number (1825) was 1,991,405,278. Ireland being exempt | The curved line at the bottom given by the camber-slip is from the duty on bricks, is not included in these returns. cut by means of the bevel; every angle of each brick The whole duty is drawn back on exportation. being different, they are copied by the bevel, and set off BRICKLAYER. A charter was granted in 1568 to the in succession on the mould and numbered, so that for the tilers and bricklayers in London, by which they were formed rest of the operation, the workman has only recourse to the into a corporate body, consisting of a master, two wardens, mould. twenty assistants, and seventy-eight livery. Bricklayers form a very numerous body of artizans in this country. A good workman can lay 1500 bricks daily in walls. His wages in London are 5s., 5s. 6d., and even 68. a day. Country workmen have generally 4s. a day. Wages however vary according to the locality. BRICKWORK. Brick walls are of various thicknesses. Four and a half inches or half brick; nine inches or one brick; fourteen inches or one and half brick; and eighteen inches or two bricks; and two bricks and a half and so on, to about three feet two inches. Except in large public works, walls are seldom built more than four bricks thick. In good work three bricks are well bonded together. There are four kinds of bond in use in laying bricks, called English bond, Flemish bond, herring bond, and garden wall bond. English bond consists of bricks laid lengthwise on the length of the wall, and crossed by bricks laid with their breadth on the wall. The former are called stretching courses, and the bricks stretchers; the latter heading courses, and the bricks are called headers. This bond is much used in water-works. Flemish bond consists in laying a header and stretcher alternately in the same course. This bond, which is considered by bricklayers the most beautiful, is not so effectual as the English bond. To unite more firmly the Flemish bond brickwork, especially in thick walls, and to remedy the weakness of the stretching courses, the bricks are often placed at an angle of forty-five degrees parallel to each other, and reversed in the alternate courses; this is done in the centre or core of thick walls, and is called herring-bone. It is advisable only to use this diagonal brickwork occasionally, because, though the bricks in the core have sufficient bond, the sides, on account of the triangular interstices, are very improperly tied to the core. Flemish bond is however varied according to the width of the openings in the wall or front of a house. The reveals of windows are bonded every alternate course, with a closure or quarter brick and a half brick. The reveals of doors are terminated with a half brick and closure. Garden-wall bond consists of three stretchers and one header in nine inch walls, but when fourteen inches thick, the Flemish bond is used. In English bond, it is to be observed, that as the length of a brick is nine inches, and its breadth four and a half, it is the practice to prevent two perpendicular joints from falling over each other, at the end of the first stretcher from the corner header, by the introduction of a closure, or by a three-quarter brick or bat as it is technically called, instead of a stretcher at the corner. The most difficult work for the bricklayer to execute is the groining or intersection of arches in vaults, where every brick has to be cut to a different bed. This and the arches called gauged arches, either circular or straight, cut with the axe and rubbed on the banker or table, and afterwards set in lime only, called putty, require the neatest workmanship. Some straight arches are made roughly; that is, the bricks are inclined each way, parallel to each other on the respective skewbacks or shoulders of the arch, until the soffitends of the bricks touch, when the vacant space at top is filled with two bricks forming a wedge: this arch, like other straight arches, is constructed on a camber slip, or piece of wood slightly curved on the upper side, and serving as a centering. The bricks for rubbed or gauged arches are cut with radiating lines. Those for cambered or straight arches are cut by the manual skill of the workman, and the lines do not radiate exactly to one centre, like the bricks in semicircular gauged arches. The following is the method adopted by bricklayers in cutting the straight arch. The straight arch, so common in houses in London, is first drawn out the full size on a board; the top part is a straight line; the lower, the curved line of the camber-slip, a segment of a circle, and the sides, the inclination of the skewback of the arch, which is usually inclined about seven inches and a half from the upright of the reveal. The top and the bottom lines are then divided into