Iron

"O F all substances iron displays the greatest power of resistance; and it is this property that makes it the most useful of all our metals. All sorts of tools are made of it, and without it our industries would come to an immediate standstill."

"Yes, I see that iron is very useful," said Jules.

"But perhaps you do not see how useful it is. Reflect a moment and you will perceive that iron has had something to do with nearly everything in the house you live in. And at the very outset, in order that the house may be built, there is need of stone from the quarries, where picks and crowbars and chisels and hammers are in constant use, all these being, as you know, made of iron or steel. The beams and joists of the framework come from trees felled by the woodman's axe; and these timbers are squared and shaped, fitted and adjusted with the help of various carpenter's tools, all made of the metal we are considering. Hardly a single one of our articles of furniture would be practically possible without this metal: we need the saw for cutting the log into boards, the plane and the draw-knife for smoothing the surface, the auger and the bit for boring the holes that are to receive the wooden pegs which hold the parts together.

"Our daily sustenance entails the use of iron in an almost equal degree: it calls for the spade, the hoe, and the rake for working the garden which gives us our vegetables, and the plowshare for the heavy work of the field which furnishes us with bread.

"In the clothes we wear, too, we are hardly less dependent upon this indispensable substance. Of it are made the shears that clip the wool from the sheep's back, and of it also are made the carding- and spinning- and weaving-machines that convert the wool into cloth. Our most delicate fabrics, our ribbons and laces, require the aid of this metal in their manufacture; and, finally, is not the needle used in every stitch that is sewed, the needle so fine and sharp-pointed that nothing else could take its place?"

"It is plain enough," said Marie, "that iron is of the utmost importance to us, though we usually give it very little thought. It is so common that we make no account of it, in spite of the immense service it renders us."

"I should like to know how iron is obtained," Claire interposed, "if Uncle Paul will tell us."

"Iron ore," he explained, "is a yellow or reddish stone of very unpromising appearance, with no resemblance to the metal so familiar to us. The furnace in which it is worked is a sort of high tower, swollen toward the base, tapering at the two ends, and measuring at least ten meters, sometimes twenty, in height. Through the upper door or mouth of the furnace is poured coal by the cart-load, with fragments of ore, and when once lighted the furnace burns uninterruptedly, day and night, until the masonry succumbs to the intensity of the heat. Workmen are continually piling on fuel and ore as fast as there is any subsidence in the burning mass, while other workmen at the base of the furnace watch the melting of the ore. Enormous blowing-machines inject a continuous stream of air into the lower part of the furnace by a great tube, through which this current passes, not as a gentle breeze, but as a veritable tornado, raging and howling with an uproar that is fairly deafening. If one takes a peep into the furnace from the opening by which the tube enters a sort of white-hot inferno dazzles the eye. Here stones melt like butter, and iron, separating from the impurities mingled with it, falls in glowing drops into a reservoir or trough at the base of the furnace. When the trough is full a passage is opened by the removal of the clay stopper that closed it, and the liquid metal runs in a fiery stream into channels prepared for it in the ground.

"The metal thus obtained is impure iron and is known as cast-iron. It is run into molds to make stoves, grates, pots, and kettles, chimney-plates, water-pipes, and countless other objects. Although of great hardness, cast-iron is brittle: it breaks easily when sharply struck."

"One day," said Emile, "a stove-cover broke into three pieces just from falling on the floor."

"It is well to bear in mind," his uncle observed, "that all our cast-iron implements are more or less fragile, and that it takes but a blow or a fall to break them."

"Then," remarked Claire, "cast-iron won't do for making anything that must resist violent shocks—hammers, for instance."

"No, cast-iron is worthless for tools that are subject to rough handling; pure iron alone has the necessary resisting power. To purify cast-iron and convert it into wrought-iron, the workers heat it in still another furnace; and when it has become quite red and soft it is hammered with a block weighing some thousands of kilograms, and which is raised by machinery and then falls with all its weight. At each blow from this enormous hammer what is not iron escapes from the rest and runs off in a sweat of fire.

"After this hammering the mass is grasped between two cylinders, one above the other, turning in opposite directions. Dragged along by this powerful wringing-machine and flattened out by the irresistible pressure, it becomes in a very short time a uniform bar of iron. Shears next take hold of the bar and cut it up into pieces of equal length."

"What! Are there shears that can cut iron bars?" exclaimed Claire.

"Yes, my child; in those wonderful factories where human invention is brought to bear on the working of iron there are shears that without the least appearance of effort cut clean through a bar of iron with each snip, no matter if the bar be as big around as a man's leg. With our scissors we could not more easily cut a straw."

"But such shears cannot be operated by hand?"

"Nor are the two blades moved at the same time. While one of them remains at rest on a support, the other goes up and down as calmly and noiselessly as you please, cutting with each downward stroke the bar of iron offered it by a workman."