HAKD COMPOUNDS. 213 



HARD COMPOUNDS. 



Caoutchouc enamel. Ivory. Buck-horn. Whalebone. Boards. Veneers. Enameled ware. 



Before it was found that gum-elastic and gutta-percha, in 

 combination with other gums and resins, could be heated, so 

 as to form a hard compound, the greater portion of this work 

 was written and stereotyped. It was, however, felt that a sub- 

 stance was much to be desired which might be substituted for 

 bone, whalebone, buffalo-horn, and ivory, (all of which are 

 gradually becoming scarce,) and one which could be moulded 

 like gum-elastic or gutta percha ; and it was anticipated that 

 if this object should be attained, great improvements in many 

 arts and manufactures would probably result from such dis- 

 covery. These anticipations have been more than realized, by 

 means of a hard compound of heated caoutchouc. Although the 

 manufacture is as yet no further advanced than to produce an 

 assortment of specimens, their importance is evidently such that 

 they deserve to hold a prominent place in treating of the prop- 

 erties of heated gum-elastic. 



Owing to the difficulty of applying one term to these com- 

 pounds, which will give a correct idea of their various proper- 

 ties, they are treated of as imitations of the following substances, 

 namely, enamel, ivory, buck-horn, whalebone, etc. They 

 not only make good imitations of these materials in appearance, 

 but they are also in reality superior in quality, in some respects, 

 to the natural substances. 



The hardest of these compounds resembles marble ;* that 

 which is less hard, ivory and buck-horn ; that which is still 



* For the modification which gives it its extreme hardness, the writer is indebted in good peirt 

 to his younger brother, Nelson Goodyear. 



-t^iSh 



