be in battery, it must be brought across the platform, or made to point to the rear, to give room for working the lever.

The operation is only applicable to garrison carriages.

Dismounting a gun.

PREPARE TO DISMOUNT THE GUN. BEAR DOWN. FIX THE COLLARS. EASE OFF. PLACE THE FRONT BOXES. BEAR DOWN. RUN THE CARRIAGE BACK. HALT. PLACE THE REAR BOXES. EASE OFF. (LIFT. LOWER. BEAR DOWN. EASE OFF, to be given alternately, and the boxes or blocks to be removed, or put under the gun, so as to diminish the height from two to four inches at a time.)

Mounting the gun.

The operations are exactly the converse of the foregoing.

TO MOUNT, AND DISMOUNT MORTARS ON, AND FROM THEIR BEDS. Part 3.-Art. 25.

4 handspikes. 2 drag-ropes. 1 wrench. 1 hammer.

8 men.

4 men.

The mortar is supposed to be lying vent upwards, breech towards the bed, the breast of which is towards the mortar. Capsquares removed.

Mounting.

RAISE THE MORTAR ON ITS MUZZLE.

HEAVE, AND HAUL.

RUN THE BED UP. SHIFT THE DRAG-ROPES. HEAVE, AND HAUL. BRING THE MORTAR VERTICAL. HEAVE, AND HAUL.

Dismounting.

BRING THE MORTAR VERTICAL. HEAVE, AND HAUL. HALT. TAKE OFF CAPSQUARES. FIX THE DRAG-ROPES.

HAUL.

TO MOUNT, AND DISMOUNT HOWITZERS.

Part 3.-Art. 28.

HEAVE, AND

10-inch howitzer, 1 non-commissioned officer, and 18 men. 8-inch howitzer, 1 non-commissioned officer, and 12 men.

One lever. Four or six handspikes. Two fulcrums. Two pairs of drag-ropes, or one pair and a parbuckling rope. Two or three pieces of skidding. One hammer.

TO RAISE A 10-INCH HOWITZER ON ITS MUZZLE, WITH

DRAG-ROPES.

The howitzer is supposed to be lying on the ground, vent upwards.

PREPARE TO RAISE THE BREECH. BEAR DOWN. HOOK DRAG-ROPES ΤΟ CASCABLE. PREPARE TO HOWITZER ON ITS MUZZLE. HEAVE, AND HAUL.

EASE OFF.

RAISE THE

TO MOUNT A 10-INCH HOWITZER ON A GARRISON CARRIAGE.

The howitzer is supposed to be standing on its muzzle. RUN THE CARRIAGE FORWARD. SCOTCH THE TRUCKS. PREPARE TO RAISE THE TRAIL. LIFT. HALT. PUSH THE HOWITZER FIX THE DRAG-ROPES. HEAVE, AND HAUL.

ON THE CARRIAGE.

TO DISMOUNT A 10-INCH HOWITZER FROM A GARRISON CARRIAGE.

SCOTCH THE TRUCKS. PREPARE TO RAISE THE CARRIAGE. HEAVE (OR LIFT). HOOK DRAG-ROPES ON CASCABLE. HAUL OUT THE HOWITZER (OR RAISE HOWITZER ON MUZZLE). RUN THE CARRIAGE BACK. PREPARE TO LOWER THE HOWITZER. PUSH THE HOWITZER OVER.

TO MOUNT AN 8-INCH HOWITZER ON A TRAVELLING CARRIAGE.

The howitzer resting on its muzzle, and carriage run up, capsquares removed.

PREPARE ΤΟ UNLIMBER. UNLIMBER. LIFT THE TRAIL.* HALT. PUSH HOWITZER ON CARRIAGE. PUT ON CAPSQUARES. TAKE A PURCHASE UNDER MUZZLE. LIMBER UP.

TO MOUNT AN 8-INCH HOWITZER ON A GARRISON CARRIAGE, Is performed precisely the same as the 10-inch howitzer.

TO DISMOUNT AN 8-INCH HOWITZER FROM A TRAVELLING CARRIAGE.

* Vide preceding. When the trail is nearly vertical,

PLACE HANDSPIKES FOR MUZZLE. UNKEY CAPSQUARES. HOOK DRAG-ROPES. HAUL HOWITZER OUT OF CARRIAGE. LOWER THE TRAIL (OR LIMBER UP). RUN CARRIAGE BACK. HOWITZER (OR PUSH THE HOWITZER OVER).

LOWER THE

To dismount an 8-inch howitzer from a garrison carriage, is performed as detailed for the 10-inch howitzer.

2, 4, 6, or 8 handspikes, 1 hammer, 2 double lashings. For the 68-pounder carronade, which is mounted by parbuckling, 2 skids, about 8 or 9 feet long, or 4 pieces, each about 24 feet long, 2 parbuckles.

TO MOUNT A 68-PR. CARRONADE BY PARBUCKLING.

1st. In the common way, with skids.