an equal number of equal parts, and lines radiating are drawn as shown in the cut. The joints follow the curve of the camber-slip. a a a b b a b b b Mould. [Cut of the mould with the bevels set off upon it.] a represents the point at the top line of the mould, being a guide for the length of the brick; bb, the angles set off by the bevel. A larger, or what is called an irregular segment is cut in the same manner. A semicircular arch being struck from one centre requires but one mould, without the aid of the bevel, as all the bricks are alike and have their ends at the same angle. All arches, it should be observed, are collstructed on centerings of wood. In straight arches the camber-slip answers the purpose of a centre. Elliptical arches are cut like straight and semicircular arches, the ends like semicircular arches, and the centre like camber arches. Corbelling, or a projecting of brickwork, is often practised to gain space for flues and over corners of narrow streets. In steyning wells it is usual to employ brickwork where the soil is loose. For this purpose a centre is required, made with circular rings of wood boarded round the outside; upon these rings the bricks are laid. As the digger excavates the ground, the centre with the brickwork sinks and another is laid upon it till the whole work is completed. Mortar is the common medium employed to cement brickwork. This cement is composed of lime, grey or white, but grey or stone lime is the better; it is mixed with river sand, sea sand, or road sand, in the proportion of one of grey lime to two and a half of sand, and one of white or chalk lime to two of sand. In dry weather and for firm work the best mortar should be used, and the bricks should be wetted or dipped in water as they are laid, which makes them adhere firmly to the mortar. Brick-work in drains and foundations, where it is liable to be constantly wetted, becomes so firmly united with the mortar as not to be separated without the greatest difficulty. The work in this state is said to be water-bound. In building walls, they should be carried up level all round simultaneously, and not one part higher than another, lest in the shrinking there should be a settlement, which would cause the parts to separate. In laying the foundation of walls the first courses are always laid broader than the wall intended to be carried up: these courses are called the footings, and the projections are called set-offs: there are generally two inches in projection. Garden-walls are usually built with piers, projecting four and a half inches from the face of the work at every ten or twelve feet. These piers are turned in at the top like but tress-heads, and the top of the wall is finished with a course of brickwork on edge. When new walls are to be built to old it is usual to cut a chase or draw a brick at every other course in the old work and tooth in the new work. When it is intended to add walls to other buildings these toothings are left. The flues for chimneys are twisted to prevent their smoking [see HOUSE, in which a drawing represents a stack of chimney flues as built in London]: they are always chalked on the wall of a house to which another is intended to be added. The following are the substances of brick walls, as required to be built in London according to the Building Act of 14 Geo. III. c. 78. In first-rate buildings the external walls are directed to be built of two bricks length in thickness to the cieling line of first floor, and the party walls in the basement story two and a half bricks, and from thence to the gutter two bricks. In second rate buildings the party walls are two bricks and a half thick in the basement, and two in the first and second floors. The external wall has one brick and a half, and one brick in the two upper stories. The third-rate have the external wall one and a half brick thick in the basement and one brick above, and the party wall two bricks in the basement and one and a half brick above. The fourth-rate has one and a half brick in base ment of both party and external wall and one brick above in each wall. A rod of brickwork was taken from the original standard of 164 feet square, and consequently the superficial rod of brickwork consists of 2724 square feet; but as the was found troublesome in calculation, 272 superficial feet has been adopted as the standard for a rod of brickwork. The following is the method in practice for calculating the number of rods and feet in a brick wall, if of the standard thickness, which is 13 inches, or a brick and a half. Multiply the length by the height, and divide by 272, which will give the rods. If it is more or less than the standard thickness, multiply the surface by the half-lengths of brick in the thickness of the wall, divide the product by 3, and the wall