Eagle. In heraldry, is used as an emblem of magnanimity and fortitude. In the Roman armies the eagle was used as a military standard, and even previous to that time the Persians under Cyrus the Younger used the same military emblem. In modern times, France, Russia, Prussia, Austria, and the United States have adopted the eagle as a national military symbol. The Austrian eagle is represented as double-headed.

Eagle, Black. A Prussian order of knighthood, founded in 1701; united with the order of the Red Eagle, or order of Sincerity, instituted by the margraves of Bayreuth.

Earl Marshal. Of England, is one of the officers of state; is the head of the college of arms, which has jurisdiction in descents and pedigrees; determines all rival claims to arms; and he grants armorial-bearings, through the medium of the kings-of-arms, to parties not possessed of hereditary arms.

Early Cannon. See Ordnance, History of.

Earth-bag. See Bags.

Earth-house, or Eird-house. The name generally given throughout Ireland and Scotland to the underground buildings (which in some places are called also “Picts’ houses”) which served to hide a few people and their goods in time of war. The earth-house is a single irregularly-shaped chamber, from 4 to 10 feet in width, from 20 to 60 feet in length, and from 4 to 7 feet in height, built of unhewn and uncemented stones roofed by unhewn flags, and entered from near the top by a rude doorway, so low and narrow that only one man can slide down through it at a time. Implements of various kinds have been found in them,—such as bronze swords, gold rings, etc.

Earthworks. In fortification, is a general name for all military constructions, whether for attack or defense, in which the material employed is chiefly earth.

East Indian Army. In 1861 the British Secretary of State for India brought forward a measure for reorganizing the Indian army, which has been passed into a law. The British portion of the Indian army is to form part of the queen’s army generally, with certain honorary distinctions, and is to take its turn at home and in the colonies like the rest; but the expenses are to be paid out of Indian, not Imperial revenues. The native portion is to be wholly in India; in its reconstruction many improvements are made to lessen the chances of future revolt.

Ebersberg, or Ebelsberg. A town of Upper Austria, on the Traun, 8 miles northwest from Ens, remarkable for being the scene of the defeat of the Austrians by the French in 1809.

Eboulement (Fr.). The crumbling or falling of the walls of a fortification.

Ebro. A river in Spain, the scene of a signal defeat of the Spaniards by the French under Lannes, near Tudela, November 23, 1808; and also of several important movements of the allied British and Spanish armies during the Peninsular war (1809-13).

Eccentric. A device applied to the truck wheels of top carriages and beds of mortars in sea-coast artillery to give either rolling or sliding friction at will. The wheels turn on axle-arms which project eccentrically from the ends of an axle passing through both cheeks; when the axle is turned the axle-arms carry the wheels up or down; when at the lowest point the weight of the carriage is borne by the wheels, and the system moves on rolling friction; the wheels are then said to be in gear; when out of gear, or at their highest points, the wheels do not touch the rails or platform plates, but the cheeks rest on them, and the carriage moves upon sliding friction. A similar device is attached to the chassis near the pintle to enable it to be readily traversed when in gear, and give it stability when out of gear.

Eccentric Projectiles. A spherical projectile in which the centre of inertia does not coincide with the centre of figure. Such projectiles are subject to great deviations, which can be predicted as to direction by knowing the position of the centre of inertia of the shot in the bore of the gun. (See Projectiles, Deviation of.) The side of the ball upon which the centre of inertia lies can be found by floating it in a bath of mercury, and marking the highest point where it comes to a state of rest; the centre of inertia lies nearest the opposite side; its exact position is determined by a kind of balance called the eccentrometer; the ball is placed in the balance with the marked point nearest the fulcrum; the distance of the centre of inertia or gravity from the fulcrum is obtained by dividing the product of the counterbalancing weight and its distance from the fulcrum by the weight of the projectile.

Echarge, Feu, or Feu d’Echarge. Is employed to signify that a column of troops is struck at a very oblique angle.

Echaugette. In military history, signifies a watch-tower, or kind of sentry-box.

Echelon. A military term applied to a certain arrangement of troops when several divisions are drawn up in parallel lines, each to the right or the left of the one preceding it, like “steps,” or the rounds of a ladder, so that no two are on the same alignment. Each division by marching directly forward can form a line with that which is in advance of it. There are two sorts of echelon, direct and oblique, the former of which is used in an attack or retreat.

EckmÜhl, or EggmÜhl. A small village of Bavaria, on the Great Laber. This place is celebrated for the important victory gained by the French over the Austrians on April 22, 1809, and which obtained for Davoust the title of Prince of EckmÜhl.

Eclaireurs (Fr.). A corps of grenadiers raised by Bonaparte in France, who from their celerity of movements were compared to lightning.

Eclopes (Fr.). A military term to express those soldiers who, though invalids, are well enough to follow the army. Among these may be classed dragoons or horsemen whose horses become lame and cannot keep up with the troop or squadron. They always march in the rear of a column.

Ecole Polytechnique. A celebrated military school in Paris, established in 1794, chiefly for the artillery service. The examinations for the schools are public to all France. It not only furnishes officers of artillery, but also civil and military engineers of every description. The pupils of this school defended Paris in 1814 and 1830.

Economy. In a military sense, implies the minutiÆ or interior regulations of a regiment, troop, or company. Hence regimental economy.

Ecorcheurs (Flayers). A name given to bands of armed adventurers who desolated France and Belgium during the 15th century, beginning about 1435, and they at one time numbered 100,000. They are said to have stripped their victims to their shirts, and flayed the cattle. They were favored by the English invasion and the civil wars.

Ecoutes. Small galleries made at equal distances in front of the glacis of the fortifications of a place. They serve to annoy the enemy’s miners, and to interrupt them in their work.

Ecreter (Fr.). To batter or fire at the top of a wall, redoubt, epaulement, etc., so as to dislodge or drive away the men that may be stationed behind it, in order to render the approach more easy. Ecreter les pointes des palissades is to blunt the sharp ends of the palisades. This ought always to be done before you attack the covert way, which is generally fenced by them.

Ecu (Fr.). A large shield which was used by the ancients, and carried on their left arm, to ward off the blows of sword or sabre. This instrument of defense was originally invented by the Samnites. The Moors had ecus, or shields, sufficiently large to cover the whole of their bodies. The clipei of the Romans only differed from the ecu in shape; the former being entirely round, and the latter oval.

Ecuador, or Equator. A South American republic, founded in 1831, when the Colombian republic was divided into three; the other two being Venezuela and New Granada. Gen. Franco was here defeated in battle by Gen. Flores, August, 1860. Several insurrections have taken place in Ecuador since 1860.

Edessa, or Callinhoe. An ancient city of Mesopotamia. In 1144 the Edessenes were defeated by the Saracen chief Nur-ed-deen, and all who were not massacred were sold as slaves. After many vicissitudes, it fell successively into the hands of the sultans of Egypt, the Byzantines, the Mongols, Turkomans, and Persians; the city was finally conquered by the Turks, and has ever since formed a portion of the Turkish dominion. Its modern name is Oorfa.

Edge. The thin or cutting part of a sword or sabre.

Edgehill. An elevated ridge in Warwickshire, England, 7 miles northeast from Banbury. Here was fought, on Sunday, October 23, 1642, the first great battle of the civil war, between the royalist forces under Charles I. and the Parliamentarians under the Earl of Essex. Prince Rupert, who led the right wing, charged with his cavalry the left wing of the Parliamentarians, broke it, and pursued it madly to Keinton. Essex with his force defeated the right wing of the royalists.

