138 GOODYEAR ON G UM- E L A S T I C. 



very adhesive, that when any two surfaces are brought in con- 

 tact, they become by sHght pressure one mass, that cannot be 

 separated. 5th. It loses its elasticity by continued tension, or 

 constant use. 6th. It has a very unpleasant odor. It has been 

 long and fully proved, that these objections and defects render 

 the native gum unfit for general purposes, as almost every article 

 is exposed to come in contact with some one or more of the 

 destructive agents mentioned. 



PROPERTIES OF HEATED OR VULCANIZED INDIA RUBBER. 



1st. Elasticity. 



2d. Pliability. 



3d. Durability. 



4th. Insolubility. 



5th. Unalterability by climate, or artificial heat or cold. 



6th. Inadhesiveness. 



7th. Impermeability to air, gases, and liquids. 



8th. Plasticity. 



9th. Facility of receiving every style of printing. 

 1 0th. Facility of being ornamented by painting, bronzing, gild- 

 ing, japanning, and mixing with colors. 

 11th. Non-electric quality. 

 12th. Odor. 



1st. ELASTICITY. 



This property of the native gum is improved and increased, in 

 the metallic or vulcanized article, both as regards strength and 

 continuance ; besides, it is hereby made available in all cli- 

 mates, and in all circumstances, whereas the elasticity of the 

 native gum is lost when frozen, or much exposed to the sun or 

 great heat. The improvement in this respect becomes in- 



