which, through a trough bringing it from the
blast-furnace, the cast iron can pour in a
white hot torrent. Establish the blast first,
then pour the torrent in. The air leaps up
through it, dashes it up and down, and,
mingling with the metal, ultimately gives up
its oxygen to the carbon, which begins to
burn. Flame, mixed with some bright
sparks, rises through the furnace-mouth.
The combustion is attended with increase of
heat, and, the heat being generated in the
interior of the mass and dispersed through it
in innumerable fiery bubbles, most of it is
absorbed by the metal, of which the
temperature is thus very greatly raised. In a
quarter of an hour or twenty minutes, all
the carbon that had been mixed only
mechanically with the iron is consumed; the
temperature of the molten iron has in the
mean time risen to so high a point, that the
carbon chemically combined with it breaks
from its old tie to burst into flame with the
oxygen. A sudden increase in the volume
of flame rising from the furnace, indicates
when this stage of the operation has
commenced. The metal now rises above its
former level, and a light frothy slag makes its
appearance and is thrown out in foamy masses.
This eruption lasts five or six minutes and
then ceases. A steady and powerful flame
now burns, indicating, after the period when
impurities could be no longer retained, a
constant combustion of the carbon and
consequent decrease of its quantity; the heat of
the entire mass, for the reason before stated,
all the while rising. The temperature is so
great that oxide of iron as fast as it forms
fuses, and so forms a solvent of the earths
that have to be got rid of; the sulphur is
burnt off, and, by the violent ebullition, the
whole mass is in this way thoroughly
cleansed. The tedious work of the refiner
and the puddler is now to be considered done
in little more than half-an-hour, by chemical
changes, set on foot and maintained simply by
blasts of air. The vent-hole being opened,
and the metal poured out, it is found, when
cool enough to be weighed, to have lost
eighteen per cent, where it would have lost
twenty-eight per cent, by the old process; it
proves also to be more free from cinder and
impurity than the old puddle bars; to require
very much less subsequent working; and to
yield its produce to the roller in large
masses, free from sand-crack or flaw.

By the puddling process four or five
hundred pounds of metal were all that could be
operated upon at one time, and this was
treated in portions of seventy or eighty
pounds watched over by human labour,
painfully manipulated and stamped into form.
There is no limit to the size of the
homogeneous mass produced by Mr. Bessemer's
new method, except the size of the cupel, or
refining furnace. In the experiments with
which this theory has been demonstrated,
from three to five tons of crude iron have
passed into the condition of piles of malleable
iron, in thirty or five and thirty minutes,
and, except the coke used in the first smelting,
the metal has been brought into contact
with no fuel but the charcoal contained in
itself.

Once brought to a white heat, the metal,
with the help of the air-blast, can go on
alone; and it will go on, as it continues to
lose carbon, through the successive stages of
ordinary cast steel, hard steel, soft steel,
steely iron, and soft iron. The quality of
metal obtained will depend, therefore, upon
the period at which it is thought proper
that the vent-hole of the cupel should be
opened. There is one particular quality
midway between the qualities of cast steel and
soft malleable iron, which Mr. Bessemer calls
semi-steel: more tensile, harder, and more
elastic than soft iron, at the same time not so
brittle or so difficult to work as steel: which
he believes will rise into great importance
for its lightness, strength, and durability,
It will be also the cheapest form, of metal
known.

The finest qualities of iron which are still
imported from abroad, and sold at from
twenty to thirty pounds a ton, Mr. Bessemer
is firmly assured he can produce, of equal
quality, at a cost of two pounds a ton below
that of the common English iron.

At present, iron in very large masses, is to
be obtained only by welding; and the affinity
of hot iron for oxygen is so great, scales
form so instantly, that it is most difficult so
to weld as to produce perfect union. This is
one source of the flaws which destroy the
value and sometimes the use of heavy guns
and other great works from the foundries.
If the new invention answer the hope of its
projector, all necessity of welding will be
superseded; the best iron may be had in
uniform mass—practically speaking, we might
say, of any required size.

To fulfil, only in part, expectation of this
magnitude, is to effect a vast change for the
better in one of the most vital conditions of
the progress of this country, and of human
civilisation.

Demonstrations by experiment are now
being made in London: necessarily somewhat
imperfect, because London has no blast-
furnaces of any size: but they are made
apparently with most complete success. It
is objected by practical men that Bessemer's
Process does produce very promptly
and cheaply, malleable iron,—so much it is
now impossible to deny—but that it is not
fibrous enough to be worth anything. Heads
have been shaken on 'change at Birmingham,
over a rod of Bessemer iron, rolled and broken,
and it has been pronounced Red Short. On
the other hand it is declared that iron
produced by the new process at Woolwich, has
stood its tests, and proved as fibrous as could
be desired for any purpose.  Of the difficulties
raised by practical men, against the possibility