Edinburgh. The metropolis of Scotland, situated about 1¹/₂ miles from the Firth of Forth. It was taken by the Anglo-Saxons in 482; retaken by the Picts in 695; city fortified and castle rebuilt, 1074; besieged by Donald Bane, 1093. The city was taken by the English in 1296; surrendered to Edward III. in 1356. It was burnt by Richard II., 1385, and by Henry IV., 1401. A British force landed from a fleet of 200 ships, in 1544, and burned Edinburgh. The castle surrendered to Cromwell in 1650. The young Pretender occupied Holyrood September 17, 1745, and the battle of Preston Pans took place September 21, 1745.

Effective. Fit for service; as, an army of 30,000 effective (fighting) men.

Efficient. A thoroughly trained and capable soldier. It is also a term used in connection with the volunteers. A volunteer is said to be efficient when he has performed the appointed number of drills and fired the regular number of rounds at the target, in the course of the year.

Egham. A village in the northwest of Surrey, 18 miles west of London. In the vicinity is Runnymede, a meadow on the Thames, where King John conferred with his barons before signing the Magna Charta in 1215.

Egypt. A country in Northeast Africa. On the division of the Roman empire (395 A.D.) Egypt became a part of the dominions of Arcadius, ruler of the Eastern empire. But, owing to religious feuds of the Jacobites and Melchites, it became a province of Persia (616) for twelve years. In 640 the governor, Makaukas, endeavored to make himself independent, and invited the arms of the Arabs, and Amrou easily conquered Egypt. Although Alexandria was retaken by Constantine III., the Arabs drove him out and maintained their conquest, and Egypt remained an appendage of the caliphate. It afterwards passed into the dynasty of the Turks, and was administered by pashas. Constant rebellions of the Mamelukes, and the violence of contending factions, distracted the country for more than two centuries. The most remarkable event of this period was the French invasion by Bonaparte in 1798, which, by the conquest of Alexandria and the battle of the Pyramids against the Mamelukes, led to the entire subjection of the country, from which the French were finally expelled by the Turks and British in 1801, and the country restored to the Ottoman Porte. The rise of Mohammed Ali in 1806 imparted a galvanic prosperity to Egypt by the destruction of the Mamelukes, the formation of a regular army, and the introduction of European civilization. He considerably extended its boundaries, even into Asia; but in 1840 he was dispossessed of his Asiatic conquests. The treaty of London, however, in 1841, confirmed the viceroyalty of Egypt as a fief of the Ottoman empire to him and his descendants.

Ehrenbreitstein. A town and fortress of Rhenish Prussia, situated on the right bank of the Rhine, directly opposite Coblentz, with which it is connected by a bridge of boats. The fortress of Ehrenbreitstein occupies the summit of a precipitous rock 490 feet high, and has been called the Gibraltar of the Rhine, on account of its great natural strength and its superior works. It is capable of accommodating a garrison of 14,000 men, and provisions for 8000 men for ten years can be stowed in its vast magazines. Ehrenbreitstein was besieged in vain by the French in 1688, but fell into their hands in 1799, after a siege of fourteen months. Two years after, the French, on leaving, at the peace of LunÉville, blew up the works. It was assigned, however, to Prussia by the Congress of Vienna in 1814, and under that country was restored and thoroughly fortified. It is now one of the strongest forts in Europe.

Eighty-ton Gun. A large Woolwich gun designed as an armament for the “Inflexible.” Its construction was authorized in March, 1874, and the gun was ready for proof in October, 1875. When first made it weighed 81 tons, having a caliber of 14¹/₂ inches. It was bored during the progress of the experiments to 16 inches, and was given an enlarged chamber. The experiments were conducted by the celebrated “Committee on Explosion.” See Ordnance, Recent History of.

Eilau-Preussisch. A town of Prussia, government of KÖnigsberg. It is chiefly celebrated for the victory gained there by the French over the united Prussian and Russian armies, February 8, 1807.

Einsiedeln. A small town of Switzerland, in the canton of Schwytz. It contains a fine abbey, which was rifled by the French in 1798.

Ejector. The device used in breech-loading small-arms to throw out the metallic cartridge-case after it is fired.

Ejector Spring. The spring which operates an ejector.

El Arish. A village of Lower Egypt on the Mediterranean, on the route from Egypt to Syria. It is but little more than a fort and a few houses, and was taken by the French in 1799; and here the French general Kleber signed, in 1800, a convention with Sir Sydney Smith, engaging to leave Egypt with his troops.

Elath, or Eloth. A seaport situated at the head of that gulf of the Red Sea, to which it gave its name. It was a fortified port in the time of Solomon; revolted against Joram; was retaken by Azariah; and was eventually conquered by Rezui, and held by the Syrians till it became a Roman frontier town. Under the Mohammedan rule it rose for a while to some importance, but has now sunk into insignificance.

Elba. An island belonging to the kingdom of Italy, in the Mediterranean Sea, between Corsica and the coast of Tuscany, from the latter of which it is separated by a channel 5 miles in breadth. Elba has been rendered famous in history from having been Napoleon’s place of exile from May, 1814, till February, 1815.

El Boden. A mountain-range, near Ciudad Rodrigo, in Spain, where the British troops distinguished themselves against an overwhelming French force in 1811.

Elbow-gauntlet. An ancient piece of armor, a gauntlet of plate reaching to the elbow, adopted from the Asiatics in the 16th century.

Elbow-piece. An ancient piece of armor, a metal plate used to cover the junction of the rere-brace and rant-brace, by which the upper and lower half of the arm were covered.

Elchingen. A village of Bavaria, on the Danube, 7 miles northeast from Ulm. Here the Austrians were defeated by the French in 1805. For this victory Marshal Ney received the title of Duke of Elchingen.

Electric light. An intense light produced by passing an electric current between points of carbon forming electrodes of the circuit. There are many forms of the apparatus. It will be extensively used in future wars for lighting harbor channels, approaches to forts, etc.

Elements. In a military sense, signify the first principles of tactics, fortification, and gunnery.

Elephant. See Pack and Draught Animals.

Elevate, To. Is to raise the muzzle of the cannon or rifle so that the latter shall be directed at a point above that which it is intended shall be struck.

Elevating Arc. In gunnery, is an arc attached to the base of the breech parallel to the ratchets and graduated into degrees and parts of a degree. A pointer attached to the fulcrum points to the zero of the scale when the axis of the piece is horizontal. Elevations and depressions are indicated by the scale. Besides the graduations on the arc, the ranges (in yards) and charges for shot and shell are given.

Elevating Bar. An iron bar used in elevating guns or mortars having ratchets at the breech.

Elevating Screw. The screw by means of which the breech of a cannon is raised, the result being to depress the muzzle.

Elevating Sight. See Sight, Elevating.

