IXDIA RUBBER AND GUTTA-PERCHA. 685 



American paiteiit, are announced, for special use on asphalt pave- 

 ments. 



It is impossible to mention all the uses to which India rubber 

 is applied, and reference can only be made, in concluding, to two 

 more, very important ones. It is at present finding increasing 

 favor in tires for vehicles, the solid kind being most frequent, 

 though occasionally pneumatic-tired equipages are seen. Han- 

 cock claims to have made the solid kind for her Majesty in 1846. 

 The recent tire of American invention with wires running 

 through it is thought, in this country, to be the best, as double 

 the quantity of rubber of better quality is used, which secures 

 greater elasticity, and vastly cheaper, from better rim- construc- 

 tion and because worn spots may be cut out and renewed. The 

 bicycle industry, it is estimated, is turning out, in 1896, in the 

 United States alone, six hundred thousand bicycles and one 

 million and a half pairs of pneumatic tires, which will require 

 about one thousand tons of rubber. The output in England is 

 about the same, that country and the United States producing 

 seventy- five per cent of the wheels manufactured. A writer on 

 this subject (Hawthorne Hill) recently said that probably not 

 more than four per cent of the output of rubber is used in the 

 bicycle trade. 



The discovery of gutta-percha, which seems to unite all the 

 advantages of India rubber, excepting elasticity, without its dis- 

 advantages, has sometimes been attributed to the traveler Trades- 

 cant, who brought it to England, where it was known as mazer- 

 wood. It was neglected and soon forgotten. To an Englishman, 

 Dr. Montgomery, is due the merit of having brought the impor- 

 tance of the new article to the attention of the world of science 

 and industry. Hearing of it at Singapore, in 1822, he procured 

 specimens from the natives, who collected it in the neighboring 

 forests, and formed it chiefly into axe handles by malaxation in 

 boiling water. He found it differed materially from elastic gum. 

 Having proved that it retained the shape on cooling, imparted to 

 it in boiling water, v/hile recovering its hardness and primitive 

 tenacitj^. Dr. Montgomery thought such a substance could serve 

 better than rubber for certain instruments of surgery, and com- 

 municated his views to the Medical Board of Calcutta in 1843, 

 which warmly indorsed the idea. Ho also sent specimens and a 

 study of the product to the London Society of Arts, and received 

 from it a gold medal in recognition of his important discovery. 

 According to Dr. Giitzlaff, the celebrated missionary, gutta-percha 

 was known in China long before it appeared in Europe, though 

 certainly not gathered there. 



Gutta-percha, like India rubber, is obtained from the juices of 

 certain trees and climbers. The best is produced by a tree, the 



