CANE SUGAR. 



massecuites gave a larger yield, not because more sugar was present as 

 crystals, but because a larger proportion of the crystals were recovered. 



That the size of the crystals has much to do with the removal of molasses 

 is self-evident, when it is remembered that the larger the grain the less is the 

 area of contact for the molasses, and consequently the latter are the more 

 easily removed ; Geerligs demonstrated this by allowing syrup to drain from 

 massecuites in which the size of the grain varied; his results are given 

 below : 



Diameter of the grain 



m.m. 

 3-0 

 2-0 

 1-5 

 1-0 

 0-5 



Syrup run off; 

 grms. 



300 

 265 

 200 

 115 

 20 



Mixtures of 600 grms. sugar crystals and 400 grms. of syrup, as indicated 

 above, were allowed to drain for three days, the larger the diameter of the- 

 crystals the greater the quantity of syrup run off. 



This experiment has however a double interpretation, for the rate at 

 which a syrup is desaccharified depends on the area of crystal surface in 

 contact with molasses, so that apart from questions of purging, a small grain 

 and large surface is often required ; the processes followed and kind of sugar 

 produced are the factors which control the size of crystal to be made. 



The general rules for the treatment of massecuites may then be 

 summarized. Impure massecuites with purity under, say, 80-81, give best 

 results when not boiled too close and when cured hot ; purer massecuites may 

 be boiled to a less water content and should be cured cold ; as even a grain a& 

 possible should be made. This is a point where the skill of the pan boiler is 

 shown, and is really of very great importance ; a juice which, in the hands of 

 one pan boiler, gives a massecuite from which 56 per cent, to 58 per cent, of 

 crystals are recovered may, when boiled by one more skilful, give a recovery 

 of 60 per cent, to 62 per cent. 



386 



