ompete for their share of the trade; and
the extent to which it has grown, the number of furnaces constantly at
work, and the quantity of steel cast into ingots, to be tilted or
rolled for the various purposes to which it is applied, have rendered
Sheffield the greatest laboratory in the world of this valuable
material. Of the total quantity of cast-steel manufactured in England,
not less than five-sixths are produced there; and the facilities for
experiment and adaptation on the spot have enabled the Sheffield
steel-makers to keep the lead in the manufacture, and surpass all
others in the perfection to which they have carried this important
branch of our national industry. It is indeed a remarkable fact that
this very town, which was formerly indebted to Styria for the steel
used in its manufactures, now exports a material of its own conversion
to the Austrian forges and other places on the Continent from which it
was before accustomed to draw its own supplies.

Among the improved processes invented of late years for the manufacture
of steel are those of Heath, Mushet, and Bessemer. The last promises
to effect before long an entire revolution in the iron and steel trade.
By it the crude metal is converted by one simple process, directly as
it comes from the blast-furnace. This is effected by driving through
it, while still in a molten state, several streams of atmospheric air,
on which the carbon of the crude iron unites with the oxygen of the
atmosphere, the temperature is greatly raised, and a violent ebullition
takes place, during which, if the process be continued, that part of
the carbon which appears to be mechanically mixed and diffused through
the crude iron is entirely consumed. The metal becomes thoroughly
cleansed, the slag is ejected and removed, while the sulphur and other
volatile matters are driven off; the result being an ingot of malleable
iron of the quality of charcoal iron. An important feature in the
process is, that by stopping it at a particular stage, immediately
following the boil, before the whole of the carbon has been abstracted
by the oxygen, the crude iron will be found to have passed into the
condition of cast-steel of ordinary quality. By continuing the
process, the metal losing its carbon, it passes from hard to soft
steel, thence to steely iron, and last of all to very soft iron; so
that by interrupting the process at any stage, or continuing it to the
end, almost any quality of