_Method of Softening Cast-Iron_.
The following method of rendering cast-iron soft and malleable may be
new to some of your readers:--It consists in placing it in a pot
surrounded by a soft red ore, found in Cumberland and other parts of
England, which pot is placed in a common oven, the doors of which
being closed, and but a slight draught of air permitted under the
grate; a regular heat is kept up for one or two weeks, according to
the thickness and weight of the castings. The pots are then withdrawn,
and suffered to cool; and by this operation the hardest cast metal is
rendered so soft and malleable, that it may be welded together, or,
when in a cool state, bent into almost any shape by a hammer or vice.