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with a varying proportion of other mineral matters, chiefly free silica (sand), iron, lime, magnesia, and potash. Great advantage is derived from digging clay in autumn, and exposing it all winter to the disintegrating action of frost. This is not always attended to, but when neglected, the bricks made from it are apt to be unsound, and faulty in shape. The next process is that of tempering or mixing the clay into a homogeneous paste, which is sometimes done by the spade, but more commonly in the pug mill (see article Pottery) or by crushing between a pair of rollers; often, indeed, both are employed. In making bricks by the old hand process, the shape is given by a mold either entirely of wood, or of wood faced with metal, and without top or bottom. This admits of the clay being pressed into it by a tool called a plane, which is also used to produce an even surface on the upper and lower beds of the brick, by working off the superfluous clay. Sand is used to part the wet clay from the mold and the table on which it rests.
Although hand-made bricks are still very common, yet machinery is now always employed when large quantities are required. Brick-making machines are of two leading kinds; one class of them being constructed to work the clay in a wet plastic state, the other class requiring it to be in a semi-dry condition. Of the two sorts, the wetclay machines are the simpler, cheaper, and can be worked by less-skilled workmen. On the other hand, the dry-clay machines, which make the bricks by forcing the clay into molds by strong pressure, shorten the process, as no time is required for drying them. The bricks so made, too, are not only of a more perfect shape, but they can be molded into any form, and may even be made highly ornamental at a very slight additional cost.
As might be expected, both the dry and the wet-clay machines of different makers vary considerably in their details. The general plan on which most of the wet-clay machines work is as follows: The machine is driven by steam, and the clay is fed by a hopper into a pug-mill, on the central shaft of which strong pugging blades are placed in a spiral manner. These prepare and force the clay out at the bottom, whence it passes over the carrying rollers to the pressing rollers, which force it through a die in a rectangular stream, so exactly shaped to the required size that nothing more is necessary than to cut it into single bricks by wires. These are set in a rocking frame, which can be so adjusted as to cut the bricks on the square or at an angle; the one plan being adopted when the clay is at rest, the other while it is in motion. When double-ended, the clay is forced out at opposite sides of the pugging cylinder, and there is then, of course, a cutting-table at either side, instead of only one. Some of these machines are provided with a pair of powerful crushing rollers, which reduce any hard lumps or stones before the clay enters the pug-mill. One of the best known wet-clay machines is that made by Clayton, Son & Co.,
London. When of a size which can be worked by a steam-engine of 16-horse power, it produces from 20,000 to 30,000 bricks per day, and its price in 1871 was £330. Drain tiles are made by the same kind of machinery, with a peculiarly constructed die, so as to make clay into a hollow tube; so also are hollow bricks, with again an alteration in the shape of the die. Hollow bricks, having less body than those which are solid, are more easily and usually more thoroughly fired. On account of this, as well as by reason of their admitting of a current of air through them, they form, as a rule, dryer walls.
The green bricks, after being carefully dried, either in the sun or by artificial heat, are usually baked in a kiln with a suitable arrangement of fires and flues. Kilns are of many forms, and the time required for firing in them varies from 40 to 60 hours for common red and white bricks, while for some fire-bricks 150 hours are necessary. Where kilns are not used, bricks are burned in clamps, the clay requiring to be mixed up, in the process of tempering, with a quantity of ground coal sufficient to burn them. A good test of the character of a clay is obtained by the result of firing. The average contraction in the kiln for prepared clays is 74 per cent. If a brick contracts much more than this, the clay is too fusible; if less, then it is likely to be of an open porous body, which retains its shape well during the firing process.
All brick clays contain iron, and the color of a burned brick almost entirely depends on the amount of it which is present; thus clays containing less than 1 or 14 per cent of iron, change in the kiln to various shades of cream color and buff, whilst those containing more than 2 per cent, range in color from yellowish-fawn to dark red. Blue bricks are made from the same clay as the red, by controlling in a peculiar way the supply of air in firing, and by carrying the heat slightly further. It is asserted by some that the red is changed to the black oxide of iron in the process.
