Page:The American Cyclopædia (1879) Volume III.djvu/745

CAOUTCHOUC 735 relished both by natives and European resi- dents. The flowers have a five-cleft calyx ; a pitcher-shaped hairy corolla, with five short, erect teeth ; five stamens, rising from the base FIG. 2. Urceola elantlca. of the corolla, and having very short filaments and arrowhead-shaped anthers. The castilloa elastica, the Mexican tree, grows from 50 to 100 ft. high and from 8 to 20 in. in diameter. It has male and female flowers alternating on the same branch. The male flowers have sev- eral stamens inserted into a hemispherical perianth, consisting of several united scales. The female flowers consist of numerous ovaries in a similar cup. The South American tree, the siphonia elastica, varies from 25 to upward FIG. 9 Siphonia elastica. of 100 ft. in height. The leaves consist of three entire leaflets radiating from the top of a long stalk, and are clustered toward the ends of the branches. The flowers are borne in loosely branched panicles, with numerous little branchlets consisting of a few male flowers and a female at the top. Both sexes have a bell- 150 VOL. in. 17 shaped five-toothed calyx, and no corolla. The fruit is a large capsule composed of three one- seeded pieces, which split in leaves when ripe. The raw seeds are poisonous to man and quad- rupeds, but macaws eat them, and they are used as a bait for fish. Long boiling deprives them of their poison. The province of Para, south of the equator, in Brazil, furnishes to commerce immense quantities of caoutchouc. The tree is tapped in the morning, and during the day a gill of fluid is received in a clay cup placed at each incision in the trunk. This when full is turned into a jar, and is ready at once to be poured over any pattern of clay, or a wooden last covered with clay, the form of which it takes as successive layers are thus ap- plied. Its drying and hardening are hasten- ed by exposure to the smoke and heat of a fire, and thus the substance acquires its ordinary black color. Dried by the sun alone, it is white within and yellowish brown without; when pure, it is nearly colorless. Complete drying requires several days' exposure to the sun; during this time the substance is soft enough to receive impressions from a stick, and is thus ornamented with various designs. The natives collect it upon balls of clay in the forms of bottles and various fanciful figures, in which shapes it is often exported. They also make it into tubes, which they use for torches. The clay mould over which the bottles are formed, being broken up, is extracted through the open neck. From the custom among the natives of presenting their guests with one of these bot- tles furnished with a hollow stem, to be used as a syringe after meals for squirting water into the mouth, the Portuguese gave the name of seringat, or syringe, to the gum and also to the tree which produces it. The moulded ar- ticles are brought into Para suspended on poles to keep them from touching each other, as for a long time they continue sticky. It is not only prepared in various moulded forms, as bottles, toys representing animals, rudely shaped shoes, and in flat cakes also for exportation, but a method has been devised for preserving the juice as it comes from the tree, and shipping this in air-tight vessels of tin or glass. The liquor is first filtered and mixed and well sha- ken with about -^ of its weight of strong am- monia. On being poured out upon any smooth surface, and exposed to a temperature of 70 to 100 F., the ammonia, which preserved it from the action of the oxygen of the atmosphere, evaporates, and leaves the gum in the form of the object which holds it. It has in this state a pure white appearance. The juice is of a pale yellow, of the thickness of cream, of a sourish odor, and of specific gravity 1'012. The pure caoutchouc which separates from it, rising like coagulated albumen to the surface, as the mixture of the juice with water is heat- ed, has the specific gravity of only 0-925. This, being skimmed off like cream as it forms, is found to constitute about 32 per cent, of the juice. It may also be precipitated by salt or