Agricola, Georgius, De re metallica, 1912/1950

Table of figures

< >
[Figure 191]
Page: 372
[Figure 192]
Page: 373
[Figure 193]
Page: 374
[Figure 194]
Page: 375
[Figure 195]
Page: 376
[Figure 196]
Page: 378
[Figure 197]
Page: 379
[Figure 198]
Page: 380
[Figure 199]
Page: 381
[Figure 200]
Page: 383
[Figure 201]
Page: 384
[Figure 202]
Page: 385
[Figure 203]
Page: 386
[Figure 204]
Page: 387
[Figure 205]
Page: 388
[Figure 206]
Page: 389
[Figure 207]
Page: 390
[Figure 208]
Page: 395
[Figure 209]
Page: 396
[Figure 210]
Page: 397
[Figure 211]
Page: 399
[Figure 212]
Page: 403
[Figure 213]
Page: 406
[Figure 214]
Page: 408
[Figure 215]
Page: 410
[Figure 216]
Page: 411
[Figure 217]
Page: 412
[Figure 218]
Page: 413
[Figure 219]
Page: 415
[Figure 220]
Page: 421
< >
page |< < of 679 > >|
    <archimedes>
      <text>
        <body>
          <chap>
            <p type="caption">
              <s>
                <pb pagenum="339"/>
              with an iron shovel and agitated hither and thither in the water, until the
                <lb/>
              sand flows away and only the tin-stone remains on the shovel. </s>
              <s>The tin­
                <lb/>
              stone is all collected together and washed again in a trough by pushing it
                <lb/>
              up and turning it over with a wooden trowel, in order that the remaining
                <lb/>
              sand may separate from it. </s>
              <s>Afterward they return to their task, which they
                <lb/>
              continue until the metalliferous material is exhausted, or until the water can
                <lb/>
              no longer be diverted into the ditches.</s>
            </p>
            <p type="main">
              <s>The trough which I mentioned is hewn out of the trunk of a tree and the
                <lb/>
              interior is five feet long, three-quarters of a foot deep, and six digits wide.
                <lb/>
              </s>
              <s>It is placed on an incline and under it is put a tub which contains interwoven
                <lb/>
              fir twigs, or else another trough is put under it, the interior of which is three
                <lb/>
              feet long and one foot wide and deep; the fine tin-stone, which has run out
                <lb/>
              with the water, settles in the bottom. </s>
              <s>Some people, in place of a trough,
                <lb/>
              put a square launder underneath, and in like manner they wash the tin­
                <lb/>
              stone in this by agitating it up and down and turning it over with a small
                <lb/>
              wooden trowel. </s>
              <s>A transverse trough is put under the launder, which is
                <lb/>
              either open on one end and drains off into a tub or settling-pit, or else is
                <lb/>
              closed and perforated through the bottom; in this case, it drains into a
                <lb/>
              ditch beneath, where the water falls when the plug has been partly removed.
                <lb/>
              </s>
              <s>The nature of this ditch I will now describe.</s>
            </p>
            <p type="main">
              <s>If the locality does not supply an abundance of water, the washers dig a
                <lb/>
              ditch thirty or thirty-six feet long, and cover the bottom, the full length, with
                <lb/>
              logs joined together and hewn on the side which lies flat on the ground. </s>
              <s>On
                <lb/>
              each side of the ditch, and at its head also, they place four logs, one above
                <lb/>
              the other, all hewn smooth on the inside. </s>
              <s>But since the logs are laid
                <lb/>
              obliquely along the sides, the upper end of the ditch is made four feet wide
                <lb/>
              and the tail end, two feet. </s>
              <s>The water has a high drop from a launder and
                <lb/>
              first of all it falls into interlaced fir twigs, in order that it shall fall straight
                <lb/>
              down for the most part in an unbroken stream and thus break up the lumps
                <lb/>
              by its weight. </s>
              <s>Some do not place these twigs under the end of the launder,
                <lb/>
              but put a plug in its mouth, which, since it does not entirely close the launder,
                <lb/>
              nor altogether prevent the discharge from it, nor yet allow the water to
                <lb/>
              spout far afield, makes it drop straight down. </s>
              <s>The workman brings in a
                <lb/>
              wheelbarrow the material to be washed, and throws it into the ditch. </s>
              <s>The
                <lb/>
              washer standing in the upper end of the ditch breaks the lumps with a seven­
                <lb/>
              pronged fork, and throws out the roots of trees, shrubs, and grass with the
                <lb/>
              same instrument, and thereby the small black stones settle down. </s>
              <s>When a
                <lb/>
              large quantity of the tin-stone has accumulated, which generally happens
                <lb/>
              when the washer has spent a day at this work, to prevent it from being
                <lb/>
              washed away he places it upon the bank, and other material having been
                <lb/>
              again thrown into the upper end of the ditch, he continues the task of washing.
                <lb/>
              </s>
              <s>A boy stands at the lower end of the ditch, and with a thin pointed hoe
                <lb/>
              stirs up the sediment which has settled at the lower end, to prevent the
                <lb/>
              washed tin-stone from being carried further, which occurs when the sediment
                <lb/>
              has accumulated to such an extent that the fir branches at the outlet of the
                <lb/>
              ditch are covered.</s>
            </p>
          </chap>
        </body>
      </text>
    </archimedes>
Impressum