Agricola, Georgius
,
De re metallica
,
1912/1950
Text
Text Image
Image
XML
Thumbnail overview
Document information
None
Concordance
Figures
Thumbnails
Page concordance
<
1 - 30
31 - 60
61 - 90
91 - 120
121 - 150
151 - 180
181 - 210
211 - 240
241 - 270
271 - 300
301 - 330
331 - 360
361 - 390
391 - 420
421 - 450
451 - 480
481 - 510
511 - 540
541 - 570
571 - 600
601 - 630
631 - 660
661 - 679
>
Scan
Original
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
<
1 - 30
31 - 60
61 - 90
91 - 120
121 - 150
151 - 180
181 - 210
211 - 240
241 - 270
271 - 300
301 - 330
331 - 360
361 - 390
391 - 420
421 - 450
451 - 480
481 - 510
511 - 540
541 - 570
571 - 600
601 - 630
631 - 660
661 - 679
>
page
|<
<
of 679
>
>|
<
archimedes
>
<
text
>
<
body
>
<
chap
>
<
p
type
="
main
">
<
s
>
<
pb
pagenum
="
249
"/>
with the mouth and then a blue flame will be emitted. </
s
>
<
s
>In the end the tubes
<
lb
/>
are weighed, and if their weights prove equal, he who has undertaken this work
<
lb
/>
has not laboured in vain. </
s
>
<
s
>Lastly, both are placed in another balance-pan and
<
lb
/>
weighed; of each tube four grains must not be counted, on account of the
<
lb
/>
silver which remains in the gold and cannot be separated from it. </
s
>
<
s
>From the
<
lb
/>
weight of the tubes we learn the weight both of the gold and of the silver
<
lb
/>
which is in the button. </
s
>
<
s
>If some assayer has omitted to add so much silver to
<
lb
/>
the gold as to make it three times the quantity, but only double, or two and a
<
lb
/>
half times as much, he will require the stronger quality of
<
emph
type
="
italics
"/>
aqua
<
emph.end
type
="
italics
"/>
which
<
lb
/>
separates gold from silver, such as the fourth quality. </
s
>
<
s
>Whether the
<
emph
type
="
italics
"/>
aqua
<
emph.end
type
="
italics
"/>
<
lb
/>
which he employs for gold and silver is suitable for the purpose, or whether
<
lb
/>
it is more or less strong than is right, is recognised by its effect. </
s
>
<
s
>That of
<
lb
/>
medium strength raises the little bubbles on the tubes and is found to colour
<
lb
/>
the ampulla and the operculum a strong red; the weaker one is found to
<
lb
/>
colour them a light red, and the stronger one to break the tubes. </
s
>
<
s
>To pure
<
lb
/>
silver in which there is some portion of gold, nothing should be added when
<
lb
/>
they are being heated in the cupel prior to their being parted, except a
<
emph
type
="
italics
"/>
bes
<
emph.end
type
="
italics
"/>
<
lb
/>
of lead and one-fourth or one-third its amount of copper of the lesser weights.
<
lb
/>
</
s
>
<
s
>If the silver contains in itself a certain amount of copper, let it be weighed,
<
lb
/>
both after it has been melted with the lead, and after the gold has been parted
<
lb
/>
from it; by the former we learn how much copper is in it, by the latter how
<
lb
/>
much gold. </
s
>
<
s
>Base metals are burnt up even to-day for the purpose of assay,
<
lb
/>
because to lose so little of the metal is small loss, but from a large mass of
<
lb
/>
base metal, the precious metal is always extracted, as I will explain in
<
lb
/>
Books X. and XI.</
s
>
</
p
>
<
p
type
="
main
">
<
s
>We assay an alloy of copper and silver in the following way. </
s
>
<
s
>From a
<
lb
/>
few cakes of copper the assayer cuts out portions, small samples from small
<
lb
/>
cakes, medium samples from medium cakes, and large samples from large
<
lb
/>
cakes; the small ones are equal in size to half a hazel nut, the large
<
lb
/>
ones do not exceed the size of half a chestnut, and those of medium size come
<
lb
/>
between the two. </
s
>
<
s
>He cuts out the samples from the middle of the
<
lb
/>
bottom of each cake. </
s
>
<
s
>He places the samples in a new, clean, triangular
<
lb
/>
crucible and fixes to them pieces of paper upon which are written the weight
<
lb
/>
of the cakes of copper, of whatever size they may be; for example, he writes,
<
lb
/>
“These samples have been cut from copper which weighs twenty
<
emph
type
="
italics
"/>
centum
<
lb
/>
pondía.”
<
emph.end
type
="
italics
"/>
When he wishes to know how much silver one
<
emph
type
="
italics
"/>
centumpondíum
<
emph.end
type
="
italics
"/>
of
<
lb
/>
copper of this kind has in it, first of all he throws glowing coals into the
<
lb
/>
iron hoop, then adds charcoal to it. </
s
>
<
s
>When the fire has become hot, the paper
<
lb
/>
is taken out of the crucible and put aside, he then sets that crucible on the
<
lb
/>
fire and gradually heats it for a quarter of an hour until it becomes red hot.
<
lb
/>
</
s
>
<
s
>Then he stimulates the fire by blowing with a blast from the double bellows
<
lb
/>
for half an hour, because copper which is devoid of lead requires this time to
<
lb
/>
become hot and to melt; copper not devoid of lead melts quicker. </
s
>
<
s
>When
<
lb
/>
he has blown the bellows for about the space of time stated, he removes the
<
lb
/>
glowing charcoal with the tongs, and stirs the copper with a splinter of wood,
<
lb
/>
which he grasps with the tongs. </
s
>
<
s
>If it does not stir easily, it is a sign that the </
s
>
</
p
>
</
chap
>
</
body
>
</
text
>
</
archimedes
>