Engineering Wonders of the World
Volume I

144 ENGINEERING WONDERS OF THE WORLD. and give it the correct curvature the piers, he fastened together, end to end, a number of iron bars totalling five hundred and Experiment. geven^.y fee£ -n length. These were laid out in an adjacent valley, and raised at the ends until the centre was clear of the ground and the curve was the same as that a chain between water, the raft bearing the chain was taken in tow by four boats, swung moored across the straits on the line of the bridge. One end was end of the Carnarvon section, and leading over the top of the Anglesey pier to then made fast to a loose round, and Hoisting the Chains. to the other were attached strong ropes MENAI SUSPENSION BRIDGE FROM THE CARNARVON SIDE. (Photo, Valentine and Sons.) of the suspension chains to be. From the stresses recorded, Telford calculated that a pull of thirty-nine and a half tons would be needed to handle the central span of a chain. Each chain was divided into three parts— two to reach from the anchorages to the piers, the third to span the channel. One of the land sections—that on the Carnarvon side— was long enough to extend down the seaward side of this pier to water-level ; the other reached only to the pier saddle. The rest of the chain was built on a raft 450 feet long and 6 feet wide, ready to be floated to a position between the two piers. On April 14, 1825, the hoisting of the first of the chains took place under the eyes of thousands of people who gathered from far and near to witness the subjection of the straits. In the afternoon, shortly before high two capstans on the shore. At the given signal 150 sturdy labourers threw their weight on the capstan bars. Slowly the chain rose from the raft, and yet more slowly, as less and less weight was water-borne. Presently a great shout arose when the raft, now entirely freed from its load, floated down the tide. For another hour the ^he crowd watched the curve of the . made. chain grow flatter and flatter, and the word went round that a junction had been made with the Anglesey land section— in fact, that a continuous chain now extended from Anglesey to Wales. This provoked a fresh outburst of cheering, which in turn encouraged some foolhardy workmen to use the chain as an unlicensed bridge and win the perilous honour of being the first to cross the straits by an aerial pathway. Not that