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THE VEGETABLE IVORY TREE.
are whiter than ivory, and as hard if they are not put under water; and if they are, they become white and hard again when dried. Bears devour the young fruit with avidity. The part of the kernel which is thus similar to ivory is of the same nature, though not of the same consistence, as the flour of corn, the spicy substance of the nutmeg, and the meat of the coco-nut, which in other palm trees becomes very hard; that of the date palm becomes quite as hard, if not harder, but it is not white enough or large enough to be worth using by the turner. The doum palm, or forking palm of Thebes, the fruit of which is called gingerbread nuts at Alexandria, has a similar albumen, which is turned into beads for rosaries. A model of the double coco-nut, or coco de mer, has been made, beautifully carved from its own nut, as hard as ivory, and susceptible of a fine polish. A figure has also been made, forming the shaft of a lady's parasol, which is not to be distinguished from ivory.
THE CAOUTCHOUC TREE.
INDIA RUBBER TREE.
The India rubber tree, from which Caoutchouc is chiefly obtained, is a native of South America and India. It has shining, pointed, oval leaves, small uneatable fruits the size of an olive, and long pink buds. It grows to the size of an English sycamore. It is chiefly found on the declivities of mountains, amongst decomposed rocks and vegetable matter. It produces when wounded a great abundance of milk, which yields about one-third of its weight of Caoutchouc. It grows with great rapidity; a tree is described as being twenty-five feet high, with the trunk a foot in diameter, when only four years old. The juice of this valuable plant is used by the natives of Silket to smear over the insides of baskets, con
structed of split rattan, which are thus rendered water-tight. Old trees yield a richer juice than young ones. The milk is extracted by incisions made across the bark, down to the wood, at a distance of about a foot from each other all round the trunk, or branch, up to the top of the tree, and the higher the more abundant the fluid is said to lie. After one operation the tree requires a fortnight's rest, when it may again be repeated. When the juice is exposed to the air, it separates spontaneously into a firm elastic substance, and a fætid whey-coloured liquid. Fifty ounces of pure milky juice taken from the trees in August yielded exactly fifteen ounces and a half of clean washed Caoutchouc. This substance is of the finest quality, and may be obtained in large quantities. The Ficus elastica may be often seen in hot-houses in this country.
The use of Caoutchouc with which we are most familiar is that of removing the marks of leadpencil from paper, and its most common name is India rubber. It is not much more than a century since it was introduced into Europe, and the manner of its production was at first unknown. In 1735 some members of the French Academy of Sciences visited South America, when they found it was the thickened juice of a Brazilian