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for convenient firing, be four feet three inches | below a; its width three feet, if for a single line of soldiers; four feet six inches for a double rank; its slope should be one in twelve, that water may run freely off. The base, be, of the slope, up which the men mount to the banquette, should be twice its height be, and cut into steps with inclined sides, to allow of easy ascent; and where the height is considerable, a supplemental banquette (on which relieving-men can, if necessary, reload), is desirable. The interior slope, ac, of the parapet should be one in four; the exterior slope, or plongée, ad, intended for the direction of the guns on an assailant, one in six, a deviation being permitted between one in nine and one in four; but the crest being more liable to destruction as the slope of ab is augmented, it is best to keep it as small as circumstances will allow; one in six is the ordinary slope in English fortification, the angle of the interior slope being constant. In some continental services, however, the angle, cad, is kept constant at 100°, by increasing the deviation of the interior slope of the parapet from the perpendicular as the plunge of the exterior is greater. The flatter, however, the crest of the parapet is the better, as sand-bags are in certain cases ranged on it to form cover for the men, while they fire through loopholes left in this additional defence. Earth of medium tenacity maintains its position properly when sloped at an angle of 45°; and this is the greatest angle which can be counted on for the outer slope of the parapet. The scarp, l, and counterscarp, in, of the ditch need not have so great an incline, as the ground in which they are cut has usually had time, and the footsteps of ages, to consolidate it. In such cases, the base of the triangle is frequently made equal to half the perpendicular. Cases, of course, occur in which steeper banks are considered indispensable; and then, to prevent slips, the earth must have a coating to keep it up, which may be of fascines, hurdles, planks, or sand-bags, for temporary works, or those constructed in the midst of action; while the most solid masonry performs the same function in fortresses of a more permanent nature. This outer coating is denominated a revêtement.

In fig. 7, ghi, is the glacis, formed during the excavation of the ditch, and having for object the bringing of an advancing enemy into the best line of fire from the parapet. The base and perpendicular of its interior slope, gh, should be equal; the slope of the outer face should be one in twelve, unless the slope of the ground render some different angle desirable. An advanced glacis, k in fig. 7, is sometimes adopted, in order that the enemy may the sooner be brought under fire. It is absolutely necessary that the crest of the parapet should be five and a half feet higher than the crest of the

glacis, as, otherwise, an assailant having reached the latter, would be able to pour a musketry-fire over the former into the work. No part of any glacis, whether near or. advanced, should be more than two feet below the line of fire from the parapeti. e., the line joining the crests of the parapet and glacis continued; if more depth be allowed, the enemy may advance in a crouching posture, without being liable to be hit. Advanced glacis are usually made of earth thrown up in prolonging beneath the ground the plane of the preceding glacis. They may be defended entirely from the parapet, in which case palisades or abattis are often fixed (as in fig. 7) to delay the advancing enemy when at the point of greatest exposure. On the other hand, these advanced glacis are occasionally defended as a series of advanced intrenchments, and only abandoned, one by one, as the defenders are driven in towards their main work.

The dimensions of the ditch depend in some measure on the amount of earth required for the parapet and glacis; but in addition to being the mine whence the materials for the latter works are drawn, the ditch must also oppose a considerable obstacle to any hostile advance. To do this effectually, the minimum width across the top is 18 feet; its depth need only be limited by the trouble of raising the earth; but in practice 12 feet is found the greatest which can be conveniently arrived at. Having ascertained the profile of the parapet, with its banquette or banquettes, bonnets, traverses, glacis, &c., it becomes a mere matter of mensuration to compute the area of a section, to multiply it by the length, and so to obtain the cubic feet of earth required. With the length of the ditch known, a very simple calculation then exhibits its width and depth-a small allowance being made for the fact that the earth, dug out from the ditch, where it has probably been long compressed, will occupy somewhat more space when thrown up, and broken into clods, for forming the parapet.

