34 GOODYEAR ON GUM-ELASTIC. 



Whether any advantage will arise from the production of 

 gutta percha in this way, either as to cost or quality, it is im- 

 possible to say. From some experiments that have been made, 

 it appears, however, to possess more durable properties than the 

 genuine or native gutta percha. 



ARTIFICIAL ELASTIC GUM. 



It is a curious fact, that some of the non-elastic gums, when- 

 combined and vulcanized, will form an artificial elastic gum fully 

 equal in some respects, and superior in others, to Para India 

 rubber, and nearly as elastic as it is. 



The ingredients of which this substance is composed, are 

 chiefly gutta percha and gum-shellac, in combination with 

 other substances, submitted to the action of sulphur in the 

 vulcanizing process. Its properties, compared with the native 

 gum when vulcanized, are as follows : It is little less elastic, 

 and appears to resist the sun and weather even better than vul- 

 canized India rubber. It is peculiarly free from offensive odor, 

 and at the present prices of gum-elastic, the artificial article is 

 considerably the cheapest. It is not yet introduced, and, in 

 fact, is as yet hardly known to gum-elastic manufacturers ; but 

 from present appearances it is altogether probable that this 

 material will be found to answer, when spread upon tissues, even 

 better than Para gum-elastic. 



