Gutta Percha

Advances in Technology Before telegraph cables could work under water, it was necessary to develop a cable with good waterproofing and electrical insulation. In the age before the development of man-made plastics, a material had to be found which would fulfil these requirements. Fortunately, Gutta Percha, a resin from the Isonandra Gutta tree was identified as a suitable insulating material.

Image: The foliage, flower and fruit of the Isonandra Gutta tree.

Section of submarine telegraph cable showing its component materials.The Gutta Percha is the dark section surrounding the central core

Locally made items of this material were brought to Europe from the Malay Peninsula and specimens were exhibited at the Royal Society of Arts in London in 1843. It was subsequently imported and used for various applications, including jewellery-making. In 1845. SW Silver & Co of Stratford, East London, invented a means of extruding it to cover wire.

Image: Collection of the 'juice' of the Isonandra Gutta tree.