INADHESIVENESS, IMPERMEABILITY, ETC. 141 



6th. INADHESIVENESS. 



The great adhesiveness of the native gum, after being manu- 

 factured and applied to use, v^as one of the chief objections 

 to it. 



The heated or vulcanized gum is entirely free from this 

 objection, having all the dryness of leather or cloth, and that 

 which forcibly illustrates its inadhesive property, is the fact that 

 no way is yet found to unite it firmly, even when it is desired ; 

 and the art of making the fabrics adhere, after they are vulcan- 

 ized, if one could be found, would be very valuable, since the 

 fabrics might then be made up, and cemented by the purchaser, 

 as well as the manufacturers. 



The property of inadhesiveness involves the important quality 

 of cleanHness, and facility of being cleaned when soiled. In the 

 perfection of this quality it resembles glass. 



7th. IMPERMEABILITY 



TO AIR GASES AND LIQUIDS. 



This is a property of the native gum, which is fully re- 

 tained in the vulcanized material, and in the " fabrics" gen- 

 erally. It is improved for containing or resisting water and 

 liquids, as it is not softened by them like the native gum, but it 

 cannot be stated that it is more impervious to air and the 

 gases than the native gum. 



8th. PLASTICITY. 



One of the properties of this material, which contributes 

 primarily as much as any other to enhance its value to man- 



