Agricola, Georgius, De re metallica, 1912/1950

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    <archimedes>
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          <chap>
            <p type="caption">
              <s>
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              palm long and a palm wide; small pieces of charcoal, after being laid thereon,
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              can be placed quickly in the furnace through its mouth with a pair of tongs,
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              or again, if necessary, can be taken out of the furnace and laid there.</s>
            </p>
            <p type="main">
              <s>The iron assay furnace is made of four iron bars a foot and a half high,
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              which at the bottom are bent outward and broadened a short distance to enable
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              them to stand more firmly; the front part of the furnace is made from two
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              of these bars, and the back part from two of them; to these bars on both
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              sides are joined and welded three iron cross-bars, the first at a height of a palm
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              from the bottom, the second at a height of a foot, and the third at the top.
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              </s>
              <s>The upright bars are perforated at that point where the side cross-bars are
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              joined to them, in order that three similar iron bars on the remaining sides
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              can be engaged in them; thus there are twelve cross-bars, which make
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              three stages at unequal intervals. </s>
              <s>At the lower stage, the upright bars are
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              distant from each other one foot and five digits; and at the middle stage the
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              front is distant from the back three palms and one digit, and the sides are
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              distant from each other three palms and as many digits; at the highest stage
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              from the front to the back there is a distance of two palms, and between the
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              sides three palms, so that in this way the furnace becomes narrower at the
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              top. </s>
              <s>Furthermore, an iron rod, bent to the shape of the mouth, is set into
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              the lowest bar of the front; this mouth, just like that of the brick furnace,
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              is a palm high and five digits wide. </s>
              <s>Then the front cross-bar of the lower
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              stage is perforated on each side of the mouth, and likewise the back one;
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              through these perforations there pass two iron rods, thus making altogether
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              four bars in the lower stage, and these support an iron plate smeared with
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              lute; part of this plate also projects outside the furnace. </s>
              <s>The outside of
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              the furnace from the lower stage to the upper, is covered with iron plates,
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              which are bound to the bars by iron wires, and smeared with lute to enable
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              them to bear the heat of the fire as long as possible.</s>
            </p>
            <p type="main">
              <s>As for the clay furnace, it must be made of fat, thick clay, medium so
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              far as relates to its softness or hardness. </s>
              <s>This furnace has exactly the same
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              height as the iron one, and its base is made of two earthenware tiles, one
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              foot and three palms long and one foot and one palm wide. </s>
              <s>Each side of the
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              fore part of both tiles is gradually cut away for the length of a palm, so
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              that they are half a foot and a digit wide, which part projects from the
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              furnace; the tiles are about a digit and a half thick. </s>
              <s>The walls are similarly
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              of clay, and are set on the lower tiles at a distance of a digit from the edge,
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              and support the upper tiles; the walls are three digits high and have four
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              openings, each of which is about three digits high; those of the back part and
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              of each side are five digits wide, and of the front, a palm and a half wide, to
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              enable the freshly made cupels to be conveniently placed on the hearth, when
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              it has been thoroughly warmed, that they may be dried there. </s>
              <s>Both tiles
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              are bound on the outer edge with iron wire, pressed into them, so that they
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              will be less easily broken; and the tiles, not unlike the iron bed-plate, have
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              three openings three digits long and a digit wide, in order that when the upper
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              one on account of the heat of the fire or for some other reason has become
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              damaged, the lower one may be exchanged and take its place. </s>
              <s>Through these </s>
            </p>
          </chap>
        </body>
      </text>
    </archimedes>
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