of iron pyrites. This pyrites is very frequently mixed with beautiful
crystals o f actinolite, o f considerable quantity, which gives it, when
fresh broken, a very splendid appearance. This actinolite is likewise
found in the neighbourhood in chlorite slate, crystallized in very regular
four-sided prisms, about an inch in length, and having a greyish
blue colour.
Whether the original great conical mass o f ore constituted a vein
or not, it is impossible to say; all means of tracing any thing respecting
its situation having been long ago destroyed. But several veins
filled with a similar ore still exist, and have been wrought. This will
be best seen by the two maps of the Fahlun mine which accompany
this chapter. They are copied from a very accurate set of charts of
this mine, constructed by Baron Hermelin. I compared them with
the mine on the spot, and thus was enabled, in some measure, to
judge o f their accuracy. The first of these maps represents the
surface o f the ground over the mine and its environs. I shall give an
explanation of the references in it at the end of this chapter.
The second map, given in plate 10, represents a perpendicular
section o f the mine from east to west, through King Adolphus Frederick's
shaft, and from south-east to north-west by Queen Louisa
Ulrica’s shaft, which shews the union of Prince Gustavus and Lil-
jenberg veins, where the contents of the Stora Grufva terminate.
An explanation of the references contained in this section will also be
found at the end o f the chapter.
The ore is drawn up the perpendicular shafts. The principal one
o f which, King Adolphus Frederick’s shaft, is seen in the perpendicular
section-of the mine, plate 10. All the machinery belonging to this
mine is driven by water; and as far as my observations went, the
whole is constructed according to very scientific and sound principles.
The whole wood-work o f the mine is impregnated with sulphate of
iron. The water that collects in the mine contains likewise a
portion of the same salt in solution. As this water contains likewise
a little sulphate of copper, it is pumped up, and made to run slowly
through a pretty long trough, containing pieces of old iron. By this
contrivance the copper is precipitated. It is collected occasionally,
and smelted. The water, thus freed from copper, though it contains
sulphate of iron, is by much too weak to render it profitable to
crystallize the salt by means of heat. It is concentrated by a very
ingenious method, borrowed from the method used in Germany to
concentrate some o f their weak salt brines. The water is pumped up
to the- top of a pretty high wooden stage, all wrapt round with birch
twigs. It is let fall upon these twigs, and trickles over them to a
trough, at the bottom of the stage, prepared to receive it : by this
contrivance a very great surface o f the liquid is exposed to the air,
which greatly facilitates its evaporation. This process is repeated
seven times, as the liquid moves along from one extremity o f the
stage to the other. By this time it is so much concentrated, as not to
be very far from the point o f crystallization. From this stage it runs
into a large vessel lined with lead, where it is sufficiently concentrated
by boiling. It is then let into a number o f small square wooden
vessels, set beside each other in a large apartment for the purpose.
Into each of thèse vessels a number o f wooden rods, fixed to a frame,
is dipped. Upon these rods the sulphate of iron crystallizes. The
copperas thus manufactured is used in Sweden, and exported to
different ports in the Baltic. The manufacture, unless I misunderstood
the workmen, belongs to Assessor Gahn,
Assessor Gahn has likewise a' very simple apparatus for distilling the
iron pyrites, and obtaining the sulphur. It consists of a long wooden
box, laid along the ground, which serves the purpose of a flue to the
furnace, or still, in which the pyrites is roasted. The sulphur is
deposited in this wooden box, the top o f which may be lifted off
at pleasure, and the sulphur swept out. It is again melted, and
cast into rolls. Sulphur obtained by this means is never quite pure,
usually containing one or more o f the very volatile metals, and sometimes
traces o f copper, and very frequently o f iron. Its colour is
always pale, and not so beautiful as that o f flower o f sulphur.
The whole surface of the plain on which the mine is situated is thick
2 f 2