Elevation. In gunnery, is one of the elements of pointing, being the movement of the axis of a piece in a vertical plane as distinguished from direction or its movement horizontally. The elevation is usually positive,—that is, the gun is pointed above the horizontal. When it is pointed below, it is said to be depressed. The word is also used to express degree, or as a synonym for angle of elevation. The sights or elevating apparatus of guns are graduated on the theory that the object is in the horizontal plane of the piece, or that the line of sight is horizontal, which is not always the case in practice. When the elevation is determined by sights the angle of elevation is the angle between the line of sight and the axis of the piece, when these lines are in the same vertical plane,—or the angle between the line of sight and a plane containing the axis of the piece and a horizontal line intersecting it at right angles, when they are not. The graduations of tangent scales and fixed breech-sights give this angle in degrees. The graduation of the pendulum hausse gives the angle correctly only when the line of sight is horizontal. When the elevation is given by elevating arcs or gunner’s quadrant, the angle of elevation becomes the angle of fire, or the angle which the axis of the piece makes with the horizontal. Elevation is necessary to overcome the effect of gravity on the projectile. The degree of elevation increases with the range. In vacuo the elevation corresponding to the maximum range is 45°. In the air the angle of maximum range diminishes with the velocity and increases with diameter and density of the ball. It is greater in mortars than in howitzers, and greater in howitzers than in guns. In mortars it approximates to 42°; in guns it is about 37°.

Ellisburgh. A village of Jefferson Co., N. Y. In 1814 an engagement took place here between the Americans and British, in which the latter were defeated.

Elmina. A fortified town and seaport of West Africa, founded by the Portuguese in 1481; was the first European settlement planted on the coast of Guinea. It was taken by the Dutch in 1637, and was ceded by them to Portugal. It was burned by the British troops in 1873.

Elsass (Fr. Alsace). One of the old German provinces, having the Rhine on the east and the Vosges Mountains on the west. It was ceded to France in 1648; but after the Franco-German war was annexed by Prussia, under treaty of May 10, 1871.

Elswick Compressor. An arrangement for compressing friction plates used in the English navy to take up the recoil of gun-carriages upon their slides. The 7 friction plates arranged longitudinally under the carriage and attached to its lower part, have alternating between them 6 long flat bars attached at their ends to the slide by bolts passing through them, but allowing them a side motion. The plates and bars are tightly clamped by short rocking levers, the lower ends of which act on the outside plates. The levers are worked by collars on a threaded shaft, which catch their upper ends. The shaft is called the compressor shaft, and has a handle or crank on the outside of each cheek or bracket,—one is called the adjusting lever, the other the compressor lever. The first is used to give an initial compression to suit the charge, the other is operated by the recoil being forced down by a tripper on the slide. Two forms of the compressor are used,—one for the single plate, the other for the double-plate carriage. In the double-plate carriage the adjusting lever can be set to any degree of compression without causing any motion in the compressor shaft or lever.

Elswick Gun. Armstrong gun (which see).

Elvas. A strong frontier town of Portugal, in the province of Alemtejo, situated on a rocky hill, 10 miles northwest from Badajos. It is one of the most important strongholds in Europe. The arsenal and bomb-proof barracks are capable of containing 6000 or 7000 men. In 1808 it was taken and held for five months by the French.

Emaum Ghaur. In Scinde, was a strong fortress in the Thur or Great Sandy Desert, separating that province from the rajpoot state of Jessulmere. It was captured by Sir Charles Napier in January, 1843.

Embark. To put or cause to go on board a vessel or boat; as, to embark troops. To go on board of a ship, boat, or vessel; as, the troops embarked for Egypt.

Embarkation. The act of putting or going on board of a vessel.

Embaterion. A war-song of the Spartans, accompanied by flutes, which they sung marching in time, and rushing on the enemy. The origin of the embaterion is lost in antiquity.

Embattle. To arrange in order of battle; to draw up in array, as troops for battle; also, to prepare or arm for battle.

Embattle. To furnish with battlements. “Embattled” house.

Embattlement. An indented parapet; battlement.

Embezzlement. See Appendix, Articles of War, 60.

Emblazonry. See Blazonry.

Emblee (Fr.). A prompt, sudden, and vigorous attack, which is made against the covert way and outworks of a fortified place.

Embody. To form or collect into a body or united mass; as, to embody troops.

Embrasseur (Fr.). A piece of iron, which grasps the trunnions of a piece of ordnance, when it is raised upon the boring machine, to widen its caliber.

Embrasure. In fortification, is an opening in the parapet, or a hole in the mask wall of a casemate through which the guns are pointed. The sole or bottom of the embrasure is from 2¹/₂ to 4 feet (according to the size of the gun) above the platform upon which the gun stands. Parapet embrasures are smallest at the interior opening, which is called the mouth, and is from 1¹/₂ to 2 feet wide. The widening of the embrasure is what is called the splay. The sole slopes downward about one in six. Its exterior line, or its intersection with the exterior slope, is usually made half the length of the sole. The line which bisects the sole is called the directrix. The sides are called cheeks. The masses of earth between embrasures are called merlons. When the directrix makes an angle with the direction of the parapet, the embrasure is oblique. The embrasures of casemates have in horizontal section a shape something like an hour-glass. The nearest part is called the throat. This is sometimes closed with iron shutters.

Embrocher. A vulgar term used among French soldiers to signify the act of running a man through the body; literally to spit him.

Emery. A powder made by grinding a mineral,—corundum,—used by soldiers for cleaning their arms.

Eminence. A high or rising ground, which overlooks and commands the low places about it. Such places, within cannon-shot of any fortified place, are a great disadvantage, if the besiegers become masters of them.

Emir, or Emeer. An Arabic word, equivalent to “ruler,” is a title given to all independent chieftains, and also to all the actual or supposed descendants of Mohammed through his daughter Fatima. In former times, the title of Emir was borne by the leaders in the religious wars of the Mohammedans, and by several ruling families.

Emissary. A person sent by any power that is at war with another, for the purpose of creating disaffection among the people of the latter.

Emousser (Fr.). To blunt, to dull. In a military sense, it signifies to take off the four corners of a battalion, which has formed a square, and to give it, by those means, an octagon figure; from the different obtuse angles of which it may fire in all directions.

Emperor (Imperator). Among the ancient Romans, signified the general of an army, who, for some extraordinary success, had been complimented with this appellation. Subsequently it came to denominate an absolute monarch or supreme commander of an empire. In Europe, the first who bore the title was Charlemagne.

Empilement (Fr.). From empiler, to pile up. The act of disposing shot and shell in the most secure and convenient manner. This generally occurs in arsenals and citadels.

Emprise. A hazardous attempt upon the enemy.

Encamp. To form and occupy a camp; to halt on a march, spread tents, and remain for a night or for a longer time; as, an army or company.

Encampment. The pitching of a camp. The act of pitching huts or tents, as by an army, for temporary lodging, or rest; the place where an army or company is encamped. There are intrenched camps, where an army is intended to be kept some time, protected against the enemy; flying camps, for brief occupation; camps of position, bearing relation to the strategy of the commander; and camps of instruction, to habituate the troops to the duties and fatigues of war.

Enceinte. In fortification, denotes generally the whole area of a fortified place. Properly, however, it means a cincture or girdle, and in this sense the enceinte signifies the principal wall or rampart encircling the place, comprising the curtain and bastions, and having the main ditch immediately outside it.

Encircle. To pass around, as in a circle; to go or come round; as, the army encircled the city.

Encombrer (Fr.). In fortification, to fill up any hollow place, such as a stagnant lake, etc., with rubbish.

Encompass. To describe a circle about; to go around; to encircle; to inclose; to environ; as, an army encompasses a city; a ship’s voyage encompasses the world.

Encounter. A meeting with hostile purpose; hence, a combat; a battle.

Encounter. To come against face to face; to engage in conflict with; to oppose; as, two armies encounter each other.

