216 GOODYEAR ON GUM - E L A S TI C . 



vantages are obtained from uniting or welding hard steel with 

 soft iron. 



This is exemplified in its use for the mouth of a bottle, the tube 

 of a globe or life-preserver, where it is first cemented to, and 

 afterwards vulcanized with the article, in which case it becomes 

 a substitute for metal, far better than metal, because it does not 

 corrode, and is perfectly joined, so as to form part and parcel 

 of the article. 



Some of the advantages anticipated from its peculiar proper- 

 ties, are alluded to as relates to various articles which are speci- 

 fied in the second volume of this work. For further explanation 

 of the method of uniting the hard to the elastic and flexible 

 fabrics, see Vol. II., Chapter XII., MiHtary Caps ; and Chapter 

 XX., Skates. 



CAOUTCHOUC BUCK-HORN. 



The same substance which has been described as imitation 

 ivory, makes, also, when pressed in moulds, a good imitation of 

 buck-horn, which will answer all the purposes to which buck 

 horn is applied. 



CAOUTCHOUC WHALEBONE. 



In the manufacture of the hard substances which have been 

 described, it is not surprising that between the very hard com- 

 pounds, or India rubber porcelain and ivory, and the very soft 

 one of drapery, there should be produced a material which re- 

 sembles whalebone very closely. This substance has the pecu- 

 liar odor of horn or whalebone. The ingredients and proportions 

 differ very little from those of the ivory ; a greater degree of 

 heat, however, is required in the manufacture of the whalebone. 



