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52 SWEDENBORG’S TRAVELS AND DIARIES. [ Doc. 205.
or retort is of considerable size, and well enclosed in clay and
powdered coal. The smelted ore is let off in front towards
the side, and is collected first in a smaller and afterwards in
a larger well. The furnace is in the interior two and a half
feet long, a foot and a half wide, and from the bottom four
feet high. On the top it is vaulted and of brick, and the
smoke is carried off from the furnace, and thus outside the
building, through a capacious chimney. 5. Into this furnace
the 250 hundred-weight of the above ore are transferred, and
yield thirty hundred-weight of copper stone within twenty-four
hours ; the smelted ore is drawn off at the sides into two
wells ; this operation takes place three times, or once every
eighth hour. 6. The copper stone which is thus obtained, is
calcined afterwards five or six times ; at first for eight days,
and subsequently for a shorter period, so that this second
operation of calcining is finished within three weeks. Each
calcining hearth is three and a half ells long, an ell and a
half broad, and an ell and a half high. 7. The calcined stone
is now introduced into the Stichofen, which is of the same
dimensions as the former furnace in height, breadth, and length,
except that the well or receptacle is within the furnace itself,
and the liquefied ore is thus kept within the walls ; it is after
wards drawn off in front, and there are thus obtained thirteen
hundred-weight . of Spurstein, but rarely any copper. 8. This
stone is now again calcined on the same calcining hearths,
and afterwards put back into the furnace, when there are ob
tained about five hundred-weight of copper; some small portions
of the stone float on the top, yet altogether not more than a
few pounds. 9. The scoriæ are first introduced in a crude
state, but afterwards such are used as have recently passed
through the furnace, and so on. 10. At last this black copper,
as it is called, is purified. It must be observed that when
the stone is smelted a second time, this work lasts from
thirteen to fourteen hours ; the molten mass is drawn off six
or seven times. Likewise, when the stone is put in a third
time, and the copper is obtained from it, it is kept in the
furnace and in the well or receptacle for thirteen hours, and
is drawn off only once, or all the metal at the same time.
There is also another kind of furnace, which may either be
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