Read Ebook: The hand-book of artillery by Roberts Joseph

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Ebook has 311 lines and 32828 words, and 7 pages

The pages refer to the sidenotes in the margin of the text.

Preface, 5 General Table of Contents, 7

Appendix--Rifle Cannon, 163 Index, 169

THE HAND-BOOK OF ARTILLERY.

ARTILLERY IN GENERAL.

Heavy fire-arms of every description.

Four, viz.: Guns, Howitzers, Columbiads, and Mortars.

According to their use as Sea-coast, Garrison, Siege, and Field Artillery.

All heavy artillery, such as that for sea-coast, siege, and garrison equipment, is made of iron; and that for field service, of bronze.

This metal, having greater tenacity and strength than iron, the pieces can be made lighter.

Iron is less expensive than bronze, and is more capable of sustaining long-continued firing with larger charges; such pieces are, therefore, better calculated for the constant heavy firing of sieges.

The difficulty of forming a perfect alloy, in consequence of the difference of fusibility of tin and copper.

This term is applied to one or more pieces, or to the place where they are served.

The tenacity and elasticity of the metals employed in their fabrication. Their thickness must be proportioned to the effect developed by the powder; and the length is determined by experiment, and should not exceed 24 calibres. The exterior surface of a cannon is composed of several surfaces, more or less inclined to the axis of the bore, the forms of which have been determined by experiment.

Because the elastic force of the inflamed gunpowder is there greatest, constantly diminishing in intensity as the space increases in which it acts.

The distance from the rear of the base-ring to the face of the piece.

From the rear of the cascable to the face.

It includes the part bored out, viz: the cylinder, the chamber , and the conical or spherical surface connecting them.

The diameter of the bore.

Divide the length of the cylinder, in inches, by the number of inches in the calibre.

Multiply the number of calibres by the calibre in inches.

Artificial marks on the piece for determining the line of fire.

Usually by means of the gunner's level, when the trunnions are perfectly horizontal.

It is a line drawn from the highest point of the base-ring to the highest point on the swell of the muzzle.

An imaginary line passing through the centre of the bore.

It is the angle which the natural line of sight makes with the axis of the piece.

It is the difference of the semi-diameter of the base-ring and the swell of the muzzle, or the muzzle-band. It is, therefore, the tangent of the natural angle of sight to a radius equal to the distance from the rear of the base-ring to the highest point of the swell of the muzzle, or the front of the muzzle-band, as the case may be, measured parallel to the axis.

The BASE OF THE BREECH is a frustum of a cone, or a spherical segment in rear of the breech.

The BASE-RING is a projecting band of metal adjoining the base of the breech, and connected with the body of the gun by a concave moulding.

The BREECH is the mass of solid metal behind the bottom of the bore, extending to the rear of the base-ring.

The REINFORCE BAND is at the junction of the first and second reinforces in the heavy howitzers and columbiads.

The CHASE is the conical part of the gun in front of the reinforce.

The NECK is the smallest part of the piece in front of the astragal or the chase ring.

The FACE of the piece is the terminating plane perpendicular to the axis of the bore.

The TRUNNIONS are cylinders, the axes of which are in a line perpendicular to the axis of the bore, and in the same plane with that axis.

The BORE of the piece includes all the part bored out, viz.: the cylinder, the chamber , and the conical or spherical surface connecting them.

The CHAMBER in howitzers, columbiads, and mortars, is the smallest part of the bore, and contains the charge of powder. In the howitzers and columbiads, the chamber is cylindrical; and is united with the large cylinder of the bore by a conical surface; the angles of intersection of this conical surface with the cylinders of the bore and chamber, are rounded by arcs of circles. In the 8-inch siege howitzer, the chamber is united with the cylinder of the bore by a Spherical surface, in order that the shell may when necessary, be inserted without a sabot.

The new columbiad is made without a chamber.

The BOTTOM OF THE BORE is a plane perpendicular to the axis, united with the sides by an arc of a circle the radius of which is one-fourth of the diameter of the bore at the bottom. In the columbiads, the heavy sea-coast mortars, stone mortar, and eprouvette, the bottom of the bore is hemispherical.

The MUZZLE, or mouth of the bore, is chamfered to a depth of 0.15 inch to 0.5 inch , in order to prevent abrasion, and to facilitate loading.

The TRUE WINDAGE is the difference between the true diameters of the bore and of the ball.

The aperture through which fire is communicated to the charge.

It should be as small as the use of the priming wire and tube will allow.

As the velocity of the gases arising from the combustion of the powder is extremely great, a large amount escapes through the vent, which contributes nothing to the velocity of the projectile. It therefore follows, that the effect produced by a given charge will diminish as the diameter of the vent increases. Besides, on account of the increase of power in the current that escapes from them, large vents are more rapidly injured than small ones.

The axis of the vent, is in a plane passing through the axis of the bore, perpendicular to the axis of the trunnions. In guns, and in howitzers having cylindrical chambers, the vent is placed at an angle of 80? with the axis of the bore, and it enters the bore at a distance from the bottom equal to one-fourth the diameter of the bore. As this inclination renders it easy to pull the friction tube out of the vent, that of the new 12-pdr. field gun, and the new columbiads has been placed perpendicular to the axis.

Divisions marked on the upper quarters of the base ring, commencing where it would be intersected by a plane parallel to the axis of the piece, and tangent to the upper surface of the trunnions.

For giving elevations up to three degrees but especially for pointing a piece at a less elevation than the natural angle of sight.

An instrument having a graduated scale of tangents, by means of which any elevation may be given to a piece.

Guns and howitzers.

A MUZZLE-SIGHT of iron is screwed into the swell of the muzzle of guns, or into the middle of the muzzle-ring of howitzers. The height of this sight is equal to the dispart of the piece, so that a line joining the muzzle-sight and the pivot of the tangent scale is parallel to the axis of the piece.

An instrument made of sheet-brass; the lower part is cut in the form of a crescent, the points of which are made of steel; a small spirit-level is fastened to one side of the plate, parallel to the line joining the points of the crescent, and a slider is fastened to the same side of the plate, perpendicular to the axis of the level.

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