Agricola, Georgius, De re metallica, 1912/1950

Table of figures

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    <archimedes>
      <text>
        <body>
          <chap>
            <p type="main">
              <s>
                <pb pagenum="364"/>
              piece keeps the ends of the bow distended, and is placed a cubit distant from
                <lb/>
              the head of the bellows; the ends of this piece are mortised into the ends
                <lb/>
              of the bow and are joined and glued to them; its length without the tenons
                <lb/>
              is a foot, and its width a palm and two digits. </s>
              <s>There are, besides, two other
                <lb/>
              very small pieces glued to the head of the bellows and to the lower board,
                <lb/>
              and fastened to them by wooden pegs covered with glue, and they are three
                <lb/>
              palms and two digits long, one palm high, and a digit thick, one half being
                <lb/>
              slightly cut away. </s>
              <s>These pieces keep the ends of the bow away from the
                <lb/>
              hole in the bellows-head, for if they were not there, the ends, forced inward
                <lb/>
              by the great and frequent movement, would be broken.</s>
            </p>
            <p type="main">
              <s>The leather is of ox-hide or horse-hide, but that of the ox is far preferable
                <lb/>
              to that of the horse. </s>
              <s>Each of these hides, for there are two, is three and a
                <lb/>
              half feet wide where they are joined at the back part of the bellows. </s>
              <s>A
                <lb/>
              long leathern thong is laid along each of the bellows-boards and each of the
                <lb/>
              bows, and fastened by T-shaped iron nails five digits long; each of the
                <lb/>
              horns of the nails is two and a half digits long and half a digit wide. </s>
              <s>The
                <lb/>
              hide is attached to the bellows-boards by means of these nails, so that a horn
                <lb/>
              of one nail almost touches the horn of the next; but it is different with the
                <lb/>
              bows, for the hide is fastened to the back piece of the bow by only two nails,
                <lb/>
              and to the two long pieces by four nails. </s>
              <s>In this practical manner they put
                <lb/>
              ten nails in one bow and the same number in the other. </s>
              <s>Sometimes when the
                <lb/>
              smelter is afraid that the vigorous motion of the bellows may pull or tear
                <lb/>
              the hide from the bows, he also fastens it with little strips of pine by means of
                <lb/>
              another kind of nail, but these strips cannot be fastened to the back pieces of
                <lb/>
              the bow, because these are somewhat bent. </s>
              <s>Some people do not fix the
                <lb/>
              hide to the bellows-boards and bows by iron nails, but by iron screws,
                <lb/>
              screwed at the same time through strips laid over the hide. </s>
              <s>This method
                <lb/>
              of fastening the hide is less used than the other, although there is no doubt
                <lb/>
              that it surpasses it in excellence.</s>
            </p>
            <p type="main">
              <s>Lastly, the head of the bellows, like the rest of the body, consists of two
                <lb/>
              boards, and of a nozzle besides. </s>
              <s>The upper board is one cubit long, one and a
                <lb/>
              half palms thick. </s>
              <s>The lower board is part of the whole of the lower bellows­
                <lb/>
              board; it is of the same length as the upper piece, but a palm and a digit
                <lb/>
              thick. </s>
              <s>From these two glued together is made the head, into which, when it
                <lb/>
              has been perforated, the nozzle is fixed. </s>
              <s>The back part of the head, where
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              it is attached to the rest of the bellows-body, is a cubit wide, but three palms
                <lb/>
              forward it becomes two digits narrower. </s>
              <s>Afterward it is somewhat cut
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              away so that the front end may be rounded, until it is two palms and as
                <lb/>
              many digits in diameter, at which point it is bound with an iron ring three
                <lb/>
              digits wide.</s>
            </p>
            <p type="main">
              <s>The nozzle is a pipe made of a thin plate of iron; the diameter in front is
                <lb/>
              three digits, while at the back, where it is encased in the head of the bellows,
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              it is a palm high and two palms wide. </s>
              <s>It thus gradually widens out, especially
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              at the back, in order that a copious wind can penetrate into it; the whole
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              nozzle is three feet long.</s>
            </p>
          </chap>
        </body>
      </text>
    </archimedes>
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