empty. Tommy watched the silent hoist-operator, and caught his breath, realizing how many lives depended each minute upon his quickness and skill.

Mulcahy was stooping and loading his two lamps with lumps of calcium carbide, and filling the tops with water. The bell in the hoist-house clanged again and again, and the business of changing shift was almost completed. A string of miners, their day's work done, stretched off down the cañon toward their homes in the old town.

Mulcahy straightened and lit the lamps with a sulphur match, to test them. A thin bright jet of flame spurted from each lamp. Making sure they were in good working order, he blew them out again.

"You'll learn your drilling under real mining conditions, Tommy," he promised. "Ready to go down now?"

"Sure." "Scared?" "Aw-say!"

"That's the spirit! Catorce!" The last word was shouted to the hoist-operator, and meant that they would go down to Level 14, at the bottom of the mine, fourteen hundred feet below sunlight.

The bell rang, the drum turned, the cable hummed, and the little cage appeared at the landing-place.

"Step right on our private elevator, young Dane," grinned Mulcahy, "and say good-by to the sun."

Tommy hopped briskly on the small platform. The little cage was open on all sides, but an iron roof protected the riders from chance falling rocks. It seemed a frail little chamber in which to trust one's life. He looked at the steel cable-line that held it, and wondered if it would snap asunder at any minute now.

Tommy clung to his sombrero, and held his breath in the rush of air that tore upward around the little cage. Greased lightning! The walls of raw rock around them showed only as a darker blur in the darkness.

A flash of light told that they had passed the first landing-level. An immense empty feeling made itself known in the pit of Tommy's stomach. Another flash of light, and another.

"Some joy-ride, eh?" shouted Mulcahy close to his ear. He could only nod in delirious assent.

"Scared the cable'll break?

Well,

I was the first time too, but I found out how they guard against that. There's two chunks of metal attached to the cable just above our heads. If the cable snaps, they fall out and grip the guides. They call 'em 'dogs' because they hang on so tight!"

The reckless plunge of the cage slackened a little as more lights whizzed by. In a brief while it jolted and came to a breath-taking halt. Blinding lights were in the boy's eyes, and a deafening roar in his ears.

"Level 14, last stop-all out!" cried Mulcahy.

They stepped off, and the man pulled the bell-cord again. Their little car disappeared above as rapidly as it had come, and they were left fourteen hundred feet underground.

Tommy eyed the "little box." "What about this lamp, Señor Tim?"

"Don't get it too near the box, or the dynamite will burn up. Not much danger from fire, though. That's lesson number one for you. Dynamite will burn without exploding-it goes off only by percussion."

Tommy gingerly lifted the box. He would be more than careful where dynamite was concerned.

"Adelante-forward march!" cried Mulcahy, and led the way down the drift, following the rails of the little ore-cars. The air was warm and damp, and moisture dripped from the glistening rocks overhead. The walls of the tunnel showed strains of many colors in the lamp-light; and in several places Tommy, tall for his age, had to bend his head to pass beneath the thick shoring-timbers that supported the roof.

The little party turned several corners, and walked up a slight incline. Occasionally they had to make way for a laden ore-car, pushed by a sweating laborer. The sound of picks and shovels came from a distance. Another corner, and they left the tracks behind.

Mulcahy waved a hand.

"Here we are," he said. "Here's the stope where we do our little job."

Tommy looked about, stumbled near a deep hole beside him, and almost dropped the box of dynamite in the excitement. The light from his lamp revealed a small, weathered sign-board tacked to a timber above the hole. The letters were scrawled unevenly in black paint, "BURTON." Tommy pointed to it.

"The sign-what does it mean?" he asked.

"Oh, Burton was a man who was killed here. He was a friend of mine, and I don't like to talk about it, son. Let's get on to the end of the working."

