GliTTA PERCIIA, or Gutta Man. The Malay name for the concrete juice of a large forest tree : one of the Sapotete—a native of Borneo, Malacca, and the neighboring countries. It is chiefly brought from Singapore: it was used by the natives as a substitute for horn and wood, to make handles for knives and choppers. The juice is obtained by cut ting down the tree, and allowing the juice to exude from the cut end. This is a most wasteful proceeding, as the number of trees must shortly be so limited as to destroy the supply of the article. Mr. Brooke, of Borneo, says the tree is often six feet in diameter at Sara wak, and is believed to be plentiful all over Borneo, and probably at the thou sand islands that cluster to the south of the Straits of Singapore. Its frequency is proved by the circumstance that seve ral hundred tons of the Gutta Percha have been annually exported from Singa pore since 1842, when the substance first came into notice. There is reason, how ever, to fear that the supply must shortly decrease, and the price be raised, from the wasteful mode in which the natives collect it, often sacrificing a noble tree, of from fifty to one hundred years growth, for the sake of twenty or thirty pounds of gum, which is the largest quantity any one trunk ever affords. • The juice might, in all likelihood, be obtained from the _Pemba, as from other trees, by tap ping, and thus procuring a smaller por tion for several successive years ; but this process is too slow for the Malayans, and is also less likely to be adopted be cause the forests are common property. The people fell the tree, strip off its bark, and collect its milky juice in a trough formed of the hollow stein of the plantain leaf, when, being exposed to the air, it soon coagulates.
As it comes to market, it is a dirty white, pinkish, solid, opaque, having but little smell, and insoluble in water; it has a silky, fibrous texture, especially when drawn out. It feels smooth and greasy between the fingers. Below 50° it is hard, tough, and partially flexible, when thin like horn ; between 50° and 70°, it is elastic, and more flexible, yet still tough and stiff , between 140° and 160°, it becomes quite soft and plastic, and loses its tenacity. In this state pieces of it may be joined, all that is ne cessary being to press them together, when they form a perfect joint. By cut ting it up in fragments, and boiling in i hot water, most of the impurities may be removed. When thus purified by cooling, it passes into a solid mass ; when softened by either hot water or simple dry heat, it may be molded into any shape, or pressed into a pattern : as it cools, it gradually recovers its tough ness ar;c1. rigidity. In consequence of this it forms perfect casts of coins, me dals, &c., which, if carefully made, have all the sharpness of sulphur without its brittleness. When hot, it. is easily cut with the knife or saw, but when cold it is difficult to eat it, without wetting the tool with cold water. It is lighter than water, and floats on it : the spec. gravity being when pure •9791. In its chemical relations it cloudy resembles caoutchouc, and is isomeric with it : it differs, how ever, in some physical properties. By destructive distillation it yields similar products, affording a clear limpid oil of a mixed composition between 360° and 390°. It is insoluble in alcohol and water, dissolves partially in 'oil of tur pentine, ether, and perfectly in cold naphtha, benzole, sulphuret of carbon, and caoutehicine. Of these the benzole is the fittest ; when dissolved in it by the aid' of gentle heat, and then poured out on a glass plate to evaporate the benzde, the gutty percha is left behind in the form of a white film or skin. In this way very thin sheets of this sub stance is obtained. SOuberain has made an ultimate analysis of it, which yielded to him carbon 87.8, hydrogen 12.2. Mr. Crane believes the crude article to be composed Of two substances : 1st, the pure white grata; and 2d, a brown color ing material. Benzoic separates them.
Dr. Montgomerie suggests, among the less immediately obvious uses to which gutta percha is applicable, that of mak ing raised type for the blind, and em bossed maps for the same unfortunate beings ; it takes a clear, sharp impres sion, and is also tough and durable ; he thinks it would likewise be found ser viceable in stopping decayed teeth.
G. Hancock, Esq., has taken out a pa tent for improving the manufacture of gutta percha. He suggests several me
thods of purifying the substance, which generally comes here much mixed with extraneous matter. It may be dissolved by heat and strained, or passed through a screw press or inched by the addition of rectified oil of turpentine; and, after filtering through flannel or felt, the sol vent may be evaporated. In every case the gutty percha should form a residuum of the consistency of dough or putty— this plastic state being gained by the maintenance of a suitable temperature during the above process.
Mr. Hancock would combine gutta percha with caoutchouc, and a substance called gintawan (we have no clue to what this gmtawan may be), in order to form an elastic material impervious to water ; varying the proportions according to the greater or less degree of hardness or elasticity required for making elastic bands—a compound is used where 50 parts of gutta percha are combined with 24 of gintawan, 20 of caoutchonc, and 6 of orpiment. From a mixture of these, Mr. Hancock also prepares a light, po rous, and spongy material, suited for stuffing or forming the scats of chairs, cushions, mattresses, saddles, &e. ; like wise, springs of clocks, clasps, belts, garters, and strings. Wherever the re quisite is flexibility and elasticity, then the of gutta percha should be diminished, and increased where firm ness is wanted. By prolonging the pro cess much hardness may be acquired, and moulds and bails of gutta percha will bear turning in the lathe, like wood or ivory. The material is also applica ble to useful and ornamental purposes, as picture frames, door handles, walking 'Sticks, chessmen, handles of swords, and knives, buttons, combs, flutes, &c., &c. By the admixture of sulphuric acid, or of a tenth or larger part of vegetable wax or tallow, any degree of solubility, pli ancy, and softness, may be acquired; or the composition may be used as varnish to cover other materials, concealing any odor, and imparting a surface impervious to water. In printing silks and cottons it is useful, as it amalgamates readily with colors. The applications of gutta percha are endless : it makes good tubes for conveying water or gases ; speaking tubes, and hose ; drinking vessels, pitch ers, and other domestic articles. An extensive use is as soles for shoes, which are fastened to the clean and rasped leather sole by a fluid varnish made of the gutta dissolved in coal tar. A solution of it forms a good varnish for wires or cordage, or any substance which it may be desirable to protect or insulate. It is sulphurized occasionally, and some times combined with caoutchouc. At the American Gutta Percha Company, having their factory in Brooklyn, N. Y., the various modifications and articles of which this substance is susceptible of being applied to, is interestingly demon strated., Gutta percha is of the most powerful negative electrics, and may be used for insulating positive surfaces, or for de veloping quantities in place of the glass cylinder. A thin sheet of this substance wrapped round' a bottle or wooden cylin der, and turned by hand, gives a copious supply of the fluid for experiment.
Previous to 1844, the very name of gutta percha was unknown to European commerce. In that year two cwt. of it was shipped, experimentally, from Sing apore. In the first four and a half years of the trade, 21,598 piculs of gutta perchs valued at $274,190, were shipped al, Singapore, the whole of which were sent to England, with the exception of 15 piculs to Mauritius, 470 to the Continent of Europe, and 922 to the United States. But this rapid growth of the new trade conveys only a faint idea of the commo tion it created among the native inhabi tants of the Indian Archipelago. The jungles of Johore.were the scenes of the earliest gatherings, and they were soon ransacked, in every direction, by parties of Malays and Chinese, while the indi genous population gave themselves up to the search with a unanimity and zeal only to be equalled by that which made railway jobbers of every man, woman, and child in England, about the same time. The knowledge of the article stir ring the avidity of gatherers, gradually spread from Singapore northward as far as Penang, southward along the east coast of Sumatra to Java, eastward to Borneo, where it was found at Brune, Sarawak and Pontianak on the west coast at Keti, and Passe on the east.