9 



The Scheibler method, as above described, differs from the original only in a few minor 

 details, especially in the arrangement of the extraction apparatus. The Soxhlet extraction 

 apparatus is much more effective than Scheibler's original instrument. 



(6) Pellet's aqueous method Hot digestion. Any good rasp may be used in the prepara- 

 tion of the pulp for this method. The special flasks with enlarged necks are convenient 

 for use in this method. Transfer 26.048 grams of the pulp to the flask, using a little water 

 to wash the weighing capsule and funnel; or, for the Laurent, employ 32.58 grams of pulp, 

 i. e., 2 X normal weight. The flasks are graduated to contain 201.35 cc for the Schmidt 

 and Haensch and 201.7 cc for the Laurent polariscopes, in order to compensate for the 

 volume of the marc and the lead precipitate. Add 5 to 10 cc subacetate of lead solution 

 of 54.3 Brix f r the clarification. Approximately 6 to 7 cc are required per 26 grams 

 of beet pulp. This reagent should be run into the flask in advance of the beet pulp. Add 

 a few drops of ether to beat down the foam, then sufficient water to increase the volume 

 of the solution to about 190 cc. Heat to 80 C. in a water bath and maintain this tempera- 

 ture about thirty minutes, occasionally giving the flask a circular movement to facilitate 

 the escape of the air from the pulp. Increase the volume of the solution from time to time 

 during the heating, so that when the operation is completed only a few drops of water will 

 be required to complete the volume of the solution to the mark. After approximately 

 thirty minutes' heating, cool the flask and contents and add strong acetic acid to the solu- 

 tion to acidity, dilute to the graduation, mix, and filter. The state of division of the pulp 

 will govern the time of heating. In polarizing the filtrate, use a 400-mm observation 

 tube, thus directly obtaining the per cent sucrose in the beet with the Schmidt and Haensch 

 polariscope, or double this percentage if the Laurent instrument be used. 



Add the methods selected by the international committee for unify- 

 ing methods of sugar analysis, as provisional methods of this associa- 

 tion. These methods are as follows: 



1. In general, all sugar tests shall be made at 20 C. 



2. The graduation of the saccharimeter shall be made at 20 C. Twenty-six grams of 

 pure sugar, dissolved in water, and the volume made up to 100 metric cc, or during the period 

 of transition 26.048 grams of pure sugar in 100 Mohr cc, all weighings to be made in air 

 with brass weights, the completion of the volume and the polarizations to be made at 20 

 on an instrument graduated at 20 should give an indication of 100 on the scale of the 

 saccharimeter. For countries where temperatures are usually higher than 20 C., it is 

 permissible that saccharimeters be graduated at 30, or any other suitable temperature, 

 under the conditions specified above, providing that the analysis of the sugar be made at 

 the same temperature that is, that the volume be completed and the polarizations made 

 at the temperature specified. 



3. Preparation of pure sugar: Purest commercial sugar is to be further purified in the 

 following manner: A hot saturated aqueous solution is prepared and the sugar precipitated 

 with absolute ethyl alcohol; the sugar is carefully spun in a small centrifugal machine 

 and washed in the latter with absolute alcohol. The sugar thus obtained is redissolved in 

 water, the saturated solution again precipitated with alcohol and washed as above. The 

 product of the second crop of crystals is dried between blotting paper and preserved in glass 

 vessels for use. The moisture still contained in the sugar is determined and taken into 

 account when weighing the sugar which is to be used. 



The committee further decided that central stations shall be designated in each country 

 which are to be charged with the preparation and distribution of chemically pure sugar. 

 Wherever this arrangement is not feasible, quartz plates, the values of which have been 

 determined by means of chemically pure sugar, shall serve for the control of the saccha- 

 rimeters. The committee further decided that the above control of quartz plates by means 

 of chemically pure sugar should, as a rule, apply only to the central stations which are to 

 test the correctness of saccharimeters; for those who execute commercial analyses, the 

 repeated control of the instruments is to be accomplished, now as before, by quartz plates. 

 30625 No. 3006 2 