Encounters. In military affairs, are combats or fights between two persons only. Figuratively, battles or attacks by small or large armies.

Encroachments. The advancement of the troops of one nation on the rights or limits of another.

Enemy. In military language, the opposing force; as, “We have met the enemy, and they are ours.”

Enfans Perdus. Forlorn hope, in military history, are soldiers detached from several regiments, or otherwise appointed to give the first onset in battle, or in an attack upon the counterscarp, or the breach of a place besieged; so called (by the French) because of the imminent danger to which they are exposed.

Enfield Rifle-musket. The service arm of Great Britain prior to the adoption of breech-loaders; manufactured at Enfield, England, at the royal small-arms factories. It was first extensively introduced in 1853, and was used during the Crimean war. It had three grooves, with a twist of about one turn in 6 feet. Before the adoption of the Martini-Henry, large numbers of those guns were utilized by converting them into breech-loaders on the Snider principle. The Enfield rifles, though very serviceable weapons, much better than the Belgian and Austrian arms imported to the United States during the civil war, were in almost every respect inferior to the old Springfield (U.S.) rifle-musket, nearly of the same caliber (.58), the Enfield being .577. All those weapons have now given place to various breech-loading arms.

Enfilade. Is to fire in the direction of the length of a line of parapet or troops; to “rake it,” as the sailors say. In the siege of a fortress, the trenches of approach are cut in a zigzag, to prevent the defenders enfilading them from the walls.

Enfilading Batteries. In siege operations are one of the classes of batteries employed, the other classes being counter and breaching batteries. Enfilading batteries are located on the prolongation of the faces and flanks of the works besieged, to secure a raking fire along the terre-pleins.

Engage. To gain for service; to enlist.

Engage. To enter into conflict; to join battle; as, the armies engaged in a general battle.

Engagement. A general action or battle, whether by land or sea.

Engarrison. To protect any place by a garrison.

Engen. In Baden; here Moreau defeated the Austrians, May 3, 1800.

Enghien, or Steenkirk. In Southwestern Belgium. Here the British under William III. were defeated by the French under Marshal Luxemburg, July 24, 1692.

Engineer, Military. An officer in the service of a government, whose duties are principally to construct fortifications, to make surveys for warlike purposes, to facilitate the passage of an army by the construction of roads and bridges; in short, to execute all engineering works of a military nature. He is also called upon to undertake many works which more properly belong to the business of a civil engineer, such as the survey of the country, the inspection of public works, and, in short, all the duties of a government engineer.

Engineering. The business of the engineer; the art of designing and superintending the execution of railways, bridges, canals, harbors, docks, the defense of fortresses, etc.

Engineer Corps. In modern nations, the necessity for a corps of staff-officers, trained to arrange for and overcome the embarrassments of the movements of an army in the field, has been thoroughly demonstrated, and hence, in European armies, a trained staff of officers is organized for this purpose. In the United States a force of about 300 officers and enlisted men are engaged in these duties. See Sappers and Miners.

Engineers, Topographical. See Topographical Engineers.

England. The southern and larger division of the island of Great Britain, and the principal member of the United Kingdom of Great Britain and Ireland. It was so named, it is said, by Egbert, first king of the English, in a general council held at Winchester, 829. It was united with Wales, 1283; with Scotland in 1603; and Ireland was incorporated with them, January 1, 1801. For previous history, see Britain; and for further details of battles, etc., see separate articles.

Enlargement. The act of going or being allowed to go beyond the prescribed limits; as the extending the boundaries of an arrest, when the officer is said to be enlarged, or under arrest at large.

Enlargement. Enlargements of the bore and vent are injuries suffered by all cannon that are much used. The term is technically applied to certain injuries to brass cannon. See Injuries to Cannon.

Enlistment. The voluntary enrollment of men in the military or naval service.

Enniscorthy. A town of Ireland, in the county of Wexford, on the river Slaney. It arose in the Norman castle, still entire, founded by Raymond le Gros, one of the early Anglo-Norman invaders. Cromwell took this place in 1649; and the Irish rebels stormed and burned it in 1798.

Enniskillen. A town of Ireland, in the county of Fermanagh. This place is famous for the victory, in 1689, won by the troops of William III., under Lord Hamilton, over a superior force of James II., under Lord Gilmoy. The banners taken in the battle of the Boyne hang in the town-hall of Enniskillen.

Enniskillen Dragoons. A British regiment of horse; it was first instituted from the brave defenders of Enniskillen, in 1689.

Enrank. To place in ranks or in order.

Enroll. To place a man’s name on the roll or nominal list of a body of soldiers.

Ensconce. To cover as with a fort.

Enseigne (Fr.). The colors. The French designate all warlike symbols under the term enseigne; but they again distinguish that word by the appellations of drapeaux, colors, and etendards, standards. Drapeaux or colors are particularly characteristic of the infantry; etendards or standards belong to the cavalry.

Ensemble. Together; the exact execution of the same movements, performed in the same manner, and by the same motions. It is the union of all the men who compose a battalion, or several battalions or companies of infantry and cavalry, who are to act as if put in motion by the same spring.

Enshield. To cover from the enemy.

Ensiform. Having the shape of a sword.

Ensign-bearer. One who carries a flag; an ensign.

Ensigncy. The rank or office of an ensign.

Ensisheim. In Eastern France; here Turenne defeated the imperial army, and expelled it from Alsace, October 4, 1674.

Entanglement. Abatis, so called, when made by cutting only partly through the trunks, and pulling the upper parts to the ground, where they are picketed.

Entanglement, Wire. Formed by twisting wire round stout stakes or trees 7 feet apart. The wires are placed about a foot or 18 inches above the ground. The trees-pickets or trees are in two or three rows, arranged checkerwise, the wires crossing diagonally.

Enter, To. To engage in; to enlist in; as, to enter an army.

Enterprise. An undertaking attended with some hazard and danger.

Enterpriser. An officer who undertakes or engages in any important and hazardous design.

Entire, or Rank Entire. A line of men in one continued row by the side of each other. When behind each other, they are said to be in file.

Entonnoir (Fr.). The cavity or hole which remains after the explosion of a mine. It likewise meant the tin case or port-feu which is used to convey the priming powder into the vent of a cannon.

Entrench, To. Is to construct hastily thrown-up field-works for the purpose of strengthening a force in position. See Intrench.

EntrepÔts. Magazines and places appropriated in garrison towns for the reception of stores, etc.

Envelope. In fortification, a work of earth, sometimes in the form of a single parapet, and at others like a small rampart; it is raised sometimes in the ditch, and sometimes beyond it. Envelopes are occasionally en zigzag, to inclose a weak ground, where that is practicable, with single lines. Envelopes, in a ditch, are sometimes called sillons, contregardes, conserves, lunettes, etc.

Environ, To. To surround in a hostile manner; to hem in; to besiege.

Enzersdorf. A fortified town of Austria, 8 miles east from Vienna.

Epaule. In fortification, denotes the shoulder of a bastion, or the place where its face and flank meet and form the angle, called the angle of the shoulder.

Epaulement (Fr. epaule). In siege works, is a portion of a battery or earthwork. The siege batteries are generally shielded at one end at least by epaulements, forming an obtuse angle with the main line of the battery. The name is often given erroneously to the parapet of the battery itself, but it applies properly to the flanking return only. Sometimes the whole of a small or secondary earthwork, including the battery and its flanks, is called an epaulement; and sometimes the same name is given to an isolated breastwork intended to shield the cavalry employed in defending a body of besiegers.

