84 



MANUFACTURE OF SUGAR. 



even this may be rendered profitable by the aid of a well 

 contrived machine for affusion and repressure, for the pur- 

 pose of fermentation and conversion into rum, along with 

 the uncrystallizable melasses. Rollers such as described 

 would vary from four feet in length for small mills, to six feet 

 in powerful ones, and the diameter should never be under 

 25 inches, although 30 inches would be preferable, as such 

 a mill would feed more easily and laminate more perfectly, 

 In calculating the velocity with which a roller should revolve, 

 its diameter must be considered, as the number of revolu- 

 tions per minute becomes a most indefinite term when 

 applied indiscriminately to rollers of different diameters. 

 Thus if w^e suppose two rollers of 24 and 30 inches respec- 

 tive diameter, to be each making two revolutions per 

 minute, the surface or periphery of the smaller would be 

 travelling only 12 feet, while that of the larger would be 

 going at the rate of 15 feet per minute. The speed should 

 never exceed 15 feet per minute, or two revolutions of a 

 cylinder of 30 inches diameter. 



It is evident that when the size of the cylinders is in- 

 creased, a greater force is required to set them in motion, and 

 overcome the immensely increased resistance of the canes. 

 This is accomplished by augmenting the size of the gear- 

 ing wheels in proportion to the driving pinions, or by 

 introducing another wheel and pinion, which has the 

 double effect of increasing power and diminishing motion. 

 Those which I have lately seen have had the gearing w r heels 

 increased in size to produce the required effect. It is 