PLACE SKIDS, AND PARBUCKLES. PINCH THE CARRONADE FORWARD. HEAVE. HALT. PUT IN THE BOLT.

2nd. Over the trail of the carriage.

RAISE THE CARRONADE. RUN THE CARRIAGE BACK. FIX PARBUCKLES. HEAVE, AND HAUL. PLACE HANDSPIKES. HEAVE AND HAUL. CAST OFF PARBUCKLES. SLEW THE CARRONADE.

PINCH THE CARRONADE FORWARD.

A 68-POUNDER MAY BE DISMOUNTED by the converse of either of the foregoing modes; or it may be dismounted by throwing it off the carriage to the ground.

TO MOUNT A 24-PR. CARRONADE.

PREPARE TO MOUNT THE CARRONADE.

LIFT. LIFT. LIFT. HALT. CAST OFF LASHING ROPES, AND HANDSPIKE. PUT IN

CARRONADE BOLT.

TO DISMOUNT A 24-PR. CARRONADE.

The elevating screw, and carronade bolt are removed, and the lashing, and handspikes arranged as before.

HEAVE, (OR LIFT. .) HEAVE, (OR LIFT.) HEAVE, (OR LIFT.) The carronade may also be dismounted by throwing it off the carriage.

TO MOUNT A 12-PR. CARRONADE.

Performed in the same manner as the 24-pounder carronade.

188

PART VIII.

GUNNERY.

By the Parabolic Theory, the greatest range is when the angle of elevation is 45°, or half a right angle; and the ranges are equal at angles, equally above and below 45°. In projectiles, moving with velocities not exceeding 300 or 400 feet per second of time, the Parabolic Theory will resolve cases tolerably near the truth; but in cases of great projectile velocities, that theory is quite inadequate, without the aid of data, drawn from good experiments; for so great is the effect of the resistance of the air to projectiles of considerable velocity, that some of those, which in the air range only two or three miles, would, in vacuo, range between twenty and thirty miles. The effects of this resistance are also various, according to the velocity, the diameter, and the weight of the shot.

By experiments it will be found that the greatest range (instead of being constantly that at an elevation of 45°, as in the Parabolic theory), will be at all intermediate degrees between 45° and 30° (with ordinary charges about 42°), being more or less, both according to the velocity and the weight of the projectile; the smaller velocities and larger shells ranging farthest when projected almost at an elevation of 45°; while the greatest velocities, especially with the smaller shells, range farthest with an elevation of about 30°. However, as sufficient experiments have not yet been made to establish true rules for practical gunnery, independent of the Parabolic theory, we must at present content ourselves with the data of some one certain experimental range, and time of flight at a given angle of elevation, and then, by help of these and the Parabolic theory, we can determine the like circumstances for other elevations that are not greatly different from the former, assisted by the following rules:

PRACTICAL RULES IN GUNNERY.

1.-To find the velocity of any shot, or shell.

It has been found by experiments, that with shot of mean windage, and powder of mean strength, a charge of one-third of the weight of the ball gives an initial velocity of about 1600 feet per second therefore, to find the velocity given by any other charge, divide three times the weight of the charge by the weight of the ball, and multiply the square root of the quotient by 1600,

the product will be the velocity in feet, or the space the shot passes over in the first second.*

2. The first graze, with given elevation, and charge, being known, to determine the charge for any other first graze, and elevation.

Multiply the known charge and elevation into the proposed first graze, also the proposed elevation into the known first graze, and divide the first product by the last, for the charge required in

ounces.

3. Given the range for one charge, to find the range for another charge, or the charge for another range.

The ranges have the same proportion as the charges; that is, as one range is to its charge, so is any other range to its charge, the elevation of the piece being the same in both cases.

From experiments on the velocities of shot, the following results have been obtained :

1. The time of a ball's flight is nearly as the range, the gun and elevation being the same.

2. The velocities decrease as the distances increase (arising from the resistance of the air, which opposes the progress of the shot,) in a proportion somewhat higher than the squares of the velocities throughout, and subject only to a small variation.

3. Very little advantage is gained, in point of range, by increasing the charge more than is necessary to attain the object, the velocities given by large charges being very soon reduced to those by moderate charges; those, for instance, given by half the shot's weight are reduced to an equality with those by one-third, after passing through a space of only 200 feet. (Vide 8.)

4. Very little benefit is derived from increasing the length of guns, the velocity given by long guns of 22 calibres being reduced to an equality with that of short guns of 15 calibres with similar charges, after passing through the following spaces-viz. :

* By the last ballistic experiment, conducted in May, 1837, it was found that, with a heavy 6-pounder gun, a charge of 14lb. gave a velocity of 1740 feet, and a charge of 21b. a velocity of 1892 feet per second. The shot employed were of a high guage, windage only '078 inch, and the powder was of the strongest quality; the weight of the pendulum fired into was 58 cwt. 3 qrs. 16 lb. A light 6-pounder, two feet shorter than the heavy 6-pounder, with similar charges, gave velocities of about 190 feet less.