of rocks which runs along the north side of the southernmost lake.
The rocks in this tract consist of mica slate. In these rocks there
occur various veins of copper pyrites and magnetic ironstone, commonly
separate, but in some o f the veins occurring together. These
veins constitute the mines which are wrought in this tract.
In these mines there occurs a kind o f white cobalt ore, consisting
o f cobalt, iron, arsenic, and sulphur; though I do not know that it
has ever been accurately analysed.
Fluor spar occurs in the same place, not crystallised, but compact,
and varying in colour; being found white, violet, and emerald
green.
There occur also specimens of coalblende, consisting o f about one
part coal, and three parts earth and oxide of iron. Hence it does not
readily burn, unless it be heated with saltpetre.
Sparry iron ore likewise occurs, which was analysed by Hisinger,
and found to consist o f the following ingredients:
Oxide of iron............................. 63-25
Oxide of manganese . . . . . . . . 3
L im e ............. ............................ l
Carbonic acid............................. 30
W a te r ........................................ 175
99
Loss................................... 1
100
Sulphuret of bismuth likewise occurs in quartz, and in no great
quantity.
In this tract there are no fewer than twenty-seven mines, either at
present in existence, or which have been formerly wrought. They
are all either iron or copper mines.
The minerals that occur in the copper mines of Bastnas are the
following: asbestus, actinolite, petroleum, pyrites in octahedral crystals,
sulphuret of bismuth, molybdena, wolfram a species o f cobalt
ore, which was analysed by Hisinger, and found to contain the following
constituents:
Cobalt......................................... 43-20
Copper 14-40
I ro n ....................................... 3-S3
Sulphur.......................... 38-50
E a r t h . ; . . . . . . . . , . . . . . . . 0-33
99'96
But the most remarkable mineral which is found in this mine is the
cerite, a mineral first noticed by Bergman, and conceived by him to
belong to that called tungsten, and composed of tungstic acid and
lime. Eluyart analysed it, and showed that it was not tungsten. No
attention was paid to it for many years, till at last it was analysed by
Klaproth, and by Hisinger and Berzelius nearly about the same time.
Klaproth discovered in it a new substance, which he considered as an
earth, and to which he gave the. name ockroita. Hisinger and Berzelius
discovered in it a new. substance, which they conceived to be
a metallic oxide,: to which .they, gave the name of cerium. Their
results were confirmed by Yauquelin, and have been adopted by
chemists. I shall here state the result of the different analyses of this
substance which have been hitherto made, observing, that the differences
in the proportions are most probably owing to the foreign substances
with which the cerite is always more or less mixed.
According to Klaproth’s analysis, the constituents are,
Ochroita.............................. . 54"5
Silica ................ 34
Oxide o f iro n ........................ 4
W a te r ..................................... 5
L o s s ......................................... 2-5
loo-o