Agricola, Georgius, De re metallica, 1912/1950

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    <archimedes>
      <text>
        <body>
          <chap>
            <p type="main">
              <s>
                <pb pagenum="516"/>
              are so placed on the sole-stones that they project a palm at the sides, and at the
                <lb/>
              front the sole-stones project to the same extent; if rectangular stones are
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              not available, bricks are laid in their place. </s>
              <s>The copper plates are four feet
                <lb/>
              two palms and as many digits long, a cubit wide, and a palm thick; each
                <lb/>
              edge has a protuberance, one at the front end, the other at the back; these
                <lb/>
              are a palm and three digits long, and a palm wide and thick. </s>
              <s>The plates are
                <lb/>
              so laid upon the rectangular stones that their rear ends are three digits from
                <lb/>
              the third long wall; the stones project beyond the plate the same number
                <lb/>
              of digits in front, and a palm and three digits at the sides. </s>
              <s>When the plates
                <lb/>
              have been joined, the groove which is between the protuberances is a palm
                <lb/>
              and three digits wide, and four feet long, and through it flows the silver-lead
                <lb/>
              which liquates from the cakes. </s>
              <s>When the plates are corroded either by the
                <lb/>
              fire or by the silver-lead, which often adheres to them in the form of stalac­
                <lb/>
              tites, and is chipped off, they are exchanged, the right one being placed to the
                <lb/>
              left, and the left one, on the contrary, to the right; but the left side of the
                <lb/>
              plates, which, when the fusion of the copper took place, came into contact
                <lb/>
              with the copper, must lie flat; so that when the exchange of the plates has
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              been carried out, the protuberances, which are thus on the underside, raise
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              the plate from the stones, and they have to be partially chipped off, lest they
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              should prove an impediment to the work; and in each of their places is
                <lb/>
              laid a piece of iron, three palms long, a digit thick at both ends, and a palm
                <lb/>
              thick in the centre for the length of a palm and three digits.</s>
            </p>
            <p type="main">
              <s>The passage under the plates between the rectangular stones is a foot
                <lb/>
              wide at the back, and a foot and a palm wide at the front, for it gradually
                <lb/>
              widens out. </s>
              <s>The hearth, which is between the sole-stones, is covered with a
                <lb/>
              bed of hearth-lead, taken from the crucible in which lead is separated from
                <lb/>
              silver. </s>
              <s>The rear end is the highest, and should be so high that it reaches to
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              within six digits of the plates, from which point it slopes down evenly to the
                <lb/>
              front end, so that the argentiferous lead alloy which liquates from the cakes
                <lb/>
              can flow into the receiving-pit. </s>
              <s>The wall built against the third long wall
                <lb/>
              in order to protect it from injury by fire, is constructed of bricks joined
                <lb/>
              together with lute, and stands on the copper plates; this wall is two feet, a
                <lb/>
              palm and two digits high, two palms thick, and three feet, a palm and three
                <lb/>
              digits wide at the bottom, for it reaches across both of them; at the top it is
                <lb/>
              three feet wide, for it rises up obliquely on each side. </s>
              <s>At each side of this wall,
                <lb/>
              at a height of a palm and two digits above the top of it, there is inserted in a
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              hole in the third long wall a hooked iron rod, fastened in with molten lead;
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              the rod projects two palms from the wall, and is two digits wide and one
                <lb/>
              digit thick; it has two hooks, the one at the side, the other at the end.
                <lb/>
              </s>
              <s>Both of these hooks open toward the wall, and both are a digit thick, and
                <lb/>
              both are inserted in the last, or the adjacent, links of a short iron chain. </s>
              <s>This
                <lb/>
              chain consists of four links, each of which is a palm and a digit long and half
                <lb/>
              a digit thick; the first link is engaged in the first hole in a long iron rod, and
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              one or other of the remaining three links engages the hook of the hooked rod.
                <lb/>
              </s>
              <s>The two long rods are three feet and as many palms and digits long, two
                <lb/>
              digits wide, and one digit thick; both ends of both of these rods have holes, </s>
            </p>
          </chap>
        </body>
      </text>
    </archimedes>
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