[Ill.u.s.tration: GEAR WHEEL AND DRUM FOR COAL HOISTING PLANE

Diameter of wheel, 20 feet 9-1/2 inches; face, 43-1/2 inches; diameter of hub, 26 inches; number of teeth, 128; pitch, 6-1/8 inches; pitch diameter, 249.554 inches; shipping weight, 108,873 pounds.

_Courtesy of the Bethlehem Steel Co._]

[Ill.u.s.tration: SIX-INCH RIBBED CAVITY ARMOR-PIERCING Sh.e.l.l

Projectile was loaded with two pounds of black charcoal powder and fused with magazine fuse. Fired at six-inch Krupp hard-faced armor plate.

Sh.e.l.l burst about eight feet to rear of plate after penetrating the same. Weight of largest fragment recovered 10-1/4 pounds. Average weight of fragments, 2-5/16 ounces. Total number of pieces recovered, 650.

_Courtesy of the Bethlehem Steel Co._]

AMMUNITION. (See page 402.)

Made-up ammunition, with bra.s.s cartridge cases, and cast-iron and forged steel sh.e.l.ls and armor-piercing projectiles. The rounds shown are as follows: Rounds with forged steel sh.e.l.l for one-pounder gun, for three-pounder gun and for six-pounder gun respectively; round with cast-iron sh.e.l.l for three-inch field gun; round with capped armor-piercing sh.e.l.l for three-inch fifty-caliber rapid-fire gun; round with forged steel sh.e.l.l for four-inch forty caliber rapid-fire gun; round with capped armor-piercing projectiles for the four-inch and twelve-centimeter fifty-caliber rapid-fire guns respectively, and round with forged sh.e.l.l for six-inch gun.

TWO-HANDED ELEVATING GEAR. (See page 402.)

Method of obtaining a variable movement of a miniature target, corresponding to rolls of a vessel of from 1 to 10 degrees. A series of 25,000 shots were fired thus, by eight gun pointers, at targets corresponding to the size of a battleship as seen at ranges of 1,500, 3,000, 6,000 and 9,000 yards. Using a sub-caliber rifle rigidly attached to the muzzle of the gun and fired electrically by the firing gear of the big gun. The record shows that under circ.u.mstances of average difficulty at sea (say 5 degrees roll and range of 3,500 yards), the gain in accuracy (increase in hits with a given expenditure of ammunition) is about 25 per cent, and the gain in speed of hitting (number of hits in a given time) is 50 per cent, with the two-hand gear as compared with the usual one-hand gear.

RANGE FINDER AND PREDICTOR; HOME AND DISTANT STATION INSTRUMENTS. (See page 403.)

Continuous readings, by means of automatic indicators, of either the actual or the predicted ranges and azimuths of moving target at every instant and for any distance from 1,000 to 15,000 yards and through an azimuth of 160 degrees, are clearly presented at all times. The ranges are read in scales of 10-yard steps, and the azimuths for each .01 degree are traversed. The corrected ranges for the various guns served by the instruments, either actual or automatically predicted for any interval of time, are constantly communicated to the various guns whose fire is being directed by the observation instrument.

ARMOR-PIERCING PROJECTILES, CAPPED AND UNCAPPED. (See page 403.)

The projectiles shown are a three-inch capped, a four-inch capped, a five-inch and a six-inch uncapped, eight-inch uncapped and capped, ten-inch uncapped and capped and twelve-inch capped.

RANGE FINDER WITH CHART ATTACHMENT. (See page 404.)

The chart is drawn on the lower and ground side of a ground gla.s.s plate.

A pencil point is secured to moving cross-head and marks position of target on ground gla.s.s, tracing movement of same thereon. The pillar mounting allows of ready removal of chart attachment when it is not desired to use the same.

EIGHTEEN-INCH, THIRTY-CALIBER TORPEDO GUN. (See page 404.)

Weight, 134,000 pounds. Length of gun, 528 inches. Weight of projectile, 2,000 pounds. Travel of projectile in bore, 432.4 inches (24.02 calibers). Weight of charge, 310 pounds of smokeless powder. Muzzle velocity, 2,000-foot seconds. Muzzle energy, 55,500-foot tons. Greatest diameter of gun, 45 inches. Its breech mechanism was opened and closed by one man in nine seconds. It was also opened without great effort by a boy twelve years of age.

FIRING GEAR FOR GUNS. (See page 405.)

External firing gear for guns using loose ammunition. The primer is inserted in the firing gear when the breech mechanism is open, but is held at an angle to the lighting vent until the final locking motion of the breech block, making it impossible to light the gun's charge before the breech mechanism is safely closed, even if the primer should be prematurely exploded. The primer case is automatically ejected by the opening of the breech mechanism.

FUSES. (See page 405.)

The fuses shown from left to right are: minor caliber percussion fuse, minor caliber magazine percussion fuse, major caliber percussion fuse, major caliber magazine percussion fuse, triple, double and single train time fuses. The time fuses all contain a percussion element to insure their exploding on impact if not previously exploded. No special tool is required for setting these fuses. They are made up to 27 seconds burning time for guns of 2,600-foot seconds muzzle velocity, and up to 36 seconds for mortars and guns of 1400-foot seconds muzzle velocity.

What is a Deep-Sea Diver's Dress Like?

There are now two general types of deep-sea diving equipment: an India rubber dress, covering the entire body, except the head, which is covered by a helmet, and another apparatus which is constructed entirely of metal.

