The superintendence and care of bridges was always an important object with the Romans ; it was at first committed to the priests, who thence obtained the name of puntifices ; afterwards it was given to the censors and curators of roads; and at last the emperors took it into their own hands. In the middle ages, the building of bridges was esteemed to be an act of religion ; and about the close of the twelfth century, St. 13enezet founded a regular order of hospitallers, under the denomination of pontifices, or bridge-builders, whose pro wince it was to erect bridges, appoint ferries, and entertain tra vellers in hospitals built on the banks of rivers.
)f the bridges of antiquity, that built by Trajan across the Danube, near the town of Warhol, in Hungary, is allowed to have been the most magnificent. It was destroyed by Adrian, hut some of the piers may still be seen.
The remains of a bridge bearing as strong marks of ruined magnificence as any of antiquity, are to be met with at the bottom of a hill, on which the town of Narni is seated, on the road between Loretto and Rome. This bridge was built by Augustus, to join two mountains, between which flows the river Nera, and to enable the inhabitants of Narni to pass on a level from one mountain to the other. It was of an extra ordinary height, and its whole length, S50 palms (6311 feet). It consisted of four large unequal arches.
The next considerable Roman work of this kind is the Pont du Garde, about three leagues from Nismes ; which serves the double purpose of a bridge over the Gardon, and an aqueduct for supplying the people of Nismes with water. The bridge, which consists of six arches, is about 465 feet in length, and supports a second series of 11 arches, which are continued beyond the extremities of the bridge, and form a junction with the slope of the mountains on either side ; it is about 780 feet long. Over these is a third series of 35 arches, much smaller than those below, S50 feet in length, support ing a canal on a level with the two mountains, along which the water is conveyed to Nismes by a continued aqueduct. This extraordinary edifice is built with very large stones, held together by iron cramps without cement. The whole height is 190 feet above the lower river.
The bridge of St. Esprit, near Lyons, is of Roman origin, and has long been deemed one of the finest and boldest of the ancient bridges of France. Its whole length is upwards of
600 yards ; it is very crooked, bends in several places, and makes many unequal angles, particularly in those parts where the river has the strongest current. The arches run from 15 to 20 fathoms in width. The feet or bottoms of the piers consist, in their lower parts, of several courses of footings jutting out like steps ; and are each protected by two pedes tals, projecting from them. Between the large arches are smaller apertures, like windows, reaching nearly to the tops of the pedestals, about the middle of the pier. This mode of construction was adopted with a view to break gradually the mighty force of the Rhone : the several courses of steps, jutting out from the piers, oppose and break the stream by portions, and prevent it from operating with its whole force upon the fabric at once ; and when the flood rises so high as to cover the steps and pedestals, the small arches, or windows, allow the water to pass freely, which otherwise would have choked in the upper part of the great arches, and endangered by their being forced up.
The city of Valenza de Alcantara, in Spain, is celebrated for its ancient bridge over the Tajo, or Tagus, about 25 miles from Madrid, built in the time of the Emperor Trajan ; and, as appears from an inscription over one of its arches, by the people of Lusitania, who were assessed to defray the expense. It is 200 feet above the water, and though consisting of only six arches, is 670 feet in length, and 23 in breadth. At the entrance of the bridge is a small chapel dug in the rock by the pagans, who dedicated it to Trajan ; but when the Chris tians obtained possession, they consecrated it to St. Julian.
Near the old town of Brioude, in the Lower Auvergne, or department of the Upper Loire, is a stupendous stone bridge, of one arch, the largest with which we are acquainted. It is attributed to the Romans, and stretches over the whole stream of the Allier. The extremities of the arch rest on a natural rock, which occasions the spring on one side to be lower than on the other ; it is formed of squared stones in two ranks ; the rest of the fabric is of rubble-work. The span of the arch is 131 feet ; its greatest height, from the level of the water to its intrados, 68 feet 8 inches ; and the breadth of the bridge, 13 feet.