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MANUFACTURE OF SUGAR, 



The rollers should always be disposed horizontally, an 

 arrangement which possesses great advantage over the 

 vertical rollers in the ease and regularity of feeding, and in 

 the equable wear of the surface; nevertheless objections 

 have been raised to it, which have, however, been success- 

 fully combated. Dr. Evans says, " One evil attending the 

 mill composed of three horizontal rollers is, the re-absorp- 

 tion of a part of the cane juice, by the squeezed but 

 spongy megass. Another and much greater one is, the 

 loss of power caused by the oblique direction of the crush- 

 ing force, and the inordinate amount of friction." 



These remarks Dr. Mitchell ably controverts as follows : 

 — u Re-absorption certainly takes place, but to a most 

 trifling degree, when the motion is slow, but is much more 

 than counterbalanced by the increased facility of feeding. 

 The second is a chimera, for the rollers, however placed, 

 so they be parallel, must lay hold of the cane, and deliver 

 it at a tangent, to the force developed at their periphery. 

 Friction has equally little to do with the position of the 

 rollers. The conclusions of Rennie and Morin are, First, 

 Friction is simply as the pressure without regard to surface, 

 time, or velocity. Second, Its amount is independent, for 

 one and the same body of the extent of surface of contact ; 

 hence it is neither increased by turning vertical rollers into 

 horizontal, nor by lengthening the latter, while the pressure 

 remains equal," &c. &c. 



In the construction of rollers for a horizontal mill, two 

 things should be borne in mind. First, That the length 



