Part 101
=Plongée.= In artillery and fortification, means a slope toward the front. Thus, in speaking of the course of a shell through the air, its plongée is from the point of greatest altitude to the point at which it strikes the earth. So, in fortification, the plongée is the top of the parapet, sloping gently toward the front. This depression varies from one-fourth to one-sixth of the thickness of the parapet.
=Ploy.= To form a column from a line of battle on some designated subdivision.
=Ployments.= A general term for all tactical movements by which a column is formed from line upon a designated subdivision.
=Pluck.= Spirit; perseverance under opposition or discouragement; indomitableness; courage.
=Plume.= A large and handsome feather worn as an ornament on a helmet, on a military hat, and the like.
=Plummet.= In gunnery, is a simple line and bob for pointing mortars. A plummet is also used for regulating the march of infantry. It is made by means of a musket-ball, suspended by a silk string, upon which the required lengths are marked; the length is measured from the point of suspension to the centre of the ball. The different lengths of these plummets are as follows: for common time, 90 steps in a minute, 17.37 inches; quick time, 110 steps in a minute, 11.6 inches; double time, 165 steps in a minute, 5.17 inches.
=Plunder.= To take the goods of another by force; to take from by robbery; to spoil; to strip; to rob; as, to plunder a place. Also to take by pillage or open force; as, the enemy plundered all the goods they found.
=Plunder.= That which is taken from an enemy; pillage; spoil.
=Plunging Fire.= See FIRE, PLUNGING.
=Pluteus.= A kind of wicker helmet covered with raw ox-hide, worn by the ancient Greeks when engaged in sapping walls. Others were made of hurdles, covered in the same way, running upon three wheels, and affording cover to 7 or 8 miners.
=Plymouth.= A seaport town in England, county of Devon, on the east side of a peninsula, between the rivers Plym and Tamar, at the head of Plymouth Sound, 37 miles southwest of Exeter. Prior to the time of the Norman conquest it was called _South Town_, or _Sutton_; under the Saxon dynasty it was called _Tamerweorth_. The growing prosperity of the town excited the jealousy of France; and in 1339 a force from thence landed, and attempted to burn it. They succeeded in burning a portion, but were ultimately repulsed, with the loss of 500 men, by Hugh Courtenay, earl of Devon, aided by a number of “knights and men of the countrie.” A similar attempt was made in 1377, but with no great result; and after each, the fortifications were extended and strengthened. In 1335 the Black Prince embarked from Plymouth for France, and on his return to England he landed here with his prisoner, King John of France, who had been captured at the famous battle of Poitiers. During the civil war between Charles I. and the Parliament, Plymouth was held by the troops of the latter party, who, though besieged, and almost reduced by famine, resisted for three years every effort of the royalists. After the restoration the citadel was erected, and in the reign of William III. the dock-yard and the naval arsenal were established toward the west, upon the eastern shore of Hamoaze.
=Plymouth.= A town of Washington Co., N. C., on the south bank of Roanoke River about 8 miles from its mouth, where it empties into Albemarle Sound. During the civil war it was held for some time by the Union troops as a key to the river, and was strongly fortified. On April 17, 1864, a Confederate force under Gen. Hoke attacked this place, and after four days’ severe fighting, being five times repulsed with great slaughter, succeeded in capturing it, by the powerful assistance of an ironclad ram and a floating sharpshooter battery.
=Pocket Ledger.= In the British service, is a small book in the possession of each soldier, containing the result of the monthly settlement of pay, the state of his savings-bank account, the date of his enlistment, his services, wounds, decorations, date of birth, next of kin, a summary of the regulations which affect him, and many other useful particulars.
=Podoll= (Bohemia). The site of a severe conflict between the Austrians and a part of the army of Prince Frederick Charles of Prussia, June 26, 1866, in which the latter had the advantage.
=Point.= In heraldry, a triangular figure issuing from the dexter and sinister base of the shield. It is common in French and German heraldry, and occurs in the shield of Hanover, which was a part of the royal arms of Great Britain from the accession of George I. till that of the present sovereign. A shield charged with a point is in heraldic drawing hardly distinguishable from one parted per chevron.
