Part 53 (1/2)

[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; s.h.i.+pping 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 battles.h.i.+p 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.)