The Story of the Atlantic Telegraph

And now once more the work began. No time was to be lost. It was already the first of March, and but four months remained to manufacture sixteen hundred and sixty nautical miles of cable, and to prepare for sea. But the obstacles once cleared away, all sprang to their work with new hope and vigor. In the cable to be made for the new line, there was but little change from that of the last year, which had proved nearly perfect. Experience, however, was constantly suggesting some improvement; and while the general form and size were retained, a slight change in the outer covering was found to make the cable both lighter and stronger. The iron wires were galvanized, which secured them perfectly from rust or corrosion by salt water. Thus protected, they could dispense with the preservative mixture of the former year. This left the cable much cleaner and whiter. Instead of its black coat, it had the fresh, bright appearance of new rope. It had another advantage. As the tarry coating was sticky, slight fragments of wire might adhere to it, and do injury, a danger to which the new cable was not exposed. At the same time, galvanizing the wires gave them greater ductility, so that in the case of a heavy strain the cable would stretch longer without breaking. By this alteration it was rendered more than four hundred-weight lighter per mile, and would bear a strain of nearly half a ton more than the one laid the year before.