monly imported, a ball of clay is fixed on the extremity of a stick, and repeatedly dipped into the extracted fluid. Each coating requires a short time to dry and harden, by exposure to the air or to the sun; and several such coatings produce the requisite thickness; after which the stick is withdrawn, and the clay is broken and washed out: others are formed wholly on clay. On opening some of these bottles, the remains of clay, and also the shape of the stick, may be observed in them. Their general size is from two to eight inches in diameter; their outside surfaces are either left plain, or indented, before they are perfectly indurated, with various figures, which afterwards remain indelible. They are also equally capable of receiving any kind of raised or embossed work, by the addition of small pieces of the gum to their surfaces, whilst in the same state. These bottles and all hollow figures of animals, fruit, &c. are thus molded or formed on models of clay, excepting the smaller parts of them, which are made by coating short pieces of twine or other substances with the fluid. gum, and adding them to the figure before its surface is perfectly indurated.

The thick blocks of caoutchouc are made in moulds of clay; and sometimes merely by digging trenches or holes in the ground near the trees, and causing the extracted gum to flow into them, wherein it gradually indurates: and commonly so little care is taken during the process, that pieces of clay, with dry sticks, grass, and leaves, are sometimes found in the midst of their substance; and also small cavities partly filled with the juice in a fermented state; others are nearly free from these imperfections. They are generally from one to three feet long; and about two inches thick; having much of the appearance of cork. For the purpose of erasing the strokes of blacklead pencils or crayons, small pieces of these blocks are preferable to the bottles or to any other shape, being more durable and convenient. A new block on being cut appears white internally, and the more so toward the centre; but this original white colour will not remain on its surface, where it is in immediate contact with the air, longer than a few days; yet, after the dark shade has penetrated about an eighth of an inch deep, it requires a much longer time to penetrate farther.

Of the Syringe tree, Siphonia cahuchu, or Siphonia elastica, an account is obtained from the observations of M. de la Borde; who, when travelling by the order of the French government through the interior of Africa, A. D. 1772, found several of them growing on the banks of the lakes and rivers. Those in the woods are not readily observed, from their tufted branches being much intermixed with the surrounding foliage; but they may be distinguished by the number of young plants produced by their falling seeds, and springing up beneath them: these, being overshadowed by the forests, are mostly prevented from growing to maturity. The resinous juice flows at all times of the year; but the rainy season is the most favourable for collecting it; and the natives generally prefer this time for the purpose. They begin the operation by washing the stem of the tree to the height of seven or eight feet, to free it from moss, &c. and perhaps to make the gum flow more readily. A cord is then bound round the trunk at the height of about one foot from the ground, to support a trench or gutter, which is made of clay with a short spout projecting off at one side of it; under which is placed a calabash shell, or a hollow shaped piece of clay, to receive the gum. Several deep gashes are then cut through the bark, to the height of five or six feet; and the white juice exuding therefrom, flows around the trench, and runs down from the spout to the receiving vessel; into which the clay-models, of any requisite shape, are afterwards dipped repeatedly, until their surfaces have acquired by induration a sufficient thickness, or number of coatings. After the process is finished, the substance remains extremely flexible, and nearly insoluble: warm water, or a moderate heat, softens it, and makes it more pliable, but never renders it capable of being remoulded.

The Syringe tree is also a native of South America: in Brazil it grows to the height of fifty or sixty feet; generally straight and free from branches, excepting at the top, where they are numerous and much divided; its leaves are green on the superior surface, and white beneath, growing three together on the same leaf stalk; the seeds are contained in pods, each consisting of three cells, resembling those of the Ricinus or Palma Christi. Amongst others, M. Aublet has noticed its

fruit, and the white and resinous juice produced from its trunk; and a botanical description of its flowers has been given by M. Richard, a French botanist. In the forests to the north of Quito, where it is found in great abundance, the inhabitants have given it the name of Heve. From incisions purposely made in the bark, there exudes a white fluid resembling milk, which gradually hardens in the air: of this they make torches or flambeaux; and in the province of Quito, they render a kind of coarse cloth water proof, by covering it with a thin coat of the fluid caoutchouc, which soon indurates thereon; and it thus answers the common purposes of oil-case. On the banks of the Amazon river, the natives form the gum into rude figures of birds, fruit, and toys of different kinds, which are not easily broken. For making them they employ clay models: these are covered with one layer or coating of the gum, and exposed to the smoke of a fire until its white colour changes to a deep yellow: the same operation is repeated until it is brought to a proper thickness. When that is done, and it is become sufficiently indurated, the models are crushed by pressing together the sides of the hollow figure, and afterwards washed out. In this manner they form elastic bottles, and also shoes and boots, which in texture and colour much resemble those made of leather, and they possess the additional advantage of being impervious to water.

