6

OF CYLINDRICAL VAULTS.

Cassius, inasmuch as the size may render his accountquestionable.

The ancient bridge * * * § of Brioude , over the river Allier , in the department of the Upper Loire, of onearch, exceeds any vault of ancient or modern con-struction in the length of its chord.

The great arch f of the Ponte del Castel Vecchio,over the Adige at Verona , built in the year 1354;that of Gignac, over the Herault , finished in 1793 byM. Garipuy; that of Claix, erected 1611 over theDrac, on which was inscribed “ Romanos moles pu-dore suffundo ■” that of Lavaur, upon the Agout,erected 1775 ; and that of Vizile, over the Romanche ,erected by M. Bouchet, are much celebrated.

The arch of the Rialto, erected by Giovanni daPonte, 1588, generally attributed to Michael Angelo,and t the middle arch of Blackfriars, are exceeded bythe elliptical arch § erected by the Scotch mason overthe Liffy near Dublin , by that at Warwick erected bythe Warwick mason, by that of the Yorkshire oneat Winston, and by that erected for the late Duke ofDevonshire at Lismore in Ireland ; but still more

* The chord of the bridge of Brioude over the river Allier is183 feet. See Perronet, p. 335. Brioude is a corruption of theindigenous name for bridge. Montfaucon says the chord is 208feet.

f The chords of the arches of the Ponte del Castel Vecchio, ofGignac, and Lavaur, are 160 feet, of Claix 159, of Vizile 137.

t The chord of the arch of the bridge of the Rialto at Venice is96 feet; and that of the middle arch of Blackfriars’ Bridge,London , is 100 feet.

§ The transverse diameter of the bridge over the Liffy, nearDublin , is 106 feet, and the semi-conjugate only 22 feet. Thechord of the arch of the bridge at Warwick is 104 feet; at Win-ston 108 feet; of Lismore 100 feet.