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Page:Popular Science Monthly Volume 89.djvu/700

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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.

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