Epaulette. A shoulder-knot worn by commissioned officers of the army and navy, as a mark of distinction. The insignia of their rank are usually marked on officers’ epaulettes.

Epauletted. Furnished with epaulettes.

Ephebi. In Grecian antiquity, the name given to the Attic youth from the age of 18, till they entered upon their 20th year. During this period they served a sort of apprenticeship in arms, and were frequently sent, under the name of peripoli, to some of the frontier towns of Attica to keep watch against foreign invasion.

EpibatÆ. In Grecian antiquity, the name given to soldiers whose duty it was to fight on board ship. They corresponded almost exactly to the marines of modern naval warfare. The term is sometimes found in Roman authors to denote the same class of soldiers, but the general phrase adopted by them is milites classiarii, or socii navales.

Epignare (Fr.). A small piece of ordnance which does not exceed one pound in caliber.

Epigoni. A term which signifies “heirs” or “descendants.” It was applied to the sons of the seven chiefs who conducted an expedition against Thebes to restore Polynices, and who were all killed except Adrastus. Ten years later the Epigoni—namely, AlcmÆon, Thersander, Diomedes, Ægialeus, Promachus, Sthenelus, and Euryalus—renewed the enterprise and took Thebes. The war of the Epigoni was celebrated by several ancient epic and dramatic poets.

Epinglette (Fr.). An iron needle with which the cartridge of any large piece of ordnance is pierced before it is primed.

Epinikian. Pertaining to, or celebrating, victory; as an epinikian ode.

Epirus. A celebrated country of ancient Greece, lying between the Ionian Sea and the chain of Pindus.

E Pluribus Unum. “One out of many.” A motto adopted by the United States since their declaration of independence, in 1776.

Epouvante (Fr.). A sudden panic with which troops are seized, and under which they retreat without any actual necessity for so doing.

Eprouvette (Fr.). A small mortar to prove the strength of gunpowder. There are different sorts of eprouvettes, according to the fancy of different nations who use them. Some raise a weight, and others throw a shot, to certain heights and distances. As a test of gunpowder the eprouvette is comparatively worthless, and it has been generally superseded by instruments for measuring the initial velocity obtained by firing the powder in the particular gun for which it is intended. A short mortar is, however, still used, to a certain extent, for testing the power of modern blasting powders, such as the mixtures of nitro-glycerine. A very small charge and a heavy shot of chilled iron which enters two or three inches only into the mortar are used. The square roots of the ranges (other things being equal) give the relative powers of the different powders, nearly.

Equalize. To render the distribution of any number of men equal as to the component parts. To equalize a battalion, to tell off a certain number of companies in such a manner that the several component parts shall consist of the same number of men.

Equation of Time. See Time, Mean Solar Time.

Equerry. Any person who is appointed to attend the sovereign, or prince of the royal blood, upon out-door excursions, and who has the care and management of their horses.

Eques Auratus. A heraldic term for a knight.

Equestrian. A man who rides on horseback; a horseman; a rider.

Equestrian Order. Among the Romans, signified their knights or equites; as, also, their troopers or horsemen in the field.

Equip, To. To furnish an individual, a corps, or an army with everything that is requisite for military service, such as arms, accoutrements, uniforms, etc.

Equipage. In military matters, is the name given to the necessaries of the soldier. The equipment of a private is often used as a name for the whole of his clothes, arms, and accoutrements, collectively. The equipage of the camp is of two kinds, camp and field equipage.

Equipments, Cannoneers’. Include the hausse pouch, cartridge pouches, primer pouches, and thumb-stall, used in the field service. The equipments for a field-piece are the tampion and strap, vent cover and tarpaulin. Other things used in service of cannon are called implements, which see.

Equipments, Horse. In the mounted service, comprise the bridle, halter, watering bridle, saddle, saddle-bags, saddle blanket, nose-bag, lariat, curry-comb, brush, etc.

Equipments, Infantry. Comprise the personal outfit of the soldier, excluding arms proper and clothing. A set of equipments is called a kit (which see). The standard equipments for infantry include the knapsack, belts, and plates, cartridge-box, bayonet-scabbard, haversack, and canteen. The knapsack, haversack, and canteen are only used in marching. In the United States there is a strong tendency towards discarding the knapsack; a roll made of the blanket, piece of shelter-tent, or overcoat, being frequently used instead. A clothing-bag is also sometimes used to take its place. The best manner of arranging and slinging the various articles carried, for the comfort and health of the soldier, is still an open question. In future wars it is probable that an intrenching tool will be added to the soldier’s equipment. The equipments for a cavalry soldier in the United States are very much the same as for infantry.

Equipments, Signal. The flags, staffs, flying torches, fort torches, flame shades, haversacks, telescopes, etc., used in signaling. A set of equipments for one man is called a signal kit.

Equites. An order of equestrian knights introduced among the Romans by Romulus.

Eretria. One of the most celebrated of ancient cities, and, next to Chalcis, one of the most powerful in Euboea. After the Peloponnesian war, the city was governed by tyrants.

Erfurt. A town of Prussian Saxony, on the river Gera; it was founded in 476. Erfurt was ceded to Prussia in 1802. It capitulated to Murat, when 14,000 troops surrendered, October 16, 1806. In this city Napoleon and Alexander met, and offered peace to England, September 27, 1808. The French retreated from Leipsic to Erfurt, October 18, 1813. This place was restored to Prussia by the Congress of Vienna.

Ericius. In Roman antiquity, a military engine, so named from its resemblance to a hedge-hog. It was a kind of chevaux-de-frise, placed as a defense at the gate of the camp.

Erie, Fort. A strong fortification in Upper Canada, on the northern shore of Lake Erie. Here the British were defeated by the Americans, August 15, 1814.

Erlau. A fortified town of Hungary, the old castle of which was frequently besieged during the Turkish wars, both by Moslem and Christian.

Eryx. A city and mountain in the west of Sicily, 6 miles from Drepana, and a short distance from the sea-shore. The possession of the town of Eryx was contested by the Syracusans and Carthaginians. A great battle was fought off the town between the fleets of the two nations, in which the Syracusans were victorious. The town subsequently changed hands more than once, but it seems to have owned the Carthaginian supremacy at the time of the expedition of Pyrrhus, 278 B.C. Though taken by that monarch, it once more fell into the hands of its original conquerors, who retained it till the close of the first Punic war.

Erzroom, Erzroum, or Erzrum. A fortified town of Armenia (Asiatic Turkey), on the river Kara-Soo, a branch of the Euphrates. Its position renders it an important military post. In 1210 it was taken by the Seljooks, who are said to have destroyed here 100 churches; taken by the Ottoman Turks in 1517. It was taken by the Russians in 1829, but was restored to Turkey in the following year.

Escadron (Fr.). Squadron. Froissart was the first French writer who made use of the word escadron to signify a troop of horse drawn out in order of battle. The term escadron is more ancient than the word battalion.

Escalade. From the Latin scala, a ladder. In siege operations, a mode of gaining admission within the enemy’s works. It consists in advancing over the glacis and the covert way, descending, if necessary, into the ditch by means of ladders, and ascending to the parapet of the curtain and bastions, and are either procured on the spot, or are sent out with the siege army. The leaders constitute a forlorn hope.

Escale (Fr.). A machine used to ply the petard.

Escape of Gas. See Gas-check and Breech Mechanism.

