CANE SUGAR. 



this, the density determinations and sampling can be done without spilling 

 juice about the laboratory, and the whole apparatus easily kept sweet and 

 clean. 



Purity. The purity of a sugar product is the percentage of sugar on 

 total solids ; when the total solids are estimated from the density or degree 

 Brix, the term apparent purity is used as distinguished from true purity when 

 the total solids are determined by drying. 



Sugar. The determination of the sugar in the juice is carried out in 

 actual practice as follows: A flask with two graduation marks, one at 

 100 c.c. and the other at 110 c.c., is filled to the 100 c.c. mark with 

 the sample of juice under analysis ; 6 or 7 c.c. of a solution of basic lead 

 acetate of density 1*25 are then added and the whole made up to 110 c.c. by 

 the addition of water. The flask and contents are then violently shaken and 

 filtered through a dry filter into a narrow cylinder ; those sold by dealers as 

 hydrometer immersion tubes, about six inches in height and one inch in 

 diameter, serve admirably ; the funnel which holds the filter paper may con- 

 veniently be stemless and rest on the rim of the receiving glass so as to prevent 

 evaporation. After sufficient of the juice has been filtered, a 20 cm. polaris- 

 cope tube is filled with the filtrate which must be perfectly clear and bright, 

 the polariscope tube closed, placed in the trough of the polariscope and the 

 reading observed. If JVbe the normal weight for the polariscope and R be the 



l * l 

 reading, the sugar in the juice as grms. per 100 c.c. is --- ; the pounds 



per gallon, as it is general to express results in many English factories, are 

 one-tenth of this result ; the percentage of sugar is obtained by dividing the 

 grms. per 100 c.c. by the specific gravity. This routine can, of course, be 

 varied ; the normal weight of cane juice may be weighed out, a sufficiency 

 of lead acetate added, the whole made up to 100 c.c., filtered and polarized; 

 the reading in the polariscope will now give directly the percentage of sugar 

 in the juice. Spencer's pipette is a convenient instrument for obtaining the 

 normal weight of a cane juice without the use of the balance; the upper stem 

 of an ordinary pipette is graduated with numbers corresponding to tenths of a 

 degree Brix ; when the pipette is filled to one of these marks the weight of 

 liquid delivered is a multiple of the normal weight for juice of that particular 

 degree Brix; for polariscopes which have a normal weight of 26-048 grms. 

 these pipettes deliver twice, and for those whose normal weight is 16-19 grms. 

 three times, the normal weight of juice. The polariscope reading (after making 

 up to 100 c.c.) divided by two or three, as the case may be, gives the percent- 

 age of sugar in the juice. 



Determination of Nitrogenous Bodies. The determination 

 of the nitrogenous bodies in cane juice is chiefly of interest to the agricul- 

 tural side of a sugar estate ; it forms, however, a means of testing the 



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