The Wonder Book Of Knowledge Part 10

[Ill.u.s.tration: a.s.sEMBLING REPEATING SHOTGUNS AND RIFLES]

Making Barrels.

One of the most important features is, of course, the making of barrels.

The machines for drilling and boring are the best that money can buy, and the operatives the most skilful to be found anywhere. Care at this stage reduces the necessity for straightening later. Every point is given the minutest attention. In drilling 22-calibers, for example, the length of the hole must be from 100 to 125 times the diameter of the drill.

Improvements have made it possible to drill harder steel than formerly.

This reduces the weight of the gun, and is important to the man who carries it.

Taking off 2/1000 of an Inch.

The boring is an especially delicate task. In choke-boring your shotgun, for example, the final reamer took off only 2/1000 of an inch. Think of such a gossamer thread of metal! But it insures accuracy. No pains can be too great for that.

This exquisite painstaking will be seen still more in the barrel-inspection department, to which we will go now. In pa.s.sing, we must not forget the grinding shop, where is, perhaps, the finest battery of grinding machines in the United States; or the polishers running at the dizzy speed of 1,500 to 1,700 revolutions per minute and making the inside of the barrel s.h.i.+ne like gla.s.s. This high polish is important, for it resists rust and prevents leading.

[Ill.u.s.tration: SHOOTING ROOM OF BALLISTIC DEPARTMENT*

* The bullet breaks a metal tape at the moment of leaving the muzzle. This time and the time of striking target are electrically recorded on the Chronograph.]

[Ill.u.s.tration: SOME OF THE SHOOTING TESTS]

[Ill.u.s.tration: CHRONOGRAPH FOR MEASURING VELOCITIES]

[Ill.u.s.tration: WEIGHING BULLETS]

That is the atmosphere of the whole place. Every action has its reason.

There is not an unnecessary motion made by any one, and there is not one necessary thing omitted, whatever the cost or trouble.

[Ill.u.s.tration: BORING GUN BARRELS

_Courtesy of the Winchester Repeating Arms Co._]

The Making of Ammunition Today.

It is no easy matter to secure a pa.s.s to the Bridgeport plant. Its great advantage over other concerns lies, to a large degree, in the exclusive machinery that has been developed at so much pains and expense and the secrets of which are so carefully guarded. In our case, however, there will be nothing to hinder us from getting a few general impressions, provided we do not go into mechanical details too closely.

The very size of the great manufactory is impressive--sixteen acres of floor s.p.a.ce, crowded with machinery and resounding with activity. In building after building, floor above floor, the sight is similar: the long rows of busy machines, the whirling network of shafts and belts above, the intent operatives, and the steady clicking of innumerable parts blended into a softened widespread sound. It seems absolutely endless; it is a matter of hours to go through the plant. Stop at one of the machines and see the speed and accuracy with which it turns out its product; then calculate the entire number of machines and you will begin to gain a little idea as to what the total output of this vast inst.i.tution must be.

[Ill.u.s.tration: PUTTING METAL HEADS ON PAPER SHOT Sh.e.l.lS]

More than once you will find yourself wondering whether there can be guns enough in the world, or fingers enough to press their triggers, to use such a tremendous production of ammunition. But there are, and the demand is steadily increasing. This old world is a pretty big place after all.

[Ill.u.s.tration: a.s.sEMBLING AUTO SHOTGUNS]

[Ill.u.s.tration: EXAMINING PAPER Sh.e.l.lS]

[Ill.u.s.tration: REPEATING SHOTGUN MACHINING DEPARTMENT]

[Ill.u.s.tration: INSPECTING METALLIC Sh.e.l.lS]

Handling Deadly Explosives.

Operatives, girls in many cases, handle the most terrible compounds. We stop, for example, where they are making primers to go in the head of your loaded sh.e.l.l, in order that it may not miss fire when the bunch of quail whirrs suddenly into the air from the sheltering gra.s.ses. That grayish, pasty ma.s.s is wet fulminate of mercury. Suppose it should dry a trifle too rapidly. It would be the last thing you ever did suppose, for there is force enough in that double handful to blow its surroundings into fragments. You edge away a little, and no wonder, but the girl who handles it shows no fear as she deftly but carefully presses it into molds which separate it into the proper sizes for primers. She knows that in its present moist condition it cannot explode.

Extreme Precautions.

Or, perhaps, we may be watching one of the many loading machines. There is a certain suggestiveness in the way the machines are separated by part.i.tions. The man in charge takes a small carrier of powder from a case in the outside wall and shuts the door, then carefully empties it into the reservoir of his machine, and watches alertly while it packs the proper portions into the waiting sh.e.l.ls. He looks like a careful man, and needs to be. You do not stand too close.

