70 SUGAR BEET SEED. 



seed production, the Violette method had a very- 

 extended appHcation in many laboratories, and a 

 description of this mode is of special interest. 



Violette Method. 



This mode of analysis, like the Fiihling, is based 

 on the amount of copper reduced by glucose; the 

 sample taken from the beet is rather larger than is 

 actually required. The early sampler consisted of a 

 simple steel apple-corer; the direction given to the 

 appliance should be such as to meet the axis of the 

 beet at a point one-quarter* of its total length from the 

 crown of the root ; it may be perpendicular or slanting, 

 providing it passes through the centre corresponding 

 to k (Fig. 28). The sample should be sliced into small 

 pieces, precaution being taken to remove the 

 outer skin. 



These should be weighed. Exactly five grams of 

 these slices are carefully placed in a flask of 100 c. c. 

 (this weight and flask selection has many advocates); 

 to it are added 10 c. c. of normal sulphuric acid, then 

 40 to 50 c. c. of distilled water. The flask and con- 

 tents are gradually heated for 15 to 20 minutes, under 

 which circumstances, all the sugar of the sample is 

 converted into glucose; the liquid is allowed to cool 



*For matlieniatical reasoTiiTig of same, see "Ware on Sugar Beet,'* 

 Pagjes 181-182, wliich is as follows: Mr. Violette supposes the beet an 

 exact surface of revohition engendered by the triangle ABC (Fig 29), 

 and tbat the sngar contained increases in an arithmetical progression 

 from D to C. If LM be an infinitesimal cylinder parallel to the axis, 

 CD, according to the t.heory just mentioned the point S, middle of 

 XiM, will have an average amount of sugar for the small element 

 under consideration. The same argument will apply to O, when the 

 cylinder having the axis DC is considered. If Obe ioined to A and B, 

 evidently the lines OA and OB will be the line of all the averages of 

 small cylinders possible to imagine as existing in the interior of the 

 fceet, aiid the centres of OA and OB, or X and X', will represent the 

 exact position of the average of all the averages, and if each 

 horizontal slice contains the same amount of sugar, we could write, 



OY OX CD 



= =1. Then0Y=YD = 



YD XA 4 



Some German cheniists recommend that the sample be taken as shown 

 In the engraving. 



