1to the ore which has
been roasted, while it is still hot, in order to make
it softer and more easily broken; for after fire has dried up the moisture
in the ore, it breaks up more easily while it is still hot, of which fact burnt
limestone affords the best example.
it softer and more easily broken; for after fire has dried up the moisture
in the ore, it breaks up more easily while it is still hot, of which fact burnt
limestone affords the best example.
By digging out the earth they make the areas much larger, and square;
walls should be built along the sides and back to hold the heat of the
fire more effectively, and the front should be left open. In these compart
ments tin ore is roasted in the following manner. First of all wood about
twelve feet long should be laid in the area in four layers, alternately straight
and transverse. Then the larger pieces of ore should be laid upon them, and
on these again the smaller ones, which should also be placed around the sides;
the fine sand of the same ore should also be spread over the pile and pounded
with shovels, to prevent the pile from falling before it has been roasted; the
wood should then be fired.
walls should be built along the sides and back to hold the heat of the
fire more effectively, and the front should be left open. In these compart
ments tin ore is roasted in the following manner. First of all wood about
twelve feet long should be laid in the area in four layers, alternately straight
and transverse. Then the larger pieces of ore should be laid upon them, and
on these again the smaller ones, which should also be placed around the sides;
the fine sand of the same ore should also be spread over the pile and pounded
with shovels, to prevent the pile from falling before it has been roasted; the
wood should then be fired.
A—LIGHTED PYRE. B—PYRE WHICH IS BEING CONSTRUCTED. C—ORE.
D—WOOD.
E—PILE OF THE SAME WOOD.
E—PILE OF THE SAME WOOD.
Lead ore, if roasting is necessary, should be piled in an area just like the
last, but sloping, and the wood should be placed over it. A tree trunk should
be laid right across the front of the ore to prevent it from falling out. The
ore, being roasted in this way, becomes partly melted and resembles slag.
last, but sloping, and the wood should be placed over it. A tree trunk should
be laid right across the front of the ore to prevent it from falling out. The
ore, being roasted in this way, becomes partly melted and resembles slag.
zoom in
zoom out
zoom area
full page
page width
set mark
remove mark
get reference
digilib