Agricola, Georgius, De re metallica, 1912/1950

Table of figures

< >
[Figure 131]
Page: 266
[Figure 132]
Page: 267
[Figure 133]
Page: 269
[Figure 134]
Page: 278
[Figure 135]
Page: 278
[Figure 136]
Page: 279
[Figure 137]
Page: 288
[Figure 138]
Page: 293
[Figure 139]
Page: 300
[Figure 140]
Page: 303
[Figure 141]
Page: 304
[Figure 142]
Page: 306
[Figure 143]
Page: 307
[Figure 144]
Page: 308
[Figure 145]
Page: 309
[Figure 146]
Page: 310
[Figure 147]
Page: 312
[Figure 148]
Page: 313
[Figure 149]
Page: 314
[Figure 150]
Page: 315
[Figure 151]
Page: 316
[Figure 152]
Page: 322
[Figure 153]
Page: 323
[Figure 154]
Page: 324
[Figure 155]
Page: 325
[Figure 156]
Page: 326
[Figure 157]
Page: 327
[Figure 158]
Page: 329
[Figure 159]
Page: 330
[Figure 160]
Page: 331
< >
page |< < of 679 > >|
    <archimedes>
      <text>
        <body>
          <chap>
            <pb pagenum="240"/>
            <p type="main">
              <s>If the whole space of the furnace covered by the muffle is not filled with
                <lb/>
              scorifiers, cupels are put in the empty space, in order that they may become
                <lb/>
              warmed in the meantime. </s>
              <s>Sometimes, however, it is filled with scorifiers,
                <lb/>
              when we are assaying many different ores, or many portions of one ore at the
                <lb/>
              same time. </s>
              <s>Although the cupels are usually dried in one hour, yet smaller
                <lb/>
              ones are done more quickly, and the larger ones more slowly. </s>
              <s>Unless the
                <lb/>
              cupels are heated before the metal mixed with lead is placed in them, they </s>
            </p>
            <figure number="134"/>
            <p type="caption">
              <s>A—CLAWS OF THE TONGS. B—IRON, GIVING FORM OF AN EGG. C—OPENING.
                <lb/>
              frequently break, and the lead always sputters and sometimes leaps out of them;
                <lb/>
              if the cupel is broken or the lead leaps out of it, it is necessary to assay
                <lb/>
              another portion of ore; but if the lead only sputters, then the cupels should
                <lb/>
              be covered with broad thin pieces of glowing charcoal, and when the lead
                <lb/>
              strikes these, it falls back again, and thus the mixture is slowly exhaled.
                <lb/>
              </s>
              <s>Further, if in the cupellation the lead which is in the mixture is not con­
                <lb/>
              sumed, but remains fixed and set, and is covered by a kind of skin, this is a
                <lb/>
              sign that it has not been heated by a sufficiently hot fire; put into the
                <lb/>
              mixture, therefore, a dry pine stick, or a twig of a similar tree, and hold it
                <lb/>
              in the hand in order that it can be drawn away when it has been heated.
                <lb/>
              </s>
              <s>Then take care that the heat is sufficient and equal; if the heat has not
                <lb/>
              passed all round the charge, as it should when everything is done rightly,
                <lb/>
              but causes it to have a lengthened shape, so that it appears to have a tail,
                <lb/>
              this is a sign that the heat is deficient where the tail lies. </s>
              <s>Then in order
                <lb/>
              that the cupel may be equally heated by the fire, turn it around with a small
                <lb/>
              iron hook, whose handle is likewise made of iron and is a foot and a half long.</s>
            </p>
            <figure number="135"/>
            <p type="caption">
              <s>SMALL IRON HOOK.</s>
            </p>
            <p type="main">
              <s>Next, if the mixture has not enough lead, add as much of it as is required
                <lb/>
              with the iron tongs, or with the brass ladle to which is fastened a very long
                <lb/>
              handle. </s>
              <s>In order that the charge may not be cooled, warm the lead beforehand. </s>
            </p>
          </chap>
        </body>
      </text>
    </archimedes>
Impressum