434] C AO Various conjectures have been formed by the most eminent bo- tanists, and chemists, as to the means used for inspissating and in- durating this vegetable substance. The general opinion, however, is, that it concretes gradually when exposed to the air. It is particu- larly celebrated for the uncommon flexibility and elasticity, which it di plays immediately on acquiring a solid consistence, and for the many purposes to which it is ap- plied by the Indians, who make boots of it that are impenetrable to water, and when smoked, have the appearance of real leather. They also make bottles of it, to the necks of which reeds are affixed, and through these the liquor is squirted by pressure. The inhabitants of Quito, in Peru, also prepare from this substance a specif s of oil-cloth and canvas, which are formed by moulds made of clay, and worked Into a variety of figures. Over these moulds is spread the juice ob- tained bv incision ; and, as often as one layer is dry, another is added, till the vessel acquires a proper thickness ; when the whole is held over a strong smoke of burning vegetables, which gives it the tex- ture and appearance of leather. Before the operation is completely finished, the substance, whhe still soft, will admit of any impression being made on its surface, which is indi - The chemical properties, and other interesting peculiarities of elastic resin, have been dili- '.v explored b ; . r the most inge- nious natural philosophers of Eu- rope, from the time it was first n. Various experiments have . made to dissolve it, and to ascertain whether it would assume
- .-at figures, with the same
CAP facility as it did in its original stnte". This has been effected by the fol- lowing simple process : Mr. Winch put a pound of good vitriolic aether into a bottle, capable of containing four pounds of any common fluid. On this aether he poured two pounds of pure water, stopped the bottle, inverted it, and agitated both li- quids for several minutes, in order to mix, or, rather, to wash the aether in the water. On subsiding, as the aether floated on the top, he left the bottle in the inverted di- rection, opened it cautiously, sub- stituted his thumb for the stopper, and thus let the water gradually escape into a vessel beneath. This operation he performed re-» peatedly, till the sixteen ounces of aether were reduced to five. Hav- ing thus obtained a very pure aether, he found it to be the most perfect solvent of elastic gum. When im- mersed into it, after being cut into small pieces, it began to swell in a very short time; and, though die aether acted on it but slowly at first, yet, in five or six hours, the whole was completed)' dissolved, and the liquor remained transparent. It too large a proportion of elastic gum be employed, it will subside to the bottom; and may, after be- ing taken out of the bottle, be moulded into any form, so as to retain its former elasticity. The caoutchouc is at present chiefly employed by surgeons, for the injection of liquids, and also by painters, and odiers, for rubbing out pencd marks, kc. ; though we do not hesitate to say, that it may be advantageously used for sochs, or even shoes and boots, as well as various useful articles of domestic convenience. CAPER, or CappariS) L. an ex- otic genus of plants comprising se- ven
