THE CONTKOL OF THE FACTORY. 



1. The Density of the Last Mill Juice. On the supposition that the density 

 of the juice is constant throughout the cane (a supposition that is not very far 

 from the truth) it is easy to ohtain the density of the last mill juice when 

 complete admixture is assumed. For example, let canes with 12 per cent, of 

 fibre be crushed until they contain 45 per cent, of fibre ; then the weight of juice 



remaining in the megass per unit weight of cane is - = '1467; 



*45 



let this juice be of density 18Erix, and let water 20 per cent, on cane be 

 added with complete admixture. Then the density after mixture, i.e., the 



* 1467 x 18 

 density of the last mill juice is = 7*61. 



In Table I., at the end of this section, is calculated for a single macera- 

 tion process the density of the last mill juice for degrees Brix in the normal 

 juice from 15 to 22, and for added water per 100 cane from 10 to 50, the 

 dry crushed megass containing 45 per cent, of fibre, and the cane containing 

 12 per cent, of fibre. As the mixture becomes less complete, less solids are 

 extracted, and the density of the last mill juice will fall. This table and 

 calculation is introduced as a means of checking the efficiency of the added 

 water. 



2. Comparison of Last Mill Juice with the Residual Juice in Megass. A 

 number of years ago it was the custom in Java mills to work out a * coefficient 

 of admixture of added water ' on the following lines : 



Sugar per cent, in megass 



Sugar per cent, in residual luice in megass=i- : X 100. 



1 fibre per cent, in megass 



Sugar per cent, in last mill juice 



Coefficient of admixture = jp . . . . 



Sugar per cent, in residual ]uice 



This figure does not appear in the more recent reports, and for this reason 

 the writer believes that it is no longer employed. 



The figure as it stands is liable to misinterpretation ; if a small quantity 

 of water has been used a high coefficient must necessarily result, even if no 

 admixture whatever has taken place ; and as the residual juice always contains 

 less sugar than that already expressed, an accurate comparison on these lines is 

 impossible. 



3. The Relation between Added Water per cent, on Canes and Dilution 

 per cent, on Normal Juice. As the weight of the canes is greater than 

 the weight of the normal juice, it might appear that the figure giving the 

 added water per cent, on canes would be less than that giving the dilution per 

 cent, on normal juice ; a great part of the water added does not, however, 

 enter into the mixed juice, but passes away with the megass, and with 

 complete admixture the figure expressing the added water per cent, on canes 

 will always be considerably greater than that expressing the dilution per cent, 

 on normal juice. To obtain a comparative table of these figures one proceeds as 

 follows : The degree Brix is taken as being uniform throughout the cane ; let 



505 



