CANE SUGAK. 



that of the sugar present is pressed in a towel, placed in the flask, the 

 contents of the flask well stirred and kept at 55C. for four hours ; clarification 

 is effected by alumina cream, and the whole, after making up to 100 c.c., 

 filtered and polarized. 



In all modifications of the official Clerget process it must be remembered 

 that a constant differing from the official one obtains, and that must be 

 determined experimentally under the same conditions as those under which an 

 analysis is made. 



The Separation of Sugars occurring in Mixtures. The 



estimation of cane sugar in the presence of levulose and of dextrose is 

 performed under the Clerget process ; the estimation and separation of the 

 accompanying reducing sugars is thus obtained after Browne 24 : 



1. The reducing power of the sugars is expressed in terms of dextrose, 

 the reducing power of which is put equal to unity. The reducing power of 

 the commoner sugars investigated by Browne is given in Chapter XXIII. 



2. The optical rotation of the sugars is expressed in terms of cane 

 sugar, the rotation of which is put equal to unity. According to Browne 2 

 these are 



Cane Sugar 1-000 



Dextrose .. .... -793 



Galactose.. .. .'.-.. .. 1-21 



Arabinoso . 1-571 



Xylose .". .. '283 



Levulose. The rotation varies so much with temperature that special 

 numbers have to be calculated for each temperature. The factors calculated 

 from the formula of Jungfleisch and Grimbert 20 are 



Temper- Concentration, 



ature. 1 per cent. 2 per cent. 3 per cent. 4 per cent. 5 per cent. 10 per cent. 25 per cent. 



15 .. 1-384 .. 1-385 ..1-387 ..1-389 ..1-390 ..1-398 ..1-422 



20 . . 1-341 . . 1-343 . .1-345 . .1-346 . . 1-348 . .1'356 . .1-380 



25 .. 1-299 .. 1-301 ..1-303 .. 1-304 .. 1-306 .. 1-314 ..1-338 



30 .. 1-257 .. 1-259 .. 1-261 ..-1'262 .. 1-264 . 1*272 ..1-296 



Let x =. per cent, of a given sugar A. 



Let y = per cent, of a given sugar B. 



Let a = dextrose ratio of sugar A. 



Let I =. dextrose ratio of sugar B. 



Let R =. per cent, of reducing sugars as dextrose. 



Then oc + by = J2 (1) 



Let a polarization factor of sugar A. 

 Let /3 = polarization factor of sugar B. 



Let P = polarization of mixture, i.e., reading in Yentzke scale in 20 cm. 

 tube for 26 grms. of sugar in 100 c.c. 



Then ax + fry = P (2) 



Solving these two equations the amounts of the sugars are found. 



456 