Tommy was more than glad to leave the tragic vicinity. They did not have far to go. The tunnel stopped abruptly in a few yards, and a dead wall of rock faced them. It was stained a dark green- a sign of copper salts, Tommy knew.

up every scrap of advice. He asked many questions, and all were given careful answers. He liked Mulcahy more than ever.

"All right, Antonio!" said the driller, finally. "Pronto!"

eh? Well, don't worry-not one chance in a thousand that it will happen."

The whirring drill bit into the rock, and the splinters began to fly. Antonio, shielded by goggles, directed A spot was marked, and the big the boring steel forward. drill bitted and made ready. "Stand back a ways, Tommy.

hole and stuff in the right amount of dynamite, a little tamping sand, placed just right, will send the force into the rock, instead of out the hole. Running the rock-drill is a job that needs skill and experience, too."

"Me-I have seen the men drill on the fiesta, in that big rock on the mesa," interrupted Tommy.

"Exhibition stuff. They work for speed then; in regular drilling, it's carefulness that counts most. Now, see this drill-" He took the instrument and began to explain its details slowly.

Tommy listened eagerly, storing

"One thing you won't have to worry about, when you start drilling out at your claim," remarked Mulcahy, as he directed Antonio's movements, "is having 'dead' charges. Sometimes a charge is placed but for some reason doesn't go off. For instance, this stope has been worked a lot. In the wall here there might be an unexploded charge of dynamite that we don't know about. If our drill was to run into it, nowCurtains? You said it."

Tommy looked about him. cahy smiled.

You can see just as well." Mulcahy watched the progress sharply. "We'll make three holes, trianglewise, and charge them all. Always keep your dynamite in your steel chest until you need it-then a falling rock won't set it off and-blow your hat off!"

Tommy backed off several yards. To hear such grim joking was not reassuring to any one down in the dark tunnels of the mine for the first time. The dank air weighed upon him, and the whirring drill rasped his nerves. It stopped suddenly, and the echo came winding back down the dark cavern. "Hole Number One," said Mulcahy cheerily. "Is she hot, Antonio?"

Tommy squatted on his heels and waited. A cloud of gloomy foreboding settled on his shoulders. He noted a little running stream, a mere trickle of stained water, at his side, shedding off down the stope.

At his back came a rattle and roar, that stopped with a jerk. A longdrawn, hooting call shook him about. It was a voice, calling his name.

"Hoo! Tomás, is it you, friend? What do you here, little comrade?"

He started up in surprise. A small figure was running toward him through the gloom, a Mexican lad wearing nothing but a grimy pair of trousers and a worn straw sombrero. It was a Mul- minute before he recognized him. "What do you here, Tomás, here (Continued on page 326)

"Not much chance of getting out,

THIS is often called the Age of Steel. Steel is said to be the symbol of modern power. That nation which controls it in largest quantity will dominate the industrial and commercial worlds. But why should steel be so tremendously important? Should we starve without it? Of how many necessities and comforts should we be deprived if there were no steel? Let us see.

There is scarcely a machine anywhere that is not made of steel. A steel plow, often drawn by a steel tractor, turns under the sod in the spring. A steel harrow prepares the ground. A steel drill sows the seed. Tractor-drawn reapers of steel cut the ripened grain. Threshing-machines of steel separate the wheat, barley, rye, and oats. Elevators of steel hold the grain in storage. Steel ships and trains carry it to distant markets. In scores of ways, steel is indispensable to agriculture, and without this basic industry, nations would perish. The gasoline motor of high-grade steel has become the willing burdenbearer of the farm. It pumps the water, separates the cream, saws the wood, cuts the ensilage, grinds the feed, runs the fanning-mill, generates electric current for light and power, and performs a multitude of other useful tasks. Everywhere one turns, upon a farm, he finds something made of steel. Without it, the farmer would be as helpless as the caveman with his wooden clubs and implements of stone.

