WUSTERHAGEN* DRYER. 109 



be entirely burned while the other would be only semi-dried. 

 Long observations had demonstrated that the best mode is to 

 begin with a systematic cleaning, then an air reduction in weight 

 followed by drying. The tops remain upon the ground for 

 several weeks; then they are put into small piles where the 

 wilting continues, after which they are taken to the hot air 

 dryer. By this treatment the oxalic acid is almost entirely de- 

 stroyed, while the sugar contained in the tops has undergone 

 very little transformation. The drying of the leaves and tops 

 is then continued at a lower temperature, so that there can be 

 no possible danger of caramelization, a special system for regu- 

 lating the temperature of the dryer being used. The reduction 

 in weight of the tops and leaves always means a considerable 

 loss during sifting of the dust, impurities, etc. At the start 88 

 per cent, of substance to be dried diminishes at least 20 to 30 

 per cent, in weight during the air-drying or wilting. The arti- 

 ficial drying means 30 to 48 additional percentage. The leaves 

 finally retain about 15 per cent, moisture. Beet leaf drying 

 has already obtained considerable proportions. 



According to Petry & Kecking, who have introduced the 

 Wusterhagen mode upon several farms, these dried leaves will 

 keep for at least two years under ordinary conditions, notwith- 

 standing the fact that they show certain hygrometric powers. 

 A sample containing 20 per cent, of water did not mildew even 

 after a long period of keeping. They declare that this keeping 

 power is due to their sugar percentage. 



Proebent's experiments in beet* leaf drying have shown that 

 the operation costs about 50 cents for 220 Ibs. dry matter. In 

 Belgium the profits are about one cent a pound. From a 

 hectare (2.5 acres) there is collected about 3 tons of dry sub- 

 stance, which is worth at least 830 in its dried state. 



Vibrans cannot understand how the technical authorities can 

 possibly attempt to extract the water from a substance which 

 contains already less moisture than do pressed diffusion cos- 

 settes, and if these can be dried under remunerative conditions 

 certainly beet leaves could be desiccated under very much better 

 circumstances, if, instead of pressing the product, some practical 

 method was devised for bringing the dryers to the leaves as 

 found upon the field. 



