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THE SEPARATION OP THE CRYSTALS.Sugar Driers.—Sugar driers are used to dry white plantation refinedsugars and also find a use in drying the rather low grade sugars resulting fromcrystallization in motion schemes. A view of a form of drier is shown inFig. 216 ; it consists of an inclined cylinder a a which is caused to revolveabout a longitudinal axis, power being received from a belt at the pulleysh; inside the cylinder are a number of shelves which throw the sugar aboutin passage; the wet sugar enters through the shoot c and leaves at d; hotair heated by passing over the steam heated coils at e passes through thecylinder and leaves at/ under the influence of a fan. In the Hawaiian islandsthe sugar occupies about five minutes in its passage through the apparatusand reaches a temperature of about 180° P., the moisture falling from about1 *5 per cent, to about -5 per cent.Druelle Say Process. 4 —However carefully the masseeuite isboiled, a certain amount of fine grain is formed which passes through the centrifugalmesh ; this process aims at recovering this loss through the agency offiltration; the molasses containing the fine grain are passed through filterpresses of conventional design, the cake of fine grain which forms in thepresses being dissolved in the thin juice.Experimental Study of Centrifugals.—The various questionsthat arise with regard to the treatment of masseeuite in the centrifugal havebeen carefully studied by Geerligs 5 . He determined first from actual factoryexperiments the yield in the same masseeuite when boiled to different degreesof concentration and found that although more sugar separates out in closeboiled than in more open boiled masseeuite, the yield in crystals is notaugmented, as more water is required to remove the more viscid molasses; onthe other hand, there is a limit to the amount of water which should be left;he found the best results were obtained when the true-water content was 8 per. cent, to 9 per cent., corresponding to an apparent water content of 5 per cent,to 7 per cent.He found too, that when impure masseeuites were cured hot, direct fromthe pan, practically the same amount of crystals was obtained as whencured cold, but that with pure masseeuites considerably more crystals were•obtained when cured cold. This result is "of course due to the sugar in theimpure masseeuite, when cooling, separating as small grain ; in the puremasseeuite of less viscidity, to the sugar separating on grain alreadypresent.As a general rule the amount of sugar present as crystals is very muchthe same in all first masseeuites of both high and low polarization, and it isthe form and shape of the crystals that control the yield in the centrifugal.This point is of such interest that the following table due to G-eerligs isreproduced hero, where it will be plainly seen on inspection that the purer38525