The scarp, or inner face of the ditch, is most difficult of ascent by the assailant, when in a continuous line with the parapet (as in fig. 7); but sometimes it would be dangerous to construct the work with this continuity, as damage to the scarp would jeopardise the stability of the parapet. In these cases a narrow step, called a Berm (q. v.) of from two to four feet, is made to intervene between the foot of the parapet and top of the scarp: as a precaution, it is covered with all possible obstacles to any lodgment being effected on it by the enemy. When a berm is employed, greater ste puess is usually given to the scarp.

The counterscarp, or outer sloping side of the ditch, should be somewhat steeper than the scarp

FORTIFICATION.

The bottom of the ditch should slope from both sides towards the centre, to carry off the water; and obstacles should be scattered about to prevent an enemy from forming his troops in the ditch.

EARTHWORKS IN FIELD FORTIFICATION.-As the most readily constructed, earthworks naturally recommend themselves to the engineer, who, in the field, is called upon to defend the position of an army against sudden attack. Their utility has been shewn in their employment from the earliest times; and modern experience tends to prove that earth-parapets are of all fortifications among the most difficult to overcome. An army manoeuvring before a superior force, can scarcely hope to avoid battle being thrust upon it, unless, strengthened by fieldworks, it be rendered more nearly equal to the adversary. Napoleon, Marlborough, Eugène, Wellington, have given their names as witnesses to the indispensability of such works. The Russian parapets at Borodino made the French victory so sanguinary a triumph that it was useless to the victors. A few redoubts at Pultowa saved Peter the Great from total defeat by his formidable Swedish rival. The world-famed lines of Torres Vedras enabled Wellington with 50,000 troops, half of whom were untried Portuguese, to withstand for five months, and ultimately to drive back, the hitherto victorious army of 70,000 French, under such commanders as Masséna, Ney, and Junôt. The earthworks surrounding Sevastopol partook greatly of the nature of fieldworks for the protection of a large army, and history will not forget to recount the resistance they offered for almost a year to the best troops of the civilised world.

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For a line, whether of earth or masonry, to be efficient, it must combine artillery fire with that of musketry. The guns will generally be so placed as to command some specific line of approach, such as a ravine, a line of abattis, or some portion of the glacis. They should themselves be as little exposed as possible, nor should the gunners be uncovered more than is absolutely requisite. To effect this, gun is generally made to fire through an embrasure (q. v.) in the parapet, instead of over the latter. The embrasure is a cutting through the solid parapet, 20 inches wide at its inner extremity, and outwards half as much as the width of the parapet. In cases where it is necessary, for proper command, that the line of fire should not be lower than the top of the parapet, the embrasure is made through an additional parapet-raised, as in the previous case of the bonnet, above the original one. bottom of the embrasure is called the sole, and slopes downward sufficiently to allow of a certain depression being given to the gun. The remainder of a parapet below the sole is the genouillerè (from genou, a knee), and in field fortification should be three and a half feet high; the portion between two embrasures is the merlin (Ital. merlone, battlement); and an embrasure need not cut the parapet perpendicularly, an angle being admissible, when an oblique fire is necessary. When, however, the obliquity would exceed 70°, it is usual, in order that the thickness of the parapet should not be too much diminished, to form a projecting angle in it, through which the embrasure is cut (as in fig. 8). The sides of the embrasures are cheeks, and require revêting.

Fig. 8.

A barbette is a platform raised behind a parapet,

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higher than the general interior, with a view to guns being fired from it over the parapet.

There are certain fixed rules in all fortification, such as:-1. The length of lines must never exceed musketry range, or the flanking works would become ineffective for their object. 2. The angles of defence should be about right angles. 3. Salient angles should be as obtuse as possible. 4. Ditches should have the best possible flanking. 5. The relief of the flanking-works must be determined by the length of the lines of defence. 6. The value of almost every detached work depends on the support it can give to or receive from an army or other work or works. 7. The reduction of every fortified work is merely a question of time; and a work fairly surrounded is sure to fall, unless relieved from without.

Fig. 9.-Redan.

