However after successful joining of an additional length

However after successful joining of an additional length, the task was completed on the November 13,1851. It was the first truly successful undersea cable, continuing in business for the next 24 years. The very considerable size of this achievement can be appreciated by looking at the hydrostatic pressure undersea cables may have to endure -- up to 4t/in2, at a depth of three miles. Moreover, the cable will move with the current, more violently in shallow water and close to a shoreline. In tropical oceans, there is also the problem of the teredo worm, one of the lamellibranch family of boring molluscs, whose destructive vigour proved as deadly to submarine cables as it had previously done to ships' timbers, wharves and sea dykes. Atlantic crossing In May 1853 another narrow waterway was conquered by cable; that between mainland Britain and Ireland. Earlier attempts had been made to bridge St George's Channel but had failed, largely because of the treacherous currents and deeper water. The Magnetic Company under chief engineer Charles Bright laid a six-wire cable between Donaghadee in