=Point d’Appui.= Any particular given point or body, upon which troops are formed, or by which they are marched, in line or column. _Points d’appui_ also signify the different advantageous posts, such as castles, fortified villages, etc., which the general of an army takes possession of in order to secure his natural position.
=Point of Alignment.= The point which troops form upon and dress by.
=Point of Formation.= A point taken, upon which troops are formed in military order.
_Perpendicular points_, the points upon which troops march in a straight-forward direction.
_Relative points_, the points by which the parallelism of a march is preserved.
=Point of Honor.= See HONOR, POINT OF.
=Point of War.= A loud and impressive beat of the drum, the perfect execution of which requires great skill and activity. The point of war is beat when a battalion charges.
=Point-blank.= The second point at which the line of sight intersects the trajectory of a projectile. See POINTING.
=Point-blank.= Directed in a line toward the object aimed at; aimed directly toward the mark.
=Point-blank Range.= Is the distance from the muzzle of the piece to that point in a projectile’s trajectory where it cuts the prolongation of the natural line of sight, a second time, the natural line of sight being horizontal. The British define point-blank range as, “the distance from the muzzle to the first graze when the axis of the piece is parallel to the horizontal plane upon which the carriage stands.” This definition is being adopted in the U. S. service.--See POINTING.
=Point-blank Shot.= The shot of a gun pointed directly toward the object to be hit.
=Pointing.= To point or aim a fire-arm is, to give it such direction and elevation that the projectile shall strike the object.
_Definitions._--The _axis of the piece_ is the centre line of the bore.
The _line of fire_ is the axis of the piece prolonged.
The _plane of fire_ is a vertical plane through the line of fire.
The _line of sight_ is the right line from the eye to the object to be hit, passing through the front and rear sights.
The _plane of sight_ is a vertical plane through the line of sight.
The _angle of sight_, or the _elevation_, is the vertical angle included between the line of sight and the plane containing the axis of the piece and a horizontal line at right angles to it.
The _natural line of sight_ is the line of sight nearest to the axis of the piece. In guns without rear sights it is the right line through the highest point of the base-ring and swell of the muzzle or top of the front sight when there is one. It is sometimes called the _line of metal_, as in mortars. For convenience and accuracy the _natural line of sight_ is usually parallel to the axis of the piece. When special breech-sights are used, it passes through the zero of the scale, which in the _pendulum hausse_ and other vibrating scales coincides with the axis of vibration. All other lines of sight are called _artificial lines of sight_.
_Point-blank_, in small-arms, is the second point in which the natural line of sight (when horizontal) cuts the trajectory. In artillery, it is the point where the projectile first strikes the horizontal plane on which the gun stands, the axis of the piece being horizontal.
_Pointing Guns and Howitzers._--In pointing old model guns and howitzers under ordinary angles of elevation, the piece is first directed toward the object, and then elevated to suit the distance. The accuracy of the aim depends: (1) On the fact that the object is situated in the plane of sight; (2) That the projectile moves in the plane of fire, and that the planes of sight and fire coincide, or are parallel and near to each other; and (3) On the accuracy of the elevation. The first of these conditions depends on the eye of the gunner, and the accuracy and delicacy of the sights; the errors under this head are of but little practical importance. When the trunnions of the piece are horizontal, and the sights are properly placed on the surface of the piece, the planes of sight and fire will coincide; but when the axis of the trunnions is inclined, and the natural line of sight is oblique to the axis of the bore, the planes are neither parallel nor coincident, but will intersect at a short distance from the muzzle, and the aim will be incorrect. If the natural line of sight be made parallel to the line of fire, by making the height of the front sight equal to the dispart of the piece, the planes of sight and fire will be parallel. Field-guns of the present day have special breech-sights or pendulum-sights. The zero of the scale and top of front sight are in a line parallel to the axis of the piece, and in pendulum-sights this zero coincides with the pivot at which the scale vibrates. Siege and sea-coast cannon are generally fired from fixed platforms, which renders the axis of the trunnions horizontal; they are, therefore, not furnished with pendulum-sights, but usually with breech-sights set in sockets at the breech. In the absence of a breech-sight the piece can be pointed with a natural line of sight so as to strike objects not situated at point-blank distance. Owing to the shape and size of the reinforce of sea-coast cannon, the natural line of sight is formed by affixing a front sight to the muzzle, or to a projection cast on the piece between the trunnions. Although the latter arrangement does not give quite so long a distance between the sights as is desirable, it permits the use of a shorter breech-sight, and the front sight does not interfere with the roof of the embrasure, when the piece is fired under high elevation.
