CHAPTER VI. 



EVAPORATION OF THE DEFECATED JUICE NECESSITY OF RAPID 



EVAPORATION, AND DESCRIPTION OF APPROPRIATE EVAPORATING 



VESSELS — CONCENTRATION OF SYRUP AT A LOW TEMPERATURE 



VACUUM PAN — GADDESDEN'S PAN. 



Having in last chapter described the most effectual 

 methods of defecation, the next part of the process is the 

 conversion of the defecated juice into a syrup of the 

 density of 27° or 30° Beaume, to which point the evapora- 

 tion may be carried on under the usual atmospheric 

 pressure, without injury to the sugar, provided that the 

 operation be performed rapidly. The vessels usually 

 employed for this purpose are not adapted for the success- 

 ful accomplishment of the end in view, not being of a 

 proper shape to ensure rapid evaporation of the water, and, 

 moreover, causing a great waste of fuel, by the heat being 

 to a considerable extent absorbed by the brickwork in 

 which the coppers are built. The form of the vessels 

 should be such, that a large surface can be exposed to the 

 direct action of the fire, and, at the same time, to have the 



portion so exposed constantly covered with liquor. For 



i 



