first brown, then quite black, presenting the appearance which we see it has in articles of commerce. The sap of the tree is laid on a mould in successive layers, which are allowed to dry, and are formed into bottles and cakes, in which form it is exported. The natives of South America are very ingenious in the uses to which they apply it. Boots, shoes, syringes, and tubes, are among the many articles of domestic use into which it is converted. The tubes they use as torches, which burn very clearly, and emit but little odor. According to the celebrated chemist, Faraday, its composition is carbon, 87.2, hydrogen, 12.8—a hydro-carbon. It melts when exposed to a heat of 248°, and is resolved into vapor at 600°, and can be condensed into a liquid called caoutchoucin. In 1770, a cubic inch of India-rubber was sold in London for seventy-five cents, to erase pencil marks. It was not used to make water-proof fabrics until about the year 1800. These were first invented by Charles Mackintosh, of Glasgow, who applied a naptha solution to the surface of two pieces of cloth, then laid them together, passed them between rollers and thus cemented them together. [Illustration: NATIVES GATHERING GUTTA-PERCHA.] A “Mackintosh” was the name applied for many years to a water-proof coat. Dr. Ure, although well aware of Mr. Mackintosh’s invention, coldly passes it over in his dictionary. It is supposed that personal feeling was the cause of this, as Dr. Thomson and Ure were once rival chemists in Glasgow, and Mackintosh was the friend and pupil of the former. The fabrics of Mackintosh had a most disagreeable smell, still he was the first person who established India-rubber manufactures in Britain, and perhaps the world. He afterwards removed his factory to Manchester, England. Various kinds of goods made of India-rubber soon afterwards began to be manufactured in England, but they were all decidedly objectionable to use, until the grand discovery of sulphurization was made; for this the world is indebted to an American inventor, Nathaniel Hayward of Woburn, Mass. This substance, or rather, compounds of it, is now manufactured into so many articles of beauty and usefulness, that it forms an object of no small wonder to witness the rapidity with which such manufactures have sprung into existence.