84 SUGAR BEET SEED. 



use it, with the view of a comparatively rapid method 

 of comparison for sugar estimation, remembering never 

 to examine the color of the solution by holding it up to 

 the light, but, on the contrary, against a white wall; 

 the colors due to refraction, etc., are thus avoided. 



5th. Estimation of the Sugar in the Beet by 

 Means of the Polariscope(o) Alcohol Method. — Among 

 the first to introduce alcohol in the laborato- 

 ries for sugar estimation was Scheibler (1878). 

 However, one must go back to 1762, when Margraff 

 gives the first description of how he boiled alcohol with 

 dried slices of beet, and the filtrate was subsequently 

 left to crystallize during several weeks and the product 

 obtained was again washed in alcohol, etc. From 

 one-half pound of beets he got half an ounce of sugar. 

 Then, in 1825, Dubrunfaut introduces another method 

 which did not differ from Margraff's in its essen- 

 tial workings. 



In the Peligot process, alcohol at 90 degrees was 

 used, and from this time on also by Payen, Scheibler 

 and Soxhlet. The digestion by cold alcohol, as used by 

 Stammer, the cold-alcohol process, has still many advo- 

 cates in Germany. In beet selection laboratories the 

 alcohol need not be stronger than 80 to 85 degrees. 

 This later was changed to a hot-alcohol process. The 

 various appliances having alcohol as a basis are too 

 numerous to mention. However, certain selecting 

 laboratories use them, not for general selection, but 

 as a final determination, of sugar percentage for beets 

 in cases where the roots are shown to be of very supe- 

 rior quality, by previous methods. A certain number 

 of such beets of each classification are sent to the sec- 

 ond laboratory to undergo a second analysis. From 

 the results there obtained it is possible to determine to 

 which series the mother belongs. The per cent, of 

 sugar by the first test does not, however, appear on the 

 said list, so that the second chemist can have no pos- 



