STJGAR, 



159 



each drop of lime added, until they become extinct, and the super- 

 natant liquor perfectly transparent ; this is the precise point at 

 which the liquor is tempered, and each drop of lime added after 

 this, causes the flakes to diminish rapidly in size, at last entirely 

 to disappear (being re-dissolved), and the liquor to resume its former 

 gummy appearance ; it is, therefore, evident that there should be 

 no such expressions as tempering high or low. 



The reason why some liquor is so difficult to clean is, that it is 

 either tempered high or low ; if it be exactly tempered, the im- 

 purities contained in it being entirely separated and thrown out 

 of solution, rise to the surface immediately on the application of 

 heat, and are easily removed ; but if there be too little Kme, a great 

 portion remains in solution, and if too much, a proportional 

 quantity is re-dissolved ; and in either case cannot be removed by 

 any mechanical means. It is, therefore, necessary to have some 

 precise test for the application of lime. 



As regards the superiority of the hot over the cold tempering, let 

 any one take, in separate vessels, two gallons of cane-juice, and 

 temper one, adding the lime in small quantities — say, of three 

 grams at a time — and keeping an account of the quantity used ; 

 he will find that the first portions produce no efi"ect whatever, and 

 that it is only after the addition of a considerable quantity that the 

 desired precipitation of the impurities manifest itself Why is 

 this ? Because albumen, gluten, resin, and chlorophyle, being 

 soluble in lime, lime is equally so in them, and they must first be 

 saturated before it will produce any other effect. Let the liquor 

 thus tempered, be then placed on one side. Put the other gallon 

 over a fire, and boil it, removing the scum just before, and during 

 ebullition ; let it then be taken off" the fire, and tempered in the 

 same way as the other. The very first quantity of lime added 

 causes the appearance of the floccy precipitate ; and if the addition 

 of the lime be continued until it be precisely tempered, it will be 

 found that the hot possesses the following advantages over the 

 cold-tempered liquor : — In a quarter of an hour its impurities will 

 have subsided to a sixteenth of its bulk, leaving the supernatant 

 liquor as bright and clear as pale brandy ; while those in the other 

 have only sunk to one-quarter of its bulk. The color of the 

 former clear liquor will not be less than one-half the intensity of 

 that of the latter. The lime used in the hot has been less by one- 

 third than the quantity used in the cold tempering. 



Of course, on level estates there is little difficulty in tempering 

 liquor, but on hilly properties scarcely two pans will require the 

 same quantity. 



It is generally believed that the object of adding lime to cane- 

 juice is for the purpose of neutralising an acid, and it is to the 

 reception of this fallacious idea that it is indebted for its 

 long and continued use, and the present backward state of sugar 

 manufacture is attributable : I unhesitatingly assert that, if there 

 be an acid present in the cane-juice, the addition of lime to it will 

 be injurious instead of beneficial. There are only four acids that 



