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 impurities 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 lime, 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 grains at a time—­and keeping an account of the quantity used; he will find that the first portions produce no effect 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 we could expect to find in cane juice—­mucous, saccholactic or saclactic, oxalic, and acetic acids.  The three first named of these, however, have never been traced, even in the most minute quantities; and if the latter be present, which, unfortunately, is