Japanese Mines . 
[October, 
436 
and is usually of excellent quality. When properly refined 
it takes a foremost place amongst the various kinds of com- 
mercial copper, and it is almost invariably free from the 
injurious metals, such as antimony and arsenic. A brief 
account of a copper-mine in Yamato, in the neighbourhood 
of Osaka, will probably possess some interest, inasmuch as 
from various circumstances it is doubtful, in the opinion of 
the metallurgist of the Japanese Mint, whether European 
processes would profitably and successfully replace the 
native methods at present followed. This mine is situate in 
a narrow valley in the midst of mountains, and to reach it 
two passes, nearly 3000 feet high, have to be crossed. So 
narrow, indeed, is this valley, and so steep the inclination 
of its sides, that there is no level ground, nor is there ground 
which could be levelled, within nearly half a mile of the 
entrance of the mine, and all the present dressing-houses, 
furnaces, &c., are perched upon the slopes, and supported 
by built-up foundations. The levels in this mine are driven 
and the ore removed by the aid of gunpowder, and the 
pieces broken down are carried to the surface on the backs 
of men and women. The ore, having been broken up into 
pieces about the size of walnuts, is placed, with a sufficiency 
of wood, in kilns 5 feet square, with walls rudely built of 
stone and lined with clay. The calcination lasts fifteen 
days, but is of a very unsatisfactory character, much of the 
ore undergoing but slight change in the process. The fur- 
nace consists of a hemispherical cavity in the ground, lined 
with refractory clay : it is furnished with two bellows at 
the back and one in front, and is half covered with a thick 
semicircular lid of clay. The process of melting is thus 
described by our authority : — The furnace, having been re- 
paired and well dried after the “ heat ” of the previous day, 
is lighted by introducing some burning embers, together 
with fresh charcoal, and over this charcoal a third part of 
the charge of ore is piled, forming a heap ; the blast from 
the bellows behind is started, and soon jets of flame of car- 
bonic oxide make their appearance over the whole surface of 
the heap, which, gradually melting, subsides into the fur- 
nace ; the slag is then removed, and another portion of 
charcoal and of ore piled up as before. When the whole of 
the charge (about 11 cwts.) has been melted down in this 
way, the slag is skimmed off ; after which the front bellows 
is brought into adtion, the blast of air being directed upon 
the surface of the molten “ regulus ” and copper, and a 
little charcoal added at the side from time to time to keep 
up the heat. In ten hours the charge is worked off. and the 
