THE EXTRACTION OF THE JUICE BY :\nLLS 



197 



variation, and designs derived from and different from the isosceles com- 

 bination are found, as well as others with quite a different origin. These 

 variations will be described present!}', together with some account of the 

 preparatory- de\'ices and the accessories to a milling plant. 



The Development of the Three-Roller Mill. — Pressure of some sort has 

 been used from primitive times in order to extract juice from the cane. 

 Perhaps the earliest method is that which is still used by the autocthons 

 of South America, and until recently by the ryots of British India. This 

 method is based on the pestle and mortar, the latter element 

 being furnished \\ith a hole in the bottom, whence the juice 

 drains. A hollowed tree stump is often utilized as the mortar. 



The earliest extant account of sugar manufacture is to be 

 found in the Gesfa Dei per Francos, written in the twelfth 



Fig. 88 



centurv, and here is mentioned a screw press of some nature as being used by 

 the Saracens in the Levant in the extraction of juice. 



Willughby,'* in the seventeenth century, describes a cane mill, evidently 

 developed from an early t\"pe of com grinder as used in Spain. It consisted 

 of a wheel rotating about its axis and also about the end of a shaft attached 

 to itself. The path of the wheel was a circular perforated gutter, in which 

 the cane was laid. He also saw mills of two horizontal wooden rollers 

 covered with iron plates. 



The roller mill was used in India at a ver\- early date. A report prepared 

 by officials of the Hon. East India Co., of date 1822, shows two types. In 

 one the rollers are vertical, and are provided with co-acting spiral gears 

 carved out of hard wood ; in the second the rollers are horizontal and each 

 is rotated independently of the other by manual power through wheels 



