The Story of the Atlantic Telegraph

The machinery also was perfected in every part, to withstand the great strain which might be brought upon it in grappling and lifting the cable from the great depths of the Atlantic. This necessitated almost a reconstruction of the machinery, together with engines of greater power, applied both to the gear for hauling in forward and that for paying out aft. Thus, in case of a fault, the motion of the ship could be easily reversed, and the cable hauled back by the paying-out machinery, without waiting for the long and tedious process of bringing the cable round from the stern to the bow of the ship. But the most marvellous improvement had been in the method of testing the cable for the discovery of faults. In the last expedition, a grave omission had been in the long intervals during which the cable was left without a test of its insulation. Thus, from thirty to thirty-five minutes in each hour it was occupied with tests of minor importance, which would not indicate the existence of a fault, so that, if a fault occurred on ship-board, it might pass over the stern, and be miles away before it was discovered. But now a new and ingenious method was devised by Mr. Willoughby Smith, by which the cable will be tested every instant. The current will not cease to flow any more than the blood ceases to flow in human veins. The cord is vital in every part, and if touched at any point it reveals the wound as instinctively as the nerves of a living man flash to the brain a wound in any part of the human frame.