It took more than money and man-power to lay the transatlantic cable. Gutta-percha, a natural plastic extracted from trees in Southeast Asia, sparked a craze in Victorian England, leading to its use in everything from golf balls to ear trumpets. But its greatest service may have been as the insulator that made the underwater cable possible.
A Natural Plastic
In 1843 a Portuguese engineer, Jose d'Almeida, described a natural plastic material to the Royal Asiatic Society in London. Gutta-percha, created by boiling the sap of the Malayan gutta tree, was similar to rubber but lacked rubber's elasticity. Malleable when heated, it hardened at room temperature but remained flexible. And although expensive (each tree yielded relatively little gutta percha), it had a wide variety of uses.
A few months after d'Almeida's speech, a surgeon working for the East India Company named William Montgomerie wrote an article about gutta-percha and sent some samples from Singapore to the Royal Society of Arts, where they were displayed. The samples touched off a gutta-percha craze. The novel substance was incorporated into everything from snuff-boxes to walking sticks, dolls to chess pieces. And the Gutta Percha Company, the main importer of the substance from Malaya, reaped the rewards.
The Ideal Insulator
In the same year that gutta-percha made its London debut, Samuel Morse put a wire coated in rubber inside a lead pipe and used it to send signals across New York harbor. Although rubber worked as an insulator for brief periods and short distances, it deteriorated with longer exposure to water. But scientist Michael Faraday discovered that gutta-percha did not suffer from this drawback. Soon the Brett brothers were using gutta-percha to coat the cable they strung across the English Channel, and when Cyrus Field went to London to find a manufacturer for his submarine cable, John Brett suggested that he use gutta-percha as well.
When Field's first cable was constructed, it had three layers of gutta-percha insulation wrapped around a core of seven strands of copper wire. In all, 300 tons of gutta-percha were used for the 2,500 nautical miles of this first cable, and even more for the second. Insulation for the first core weighed 261 pounds, but the second was protected by four layers of gutta-percha, as well as a substance called Chatterton's compound that was applied between the layers. As a result, the new core weighed 400 pounds per mile.
As an insulator, gutta-percha proved to be a great success. But it had a revolutionary impact on more than telegraph cables. In one of a great many applications, gutta-percha replaced leather filled with boiled goose feathers as the preferred material for golf balls. Later, when golfers discovered that after a few dents, the gutta-percha balls flew even further than before, dimples became a standard feature. Polyethylene would eventually replace gutta-percha in the insulation of underwater cables as well as most other uses, but the boiled sap of the gutta tree is still used by dentists to make temporary fillings.