The ship could now handle three gigantic reels of wire, each over 1,000 miles long. And they could feed off the back of the ship. The size and weight of the ship helped solve the problems of rough seas or bad weather. And its ability to turn tightly was a godsend when soundings indicated obstructions below.
Only the Great Eastern could have carried the largest roll of wire made to that point (2,700 miles). In July of 1866, the Great Eastern successfully ran a cable across the Atlantic. One previous cable had worked only sporadically for two weeks before it failed.
This new cable was manufactured by Telcon, an amazingly modern name for a Victorian company. Its cable design was lighter and stronger than previous cables and consisted of seven strands of copper under three layers of gutta percha and one layer of hemp. The entire construction was covered with 18 strands of iron wire.
Not only that, but the Great Eastern then turned around and found a broken cable from a previous attempt, 680 miles from shore, and completed that. In the space of a few weeks, Cyrus Fields (1819-1892) and the Anglo-American Telegraph Company had two operating cables.
The new chief engineer, Professor William Thomson (1824-1907), later named Lord Kelvin, had a brilliant idea, e.g. publicity stunt. He assembled engineers, scientists and reporters in the transmission building on the Irish coast and sent a message to the Newfoundland station asking them to attach the two cables at their end. This gave him a 3,200-mile cable that began and ended in the same room.
He then made a simple battery, using a silver ladies thimble, a steel pin and a few drops of lemon juice. With his key and this battery, he sent a clearly discernible message down 3,200 miles of cable to the astonished multitude. This was also made possible by his invention of the "mirror galvanometer," which could move a light beam on a wall with the most microscopic change in current on the cable.
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