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B.—Plagionit or Rosenit in granular aggregates or amorphous masses of a dark black grey colour.
J.—Hetermorphit or Antimony feather-ore in fibrous aggregates of a dark grey colour.
All these minerals contain lead, antimony and sulphur as chief elements; often some iron and other impurities. They seem to he found at very many places in Japan. We received samples from Higo: Ohobata; Higo: Hitoyashi; the island of Amakusa; Hiüga and Satsuma. These ores have no practical value, because it is too difficult to separate the lead from the antimony by melting, and also because lend and antimony are found in better minerals, as galena and antimony glance.
Metallurgy of Lead.
The galena is first separated by mechanical treatment from the foreign stones, afterwards coarsely powdered and heated in a globular loamy furnace, the interior sides of which are covered with a layer of fine proof clay. The bottom of this furnace inclines conically, so that the smelted metal runs to the point in the midst and can be received there. The tubes of two bellows reach through opposite openings in the side of the furnace. Wood is used as fuel. When the galena is fused, it is converted by the air of the bellows, partly into sulphate of lead and partly into lead metal, whilst a portion of the sulphur escapes together with the products of combustion, as sulphurous acid. Immediately afterwards this portion of metallic lead acquires oxygen and is thus converted into oxide of lead. Another portion of the galena remains unaltered. After this roasting process the second operation commences. A fresh supply of fuel is thrown into the furnace causing a greater heat in order to convert both the sulphate of lead and the sulphide of lead into metallic lead and sulphurous acid. The fluid metal is then collected into the receiver and cooled. The lead thus obtained is very impure and contains still a large amount of oxide of lead and some sulphide of lead. It is smelted therefore again in a smaller furnace with some charcoal, in order to reduce the oxide of lead. The sul-
