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X 



CHAPTER XX1Y. 



THE ASSAY OF SUGAR HOUSE PRODUCTS. 



Determination of Water and Total Solids. l. By Specific 

 Gravity. The connection between specific gravity and percentage of sugar in 

 solution has been very accurately worked out, and hence if the specific gravity 

 of a pure sugar solution be known the percentage of sugar is obtained by 

 reference to tables ; in actual sugar house work it is customary 

 to treat all bodies present in solution as having the same effect on 

 the density as has cane sugar; thus a juice of density 1-06566 is 

 of the same density as a 16 per cent, solution of sugar, and this 

 juice is conventionally returned as containing 16 per cent, apparent 

 total solids. This determination is usually made by taking the 

 density with a Erix hydrometer ; this instrument is graduated on 

 a sugar basis; that is to say, 16 Brix is indicated when the 

 hydrometer is immersed in a 1 6 per cent, solution of 

 sugar. The hydrometer consists of a glass instrument 

 of the shape shown in Fig. 259 ; on the hydrometer 

 being immersed in a liquid it will sink to a certain 

 point, dependent on the density of the liquid ; the 

 point where the level of the liquid cuts the stem of 

 the hydrometer gives on the scale the density of the 

 liquid. 



Owing to capillary attraction the liquid will rise 

 as much as one-eighth of an inch up the stem of the 

 hydrometer, Fig. 260 ; it is at the lower level that the 

 reading is to be taken. 



Westphal Balance. The Westphal balance may 

 also be used to obtain the specific gravity and 

 apparent total solids of a sugar solution, as also may the pycno- 

 meter ; these methods find no extended use in a sugar laboratory. 

 As the determination of total solids from density is itself only 

 approximate, there is no benefit obtained by a determination of 

 the specific gravity to an extra decimal, and a determination 

 by the hydrometer is in nearly every case of sufficient delicacy. 



Standards of Reference. The table connecting sucrose per 

 cent. (Brix ) and density usually found are referred to water at 

 IG ' 9 ' 1 7 -5 C. as unity ; the hydrometers in use are graduated either at 

 17'5 C. or else for use in the tropics at 27*5 C.; let a Brix spindle correct at 

 17-5 C. indicate 20 at 28 C. ; then from the table of corrections in the 



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