Polynesian., 1856-11-29

turn into contact with stream OF air. i o use
the language of chemistry, energetic combina-
ton takes place between the oxygen of the air
pumped in and the carbon mixed with the iron
In popular language, fire, instead of being sup
lplied externally round about the mass of iron, Is
kindled and sustained throughout every particle Of
the liquid metal. A heat is thus generated, vast
lily greater than that which can be supplied by
mere external combustion. What is taking place
is indicated by the tongues of flame, which in
two or three minutes, begin to shoot forth from the
apertures in the vessel, and which gradually in
crease in body and in intensity until the whole
mass is in a state of agitation, almost like boiling
water-the difference being, however, that the
agitation is caused by the external force of the
air blown rapidly and continuously through the
liquid iron, not by the conversion of the substance
itself into cxpansible vapor, in the case of
genuine ebullitiOn. However, this state may
very fairly be called the boil and it is indicated
! by the blowing out through the apertures, of
large quantities of melted sag-the refuse which
! Is squeezed out of the puddler's bloom under the
action OF immense pressure, but which is here
driven off simply by the action of the blast be-
cause, being much lighter than the iron, it rises
to the top, like scum upon the surface of the
water, now that the metal is in state of perfect
fiuidity. 1t is supposed that at this period very
important change begins to take place. and that
that part of the carbon which is in a state not of
mechanical mixture, but of chemical combination
with the iron, Is now compelled, by the agency,
of the increasing heat to part from the metal, and
yield itself captive to the superior affinity of the
oxygen. This - boil' takes place from fifteen to
twenty or twenty-five minutes alter the commence
ment of the process, and continues, with more or
less violence until all the carbon is burned out
The moment that this is effected and that no more
carbon, or only very small quantity remains, the
metal must be out, otherwise the action of the
air would cool the metal, and make it set hard
with great rapidity. 1t may be run out into
molds of any size shape but the most advan-
tageUus form is that Of deep and narrow mold,
as then the Stag which has not been already re-
moved, and which comes last out of the hole at the
bottom of the converting vessel, lies in a thin cake
at the top of the casting, and is easily taken off
by pair of shears.
! 1t will be obvious that one principal feature in
the process Is, that the operator deals with the
metal in a state of perfect luidity-a desderatum
hitherto unattainable with iron cOnta ming only a
small quantity of carbon. Hence it can not mere
ly be procured in masses of any size (whereas the
lpuddler can only produce 60 or 20 lbs in lump,
but it will possess the distin gushing character of
all fluids-it will be perfectly homogeneous. The
texture, composition and quality Will be the same
throughout every part of the mass. That the
hu,dty Is really greatly increased, nOtvithstand-
ing the subtraction of the carbon, is shown by
the fact that it is found desirable to diminish the
/
pounds during the latter part of the process
as well as by the rapidity with which the metal
runs out of the furRanCe, and It's brilliant white
ness. Ii Is impossible to Overrate the advantage
of having a really homogeneous product. In large
masses of maleable iron, procured IN the ordna-
ry way by welding together a number OF the pad-
der's blooms there often occur small knobs and
fragments of metal much harder than the rest; and
many manufacturers consider soft malleable iron
quite as trying to their tools hard steel, from
the unexpected increase of resistance suddenly
offered by particular parts Of the mass and cOnse
quent unequal strain upon dihcren; portions of the
machinery. The greater the mass required, the
greater the difficulty of obtaining metal upon all
parts Of which equal reliance can be placed and
hence, where a very heavy strain, in direction
different from that Of the FIBRE Is expected strength
is often obliged to be sought in an enormous thick
ness of material. The prodigious weight of an
chors is rendered necessary by the imposSlbllIty
of calculating accurately the strength OF the met
al in any particular part, that the size of the
whole must be increased 10 meet the chance of
bad piece of metal occurring here and there. One
of Mr. Bessemer's numerous patents Is for the
application of his invention to the construction OF
anchors, in which he hopes to attain an equal
strength with greatly diminished weight.
1t is hardly necessary to point out the enormous
saving in labor and fuel effected by the new pro-
cess, especially in the manufacture of steel Mr..
Bessemer believes that steel, such as is now worth
from ESQ to ESQ tun, may be produced at a cost
to the manufacturer of less than Gl0 tun. In
the manufacture of maIleabe irOn also the
ing will be very great, though less than in the
case of steel. Indeed, one of the results of the
invention will be the curious anomaly that steel
will be produced at little less risk and therefore
at a little less COST than malleabe iron; for it is
obvious that, by tapping the furnace tJOre the
complete combustion of the carbon has taken
place, steel will be produced instead of iron.
Practice and experience will, no doubt, IN time
enable the workmen so to regulate the operation
as to produce to a nicely any particular quality of
iron or steel required; but until this practical
knowledge has been gained, there will be some
difficulty in calculating the exact length of time TO
be occupied in the conversion. If, therefore, the
process should be continued a little too long for
steel, malleable iron will be obtained-if 1t be
continued little too long for malieabe iron, the
metal will be set in the furnace. "The boil" ap-
pears to be the critical period. Whatever be the
time occupied in arriving at the BOIL 1t Is found
that from twelve TO fifteen minutes are requisite
to produce maeable irOn and from seven to twelve
minutes to produce the different qualities of steel.
How effectually the carbon can be removed is
shown by an analysis of a chance specimen Ot Mr..
Bessemer's ma9able iron, made by DIR. Henry, /
who. we believe was strongly inclined to doubt
whether the process could really be so successful
as it was stated to be. He found the quantity of
carbon present 10 be less than I-3Oth per cent-or
less than I-O0Oh part of the weight Of the medal.
Of silica, trace merely found. By the aPpli-
cation of means already well understood, the sui
phur and phosphorus will be as completely remov-
ed A considerable portion of both is driven off
without the use of any means for that special obect
and by treating the melted metal with proper sub
stances. these impurities will be Withdrawn. The
difficulty which Mr. Bessemer has applied himself
to solve. and which he has solved, is the complete
of carbon and the earthly bases. Apart
from the cheapness and facility of his process, he