Agricola, Georgius, De re metallica, 1912/1950

List of thumbnails

< >
121
121 		122
122
123
123 		124
124
125
125 		126
126
127
127 		128
128
129
129 		130
130
< >
page |< < of 679 > >|
    <archimedes>
      <text>
        <body>
          <chap>
            <p type="main">
              <s>
                <pb pagenum="117"/>
              which the tin itself is made, and a material they dig up resembling litharge;
                <lb/>
              of iron, iron rust. </s>
              <s>Gold and copper are equally indicated by chrysocolla and
                <lb/>
              azure; silver and lead, by the lead. </s>
              <s>But, though miners rightly
                <lb/>
              call bismuth “the roof of silver,” and though copper pyrites is the common
                <lb/>
              parent of vitriol and
                <emph type="italics"/>
              melantería,
                <emph.end type="italics"/>
              still these sometimes have their own
                <lb/>
              peculiar minerals, just as have orpiment and
                <emph type="italics"/>
              stibium.
                <emph.end type="italics"/>
              </s>
            </p>
            <p type="main">
              <s>Now, just as certain vein materials give miners a favourable indication,
                <lb/>
              so also do the rocks through which the
                <emph type="italics"/>
              canales
                <emph.end type="italics"/>
              of the veins wind their
                <lb/>
              way, for sand discovered in a mine is reckoned among the good indications,
                <lb/>
              especially if it is very fine. </s>
              <s>In the same way schist, when it is of a
                <lb/>
              bluish or blackish colour, and also limestone, of whatever colour it may be, is
                <lb/>
              a good sign for a silver vein. </s>
              <s>There is a rock of another kind that is a good sign;
                <lb/>
              in it are scattered tiny black stones from which tin is smelted; especially when
                <lb/>
              the whole space between the veins is composed of this kind of rock.
                <lb/>
              </s>
              <s>Very often indeed, this good kind of rock in conjunction with valuable
                <lb/>
              stringers contains within its folds the
                <emph type="italics"/>
              canales
                <emph.end type="italics"/>
              of mineral bearing veins: if
                <lb/>
              it descends vertically into the earth, the benefit belongs to that mine in
                <lb/>
              which it is seen first of all; if inclined, it benefits the other neighbouring
                <lb/>
              mines
                <emph type="sup"/>
              12
                <emph.end type="sup"/>
              . </s>
              <s>As a result the miner who is not ignorant of geometry can calculate
                <lb/>
              from the other mines the depth at which the
                <emph type="italics"/>
              canales
                <emph.end type="italics"/>
              of a vein bearing rich
                <lb/>
              metal will wind its way through the rock into his mine. </s>
              <s>So much for these
                <lb/>
              matters.</s>
            </p>
            <p type="main">
              <s>I now come to the mode of working, which is varied and complex, for in
                <lb/>
              some places they dig crumbling ore, in others hard ore, in others a harder
                <lb/>
              ore, and in others the hardest kind of ore. </s>
              <s>In the same way, in some places
                <lb/>
              the hangingwall rock is soft and fragile, in others hard, in others harder, and
                <lb/>
              in still others of the hardest sort. </s>
              <s>I call that ore “crumbling” which is com­
                <lb/>
              posed of earth, and of soft solidified juices; that ore “hard” which is composed
                <lb/>
              of metallic minerals and moderately hard stones, such as for the most part
                <lb/>
              are those which easily melt in a fire of the first and second orders, like lead
                <lb/>
              and similar materials. </s>
              <s>I call that ore “harder” when with those I have already
                <lb/>
              mentioned are combined various sorts of quartz, or stones which easily melt
                <lb/>
              in fire of the third degree, or pyrites, or
                <emph type="italics"/>
              cadmia,
                <emph.end type="italics"/>
              or very hard marble. </s>
              <s>I call
                <lb/>
              that ore hardest, which is composed throughout the whole vein of these hard
                <lb/>
              stones and compounds. </s>
              <s>The hanging or footwalls of a vein are hard, when
                <lb/>
              composed of rock in which there are few stringers or seams; harder, in
                <lb/>
              which they are fewer; hardest, in which they are fewest or none at all.
                <lb/>
              </s>
              <s>When these are absent, the rock is quite devoid of water which softens
                <lb/>
              it. </s>
              <s>But the hardest rock of the hanging or footwall, however, is seldom as
                <lb/>
              hard as the harder class of ore.</s>
            </p>
            <p type="main">
              <s>Miners dig out crumbling ore with the pick alone. </s>
              <s>When the metal
                <lb/>
              has not yet shown itself, they do not discriminate between the hangingwall
                <lb/>
              and the veins; when it has once been found, they work with the utmost care.
                <lb/>
              </s>
              <s>For first of all they tear away the hangingwall rock separately from the vein,
                <lb/>
              afterward with a pick they dislodge the crumbling vein from the footwall </s>
            </p>
          </chap>
        </body>
      </text>
    </archimedes>
Impressum