154
HISTORY OF ENGINEERING.
Book I.
modern fortress. The views representing this bridge show the various alterations thathave been made in it. and will enable the reader to form some idea of its construction
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Pontus Salarius, Ponte Salaro , on the Tevcrone, is composed of three semicirculararches, 54 feet 6 inches to 69 feet span, and of two smaller arches, of 22 feet 4 inches span.It was built by Tarquinius Priscus 600 years, and restored by Justinian 570 years beforeChrist. The breadth is 29 feet: the stones which form the arches are large. It was nearthis bridge Manlius Torquatus took the collar of gold from the Gaul.
Ponte 1lotto or Senatorius, on the Tiber , was the first stone bridge erected in thecity ; another was built on its site, at the time Fulvius was censor, which was completedby Scipio Africanus , and lasted till 1364. It was entirely rebuilt, in the year 1575, byGregory XIII. , and was nearly destroyed twenty-three years after by a flood; at presentonly one arch remains, to exhibit its former magnificence: the piers are ornamented withlions’ heads holding a metal ring, and they have niches adorned by columns; the arch iscomposed of one row of voussoirs, of equal thickness, accompanied by an archivolt, themouldings of which follow the curve : it is also decorated with the sculpture of twomarine horses, admirably executed; the span of the arch is 80 feet, and the breadth 42 feet8 inches.
Seven bridges formerly conducted over the Tiber to the Janiculum and Vatican Mount:these were, the Pons Sublicius , afterwards called jEmilius, built, as its name implies, ofwood, and erected by Ancus Martins, according to Livy : this bridge stood between theAventine and the Ripa Grande, where the foundation of one of its abutments remains.Pons Pulatinus, or Senatorius, now Ponte Rotto ; the Pons Pabricius , now Ponte deQuattro Capi, from a therms with four faces placed on it; Pons Cestius, now Ponte diSan Bartolomeo ; Pons Janicularis, of which there are no remains, though the Ponte Sisto occupies its site. Pons Triumphalis, opposite the hospital of Spirito Santo, has a vestigeremaining, and here passed into the Campus Martius the victorious consuls to whom thesenate decreed triumphal honours, followed by their soldiers, captives, and spoils : afterentering the Porta Triumphalis, they passed the circus of Flora and Flaminius , thetheatres of Pompey and Marcellus, the portico of Octavia, and the Circus Maximus , tra-versed the Via Triumphalis, entered the Via Sacra, passed between the Coliseum andtemple of Venus and Rome, crossed the Roman Forum , and halted at the temple of Capi-tolinus.
The Pons jplius, or Ponte San Angelo, the ancient piers of which remain, was theseventh bridge over the Tiber, which, a few miles above Rome to the sea, is in width about300 feet on an average, therefore not difficult to span by a bridge. Its banks above andbelow the imperial city, once adorned by graves and gardens, in which were the villas otthe wealthier Romans, as well as the villages and palaces on its meandering banks, are nowonly traceable in their ruins. “ Deo gratissimus amnis,” the distinguished Tiber , has beenso woven into the recollections of the classic traveller, that it can never be forgotten.