will be reduced to the standard, which, if divided by 272, will give the work in rods or if the work is cubed, it must be divided by 306 to reduce it to rods, &c. For details of the value and measurement of brickwork, see Elsam's Perpetual Price Book and Nicholson's Dictionary. A rod of standard brickwork set with mortar will require 4500 bricks upon an average: the mortar required for the same is 1 cwt. of chalk or white lime with two loads of sand, or 1 cwt. of stone lime with 2 loads of sand. In walls a foot of reduced brickwork requires 17 bricks. A foot superficial of gauged arches requires 10 bricks. A yard of paving requires 82 paving bricks, or 48 stock bricks, or 144 Dutch clinkers laid on edge, or 36 bricks laid flat. The value of a rod of stock brickwork is from 11. to 14., according to the locality. If set in cement 187. is about the price. The weight of a rod of brickwork is calculated to be 15 tons, 7 cwt., 2 qrs., 1 lb., in the following quantities:- Among the most remarkable specimens of ancient brickwork are the masses on the Palatine hill and the baths of Caracalla The Roman brickwork in large works is excellent the bricks are very hard, and so firmly cemented, that they cannot be separated without the greatest difficulty. Great care has been shown in the execution of the work; and one building, still existing near the grotto of Egeria, has pilasters, cornices, modillions, dentils, and other ornaments finely cut in a yellowish brick closely cemented together and still in high preservation. The most recent specimens of antient Roman brickwork are the walls which surround Rome: there are also many specimens scattered throughout Italy. The bricks being generally thin and of the nature of tiles, this circumstance diminished the difficulty of constructing arches, of which the great arches of the Temple of Peace in the Forum Romanum are remarkable examples. The Tauk Kesra at Ctesiphon (about 18 or 20 miles from Bagdad) is perhaps the largest antient brick arch existing, being a semicircle 85 ft. wide, 106 ft. high, and 150 ft. long. (Ives' Voyage, &c., p. 289.) The worst bonded specimens of brickwork executed by the Romans are those formed of triangular bricks filled with rubble. The reticulated work, which is constructed with stones, is often bonded with courses of brickwork. In Pompeii columns constructed with bricks have been discovered in this city the brickwork of the public buildings has been very accurately executed. The brick dome of Santa Sophia at Constantinople is made of porous bricks, light enough to float on water. The brick towers of Bologna are stupendous piles of brickwork. London contains more brick buildings than any other city in the world, some of which are built of the best materials and by the best workmen : St. James's Square, in London, is one of the best specimens of brickwork in Great Britain. The most extensive arched brickwork in London is in the sewers. The Thames Tunnel is also a remarkable piece of arched brickwork; but the largest series of well-constructed arches yet seen in England is the new railway from London to Greenwich, which is not yet finished. The brickwork in Holland is very accurate. There are many curious brick fronts in Germany, especially in Hanover, and some architectural display in brickwork appears in several of the smaller Italian towns. But the most singular and beautiful brickwork is found in North Prussia, in the Marien Kirche at Brandenburg, the castle of the Teutonic knights, and a variety of other buildings. Brickwork was not common in London until after the great fire of 1666. There are early specimens of brickwork in some of the old baronial mansions, in which the chimneys are the most conspicuous features. But few of these houses are of greater antiquity than the time of Henry VII. and VIII.; and most of them date about the reign of Elizabeth. Hampton Court, built by Cardinal Wolsey, is a specimen of good antient English brickwork. One of the most elaborately carved specimens of English brickwork with which we are acquainted is a tomb in the church of Wymondham, Norfolk, which is in the early Italian style covered with grotesque ornaments. The practice of carving cornices, &c. in brick continued till about a century ago, when it ceased, owing to the more frequent use of stone. Inigo Jones used brick moulded cornices in some of his structures. BRIDEWELL, a name frequently given to houses of correction. The cause of its being so applied may be traced to the following circumstances. Before the Reformation, there were in London and various parts of the country wells termed holy wells,' whose waters were supposed to be endowed with peculiar virtues if taken at particular festivals or other times. Some of them in reality were medicinal springs. St. Bride's well, near