stone, only that the disappearing is much more rapid. This curious
property was pointed out to me hy Assessor Gahn, at Fahlun.
The mine o f Sala lies about an English mile west from the town.
Just upon the south side of it, at a distance not greater than one
hundred yards, there is a small hill o f granite, quite round, and about
forty feet in height; the workings have been driven to within a few
yards of this hill, but not quite up to it. 1 This hill may be considered
as the boundary of the granite on the south side. The limestone
comes to its bottom, and the two rocks may be traced in contact,
running in a westerly direction, for some miles. I do not mean that
the junction is visible all the way. It is often covered over with soil
and grass, but every now and then you meet with spots where it is
visible, and which enable you to trace the direction in which it runs.'
The same thing may be said of the junction of the bed of limestone
and the gneiss rocks on the north side of the mine and at a distance,
which, by estimation, I reckon not quite so great as half an English
mile.
In the limestone bed there occur various veins which traverse it
from north-west to south-east. The most important of these is a
vein o f galena, usually mixed with limestone, and occasionally with
blende and pyrites. It is this vein which constitutes what is called
the silver mine of Sala. There is another vein running parallel to
the former, consisting of a mixture of copper pyrites and grey copper
ore; but containing by far the greatest quantity of the former. This
vein is poor, and of little importance. A third vein, apparently
parallel to the two last, is filled with iron, seemingly magnetic ironstone,
mixed with earthy matter, and not very rich in iron. This
ore is not wrought. These three veins, which are of most importance
in consequence o f their metallic nature, are cut by some small
veins, which are filled by quartz and by a kind of hornstone, called
flinta by the Swedes. These cross veins, to which the Swedish
miners give the name of skolen, are always very much inclined.
Besides these two kinds of veins in the limestone, there is still a
third vein, which runs nearly from north to south, and cuts through all
the other veins in its way. It is Consequently the newest of all the
veins in the limestone o f Sala. This vein is filled with basalt ; it
is nearly perpendicular to the horizon, and has a considerable thickness.
I was much struck with this vein, as it contained the only
specimen of basalt which I had met with in Sweden. I f it were
elevated above the surface, it would resemble the whyndykes, so
common on the west coast of Scotland. They usually consist of
greenstone, which is a kindred rock to basalt. A vein of basalt in
a primitive country, quite fiat, and containing no remains of floetz
trap in the neighbourhood, will be admitted, I presume, to be an
interesting, and rather uncommon object. ^
What is called the silver mine of Sala is merely the galena contained
in the vein first mentioned. It has been wrought above 300 years,
and formerly yielded a very considerable quantity o f silver. In the
year 15 o6 the annual produce was 32,266 marks, at present I am told
the quantity extracted does not exceed 2ooo. Formerly this mine had
been wrought in such an unskilful manner that the whole tumbled
down, and a considerable open cavity may be now seen as at Fahlun;
not indeed nearly of so large a size, because the scale o f the Sala mine
is in every respect less. The rock below these debris has been lately
examined, but it was: not found to contain any ore. After the tumbling
in o f the mine, that part of it was abandoned altogether, and anew
excavation made, a little to the north o f the old one. The mine has
been sunk to a depth of 150 fathoms, without any appearance of the
termination of the vein, and it would be worth while to go still deeper.
In all probability, by so doing, the mine might be restored to its
former flourishing state. Indéed the present workings are chiefly at
the depth of 50 fathoms. You descend into the mine in a bucket, and
the machinery for raising and elevating this bucket is very simple and
ingenious. It was constructed according to the directions of Mr. Gus-
tavus Billow, the mine-master, who informed me that he took the idea
from D’Aubuisson’s account of a similar method employed at Freyberg.
Thè number of workmen employed in the mine of Sala amounts to
2 h 2