Fire-bricks are made from clay as free as possible from oxide of iron and alkaline substances, so that there may be no tendency to fuse in the kiln, however high the heat. Fire-clays are abundant in the coal-measures, some of fine quality being found about Newcastle and Glasgow, but the most celebrated is that of Stourbridge, which is exported to all parts of the world. See FIRE-CLAY.
Much attention has been paid of late years to the manufacture of fine bricks and terra cotta, which is only another name for ornamental bricks of various shapes, or architectural enrichments of the same material. The effect of some of the public build. ings recently erected in London and elsewhere, in which terra cotta has been used, is really beautiful. Although it cannot be said to equal sandsone in appearance, it has yet the advantage of giving a much greater variety of color, and is infinitely better and more enduring than a facing of stucco or cement.
The duties formerly levied on bricks were wholly repealed in 1850.
BRICK (ante), made in the United States in nearly the same manner as in England. The size varies in various sections from 7 to 84 in. long, 4 to 4! wide, and 2 to 21 thick, and is therefore smaller than that of English B., which are usually 9 by 41 and 25. Philadelphia pressed bricks are in great demand for outer or front walls in consequence of their perfection. Immense quantities of B. are made at Haverstraw and other places on the Hudson river. Excellent fire-brick are made at South Amboy, N. J.; at Athens, on the Hudson; at Chicago, Peoria, and other places. Milwaukee bricks have a pleasing yellowish cream color; and these, with others variously colored in the manufacture, find much favor for outer walls. Bricks are found to stand fire better than stone.
BRICKLAYING-BRICKWORK. The material of which a town is built depends mainly on the geology of the surrounding district. In a mountainous country like Scotland, cities of stone, such as Edinburgh, Glasgow, and Aberdeen, naturally abound; while London and most of the great towns of England, situated in alluvial valleys and plains, are built of bricks derived from the alluvial clay beneath and around them. In Holland, where the whole country is but the delta of the Rhine, and no stone is to be found, brick is universal, even to the paving of the streets.
The standard size of English bricks being 9 in. by 4d, the thickness of walls is regulated thereby. They are either half-brick, i brick, 17, 2, 3, or 4 bricks in thickness. In moderate-sized modern English houses, the inside partition-walls are usually half-brick, the outer walls, 1 or 11. In larger houses of superior construction, a thickness of two or three bricks is sometimes used. This latter thickness is seldom exceeded, except in large public works. Modern brick-houses are, for the most part, far less substantial than those erected by our forefathers. Building leases being usually granted for ninetynine years, at the expiration of which term, the whole properiy reverts to the freeholder, the object of the builder is merely to make a house that shall stand for that period, and not to expend any money for the sake of further stability. Garden-walls are commonly built but half-brick in thickness; these, however, are strengthened by 9-in. 'piers at intervals of 10 or 12 feet. In laying the foundations of walls, the first courses should be thicker than the intended superstructure, and the projections thus formed, usually of quarter brick on each side, are called “set-offs.” Before laying walls of houses, trenches are dug, and the foundation tried with a crowbar or rammer. If it is found to be loose, and the looseness due to superficial soil, this is removed, and its place supplied with fragments of stone and old broken bricks, which are closely rammed together. In some cases inverted arches of brick are built for foundation, or a stratum of concrete laid down. See CONCRETE.
Mortar composed of lime and sand is the common cement for brickwork. It should be equally and carefully applied; and the bricks wetted, in order that the mortar may adhere more firmly, by being absorbed into their pores. The force with which good mortar is capable of adhering to bricks is very remarkable. It is found to be the greatest in old structures that have been exposed to the continuous action of water. Such B. is said to be "water-bound” by workmen, and can scarcely be separated without breaking the bricks.