_Errors in Pointing._--When the platform or ground upon which the gun stands is not level there is an error in pointing (except when compensating sights such as the _pendulum hausse_ are used), which varies in direction with the circumstances of the pointing and in amount with the elevation of the piece.
If the _natural line of sight_ is pointed upon the object and the elevation then given by a gunner’s quadrant or other device, the shot will go to the side of the lower wheel. If the gun be depressed, it will go to the side of the upper wheel.
If the _tangent scale_ or old pattern _breech-sight_ is used with the ordinary fixed muzzle-sight, and it be placed on a chalk-mark just determined, the shot will fall on the side of the upper wheel. If the scale is placed on the permanent mark, the contrary will hold.
If a _socket or fixed breech-sight_ is used, the shot will fall on the lower or upper side according as the gun is elevated or depressed.
_Pointing Mortars._--In pointing mortars, the piece is first given the elevation, and then the direction necessary to attain the object. Mortars are generally fired from behind epaulements, which screen the object from the eye of the gunner. The elevation is first given by a gunner’s quadrant, and the direction is given by moving the mortar-bed with a handspike, so as to bring the line of metal into the plane of sight, which passes through the object and the centre of the platform. The plane of sight may be determined in several ways; the method prescribed is to plant two stakes, one on the crest of the epaulement, and the other a little in advance of the first, so that the two shall be in a line with the object, and the gunner standing in the middle of the rear edge of the platform; a cord is attached to the second stake and held so as to touch the first stake; a third stake is driven in a line with the cord, in rear of the platform, and a plummet is attached to this cord so as to fall a little in rear of the mortar. The cord and plummet determine the required plane of sight into which the line of metal of the mortar must be brought. With the 13-inch mortar mounted upon centre-pintle chassis, the plane of sight must be so determined as to pass through the pintle to obtain perfect accuracy. One of the best methods of pointing mortars so mounted, is to place on the crest of the parapet in line with the axis of the platform a goniometer, the alidade of which can be directed upon the object,--the angle is read from the vertical plane containing the axis of the platform. The traverse circle is similarly graduated from the axis of the platform. A pointer attached to the chassis enables the gunner to lay the mortar very nearly in the vertical plane passing through the object,--the error being the perpendicular distance from the pintle to the plane of sight. This is the method of Lieut. A. B. Dyer, 4th U. S. Artillery. Gen. Abbot of the U. S. Engineer Corps used a similar principle during the late war, 1861-65. The usual angle of fire of mortars is 45°, which corresponds nearly with the maximum range. The advantages of the angle of greatest range are: (1) Economy of powder; (2) Diminished recoil, and strain on the piece, bed, and platform; (3) More uniform ranges. When the distance is not great, and the object is to penetrate the roofs of magazines, buildings, etc., the force of fall may be increased by firing under an angle of 60°. The ranges obtained under an angle of 60° are about _one-tenth_ less than those obtained with an angle of 45°. If the object be to produce effect by the bursting of the projectile, the penetration should be diminished by firing under an angle of 30°. When the object is not on a level with the piece, the angle of greatest range is considered in practice to be 45° increased or diminished by one-half the angle of elevation or depression of the object. The angle of fire being fixed at 45° for objects on the same level with the piece, the range is varied by varying the charge of powder. Stone-mortars are pointed in the same manner as common mortars; the angle of fire for stones is from 60° to 72°, in order that they may have great force in falling; the angle for grenades is about 33°, in order that their bursting effect may not be destroyed by their penetration into the earth.
_Night-firing._--Cannon are pointed at night by means of certain marks, or measurements, on the carriage and platform, which are accurately determined during the day.
_Pointing Small-arms._--The rear-sights of small-arms are graduated with elevation marks for certain distances, generally every hundred yards; in aiming with these as with all other arms, it is first necessary to know the distance of the object. This being known and the slider being placed opposite the mark corresponding to this distance, the bottom of the rear-sight notch, and the top of the front-sight, are brought into a line joining the object and the eye of the marksman. The term _coarse-sight_ is used when a considerable portion of the front-sight is seen above the bottom of the rear-sight notch; and the term _fine-sight_, when but a small portion of it is seen. The graduation marks being determined for a fine-sight, the effect of a coarse-sight is to increase the true range of the projectile.
