CAOUTCHOUC 691 



To accomplish this object the loom must bo peculiarly constructed ; its warp and 

 work beams must stand at an oblique angle with the sides of the loom, and the batten 

 and slay must bo hung in a peculiar manner, in order to beat up the weft or shoot, in 

 lines ranging diagonally with the warp. 



Canvas painted of various patterns is used for covering halls, &c., and is gene- 

 rally called floor-cloth. A finer kind of canvas, properly prepared, is employed by 

 artists. 



CAOUTCHOUC, GUM-ELASTIC, or INDIA-RUBBER (Caoutchouc, Fr. ; 

 Kautschuk, Fcdcrharz, Ger.) occurs as a milky juice in several plants, such as the Sipho- 

 nia Cahuca, called also Hevea Guianensis, Cautschiw, Jatropha elastica, Castilleia das- 

 tica, Cecropia pdleta, Ficus religiosa and indica, Urceola elastica, &c. Dr. Lindley's 

 account of the plants that yield the most important supplies of commercial caoutchouc, 

 with plates of the leaves and flowers, will be found in Mr. Hancock's work on Caout- 

 chouc. These are stated to be Siphonia elastica, Hancornia speciosa, Ficus elastica, 

 and Urceola elastica. It is, however, extracted chiefly from the first plant, which 

 grows in South America and Java. The tree has incisions made into it through the 

 bark in many places, and it discharges the milky juice, which is spread upon clay 

 moulds, and dried in the sun, or with the smoke of a fire, which blackens it. Portions 

 of this milky juice have been occasionally sent to Europe in bottles; some few arrived 

 with the milky emulsion, but generally they were found to be resolved into a coagulum 

 floating in an aqueous solution. A small bottle from Cayenne or the Isle of France, 

 in the possession of M. D'Arcet, passed some years without change, but the severe 

 winter of 1788-9 caused it to pass to the solid state, and the bottle was broken. 



Sir Joseph Banks is reported to have had a bottle of liquid unaltered, but which 

 afterwards was decomposed. Fifty gold louis-d'ors, it is said, were offered by him at 

 Lisbon in vain for a second supply. 



Caoutchouc, Gum-Elastic, or India-Eubber, are the general names for a substance 

 now so well known, familiar, and important, that it seems matter for surprise that the 

 latter half of the preceding century should have passed away before it was made 

 known to Europe by memoirs read to a learned body. For the remainder of the cen- 

 tury, its extraordinary property of elasticity, and the grotesque objects made by the 

 Indians, caused it to be met with in the cabinets of the curious ; its use was still con- 

 fined to erasing marks of black-lead pencil from paper, and in this country it received 

 the common name of lead-eater. 



Europe is indebted to the observations of M. de la Condamine, who, despatched from 

 France on a scientific mission, found the natives and residents of that part of South 

 America which he visited constantly using syringes, bottles for non-corrosive liquids, 

 boots, and many other articles, made of India-rubber. In 1736, he wrote to the 

 Academy of Sciences at Paris an account of this substance ; which during his tea years' 

 residence in Para, and journeys in the country, and along the banks of the Amazon, he 

 had constant observation of the use of by the natives. 



He describes the forms of bottles and articles moulded with clay, coated with the 

 milky juice of trees, in successive layers, and when dried in the sun, the earth broken 

 out, and says that the Indians, with a point of hard wood, impressed ornaments upon 

 the soft mass. 



He also states that the gum-resin spread upon cloth formed a waterproof 

 covering of great use for bagging to keep biscuits, food, and clothing dry from rain, 

 and as a substitute for tarpaulins ; and he especially notes the use of a great canvas 

 prepared with liquid India-rubber, to cover the quadrant circle as it stood on its legs, 

 which allowed it to be left in the rain and snow, and thus enabled them to make 

 observations at intervals of weather, and avoid the great labour of removing the 

 instruments to boxes and places of shelter. To obviate the adhesion of objects 

 recently made to each other, especially if the sun is upon them, 'Spanish white, and 

 even dust is employed : ' the inconvenience is thus prevented, and the articles imme- 

 diately take the brown colour which is ultimately acquired by the exposure of the 

 white juice to the sun and air, smoke and fire, methods employed by the Indians. 



M. de la Condamine found in the province of Esmeraldes this substance, called by the 

 natives HheV6 ; it is obtained by a single incision from the plants, and is a white 

 liquid like milk, which hardens and blackens in the air. The Indians made flam- 

 beaux 1 inch thick and 2 feet long, that burnt very well without a wick for 24 hours 

 with a brilliant flame and without any disagreeable odour. This caoutchouc was 

 wrapped in two leaves of bananier to form the flambeaux ; he used these lights habit- 

 ually, on his route along the river Esmeraldes, and especially in the wood of Sylanche, 

 where he was detained for days. 



It was in 1751, that M. dela Condamine brought the subject into notice, for M. Fres- 

 noau had found and described trees in Cayenne, yielding elastic resin. Writing to his 



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