But we have not begun to enumerate the uses of steel. Your automobile is nearly all steel. New discoveries in the making of steel, too, have lessened its weight by nearly a thousand pounds. Fingers of steel spin and weave the fabrics of the world. Sewing-machines of steel

stitch them into garments. Tools and cutting machines of the most durable steel remove the ores from the mines. Furnaces of steel smelt them. Steel is drawn into thousands of miles of wire and rolled into acres of sheet metal. The railroads that span the continents, the floating palaces that bridge the seas, the locomotives that laugh at time and space, the huge skyscrapers of our cities, the big guns and armor-plate of the world's proudest navies, the wonderful bridges that cross our rivers, the mighty steam turbines, dynamos, and motors of our powerplants and factories, the multitude of machines that fill the workshops of the world, and the millions of nails and bolts and nuts and screws that hold things together, all these and much besides are largely wrought of steel.

If the supply of steel were to be cut off even for a short time, industry would be paralyzed and great numbers of men would be in idleness. And steel comes close to your happiness in dozens of ways. The knife in your pocket, your skates, your hatchet,

"A GREAT SHEET OF FLAME LEAPS FROM THE CRUCIBLE'S MOUTH"

the delicate hair-spring of your watch, the tools in your shop, your electric locomotive and railroad system, your gun, your bicycle, the furnace that warms your home, and scores of other articles are made of steel. You simply could not get along without steel. Steel, too, is sometimes worth more than its weight in gold. The small balance-wheels for watches that may be made from a pound of steel are worth twenty-five thousand dollars, a much larger sum than the value of a pound of gold. In the Great War, steel was paramount. It was the stupendous output of America's thousands of furnaces more than any other material necessity that turned the tide of battle. And in the day of peace, steel is no less important. It has been estimated that the power-driven machinery of the United States performs work equivalent to that of three billion human slaves. That is, machines of steel place at the disposal of every man, woman, and child in the country the equivalent of nearly thirty hardworking servants. Yes, I think you will agree that steel is the foundation of modern industry.

A VISIT TO A STEEL PLANT COME with me and we will visit a steel plant. We shall go to Pueblo, Colorado, known as the Pittsburgh of the West, where are located the largest iron and steel furnaces beyond the Mississippi River. At one time, I taught in Pueblo and used to delight in going out to the great fiery furnaces and watching the process of changing ore from the mines into the finished products of iron and steel.

Armed with passes, we are admitted through the gates and provided with a guide. We are taken first to the blast-furnaces, for there the process

begins. Presently, we come to one, towering like a giant ninety to one hundred feet into the air, twenty to twenty-five feet in diameter, and flanked with its battery of huge "stoves" for preheating the hot blast of air blown into the bottom of the furnace. Let us fix in our minds, if we do not already know it, that every bit of iron and steel used in the manufacture of anything, from the delicate hair-spring of a watch to a giant locomotive, must come from the ore that passes through the blast-furnace. At one side of the furnace we see hoisting machinery for carrying to the top the charge of ore and other materials necessary for the production of iron. Our guide tells us that every twenty-four hours one of these furnaces swallows up 800 tons of ore, 400 tons of coke, and 100 tons of limestone, besides consuming 1200 tons of air. During this same period, it turns out 600 tons of molten pigiron, 500 tons of slag, and 1400 tons of gases. And the process never ceases. A furnace is kept in continuous operation for months and even years. The production of pig-iron in the United States for 1923, one of the largest of recent years, was 40,361,146 long tons of 2240 pounds each.

