686 



Popular Science Monthly 



Cleaning and Sorting Beans 

 by Machinery 



A MACHINE for dcaiiing and sorting 

 beans has been invented by D. E. 



Krause of Sobieska, Wisconsin. First, 



the beans are poured into a large hopper- 

 like receptacle. From this they are 



shaken down an inclined chute which has 



a wire screen 



as its bottom 



member. \ 



Under- 



sized beans, 



small stones 



and dirt drop 



through this 



screening and 



arethuselinii- 



nated. From 



this inclined 



chute the 



clean beans 



fall down on 



to an endless 



conveyer-belt. 



As the belt rolls along, the workman 



sitthig in front of it picks out any black 



or imperfect beans. 



The device makes it possible to clean 



and sort a large (luantity of beans 



in a remark- 

 ably short 

 time. It does 

 I li e work 

 thoroughly, 

 employing 

 onl\- one 

 man. 



The water and the electrolyte mix at the head of the 

 trough and in passing the hopper wash the sand down 



One workman using the machine i:in iUmh .nul soil a 

 large quantity of beans in a remarkably short time 



Electrical Extraction of Gold 

 from Black Sand 



THE black santi concentrates of the 

 placer and quartz mines in western 

 United States contain values in gold as 

 well as in other rare metals. A recent 

 invention based on electrolysis is now 

 being demonstrated in \arious localities 

 for the extraction 

 of the gold, which 

 often exceeds two 

 hundretl dol- 

 lars per ton. 

 The prin- 

 ciple involved 

 in the opera- 

 tion will be 

 unders tood 

 !)>■ reference 

 to the draw- 

 ing. Carbon 

 bars are 

 mounted in 

 slots in the 

 sides ol a 

 wooden trough twel\-e inches wide and 

 fit in depressions in the bottom of the 

 trough, these depressions containing a 

 quantity of mercury. 



The si>ace allowwl between the car- 

 bons and the surface of the mercury is 

 less than one-eighth of an inch. The 

 sand is placed in a hopper perforated at 

 its lower edge with a number of small 

 holes. The electroKie is stored in a 

 barrel. A pipe furnishes pure water, 

 which flows directly into the trough. 



In operation, the positive and negative 

 wires of an eight -%-olt generator arc 

 connected with the carbons and with 

 the mercury respectively. The 

 correct amounts of the electrolyte 

 and |)ure water are turned into 

 the trough. They mix at the 

 head </f the trough, and, in pass- 

 ing the hopper, gradually wash 

 the sand ilown the trough 

 through the space between the 

 carbons and mercury, where the 

 current, acting upon the gold, 

 deposits it in the mercury, with 

 which it .uu.ilgam.ites and from 

 which it is extractinl. 



Po all appear.mce the sand 

 undergoes no change whatever, 

 but an assay of the tailings 

 seldom gives a trace of the gold. 