A fundamental principle to be rigidly observed in laying all kinds of brick is, that no two contiguous perpendicular joints shall fall immediately below each other, or, to use the bricklayer's phrase, the work must “ break bond.” The mode of arrangement of the bricks to effect this is called the bond; a layer or stratum of bricks is called a course. Bricks laid with their lengths in the direction of the course, and their sides to the wallface, are called stretchers; those laid across the line of the course, with their ends forming the wall-face, headers; a layer of headers; a heading course, of stretchers, a stretching course.
The two kinds of bond almost exclusively used in England are the English and Flemish bond. English bond consists of alternate stretching and heading courses; Flemish bond, of a stretcher and header laid alternately in each course English bond is the strongest; Flemish bond, the more ornamental; and they are used accordingly. There are two other kinds of bond occasionally used-herring bond, and garden-wall bond. The former is applied to form the core of trick walls, where Flemish bond is used for the facing. A course of bricks is laid obliquely at an angle of 45° to the face of the wall; then above it, another course at the same angle, but inclined in the opposite direction, so that the joints may cross the first. This is considered to add to the strength of Flemish bond, but is objectionable on account of the triangular inter stices necessarily left between the oblique bricks and the bricks of the facing. Garden. wall bond is only used for 9-inch walls, and formed by laying three stretchers and one header, and so on in each course. In order to strengthen Flemish bond, bands of hoopiron are sometimes laid flatwise between the courses. This “hoop-iron bond” has superseded the old practice of using bond-timbers, which were inserted the whole length of the wall. The hoop-iron should be slightly rusted, to secure the complete adhesion of the mortar.
In constructing arches of brick-work, much care and skill are required. A wooden centering is always used; and when very rude work only is required, common bricks are laid upon the centering, and the gaping interstices at the upper ends tilled with rough brick wedges. For better work, each brick has to be properly beveled, according to the curve. When semicircular arches are made, all the bricks require an equal bevel, and therefore bricks molded uniformly to the required angle may be used; but for other curves and for flat arches, each brick has to be separately shaped by the bricklayer. In order to do this, a drawing of the required arch is made of the full size on a board; the bricks are laid upon this side by side, and shaped to the lines of the drawing; they are then transferred to their corresponding place in the structure. The bricks are first rudely shaped by the brick-are, then finished on che rubbing-stone, a piece of roughgrained stone about 20 in. in diameter. In all kinds of B., the walls should be built up level throughout, in order that the settlement may be equal. An unequal settlement may produce a rupture of the wall.
B. is measured by the rod or by thousand. A rod contains 272 sq.ft. of standard thickness—that is, 11 brick. This is equal to 306 cubic ft., and will, on an average, require 4500 bricks, allowing for waste. The weight of a rod of B. containing 4500 bricks, 27 bushels of lime, and 3 single loads of sand, is about 13 tons. The bricklayer is always attended by a laborer or hodman, who carries his bricks and mortar in a * hod"-a triangular wooden box, open at the top and one end, and supported on a round leg, by which the hodman holds it on his shoulder. A bricklayer's wages are · considerable higher than those of the hodman. The laborers are generally Irishmen.
The surface of brick-work is sometimes ornamented by pointing. This is done by raking out the mortar of the joints to a small depth, and filling up again with blue mor. tar, and marking the courses with the edge of the trowel. This is called flat-joint pointing. When the courses are marked by a neatly pared raised line of white plaster of about half an inch in thickness, laid upon the blue mortar, it is called tuck or tuck-joint pointing. Colored bricks, as a means of external ornament, have been extensively and most effectively used in n. Italy and Germany. The works of Mr. Ruskin, Mr. Gally Knight, Webb's Continental Ecclesiology, Street's Brick and Marble of the Middle Ages, and Fergusson's Hand-book of Architecture, may be consulted for illustrated examples of these.
