344 CHYMISTRY APPLIED TO AGRICULTURE. 



colored below ; I complete the bleaching by a slight clay- 

 ing, applying the earth immediately to the surface of the 

 loaves without any intermediate layer of sugar. 



I find that bleaching is performed more speedily and 

 with less labor in this way ; the evils arising from the use 

 of sirup alone are obviated, and but a small portion of 

 sugar already bleached is dissolved. 



In order to appreciate all the advantages arising from 

 well-conducted operations, it is necessary that one should 

 know the change produced in sugar by repeated meltings ; 

 it is brought first to a point when it will no longer crystal- 

 lize, and afterwards to the state of molasses. Sugar which 

 has been three or four times boiled over, will still crystal- 

 lize upon the sides of the moulds, but the middle of the 

 loaf will be only a uniform, thick, white mass, destitute of 

 the agreeable taste of sugar ; this substance, if melted, does 

 not again become solid, but remains in the state of mo- 

 lasses. 



I ought to mention, that in the various operations that 

 are performed upon sugar, the nature of the substance is 

 often made to undergo a series of changes or a succession of 

 degenerations equally constant and regular. 



I have just mentioned that when sugar is made to re- 

 pass two or three times through the boiler, it is rendered 

 uncrystallizable, and the middle of the loaf is found to 

 consist of a uniform mass of the consistency of butter, 

 not possessing the agreeable flavor of crystallized sugar. 

 This mass, dissolved in water and concentrated by- heat, 

 is reduced to molasses; and when the evaporation and 

 clarification of the juice of beets is prolonged beyond a 

 certain time, nearly all the sugar is reduced to molasses, 

 and the boiling is rendered long and difficult ; when this 

 is the case, the sirup throws up an abundance of adhe- 

 sive white foam, which, when removed with a skimmer, 

 thickens and presents all the characteristics of vegetable 

 wax. The experience of twelve years has uniformly fur- 

 nished me with these results. 



I am thoroughly convinced that these alterations would 

 be avoided by evaporating the sirup in a vacuum ; it has 

 even occurred to me that the animal charcoal produced 

 good effects only by its opposing the action of the oxygen 

 of the atmosphere upon the sugar, since nearly the same 

 results are obtained by the use of butter and other oily 

 substances susceptible of extreme division. The secret of 



