thorne. In 1854 he was appointed chief of the bureau of provisions and clothing, the duties of which he performed for nearly 15 years, including the whole period of the war. In 1873 he was retired as pay-director with the relative rank of commodore. He wrote some valuable reminiscences, entitled 'Personal Recollections of Nathaniel Hawthorne' (1893).

Bridge, Sir John Frederick, English organist and composer: b. Oldbury, Worcestershire, 5 Dec. 1844. He was organist of Trinity Church, Windsor, Manchester Cathedral, and in 1875 became full organist of Westminster Abbey. He was also made professor of harmony at Owens College, Manchester, and afterward professor of harmony and counterpoint at the Royal College of Music. Among his works are the oratorio, Mount Moriah'; the cantata, 'Boadicea'; the cantata, Callirhoë'; the oratorio, The Repentance of Nineveh'; etc. He has set many hymns to music, notably Gladstone's Latin version of Rock of Ages.'

Bridge, Joseph Cox, English musician: b. Rochester, England (brother J. F. Bridge, q.v.), 16 Aug. 1853. He studied under his brother and John Hopkins. From 1871-6 he was organist of Exeter College, Oxford, and in 1879 became organist of the Cathedral of Chester, The music-festival of that city owes its revival to him. Most of his works are for church use. Among them are: a Magnificat, a Nunc Di

mittis, and the oratorio 'Daniel.'

Bridge, a game of cards. In Turkey and Egypt it has been known for some time, but is played much more scientifically in England and the United States, where it was introduced in the last decade but one of the 19th century. It is played with one pack of cards, and the four players are styled the dealer, the leader, the dummy, and the pone. Bridge is allied to whist, and like that game is played in more than one way. See De La Rue, The Laws of Bridge' (1889); Foster, 'Bridge' (1901); Dunn, 'Bridge, and How to Play It' (1901); Steele, 'Simple Rules for Bridge' (1902).

Bridge, a structure supporting a roadway, designed to afford communication between the banks of a river or ravine, or to cross any open space. Bridges were formerly made of wood, brick, stone, or iron, but steel is now rapidly displacing these materials, except for the construction of bridges of minor impor

tance.

History of Bridges.- Stepping-stones in shallow rivers, connected by planks, exhibit the incipient principles of piers and arches which science has brought to their present perfection. In deeper rivers an accumulation of stones would form a loftier pier; and where the openings were sufficiently narrow, and the slabs of stone sufficiently long, or the art and strength of the untaught architect sufficient to the task, a stone roadway was formed from pier to pier.

nese.

structed such bridges about 536 B.C., Darius Hystaspes about 490, and Xerxes about 480 B.C. Bridges of stone or brick seem to have been first used by the Romans; there were none erected in Greece till after the Roman conquest. No people of the ancient world carried the power of rearing the stupendous arch and the magnificent dome to such an extent as the Romans, who are supposed, however, to have derived their first knowledge of the art from the Etruscans, and in the construction of stone bridges the highest rank must be conceded to this indefatigable people. The bridges of ancient Rome were eight in number. The first is said to have been one spanning the Tiber between the Janiculum and the Aventine Mountain, built by or under Ancus Martius, and famous for its defense by Horatius Cocles. One or two of these bridges are still standing; that called Ponte Fabricio having been built 62 B.C. One of the finest Roman examples was the bridge built by Augustus over the Narni, the vestiges of which still remain. It consisted of four

arches, the longest of 142 feet span and over 100 built by Trajan over the Danube, 115 A.D., and feet high. A still more remarkable bridge, Hadrian. The most celebrated bridges of the 4.770 feet long, was destroyed by his successor Romans were not generally, however, distinguished by the extraordinary size of their arches or the peculiar lightness of their piers, but by their excellence and durability. The span or chord of their arches seldom exceeded 70 or 80 feet, and the versed sine or height was nearly half of the chord, so that they were mostly semicircular, or constituted a segment nearly of that form.

Among the most celebrated bridges built subsequently to the destruction of the Roman empire are those of the Moors in Spain, who imitated and rivaled the best constructions of the Romans. The bridge of Cordova, over the Guadalquivir, is an eminent example of their success. The bridge over the Rhone at Avignon, begun in 1176, and now represented by a picturesque fragment, is one of the most ancient bridges of modern Europe. It was built by a society or order called the Frères Pontiers, or "Brethren of the Bridge." It was composed of 19 arches. The length of the chord of the largest was 110 feet 9 inches, and its height 45 feet 10 inches. Of the nations of modern Europe the French were among the first to carry the art of bridge-making to its present perfection. The constructions of Perronet, who was chief engineer of bridges and highways in France under Louis XV. and Louis XVI., have never been surpassed. Among them were the bridges of Nogent-sur-Seine (1766-9); Neuilly (1768-74); Louis XVI., at Paris (1787-92). The bridge at Neuilly consists of five arches, each 128 feet span and 32 feet rise.