Fieldworks, which, it must be borne in mind, are intended merely to support or strengthen an army, may either have a complete circuit of parapets, or may be open at the gorge in the rear. The latter are, of course, the simplest; but they are only available in positions which the enemy cannot turn, or where protected by the sweeping fire of other works behind. Of this class the Redan, a mere salient angle (see fig. 9), is the simplest and the representative form. Of the closed forts, there are Redoubts, usually square; Star-forts, now considered objectionable; bastioned forts, as in fig. 10, which flank their own ditches almost perfectly, while scarcely susceptible of being flanked themselves. To understand the nature of a single bastion, see A (fig. 10), which represents one at the corner of a square work; ab is the left flank, bc the left face, cd the right face, de the right flank; ae is the gorge; af, fe are the demi-gorges, being continuations of the sides, or curtains, of the work; a and e are the left and right curtain angles; b and d, the left and right shoulder angles, and c is the flanked angle.

Fig. 10-Bastioned Fort.

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Continued lines are simple parapets, either connecting fortified posts, or covering the front or flank of an army. Redans joined by curtains (as in fig. 11) are those most easily constructed; but Fig. 11.-Continued line of as the ditches can only be defended by an oblique

Redans.

fire, the curtains are occasionally so broken as to form nearly right angles with the faces of the redan, as in the dotted line; they then become lines of tenailles.

Lines en Crémaillière have long faces with perpendicular flanks. Lines with intervals are often

Fig. 12.-Line with intervals.

as effective as continued lines. They consist of detached works, in two lines, within musketry

FORTIFICATION.

fire of each other. The re-entering angle, abc (fig. 12), should as nearly as practicable be a right angle. The celebrated lines of Torres Vedras, before adverted to, consisted of 150 detached forts.

Tête-du-pont, is a work constructed to cover the approaches to a bridge, and will be found described under BRIDGE-HEAD.

A tenaille is the reverse of a redan, and consists of two faces forming a re-entering angle: it can only be used in connection with some other work.

A flèche is a breastwork of two faces, forming a salient angle, constructed on the exterior of a glacis, usually at its foot, in order to defend the ground before a bastion or ravelin.

Having now explained the principal forms which elemental works of fortification are made to assume, we proceed to describe-very briefly, of coursethe systems into which these have been incorporated for the defence of fortresses, towns, and other permanent purposes. It will merely be necessary to state, in addition to what has been already written, that a rampart is a raised structure of earth or stone, above the mean level of the country, on which the parapets, &c., can be thrown up, and which affords to the town or space protected the extra cover of its height, while it elevates the inner works sufficiently to enable them to command and fire over those situated exteriorly to themselves. It need scarcely be said that a line which can be made of earth may equally be constructed of any other material which circumstances may render desirable, the maximum resistance and minimum liability to splinter being the qualities to be chiefly considered.

SYSTEMATIC FORTIFICATION FOR PERMANENT WORKS.-Adverting to the most ancient fortifications mentioned in history, we find Greek cities surrounded with walls of brick and rubble, and occasionally of stone in huge blocks. Babylon had a wall of prodigious circuit-100 feet high, 32 feet thick, and surmounted by towers. Jerusalem, at the time of Vespasian's siege, had similar walls with masonry of enormous solidity. These seem to repreBent fortification as it stood from the time of that

emperor to the introduction of cannon for breaching purposes. Then the square and round towers, which had formed sufficient flanking defence against arrows, proved useless when cannon-balls, fired from a distance, were the instruments of assault. At the same time, the walls, which had resisted batteringrams, crumbled to atoms under the strokes of artillery.

