44 SUGAR 



meets with fresh slices. Here the density of the juice 

 in the cells exceeds that of the weak sugar solution, 

 and diffusion goes on briskly. The process is con- 

 tinued through about half a dozen vessels. The solu- 

 tion of sugar when it has travelled so far is so nearly 

 of the same density as the juice in the cells, that diffusion 

 practically ceases. The sugar solution called diffusion 

 juice is, therefore, drawn off, and goes to a measuring 

 tank, and thence to the clarifiers to ' commence the 

 defecation process. We now have six vessels of the 

 diffusion battery of which it may be said roughly that 

 in the first the slices have lost nearly half their sugar, 

 in the second they may have lost about a quarter, 

 and so on up to the sixth where very little sugar has 

 been diffused out. 



When the weak sugar solution left the first vessel 

 fresh water was turned on, and followed in the round. 

 A fresh exhaustion of the slices results, the process will 

 finish at the seventh vessel, and again the contents 

 of a vesselful of diffusion juice will be measured and 

 go to the defecation. We can imagine the process 

 continued until the whole battery of vessels is at work. 

 The liquid is circulating under pressure the whole time, 

 but when the moment comes that the slices in No. 1 

 are exhausted ah 1 its connections are turned off, the 

 pressure is transferred to No. 2, the man-hole below 

 in No. 1 is opened and the exhausted slices are shot out 

 by means of compressed air. If the battery is circular 

 there is a pit in the centre towards which the opening 

 at the bottom of each vessel is directed, and which 

 receives the wet exhausted slices. That the slices 

 may be loosened, in order to be more easily ejected, 

 the last charge of water to that vessel is directed from 

 the bottom upwards. The vessel is at once refilled 

 with fresh slices, and becomes the last instead of the 



