82 GOODYEAR ON GUM-ELASTIC. 



2d. Mechanical tests. 



It possesses all the usual properties of common gum-elastic, 

 but it far surpasses the latter in the degree of these properties. 



Its tenacity, or the force which it opposes to rupture, is much 

 greater than that possessed by ordinary gum-elastic ; we have 

 not submitted it to direct measurement, but a simple practical 

 test convinced us of its superior tenacity. 



When opposed to great degrees of cold, even below 32°, it ap- 

 pears to be undiminished in its elasticity, flexibility, and tenacity, 

 in which valuable property it diftei's so strikingly from ordinary 

 gum-elastic, that this alone, if it possessed no other superiority 

 over common gum, would entitle it to the praise of being the 

 greatest improvement in the manufacture of gum-elastic. ■ 



We have had pieces of it lying for two years in our laboratory, 

 and during the same period have repeatedly employed portions 

 of it for connecting apparatus, and for other purposes, and we 

 find that it resists mechanical abrasion, as well as chemical 

 action, powerfully ; nor have we found it touched by vermin, nor 

 altered in the slightest degree. 



Besides the above properties, resulting from experiments, there 

 are others evident to those who have examined the goods manu- 

 factured from the metallic gum-elastic composition ; such as the 

 ease with which it may be wrought into an infinite variety of 

 goods, adapted to almost every variety of purpose ; the ease 

 with which it receives color, the finest lines of printing, &c. ; 

 but as these properties may be more or less understood by a 

 simple inspection of the goods, we forbear taking farther notice 

 of them. 



In conclusion, we cannot but draw the inference from our 

 own experiments, and from an examination of the different kinds 

 of fabric made from this singular composition, that it far sur- 

 passes all other attempts made to manufacture gum-elastic 

 goods. 



Respectfully yours, 



(Signed,) Jas. C. Booth and H, M. Boye. 