Escarp. In fortification, the surface of the ditch next the rampart, the surface next the enemy being termed the counterscarp. Called also scarp.

Escarp Galleries. Galleries constructed in the escarp for the purpose of flanking the ditch caponniÈre.

Escarpment. Ground cut away nearly vertically about a position, in order to render it inaccessible to the enemy.

Escort. A body of troops attending an individual as a guard. The term is also applied to a guard placed over prisoners on a march, to prevent their escape, and to the guard of a convoy of stores.

Escort, Funeral. See Funeral Escort.

Escort of Honor. A body of troops attending a personage of rank by way of military compliment.

Escort of the Color. The military ceremony of sending for and receiving the colors of a battalion.

Escouade (Fr.). In the old French service generally meant the third part of a company of foot or a detachment. Companies were divided in this manner for the purpose of more conveniently keeping the tour of duty among the men. We have corrupted the term, and called it squad.

Escuage. An ancient feudal tenure by which the tenant was bound to follow his lord to war or to defend his castle.

Espadon. In old military works, a kind of two-handed sword, having two edges, of a great length and breadth; formerly used by the Spanish.

Espauliere (Fr.). A defense for the shoulder, composed of flexible, overlapping plates of metal, used in the 15th century; the origin of the modern epaulette.

Espiere. A town of Belgium, 8 miles from Courtrai, where the allied Austrian and English army defeated the French, May 22, 1794.

Espingard, or Epingare (Fr.). An ancient name for a small gun under a 1-pounder. They were used as early as the 14th century.

Espingole, or Spingole (Fr.). A blunderbuss; a kind of blunderbuss which, in early times, was loaded with several balls; the charges were separated from each other by tampions in which a hole was made, and thus the balls were fired in succession.

Espinosa de la Monteros. A town of Spain, on the Trueba, 50 miles from Burgos. The French defeated the Spaniards here in 1808.

Esplanade. In fortification, is the open space intentionally left between the houses of a city and the glacis of its citadel, so that the enemy may not be able to erect breaching batteries under cover of the houses. In old works on fortification, the term is often applied to the glacis of the counterscarp, or the slope of the parapet of the covered way towards the country.

Espontoon (Fr.). A sort of half pike, about 3 feet in length, used in the 17th century. The colonels of corps as well as the captains of companies always used them in action. This weapon was also used by officers in the British army.

Espringal. In the ancient art of war, a machine for throwing large darts, generally called muchettÆ.

Esprit de Corps (Fr.). This term is generally used among all military men in Europe. It may not improperly be defined a laudable spirit of ambition which produces a peculiar attachment to any particular corps, company, or service. Officers without descending to mean and pitiful sensations of selfish envy, under the influence of a true esprit de corps rise into an emulous thirst after military glory. The good are excited to peculiar feats of valor by the sentiments it engenders, and the bad are deterred from ever hazarding a disgraceful action by a secret consciousness of the duties it prescribes.

Esquimaux. The tribes inhabiting Greenland and Arctic America. Those inhabiting the continent are found in sparse settlements from Behring Strait to Labrador. They are generally peaceable. Some of these in Greenland have been civilized by the influence of the Danes.

Esquire. In chivalry, was the shield-bearer or armor-bearer to the knight. He was a candidate for the honor of knighthood, and thus stood to the knight in the relation of a novice or apprentice. When fully equipped each knight was attended by two esquires.

Essedarii. In Roman antiquity, gladiators who fought in a heavy kind of chariot called esseda or essedum. The esseda (which derived its name from the Celtic word ess, signifying a carriage) was a ponderous kind of chariot much used in war by the Gauls, the BelgÆ, and the Britons. It differed from the currus in being open before instead of behind; and in this way the owner was enabled to run along the pole, from the extremity of which, or even from the top of the yoke, he discharged his missiles with surprising dexterity.

Essek, or Eszek. A town and fortress of the Austrian empire, in Sclavonia, on the Drave. It contains an arsenal, barracks, and other military buildings. There were several battles fought here between the Turks and Germans. It was finally taken from the Turks in 1687, since which time it has continued in the hands of the house of Austria.

Essling. A village of Lower Austria, on the left bank of the Danube, 6 miles east of Vienna. Between this village and that of Aspern the French were repulsed by the Austrians in a severe engagement in 1809. See Aspern.

Establish. A technical phrase to express the quartering of any considerable body of troops in a country. Thus it is common to say, the army took up a position in the neighborhood of ——, and established the headquarters at ——.

Establishment. The quota of officers and men in an army, regiment, troop, or company.

Establishment, Peace. Is the reduced condition of an army suited to a time of peace.

Establishment, War. Is the augmentation of regiments to a certain number, by which the whole army of a country is considerably increased, to meet war exigencies.

Estacade (Fr.). A dike constructed of piles in the sea, a river, or a morass, to check the approach of an enemy.

Estafette (Fr.). A military courier, sent express from one part of an army to another.

Esthonia, or Revel. A Russian province, said to have been conquered by the Teutonic knights in the 12th century; after various changes it was ceded to Sweden by the treaty of Oliva in 1660, and finally to Russia by the peace of Nystadt in 1721, having been conquered by Peter in 1710.

Estimates. Army estimates are the computation of expenses to be incurred in the support of an army for a given time.

Estimating Distances. See Pointing.

Estoc (Ital.). A small dagger worn at the girdle, called in Elizabethan times a tucke.

Estoile. See Etoiles.

Estradiots, or Stradiots. Grecian and Albanian horsemen, some of whom were employed in the Italian wars by Charles VIII.; their favorite weapon was the zagaye; besides this they had a broadsword, and club slung on the bow of the saddle, with sleeves and gauntlets of mail.

Estramacon (Fr.). A sort of two-edged sword formerly used. A blow with the edge of a sword.

Etat Major (Fr.). The staff of an army, including all officers above the rank of colonel; also, all adjutants, inspectors, quartermasters, commissaries, engineers, ordnance officers, paymasters, physicians, signal-officers, judge-advocates; also, the non-commissioned assistants of the above officers.

Etoiles (Fr.). Small redoubts which are constructed by means of angles rentrant and angles sortant, and have from 5 to 8 salient points. This species of fortification has fallen into disuse, and are superseded by square redoubts, which are sooner built and are applicable to the same purpose of defense.

Etoupille (Fr.). An inflammable match, composed of three threads of very fine cotton, which is well steeped in brandy mixed with the best priming gunpowder.

Etruria, or Tuscia (hence the modern name Tuscany). A province of Italy, whence the Romans, in a great measure, derived their laws, customs, and superstitions. The subjugation of this country forms an important part of early Roman history. A truce between the Romans and Etrurians for forty years was concluded in 351 B.C. The latter and their allies were defeated at the Vadimonian Lake, 310 B.C.; with the Boii their allies, 823 B.C., and totally lost their independence about 265 B.C.

Euboea. The largest island in the Ægean Sea. Two of its cities, Chalcis and Eretria, were very important, till the former was subdued by Athens, 506 B.C., and the latter by the Persians, 490. After the Persian war Euboea became wholly subject to Athens. It revolted in 445, but was soon subdued by Pericles. After the battle of ChÆronea, 338, it became subject to Macedon. It was made independent by the Romans in 194, but was afterwards incorporated in the province of Achaia. It now forms part of the kingdom of Greece.

