Observers at favorable stations on the Potomac River cut in the splashes with theodolites. Their observations are plotted on a plotting board on which are permanently marked the observing stations. The exact position of each splash is thus located and the mean range and dispersion both of test and station projectiles obtained.

During firing the projectiles must not strip their bands, break up or flight erratically.

Projectiles are fragmented in an explosion chamber by exploding electrically a service charge of explosive in the shell cavity. The resulting fragments must be satisfactory in number, size and shape, in order that the maximum damage may be done when bursting on board an enemy vessel.

Common projectiles are tested by ranging and fragmenting a specified number of projectiles per contract, as described for armor-piercing projectiles. Plate test is against special treatment steel plate of a thickness and at a velocity laid down in the specifications for the contract. Projectiles are recovered from the sand butt behind the plate by a bucket crane.

High capacity and flat-nose projectiles and shrapnel are fragmented and ranged, as laid down in the specifications. Shrapnel is also tested in accordance with specifications similar to those of the army.

Target projectiles are ranged, three per lot, at service velocity. Proof of Fuses and Tracers.-Detonating fuses of various types are tested in accordance with the instructions of the Bureau of Ordnance. All detonating fuses in shell filled with high explosive are fired in a covered butt to prevent the spread of frag

ments.

All major, medium and minor caliber tracer and ignition fuses have samples from each lot submitted for test.

The proof consists of several tests which ensure their safety and satisfactory functioning in service. These tests consist of: 1. Drop test.

2. Fragmentation test.

3. Flight test.

4. Plate tests.

5. Tracer test.

The drop test consists of dropping a blind loaded projectile, in which the fuse has been inserted, a distance of 30 feet or more. The fuse must not arm or the tracer, if fitted, ignite.

The fragmentation test is made by causing a fuse to act in a service projectile filled with service explosive.

For the flight test, a projectile loaded with black powder, with the fuse inserted, is fired down the range. The fuse must not act prematurely or in flight.

For plate test, several projectiles, loaded and fused as for service, are fired through plates three-sixteenths of an inch, or above, at service velocity, or below, as specified. The fuses must function satisfactorily in all cases.

For tracer test of fuses so fitted, three are fired in service projectiles at night, down the range. Two out of three must function satisfactorily so as to be followed by the eye for 12 seconds. Two or more timekeepers are used and the gun is served as rapidly as possible.

Time fuses are tested in shrapnel to determine time of functioning and variation from the mean time of burst. They are also given percussion tests at plank, canister test at o seconds setting and graze test on a pile of sand. In all cases they must function satisfactorily.

Special fuses are given special proofs, as laid down in the specifications under which they were manufactured.

Proof of Armor.-Armor is proved by determining its ability to withstand the attack of an enemy's projectiles at battle ranges, and the test simulates actual conditions as far as possible. A sample plate from each lot is selected by the inspector at the works of the manufacturer, who chooses the plate expected to give the poorest ballistic results. The sample plate is shipped by rail to the proving ground. Class "A" (face-hardened) plates are set by a large locomotive crane against heavy oak timber structures in front of sand butts. The plate is backed or unbacked in accordance with specifications and is secured to simulate service conditions.

The test is carried out in a similar manner to an armor-piercing shell test. The gun is usually of approximately the same caliber as the thickness of the plate. Velocity and pasteboard screens are used. The projectiles are those known to be of uniform quality. Tubes and plates are placed in front of the plate to prevent the scattering of fragments.

Several rounds are fired. After each, the plate is inspected to be sure that it has defeated the projectile in every respect, as laid down by the specifications. Measurements are taken and recorded, as in the case of shell tests. After the completion of the test, or sometimes after each round, the plate is stencilled with the striking velocities and photographed. (See Fig. 5.)

Plates passing successful test become the government's propterty and are available for test of armor-piercing projectiles. Failed plates are the manufacturer's property and are returned at his expense.

Class "B" plates (special treatment steel, such as turret and conning-tower tops) and protective deck plates are set for test so that the projectile strikes at an angle equal to the anticipated angle of fall of an enemy's shell. As it is impractical to strike a plate in a horizontal position because of the ricochet of the projectile, the plate is set vertically and the projectile caught in a sand butt behind. The plate must not fracture under the impact.

