1teeth,
and now again levelled down with a hoe, both of which are made of iron.
The very fine tin-stone requires to be burned less than that of moderate size,
and this again less than that of the largest size. While the tin-stone is being
thus burned, it frequently happens that some of the material runs together.
The very fine tin-stone requires to be burned less than that of moderate size,
and this again less than that of the largest size. While the tin-stone is being
thus burned, it frequently happens that some of the material runs together.
A—FURNACE. B—ITS MOUTH. C—POKER. D—RAKE WITH TWO
TEETH. E—HOE.
The burned tin-stone should then be washed again on the strake, for in this
way the material which has been run together is carried away by the water
into the cross-trough, where it is gathered up and worked over, and again
washed on the strake. By this method the metal is separated from that
which is devoid of metal.
The burned tin-stone should then be washed again on the strake, for in this
way the material which has been run together is carried away by the water
into the cross-trough, where it is gathered up and worked over, and again
washed on the strake. By this method the metal is separated from that
which is devoid of metal.
Cakes from pyrites, or cadmía, or cupriferous stones, are roasted in
quad
rangular pits, of which the front and top are open, and these pits are generally
twelve feet long, eight feet wide, and three feet deep. The cakes of melted
pyrites are usually roasted twice over, and those of cadmía once. These latter
are first rolled in mud moistened with vinegar, to prevent the fire from con
suming too much of the copper with the bitumen, or sulphur, or orpiment, or
realgar. The cakes of pyrites are first roasted in a slow fire and afterward in
a fierce one, and in both cases, during the whole following night, water is let in,
rangular pits, of which the front and top are open, and these pits are generally
twelve feet long, eight feet wide, and three feet deep. The cakes of melted
pyrites are usually roasted twice over, and those of cadmía once. These latter
are first rolled in mud moistened with vinegar, to prevent the fire from con
suming too much of the copper with the bitumen, or sulphur, or orpiment, or
realgar. The cakes of pyrites are first roasted in a slow fire and afterward in
a fierce one, and in both cases, during the whole following night, water is let in,