CANE SUGAK. 



Geerligs* Method. 15 This method depends on the observation that sugar 

 crystals themselves only contain a trace of ash, the ash of commercial sugars 

 being due to the accompanying molasses ; hence, in a massecuite the ash is 

 due solely to the molasses. Determine the percentage of ash in the massecuite 

 and in its molasses freed from fine grain by filtration through glasswool ; as an 

 example, let the massecuite contain 2*25 per cent, and the molasses 

 6-07 per cent, ash ; then the percentage of molasses in the massecuite is 



:2'25 



- X 100 = 37-07 per cent. ; the remainder 63-93 percent, being crystallized 



sugar. 



Method used by the Writer. On the plate of a Bucbner funnel, arranged 

 as in Fig. 256, is placed a layer of glasswool, after which the funnel is filled 

 ^vith the massecuite under analysis. On connecting to the vacuum the 

 molasses, entirely freed from crystals, passes through. 



Let x and y be the proportions of sugar in the massecuite and filtered 

 .molasses, respectively, and let 8 be the proportion of sugar as crystals per unit 

 of massecuite. 



Then x =. (1 ) y -f *, whence s = - - 



This equation gives the amount of crystals of pure sugar ; actually, in 

 practice, the crystals are obtained with an adhering layer of molasses which 

 increases the weight as indicated by this analysis. 



These methods have been described as applicable to massecuites ; they 

 are, of course, applicable to molasses to determine the quantity of fine grain 

 which has been separated on cooling or is present after having passed through 

 the mesh of the centrifugal basket. 



Rapid Scheme for Technical Control. 1. Weigh out from 150 to 200 grins, 

 of material, dissolve in water, and make up to 1000 c.c. 



2. Determine the density of this solution with the Brix hydrometer; 



^X^XlOOO 

 then the degree Brix or apparent total solids of the massecuite is 



where B and d are the degree Brix and the density of the solution respectively, 

 and w is the weight of the material taken. 



3. Obtain the polariscope reading of the solution exactly as described for 

 the juice. Then the apparent per cent, of sugar in the massecuite is 



T0~" wnere P i 8 the polarization of the solution, N the normal weight 



of the polariscope, and w the weight of material taken. 



4. The apparent purity is obtained by dividing the apparent sugar per- 

 centage by the apparent Brix. 



In many cases in rapid technical control it is only the apparent purity 

 that is required ; it is then only necessary to make up a solution to any con- 

 venient density and determine the apparent purity of this solution exactly as 

 described for juice. 



486 



