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manufacturers endeavour to extract still more from it by 

 submitting the cane to a double, triple and even quad- 

 ruple pressure with imbibition of warm water, with the 

 result that they obtain as high a percentage as 80 per cent. 

 With the same purpose, in some mills the diffusion-method 

 was applied by which up to 90 % of sap was extracted. 

 This method did not consist of pressing the cane, but in 

 cutting it in slices, which were then washed. This method 

 is no longer applied. 



The sap obtained by pressure subsequent to its 

 transfer from the press to the weighing tanks, is filtered 

 and purified. The purification in many mills is obtained 

 by warming the sap, after mixing it with lime, boiling it 

 in pans, while taking off the scum, and by precipitating 

 it. Then the sap is submitted to a pressure in filter- 

 presses, until only dry cakes are left, which, however, still 

 contain much sugar. 



There is another method which is more expensive, 

 but on the other hand better. It is the saturation- or car- 

 bonisation-method. The sap is saturated with lime and is 

 then precipitated with carbonic acid, after which operation 

 it is pressed in filters. 



The purified sap is then transferred to an engine 

 of triple or four-fold power, where it is evaporated under 

 a gradually decreasing atmospheric pressure and condensed 

 to 30*^ Beaume. This sap undergoes another purification in 

 elimination-pans or in filters and is then boiled in the 



