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BRIDGE 271 century ; it had 36 arches of squared freestone, and was 1,545 ft. in length. The first stone bridge over the Thames, known as the old Lon- don bridge, was commenced in 1176 by Pe- Fio. 2. Old London Bridge in 1616. ter of Colechnrch, who is supposed to have be- longed to the Brethren of the Bridge ; Peter died before the completion of his work, and was buried in the crypt of the chapel erected on the centre pier; this was in accordance with a custom of the society, that when any member died during the superintendence of an important work, his remains should be en- tombed within the structure; the work was completed in 1209, during the reign of King John, and was chiefly remarkable for its mas- siveness, and enormous surplus of material, having 20 arches in a span of 940 ft., with piers varying in solidity from 25 to 34 ft., so that two thirds of the stream was occupied by the piers, and at low water a still greater pro- portion, leaving at that time less than one fourth of the whole span for waterway, and causing a most dangerous fall. The bridge of the Holy Trinity at Florence, over the Arno, was built in 1569 ; it has a total length of 322 ft., is composed of three elliptical arches, and stands unrivalled as a work of art ; the mate- rial used in its construction is white marble. The Rialto at Venice, designed by Michel An- gelo, and erected in 1588-'91, has a single span of 98J ft., with 23 ft. rise. The total number of bridges in that city was estimated by Gautier at 340. The bridge of Pont-y-Prydd, over the Fio. 8. Bridge of Pont-y-Prydd. Taff in Wales, is considered one of the most extraordinary in Britain; it was built in 1755, by an uneducated mason named Edwards, after the failure of two structures which he had 121 VOL. in. 18 previously erected at the same spot ; the first was carried away by a freshet after standing two and a half years, and the second failed in consequence of the weight on the haunches forcing out the keystone before the parapet was finished ; the present structure consists of a single circular arch, with a span of 140 ft. and a rise of 35 ft. The bridge of Mantes, over the Seine, was erected by Perronet and Hus- seau in 1765, and consists of three elliptical arches, the centre one having a chord of 128 Fio. 4. Bridge of Neullly. ft. The famous bridge of Neuilly was con- structed by Perronet in 1774; its total length is 766 ft., with a clear waterway of 639 ft. ; there are five arches of equal width, the curves being false ellipses, with chords of 128 ft. and versed sines of 32 ft. The bridge of St. Maix- ence, over the Oise, was also built by Perronet between 1774 and 1785; it is chiefly remarka- ble for the flatness of its arches, the chords be- ing 76 ft. 8 in., while the versed sines are only 6 ft. 3 in., and the thickness of the voussoirsat the vertex of the arch 4 ft. 8 in. Waterloo bridge, over the Thames in London, built by Rennie in 1811-'17, is 1,240 ft. in length, and com- posed of nine elliptical granite arches, each of 120 ft. span, and a versed sine of 32 ft. ; the piers are fronted with coupled Doric columns, producing an elaborate effect; another pecu- liarity is that the roadway is level, differing in this respect from the other bridges across the Thames. Westminster bridge, completed in 1750, by Labelye, is remarkable as inaugurating a new era in bridge architecture ; the novelty consisted in the manner of laying the founda- tions, which was effected by means of caissons, the depth of water and rapidity of the current rendering the expense of coffer-damming un- Fio. 5. New London Bridge. desirably great ; the bridge is 1 ,220 ft. in length, and has in all 15 semicircular arches, two of which, however, are quite small. The new London bridge is an imposing structure of granite, and was completed by Rennie in 1831 ; it has a total length of 928 ft., with five elliptical arches, the span of the centre arch being 152 ft., and its versed sine 29 ft. 6 in. In the Uni- ted States there are comparatively few stone bridges of great size. Perhaps the finest ex- ample we have is the High bridge of the Cro-