the church of St. Bride, in Fleet Street, was one of the holy wells of London. In the vicinity of this well Edward VI. founded an hospital, which was afterwards converted into a receptacle for disorderly apprentices, in fact, into a House of Correction. The boys were distinguished by a particular dress, and were in the habit of attending fires with an engine belonging to the hospital. In 1755 a report was made to the governors respecting the unruly conduct of the Bridewell boys.' Their turbulence in the streets had become a great annoyance to peaceable citizens. From the time their peculiar costume was laid aside, their general conduct underwent an improvement. Bridewell Hospital is at present used as a receptacle for vagrants committed by the Lord Mayor and sitting aldermen; for apprentices sentenced to solitary confinement; as a temporary lodging for persons previous to being sent home to their respective parishes; and a certain number of boys are brought up to different trades. Houses of correction in different parts of the country which are called bridewells are so called in consequence of the hos pital in Blackfriars having been the first place of confinement in which penitentiary amendment was a leading object. BRIDGE, a construction of stone, wood, brick, or iron; consisting of piers, with either horizontal beams laid from one to the other, or with arches between the piers, on which a road-way is formed for passengers and vehicles. Parapets are elevated on each side of the road, and foot pavements, called banquettes, are raised for people on foot. There are still remaining bridges of great antiquity built by the Romans, but we are unacquainted with the earliest history of so useful a contrivance. The first makers of bridges may have taken their ideas from natural works similar to the bridge of Icononzo, in South America, or the Rock Bridge in Virginia, or from bridges formed by the fall of trees across small brooks and rivulets. There is no mention of a bridge in the Old Testament. Perhaps the oldest historical record of a bridge is that of the bridge of Semiramis, at Babylon [BABYLON], which consisted of piers, with beams laid horizontally from pier to pier. Some Chinese, and some South American bridges built by the Incas (the bridge of Capac Yupanqui, the Inca, over the Desaguadero, for example), are novelties in this kind of construction; the arch of the former being constructed of two pieces of stone cut to a quarter of a circle; and the latter being large suspension bridges made of rushes. The Chinese lay claim to a high antiquity for their skill in bridge-building by means of arches. The bridge of Fou-tcheou-fou, the capital of Fo-kien, has more than 100 arches. At Tsuen-tcheou fou there is a bridge with 300 stone piers built with angles to the river. The bridge at Suentcheou-fou, a shallow estuary, is 2500 Chinese feet in length and 20 in breadth. The road-way of this bridge is laid horizontally with huge blocks of stone on 252 stone piers, and on these other stones are laid across. The city of Chao-king, like some of the Dutch towns, has numerous canals, and in consequence numerous bridges, for the most part of one arch, and rising very high. At Tansi there is a freestone bridge of seven arches, the centre arch of which is about 46 feet wide. Chinese bridges have pointed, semicircular, polygonal and semi-elliptical arches. Their construction, which is curious, is described by Mr. Barrow. (See also DUHALDE, vols, ii. and iv. pp. 91, 357; and the Index.) The bridges in South America called bujaco are very narrow, and from the lightness of their materials, and being suspended, they'oscillate in a terrific manner. The width of these bridges often does not exceed 4 ft. 6 in. The Taribita bridge consists of a single rush rope, on which a kind of carriage is swung, and drawn from one side to the other by another rope attached to it and held by a person on the bank. (See also BOOTAN, p. 169.) The oldest stone bridges with which we are acquainted, several of which are still perfect and in use, are those built by the Romans. Their solidity and proportions prove that they must have been constructed on sound principles. The chief of these structures which still remain at Rome, are the bridges of Fabricius and Cestius, connecting the island of the Tiber with the city of Rome and the opposite bank; the Milvius, over which passed the Flaminian way; and the bridge of Hadrian. The Sublicius, an antient bridge at Rome, was built of wood; but the most remarkable wooden bridge constructed by the Romans was that thrown by Cæsar over the Rhine. It was built with a double row of piles, inclining to the course of the stream, and joined together at two ft. from each other: forty ft. apart from these was another similar row inclined against the