160 GOODYEAR ON GUM-ELASTIC. 



dissolving India rubber, for a long time after it was practiced to 

 some extent, to be considered by many a secret, and a thing 

 difficult to do, when it afterwards appeared that it was one of 

 the simplest and easiest things possible, when it was proceeded 

 with in the manner described. 



The machine for spreading the gum in a liquid state, rep- 

 resented by No. , is simply what is called a straight-edge or 

 knife, which applies the gum in exceedingly thin coats to the 

 cloth, as it passes under it in the form of an endless belt. This 

 was adopted as the best way, after various methods had been tried 

 of flowing the gum, applying it with brushes, &c. The method 

 now practiced enables the manufacturer to use the gum as a var- 

 nish or thin coating upon cloths, which, otherwise, it is almost 

 impossible to do perfectly, or to any advantage, on account of the 

 stringy quality of the liquid, and the sudden evaporation of the 

 solvent. 



Dissolved gum has more commonly been spread by callen- 

 ders, such as represented by No. G, worked when they are cold, 

 or a little heated, and while the gum is in a semi-liquid state, or 

 about the consistence of stiff" dough ; which, although it may be 

 thoroughly dissolved, requires to be thoroughly ground or 

 kneaded before it will spread evenly, or without what is termed 

 by the workmen, crawling. 



The cloth, when coated by this machine with successive layers 

 of gum to form the thickness desired, is wound up on an open 

 reel, when each coat is left to dry before another is applied ; 

 two or three coatings are commonly applied to form a waterproof 

 cloth. The process is a slow one, making at the rate of about 

 three hundred yards per day for one machine, but finer work can 

 be done in this way than with the steam-heated callenders, and 

 much more expeditiously than with the knife, or machine No. 5. 

 The most perfect embossed fabrics are also made in this manner, 

 by spreading the gum upon any figured fabric which may be used 

 as a pattern. By this machine, as well as by the knife, the most 

 perfect sheets of drapery are made by spreading the gum upon 

 either a japanned or vulcanized India rubber cloth. In refer- 



