GOODYEAR ON GUM-ELASTIC. 



Sumatra, and Java, and also from Assam. This gum is of a 



reddish, or flesh color. It contains parts carbon, parts 



hydrogen ; the specific gravity is . It is soluble in sulphuric 



ether, and the essential oils. Turpentine or camphene is used 

 in the United States as a solvent for manufacturing purposes, 

 but naphtha has been more commonly used in England. 



It has to this time been imported into the United States at 

 about one-third the price of the manufactured bottle, and shoe 

 gum from Para, or from five to eight cents per pound. Notwith- 

 standing the extremely low price, it has not heretofore been in 

 great demand, in consequence of the quantity of small particles 

 of bark that are intermixed with it, amounting to about five per 

 cent, of its weight. 



It is evident from its appearance, that it is gathered by scar- 

 ring: the tree, and allowing it to flow down the trunk, and that 

 it is afterwards stripped off" and wound up in skeins or hanks, 

 with particles of the bark adhering to it. These hanks are 

 heaped in masses, in which state it comes as ballast with cargoes 

 of light goods, teas, silks, &c. 



Machinery has been recently applied with great success for 

 cleansing this gum, at a cheap rate, yet it is to be hoped that it 

 may hereafter be imported in a clean state, for it cannot be 

 cleansed as perfectly as it might be gathered, and a very slight 

 difference in this respect makes a material difference in the 

 value of the article. 



The second variety, caoutchouc, or gum-elastic, obtained 

 from Para, manufactured by the natives, has always been 

 esteemed the best, and formerly was the only gum which it was 

 safe to re-manufacture ; and even now, it is commonly consid- 

 ered the best, although in point of fact, it is not so. That 

 from Para which is not smoked, and that which comes from the 

 Pacific coast of South America, is equally good ; and the 

 virgin gum, when well seasoned, is better. 



This gum contains 87 parts carbon, and 13 parts hydrogen ; 

 specific gravity, according to Ure, is 0.935.* It is soluble in the 

 same way as the first variety. For some years past, the price 



• It melts at 248° Fahrenheit. 



