4o6 CHAPTER XIX 



installed with a combined capacity of 40 cu. ft. per ton-cane-hour there would 

 then be 15 crystallizers each holding one pan strike. If, as is often the case, 

 the crystallizers are laid out in a double row, 16 would be the number installed. 



Boiling Routines in White Sugar Manufacture. — The same general 

 principles apply to boiling in white sugar manufacture as in that of raw, 

 with respect to which this chapter has been written. In details, however, 

 there are several important differences. In the first place, owing to the 

 necessity of washing the sugars, there results a much greater quantity of 

 molasses to be handled, and this material suffers an increase in purity 

 over and above that of the mother liquor. Secondly, processes employing 

 low sugars as seed grain are impossible, since a discoloured nucleus in the 

 crystal Would result ; the use of a pied-de-cuite or of high grade sugar as 

 seed is, however, permissible and useful when a large crystal sugar is de- 

 manded. A third point of difference lies in the treatment of the low grade 

 sugars ; evidently these sugars cannot be mixed with the white sugars, 

 and they have to be marketed as low grades or else remelted in the juice 

 and passed again through the process of defecation. This procedure is, 

 however, not altogether to be recommended, as dark-coloured bodies are 

 re-introduced into the juice. Finally, it is to be remembered that brightness 

 and transparency in the material entering the pans is of perhaps more 

 importance than is colour. 



A two-massecuite process is generally impossible in the manufacture of 

 white sugar, and three boilings will nearly always be necessary. The 

 first boiling is made from syrup alone, with or without the return of purging 

 syrup {vide page 426), or of the rich molasses resulting from the washing 

 of the sugar in the centrifugals, provided these are separated from the 

 actual mother liquor. The second boiling is made from these last-mentioned 

 materials, sometimes on a footing of first massecuite and sometimes grained 

 separately. This massecuite affords a white soft-grained moist sugar very 

 popular in the Orient ; it may also be mixed with first sugar, only one 

 quality of white in this case being marketed. The molasses resulting from 

 this second boiling should be of purity sufficiently low to afford a low grade 

 massecuite to be separated into a low grade sugar and waste molasses. 



REFERENCES IN CHAPIER XIX. 



r. U.K. patent 5518 ot 1900. 

 2. Sucrdrie Beige, Nov., 1898, 



