BOOK VIII.

345

WM i

fmim,

&«

M(p!J

1=5®^

mm

ib

\'<y/&k

£sm

m vim

A —Launder. B —Cross trough. C—Two spouts. D —Boxes. E —Plate. F—Grating. G— Shovels. H —Second cross trough. I —Strake. K —Woodenscrubber. L —Third cross trough. M —Launder. N —Three-toothed rake.

and the water carries off the valueless sand into the creek. This methodof washing is most advantageous, for four men can do the work of washingin two boxes, while the last method, if doubled, requires six men, for it requirestwo boys to throw the material to be washed on to the plate and to stir itwith iron shovels ; two more are required with wooden scrubbers to keepstirring the sand, mixed with the tin-stone, under the plate, and to push ittoward the upper end of the box ; further, two foremen are requiredto clean the tin-stone in the way I have described. In the place of a platefull of holes, they now fix in the boxes a grating made of iron wire asthick as the stalks of rye ; that these may not be depressed by the weightand become bent, three iron bars support them, being laid crosswise under-neath. To prevent the grating from being broken by the iron shovels withwhich the material is stirred in washing, five or six iron rods are placed ontop in cross lines, and are fixed to the box so that the shovels may rub theminstead of the grating ; for this reason the grating lasts longer than the