CANE SUGAR. 



for quartz wedge compensating instruments, the corre ction including that 

 known as Jobin's. 



True polarization (1 + -00039Q observed polarization, 

 where t is the difference between the temperature of observation and that at 

 which the instrument was graduated in C. 



This result is in very close agreement with those obtained by Harrison 

 and by Wiley. 



The rotation of levulose falls very rapidly with temperature rise. Honig 

 and Jesser 17 give for p = 9 and t = 13C. to 40C. 



[a] J = 103-92 + -671* 

 and for p 23-5 and t 9C. to 45C., 



[a] * =107-65+ -692* 

 Jungfleisch and Grimbert 20 combine temperature and concentration in the one 



formula 



[a] * = [101-38 -56* + -108 (c 10)] 



e being the concentration in grms. per 100 cc. 



There do not appear to be any results published connecting the 

 temperature and rotation of dextrose. 



The Effect of Inactive Bodies on the Rotation of 

 Sugars. A small decrease in the rotation of cane sugar is brought about by 

 the simultaneous presence of any of the following bodies : 



Hydrates of the alkalies and alkaline earths. 



Chlorides, nitrates, sulphates, carbonates, phosphates, acetates and citrates 

 of the alkalies. 



Eorax, magnesium sulphate. 



Chlorides of the alkaline earths. 



An increase is observed with formaldehyde. 21 



In the quantities in which these bodies occur in routine analyses the effect 

 is very small. 



In the presence of lead acetate the specific rotation of levulose decreases 

 until it becomes dextro-rotatory, and in the presence of mineral acids it 

 increases (v. Clerget Process). 



Bl-rotation. The initial rotation of many of the sugars when freshly 

 prepared is much higher than that after standing some time. After standing 

 24 hours a constant end rotation is obtained ; it is also rapidly obtained on 

 heating, and by the addition of certain bodies in minute proportion, e.g., 

 ammonia. 



452 