The India rubber dress has a neck-piece or breast-plate, fitted with a segmental screw bayonet joint, to which the head-piece or helmet, the neck of which has a corresponding screw, can be attached or removed. The helmet has usually three eye-holes, covered with strong gla.s.s, and protected by guards. Air is supplied by means of a flexible tube which enters the helmet and communicates with an air pump above. To allow of the escape of the used air there is sometimes another flexible tube, which is led from the back part of the helmet to the surface of the water. But in the more improved forms of the dress, the breathed air escapes by a valve so constructed as to prevent water from getting in, though it lets the air out. Leaden weights are attached to the diver, and his shoes are weighted, that he may be able to descend a ladder, walk about below, etc.

[Ill.u.s.tration: DIVING-DRESS AND DIVING-HELMET, BY SIEBE, GORMAN & CO.

A. Pipe by which air is supplied.

B. Valve by which it escapes.]

Communication can be carried on with those above by means of a cord running between the diver and the attendants; or he may converse with them through a speaking tube or a telephonic apparatus. One form of diving-dress makes the diver independent of any connection with persons above the water. It is elastic and hermetically closed. A reservoir containing highly compressed air is fixed on the diver's back, which supplies him with air by a self-regulating apparatus at a pressure corresponding to his depth. When he wishes to ascend he simply inflates his dress from the reservoir.

Another form, known as the Fleuss dress, makes the diver also independent of exterior aid. The helmet contains a supply of compressed oxygen, and the exhaled breath is pa.s.sed through a filter in the breast-piece which deprives it of its carbonic acid, while the nitrogen goes back into the helmet to be mixed with the oxygen, the supply of which is under the diver's own control, and to be successively breathed.

A diver has remained an hour and a half under thirty-five feet of water in this suit.

A considerable enlargement of the field of deep-sea diving is the result of the invention recently of a form of diving apparatus which is unaffected by the limitations. .h.i.therto imposed on work of this kind. A possible depth of 204 feet is recognized by the British Admiralty regulations under the conditions that obtain with the common form of diving suit. Yet this depth has probably never been reached. One hundred feet is the rare descent of the average diver and 150 feet his maximum.

With the new apparatus a submergence of 212 feet has been obtained, and this might have been indefinitely extended had there been a greater depth of water at the place where the experiment took place--Long Island Sound during the latter part of 1914.

The new diving apparatus is constructed entirely of metal, is rigid and is made of such materials that it is strong enough to resist the great pressures found in the depths to which it can penetrate. The material used is an alloy of aluminum, and the diving case weighs complete about 500 pounds. When in the air, the man inclosed in it is incapable of imparting movement to it, but in the water, which counterbalances the dead weight of the apparatus, he can easily move the articulated sections as well as give himself motion through the water. The articulated portion consists of about fifty turning joints, fitted with leather packing, which swells and has an increased effectiveness under increased water pressure. To prevent the pressure-force of the deep sea from jamming the joints, roller bearings are so arranged about them that freedom of action is constantly maintained.

The diving case is not absolutely water-tight, nor is it desired that it should be so, as the slight leakage acts as a lubricant to the joints, and aids in their movements. The danger arising from the intake of water thus into the diving case is averted by the action of an ingenious pump appliance, which serves two purposes: that of pumping the water out and pumping the air in. The diver in this invention carries his pump with him and has air supplied to him at atmospheric pressure.

At the back of the diving case is a recess and in it is installed a compact but powerful pump, which sucks from the feet of the suit all leakage and forces it at once outward. This pump is worked by compressed air, and the air, after performing its mechanical part of driving the pump, is exhausted into the suit for the diver to breathe and then pa.s.ses to the surface through the free s.p.a.ce in an armored rubber tube, within which are led down to the diver the compressed air pipe for driving the pump, and the electrical connections for telephone and lamp.

Thus the diving case receives a thorough ventilation, and it has been found that should the pump fail to work for a number of minutes there would still be enough air remaining in the diving case and the tube s.p.a.ce to supply the diver's needs for at least the length of time he is being hauled to the surface.

During the experiment in Long Island Sound the pump was stopped for ten minutes, while the diver was at a depth of 100 feet. He suffered no inconvenience, and when the compressor again was started he was lowered to a depth of 212 feet. If such a condition as failure of the pump to work for ten minutes had arisen during a descent in the old elastic diving dress the result must necessarily have been fatal. Nor is a delay necessary in hoisting the diver clad in the new diving apparatus to the surface. According to the British Admiralty regulations, should a diver go down to a depth of 204 feet, the time of his ascent must be not less than one hour and a half. In the Long Island Sound experiments the diver was hoisted to the surface in eighty-seven seconds. He was totally unaffected by the abrupt change in pressure, although the deepest he had ever been was ninety feet, and on that occasion he had suffered from bleeding at the nose and ears.

Why do We Smile when We are Pleased?

We smile to express our pleasure. When you meet a friend on the street you smile as you greet him. This is an indication of your pleasure at seeing him. This is often caused by an unconscious nervous action produced by the impression the occurrence creates on the brain. You do not have to think about smiling, but the muscles of your face contract and give you that pleased look without any effort on your part.

Why do Some of Us have Freckles?

Some people have freckles, when others do not, because all skins are not alike, just the same as eyes are not all of one color. People with certain kinds of skin freckle more quickly when the skin is exposed to the sun. The action of the sun on their skin causes small parts of the second layer of skin to give out a yellow or yellowish brown substance.

Freckles are most common in persons of fair complexion and hair. In some cases freckles are permanent, but in most cases they disappear with the coming of cold weather.