Fortunately, however, the art of defence has always made equal progress with that of attack; and, early in the 15th, if not late in the 14th c., the Italians had commenced to flank their walla with small bastions. The bastions at Verona, built by Micheli in 1523, are usually looked upon as the oldest extant specimen of modern fortification. Tartaglia and Albert Dürer, painter and engineer, were early in the field. In most of the earlier systems the face of the bastion was perpendicular to its flank. The first principles were successively improved by Marchi, an Italian, who died 1599, by Errard Boisle-Duc, and De Ville, under Henry IV. and Louis XIII. of France. The Count de Pagan, whose treatise appeared in 1645, did much towards demolishing previous errors, and laid the basement of that science which Vauban subsequently wrought almost to perfection. Born in 1633, Vauban had a genius which penetrated in every direction, equally in the ways of war and in those of peace. He might pos sibly have taught how fortresses could be rendered impregnable, had not the restless ambition of his master, Louis XIV., led him to demonstrate, first, that the reduction of any work was a mere question of time and powder. His talent so improved the system of attack, that even he himself could not construct a rampart that should withstand the fire conjured up against it by his discoveries. He constructed 33 new fortresses, improved above 100, and conducted personally more than 50 sieges. То him are soldiers indebted for the sweeping fire of ricochet, and to him in a degree for the traverses which endeavour to render it harmless. Coehoorn, director-general of the fortresses of the United Provinces, was the contemporary, rival, and opponent of Vauban; his master-piece is Bergen-op-Zoom.

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A, bastion; B, curtain; C, tenaille; D, caponnière; E, ditch; F, ravelin; G, covert-way; H, salient place of arms; I, re-entering place of arms; K, glacis.

Cormontaigne, Belidor, Montalembert, Bousmard, and Carnot may also be mentioned as conspicuous masters in the science.

Irrespective of irregularities in the form of the place to be defended, a particular polygon is selected as that on which the lines of defence are to be

drawn. Each side of this is a face of defence, and the length of a side is rarely made greater than 360 yards.

Vauban's first system is shewn in fig. 13 as regards the outline of its ground-plan; fig. 14 displaying the same in profile.

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bastion, the line of advance is only covered by an extremely oblique fire. To obviate this, a ravelin, F, is constructed on the further side of the main ditch, which commands the doustful fronts, and, at

the same time, forms an outwork capable of assisting in the general scheme of defence. To trace the main ditch, describe from the flanked angle of the bastion, a or b, an arc with radius 30 yards (if dry

FORTIGUERRA-FORTUNATUS.

ditch, 36 if wet), and from these arcs draw tangents to the shoulders, d and g, of the opposite bastions. These tangents, meeting in the line cC, form the counterscarp line of the main ditch. From h, the re-entering angle of the counterscarp, set off 100 yards along the perpendicular to i, which will be the apex of the flanked angle of the ravelin. From i, draw lines to points situated in the faces of the bastions, 10 yards from the shoulder angles; these lines to the points intersecting the counterscarp give the faces of the ravelin. The ditch of the ravelin is 20 yards wide, with counterscarp parallel to the escarp. The zigzag line now arrived at gives the inner side of the covert-way-10 yards wide -behind the glacis, which last slopes gradually towards the country, and is ordinarily the outer work of all. The tenaille is a comparatively low parapet sweeping the depressed interior of the ravelin, and commanded by the bastions and curtain.

The caponier, forming a communication between the tenaille and the ravelin, consists of a passage between two low parapets, each with a glacis sloping towards the ditch, which is swept from the

work.

Nine feet clear are allowed round the traverses on the covert-way; at the re-entering angles of the covert-way, places of arms are formed by setting off 30 yards on each side, and with this as gorge, advancing faces inclined to each other at 100°. If the polygon had been a square, cC would have been ab; if a pentagon, ab; and for any polygon of

more sides than seven, ab.

Vauban's second and third systems were those in which he adapted old walls to his modern improvements. Availing himself of the works already formed, he added counterguards in front of the corner-towers, thereby making hollow bastions, and avoiding the necessity of entirely rebuilding.

Coehoorn's system had counterguards in front of the bastions and parallel to them. The flanked angle of his ravelin had a fixed value-viz., 70°. Cormontaigne widened the gorge of his ravelin, thereby reducing the length of the bastion face available for breaching from without. He also revived the step-like formation of the covered way, originally seen in Speckle in the 16th c., and which gives defenders a continued line of fire from each traverse along the covert-way.

The modern system differs but little from that of Cormontaigne. The re-entering places of arms have circular fronts instead of angular; the angle of the ravelin is fixed at 60, and all the best points of older styles are associated.

