80 GOODYEAR ON GUM-ELASTIC. 



PROF. SILLI MAN'S CERTIFICATES. 



FIRST MANUFACTURB OF DRAPERY OR SHEET INDIA RUBBER. 



New. Haven, June 15, 1836. 



Mr. Charles Goodyear has submitted to me, and to my in- 

 spection, a process by which he dissolves Caoutchouc, or India 

 rubber, with common spirits of turpentine ; and then by another 

 process he restores it again, so as to form a thin sheet, or fabric, 

 without tissue. 



This fabric is divested of the clammy qualities that exist in 

 the native elastic gum. So far as I am informed, both the pro- 

 cess and the effect are new, as has been already observed by 

 the Mechanics and American Institute in New York, as in- 

 dicated by the silver medals bestowed by them on Mr. Good- 

 year, and now in his possession. 



B. SiLLIMAN. 



I would mention that Mr. Goodyear has prepared his elastic 

 gum in my presence, by spirits of turpentine, and then brought 

 it back without mixing or blending any other substance with it, 

 so that it becomes again strong India rubber, but free from any 

 clamminess ; and feeling, when pressed between the hands, like 

 linen or cotton. 



B. SiLLIMAN. 

 June 16, 1836. 



Having seen experiments made, and also performed them 

 myself, with the India rubber prepared by Mr. Charles Good- 

 year, I can state that it does not melt, but rather chars, by heat, 

 and that it does not stiffen by cold, but retains its flexibility in 

 the cold, even when laid between cakes of ice. 



B. SiLLIMAN. 

 Yale College, Oct. 14, 1839. 