stream. Long beams, two ft. thick, were fixed between the piles, and held fast at each end by two braces. The beams were joined by transverse pieces. The first double row of piles was protected by other piles beyond them, which served as buttresses, and were designed to protect the piles from timber floating down the stream. (See Cæsar's Commentaries, translated into Italian by Baldelli, with designs by Palladio, Venice, 1575; and also Commentarii, &c., Venetiis, 8vo. 1513, 1519, with a picture of the bridge over the Rhine.) The bridge built by Trajan over the Danube was the most stupendous work of the kind ever constructed by the Romans. (Dion. Cass., lib. lxviii. c. 13.) It consisted of 20 piers of stone, 60 Roman ft. broad and 150 ft., without the foundations, above the bed of the river; the width between each pier was 170 ft., and the piers were united by arches. The bridge of Narni, which is a fine specimen of Roman work, is constructed over the Nera, where it flows between two precipitous hills. This bridge originally consisted of | four arches, three of which are broken. The height of the arches was about 112 ft., and the width respectively 75, 135, 114, and 142 ft. 6 in. The Roman bridge and aqueduct, now called the Pont du Gard, over the Gard or Gardon near Nismes, consists of six arches at its base, the whole length being 465 ft.; a second series of arches, above these, extends 780 ft. to the slope of the mountains on each side; above this is a third series of 35 arches, smaller in size, extending 850 ft., which carries the water from the mountains. The entire height of this structure is 190 ft. Another ancient Roman bridge, that of the Tagus at Alcantara, in Spain, consisted of six arches raised 200 ft. above the river: the whole length was 670 ft., and the breadth 28 ft. [ALCANTARA.] An old bridge, near Brioude, over the Allier, in the dep. of Haute Loire, consists of one arch, 181 ft. wide, and 68 ft. 8 in. high from the water to the intrados of the arch: the breadth of the bridge is only 13 ft. Two remarkable bridge-aqueducts have been erected in modern times: one at Alcantara, near the city of Lisbon; the other, called the Ponte Maddelena, near the royal palace of Caserta, in the kingdom of Naples, to supply the fountains in the gardens of that edifice. The structure at Alcantara consists of 35 arches of unequal dimensions. The principal arch is 108 ft. 5 in. wide, and 227 ft. high; the other arches vary from 21 ft. 10 in. in width to 72 ft. The total length of the whole is 2464 ft. The Ponte Maddelena, like the Pont du Gard, consists of a series of arches, one above another, built between the slope of two mountains. The bridges erected by the Romans in the provinces served as models for the stone bridges which were erected after the dissolution of the empire, and it is to the conquests of this nation that N. and W. Europe is indebted for the introduction of so convenient a means of internal communication. But the finest examples of bridge architecture, which equal any that the Romans have left, and surpass all others in the world, are the five principal bridges of LondonBlackfriars' bridge, London bridge, Southwark iron bridge, and Westminster and Waterloo bridges. Many of the Russian bridges are constructed of wood; and in St. Petersburg the principal bridge is of boats. (See the Plan of St. Petersburg, published by the U. K. S.) When rivers have a rapid current, bridges of boats are commonly employed, as over the Po, in Italy. These bridges, called by the French, ponts volunts, are rudely constructed with a few boats attached to a rope, and moored in the centre of the stream: the bridge is moved by a rudder, and, assisted by the stream, is carried over to the other side. The oldest bridge now existing in England is the Triangular bridge at Croyland, in Lincolnshire, which is said to have been erected about A.D. 860, but with what view it is difficult, if not altogether impossible, to determine. It is obvious that utility was not the motive of the builder, though it may be allowed to claim the qualities of boldness of design and singularity of construction as much as any bridge in Europe. It is formed by three semi-arches, whose bases stand in the circumference of a circle, equidistant from each other, and uniting at the top. This curious triune formation has led many persons to imagine that the architect intended thereby to suggest an idea of the Holy Trinity.' (Nicholson's Dict.) Old London bridge, which has recently been removed, was the oldest structure of this kind in the city of London; and till about the middle of the last century, was the only means of communication, except by ferries, between Surrey and Middlesex. This bridge was begun in 1176, in the reign of Henry II., and finished in that of John, A.D. 1209. For