BRIDGE. (Sax. brigge.) In Archi tecture, a structure for the purpose of connecting the opposite banks of a river, gorge, valley, &c. &c., by means of cer tain materials, forming a roadway from one side to the other. It may be of stone, . brick, iron, timber, suspended chains or ropes ; or the roadway may be formed by means of boats. Long previ ous to the introduction of bridges con structed upon geometrical principles, the modes of crossing rivers by throwing the trunks of trees across them, or by sus pension of ropes, or twisting together the branches of trees from bank to bank, were so obvious that they must have been resorted to at an early period. The former method., however, could only have been practised over narrow streams, whilst the latter might have been carried to almost any required extent. Mungo Park found this mode employed in Afri ca; and in South America rope bridgeS of bujuco, or thongs made from the hides of oxen, are in use at the present day. Don Antonio de Ulloa tells us, that over some of the rivers of Peru the bujneo bridges are of such dimensions that loaded mules in droves pass over them, and especially on the river Apurimac, forming the high road for the trade car ried on between Lima, Cuzco, and other places to the southward. Though such bridges are the contrivance of man in a less civilized state, they are the only means by which many streams whose currents are deep and rapid can be crossed; and the stupendous suspension bridges of the present day are but im provements on the simple scheme of the untutored architect of a savage period and people.
The use of the arch in bridging ap pears to have been first practically ap plied by the Romans. 'Ile Chinese, though using the arch, did not make it strong enough to bear wheel carriages. In Egypt and India it was unknown, or was not applied. There is no trace of the arch in the ancient works of Phenicia and Persia, and even the Greeks have a doubtful claim to it. Over the Tiber the ancient Romans built wooden bridges ; such was that which joined the Janicri lum to the Mona Aventinus, and was called the Pons Sublieius, from the word auhlicce (stakes) of which it was formed. Without enumerating the bridges of Rome, some of which are still standing to attest the science of their architects, we must mention the Pons Narniensis, on the Flaminian way, near Narni, and about sixty miles from Rome. It was built by Augustus, and vestiges of it re main to the present day, one arch above 150 feet span and 100 feet high being still entire. But of works of art, perhaps the most wonderful ever raised was the bridge built by Trajan over the Danube. It consisted of twenty piers, whose height from their foundation was 150 feet, and 170 feet apart ; its breadth being sixty feet. This stupendous work was demo lished by Hadrian, the successor of Tra jan, under the pretence that it might serve as a passage for the barbarians, if they became masters of it ; but some writers have said it was through envy of the fame that attached to its founder. Over the Tagus, in Spain, an ancient Roman bridge, near Alcantara, is still partly standing. It consisted of six arches of eighty feet span, extending al together 600 feet in length, and some of the arches 200 feet high above the water.
Of the temporary bridges of the Romans, the most famous was that of timber thrown by Ca;sar over the Rhine.
From the fall of the Roman Empire to the revival of the arts, the history of bridge architecture is, with the exception of the Moorish works in Spain, of no in terest. It appears from Gautier, who uses the authority of Mag. Agricola of Aix, that when the arts began to revive in Europe, an order was founded by St. Benezet, under the title of Brethren of the Bridge ; and that under them was begun, in 1176, the bridge at Avignon, consisting of eighteen arches and about 3000 feet in length. During the conten tions of the popes, in 1385, some of its arches were destroyed, and in 1602 three others fell. In 1670 the ice destroyed all but the third pier, which, with the Cha pel of St. Nicholas upon it, still remains. In 1354 a bridge of three arches was con structed at Verona, the roadway sloping from the city ; the largest of its arches, which are segmental, is 160 feet span ; but a still larger arch was built at Vielle Brioude in France, over the Allier, in 1454, of nearly 184 feet span, which is the largest stone arch upon record. Among the most celebrated bridges of Italy, is that of the Rialto at Venice, whose span is 981. feet. It was begun in 1588, and finished in 1591, from the designs of Antonio dal Ponte, though by most au thors absurdly attributed. to M. A. Buo narroti. In this city alone there are no less than 339 bridges ; but they are mostly of small spans. We must not omit in this place the bridge of Della Santissima Triniti, at Florence, by Am manati, which, as Milizia truly observes, has not been surpassed since the revival of architecture. It is of three arches, the middle one of 96 and the two side ones 86 feet span, the width of the piers being 26 feet 9 inches ; the breadth of the car riage and footways between the parapets is 33 feet. It has been usual for writers to call the form of the arches of this bridge cycloklal ; but from our own mea surements and most particular investiga tion, we can assert that they are not of that form. They are very slightly pointed, after the fashion of what is called. the Tu dor arch of this country ; the point at the summit, which is extremely obtuse, being hidden by the ram's head sculp tured on the key-steltes. During the two last centuries, the French have ad vanced their bridge architecture to very great perfection ; but more particularly in the latter part of the last century, in which appeared Perronet, the father of the modern system of the art, whose elegant designs have not since been im proved upon, either in France or in any other country. His is the beautiful bridge of Neuilly over the Seine. It con sists of five arches, each about 128 feet span and 32 feet rise : it was finished in 1774, and remains a splendid monument of the powers of its architect. Some of the more modern specimens of their bridges do great honor to the French school, in which beauty of form is united with sound engineering.