Chromatic brick-work is now becoming very extensively used in England, especially by architects who are endeavoring to revive the style of architecture called by them. selves English Gothic, and by some others Venetian Gothic, in which the pointed arch, formed of colored bricks, forms one of the prominent features. These architects maintain that, as they are compelled to construct with B., it is more honest to use bricks ornamentally, than by means of stucco to obtain an external imitation of stone; and as B. admits of but little ornamentation in relief, they use variation of color, of which B. is peculiarly susceptible, and thus produce a sort of architectural mosaic. The eloquent and popular advocacy of these views by Mr. Ruskin, and the skill and enthusiasm with which many young and rising architects are carrying them out, seem likely to bring about a great development, almost amounting to a revolution in English domestic and ecclesiastical architecture.
BRICOLLE. See BALLISTA.
BRIDAINE, JACQUES, a French home-missionary preacher, 1701-67. Though a strict Roman Catholic in principle, he frequently advocated the cause of the Protestants with great boldness, and displayed personal kindness to many who were suffering persecution. He made more than 250 journeys in all parts of France, and became universally popular. His sermons and spiritual songs, or hymns, have been printed.
BRIDE-BRIDAL. The word bride (the radical signification of which is thought by some to be appropriated," "owned ") is common to all the Gothic languages, and also to Welsh (Ger. braut, Welsh prod), and signifies betrothed or newly married. Alone, the word denotes the newly married woman; with the addition of the syllable groom (a corruption of guma Lat. homo, a man), it denotes the newly married man (Ang. Sax. brydguma, Ger. brautigam). In Welsh, priod-fab (betrothed youth) is bridegroom, and priod-ferch (betrothed maid) is bride. Bride is the root of a variety of terms connected with marriage, as bride-favors, bride-cake, etc. Bridal is for bride-ale (Ang. Sax. brydeale), the, marriage-feast. Bridemaids, or attendants on brides, appear to have been in use among the Anglo-Saxons, and are mentioned in early accounts of marriage ceremonies. A part of their duty consisted in dressing and undressing the bride. Bridemaids, as mere ceremonious attendants at marriages, are still in use in England. The husband had an analogous body of attendants, called bridegroom-men; but they have disappeared in modern usage, and their only representative is one confidential friend in attendance. In Scotland, this personage is called the best man. One of his duties is to pull off the bridegroom's right-hand glove, while one of the bridemaids does the same service for the bride, when the pair are requested to join hands.
BRIDE-FAVORS are small knots of white ribbons, which are pinned to the breasts of all who are in attendance at weddings, nor are even the postboys and their horses' heads left undecorated with these gay trappings. The origin of the bride-favor is said to be the true-lovers'-knot-something symbolical of the union of hearts and hands on the
occasion. In various old plays and poems there are allusions to bride-favors or ribbons, as that in Herrick's Hesperides :
What posies for our wedding-rings,
What gloves we'll give and ribbonings The BRIDE-CAKE is also symbolical in its origin. * The ceremony used at the solemnization of marriage among the Romans was called confarreation, in token of a most firm conjunction between the man and wife, with a cake of wheat or barley. This, Blount tells us, is still retained in part with us, by that which is called the bride-cake used at weddings.”—Brand's Popular Antiquities. The old English and also Scottish custom of breaking a cake over the head of the bride on entering her new dwelling, perhaps points to a usage of the most remote antiquity-the sprinkling with wheat as a token of plenty. In modern times, the bride-cake is a stately piece of confectionary, consisting of a rich cake as a basis, on which is reared a castellated structure, with various fanciful devices, the whole being covered with a preparation of white sugar. This fabric is cut up and given in pieces to the guests, as part of the wedding jovialty.
BRIDE'WELL, a well between Fleet street and the Thames, dedicated to St. Bride, which has given its name to a palace, parish, and house of correction. A palace, described as a stately and beautiful house,” was built here, in 1522, by Henry VIII., for the reception and accommodation of the emperor Charles V. and his retinue; and king Henry himself also often lodged here, as, for instance, in 1525, when a parliament was held in Blackfriars; and in 1529, the same regal personage and his queen, Catharine, lived in the B. while the question of their marriage was argued. In 1553, Edward VI. gave it over to the city of London, to be used as a workhouse for the poor, and a house of correction “for the strumpet and idle person, for the rioter that consumeth all, and for the vagabond that will abide in no place.' Queen Mary having confirmed the gift, it was formally taken possession of in 1555 by the lord mayor and corporation. The B. was afterwards used for other persons than the class above named, and at last became a place of punishment, as it now is. As a house of correction, it is not under the sheriff's charge, but is governed by a keeper wholly independent of that officer.
