152 GOODYEAR ON GUM- ELASTIC. 



tories, are worked into gum-elastic felt for packing, shoe soles, &c. 

 The other advantage is, that in this business the same tools are 

 employed for its various branches, and the same operatives can 

 be turned from making one description of articles to another, 

 without delay or expense ; and a female who is employed as a 

 maker of garments one day, may become the next a good trunk- 

 maker, harness, or shoe-maker. 



MACHINERY. 



The machinery employed in the manufacture of India rubber, 

 since the first attempts to work it, has been subjected to varia- 

 tion and gradual improvement. Numerous expedients and di- 

 vers machines were early tried for chopping, grinding, and 

 spreading the gum, and also for flowing it in a liquid or semi- 

 liquid state, which have been abandoned. 



For many years the gum was only worked, after first being 

 brought to a liquid, or semi-liquid state, by the solvents, such as 

 turpentine or naphtha ; and although this method is still used 

 for the plated and fibrous fabrics and thin sheets of drapery, 

 and for the finer and more delicate fabrics, it is otherwise 

 wholly abandoned in America, where the vulcanizing process is 

 used, and the machines now in common use, in which heat and 

 pressure are employed, are substituted, for the purpose of 

 crushing and spreading the gum. 



It is now generally agreed by manufacturers in this business, 

 that the machinery, or at least the principle of it, is perfect. It 

 is hazardous to express an opinion, in this age of improvements, 

 that any machinery or thing is perfect ; but the best reason for 

 believing that this machinery does not admit of further improve- 

 ment in principle, is that no complaint is made of it. It is of 

 the simplest kind, doing the work with great rapidity, although 

 it requires great mechanical power, owing to the toughness and 

 tenacity of the gum. 



