BOOK VIII 



A — Launder. B — Cross trough. C — Two spouts. D — Boxes. E — Plate. F — 



Grating. G — Shovels. H — Second cross trough. I — Strake. K — Wooden 



scrubber. L — Third cross trough. M — Launder. N — Three-toothed rake. 



and the water carries off the valueless sand into the creek. This method 

 ot washing is most advantageous, for four men can do the work of washing 

 in two boxes, while the last method, if doubled, requires six men, for it requires 

 two boys to throw the material to be washed on to the plate and to stir it 

 with iron shovels ; two more are required with wooden scrubbers to keep 

 stirring the sand, mixed with the tin-stone, under the plate, and to push it 

 toward the upper end of the box ; further, two foremen are required 

 to clean the tin-stone in the way I have described. In the place of a plate 

 full of holes, they now fix in the boxes a grating made of iron wire as 

 thick as the stalks of rye ; that these may not be depressed by the weight 

 and become bent, three iron bars support them, being laid crosswise under- 

 neath. To prevent the grating from being broken by the iron shovels with 

 which the material is stirred in washing, five or six iron rods are placed on 

 top in cross Unes, and are fixed to the box so that the shovels may rub them 

 instead of the grating ; for this reason the grating lasts longer than the 



