THE CONTROL OF THE FACTORY. 



If the weight of wet commercial product is required, it is expressed hy the 



formula : j m 100 



j (s m} Brix of the Sugar 



The only reliable basis of calculation and method of comparison as between 

 factories is, however, obtained by referring everything to pure sugar and we 



then have 



(j-m) 100 .. . . , . s (/-Q * 



Sucrose = 7 f X ~^-r- X sucrose per cent, in commercial product = - -. 



j(8m) Brix j (s m) 



Expressed in words, this formula means that, with an initial purity of, say, 90, 

 a purity of 98 in the product, and a purity of 45 in the waste molasses per 

 100 sucrose originally present, there is obtained of sucrose in the commercial 



'*S{ESH-- 



More sugar than this cannot possibly be obtained, and the nearer the actually 

 recorded results come to the calculated ones, the less have been the losses of 

 sugar in filter presses, in entrainment, &c. 



In cane sugar practice it is usual to accept the direct polarizations of 

 juice and sugars as giving the percentage of sucrose, and to use the Clerget 

 process only for the waste molasses. For the proper application of this control 

 true total solids and true sucrose deterihinations are essential, and these should 

 find a place in the routine work of every sugar factory where accuracy is more 

 highly considered than convenience. Difficulty arises in the application of 

 this control in considering what should be taken as the initial purity, and 

 whether the losses in press cake, entraiument, &c., should be considered as 

 avoidable ; these losses are not necessary in the same sense that molasses losses 

 due to the formation of a definite syrupy compound between sucrose and 

 saltsf are necessary, and in so far as they are determinable may be introduced 

 into the equation as indicated below. As regards the initial purity introduced 

 into the equation, that of the syrup might be taken as allowing for the 

 removal of impurities in the press cake and in scale formed in the evaporators. 

 The formula then appears as 



Available sugar = (sugar in mixed juice known losses) -77^ L 



J ( 8 m ) 



j, *, m being the true purities of the syrup, the commercial product, and the 

 molasses respectively. The formula established above can be put in the form : 



Commercial sugar per cent, on massecuite = J" , , 



Jf t (s m) 



where B m and B s are the total solids in the massecuite and sugar, and /, *, m 

 are the purities of the massecuite, juice, and molasses. 



* Formulse of similar form and obtained by different reasoning have been proposed 

 by Winter, Geerligs, Rose, Carp, Lohman, and Hazewinkel in Java, between the years 1894 and 

 1903. A complete discussion of these is given by Geerligs in the Dutch edition of ' Cane Sugar 

 and its Manufacture.' 



t Cf. Chapter XIX. 



509 



