Agricola, Georgius, De re metallica, 1912/1950

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      <text>
        <body>
          <chap>
            <p type="main">
              <s>
                <pb pagenum="566"/>
              greater part of the water has evaporated. </s>
              <s>The earthy sediment deposited
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              at the bottom of the caldron is composed of fatty and aluminous matter, which
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              usually consists of small incrustations, in which there is not infrequently found
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              a very white and very light powder of asbestos or gypsum. </s>
              <s>The solution now
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              seems to be full of meal. </s>
              <s>Some people instead pour the partly evaporated
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              solution into a vat, so that it may become pure and clear; then pouring it
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              back into the caldron, they boil it again until it becomes mealy. </s>
              <s>By which­
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              ever process it has been condensed, it is then poured into a wooden tub
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              sunk into the earth in order to cool it. </s>
              <s>When it becomes cold it is poured
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              into vats, in which are arranged horizontal and vertical twigs, to which the
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              alum clings when it condenses; and thus are made the small white trans­
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              parent cubes, which are laid to dry in hot rooms.</s>
            </p>
            <p type="main">
              <s>If vitriol forms part of the aluminous ore, the material is dissolved in
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              water without being mixed with urine, but it is necessary to pour that into
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              the clear and pure solution when it is to be re-boiled. </s>
              <s>This separates the
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              vitriol from the alum, for by this method the latter sinks to the bottom of the
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              caldron, while the former floats on the top; both must be poured separately
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              into smaller vessels, and from these into vats to condense. </s>
              <s>If, however, when
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              the solution was re-boiled they did not separate, then they must be poured
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              from the smaller vessels into larger vessels and covered over; then the vitriol
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              separating from the alum, it condenses. </s>
              <s>Both are cut out and put to dry in
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              the hot room, and are ready to be sold; the solution which did not congeal in </s>
            </p>
          </chap>
        </body>
      </text>
    </archimedes>
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