Agricola, Georgius, De re metallica, 1912/1950

Page concordance

< >
Scan Original
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
< >
page |< < of 679 > >|
    <archimedes>
      <text>
        <body>
          <chap>
            <p type="caption">
              <s>
                <pb pagenum="475"/>
              the channel, mixed with charcoal, the scum, as one might say, of the lead;
                <lb/>
              the lead makes this scum when it becomes hot, but that less of it may be
                <lb/>
              made it must be stirred frequently with the bar.</s>
            </p>
            <p type="main">
              <s>Within the space of a quarter of an hour the crucible absorbs the lead;
                <lb/>
              at the time when it penetrates into the crucible it leaps and bubbles. </s>
              <s>Then
                <lb/>
              the master takes out a little lead with an iron ladle, which he assays, in order
                <lb/>
              to find what proportion of silver there is in the whole of the alloy; the
                <lb/>
              ladle is five digits wide, the iron part of its handle is three feet long and the
                <lb/>
              wooden part the same. </s>
              <s>Afterward, when they are heated, he extracts with
                <lb/>
              a bar the litharge which comes from the lead and the copper, if there be any
                <lb/>
              of it in the alloy. </s>
              <s>Wherefore, it might more rightly be called
                <emph type="italics"/>
              spuma
                <emph.end type="italics"/>
              of lead
                <lb/>
              than of silver
                <emph type="sup"/>
              34
                <emph.end type="sup"/>
              . </s>
              <s>There is no injury to the silver, when the lead and copper
                <lb/>
              are separated from it. </s>
              <s>In truth the lead becomes much purer in the crucible
                <lb/>
              of the other furnace, in which silver is refined. </s>
              <s>In ancient times, as the
                <lb/>
              author Pliny
                <emph type="sup"/>
              35
                <emph.end type="sup"/>
              relates, there was under the channel of the crucible another
                <lb/>
              crucible, and the litharge flowed down from the upper one into the lower
                <lb/>
              one, out of which it was lifted up and rolled round with a stick in order that
                <lb/>
              it might be of moderate weight. </s>
              <s>For which reason, they formerly made it
                <lb/>
              into small tubes or pipes, but now, since it is not rolled round a stick, they
                <lb/>
              make it into bars.</s>
            </p>
            <p type="main">
              <s>If there be any danger that the alloy might flow out with the litharge, the
                <lb/>
              foreman keeps on hand a piece of lute, shaped like a cylinder and pointed at
                <lb/>
              both ends; fastening this to a hooked bar he opposes it to the alloy so that
                <lb/>
              it will not flow out.</s>
            </p>
            <p type="main">
              <s>Now when the colour begins to show in the silver, bright spots appear,
                <lb/>
              some of them being almost white, and a moment afterward it becomes
                <lb/>
              absolutely white. </s>
              <s>Then the assistant lets down the water-gates, so that, the
                <lb/>
              race being closed, the water-wheel ceases to turn and the bellows are still.
                <lb/>
              </s>
              <s>Then the master pours several buckets of water on to the silver to cool it;
                <lb/>
              others pour beer over it to make it whiter, but this is of no importance since
                <lb/>
              the silver has yet to be refined. </s>
              <s>Afterward, the cake of silver is raised with
                <lb/>
              the pointed iron bar, which is three feet long and two digits wide, and has a
                <lb/>
              wooden handle four feet long fixed in its socket. </s>
              <s>When the cake of silver has
                <lb/>
              been taken from the crucible, it is laid upon a stone, and from part of it the
                <lb/>
              hearth-lead, and from the other part the litharge, is chipped away with a
                <lb/>
              hammer; then it is cleansed with a bundle of brass wire dipped in water.
                <lb/>
              </s>
              <s>When the lead is separated from the silver, more silver is frequently found
                <lb/>
              than when it was assayed; for instance, if before there were three
                <emph type="italics"/>
              uncíae
                <emph.end type="italics"/>
              and
                <lb/>
              as many
                <emph type="italics"/>
              drachmae
                <emph.end type="italics"/>
              in a
                <emph type="italics"/>
              centumpondíum,
                <emph.end type="italics"/>
              they now sometimes find three
                <emph type="italics"/>
              uncíae
                <emph.end type="italics"/>
                <lb/>
              and a half
                <emph type="sup"/>
              36
                <emph.end type="sup"/>
              . </s>
              <s>Often the hearth-lead remaining in the crucible is a palm
                <lb/>
              deep; it is taken out with the rest of the ashes and is sifted, and that which
                <lb/>
              remains in the sieve, since it is hearth-lead, is added to the hearth-lead
                <emph type="sup"/>
              37
                <emph.end type="sup"/>
              .
                <lb/>
                <lb/>
                <lb/>
              </s>
            </p>
          </chap>
        </body>
      </text>
    </archimedes>
Impressum