PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 757 



imedian screw, which carried the pulp upward through boxes, 

 while water was carried downward to exhaust the pulp. This 

 screw was afterwards used vertically by Hallette and Boucherie. 

 Elevators were tried in tubes, carrying beets upward, while water 

 ran in an opposite direction. The maceration with hot water in 

 closed vessels is carried on successfully in Scelovitz, Moravia, by 

 Mr. Eobert. Schuetzenbach proposed the maceration of dried 

 beet slices, which, upon exhaustion, give a more concentrated 

 liquor (18" B'e.) and enable the manufacturer to work aud use 

 his machinery duriug the summer months. The disadvantages of 

 this process are the expense for drying and the consequent des- 

 tructiou of some crystallizable sugar. 



The beet juice, no matter in which way produced, contains, 

 beside sugar, foreign substances which during the subsequent ope- 

 rations destroy the sugar partly, or prevent its crystallization. 

 The removal of these substance's is therefore of vital importance. 

 This is effected first by defecation. The juice, by whatever man- 

 ner obtained, runs at ouce into the "defecating pans," made of 

 copper with an outer iron shell. Between the latter and the bot- 

 tom of the pan steam is introduced, as soon as the bottom is 

 covered with juice, until the juice in the pan has a temperature of 

 175° to 190*^, F. The steam-gauge is then closed almost entirely 

 and milk of lime added, which is slowly heated to the boiling 

 point. At the first boiling up, the steam is completely shut off, 

 the lime being most effectual at this temperature. The addition 

 of lime produces flakes in the juice which rise to the toj), forming 

 a scum. If the proper amount of lime is added, this scum will 

 begin to move at 189*^, F.; if too much lime has been added at a 

 higher temperature, and at a lower one if too little lime has been 

 used. At this first wave-like motion the scum also grows denser 

 and darker. The juice below is clear, and may be withdrawn after 

 a few (15) minutes. The scum sinks to the bottom, whence, with 

 the sediment, amounting to 18-30 per cent, of the juice, it is run 

 off' into a bag filter. Here the juice slowly is separated, while 

 the thick scum is afterwards pressed in the bags, and so deprived 

 of its juice. The bags have to be washed as quick as emptied, 

 frequently, in diluted muriatic acid, to remove the lime. This 

 defecation changes the black color of the juice into yellow and 

 removes its turbidity. The lime unites with the organic acids as 

 well as the phosphoric and sulphuric present in the juice, remov- 

 ing them thus, while it decomposes albumen, legumine, extractive 



