Engineering Wonders of the World
Volume I

THE BRIDGES OF THE MENAI STRAITS. 151 ends. The steam-engines perched on the towers began to force water at enormous pressure into the cylinders of the presses ; Rinsing the rams emerged slowly, the „ . As the tube ascended, the Tube. masonry was built in under- neath it, so that there should never be a clear space of more than a few inches under the iron- work. Robert Stephenson had insisted before- hand that, though the strength of the beams supporting the presses, and of the chains, was sufficient to bear the load, no risks were to be taken. A Serious Disaster averted. The ends of the tube were lifted alternately, and they rose gradually to a height of about 30 feet. Then occurred an accident which proved only too conclusively how justifiable was Stephen- Without the least warning, son’s caution. one of the hydraulic presses burst, and the tube fell 7 inches on to the packings which had been built up underneath it. So small a fall may appear to the uninitiated to be of slight consequence ; but the momentum ac- quired by the 900 tons of iron grew, even in that small distance, to such proportions as to crumple up solid castings, weighing tons, as if they had been mere biscuit boxes. “ Thank God,” wrote Mr. Clark, the engineer in charge, to Stephenson, “ that you have been so obsti- nate ; for if this accident had occurred with no bed for the end of the tube to fall on, it would have now been lying across the bottom of the straits.” As it was, this accident strained the tube, though fortunately not to a serious ex- tent, and added an item of £5,000 to the cost —£234,450—of building the bridge. A new cylinder having been provided, the tube was raised to its final position ; and in due course its three gigantic brothers, each of which, if stood on end in St. Paul’s Church- THE BRITANNIA BRIDGE AS IT IS TO-DAY. VIEW FROM ANGLESEY SIDE. (Photo, London and North-Western Railway Company.)