Agricola, Georgius, De re metallica, 1912/1950

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    <archimedes>
      <text>
        <body>
          <chap>
            <pb/>
            <p type="head">
              <s>
                <emph type="bold"/>
              BOOK VII.
                <emph.end type="bold"/>
              </s>
            </p>
            <p type="main">
              <s>Since the Sixth Book has described the iron tools,
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              the vessels and the machines used in mines, this
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              Book will describe the methods of assaying
                <emph type="sup"/>
              1
                <emph.end type="sup"/>
              ores;
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              because it is desirable to first test them in order
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              that the material mined may be advantageously
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              smelted, or that the dross may be purged away and
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              the metal made pure. </s>
              <s>Although writers have men­
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              tioned such tests, yet none of them have set down the
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              directions for performing them, wherefore it is no
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              wonder that those who come later have written nothing on the subject.
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              </s>
              <s>By tests of this kind miners can determine with certainty whether
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              ores contain any metal in them or not; or if it has already been
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              indicated that the ore contains one or more metals, the tests show whether
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              it is much or little; the miners also ascertain by such tests the method by
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              which the metal can be separated from that part of the ore devoid of it;
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              and further, by these tests, they determine that part in which there is much
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              metal from that part in which there is little. </s>
              <s>Unless these tests have been
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              carefully applied before the metals are melted out, the ore cannot be smelted
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              without great loss to the owners, for the parts which do not easily melt in the
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              fire carry the metals off with them or consume them. </s>
              <s>In the last case, they pass
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              off with the fumes; in the other case they are mixed with the slag and furnace
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              accretions, and in such event the owners lose the labour which they have spent
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              in preparing the furnaces and the crucibles, and further, it is necessary for them
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              to incur fresh expenditure for fluxes and other things. </s>
              <s>Metals, when they have
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              been melted out, are usually assayed in order that we may ascertain what pro­
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              portion of silver is in a
                <emph type="italics"/>
              centumpondium
                <emph.end type="italics"/>
              of copper or lead, or what quantity of
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              gold is in one
                <emph type="italics"/>
              libra
                <emph.end type="italics"/>
              of silver; and, on the other hand, what proportion of copper
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              or lead is contained in a
                <emph type="italics"/>
              centumpondium
                <emph.end type="italics"/>
              of silver, or what quantity of silver is
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              contained in one
                <emph type="italics"/>
              libra
                <emph.end type="italics"/>
              of gold. </s>
              <s>And from this we can calculate whether it
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              will be worth while to separate the precious metals from the base metals, or
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              not. </s>
              <s>Further, a test of this kind shows whether coins are good or are
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              debased; and readily detects silver, if the coiners have mixed more than is
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              lawful with the gold; or copper, if the coiners have alloyed with the gold or
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              silver more of it than is allowable. </s>
              <s>I will explain all these methods with the
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              utmost care that I can.</s>
            </p>
          </chap>
        </body>
      </text>
    </archimedes>
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