In Great Britain the art of building bridges appears to have been introduced by the Romans. For special mention of celebrated stone bridges in the United Kingdom, see Stone Bridges, below.

bridge was that thrown by Julius Cæsar across the Rhine, as described in his Commentaries. Germany was the school for wooden bridges, as Britain for those of iron. Perhaps the most celebrated of all wooden bridges was that which spanned the Rhine at Schaffhausen in Switzerland. This had a span of 364 feet, and was 18 feet broad. It was designed and executed by J. Ulric Grubenman, a village carpenter of Teuffen, in 1758, and was destroyed by the French in 1799.

Bridges of timber were formerly much used in the United States and Canada; and many magnificent and elaborately planned structures carried American railroads across rivers and ravines, often at enormous heights. But with the exception of some insignificant spans, steel, as before mentioned, has almost ousted wood.

Stone Bridges.-The theory of stone bridges involves mathematical demonstrations and calculations of the greatest complexity; the properties of the arch, the thickness of the piers, and the force of the water form separate elements in the computations. The arch is a series of wedge-formed bodies cemented together and rendered coherent by mutual pressure, the first and last being sustained by a support or abutment. The centre arch-stone or voussoir (a French term) is the highest part or crown of the arch, and is called the "keystone." The interior surface of the arch is called the "intrados," the part immediately under the keystone is called the "soffit," the remaining portions the "flanks." The term soffit, however, is sometimes used synonymously with intrados. The exterior surface is called the "extrados," or "back of the arch." The points of junction between the flanks and the abutments are called the "springings"; the distance between them horizontally is the "span"; the perpendicular from the soffit to a straight line drawn between them is called the "rise," or height of the arch. The extreme supports of the arches at the ends are called "abutments"; the solid parts between the arches, piers, and the fences on the sides of the road or pathway, "parapets." It has been found that in the construction of an arch the slipping of the stones upon one another is prevented by their mutual pressure and the friction of their surfaces; the use of cement is thus subordinate to the principle of construction in contributing to the strength and maintenance of the fabric. The line of resistance of the materials forming any structure, whether straight or curved, being capable of geometrical calculation, it can be determined beforehand whether this line will fall within or intersect each successive joint of the structure; if it does, the mass will not be liable to turn over on the edge of any particular joint. By a more exact calculation of the line of resistance, even the slipping of one joint upon another can be obviated by the form of the structure. This is called determining the line of pressure. Upon these two lines the equilibrium of the structure depends. The lines of pressure and resistance in the arch of a bridge are calculated so as to pass into the abutments or piers, where they take a new direction; the strength of the abutments or piers, and the amount and direction of the strain upon them, being calculated by the architect so as to render them capable of permanently supporting the fabric. When the pressure upon an arch causes it to give way, it

breaks into four parts, the stones turning inward upon their superior edge at the crown, and outward on their inferior edge at two points in the haunches where the line of resistance reaches the interior edge, and which are called the points of rupture. The ancients, being unacquainted with the full theory of the arch, usually made their arches more numerous, of smaller span, and with stronger piers than are found necessary in modern structures. Another advantage which the modern architect of bridges has over the ancient is in the invention of the cofferdam (q.v.). This is a water-tight case made to protect the middle piers of a bridge, by driving piles down to the solid foundation, and filling them up with clay or other impermeable material, so as effectually to exclude the water. In constructing a bridge it is desirable to have the smallest possible number of points of support. Piers in the water-way are not only expensive to form, but obstruct the navigation of the river. When the water-way is obstructed the bridge itself is exposed to danger, the wearing action of the water sometimes undermining the piers on which it rests. The pier, at the point where it supports the arch, is usually oblong in form, and increases in breadth to the foundation. The rate of increase in modern bridges is frequently three inches to the foot. The ends of piers are provided with salient angles to act as cut-waters; the form of these differs according to circumstances. In building the arch of a bridge, a timber framework is used called a "centre," or "centreing." The centreing keeps the voussoirs in position till they are keyed in; that is, fixed by the completion of the central part; its construction is a matter demanding the utmost care of the architect. On removing this framework, which is called "striking the centre," what is called the settlement of the arch takes place, the central voussoirs move slightly downward, while a corresponding rise takes place in the flanks. Before striking the centre of the bridge of Nogent-sur-Seine, Perronet caused three lines to be cut, one horizontally over the crown, and two obliquely from the extremities of this line to the springings. On the striking of the centre these lines were found to have altered their forms and relative positions. From straight lines they had become curves. The horizontal line had sunk, and its greatest deflection was above the key, while the oblique lines from the springings were deflected upward. The "spandrils" of a bridge are the spaces between the haunches of the arch and the point of junction of the extrados with the roadway. These are frequently filled up with rubble-work or gravel. They are sometimes left open to give greater lightness to the structure. The former plan has been generally adopted in the large French bridges; the latter was recommended by Telford. Owing to the superior skill of modern engineering, the roadways of bridges are made much wider and more level than formerly.

The most ancient stone bridge in England is said to be the Gothic three-way bridge at Croyland, or Crowland, in Lincolnshire, said to have been built in 860, though the present work is much later. It originally spanned three watercourses, and is so steep that none but footpassengers can go over it. The longest old bridge in England was that over the Trent at Burton, in Staffordshire, built in the 12th century, of squared freestone. It consisted