_Graduation of Rear-sights._--If the form of the trajectory be known, the rear-sight of a fire-arm can be graduated by calculation; the more accurate and reliable method, however, is by trial.
_Distance of Objects._--Various instruments have been devised to determine the distance of objects, based on the measurement of the visual angles subtended by a foot or cavalry soldier, of mean height, at different distances, and upon other principles. (See RANGE-FINDER.) The range being known, the proper elevation (or charge of powder in mortars) and length of fuze is given by tables of fire obtained from calculation or experiment. The ranges for guns of position are determined by thorough surveys of the surrounding country or harbor channels, by which the distances of all prominent points in the route of an approaching enemy are fixed beforehand. The ranges in field artillery are usually obtained by trial shots at the enemy. For small-arm and field-gun firing, the importance of at once getting the range cannot be overvalued; hence the importance of _estimating distances_ without instrumental aid. The soldier is guided by his experience of aerial perspective, by the apparent size of known objects, and numerous other aids too delicate for enunciation. The art can be acquired to a high degree of perfection by _practice_, which now forms a very important part of the soldier’s training.
=Pointing-board.= See BOARD, POINTING.
=Pointing-cord.= Cord used in pointing mortars (which see). See POINTING-STAKES.
=Pointing-rings.= See ORDNANCE.
=Pointing-stakes.= Are used in pointing mortars, and by them one of the fixed points is established upon the crest of the parapet or at the foot of the interior slope, and another in rear of the piece. Then by a cord called the _pointing-cord_, stretched between these two points, with the plummet suspended from it, a vertical plane is determined with which the line of metal is made to coincide. Mortars are also pointed by means of _pointing-wires_.
=Pointing-wires.= Are wires which are used in directing mortars. The two fixed points required in directing a mortar are determined by planting two wires upon the epaulement, one upon its crest, and the other about a yard in advance of it, both as nearly as possible in the vertical plane passing through the centre of the platform and the object. The points being thus established, the direction is thus given to the mortar, by causing a plummet held in rear of it to cover the wires and the line of metal. This method is defective both in accuracy of aim and the liability of the wires being deranged by the shots of the enemy or by other causes.
=Points of Passing.= The ground on which one or more bodies of armed men march by a reviewing general.
=Points of the Escutcheon.= In heraldry, in order to facilitate the description of a coat of arms, it is the practice to suppose the shield to be divided into nine points, which are known by the following names: The dexter chief point, the middle chief, the sinister chief, the collar, or honor point, the fess point, the nombril, or navel point, the dexter base point, the middle base point, and the sinister base point. The dexter and sinister sides of the shield are so called, not in relation to the eye of the spectator, but from the right and left sides of the supposed bearer of the shield.
=Poitiers=, or =Poictiers=. A town of France, capital of the department of Vienne, on the Clain, 58 miles south-southwest of Tours. In the vicinity of Poitiers, Alaric II., the Visigoth, was defeated and slain by Clovis in 507. Somewhere between Poitiers and Tours a great battle took place on October 10, 732, between the Franks under Charles Martel and the Saracens under Abder-Rahman. The Saracens were routed with enormous slaughter,--357,000 of them (according to one old chronicler, and supposed to be exaggerated) being left dead on the field. Near here was fought the battle between Edward the Black Prince and John, king of France, September 19, 1356, in which Edward, with some 12,000 or 14,000 Englishmen and Gascons, defeated 60,000 of the troops of King John, and took the monarch himself and one of his sons prisoners. See TOURS.
=Poitou.= A former province of Western France, now mainly comprised in the departments of Deux Sèvres, Vendée, and Vienne. It became an English possession in 1152. In 1204, Philip Augustus regained it by conquest from England, and in 1295 it was formally ceded to France. It again reverted to England in 1360 by the peace of Bretigny, but was retaken by Charles V., and incorporated with the French crown.
=Poitrel= (_Fr._). Armor for the breast of a horse.
=Pokanokets.= See MASSACHUSETTS INDIANS.