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cane it becomes the last instead of the first of the chain. All the cells 

 are successively treated in like manner. Thus as little water as possible 

 is used to dissolve out the sugar-a very important factor, since all the water 

 will have to be evaporated off. This so-called diffusion juice con- 

 tains approximately two thirds the percentage of sugar found in the mill 

 juice of the same cane ; or in other words, two thirds of the " diffusion 

 juice " may be considered as pure juice and the remaining third as water 

 added to it. 



The juice, no matter how obtained, contains in addition to water 

 and sugar, a considerable portion of other compounds. Among these 

 are albuminoids, amides, colouring matter, organic acids, gums and 

 mucilages. All these have to be removed as much as possible before 

 the evaporation of the water is begun. Frequently sulphur dioxide, 

 produced by burning sulphur, is first ueed as a bleaching agent ; but 

 unless it is decided to produce the highest grades of sugar directly at 

 the sugar house, the advisability of its use may be somewhat question" 

 able, since it has a tendency to reduce the sugar yield. Lime is 

 invariably used as a clarifying agent, either alone or directly after the 

 use of sulphur dioxide. It is generally added, suspended in water, to 

 the juice, in large iron tanks generally enough to make the juice slightly 

 alkaline. The mass is slightly boiled and the skum removed from the 

 top several times, or rather just as the scum forms The precipitate is 

 allowed to settle and the clear liquid drawn off. A further clarification 

 and the removal of any excess of lime by the use of phosphoric acid 

 will probably be adopted in the near future. The skimmings and set- 

 lings are pressed through heavy canvas filters, and the liquid separated 

 from them, which of course contains a considerable percentage of sugar, 

 is added to the other portion of clarified juice, which is now ready to be 

 boiled into sugar. The solid portion is thrown away or used as a fertilizer. 



The evaporation of the juice is generally carried on in two stages. 

 The first, to near the point of saturation ; and the second to such a con- 

 sistency that it will still run readily out of the vessel in which it has 

 been boiled. Both these concentrations are almost invariably conducted 

 in a partial vacuum. The vacuum is increased with the concentra- 

 tion of the juice. The initial evaporation is generally done in two or 

 three separate vessels, the steam of the first being used to heat the 