several centuries it was covered with houses, which were at last removed. The bridge called Pont y Pridd, over the Taff, near Llantrissent, in Glamorganshire, which was completed in 1755, is a fine work. It consists of a single arch 140 ft. wide, forming the segment of a circle of 175 ft. diameter; the height is 35 ft. A bridge over the Liffey, near Dublin, built in 1792, consists of an elliptical arch 106 ft. wide, which rises only 22 ft. Venice contains a great number of bridges, but with the exception of the Rialto, they are all insignificant. The Rialto was begun in 1588, and finished in 1591, from the design of M. Angelo; it consists of one arch nearly 100 ft. wide, and 23 ft. from the water line; the width is 43 ft. This bridge is constructed of white marble, and the foundation is on piles. One of the lightest and most elegant bridges of Europe, the Ponte della Trinità at Florence (Map of Florence, published by the U. K. S.), consists of three beautiful elliptical arches. Dresden has a very large bridge of 16 arches over the Elbe. (See the Plan of Dresden, published by the U. K. Society.) Paris contains numerous bridges of stone, wood, and iron; of which the oldest is the Pont Neuf, and the most modern a chain or suspension bridge. The bridges of Paris are not remarkable for their length, nor generally for architectural beauty: most of them are inferior to many of the provincial bridges in England. The longest bridge in England, that of Burton-upon-Trent, is 1545 ft. in length, and has 34 arches. One great improvement in the practice of bridge-building, in modern times, is the construction of equal arches, by which a horizontal line of road is formed, and the inconvenient rise and fall in the carriage-way of the older bridges is avoided. The Pont de Neuilly, built between 1768 and 1780, by M. Perronnet, over the Seine, is, we believe, the earliest modern example of this kind of bridge. It has five equal arches, 128 ft. wide, and 32 ft. in height; the piers are 14 ft. thick, and the width of the bridge is 48 ft. the rise in 33 ft. is not more than 6 in. In 1771 another flat bridge of 13 semi-elliptical arches was built over the Allier, at Moulins; these arches are 64 ft. span and 24 high. The bridge of St. Maixence over the Oise, and the bridge of Orléans over the Loire, also approximate to a horizonal line in their road-way. The bridge of Orléans is 1100 ft. long. One of the finest flat or equal-arched bridges ever constructed is Waterloo bridge over the Thames, which was built by Mr. Rennie. Wooden bridges are much more common than bridges of stone, from the greater facility of constructing them of this material, as well as on account of their cheapness. Bridges built of wood, unsupported by upright posts, and sustained only by abutments at the ends, have been termed pendent bridges and philosophical bridges: such was the bridge of three arches formerly in existence at Walton-on-Thames. Palladio has described three methods of constructing these bridges. The small bridge of one arch over the Cam, at the back of Queen's-College, Cambridge, is of this kind. Among the wooden bridges of America, the Upper and Lower Schuylkill bridges near Philadelphia, and the bridge across the Delaware at Trenton, are perhaps the most remarkable. The chord line of the Upper Schuylkill bridge, called the Colossus, is 340 feet. The Lower Schuylkill bridge consists of three arches on stone piers; the centre arch has a chord of 195 feet, and the two side arches 150 feet each. The bridge over the Delaware at Trenton is a very singular construction of five arches, supported on light stone piers. The chord of the centre arch is 200 feet; the two arches on each side the centre, 180 feet; and the two abutment arches, 160 feet each. This bridge was erected by C. A. Busby, in 1819. A very accurately-engraved drawing of it has been published by Messrs. Taylor, of Holborn, to which the working drawings are attached. Wiebeking, a German engineer, has constructed some fine bridges of wood. One at Bamberg is 208 feet span. A great change in modern bridge-building has been effected by the introduction of iron and the use of chain or suspension bridges, the principles of which, it should be observed, were understood as early as 1615. See Scamozzi's Del Idea Archi. [CHAIN BRIDGE.] The most remarkable bridge of this kind is the Menai or Beaumaris bridge, near Caernarvon, which connects the island of Anglesea [The centre arch of the Menai or Beaumaris Chain Bridge-for dimensions, see end of the article.] with the main-land opposite. A similar bridge has been constructed over the Thames at Hammersmith, near London. Very similar to this bridge is the Chinese chainbridge on the high-way of Yunnan, in the province of Koeitcheou, the work of General Pan-ho. (Duhalde, vol. i. p. 