Similar products are also formed by heating gutta-percha which closely resembles caoutchouc in its chemical structure.
The hydrocarbon of gutta-percha yields similar results and is therefore closely related to caoutchouc.
Gutta-percha-covered copper wires were formerly largely used for the purpose of underground lines, the copper conductor weighing 40 lb per statute mile, and the gutta-percha covering 50 lb (90 lb total).
It thus possesses the same composition as the hydrocarbon of gutta-percha and as that of oil of turpentine and other terpenes which are the chief components of essential oils.
Forest products - gums and resins of various sorts, such as gutta-percha - are valuable articles of export.
Of two transatlantic cables laid in 1894, the core of one consisted of Soo lb copper and 320 lb gutta-percha per mile, and that of the other of 650 lb copper and 400 lb gutta-percha; whereas for the similarly situated cable laid in 1866 the figures were 300 lb copper and 400 lb gutta-percha.
Owing to the high price of gutta-percha the tendency, of recent years, has been to approximate more closely to the theoretical dimensions, x xvl.
The great advantage of this air insulation is that the electrostatic capacity of the wires is low (about one-third of that which would be obtained with gutta-percha insulation), which is of the utmost importance for high-speed working or for longdistance telephonic communication.
Species of Palaquium, the genus from which, in the Indian Archipelago, the best gutta-percha is obtained, occur on the hills, and from their cultivation there might in time be obtained a large revenue independently of European labour.
In 1859 he began, in concert with Sir William Thomson (afterwards Lord Kelvin), to work on problems respecting the making and use of cables, and the importance of his researches on the resistance of gutta-percha was at once recognized.