23 



EXHIBIT OF METHODS AND APPARATUS FOR THE ANALYSIS OF SUGAR 



BEETS. 



One of the most rapid processes (shown in the case mentioned) con- 

 sists in cutting out from each beet a small cylinder with an apparatus 

 similar to an apple corer. From this cylinder a portion is cut with 

 the Pellet parallel-bladed knife, the knives being so adjusted that 

 the piece removed will weigh an alliquot part of the normal weight of 

 sample arbitrarily adopted for the polariscope used. This sample 

 portion is reduced to a pulp by the Hanriot machine and washed into 

 a graduated flask. A small quantity of lead acetate solution is then 

 added and the mixture diluted with water to a definite volume, thor- 

 oughly mixed by shaking and filtered. A tube, closed with glass 

 disks at each end, is filled with the clear filtrate and placed in the 

 polariscope ; the percentage of sugar is then read directly upon the 

 scale. This method sacrifices accuracy to some extent, but gains in 

 rapidity by eliminating the use of a balance for determining the 

 quantity of beet pulp to be used for each analysis. 



There is also exhibited the Keil and Dolle boring rasp, which can be 

 used either for sampling beets for seed selection or for sampling the 

 beets at the factory receiving laboratory. The Pellet conical rasp, 

 suitable only for the latter purpose, is also shown. Small apparatus 

 for expressing juice from beet pulp for the analysis of beet juice for 

 the purpose of seed selection also form a part of the exhibit. 



Two polariscopes are shown: a small one for the analysis of sugar 

 beets for seed selection, and a larger one of one of the latest improved 

 models, with an incandescent electric lamp for illumination, used 

 when greater accuracy is required. An important accessory of the 

 polariscope is the Pellet continuous tube, which greatly increases the 

 number of sugar solutions which can be examined in the polariscope 

 in a given time. Both the methods and the instruments for the polari- 

 scopic determination of sugars have been greatly improved during 

 recent years, until at the present time results of the highest accuracy 

 can be obtained when the necessary precautions are observed. 

 Recently the influence of temperature on sugar determinations by 

 means of the polariscope has been carefully worked out by several 

 investigators, and tables of factors, prepared by means of which cor- 

 rections may readily be made for the slight errors necessarily intro- 

 duced by the varying temperature of the laboratory. 1 



For the encouragement of farmers to produce the richest beets pos- 

 sible in a given region, it has long been the practice in Europe and in 

 this country to vary the price paid the farmer according to the per- 

 centage of sugar in the beets. Formerly it was the practice in Europe 



1 See article by Harvey W. Wiley, On the Influence of Temperature on the Spe- 

 cific Rotation of Sucrose and Method of Correcting Readings of Compensating 

 Polariscopes therefor. Journal of the American Chemical Society, 1891, 21, 

 568-596. 



