GIRDERS, there are three types or classes of bridge: the girder, the arched, and the suspended. Girders may be of various materials; wrought iron, cast iron, and wood are chiefly used. Professor Fleeming Jenkin describes with apt brevity the essential difference between the three classes of bridge. “In all forms of the suspension bridge the supporting structure is _extended_ by the stress due to the load; in all forms of the arch the supporting structure (i.e. the ring of voussoirs) is _compressed_ by the stress due to the load; and in all forms of the beam or girder the material is partly extended and partly compressed by the flexure which it undergoes as it bends under the load. Thus when a beam of wood carrying a load bends, the upper side of the beam is thereby shortened and the fibres compressed, while the lower side of the beam is lengthened and the fibres extended.” So, too, in a girder of metal. In some bridges, as in the High Level Bridge at Newcastle, the girder principle is united to bowstring arches of metal, but a true girder is less expensive and lighter, 80. GIZEH, AT, in the Great Pyramid of Menkaura, there is a very early pointed arch, 155-6. GLACIERS, in their relation to rock-basins and rock-bridges, 152. GLANVILLE, GILBERT DE, Bishop of Rochester, 1185-1215, built a small chapel at the Strood end of Rochester Bridge, 245. GLASTONBURY, its lake-village a good example of prehistoric bridge-building, 21, 137 _et seq._ GOTHIC ARCHITECTURE, her genius described, 152-3. GRANDISON, Bishop of Exeter, granted indulgences to those who helped in the building of Bideford Bridge, Devon, 305 _footnote_; See also “Indulgences.” GRATIANUS, PONS, another name for the Pons Cestius, 196. GRAY, WALTER DE, Archbishop of York, between 1215 and 1256, rebuilt the Ouse Bridge, preserving some portions of the Norman Chapel, 242. HADRIAN, destroyed Trajan’s Bridge over the Danube, 129; and built the Pons Ælius at Rome, 194. HALL, LADY JANE, in 1566, contributed a hundred pounds to repair the Ouse Bridge at York, 242. HAMBURG MERCHANTS, THE YORK SOCIETY OF, after the Reformation, used the chapel on the Ouse Bridge as an exchange, 242. HAND-GUNS, 333. HANDICRAFT, the first public school, 118; has never had a standard of uniform merit, 121; its indebtedness to Nature’s models, 3, 4, 6, and Chapter II. HAND-MADE WEAPONS preceded hand-made bridges, probably, 110. HAROLD’S BRIDGE at Waltham Abbey, 162. HAUNCHES OF A BRIDGE, 265 _footnote_. HENRI IV, PONT, at Châtellerault, 331-2; see also the illustration facing page 332. HENRY III, of England, and his wife, rob Old London Bridge of her revenues, 49-51. HENRY V, of England, in the fourth year of his reign Abingdon Bridge was built, 251.