Agricola, Georgius, De re metallica, 1912/1950

Table of figures

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    <archimedes>
      <text>
        <body>
          <chap>
            <p type="main">
              <s>
                <pb pagenum="244"/>
              leather, which sags about one hand's breadth; next, the leather is folded
                <lb/>
              over and tied with a waxed string, and the dish catches the quicksilver
                <lb/>
              which is squeezed through it. </s>
              <s>As for the gold which remains in the leather,
                <lb/>
              it is placed in a scorifier and purified by being placed near glowing coals. </s>
              <s>Others
                <lb/>
              do not wash away the dirt with warm water, but with strong lye and vinegar,
                <lb/>
              for they pour these liquids into the pot, and also throw into it the quicksilver
                <lb/>
              mixed with the concentrates made by washing. </s>
              <s>Then they set the pot in a
                <lb/>
              warm place, and after twenty-four hours pour out the liquids with the dirt, and
                <lb/>
              separate the quicksilver from the gold in the manner which I have described.
                <lb/>
              </s>
              <s>Then they pour urine into a jar set in the ground, and in the jar place a
                <lb/>
              pot with holes in the bottom, and in the pot they place the gold; then the
                <lb/>
              lid is put on and cemented, and it is joined with the jar; they afterward heat
                <lb/>
              it till the pot glows red. </s>
              <s>After it has cooled, if there is copper in the gold
                <lb/>
              they melt it with lead in a cupel, that the copper may be separated from it;
                <lb/>
              but if there is silver in the gold they separate them by means of the
                <emph type="italics"/>
              aqua
                <emph.end type="italics"/>
                <lb/>
              which has the power of parting these two metals. </s>
              <s>There are some who,
                <lb/>
              when they separate gold from quicksilver, do not pour the amalgam into
                <lb/>
              a leather, but put it into a gourd-shaped earthen vessel, which they place
                <lb/>
              in the furnace and heat gradually over burning charcoal; next, with an iron
                <lb/>
              plate, they cover the opening of the operculum, which exudes vapour, and as
                <lb/>
              soon as it has ceased to exude, they smear it with lute and heat it for a short
                <lb/>
              time; then they remove the operculum from the pot, and wipe off the
                <lb/>
              quicksilver which adheres to it with a hare's foot, and preserve it for future
                <lb/>
              use. </s>
              <s>By the latter method, a greater quantity of quicksilver is lost, and by
                <lb/>
              the former method, a smaller quantity.</s>
            </p>
            <p type="main">
              <s>If an ore is rich in silver, as is
                <emph type="italics"/>
              rudis
                <emph.end type="italics"/>
              silver
                <emph type="sup"/>
              29
                <emph.end type="sup"/>
              , frequently silver glance,
                <lb/>
              or rarely ruby silver, gray silver, black silver, brown silver, or yellow silver,
                <lb/>
              as soon as it is cleansed and heated, a
                <emph type="italics"/>
              centumpondíum
                <emph.end type="italics"/>
              (of the lesser weights) of
                <lb/>
              it is placed in an
                <emph type="italics"/>
              uncia
                <emph.end type="italics"/>
              of molten lead in a cupel, and is heated until the lead
                <lb/>
              exhales. </s>
              <s>But if the ore is of poor or moderate quality, it must first be dried,
                <lb/>
              then crushed, and then to a
                <emph type="italics"/>
              centumpondium
                <emph.end type="italics"/>
              (of the lesser weights) an
                <emph type="italics"/>
              uncia
                <emph.end type="italics"/>
                <lb/>
              of lead is added, and it is heated in the scorifier until it melts. </s>
              <s>If it is not
                <lb/>
              soon melted by the fire, it should be sprinkled with a little powder of the
                <lb/>
              first order of fluxes, and if then it does not melt, more is added little by little
                <lb/>
              until it melts and exudes its slag; that this result may be reached sooner,
                <lb/>
              the powder which has been sprinkled over it should be stirred in with an iron
                <lb/>
              rod. </s>
              <s>When the scorifier has been taken out of the assay furnace, the alloy
                <lb/>
              should be poured into a hole in a baked brick; and when it has cooled and been
                <lb/>
              cleansed of the slag, it should be placed in a cupel and heated until it exhales
                <lb/>
              all its lead; the weight of silver which remains in the cupel indicates what
                <lb/>
              proportion of silver is contained in the ore.</s>
            </p>
            <p type="main">
              <s>We assay copper ore without lead, for if it is melted with it, the copper
                <lb/>
              usually exhales and is lost. </s>
              <s>Therefore, a certain weight of such an ore </s>
            </p>
          </chap>
        </body>
      </text>
    </archimedes>
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