Full reports are made to the bureau of the ballistic results. Proof of Explosives.-Explosives are tested by using samples of each lot to fragment service projectiles in an explosion chamber. Each sample must function in a satisfactory manner.

Proof of Cartridge Cases.-Cartridge cases are proved by firing sample cases three rounds each, thus ensuring satisfactory

functioning in service. The case must load and eject easily on each round and must be free of deformation, splits or other serious defects.

Proof of Primers.-Primers are proved in accordance with specifications laid down by the bureau. When possible they are tested during current work. Combination primers have several of the proof lot fired electrically and several by percussion. Primers must not misfire, split or rupture. Should they do so, the lot they represent is rejected, and the failed sample primers are returned to the manufacturer.

Proof of Bombs.--Bombs are tested in accordance with specifications, which, as in the case of other material, are to ensure their proper functioning in service. Service conditions are adhered to as closely as possible.

Special Work and Experimental Work.-A definite division between these two classes of work cannot be clearly made. However, such tests as are possible are carried out in connection with proof work. For example, data are collected relative to ranging, erosion, life of guns, new types of ordnance material and questions which have arisen in the fleet. Research and development work are done, using special types of apparatus designed to give accurate results. The proving ground is available for such tests as are desired by officers of the navy to determine definitely points in dispute or in development as to ordnance material or the effect of ordnance material on material under the cognizance of other bureaus. Such tests must receive the approval of the Bureau of Ordnance before being conducted.

Duty-Duty at the proving grounds is one of the most satisfactory shore details. The work is exacting, but is full of live interest and is in constant touch with modern developments in ordnance. Younger officers of the service considering their first shore details would do well to request this duty, either as a regular assignment or as a part of ordnance postgraduate instruction. Recommendations.-Once again it is urged that officers at sea or on combatant shore duty remember that the bureau and the proving grounds are anxious to obtain data relative to unsatisfactory functioning of ordnance material. The only way the officers supplying material can know whether it is good or bad in actual service, with the exception of their own experiences, is to receive detailed reports from the officers using the material.

[COPYRIGHTED]

U. S. NAVAL INSTITUTE, ANNAPOLIS, MD.

PUTTING 'EM ACROSS

By LIEUT. COMMANDER K. C. MCINTOSH, P. C., U. S. Navy

“Can you whack her up to fifteen?" asked Moorshead. A thin cough ran up the speaking tube. "I think so, sir, but I would prefer to have the engine-room hatches open at first."-Their Lawful Occasions, KIPLING.

Four months before she had been a filthy, black-iron pot, her decks scarred and rotting, her bilges crammed with a rusting jigsaw puzzle made up of parts of every machinery installation formerly on board. The jagged edges of her cylinders leered through the grime of the engine-room in a double row-a huge. abscessed lower jaw throbbing for lack of a dentist. The crippled furniture of the saloons sagged under the staring eyes of the bleared chromo panels in the bulkheads, the ripped cushions spewing dusty horsehair over the torn linoleum.

Now she was in trim gray with a pair of giddy, black destroyers romping along her side by way of camouflage. Her woodwork glistened with much varnish and her cushions smelled of new leather. Down below, the chief was saying hopefully that "she ought to mote-at any rate, she isn't hitting anywhere." Five hundred pink boys, whose overshirts still sat strangely upon unaccustomed shoulders, were watching the stream of khaki coming over the side and sternly resolving that in case they should be seasick, none of the doughboys must be allowed to suspect it. The doughboys were gratefully heaving their packs into the bunks assigned and with clattering mess-kits lining up at the after galley for a much desired supper.

Boatswain's mates began to roar in voices that had not yet acquired a salty raucousness, and flushed second lieutenants began herding the soldiers below and out of sight. The dock suddenly slid away, then the slow throb of the engines showed that the ship was moving. As the sun set, she dropped down the river. That night she was away, slipping out into the dark. Another transport was at work. The navy was putting across