CHEMICAL SELECTION OF MOTHERS. 77 



variation of 5 per cent, in percentage of juice under 

 observation, not only with different beets, but with the 

 same varieties. Mothers should not only be rich in 

 sugar, but rich in juice. As a basis of comparison, it 

 is proposed to determine the sugar percentage by the 

 water method, then to repeat the experiments by the 

 A'iolette copper mode, and divide these results one by 

 the other. It is claimed that this calculation would 

 give an excellent idea of the juice percentage of the 

 beet examined. Furthermore, it is recommended to 

 give preference to those beets which give the highest 

 product when the per cent, of sugar is multiplied by 

 the per cent, of juice. Respecting this mode, it seems to 

 the writer that it would be too long and expensive for 

 root selecting, in seed growers' laboratories. 



4th. Estimation of Sugar in the Juice by Chemical 

 Methods.* All these methods require the sugar to be 

 transformed into glucose and the proportion of glucose 

 then determined b>- the use of a standard alkaline cop- 

 per solution. When all the copper has been reduced 

 by the glucose, the solution is no longer blue. Special 

 stress is placed on the weight of the oxide of 

 copper found, or even on the weight of cop- 

 per which has undergone a proper reduction. While 

 these methods were in vogue for the estimation 

 of sugar in the beet, they demanded too much 

 care and time for general use. Furthermore, they have 

 proved to be inaccurate in the hands of the average 

 chemist. In the selection of beets with the view to 



•The process of marmfacture would be TPry simple if juice con- 

 tained oiilT sugar, but there are many salts in dissolution, all of which 

 exert considerable influence on the ultimate crystallization. Hence, it 

 Is very important to know the proportion between sugar and total 

 solid substances ; this relation is known as the purity coefBcient. The 

 percent, of solid substances Is determined wltli a hydrometer. If a 

 juice contains 16 per cent, solid substances, of which U per cent, is 



sugar, then li>£l22= purity coefflcient=87.5. This should never be lower 



16 

 than 80, otherwise the working of such roots into sugar could not ba 

 made profitable. 



