104 



NORTHERN SUGAR INDUSTRY. 



The polariscope containing the apparatus for converting ordinary into 

 polarized light ; device for analyzing the polarized ray and the divided 

 circle and vernier for measuring and reading the amount of rotation. 



Lamp for furnishing monochromatic light (a gas lamp furnished with 

 spoons of platinum which carry fragments of fused common salt). 



Pipettes for measuring the sugar solution. 



Hydrometer for determining specific gravity. 



The specific gravity having been determined it is easy to calculate 

 the weight of solution taken from the volume measured in the burette. 

 Thus if 10 cubic centimeters be measured the specific gravity of which 

 is 1.06, the total weight of the juice taken is 1.06x10=10.6 grams. 



The instrument figured in the cut is so adjusted that 16.19 grams 

 of pure sugar dissolved and made up to 100 cubic centimeters will read 

 100 on the scale. A fifteen cubic centimeter pipette should be used for 

 ordinary cane juices. This volume (15 cubic centimeters) wyi weigh 

 so nearly 16.19 grams that the difference uiay be neglected. 



By using a pipette in this way or a burette, no balance is required, 

 and thus a very expensive piece of apparatus is dispensed with. 



Burette for the more exact measurement of juice. 



Basic acetate of lead. This chemical is prepared by taking ordinary 

 sugar of lead and boiling a strong solution of it for some time with an 

 excess of litharge (oxide of lead). The solution is then filtered and 

 must be kept in a well-stoppered bottle. 



Funnels, filter-stands, and filter-papers. 



Flasks, graduated for making solutions up to standard volume. 



THE PROCESS. 



Measure out as nearly as possible 16.2 grams (or two or three times 

 that amount) into the 100 cubic centimeter flask. 



Add two or three cubic centimeters of the basic acetate of lead solu- 

 tion, and then fill up to the mark with pure water. 



Shake the flask well, holding the ball of the thumb on its mouth, and 

 filter into the tube of observation. When the tube is full, put on the 

 cap and place in the polariscope. Having adjusted the light, turn the 

 instrument until both halves of the field of vision are of the same tint. 

 In the monochromatic instrument, before adjustment one-half of the 

 field of vision will appear dark and the other yellow. 



The disk is now turned until both halves are equally illuminated. 

 In the other instrument one-half the field of vision will be blue and the 

 other rose-red. The adjustment is now made until both halves appear 

 alike. 



Through the small microscope which is focused on the vernier is now 

 read ofl' the number of divisions through which the analyzer has been 

 turned. This number is the percentage of sugar if 16.2 gms. of the orig- 

 inal juice have been taken. Otherwise it is to be divided by the num- 