The nation of Omaguas, situated in the interior of South America, also form the caoutchouc into bottles, to the necks of which they fasten a hollow reed, and thus convert them into a sort of syringe. From this circumstance the Portuguese of the colony of Para, have called the tree Pao de Xiringa; and hence the name of Seringat has been given to it, and also to its resinous production. The wood of this tree has been wrought into small masts, it being both light and straight. There are other trees in South America producing a white juice, which may be converted into similar articles with those made from the common caoutchouc or syringe tree; although the quantity of juice, produced from them, and also its quality, may be various. M. Fresneau observes, that the elastic gum produced in the colony of Cayenne, indurates very quickly after it exudes from the tree, so that it can be formed into the No. 23.

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requisite shapes only at the places where it is produced; that it is applied to a great variety of uses, and is applicable to many more; and therefore may become of considerable value to the colony by converting it into regularly saleable articles.

From the preceding abstracts, it is clearly evinced that the substance of caoutchouc is elastic, flexible, impervious to air and water, and of a fibrous texture, not easily separated or destroyed; yet, in its natural fluid state, capable of being spread on cloth, paper, cordage, &c. or of being moulded or modelled on clay or wax into any requisite shape; and is easily obtained in the most abundant quantities in the various places from whence it is commonly imported.

These qualities and circumstances combined, and thus practically obtained, are all that are required in the proposed method of constructing elastic Beds and Pillows, Portable Tentbeds. Seamen's Hammocks, water-proof Life-preservers, &c. comprising flexible and impermeable cases, occasionally enclosed in external cases of the usual construction and appearance, and capable of being filled with atmospheric air, instead of down or feathers, for the purpose of being rendered more or less elastic; and also for obtaining an equal and natural temperature, and other obvious advantages of lightness and portability, buoyancy, &c. resulting from the foregoing method of construction. From the preceding abstracts it is also apparently evinced, that such a manufactory can be established with advantage only at the places where the fluid caoutchouc is produced immediately from the trees, unless some eligible method can be found either to import it in this natural fluid state, or otherwise to dissolve the indurated caoutchouc without destroying its essential qualities.

In addition to the present purpose, the impermeable cerecloth, which has been made of various materials coated with this vegetable substance, may be advantageously applied to the numerous purposes of leather and of flexible oil-case. It may be made of any size and shape, without seams of thread, and either elastic or not, according to the nature of the cloth or other material which is made the basis of the work. It may be employed for covering chests, trunks, portmanteaus, &c. and more particularly the roofs of coaches. A thicker and

stronger sort may be made into thongs, straps, and traces, carriage harness, saddles, reins, and bridles: these would have the usual appearance of leather, and possess all the utility of it, with the advantage of the more durable properties of caoutchouc, either with or without its elasticity, as may be required; and they may be made entire, without seams of thread in any part: for, if two or more pieces of indurated caoutchouc, which are required to be brought in contact with each other, are pressed together, having some of the same substance in its natural fluid state previously applied to their surfaces, they will soon become equally inseparable with any other part of the work, as the fluid readily indurates between them; and, by means of additional external coatings, every appearance of the line of contact may be effectually closed. This is exemplified in the construction of some of the artificial figures of caoutchouc which are commonly imported. And, by the same means, combined with those before mentioned, various instruments, either wholly or in part, may also be constructed, particularly for hydrostatic and hydraulic purposes: as flexible tubes, of various diameters, for conveying air or water; the flexible parts of bellows of every description; some kinds of chemical and surgical instruments. Also water-proof shoes and boots; aprons and entire dresses for workmen employed in chemical laboratories, &c. And hereby considerable improvement may be made in the construction of valves and concave packings, for the pistons of hydraulic presses, forcing pumps, and condensers; also in the construction of machines of aërostation; for the entire coating of which, with all their appendages, caoutchouc may be advantageously employed, from its superior strength in proportion to its weight, and from its durable, impermeable, and elastic properties. Different sorts of twines and ropes have been coated with it to various degrees of thickness, whereby they have been strengthened, and rendered considerably more durable; and therefore ships' cordage may be more permanently preserved from decay, if thus coated with a firm, dry, flexible, and impermeable substance, than by means of any of the resinous productions which are commonly employed. And, on further investigation, it will be evinced that caoutchouc, in its natural fluid state, is not only