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Gutta-percha is a genus of tropical trees found naturally in Southeast Asia and in many South Pacific islands. More importantly, for pur- poses of this posting, the term is also applied to the sap of these trees. The sap is an inelastic natural latex, some- what similar to the sap of the rubber tree. The trees themselves can grow to be over 100 feet in height and up to nine feet in circumference. The leaves are a glossy evergreen, between five and ten inches in length. The tree produces berries up to two inch- es in diameter. The sap is biological- ly inert, water resistant, resilient to pressure, and (most significantly) a good electrical insulator. Unlike unvulcanized rubber (so-called India rubber), gutta-percha does not become brittle over time. Shortly after the invention of the electrical telegraph in 1837, it became apparent that laying a submarine communica- tions cable between Europe and the United States could be both highly beneficial and highly profitable. Various experiments were conducted. One of the major problems was keep- ing seawater out of the cable. Tests soon revealed that gutta-percha was an excellent coating for the cable, as it was flexible, electrically insulating, and largely impervious to seawater. For the next hundred years, up until the chemical revolutions following World War II, gutta-percha was the product of choice for submarine cables globally. Its bio-inertness has also made gutta-percha useful in vari- ous medical applications. It is still used in dentistry to fill the empty space inside the root of a tooth fol- lowing root canal procedures. Utilizing its thermoplastic character- istics, companies for many years made decorative and functional objects (such as chess pieces, tea trays, and plaques) out of gutta-percha. It was also used for the core of golf balls and for hand grips on revolvers and pistols. The submarine cable industry, though, owes its tremendous success to the viscous juice of an obscure tropical tree. (Posted on MaritimeProfessional.com by Dennis Bryant) www.seadiscovery.com Marine Technology Reporter 7 Gutta-percha A Big Factor in the Early Sub Cable Industry