By the 15 and 16 Vict. c. 70 a new house of correction is established for the city of London. See CORRECTION, HOUSE OF.
BRIDGE (Ang.-Sax. brycg; Dutch, brug; Ger. brücke) is a structure for carrying a road over a stream, river, ravine, low ground, or other impediment to its course. A bridge for carrying a canal or other water-course, is called an aqueduct (q.v.); one for carrying a railway is sometimes called by the recently coined, though not very correct, word viaduct (q.v.). Bridges are formed of stone, brick, cast-iron, or timber arches; of timber beams or frame-work, supported on piles or on masonry; of iron rods or chains, in which case they are called suspension-bridges; of lattice-work; or of cast or wrought-iron girders. Sometimes a combination of beams and suspension-rods is used. Of late years, the plan of tubular or hollow wrought-iron girders has been frequently and successfully employed, the first great example being the Britannia bridge (q.v.).
Bridges are either fixed or movable. Of movable bridges there are various kinds. Flying-bridges and floating-bridges are, in fact, mere ferry-boats (see FERRY) with gangways attached, and other provisions for safe and ready transport, and which are drawn across the stream by ropes. Draw-bridges and swing-bridges are constructed in two parts, that turn on pivots-in the former, the parts are lifted vertically; in the other, they are moved round horizontally. A sliding-bridge runs backward and forward on wheels or rollers. Another kind is much in use in low districts like Norfolk, where the water flows lazily, and almost on the land-level. These are sometimes called pontoon-bridges, from the movable roadway being balanced at a small height above the water-level on a pivot working in a large pontoon or hollow cylinder sunk in the bed of the river—the ends of the roadway of the B., when laid across the river, resting freely on piers on either side. There are several such bridges in use over the Ouse. The pivot is set in the center of the stream, and, when necessary, the B. is turned round on it hy machinery, till it lies parallel to the banks, and permits the passage of barges on either side. In a flat district, these bridges are exceedingly appropriate. See also BRIDGE, MILITARY.
Convenience must have led men in a very rude state of society to form bridges, in order to the easier communication between districts separated by rivers. On most streams there occur fords, but often these are not to be found where they would be most desirable. The most rudimentary form of a B. may be assumed to be a series of stepping-stones, such as are yet almost everywhere to be found on river-courses at some point. Large stones deposited in the streams at the shallows or fords, would first give a chance to a passenger of getting across dry shod; by and by, where one or two stones were wanting to complete the steps in the passage, they would be supplied. Next, it would naturally occur to give greater security to the passage, by laying planks or trees across the stepping-stones, so as to avoid the risks attending stepping or leaping from the one to the other. In the arrangement of planks resting thus on stones, we have the first advance in the art of bridge building, the suggestion at once both of piers and roadways; and beyond this stage, the art would appear not to have advanced for a very long period. From the Greeks, we have accounts of bridges built by Semiramis,
Darius, Xerxes, and Pyrrhus; and in Egypt, necessity early compelled the formation of bridges in connection with the canals constructed for the purpose of irrigation. But all these would appear to have been rudimentary in form, and to have consisted simply of piers, with the intervals between them spanned by beams of timber or large Hat stones. Sometimes boats moored in the stream served the purpose of piers, as was the case with the famous B. of Xerxes across the Hellespont. Bridges of boats are in use to this day. The principle of the arch was long known before it was applied to the art of bridge-building. See ARCH. That application we owe to the Romans, whose first great work in which the arch was employed, the Cloaca Maxima (q.v.), is referable to the time of the Tarquins. The Ponto de Rotto, or Senators' B. (127 B.C.), erected by Caius Flavius, appears to have been the first instance of its application to bridges. In the course of the great engineering undertaking of the Roman empire under Augustus Cæsar for the formation of roads and supply of water to Rome, its application became general; and afterwards, the empire baving extepded its bounds, the necessity for ready communication between its provinces, led to the erection of numerous splendid bridges therein, many of which, indeed, surpassed in their greatness those of Rome itself. But although the Romans have unquestionably the merit of having originated the art of bridge-building proper in Europe, yet it seems doubtful whether the principle of the arch was not applied by eastern nations to bridge-building long before the dawn of the greatness of the Roman empire. The Chinese are said to have been before the west in this as in other arts, though the antiquity of some of the bridges on which this assertion is rested may well be doubted, considering the uncertainty which pervades the chronology of that extraordinary people.
