682 POPULAR SCIENCE MONTHLY. 



investigationri. Some confusion prevailing in regard to tlie ex- 

 pression " India rubber," what follows may justify the English 

 name of the substance : In 1765 Aublet announced his discovery 

 of the tree in French Guiana. In 1773 Magellan, descendant 

 of the great navigator {Le Caoaiichouc et la GuUa-Percha, E. 

 Chapel), proposed caoutchouc, or " resine elastique de Cayenne," 

 as a substitute for bread crumb in erasing pencil marks. It was 

 known in France as ^^eaw de negre. In England, where the dis- 

 covery was attributed to the celebrated Priestley, who only propa- 

 gated a foreign idea, designers soon came to call the article " In- 

 dian rubber." It was not known as a product of Asia until 1798. 

 Hence the thought of the time probably connected it with its 

 South American habitat and thus with its Indian gatherers. The 

 appearance of the little cube in the shops about 1775 was the be- 

 ginning of the great part now played by India rubber in the arts, 

 sciences, and industry. In 1780 Berniard, a Frenchman, experi- 

 mented in a line with Hdrissant and Macquer, and found oil of 

 turpentine to be the best solvent. He also succeeded in impart- 

 ing various colors to the gum. 



By 1791 syringes, sounds, bougies (1779), and elastic bands had 

 been made of caoutchouc. The manufacture of impermeable tis- 

 sues had been tried in France in 1791 by Besson. The idea was 

 borrowed from the Indians, from whom the early Spaniards had 

 learned to gum their hempen cloaks, which when thus treated 

 were impervious to rain, but degenerated in the sun. Hancock and 

 Mackintosh, in England, were the first to make waterproof gar- 

 ments, later than 1818, the rubber cloth being used as lining (E. 

 Chapel). Hancock devised important processes for treating rub- 

 ber, and in 1838 invented ink erasers ; but it remained for Mack- 

 intosh alone, by employing benzene as a solvent, to produce, in 

 1823, the first successful garments, which at once came into great 

 favor, in spite of their disagreeable odor. At present, three 

 tissues are made: "simple tissues" (having one rubber face), 

 "double-faced tissues" (rubber on both sides), and "double tis- 

 sues " (two stuffs with one rubber coating between). " Mackin- 

 tosh " is " double tissue," and the method of manufacturing it is 

 substantially the same as at first, only machinery is used. In the 

 calender machine the fabric is spread with rubber solution, is 

 drawn by a roller under a scraper to remove excess, and passes 

 upon a steam table, where the solvent evaporates, leaving a thin 

 pellicle of rubber on the stuff, which thoroughly dries in passing 

 around a drum and is wound upon a mandrel. It may then be 

 taken to the front of the machine and the process repeated. Ten 

 coats are sometimes applied. The product must afterward be 

 vulcanized, to render it less sensitive to heat and cold. 



Many do not understand how much we owe to vulcanization 