60.) Suspension bridges have also been thrown over the Seine at Paris: the first that was erected there fell down almost immediately after its completion. Numerous bridges of this description have been made in Great Britain within the last 20 years, of which the late Mr. Telford con structed by far the larger part. The merit of having first employed iron in bridge-building is attributed to the English, but it really belongs to the Chinese. (Duhalde, vol. i. p. 60.) The first iron bridge built in England was erected in 1779 at Coalbrook-dale over the Severn: it consists of one arch upwards of 100 ft. wide, 'composed of five ribs, each rib formed of three concentric arcs, connected together by radiating pieces. The interior arc forms a complete semicircle, but the other arcs extend only to the sills under the road-way. These arcs pass through an upright frame of iron at each end, which serves as a guide, and the small space in the haunches, between the frame and the outer arc, is filled with a ring about 7 ft. in diameter. On the top of the ribs cast-iron plates are laid to sustain the road-way. The interior ring is cast in twopieces, each piece about 70 ft. long; and the total weight of metal used is 378 tons.' (Nicholson's Dict.) Since 1779 many iron bridges have been constructed in Great Britain, and some few on the continent. The largest iron bridge yet made is that of three arches, from the Southwark side of the Thames to Queen-street in the city of London. Mr. Telford proposed to erect an iron bridge of one arch only over the Thames at this place. Bishop Wearmouth bridge, which is also of iron, was erected between 1793 and 1796. It consists of a single arch 240 ft. span. The bridge over the Severn, at Buildwas, built by Mr. Telford, is a single arch 130 ft. span, and 27 ft. in height from the springing to the intrados. Vauxhall bridge over the Thames at London, is one of the lightest constructions in iron with which we are acquainted. Smaller bridges of iron are now common enough over narrow streams, and over the entrances of docks: they are sometimes of one leaf or part, and sometimes consist of two leaves. Those made of one leaf turn on a centre, or a series of balls or rollers: those which consist of two parts turn on a number of concentric rollers, which move between two circular castiron rings very nicely turned; each leaf or part has a flap, which lets down by a screw, and abuts upon the stone-work on either side, forming the whole bridge, when shut, into an arch capable of bearing any weight which can possibly pass over it.' (Nicholson's Dict.) A bridge of this kind at the London Docks, which weighs 85 tons, is opened and shut again in three minutes. The most recent bridge, and the largest yet constructed of this kind, is the bridge at Lowestoft in Norfolk, over the new cut which connects lake Lothing with the sea. The following are the dimensions of several of the principal bridges of Europe as near as we can ascertain them. Length and number of arches of a few of the principal Bridges of Europe and America. Feet. Arches. 900 5 Blackfriars' Waterloo Westminster Vauxhall Menai, the span of the centre arch Suspension bridge over the Severn at Buildwas 130 1 Sunderland iron bridge Coalbrook-dale iron bridge Burton-upon-Trent Bridge over the Liffey, Dublin 1700 19 1593 17 1100 Pons Senatorius, now Ponte Rotto, at Rome The Trenton, over the Delaware 716 9 Aliberti is perhaps the earliest writer on bridges, and he has been followed in a great measure by Palladio, Serlio, and Scamozzi. For information on bridges the reader may consult Mr. Gautier's work, Belidor's Architecture Hydraulique, and Perronet; also Bosset and Rion on bridgebuilding. Mr. Telford's work on bridges, which it is understood will be shortly published, is expected to contain much valuable information. Müller, Labelye, Atwood, Semple, Emerson, and Dr. Hutton, have also written on bridges. BRIDGE HEAD, or Tête de Pont, is a fortification covering that extremity of a bridge which is nearest to the position occupied by the enemy, in order, by securing the line of communication, to facilitate the advance of an army or protect its retreat. however the bridge-head is to be sufficiently capacious to serve as an intrenchment for the whole of an army, it may consist of a series of redoubts flanking each other reciprocally, and disposed on a curve line whose extremities rest on the riv.; and whatever be the nature of the work, when its capacity is considerable, it is recommended to have a redan or small fort immediately covering the bridge, with its faces so disposed that the fire from thence may defend the intervals between the exterior redoubts. This will also serve as a retrenchment in which, after the main body of the army has passed over the riv., a small division