Agricola, Georgius, De re metallica, 1912/1950

List of thumbnails

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            <p type="main">
              <s>
                <pb pagenum="309"/>
              it on each edge narrow strips, of no great thickness, and fix them to the beams
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              with nails. </s>
              <s>They agitate the metalliferous material with wooden scrubbers
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              and wash it in a similar way. </s>
              <s>As soon as little or no mud remains on the
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              canvas, but only concentrates or fine tin-stone, they lift one beam so that
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              the whole strake rests on the other, and dash it with water, which has been
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              drawn with buckets out of the small tank, and in this way all the sediment
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              which clings to the canvas falls into the trough placed underneath. </s>
              <s>This
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              trough is hewn out of a tree and placed in a ditch dug in the ground; the
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              interior of the trough is a foot wide at the top, but narrower in the bottom,
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              because it is rounded out. </s>
              <s>In the middle of this trough they put a cross­
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              board, in order that the fairly large particles of concentrates or fairly large­
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              sized tin-stone may remain in the forepart into which they have fallen, and
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              the fine concentrates or fine tin-stone in the lower part, for the water flows
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              from one into the other, and at last flows down through an opening into the
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              pit. </s>
              <s>As for the fairly large-sized concentrates or tin-stone which have been
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              removed from the trough, they are washed again on the ordinary strake. </s>
            </p>
            <figure number="171"/>
            <p type="caption">
              <s>A—CANVAS STRAKE. B—MAN DASHING WATER ON THE CANVAS. C—BUCKET.
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              D—BUCKET OF ANOTHER KIND. E—MAN REMOVING CONCENTRATES OR TIN-STONE
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              FROM THE TROUGH.</s>
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