Page:Encyclopædia Britannica, Ninth Edition, v. 12.djvu/863

837 INDIA-RUBBER 837 In British Guiana rubber is obtained fromffeveapcntcifolia, Mull. Arg. ; in French Guiana from //. Guaycmensis, Attbl., where it is known as &quot; heve,&quot; &quot; siringa,&quot; or &quot; eahoutchou,&quot; the last being the probable origin of the name caoutchouc ; and in Venezuela from H. brasilicnsis, there called da pi or dapiche. None is exported to England from any of these localities. Small quantities of rubber intermediate in character between that of Para and Pernambuco are occasionally imported from Maranhao. On account of its great value as a source of caoutchouc, the cultivation of the Para rubber tree has been attempted in India; but it has been found to be too tropical a plant for cultivation in northern and central India, although suit able for Ceylon, Malabar, and South Burmah, according to recent reports. The seeds, which are about the size of a damson (fig. 2, d), soon lose their vitality, and cuttings do not thrive unless taken from the young wood. Ceara rubber is considered almost next to the Para in value, as it is a &quot;dry&quot; rubber, very elastic and free from stickiness; but it often contains a quantity of Avood and foreign matter aris ing from the mode of collecting it, the loss in washing pre vious to manufac ture amountingsome- times to 25 per cent. It is the produce of Manihot Glaziovii, Miill. Arg., a euph- orbiaceous tree com mon in the province of Rio Janeiro, about 30 feet high, with a rounded head of foli age, and greyish- green 3- to 7-lobed palmate leaves, some what resembling the leaves of the castor- oil plant in shape and size (figs. 3, 4, 5). The trees are tapped, according to Mr R. Cross, when the trunk attains a diameter of 4 to y? 10 - 9.Manifiot Glmiorii. (After II. Trimen, Journ. Bot.. Nov. 1880.) inches, ^.e., when they are about two years old. The mode of collecting the rubber is as follows. After brushing away the loose stones and dirt from the rootof the tree by means of a handful of twigs, the collector lays down large leaves for the milk to drop upon. He then slices off the outer layer of the bark to the height of 4 or 5 feet. The milk, which exudes in many tortuous courses, some of it ultimately falling on the ground, is allowed to remain on the tree for several days, until it becomes dry and solid, when it is pulled oft&quot; in strings, which are either rolled up into balls or put into bags in loose masses, in which form it enters commerce under the name of Ceara &quot; scrap.&quot; The amount of Ceara rubber imported in 1879 amounted to 500 cwt. The attempts which have been recently made to cultivate this rubber plant in India have been attended with signal success. In Rio Janeiro it grows in a rocky or stony arid region, where a short undcr- s.:rub is the only vegetation, and the atmosphere is hot and dry, the temperature ranging from 82 to 90 Fahr. It is, therefore, suited for cultivation where the Ilevcn will not grow. In Ceylon it has been found to thrive at an altitude of from 200 feet to 3000 feet above the sea level. At Zanzibar and Calcutta also it succeeds well. The seeds (fig. 5, c), which have a hard thick coat, take a year in germinating, unless the edges near the end bearing the car- uncular projection are rasped off. Cuttings, provided they have a single bud, strike readily. Pernambuco or Mantjabcira rubber is obtained from Hancornin tpeciosa, Gom., an apocynaceous tree common on the South American plateau in Brazil from Pernambuco to Rio Janeiro, at a height of 3000 to 5000 feet above the sea. It is about the size of an ordinary apple tree, with small leaves like the willow, and a drooping habit like a weeping birch, and has an edible fruit called &quot; mangaba,&quot; for which, rather than for the rubber, the tree is culti vated in some districts. Only a small quantity of this rubber comes to England, and it is not much valued, being a &quot;wet&quot; rubber. I.t occurs in &quot;biscuits&quot; or &quot;sheets.&quot; The caoutchouc is collected in the following manner. About eight oblique cuts are made all round the trunk, but only through the bark, and a tin cup is fastened at the bottom of each incision by means of a piece of soft clay. The cups when full are poured into a larger vessel, and solu tion of alum is added to coagulate the juice. In two or three minutes coagulation takes place, and the rubber is then exposed to the air on sticks, and allowed to drain for eight days. About thirty days afterwards it is sent to market. Pernambuco rubber, as is the case with most rubbers coagulated by saline solutions, contains a large quantity of water. FIG. 4 Manihof Olaziorii. Young leaf (half natural size) ; inflorescence (about half natural size); half-ripe capsule (real size). Cartagena rubber comes from New Granada in the form of black sheets | inch thick, having a somewhat rough or &quot; chewed &quot; appear ance, and is more or less &quot;tarry&quot; or sticky. It also occurs in the form of strips or small pieces pressed together in bags. Its Fin. n Manihot GJatiovii. a, mnle flower ; b, female flower ; c. seed ; d, section of seed. (All natural size.) botanical source is not known, but is thought to be a pinnate-leaved tree, a portion at least being derived, it is supposed, from Casttlloa flattica. It loses 35 per cent, of moisture when dried. The importa tion of Cartagena rubber into Great Britain has declined from 3518 cwts. in 1875 to 1679 cwts. in 1879. Guayaquil rubber is imported from Ecuador in large Hakes or lumps of a whitish colour in the best kinds, the inferior sorts being porous and filled with a foetid black liquid, having an odour of cow- dun&quot;, and staining the knife and hands. It is believed to be obtained from Castilloa elasfica. The amount imported into Britain has diminished from 3815 cwts. in 1875 to 482 cwts. in 1879. In washing for manufacture it sometimes loses up to 40 percent, oi its weight. The bulk of the two last-mentioned rubbei-s is ex ported to the United States. II. CKNTIIAT, AMERICAN. The source of all the principal rubbers exported from Central America is CasliUwi ehifttica, Cerv., a lofty