The old Hungerford Bridge stood here previously, and its two piers of brickwork were used for the new bridge. Other piers are huge cylinders of cast iron ten feet across, but fourteen feet in diameter in the ground. Thus they are broadly based. These piers are filled with concrete and also brickwork, and are topped with bearing-blocks of granite. They are formed of plates of cast iron bolted together, and they were sunk into the ground many feet below high-water by combined forces; divers scooped out the mud and gravel and clay from within the cylinders; water was pumped out and heavy weights pressed them down. The piers became fixed on the London clay, but when filled were heavily weighted to drive them down again, and finally they were forced to a depth of over sixty-two feet below high-water mark. But before lattice girder bridges had become so popular, another class had come into use, and afford some splendid specimens of engineering skill. These are suspension bridges, and, perhaps of all kinds, they are the most picturesque. Their graceful sweeps and curves yield perhaps a more pleasing sight for the eye than the solid, rigid, straight lines of the girder bridges. It was the genius of Thomas Telford which gave a great impetus to this class of bridge. Like Stephenson after him, he had to bridge the surging Menai Straits, but for a carriage road, not a line of rails; and at length, after various plans had been suggested and abandoned, he proposed the Suspension Bridge. Now, in its simplest form, a suspension bridge has been known for ages. It is merely a pathway, or even a small movable car, suspended from a rope or ropes across a chasm. Ulloa describes suspension bridges built by the Peruvians in South America. Four stout cables span a river, and on these four is placed the platform of sticks and branches, while two other ropes connected with the platform are useful as hand rails. Such bridges sway with the wind and move with the passenger, but for light loads they appear to be perfectly safe. In Telford’s Menai Bridge the carriage-way is hung from four huge chains or cables, each chain made up of four others, and passing over high piers. The chains are anchored on the landward side, sixty feet in pits, and grafted by iron frames to the rocks. The chains are so complex and so strong, that parts may be removed for repair without imperilling the safety of the structure. The length of the span thus gained is 560 feet, and it is 150 feet above high-water. The remainder of the bridge is composed of arches of stone, of 52½ feet span. The piers from which the great span is suspended rise above the carriage-way fifty-two feet, and are topped by blocks of cast-iron, which can move on rollers to permit the chains passing over them to expand and contract freely with the temperature. There are two carriage-roads, and also a footpath. The roads are separated by iron lattice work, which also gives them stability and decreases vibration.