This bridge, which was composed of 18 arches, was begun in 1176, and completed in 1183. In 1385, dur ing the contentions of the popes, some of its arches were destroyed; three others fell in 1602, from the ne glect of repairing a fallen arch. In 1670, the frost was ao great, that the Rhone for several weeks bore the hea lest carriages: when the thaw followed, the ice de stroyed the piers; but the third pier, with the chapel of St Nicholas, has stood notwithstanding all these acci dents.
Our admirable bridge saint, not the least useful of that once numerous class of enthusiasts, in accomplish ing, under such circumstances, so difficult, valuable, and magnificent a work as the bridge of Avignon, has perhaps quite as just a claim to the power of perform ing miracles as most of the saints of his day ; and it is not improbable, that from the influence of his tomb, and that of his mantle upon the surviving breth ren, that the still greater briel;es of Lyons of 20 arches, and St Esprit of 19, were accomplished. Parts of the elevation of those bridges are given in Plate LXXXIII.
Perronet states, that in 1.;54 an arch of 150 French feet, or 160 English feet span, was built at Verona ; and in 1454, one of 172 French feet, or 183.8 English span, and 66 French feet, or 70.6 English of rise from the springing, at Vielle-Brioude upon the river Allier in France. The last mentioned is the greatest span we know of for a stone arch, In Italy there are many fine bridges. The peculiar situation of Venice has required a number far beyond what is to be found in any other city. The finest is the Rialto of 984 feet span, and 23 feet rise. It was designed by the celebrated Michael Angelo, and erect ed between 1588 and 1591. Gautier states, that the numbers in the different.quarters of the city are as fol lows, viz.
In France, during the two last centuries, many fine. bridges have been erected. The Pont Royal over the Seine at Paris, in 1685, from a design of Mansard. It consists of five arches. The centre one 77 French, or 82.3 English feet span; the breadth, including parapets, 56 French, or 59.9 English feet. The bridge at Blois, built from a design of the Sieur Gabriel, consists of 11 arches; the centre one S6 French, or 91.10 English feet span; the breadth over the parapets, 50 French, or 53.5 English feet.
Perronet gives plans and descriptions of sundry large bridges in France, constructed between the years 1750 and 1772.
The first in point of time and magnitude is the new bridge upon the Loire, at Orleans The ancient bridge, which consisted of 19 arches, was in so bad a state, that it was found necessary to construct anew one; for which a design, made by M. Hupeau, then first engineer of bridges, was preferred ; and by that time such as the progress made in bridge building, that, instead of 19.
arches, as in the old edifice, this new design consisted of only nine. The middle arch is 100•French, or 106.9. English feet span, and the rise or versed sine 28 French, or 29.11 English feet. The arches next the abutments are 92 French, or 98.3 English feet span, and rise 25 French, or 26.8 English feet: the others are in propor tion, The breadth, including the parapets, 46 French, or 49.2 English feet. It was begun in 1750, and open ed to the public in 1760. Nothing can exceed the simplicity and elegance of this bridge, as will appear by the elevation, one half of which is given in Plate LXXXIV.
Of the same beautiful simplicity of character is the design of the bridge upon the river Seine, at Mantes. It consists of three arches: the middle arch is 120 feet French, or 123.2 English feet span, and rise 36 French, or 38 5 English feet ; the two side arches are 108 French, or 115.4 English feet span, and rise 32 feet 6 inches French, or 34.9 English ; the breadth, including the parapets, is 33 French, or 35.3 English feet. It was also designed by M. Hupeau; begun under his direc tion in 1757; and during that and 1758, raised to the level of the sixth course of arch stones: the work was then suspended on account of a war. It was recom menced in 1763 under the direction of Perronet.
Hupeau having died in that interval,) and was opened in 1765 One of the finest of the French bridges, and the greatest work of Perronet, is that upon the Seine a Neuilly. It consists of five arches, each 120 French, or 128.2 English feet span, and 30 French, or 32 Eng lish feet rise; the breadth including the parapets, is 45 French, or 48 English feet. It was begun in April 1768, and opened in October 1773; the masonry was completed in 1774 ; the roads, and other operations con nected with this bridge, were finished in 1780. A great peculiarity in this bridge, well deserving the at tention of engineers employed in similar works, is, that the soffits of the arches are shaped to suit the contract ed vein of water, as formed in the entrance and exit of pipes. This is accomplished, by making the general form of the body of the arch elliptical, with a rise of 30 French, or 32 English feet, or of the span; but mak ing the headers follow the segment of a circle, the versed sine of which is only 131 French, or 14.5 Eng lish feet, or about of the span. This, besides afford ing facility for the passage of flood waters, gives a great appearance of lightness to the whole fabric. The ef fect will be seen in the elevation, one half of which is given in Plate LXXXIV.