95 



second and that of the second to heat the third. The final concen- 

 tration is accomplished in a large iron vessel containing seldom less than 

 five to six tons of sugar, or rather of a mixture of molasses and sugar, when 

 the boiling is completed. 



The molasses is separated by centrifugal force from the crystals c 

 sugar suspended in it. In making the finer grades of sugar, the molasses 

 still clinging lo the sugar crystals is washed off either with steam or by 

 the use of water. It a weak solution of stannous chloride is used in 

 place of the water a sugar having a rich amber colour (Demarara sugar) 

 is obtained. By great care in the manufacture and a liberal use of water 

 in the centrifugal it is possible to make a sugar directly from the juice. 



This sugar would be difficult, if not impossible, to distinguish from a 

 productrefinedwithanimalcharcoal. To get rid of the waterstillclinging to 

 the crystals, the sugar is dried in a slightly inclined, horizontal, heated, 

 rotating cylinder called a gran ulator. The sugar is called granulated and 

 contains over 99% of sucrose. However, comparatively little sugar is 

 made of this grade in the sugar houses, there being considerable loss by 

 washing in the centrifugal. The greater portion is sold to the refiners. 

 Here it is redissolved, filtered through animal charcoal and again boiled 

 into sugar. 



To produce a good quality of sugar, it is necessary to have the 

 crystals of uniform size and as large as they can conveniently be made. 

 Small crystals are liable to choke the sieve of the centrifugal, and prevent 

 the easy and perfect separation of the molasses from the sugar, and this 

 of course reduces the quality. The preliminary evaporation to near the 

 point of saturation, gives the sugar maker a more perfect control of the 

 crystallization. The process is briefly as follows : The pan in which 

 the boiling is done is partially filled with the already concentrated juice, 

 called syrup. This is boiled down till the crystallization has just begun. 

 A smallquantityof additional syrup isthendrawn in. Thus by very slightly 

 diluting the boiling mass the tendency to prevent any further crystals from 

 forming is brought about. The amount of syrup added from time to time 

 must be enough to do this but not so much as to redissolve the crystals 

 already formed. The evaporation going on all the time, and no new 

 crystals being allowed to form, those already there must increase in size 

 and that uniformly. The smaller the number of crystals relative to the 

 size of the pan, the larger they can be made to grow. 



