. MANUAL FOR SUGAR GROWERS. 



135 



as to retain a tliin film of moisture on the surface 

 of each disc ; the wash in its downward course over 



jUOUTtET FDR EXHAUSTED WASH 



Fig. 20.— Diagram of continuous still. 



the perforated discs meets the ascending hot va- 

 pours generated by means of steam admitted from 

 a steam-boiler not shown in the figure. The more 

 volatile portion of the wash — the alcohol — escapes 

 through the pipe into the worm of the condenser, 

 where it is condensed as already described. The 

 less volatile portion passes downward into the cham- 

 ber at the bottom of the rectifying-column, whence 

 it is run off as it accumulates. 



The exhausted residue from which the spirit has 

 been distilled is known as dunder. It contains vari- 

 ous mineral matters, as potash, phosphoric acid, etc., 

 together with any sugar which has escaped fermen- 

 tation. A certain quantity of it is usually employed, 

 instead of water, in setting up fresh wash for fer- 

 mentation, the unfermented sugar being thus saved, 



