EXTRACTION OF SUGAR FROM BEETS. 331 



The conversion of the juice into sirup should be done 

 as speedily as possible ; for when evaporation is slow the 

 liquor becomes pasty, as part of the sugar is decomposed 

 and passes to the state of molasses, and the difficulty of 

 boiling is increased. It is necessary then that evaporation 

 should be carried on with violent boiling, and for this rea- 

 son the boilers made use of should be broad and shallow, 

 so as not to heat only layers of the liquor, and in order 

 that ebullition may tak« place at once through the whole 

 mass of the liquid ; the furnaces likewise should be so 

 built as to heat the boilers equally. The evaporation of 

 422 gallons should be completed in four hours. 



The operation is known to be good, and the juice to have 

 been well prepared, when ebullition takes place without 

 causing the liquor to swell and blister ; when there ap- 

 pears on the surface only a brownish foam, the bubbles of 

 which disappear immediately upon being pressed with a 

 spoon, and when a dry sound is produced by striking upon 

 the liquor. 



If, on the contrary, there forms a whitish, gluey foam, 

 which does not subside, the operation is bad ; evaporation 

 requires a long time, and the boiling is difficult. In this case 

 a little butter is, from time to time, thrown upon the sur- 

 face to quiet the effervescence ; the quantity of animal 

 charcoal is increased, and the fire is checked. All these 

 palliatives, however, do not correct the radical fault, and 

 such appearances always presage bad results. 



ARTICLE VI. 

 On Boiling the Sirup. 



The sirups prepared over night are the next day dried 

 to extract the sugar from them. 



The products of two operations upon 5000 beets are 

 mixed together in a boiler, whence they are taken to form 

 four successive dryings or boilings. One fourth part of 

 these sirups is thrown into a round boiler, forty inches in 

 diameter and twenty in depth ; under this a fire is kindled ; 

 the liquor is made to boil, and the boiling continued till the 

 operation is ended. 



