Diffusion Compared with Double Crushing. 7 



lib. of coal evaporates 6 lbs.) ; 3*08 tons are therefore 

 equivalent to 15*4 cwts. 



Assuming that with diffusion we should obtain 14 

 per cent, more sugar, 9"6 tons of canes will produce 

 I ton of sugar, and if we assume that the canes contain 

 13 per cent, of woody fibre and that the double-crushed 

 chips contain 50 per cent, of water, these 9*6 tons of 

 canes will produce I'Sy tons of megass or double-crushed 

 chips. These chips, if the percentage of water is the same 

 as that in double-crushed megass, should be as valuable 

 as fuel lb. for lb. ; taking therefore 4*4 tons of such 

 megass as equivalent to i ton of coals, 1*87 tons are 

 equivalent to 8*27 cwts. 



Let us turn now to the increased evaporation required 

 in the case of diffusion, per ton of sugar; but we may 

 remark in passing that in addition to this, the water 

 of diffusion has to be kept hot during the whole time 

 diffusion is going on, and that this must involve a 

 continued loss by radiation and otherwise, thus necessi- 

 tating an expenditure of fuel over and above what 

 would be required for evaporation and cleaning alone. 

 A ton of sugar with fairly good juice can be obtained 

 from 1,700 gallons. With a dilution of 30 per cent. 

 2,210 gallons would be required or an addition of 510 

 gallons of water. Assuming that i lb. of coal will 

 evaporate 12 lbs. of water, we shall require 425 lbs. of 

 coal or 3'77 cwts. per ton of sugar to bring the juice to 

 its normal density. We have already seen that the 

 theoretical loss in the value of fuel per ton of sugar 

 amounts to 15.4 - 8.27 = 7.13 cwts. 

 adding to this the ... ... 3.77 „ 



