Gutta-percha is now turned by surgeons to various uses, chiefly for splints and covering moist applications to retard evaporation. A splint of gutta-percha is made by taking a rigid board of the substance cut to the desired shape, soaking it in hot water, and then bandaging it to the limb. In a few minutes the gutta-percha is found hard, and modeled to the shape of the parts. Gutta-percha being readily soluble in chloroform, such a solution is sometimes used for covering raw surfaces, as when the chloro form evaporates it leaves a pellicle of solid gutta percha. It is also used in dentistry. It softens in warm water, and can be molded into any form in that state, as soft it is not sticky, and turns well out of molds. It will always be of great value as a material in which to take casts, as it can in the soft state he made to take the sharpest forms most faithfully; and as it quickly becomes hard, and preserves its shape, if not too thin, the range of its utility in this respect is very extensive. Golf-balls are made of gutta-percha.
Gutta-percha is supple, flexible, and very tena cious and extensible, so that it may be drawn out to many times its length and retain almost all the extension. It is insoluble in water and dilute acids; it resists alkalies and hydrofluoric acid, so that the latter may be contained in bottles or other receptacles made of or coated with gutta-percha. Gutta-percha is used for making a vast variety of ornamental and useful articles; but its most important application is for the insulating coating of submarine conduc tors. In this application, as in most others, its chief defect arises from the readiness with which it becomes oxidized and decomposed. Its great
value arises from the ease with which it can be worked, and its being so complete a non-con ductor of electricity. Its non-conducting power is not modified by burying it in the ground or plunging it in fresh or salt water. Gutta-percha is used as an insulating material in nearly 200, 000 miles of ocean cables, and it is its suc cessful application to this purpose that has made the extensive development of submarine teleg raphy possible. From the time when Morse laid his telegraph line in New York Harbor from Castle Garden to Governor's Island, in 1842, using an insulated copper cable, the promoters of sub marine telegraphy were seeking for a suitable insulating material. During this time Mont gomerie was independently studying the proper ties of gutta-percha, and it was suggested by Wheatstone, who was unable to put the idea into practice, that it would be a suitable insulating covering for a submarine conductor. This was successfully accomplished about 1848.
Attempts have been made to remedy the defect of gutta-percha of softening in a high tempera ture by a process of vulcanization similar to that so successfully applied to india-rubber (q.v.), but the results have not been satisfactory.
Gutta-percha differs very materially from caoutchouc or india-rubber in being nonelastic, or elastic only in a very small degree. Not withstanding this very striking character of caoutchouc, the two articles are often confounded in the public probably from the similarity of their applications. India-rubber is displacing gutta-percha in some of its most important appli cations, and especially in the coating of both land and marine telegraph cables. See TELEGRAPH,