Eupatoria, or Koslov. A town of Russia, on the west coast of the Crimea. In September, 1854, the allied English and French armies landed near here, and the town soon after was occupied by a small detachment. The Turks subsequently occupied it, and in 1855 it was attacked by the Russians, who, however, were repulsed by the Turks, and the Anglo-French ships of war, lying in the neighboring roadstead.

Eureka Projectile. See Projectile.

Europe. The least extensive, but most civilized of the five great divisions of the globe. It is bounded by the sea in all directions, except the east, where it is separated from Asia by a boundary-line, formed by the river Kara, the Ural Mountains and River, and the Caspian Sea. For military and naval events which occurred in Europe, see separate articles.

Eurymedon (now Kapri-Su). A small river in Pamphylia, celebrated for the victory which Cimon gained over the Persians on its banks, 469 B.C.

Eustace, St. In Lower Canada; the rebels were defeated here, December 14, 1837, and compelled to surrender their arms. Their chiefs fled.

Eustatius, St. A West India island, which was settled by the Dutch in 1632; taken by the French in 1689; by the English in 1690; again by the British forces under Rodney and Vaughan, February 3, 1781. It was recovered by the French, November 26, same year. It was again captured by the British in 1801 and 1810, and restored to the Dutch in 1814.

Eutaw Springs. A small affluent of the Santee River, in South Carolina. On its banks was fought, September 8, 1781, the battle of this name. Gen. Greene, determining to dispossess the British of their remaining posts, with about 2000 men attacked their forces under Col. Stuart. The British were routed and fled; but finding in their flight some objects affording shelter, rallied and repulsed their assailants, and Gen. Greene finding it impossible to dislodge them, retreated to his camp with 500 prisoners. The British loss was about 1000; the American about 600.

Euxine Sea. See Black Sea.

Evacuate. To withdraw from a town or fortress, in consequence either of a treaty or a capitulation, or of superior orders.

Evagination. An unsheathing or drawing out of a sheath or scabbard.

Evesham. A borough and market town of England, in Worcestershire, on the Avon. Near this place a battle was fought between Prince Edward, son of Henry III., and Simon de Montfort, earl of Leicester, August 4, 1265.

Evidence. Is that which makes clear, demonstrates, or ascertains the truth of the very fact or point in issue. Hearsay evidence, the declaration of what one has heard from others. This species of evidence is not admissible in courts-martial.

Evocati. Were a class of soldiers among the Romans, who, after having served their full time in the army, entered as volunteers to accompany some favorite general. Hence they were likewise called emereti and beneficiarii.

Evocation. A religious ceremony which was observed among the Romans at the commencement of a siege, wherein they solemnly called upon the gods and goddesses of the place to forsake it and come over to them. When any place surrendered they always took it for granted that their prayer had been heard.

Evolutions. Are the movements of troops in order to change position. The object may be to maintain or sustain a post, to occupy a new post, to improve an attack, or to improve a defense. All such movements as marching, countermarching, changing front, forming line, facing, wheeling, making column or line, defiling, deploying, etc., come under the general heading of evolutions.

Evreux (anc. Mediolanum). A city of France, capital of the department of Eure. It has sustained several sieges, and was burned by Henry I. of England in 1119.

Examination, Boards of. See Boards of Examination.

Exarchs. Were appointed by the Byzantine emperors of the East, to govern Central Italy after its conquest by Belisarius and Narses, 548. They ruled from 568 to 752, when Eutychus, the last, was overcome by Astolphus the Lombard.

Exauctoratio. In the Roman military discipline, differed from the missio, which was a full discharge, and took place after soldiers had served in the army twenty years; whereas the exauctoratio was only a partial discharge; they lost their pay, indeed, but still kept under their colors or vexilla, though not under the aquila or eagle, which was the standard of the legion; whence instead of legionarii, they were called subsignani, and were retained till they had either served their full time, or had lands assigned them. The exauctoratio took place after they had served seventeen years.

Excavation. The art of cutting or otherwise making hollows in the earth; also the cavity formed.

Exchange. The act of two officers changing regiments, battalions, or batteries. The mutual giving up of an equal number of prisoners by hostile states or armies. In this sort of exchange an officer, according to his rank, is reckoned as equal to a certain number of men or of officers of a lower grade than his own.

ExcubiÆ. In ancient warfare, the watches and guards kept in the day by the Roman soldiers. They differed from the vigiliÆ, which were kept in the night.

Execution, Military. Is the pillaging or plundering of a country by the enemy’s army. Military execution also means every kind of punishment inflicted in the army by the sentence of a court-martial; which is of various kinds, including putting a soldier to death by shooting him, which is the ordinary punishment of deserters to the enemy, mutineers, etc. This form of death is considered less disgraceful than hanging by the neck.

Exempt. Not subject, not liable to. Men of certain age are exempt from serving in the militia. An aide-de-camp and brigade-major are exempt from all regimental duties while serving in those capacities. Officers on courts-martial are sometimes exempt from all other duties until the court is dissolved.

Exercise. The practice of all those motions and actions, together with the whole management of arms, which are essential to the perfection of a soldier, and the rendering him fit for service.

Exercise, Artillery. Is the method of teaching the regiments of artillery the use and practice of all the various machines of war belonging to that particular arm of the service.

Exon. In England, an officer of the Yeomen of the Royal Guard; an exempt.

Exostre (Fr.). Bridge of the Helepole or movable tower of the ancients, by which they passed upon a wall during a siege.

Expanding System of Projectiles. See Projectiles, Rifle.

Expedient. A stratagem in warfare.

Expedition. Is an enterprise taken by sea or by land against an enemy, the fortunate termination of which depends on the rapidity and unexpected nature of its movements. It is usually intrusted to a commander of acknowledged talents and experience.

Expense Magazines. Are small powder-magazines containing ammunition, etc., made up for present use. There is usually one in each bastion.

Experiments. The trials or applications of any kind of military machines in order to ascertain their practical qualities and uses.

Expiration of Service. The termination of a soldier’s contract of enlistment.

Explode. To burst with a loud report; to detonate, as gunpowder, or a shell filled with powder or the like material.

Explosion. The sudden enlargement of the volume of a body by its conversion into gas or vapor. (See Explosives.) The explosion of powder may be divided into three distinct parts, viz.: ignition, inflammation, and combustion, all of which see under their proper headings.

Explosives. Substances the elements of which under certain conditions suddenly undergo a chemical rearrangement into gases, giving rise to great pressures on surrounding bodies. Modern writers recognize two different kinds of explosions,—explosions of the 1st order, or detonations, and explosions of the 2d order, or rapid combustions. Detonating explosions are practically instantaneous. The explosion is supposed to be propagated by a vibration throughout the mass. Ordinary explosions are propagated by inflammation. Gunpowder, which may be taken as a type of explosives of the 2d order, burns at a certain rate, depending upon the density. When a charge is fired the inflammation spreads from the point of ignition to all parts of the charge,—each grain is successively enveloped and burned from surface to centre. The velocity of inflammation is the greater in proportion to the degree of confinement from the increased tension of the gases. The velocity of combustion is the rate at which the solid grains are burned. It is measured by the distance passed over by the burning surface (the line being taken perpendicular to the surface) in the unit of time. Time thus enters into the explosion of gunpowder and gives it its peculiar value as a ballistic agent.

