The side tubes are each provided with removable caps at the forward ends. These being removed, the plug at J and the two breech mechanisms being opened, the three tubes are clear for inspection and cleaning if found necessary.

The two breech mechanisms are of the slotted-screw type, the main provided with a gas check, that for the side or powder charge with hammer, mainspring, extractor, etc. Closing the block cocks the hammer, and a simple safety device is so arranged that it is impossible to fire until the block is completely locked.

The gun shown in the photographs is on a center-pivot carriage, but it is as readily mounted on a field or siege carriage for easy transportation, or on any other type of carriage, as it is entirely independent, the same as ordinary guns are.

On the mount shown the elevating and training gears are so arranged that the training shaft passes through the hollow elevating shaft, the two hand-wheels thus being on the same center, one just above the other. The shoulder piece attached to the left bracket of the carriage has a bearing for the shafts. The hand-wheels are thus brought so conveniently together that they may be worked by the left hand, while the right is free to hold and pull the lock lanyard.

The mount has otherwise no special features except the sight. This is so arranged that the directive element is entirely separated from that for elevation. A long bar, having a fixed front and a short vertically slotted rear sight-piece, is supported parallel to the axis of the gun, on one end by a rod to the trunnion bed of the carriage, the other at the shoulder-piece on a short slide adjustable at right angles, to provide correction for windage. These sight-pieces are fixed horizontally, so that the eye has the object constantly in view. The proper elevation is indicated by a range-bar, the lower end of which is attached to and recoils with the gun, the upper part sliding through a guide pivoted by the side of the rear sight to the shoulder-piece. This bar therefore moves vertically with the gun as it is elevated or depressed, the exact elevation being at once indicated by graduations on the bar reading against the top of its guide.

The whole sight thus becomes automatic, that is, no setting is required, the elevation or any alteration being coincidently shown by the range-bar, the direction of target being constantly

The side tubes are each provided with removable caps at the forward ends. These being removed, the plug at J and the two breech mechanisms being opened, the three tubes are clear for inspection and cleaning if found necessary.

The two breech mechanisms are of the slotted-screw type, the main provided with a gas check, that for the side or powder charge with hammer, mainspring, extractor, etc. Closing the block cocks the hammer, and a simple safety device is so arranged that it is impossible to fire until the block is completely locked.

The gun shown in the photographs is on a center-pivot carriage, but it is as readily mounted on a field or siege carriage for easy transportation, or on any other type of carriage, as it is entirely independent, the same as ordinary guns are.

On the mount shown the elevating and training gears are so arranged that the training shaft passes through the hollow elevating shaft, the two hand-wheels thus being on the same center, one just above the other. The shoulder piece attached to the left bracket of the carriage has a bearing for the shafts. The hand-wheels are thus brought so conveniently together that they may be worked by the left hand, while the right is free to hold and pull the lock lanyard.

The mount has otherwise no special features except the sight. This is so arranged that the directive element is entirely separated from that for elevation. A long bar, having a fixed front and a short vertically slotted rear sight-piece, is supported parallel to the axis of the gun, on one end by a rod to the trunnion bed of the carriage, the other at the shoulder-piece on a short slide adjustable at right angles, to provide correction for windage. These sight-pieces are fixed horizontally, so that the eye has the object constantly in view. The proper elevation is indicated by a range-bar, the lower end of which is attached to and recoils. with the gun, the upper part sliding through a guide pivoted by the side of the rear sight to the shoulder-piece. This bar therefore moves vertically with the gun as it is elevated or depressed, the exact elevation being at once indicated by graduations on the bar reading against the top of its guide.

The whole sight thus becomes automatic, that is, no setting is required, the elevation or any alteration being coincidently shown by the range-bar, the direction of target being constantly

The standard weight of projectile finally adopted for this caliber is 32 pounds. The powder chamber is reamed for 3-pdr. rapid-fire cartridge cases, in which 14 oz. smokeless powder, as manufactured by Dupont for the 3.20 Army field gun, is burned. Other powders may be used, however.

The body of the projectile (A, Plate 8) is of solid drawn brass, 4 inches outside diameter, No. 14 gauge, 26 inches long. The cylinder is threaded at each end on the inside for inch. A brass cap B having an internal thread is screwed in the front end to a shoulder. At the center of this cap is a thin brass tube C, 1 inches diameter, 7 inches long, projecting into the body of the projectile to receive the charge of dry gun-cotton. The inside of the front end of this small tube is threaded to receive a small cap-piece D containing the primer of 30 grains of fulminate. The head E of brass, constituting the body and containing the details of the safety fuze, is screwed into the cap. The body of the projectile is entirely filled with the explosive. The base F is an aluminum casting screwed into the rear of the tube. A tail-rod G of 3-inch steel tubing is rigidly secured to the base and projects 18 inches to the rear, where a vane-piece H, of cast aluminum, is secured. This vane-piece has eight spiral vanes at a pitch angle of one turn in 84 inches.

The weight of charge is 13 pounds, and may be of any explosive now known. Explosive gelatine containing 92 per cent. nitroglycerine has been repeatedly and successfully fired. There seems to be an almost utter absence of shock on the projectile, the force being applied more in the nature of a vigorous push rather than a blow.

The heat developed is not sufficient to be taken into consideration. After rapidly repeating shots, an ordinary tallow candle, slipped into a thin brass cup fixed in front of the gas-check in the main bore, shows no sign of melting. In fact, the bare hand can hardly note the increase of temperature on the inside of the bore immediately after firing.

The gun is remarkably uniform in action, and can be depended upon to group the projectiles within an exceedingly small space. The report of discharge is peculiar-not sharp, but rather muffled, and is actually so slight that a shot-gun can be heard much farther. There is absolutely an entire absence of smoke or vapor of any kind. There is no flame whatever in sight, and at night