Fig. 15 is intended to present at one view a representation of the systems in force since artillery came into common use, as well as the gradual transition from square towers on castle walls to flanked bastions on modern lines. The elements of fortifying against shipping will be found under MARINE FORTIFICATION; the principles of attacking fortresses generally, under SIEGE, and MINES, MILITARY.

FORTIGUERRA, NICOLO, an Italian poet, was born at Pistoja, November 7, 1674. Destined from youth for the church, he proceeded to Rome at an early period, where the power of the prelate Carlo A. Fabroni, who was his relative, speedily secured him advancement, and where he was ultimately raised to the dignity of prelate and papal chamberlain by Clement XI. An ardent cultivator and protector of letters, it must be owned that F.'s own compositions are more prized for a certain rich joviality of imagery, and profuse facility of language, than for any salient beauty of style or conception, His chief work, Il Ricciardetto, was originally commenced in confutation of friends, who maintained

that the striking ease and fluency of Ariosto, Berni, and other poets of a similar school, were but apparent, and in reality the fruit of deep art and severe labour. F., in a few hours threw off an entire canto of Il Ricciardetto, strikingly in imitation of the above poets, and continued the work at random much beyond its originally designed limits. It was published in 1738, two years after his death, and met with unequivocal favour, notwithstanding the incredible incidents and licentious images with which it is replete. F. died 7th February 1735.

FORTRO'SE, or FORTROSS, a parliamentary and royal burgh, seaport, and watering-place in the east of Ross-shire, on the west side of the Moray Firth, opposite Fort George, ten miles north-northeast of Inverness. Pop. (1861) 928. It unites with Inverness, Forres, and Nairn in sending a member to parliament. F. had a fine cathedral and a bishop's palace; but both of these buildings were partially destroyed under Cromwell, and the stones sent to Inverness, to be used in building a fort there. It has a good trade in various kinds of produce, as pork, eggs, all sorts of grain, and potatoes. 16th c., F. had a considerable trade, and is said to have been the seat of arts, science, and divinity in the north of Scotland. Chanonry, with which it was united in 1444, was formerly the see of the bishops of Ross.

In the

FO'RTS AND FORTALICES. The military power of the state is intrusted by the constitution of this country to the sovereign. After having been in the time of Charles I., it was again vindicated for unconstitutionally claimed by the Long Parliament the crown by 2 Car. II. c. 6. This branch of the royal prerogative extends not only to the raising of armies and the construction of fleets, but to the building of forts and other places of strength. Sir Edward Coke lays it down (I Inst. 5), that no subject the licence of the king; and it was enacted by 11 can build a house of strength embattled without Henry VII. c. 18, that no such place of strength could be conveyed without a special grant.

FORTU'NA, called by the Greeks, Tyche, was in classical mythology the Goddess of Chance. According to Hesiod, she was a daughter of Oceanus; according to Pindar, a sister of the Parcæ. She differed from Destiny or Fate, in so far that she worked without law, giving or taking away at her own good pleasure, and dispensing joy or sorrow indifferently. She had temples at Smyrna, Corinth, and Elis. In Italy, she was extensively worshipped from a very early period; and had many names, such as Patricia, Plebeia, Equestris, Virilis, Primigenia, Publica, Privata, Muliebris, Virginensis, &c., indicating the extent and also the minuteness of her superintendence. Particular honours were paid to her at Antium and Præneste; in the temple of the former city, two statues of her were even consulted as oracles. Greek poets and sculptors generally represented her with a rudder, as a symbol of her guiding power; or with a ball, or wheel, or wings, as a symbol of her mutability. The Romans proudly affirmed that when she entered their city, she threw away her globe, and put off her wings and shoes, to indicate that she meant to dwell with them for ever.

It

FORTUNATE ISLANDS. See CANARIES. FORTUNATUS is the title of one of the best people's books (Volksbücher) ever written. originated about the middle of the 15th c., though many of the tales and legends included in it are of much older date. The opinion that it was worked up into German from a Spanish or English original may be considered as set aside. The substance of the book is that F., and his sons after him, are the

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