684 POPULAR SCIENCE MONTHLY. 



method of treatment liave been made since Goodyear, who died 

 in 1860. 



The problem of regenerating vulcanized waste (old shoes, etc.) 

 has not yet been satisfactorily solved, no means having been found 

 to remove the sulphur completely, and to restore to the gum its 

 original properties ; yet there is an increasing tendency to use 

 partly reclaimed rubber and foreign mixtures. From 1881 to 1883 

 the waste followed the rise in the price of the gum, and this 

 led to the use of imitations made from linseed oil (first announced 

 about 1846), from arachis, and from colza oil, and they still con- 

 tinue to be considerably employed in the fabrication of cheap 

 articles. 



Pure India rubber is whitish. It is rarely used, the vulcanized 

 being preferred. Crude rubber is often mixed with pieces of bark, 

 stone, clay, etc. The lumps are softened in hot water, cut into 

 slices, generally by hand, and passed through washing rollers to 

 remove foreign substances. When dried, they are ready for mix- 

 ing with sulphur, etc., or for the "masticating machine," which 

 kneads the stuff into a solid mass. The machine gets very hot 

 and has to be cooled with water. The gum is then heated, molded, 

 and cut into sheets by a rapidly moving knife. Balls, etc., which 

 are made of these sheets, have to be cemented. It was not until 

 about 1850 that manufacturers of " balloons " (hollow articles) 

 began to make the endless variety of playthings with which the 

 child of the present is familiar. India rubber grinding stones 

 are made of the waste by an admixture of glass, pumice stone, or 

 emery. Kamptulicon, of English origin, invented about 1843, is 

 a mixture of rubber and pulverized cork applied to coarse cloth 

 and covered with several layers of linseed oil. It is now largely 

 superseded by linoleum (Walton's patent, 1860). Imitation leather 

 and ivory (the latter not with complete success), hevenoide (for 

 billiard balls, piano keys, etc.), baleinite, plastite (for gun ram- 

 mers, canes, whip handles, etc.), and similar products are also 

 made; even sponges. Stamps were made early in the history of 

 India rubber, and by an American, James Peck, in 1862. They 

 were ruined by the ink, and had to be abandoned until inks with 

 an aniline base came, when they were able to supplant almost all 

 their rivals. Hard-rubber dental plates are said to have been the 

 invention of Dr. Evans, an American dentist in Paris, in 1854. 

 He made several pieces for Goodyear's use in 1855. The latter 

 showed them to Dr. Putnam in this country, who, with the assist- 

 ance of a chemist and Goodyear, finally succeeded in making an 

 article which has now obtained a high degree of perfection. 

 Street-paving has been tried with success in London and Han- 

 over. It deadens the rolling of vehicles, but the cost bids fair to 

 prevent its general introduction. India-rubber horseshoes, an 



