GOODYEAR ON GUM-ELASTIC. 



confirmed by those of Mr. Faraday, contains no oxygen, as 

 almost all other solid vegetable products do ; but is a mere com- 

 pound of carbon and hydrogen, in the proportion, by my results, 

 of ninety carbon to ten of hydrogen. Mr. Faraday obtained only 

 87° carbon." 



From the foregoing extracts, and the testimony of individuals, 

 together with the specimens of the inferior gums that have been 

 imported, we have ample proof that there is a gradation of these 

 productions, from the best genuine caoutchouc, down to those 

 kinds that are quite non-elastic, all of which are obtained from 

 the sap of various trees and plants.* 



Some of these trees and plants yield a similar sap which does 

 not inspissate, but which might possibly be made to do so by 

 the use of chemical agents. 



It becomes a matter of interest, and, in fact, of great import- 

 ance, to ascertain whether some of these gums, that are con- 

 sidered inferior because they are not elastic, may not serve the 

 same purposes as gum-elastic for the plating or coating of non- 

 elastic fabrics. Among the numerous varieties of water-proof 

 gums that are found in all equatorial regions, it is exceedingly 

 probable that some which are not now known in the market, or 

 even noticed in the countries where they are produced, will be 

 found to answer the above purposes, and perhaps be less objec- 

 tionable on account of odor than India rubber ; and, like all other 

 gums, resins, and bitumens that have yet been found, it may be 

 presumed that they will be changed, either alone or in combina- 

 tion with caoutchouc, by the process of vulcanization ; and it 

 may with equal probability be assumed that none of them will 

 be found which do not require to be divested of their native 

 adhesive properties by the process of vulcanization, in order to 

 render them generally useful. 



■ The tree which yields the genuine India rubber in Brazil, is very generally called the Seringa 

 tree. 