may be stationed to protect the retreat of the troops employed in defending the principal works. The passages by which an army or detachment, in retreating, enters a bridge-head the re-entering angles of the work, if such there be, where consisting of a continuous parapet, should be situated in they may be well flanked by crossing fires from the collateral faces: and they should be defended by a direct fire from traverses in the interior. To prevent the enemy from advancing towards a bridge along the bank on which the works are situated, that bank both on the right and left of the bridge should be well defended by a fire of musketry or artillery; consequently the parapets adjacent to the riv. should be as nearly as possible perpendicular to its direction. And it is evident that the most favourable situation for a military bridge is at a bend of the riv. where the concavity is towards the enemy's position; for the fortifications will thus conceal the bridge from his view; and on either side of the work the brisures intended to defend the ground immediately in front may be directed towards the riv., by which they will be secure from an enfilading fire of the enemy. Should any commanding ground permit the enemy to direct a plunging fire of artillery upon the bridge or within the works, and should it be found impossible to give to the parapets a height sufficiently great to intercept that fire, batteries or redoubts must be constructed in convenient situations on the rear side of the river, in order, by their fire, to prevent the enemy from occupying that ground. Those works will also serve to defend the faces of the bridge-head when attacked; a traverse also should be raised on the same side of the river perpendicularly to the length of the bridge, in order to enfilade the latter in the event of the enemy attempting to force a passage over it before it can be destroyed. When there are islands in the river it is advisable to establish the bridges so that they may connect the islands with the opposite banks, for thus the bridges, being shorter than if they were to extend quite across the river, may be be facilitated and more effectually defended. There should more numerous; consequently the passage of the river will be a separate head for each bridge besides the general head on the farther bank; and any collateral islands, if such there be, should be fortified, both to prevent the enemy from occupying them and thus obtaining a view of the bridge, and to afford the means of flanking the principal When a bridge is built across a riv. which runs through or along one side of a fortified town, the ramparts of the BRIDGNORTH, a bor. and m. t. in the S.E. part of town in the one case, and those constructed for the defence Shropshire, on the Severn, 19 m. S.E. by E. from Shrewsof any buildings beyond the riv. in the other, may be con- bury, and 139 N.W. from London. The town lies on both sidered as constituting the bridge-head; and then the works sides of the Severn, which are connected by a bridge; but enter into the class of permanent fortifications. In other the larger portion is on the W. bank, built on a hill which circumstances their form depends upon the nature of the rises 60 yards from the bed of the river. The bor. and ground, and upon the importance of the pass to be secured. town were co-equal, consisting of the parishes of St. LeoIf a retreating army is likely to be exposed to a serious nard and St. Mary Magdalen, but certain liberties were also attack when about to cross a riv., the works must be strong under the jurisdiction of the bor..magistrates. The parliaenough to keep the enemy in check, and sufficiently ex-mentary bor. was extended by the Reform Bill, and now tensive to contain the whole army, till the passage can be effected. The simplest kind of bridge-head is one which has the form of a redan; that is, a breast-work, with two branches disposed on the plan like the sides of the letter A, and terminating on the bank of the riv. But when a more perfect defence is required, the bridge-head may have the figure of a horn-work, or of a fort with bastions; the arca to be occupied by the defenders being inclosed, except at the gorge or riv. side, by the rampart or breast-work. When includes the parishes of Quatford, Oldbury, Tasley, and extended boundary was 6171, that of the old bor. 5298. Astley-Abbots. In 1831 the pop. comprehended within the origin. The first known charter is one of the 16th John, Bridgnorth, antiently Bruges, is stated to be of Saxon confirmed by subsequent grants, by which special privileges were secured to the inhabitants. By the Municipal Reform Act the town council consists of 4 aldermen and 12 councillors, but the town is not divided into wards. The bor. returns two members. In the par. of St. Leonard there |