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The World's Commercial Products 



By permission of th 



VACUUM PANS 



as fuel. It is estimated that in this process about ninety-five per cent, of the sugar is extracted 

 from the cane. Whereas in ordinary single crushing we only obtain about seventy-five per 

 cent., in double crushing eighty-three to eighty-eight per cent., and in triple crushing ninety to 

 ninety- two per cent. 



Defecation and Filtration. The juice flows from the mill as a dark, greenish-yellow liquid, 

 not attractive to the eye, but with the pleasant odour of sugar-cane juice and distinctly sweet 

 to the taste. Analyses show that cane juice as expressed contains, on an average at any 

 rate in the West Indies, about fourteen per cent, of cane-sugar. In addition the juice has two 

 kinds of impurities. There are small pieces of the tissues of the stems which have come over 

 from the mill, accidental additions, particles of dirt, etc. There are also impurities dissolved 

 in juice, the albuminoids, salts, and other normal ingredients of the sugar-cane sap, which, 

 although perfectly harmless, are not sugar and must be removed. 



Large particles are readily got rid of by simple straining. After this has been done 

 means are taken to (1) coagulate and thus render insoluble the previously dissolved albu- 

 minoids and other substances, and (2) to remove these with any other material which has 

 •escaped the rough straining process. 



The coagulation of the albuminoids is effected partly by heating the juice. This has another 

 important result inasmuch as it kills the ferments naturally present in the plant, and prevents 

 further changes going on in the composition of the juice. 



It is also well known, however, that if a solution containing cane-sugar is heated and 

 particularly if the mixture is slightly acid, as sugar-cane juice is as it leaves the mill, some 

 ■of the cane-sugar will be inverted, as it is technically termed, into other forms of sugar which 

 .are of less value to the manufacturer. To guard against this a certain quantity of lime, in 

 the form of milk of lime, is added to the juice. The lime plays more than one role. It removes 



