METHODS FOR DETERMINING SUGAR. 17 



HYDRAULIC PRESS. 



In Plate I is shown a form of press that has been used successfully 

 for beet pressing by this laboratory. It consists of a hydraulic jack 

 B fastened to two pieces of I beam clamped together for the base. 

 Fastened to these clamps are two upright steel rods K, and to them 

 are fastened I beams with clamps to hold the head block A. Fitted 

 to the ram G of the jack is an iron box with lip E, also the bent rods 

 F and the platform D. To operate this press the porous cast-iron 

 pan / is placed in the box E. A square of jute cloth is then placed 

 in the pan, and the sample of beet cuttings poured into it. The edges 

 of the cloth are folded over and the plate J is placed on top. A jar 

 for receiving the juice is placed on the platform D, and by means of 

 the handle // the jack is jumped up against the head block A. When 

 the juice has stopped running, the release valve at is opened and the 

 ram quickly returns to place. The pan /can be slid out on the rods 

 Fj the press cake removed, and a new sample inserted. It is essential 

 to have a pressure gauge on the chamber of the jack, since in ana- 

 lyzing beets by this method the same pressure should be maintained 



throughout. 



DIRECT METHODS. 



In the direct methods the per cent of sugar is determined directly 

 on the beet. These methods may be classified according to the sol- 

 vent used for extraction, namely, water or alcohol, and these may be 

 again divided into extraction in the cold and with heat. So many 

 slight modifications of these different methods are known and used 

 that all of them can not be discussed; only statements of the repre- 

 sentative methods can be given. 



WATER METHODS. 

 COLD-WATER DIGESTION METHOD OF PELLET. 



Weigh the normal amount of beet cuttings, 26 or 26.048 grams, and 

 transfer to a large-mouth flask (C, frontispiece) with a mark at 200.6 

 cc. 1 Add 5 cc of basic lead acetate solution (see p. 13), shake, and 

 add water up to the shoulder of the flask. Mix the contents by 

 rotating in the hand, and allow to stand 25 minutes in order to expel 

 the air bubbles. Beat down the collected froth with an ether spray 

 and fill the flask to the mark with water. Then shake the contents 

 vigorously, placing the hand over the mouth of the flask, filter, and 

 polarize in a 200 or 400 mm tube after adding a drop of acetic acid. 



For this method it is necessary to have the finest divided pulp 

 possible and it is also advisable to have a pear-shaped flask instead 



i Numerous experiments have shown that the marc of the normal weight of average beets occupies about 



0. f> oc of sp;irr. 



4426 Bull. 14611 3 



