Agricola, Georgius, De re metallica, 1912/1950

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      <text>
        <body>
          <chap>
            <p type="caption">
              <s>
                <pb pagenum="224"/>
              anyone coming at an inopportune moment might disturb his thoughts when
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              they are intent on the work. </s>
              <s>It is also necessary for him to place his balances
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              in a case, so that when he weighs the little buttons of metal the scales may
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              not be agitated by a draught of air, for that is a hindrance to his work.</s>
            </p>
            <p type="main">
              <s>Now I will describe the different things which are necessary in assaying,
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              beginning with the assay furnace, of which one differs from another in
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              shape, material, and the place in which it is set. </s>
              <s>In shape, they may be
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              round or rectangular, the latter shape being more suited to assaying ores.
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              </s>
              <s>The materials of the assay furnaces differ, in that one is made of bricks,
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              another of iron, and certain ones of clay. </s>
              <s>The one of bricks is built on a
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              chimney-hearth which is three and a half feet high; the iron one is placed
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              in the same position, and also the one of clay. </s>
              <s>The brick one is a cubit high,
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              a foot wide on the inside, and one foot two digits long; at a point five digits
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              above the hearth—which is usually the thickness of an unbaked
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              2
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              brick—
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              an iron plate is laid, and smeared over with lute on the upper side to prevent
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              it from being injured by the fire; in front of the furnace above the plate is a
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              mouth a palm high, five digits wide, and rounded at the top. </s>
              <s>The iron plate </s>
            </p>
            <figure number="129"/>
            <p type="caption">
              <s>A—OPENINGS IN THE PLATE. B—PART OF PLATE WHICH PROJECTS BEYOND THE FURNACE.
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              has three openings which are one digit wide and three digits long, one is at
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              each side and the third at the back; through them sometimes the ash falls
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              from the burning charcoal, and sometimes the draught blows through the
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              chamber which is below the iron plate, and stimulates the fire. </s>
              <s>For this
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              reason this furnace when used by metallurgists is named from assaying, but
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              when used by the alchemists it is named from the wind
                <emph type="sup"/>
              3
                <emph.end type="sup"/>
              . </s>
              <s>The part of the
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              iron plate which projects from the furnace is generally three-quarters of a
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              </s>
            </p>
          </chap>
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