156 GOODYEAR ON GUM-ELASTIC. 



CRUSHING AND GRINDING MACHINE. 



No. 2 represents the machine by which the gum is crushed, 

 ground, and mixed with colors, and prepared for spreading upon 

 cloth, rolling into sheets, or intermixing with fibre, for the lamin- 

 ated fabrics, called vellum, tissue, &c. 



The callenders are hollow, and heated by steam to about 200° 

 Fahrenheit. The gum, after having been chopped, cut and 

 cleansed by the machine No. 1, and thoroughly dried in the loft 

 of the manufactory, is passed between these callenders, and is 

 thus reduced to a plastic state resembling dough in consistency. 

 In this way from five to ten pounds are compounded and pre- 

 pared for spreading, by one set of grinders at one time, in about 

 half an hour. A number of these machines are required to 

 supply one set of spreading callenders. 



With suitable power and machinery, one hundi-ed pounds 

 would be crushed and prepared by one " set of grinders, in the 

 same length of time. A great proportion of this labor will be 

 unnecessary when the gum can be obtained in a pure state, 

 without being smoked, as described in the article entitled 

 " Method of a:atherin2; the Gum." 



Grinding the gum is the most tedious and expensive part of 

 the manufacture of gum-elastic, which requires great mechan- 

 ical power. It is want of adequate power and corresponding 

 machinery for this purpose, and of that only, that the inventor 

 is dissatisfied with the present state of the manufacture. The 

 mammoth machine at Roxbury, built by Mr. Chaflfee, which has 

 been alluded to, and which weighs about thirty tons, is of the 

 right class, but that has been comparatively inefficient, for the 

 want of adequate power to work it. 



For this reason, in part, and partly owing to its first cost, no 

 other has ever been made of such dimensions, although money 

 and time enough have been wasted, by the different manufac- 

 turers of gum-elastic, upon fragile machinery, which has failed 



