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Doc. 205.] 45
SWEDENBORG’S TRAVELS IN 1733.
burn longer in the heap. These heaps are of various sizes,
but usually they contain sixty fuder of ore ; one fuder amount
ing to sixty buckets (vasa). After the fire is lighted, and the
opening in front, which leads to the interior structure of wood, has
been opened and afterwards shut, it lasts generally three weeks.
2. After this ore has thus, for the first time, been calcined
in the open air, it is taken into the crushing mill and bruised
into powder. In one building there are several crushing
hammers ; each crushing box has usually three ; in each mill
there are four or five such boxes. The hammers are very
heavy, each being weighted by a large piece of iron beneath,
and they do their work in the usual fashion. 3. The powder
which is obtained by the crushing of the ore is first washed
in the Schlammbank, which is a kind of short trough formed
of two walls, and consisting of two steps, a partition or a dam
being across its foot. By passing it up and down (reactiones)
the thicker and heavier powder is separated from that which
is lighter. Afterwards the powder is transferred to the
washing grounds, which are furnished with cloths or sods,
where it is washed in the usual way ; the operation of washing
being continued until nothing of the stony part remains, and
only the pure ore can be seen ; this ore also is tried and ex
perimented upon by the assayers in their assaying vessels.
4. After the ore has been reduced to powder, and the metallic
portion separated from the stony, it is put into an oven, which
is not unlike a baker’s oven, or those used in Saxony for
calcining their silver ores. This oven is bound (
laqueatus) ; it
is about six ells long, four broad, and an ell and a half high;
the opening is semicircular. Into this oven a large quantity
of the pulverized ore is introduced, and pieces of wood are
thrust in everywhere, in front as well as behind. By this fire
the pulverized ore becomes more and more glowing, and by
constantly putting in fresh wood it is ignited. This powdered
ore burning at white heat is continually stirred, and that which
is near the opening of the oven is pushed into the interior,
and vice versa; care being taken that it does not lie too thick,
not thicker than one inch; by stirring the mass continually
time is not given to it to lump. This calcining usually lasts
from fourteen to eighteen hours, and the better the calcining
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