19 



is allowed to remain until thoroughly cool. The time required for 

 distillation, as already stated, varies from twenty to thirty hours and 

 averages about twenty-four hours. The distillate from the retorts 

 passes to the condensers (figs. 5 and 7), where the acid, alcohol, and 

 other valuable constituents are condensed to liquid form and then 

 carried to a large wooden settling tank, which may be either under- 



FIG. 11-. Plan of a refining apparatus: A 1-2, raw liquor vats; B 1-6, raw liquor settling tanks; C 1, 

 tar still; C 2-3, raw liquor stills; D 1-2, neutralizing vats; E 1-3, lime-lee stills; F 1-3, alcohol 

 stills; G, weak alcohol storage tank; H, strong alcohol storage tank. 



ground or overhead, where it is allowed to stand for several days in 

 order that the tar may settle. The uncondensed gases pass from the 

 condensers to the gas mains (figs. 5 and 10) and are either carried 

 directly to the furnace and burned there or go to a gas holder, from 

 which they are used. If the tar is not otherwise treated it is blown 

 under the boilers with a steam jet and burned. Figures 10, 11, and 



[Cir. 86] 



