WARMING MACHINE. 157 



simply in consequence of its being too light, to have built many 

 such sets of machinery as that alluded to. 



But were a number of sets of such machinery employed 

 with a thousand horse power, either of water or steam power, 

 instead of from twenty to fifty horse power, which are now 

 commonly employed, an immense saving would be made in this 

 manufacture. With a number of sets of mammoth machinery, 

 and adequate power, one complement of workmen, buildings, 

 foremen, &c., would then accomplish in this department of 

 the manufacture nearly the same amount of labor as is now 

 accomplished by a great number of smaller powers and light 

 machinery. 



The great tenacity of the gum requires that the particles 

 should be separated before it can be spread, and in order to do 

 this when it is not dissolved, it becomes necessary to grind, or 

 rather to knead it with callenders, as it cannot be ground in mills 

 like granulated substances. Many attempts have been made to 

 do this in the early stages of the manufacture, which were 

 abandoned on account of the great power required. This is now 

 done at most of the India rubber factories, by grinding or knead- 

 ing about six or eight pounds at one time, until it is finished in 

 the space of about twenty or thirty minutes. To conduct the 

 manufacture to the best advantage, the machinery and power 

 should be heavy enough to grind one hundred pounds in the 

 same time. 



Before the gum is spread, it is first placed in either a wooden 

 or iron box, and warmed, and is passed from thence to the 



WARMING MACHINE. 



No. 3 ; which, in its construction, always resembles closely, if 

 not exactly, the machines for crushing and grinding. This 

 machine is used for warming up the gum, and for the purpose 

 of spreading it, after being ground in No. 2. The cylinders are 

 hollow, and heated by steam, like No. 2, to about 200° Fahren- 



