74 GOODYEAR ON GUM-ELASTIC. 



particularly of one that has been so much and so long discred- 

 ited and disused. 



This view of the subject is taken only because the matter is 

 not understood. The different manner of using it is in fact 

 equivalent to a new discovery ; and the rendering of any art 

 available which has been once condemned and disused, is even 

 more difficult than it is to introduce an invention entirely new. 



It is less understood that there is in fact no rivalry between 

 the two processes ; in other words, vulcanization is not ren- 

 dered less valuable by solarization : they apply to very different 

 classes of fabrics. While light and the sun's ra\'s operate upon 

 extremely thin coated or plated fabrics, the more intense and 

 artificial heat used in vulcanization accomplishes the more diffi- 

 cult result, of changing the nature of masses of gum of any 

 desired thickness. 