It is inipossible here to trace in detail the progress of the art. For a long time after the decay of the Roman empire, it made no progress. It revived in the 11th c., but again languished to the beginning of the 18th, when the formation of the corps of the Ponts et Chaussées in France favored its further growth. Henceforth, many splendid bridges were erected both in Britain and the continent. In 1775, Mr. Pritchard of Shrewsbury, introducing the use of cast iron in the erection of bridges, originated a valuable style of construction. The genius and works of Telford bring us to the present time. Within half a century, the use of steam, the development of the canal system, and the necessity especially for railway-bridges, with the immense amount of capital at the disposal of engineers for purposes of bridge-building, have caused a rapid evolution of all the principles and possible modes of the art. Among the new forms called forth within the century by the increasing demand for facilities of communication, are the suspension B., the wrought-iron girder and tubular bridges, and the lattice-bridges. Several of the new bridges over the Thames are models of engineering skill and taste. The Menai and Britannia bridges were regarded when erected as perfect marvels of the art, and yet they have since been surpassed. In America, the B. of Trenton, over the Delaware, the great Portage viaduct, and the Niagara suspension B., are equal to any similar works in the world. The Tay B., opened in May, 1878, is the longest (2 m. in length) and perhaps the greatest achievement of modern engineering skill. The variety of complex structures of wood and of iron that now span streams and hollows is endless. For some of the more important forms, see FRAME, LATTICE, TUBULAR, and SUSPENsion Bridges. What follows here, relates chiefly to arched or masonic bridges, and is confined to the more general and obvious conditions which such bridges must fulfill, avoiding the mechanical theory of their stability as too abstruse for popular exposition.
An arched B. rests between masses of masonry on opposite sides of a river, called its abutments (q.v.). The intermediate points of support of the arches are the piers (q.v.), which are rarely built so strong as to be able of themselves to resist the lateral thrust of the arches resting on them, if the thrust of one arch did not counteract that of another. The arch itself is the curved construction between adjacent piers. The chief terms used in speaking of the arch itself are explained under ARCH. In addition, may be noticed the spandril, the name given to the filling in above the extrados to the roadway. The chord or span is the distance between the piers; while the rise of the arch is the perpendicular distance between the level of the springing and the horizontal through the key.
When a B. has to be erected, the question of what form it should be, falls to be settled by a variety of considerations. Regard to appearance affects the question, but the material points are its sufficiency for the purposes for which it is intended, and its security and durability The nature of the embankments and of the soil in the water-bed, together with the nature of the water-shed, or country drained by the stream, may make it necessary that the B. should not be an arched bridge at all, but a suspension or tubular bridge. But if it is to be an arched B., then the most important questions respect the number of its piers and the form of its arches. If vessels must be free to pass under it, the arches must be lofty, and the abutments high; so also must they be if the river is exposed to sudden elevations of its level by floods. Formerly, a prejudice existed against laying a B. across a stream at any other angle than at right angles to its course. The reason was, that, the theory of the skewed arch (q. v.) being unknown, the obliquity of the B. to the water-course involved a corresponding obliquity of its piers to the water, which greatly increased the risk of the B. suffering from floods. But the skewed arch allows a B. to be thrown at any angle across a river, with its piers all parallel to the