64 TRANSACTIONS OF THE AMERICAN INSTITUTE, 



The substances consists of India rubber mixed with emery 

 powder of any desired degree of fineness, the whole mass being 

 vulcanized at a high temperature in molds, which impart the 

 desired form to the articles. The peculiar properties which the 

 compositions possess are due to the India rubber ; wheels and 

 whetstones have long been made of emery powder held together 

 by glue, shell-lac, rosin, or burned clay, &c., but they were found to 

 be brittle ; to be liable to get out of shape, and to possess little ad- 

 vantage over native stone, Emery Vulcanite, on the contrary is 

 tough, is not liable to chip or fly to pieces, and whenever a wheel 

 is worn out of true it can be faced to any contour in a lathe by 

 using a hot iron as a turning tool. Table steels, finishing files, 

 rifles, &c., are made in this substance of any shape, and they pos- 

 sess the important property of being as effective when nearly 

 worn out as they were the first day of their use. 

 New York, December 19, 1860. 



JAMES RENWICK, 

 EDWARD W. SERRELL, 

 BENJAMIN GARVEY. 



