Inventions of the Great War

by A. Russell Bond

Search-light Shell and
one of its Candles

GUNS THAT PLAY HIDE-AND-SEEK

A very ingenious invention is the disappearing-mount which is used on our coast fortifications. By means of this a gun is hidden beyond its breastworks so that it is absolutely invisible to the enemy. In this sheltered position it is loaded and aimed. It is not necessary to sight the gun on the target as you would sight a rifle. The aiming is done mathematically. Off at some convenient observation post, an observer gets the range of the target and telephones this range to the plotting-room, where a rapid calculation is made as to how much the gun should be elevated and swung to the right or the left. This calculation is then sent on to the gunners, who adjust the gun accordingly. When all is ready, the gun is raised by hydraulic pressure, and just as it rises above the parapet it is automatically fired. The recoil throws the gun back to its crouching position behind the breastworks. All that the enemy sees, if anything, is the flash of the discharge.

Now that airplanes have been invented, the disappearing-mount has lost much of its usefulness. Big guns have to be hidden from above. They are usually located behind a hill, five or six miles back of the trenches, where the enemy cannot see them from the ground, and they are carefully hidden under trees or a canopy of foliage or are disguised with paint.

The huge guns recently built to defend our coasts are intended to fire a shell that will pierce the heavy armor of a modern dreadnought. The shell is arranged to explode after it has penetrated the armor, and the penetrating-power is a very important matter. About thirty years ago the British built three battle-ships, each fitted with two guns of 16¼-inch caliber and 30-caliber length. In order to test the penetrating-power of this gun a target was built, consisting first of twenty inches of steel armor and eight inches of wrought-iron; this was backed by twenty feet of oak, five feet of granite, eleven feet of concrete, and six feet of brick. When the shell struck this target it passed through the steel, the iron, the oak, the granite, and the concrete, and did not stop until it had penetrated three feet of the brick. We have not subjected our 16-inch gun to such a test, but we know that it would go through two such targets and still have plenty of energy left. Incidentally, it costs us $1,680 each time the big gun is fired.

THE FAMOUS FORTY-TWO-CENTIMETER GUN

One of the early surprises of the war was the huge gun used by the Germans to destroy the powerful Belgian forts. Properly speaking, this was not a gun, but a howitzer; and right here we must learn the difference between mortars, howitzers, and guns. What we usually mean by "gun" is a piece of long caliber which is designed to hurl its shell with a flat trajectory. But long ago it was found advantageous to throw a projectile not at but upon a fortification, and for this purpose short pieces of large bore were built. These would fire at a high angle, so that the projectile would fall almost vertically on the target.

As we have said, the bore of a gun is rifled; that is, it is provided with spiral grooves that will set the shell spinning, so as to keep its nose pointing in the direction of its flight. Mortars, on the other hand, were originally intended for short-range firing, and their bore was not rifled. In recent years, however, mortars have been made longer and with rifled bores, so as to increase their range, and such long mortars are called "howitzers." The German 42-centimeter howitzer fired a shell that was 2,108 pounds in weight and was about 1½ yards long. The diameter of the shell was 42 centimeters, which is about 16½ inches. It carried an enormous amount of high explosive, which was designed to go off after the shell had penetrated its target. The marvel of this howitzer was not that it could fire so big a shell but that so large a piece of artillery could be transported over the highroads and be set for use in battle. But although the 42-centimeter gun was widely advertised, the real work of smashing the Belgian forts was done by the Austrian "Skoda" howitzers, which fired a shell of 30.5-centimeter (12-inch) caliber, and not by the 42-centimeter gun. The Skoda howitzer could be taken apart and transported by three motor-cars of 100 horse-power each. The cars traveled at a rate of about twelve miles per hour. It is claimed the gun could be put together in twenty-four minutes, and would fire at the rate of one shot per minute.

FIELD-GUNS

So far, we have talked only of the big guns, but in a modern battle the field-gun plays a very important part. This fires a shell that weighs between fourteen and eighteen pounds and is about three inches in diameter. The shell and the powder that fires it are contained in a cartridge that is just like the cartridge of a shoulder rifle. These field-pieces are built to be fired rapidly. The French 75-millimeter gun, which is considered one of the best, will fire at the rate of twenty shots per minute, and its effective range is considerably over three miles. The French supplied us with all 75-millimeter guns we needed in the war, while we concentrated our efforts on the manufacture of ammunition.