182 THE SUGAR BEET. 



de Lille, he having proved that the portion of the 

 root containing the average amount of sugar is situated 

 one-fourth the distance from the neck, and it is in this 

 direction that the so-called apple-corer is directed/ 



The disadvantage of the chemical test is that it re- 

 quires much skill to obtain accurate results. The 

 methods of selection that we have thus far mentioned 

 have supposed beets rich in sugar at our disposal. 

 This is frequently not the case, as seeds that have been 

 bought and planted as being of the best, are of a poor 

 quality, or sufficient experience has been wanting in 



If O be joined to A and B, evidently the lines A and B will represent the 



line of all the averages corresponding to the small cylinders that it is possible 



to imagine as existing in the interior of the beet, and the centres of ^ and 



OB, or X and X' will represent the exact portion of the average of all the 



averages, and, if each horizontal slice contains the same amount of sugar, we 



OY OX CD 



could then write -jTj^ = -y-i == 1, then 0Y= YD^ —r . 



' The cylindrical portion obtained is divided into small slices ; five gr. of 

 which are placed in a receiver having a capacity of 100 c. c. ; to this is added 

 50 c. c. of water and 10 c. c. of sulphuric acid, the total is boiled, after which 

 10 c. c. of a caustic liquor is added ; this is permitted to cool, and the remain- 

 ing filled with water and filtered. One of Dr. Ures's burettes can be made 

 use of, and is filled with the above, then 10 c. c. of Barreswill's " cupro-potas- 

 sic" liquor is boiled in a testing-tube; in this the sugar solution is allowed 

 to drop as rapidly as possible until the blue color is nearly gone ; after some 

 few minutes several more drops are added, and a brown precipitate will form, 

 which afterwards turns red. If the liquor has still a bluish tint, it will be 

 important to add a few more drops, and the test is at an end, when these will 

 no longer give a brownish tint. The number of -centimetre cubes of the sugar 

 solution utilized being known, the calculation of the exact amount of sugar 

 that could be extracted from similar beets is a simple rule of three. 



