SCOTCH, their neglect of ribbed arches, 94. SEGÓVIA, the Roman Aqueduct, visited by Marshal Ney, 183-4; its technique, 189. SEMIRAMIS, her reputed bridge over the Euphrates at Babylon, 273-4. SENTIMENTALISTS, BRITISH, 33 _et seq._, 294, 360-1. SEWERS, Roman, 161. SEX IN BRIDGES, 194, 284-5, 293-4. SEXTUS IV and the Ponte Sisto, 197, 265. SHAKESPEARE, his debt to the Mediæval Church, 233. SHAPUR I of Persia, 202. SHIH-CHUAN, in Western China, its important bridge, 247. SHOREHAM BRIDGE, OLD, in Sussex, 41-3. SHREWSBURY, WELSH BRIDGE AT, used to be a fortified work, 261. SHRINES, WAYSIDE, 207, 230, 236, 246-7. SHRINED BRIDGE at Elche in Spain, picture facing page 236; at Trier over the Moselle, 247. SHUSHTER, in Persia, the Pul-i-Kaisar, 202-4. SICHUAN, China, bridges in this province, 126, 145, 210 _footnote_, 248, 315, 347. SIGHS, BRIDGE OF, 307. SIN-DIN-FU, now called Ching-tu-fu, this city’s bridges as seen by Marco Polo, 210 _footnote_. SISTO, PONTE, 197, 265. SLAB-BRIDGES with Stone Piers, 125-8; see also 61-3, 100-5. SLEEP is united by bad dreams to the law of battle, vii. SMEATON, JOHN, English civil engineer, _b._ 1724--_d._ 1792, his big “scientific” bridge over the Tyne at Hexham was a tragic failure, 339. SMILES, SAMUEL, Scottish author and pontist, 104. SMITH, SIR WILLIAM, English classical scholar, the Pons Sublicius, 140; the Porta dell’ Arco at Arpino, 157; the stones employed in the Pont du Gard, 171 _footnote_; the masonry of the Pont du Gard, 175 _footnote_; Roman aqueducts, 189 _footnote_; the Pons Salarus, 191; Pons Cestius, 196; Pons Neronianus, 197. SMYRNA, Roman Bridge and Aqueduct, 164. SOMMIÈRES, on the Vidourle, Roman bridge at, 179. SOSPEL, GATEWAY BRIDGE AT, 276. SOUTHWARK BRIDGE, London, its queer history, 326-7, 357. SPAIN AND HER BRIDGES, 13, 27-9, 104-5, 179-88, 238, 285-9. SPANS, WIDE, IN STONE BRIDGES, the Puente de San Martin, Toledo, 140 feet, 288; at Trezzo, 251 feet, 309; Grosvenor Bridge, Chester, 200 feet, 309; Trajan’s Bridge over the Tagus, 309 New London Bridge, and Waterloo Bridge, 309-10; Pont de Gignac and Pont de Lavaur, 160 feet each, 310; Bridge of Cho-Gan, China, 313-14. SPEED-WORSHIP, and its effects on the strife that bridges and roads circulate, 48. SPIDERS gave lessons to primitive men in the building of suspension bridges, 145. SPIERS, R. PHENÉ, architect and writer on architecture, 190, 199. SPRINGERS, the voussoirs at the springing of an arch. SPRINGING OF AN ARCH, the plane of demarcation between the ring and the abutment is called the springing. In other words, the springing marks the place where a ring of voussoirs starts out on its upward curve from a pier or from an abutment.