The empty carrier then pa.s.ses through a little door at the side of the building, and drops into the yawning mouth of an automatic tube. In the twinkling of an eye it appears in front of the operator in one of the distributing stations, where it is refilled and returned to its proper loading machine, in order to keep the machine going at a perfectly uniform rate; while at the same time it allows but a minimum amount of powder to remain in the building at any moment. Each machine has but just sufficient powder in its hopper to run until a new supply can reach it. Greater precaution than this cannot be imagined, ill.u.s.trating as it does, that no effort has been spared to protect the lives of the operators.

How does an Artesian Well Keep Up Its Supply of Water?

Artesian wells are named after the French Province of Artais, where they appear to have been first used on an extensive scale.

[Ill.u.s.tration: ARTESIAN WELL (_D_) IN THE LONDON BASIN]

They are perpendicular borings into the ground through which water rises to the surface of the soil, producing a constant flow or stream. As a location is chosen where the source of supply is higher than the mouth of the boring, the water rises to the opening at the top. They are generally sunk in valley plains and districts where the formation of the ground is such that that below the surface is bent into basin-shaped curves. The rain falling on the outcrops of these saturates the whole porous bed, so that when the bore reaches it the water by hydraulic pressure rushes up towards the level of the highest portion of the strata.

The supply is sometimes so abundant as to be used extensively as a moving power, and in arid regions for fertilizing the ground, to which purpose artesian springs have been applied from a very remote period.

Thus many artesian wells have been sunk in the Algerian Sahara which have proved an immense boon to the district. The same has been done in the arid region of the United States. The water of most of these is potable, but a few are a little saline, though not to such an extent as to influence vegetation.

The hollows in which London and Paris lie are both perforated in many places by borings of this nature. At London they were first sunk only to the sand, but more recently into the chalk. One of the most celebrated artesian wells is that of Grenelle near Paris, 1,798 feet deep, completed in 1841, after eight years' work. One at Rochefort, France, is 2,765 feet deep; at Columbus, Ohio, 2,775; at Pesth, Hungary, 3,182, and at St. Louis, Mo., 3,843-1/2. Artesian borings have been made in West Queensland 4,000 feet deep. At Schladebach, in Prussia, there is one nearly a mile deep.

As the temperature of water from great depths is invariably higher than that at the surface, artesian wells have been made to supply warm water for heating manufactories, greenhouses, hospitals, fishponds, etc. The petroleum wells of America are of the same technical description. These wells are now made with larger diameters than formerly, and altogether their construction has been rendered much more easy in modern times.

Boring in the earth or rock for mining, geologic or engineering purposes is effected by means of augers, drills or jumpers, sometimes wrought by hand, but now usually by machinery, driven by steam or frequently by compressed air.

In ordinary mining practice a bore-hole is usually commenced by digging a small pit about six feet deep, over which is set up a shear-legs with pulley, etc. The boring rods are from ten to twenty feet in length, capable of being jointed together by box and screw, and having a chisel inserted at the lower end. A lever is employed to raise the bore-rods, to which a slight twisting motion is given at each stroke, when the rock at the bottom of the hole is broken by the repeated percussion of the cutting tool. Various methods are employed to clear out the triturated rock.

The work is much quickened by the subst.i.tution of steam power, water power, or even horse power for manual labor. Of the many forms of boring machines now in use may be mentioned the diamond boring machine, invented by Leschot, a Swiss engineer. In this the cutting tool is of a tubular form, and receives a uniform rotatory motion, the result being the production of a cylindrical core from the rock of the same size as the bore or caliber of the tube. The boring bit is a steel thimble about four inches in length, having two rows of Brazilian black diamonds firmly embedded therein, the edges projecting slightly. The diamond teeth are the only parts which come in contact with the rock, and their hardness is such that an enormous length can be bored with but little appreciable wear.

Where do Dates Come From?

Besides the dried dates which we are accustomed to seeing in this country, they are used extensively by the natives of Northern Africa and of some countries of Asia.

It consists of an external pericarp, separable into three portions, and covering a seed which is hard and h.o.r.n.y in consequence of the nature of the alb.u.men in which the embryo plant is buried.

Next to the cocoanut tree, the date is unquestionably the most interesting and useful of the palm tribe. Its stem shoots up to the height of fifty or sixty feet without branch or division, and of nearly the same thickness throughout its length. From the summit it throws out a magnificent crown of large feather-shaped leaves and a number of spadices, each of which in the female plant bears a bunch of from 180 to 200 dates, each bunch weighing from twenty to twenty-five pounds.