substance, which becomes, to a large extent, insoluble, and is re- 

 moved with the scum, what remains in the solution having no 

 effect whatever on the cane sugar. But here we meet with 

 another difficulty. If more lime than is necessary to neutralize 

 the acid has been added, although the excess has no effect what- 

 ever on the cane sugar, it will at once begin to decompose the 

 glucose, changing it into a series of very dark and bitter products, 

 which will impart a dark color, and a bitter, burnt taste to the 

 -syrup. Fortunately we are in the possession of a very simple 

 test which tells when lime enough has been added. If a piece of 

 blue litmus paper is dipped into water containing a small quantity 

 of acid, it at once turns red ; and if a piece of red litmus paper 

 is dipped into water made slightly alkaline by the addition of a 

 little lime water, it at once turns blue. If, now, to a portion of 

 the acidified water we add gradually some lime water, we will 

 soon arrive at a point when the solution will have no effect on 

 the color of either red or blue litmus ; in other words, it is 

 neither alkaline nor acid, but neutral. This will be treated of 

 again under the head of defecation. 



FERMENTATION". 



The next thing which tends to destroy the cane sugar is fer- 

 mentation. This process begins almost immediately after the 

 juice leaves the mill, and when the weather is warm large quan- 

 tities of sugar are lost in this way. Fermentation is at once 

 arrested by heating the juice to near the boiling point. Cane 

 juice should therefore never be allowed to remain standing any 

 length of time, but should be defecated as soon as possible after 

 coming from the mill. 



HIGH TEMPERATURE. 



High and prolonged heat is very destructive to crystallizable 

 cane sugar. At first the temperature will not vary much from 

 that of boiling water, or 212° F., but as it becomes more and 

 more concentrated the boiling point gradually rises, until, when the 

 syrup is thick enough for sugar making, the boiling point is from 

 232° to 234°. The destruction of sugar takes place long before 

 this point is reached. To 'get the best results the syrup should 

 not be boiled in an open pan after it reaches a density of 20" B., 



