182 GOODYEAR ON GUM-ELASTIC. 



ELASTIC COMPOUND. 



The term elastic compound, is applicable to the heated or vul- 

 canized gum in heavy sheets and masses, or blocks, which are 

 put in the market uncombined with cloth or other fibrous sub- 

 stances, for the purpose of being cut up and applied to various 

 uses, where elasticity is required, either by tension or compres- 

 sion. Its properties have been described under the head of 

 metallic gum-elastic. 



It is made by the licensees in sheets, threads, and masses, of 

 any form or thickness for the uses for which it is required. 



NON-ELASTIC COMPOUND. 



The materials of which this substance is compounded are in 

 some cases the same as those of the elastic compound. It is 

 made non-elastic, and at the same time flexible, by varying the 

 degree of heat in vulcanizing and the proportions of the ingre- 

 dients. Finely pulverized soap-stone or talc is added to the 

 mixture, when the compound is intended to be used for articles 

 that are much exposed to abrasion. 