"But what is all this about ore,

fuel for the furnace. There are still other heaps of limestone rock. Into the top of the furnace we see the operator of the hoisting machinery charge successive layers of coke, ore, and limestone. Inside is a roaring fire at a temperature of more than 1100 degrees Centigrade, at the

coke, limestone, slag, and pig-iron?" I hear you say. We shall have to explain. Stepping outside the steel structure surrounding the bottom of the furnace, we see great mountains of ore, brought by trains from distant mines. The lumps are of various colors, but the ore richest in iron is a dark red. In pure form, it is pulverized to form rouge, an ordinary paint pigment. Now this ore consists of the element iron chemically combined with the element oxygen

bottom of which a powerful blast supplies air at the rate of nearly 40,000 cubic feet per minute. Something has to happen, and it does. The coke burns, forming not carbon dioxide, but carbon monoxide, a gas with a great liking for oxygen. This gas unites with the oxygen in the ore, leaving molten iron, which trickles in thousands of little rivulets to the well at the bottom of the furnace. The separation of the iron is what we wanted to accomplish. The problem

stone fuses, or melts and unites with the rock and earth, forming a molten glass called slag. Like the iron, this makes its way to the bottom of the furnace, where, being lighter than the iron, it floats upon its surface. The gases issuing from the top of the furnace are combustible. They formerly were allowed to go to waste, but now they are used to run gasengines and in the stoves, already seen, to heat the blast of air before it enters the furnace.

If our visit happens to be timed right, we shall see the "tapping off" of the molten slag and iron. We notice that the blast-furnace in this case stands near the edge of a sandbank having a vertical drop at the edge of five or six feet. At the foot of the bank runs a narrow railroad on which small engines draw up cars carrying huge kettles, called ladles, to receive the iron and slag. We watch the workmen as they make a shallow trench in the loose sand to carry the slag and iron from the foot of the furnace over to the waiting cars. Presently the upper plug of the furnace well is removed, and we see a stream of slag, really white-hot, molten rock, gush forth and, flowing to the edge of the bank, tumble like a cataract into the ladles. When all of the slag has been drawn off, the engine carries it away to be poured out to harden. Slag is sometimes used in the making of Portland cement, but it is often broken up and used as ballast in railroad construction.

An even more interesting sight is yet to come. Another car with its ladle is brought into position. The workmen remove the lower plug from

a

the furnace well. Out comes torrent of dazzling brilliancy, and we see a stream of molten iron, flowing as freely as water, slip down the trench and fall in a cascade over the edge of the bank and into the ladle. Fifteen tons of iron have been drawn off, and we see the engine steam away with it to another part of the plant. We will follow it.

As we pass along, I will tell you something about the iron made in the blast-furnace. It is called pig-iron. There is a reason for the term "pig," as we shall see later. As one would naturally expect, this first product from the ore is the most impure of any kind of iron. It contains from five to eight per cent of the elements carbon, phosphorus, sulphur, and silicon. These make the iron hard and brittle and give it a low meltingpoint. When pig-iron has been remelted, in what is called a cupola furnace, and poured into sand molds, it is called cast-iron. Unless it receives special heat treatment, it can never be forged or welded. It is used for making all sorts of castings, such as stoves and various parts of machinery.

And now we have arrived at the large steel building to which the ladle of pig-iron has been taken. Before us we see several huge egg-shaped crucibles, each about twenty feet high and nine feet in diameter. Each crucible is mounted on two projecting axles, called trunnions, one of which is hollow and is connected with a powerful blast-engine. Presently, as though it were alive, we see the crucible turn on its trunnions into a nearly horizontal position. A giant crane reaches down, and, picking up the ladle with the utmost ease, swings it to the crucible's mouth and pours into it the molten iron. Immediately, the crucible is turned into a nearly upright position. The blast-engine starts. A terrifying roar greets our ears and a great sheet of flame leaps from the crucible's mouth. Hot cinders fall about us like the patter of hail, and we wonder if the earth has not opened up in an outburst of volcanic fury. This brilliant spectacle, with its deafening roar, surpasses everything we have ever seen in the way of Fourth-of-July celebrations. But it does not last. Gradually, the flame grows smaller, then almost disappears; the tempest passes, and quiet comes again.

Again the crucible is turned into a nearly horizontal position, and we see workmen put into it several hundred pounds of a black, metallic-looking substance which our guide tells us is an alloy rich in carbon and manganese. Once more the crucible is inclined and