In the detonating explosives, the case is very different. These bodies may be supposed to be made up of molecules containing so many atoms of carbon, oxygen, nitrogen, etc., so placed as to be held in a state of equilibrium by their mutual attractions and repulsions, but this equilibrium is unstable; that is to say, each atom has only a very small arc of vibration in which the molecule is stable. If by any cause an atom is forced beyond this limit the equilibrium of the whole mass is destroyed, and the elements instantly rearrange themselves under the influence of the chemical affinities which obtain under the particular conditions of the explosion. This kind of explosion is brought about in various ways,—by percussion, concussion, heat, etc.,—some bodies being susceptible to one mode of firing more than another. The theory which offers the best explanation of the various phenomena is that the molecular balance is peculiarly susceptible to overturn by certain vibrations. The vibrations given out by the explosion of the fulminates seem to have the widest range in bringing about the detonation of different substances. For this reason the fulminate of mercury is the universal detonating agent. Its own susceptibility to explosion by heat, percussion, and the electric spark especially fits it for this work. Wet gun-cotton requires in addition to the fulminate a “primer” of dry gun-cotton.

Explosives, Composition of. Ordinary explosives of which gunpowder is the type are mechanical mixtures of two essential ingredients,—one a combustible, the other an oxidizing agent. The combustible is usually carbon,—sometimes associated with hydrogen. It may be sulphur or any substance having a great affinity for oxygen. Organic substances containing carbon and hydrogen are frequently used. In the chemical reaction the carbon is oxidized to carbonic acid and the hydrogen to water with the evolution of great heat.

The oxidizing substances ordinarily used are the nitrates and chlorates. Mixtures containing nitrates are the most stable, since the nitrate is comparatively slow to give up its oxygen. The chlorate mixtures are sensitive to friction and percussion, and explode with great quickness. Many of them are unsafe to handle. A new mode of preparing chlorate mixtures has been suggested which avoids this danger. A combustible liquid is used, being absorbed in cakes or lumps of potassium or other chlorate.

Detonating explosives are chemical compounds. Among them are chloride and iodide of nitrogen. Both are dangerous, violent explosives of which no practical use has been made.

The fulminates are salts of fulminic acid. The fulminate of mercury is the one in common use. See Fulminates.

The nitro-substitution compounds form a large class, comprising the most important of the higher explosives. They are all formed by the action of nitric acid on organic substances containing oxygen, carbon, and hydrogen. This action is to replace hydrogen (H) in the organic substance by hyponitric acid (NO₂) (in the acid), equivalent for equivalent. Sulphuric acid is generally mixed with the nitric, though it plays no direct part in the reaction, being used to absorb the water formed and prevent the dilution of the nitric acid.

Nitro-glycerine, the most powerful explosive in common use, is formed by the action of the acids on glycerine. See Nitro-glycerine.

Nitro-starch and nitro-mannite are analogous substances, formed by the action of the acids on starch and sugar.

Gun-cotton is produced by the action of the acids on cotton-wool—a form of cellulose. See Gun-cotton.

There are varieties of all these compounds produced, by the substitution of different numbers of equivalents of hyponitric acid, but the names are specially given to the most highly nitrated forms.

Picric acid, the salts of which form the well-known picrates, is made by the action of the acids on carbolic acid.

To heighten the effect of the lower forms of nitro-substitution compounds they are usually mixed with an oxidizing agent, such as nitrate or chlorate, which supplies the deficient oxygen. This is exemplified in Schultz’s wood powder (which see), and Reeve’s gun felt.

The picrates are similarly treated. Ammonium picrate mixed with nitre forms Abel’s picric powder (Burgess’s powder). This has been used as a bursting charge for shells.

Mixtures of two high explosives have also been used, as in glyoxiline, invented by Prof. Abel, which is gun-cotton saturated with nitro-glycerine.

Explosive effect depends upon three elements,—1st, the volume of the gases produced taken at a standard temperature; 2d, the heat evolved in the chemical reaction; 3d, the time consumed in the development of the gases. Explosive effect is directly proportional to the first two of these elements, and inversely proportional to the third. According to Bertholet, nitro-glycerine gives out twice as much heat and three and a half times as much gas as an equal weight of gunpowder, but this gives no idea of their relative explosive effects, as the element of time in the detonating explosives is so short that it cannot be calculated. So nearly is this element absent that we may consider these explosions as almost perfect Impulsive Forces. To secure ballistic effect requires the gradual application of force. When motion is imparted to a body the inertia developed is inversely proportional to the time consumed in imparting it. This resistance to motion becomes enormously great when the detonating explosives are used. For this reason their ballistic effect is small. The force which should give the projectile motion is expended in producing molecular changes in both projectile and gun. The same quality, however, fits them especially for blasting and torpedoes, where shattering effect is desirable.

Express Rifle. A modern sporting rifle of great killing power, used in hunting large or dangerous animals. They were first introduced in England, and have become celebrated in the hands of African travelers and explorers. The principle consists in using large charges of powder and a light bullet, which gives a very high initial velocity and a trajectory practically a right line for 150 or 200 yards, hence the term “Express.” To increase the killing power of the bullet it is made of pure lead and has a hollow point. Upon striking game the bullet spreads outwardly, giving a fearful death-wound. Moreover, for specially ugly game a small explosive cartridge can be dropped into the cavity in the point, making it an explosive bullet. (See Bullets, Express.) In England a caliber as large as .57 is used for some Express rifles. In the United States a caliber of .45 or .50 is considered sufficient.

Expugn. To conquer; to take by assault.

Expugnable. Capable of being expugned, forced or conquered.

Expugnation. The act of taking by assault; conquest.

Expugner. One who expugns or conquers.

Extend. A term peculiarly applicable to light infantry movements, when the files are frequently loosened, and the front of the line extended for the purpose of skirmishing. When the divisions of a column are made to occupy a greater space of ground, they are said to extend their front.

Exterior Crest. The crest of the exterior slope of a parapet.

Exterior Form of Cannon. See Ordnance, Exterior Form.

Exterior Side. In fortification, is the side of the polygon, upon which a front of fortification is formed.

Exterior Slope. In fortification, is the slope given to the outside of a parapet. It is found by experience that earth of common quality will naturally acquire a slope of 45°, even when battered by cannon. This inclination is therefore given to the slope.

External Injuries to Cannon. See Injuries to Cannon.

Extortion. Under the modern laws of war, honorable men no longer permit the use of any violence against prisoners in order to extort information or to punish them for having given false information.

Extrados (Fr.). The exterior surface of a regular arch, used in the construction of powder-magazines.

Extraordinaries of the Army. In the English service, the allowances to troops beyond the gross pay in the pay office, come under this head. Such are the expenses for barracks, marches, encampments, staff, etc.

Extraordinarii. In the ancient Roman army, a select body of men consisting of the third part of the foreign cavalry and a fifth of the infantry. These were carefully separated from the other forces borrowed from the confederate states, in order to prevent any treacherous coalition between them. From among the extraordinarii a more choice body of men were drawn, under the name of ablecti. See Ablecti.

Eylau, or Eilau. Usually called Prussian Eylau, a town in the government of KÖnigsberg, celebrated for the battle fought here between Napoleon and the allies—Russians and Prussians—under Bennigsen, February 8, 1807. The French force amounted to about 80,000, and the allies numbered 58,000, but were superior in artillery. The French claimed the victory, chiefly because the allied forces, unable to recruit their strength, were ordered to retreat from the field on the night of the battle, and to retire upon KÖnigsberg. The loss of the allies is estimated at about 20,000, while that of the French must have been considerably greater.