342 



BOOK VIII. 



A — Sieve. B — Tub. C — Water flowing out of the bottom of it. 

 E — Three-toothed rake. F — Wooden scrubber. 



D — Strake. 



earth or sand is found on the slopes of mountains or hills, or in the level fields 

 which are either devoid of streams or into which a stream cannot be diverted, 

 miners have lately begun to employ the following method of washing, even 

 in the winter months. An open box is constructed of planks, about six 

 feet long, three feet wide, and two feet and one palm deep. At the upper 

 end on the inside, an iron plate three feet long and wide is fixed, at a depth 

 of one foot and a half from the top ; this plate is very full of holes, through 

 which tin-stone about the size of a pea can fall. A trough hewn from a tree 

 is placed under the box, and this trough is about twenty-four feet long and 

 three-quarters of a foot wide and deep ; very often three cross-boards are 

 placed in it, dividing it off into compartments, each one of which is lower 

 than the next. The turbid waters discharge into a setthng-pit. 



The metaUiferous material is sometimes found not very deep beneath 

 the surface of the earth, but sometimes so deep that it is necessary to drive 

 tunnels and sink shafts. It is transported to the washing-box in wheel- 

 barrows, and when the washers are about to begin they lay a small launder. 



