1.--_Memorial of the workers in iron of Philadelphia,
praying that the present duty on imported iron may be
repealed, &c._
2.--_Report of the Select Committee (of the Senate of the
United States,) to whom was referred "the petition of
upwards of three hundred mechanics, Citizens of the City and
County of Philadelphia, employed in the various branches of
the manufacture of iron," and also, the petition of the
"Journeymen blacksmiths of the City and County of
Philadelphia, employed in manufacturing anchors and chain
cables."_
3.--_Report of the minority of the Select Committee on
certain memorials to reduce the duty on imported iron._
4.--_Remarks of the majority of the Select Committee on the
blacksmiths' petition in reply to the arguments of the
minority._
5.--_Manuel de la Metallurgie de fer par_ C. I. B. KARSTEN,
_traduit de l'Allemand, par_ F. I. CULMAN, _seconde edition,
entierement refondue, &c._ 3 vols. 8vo. pp. 504, 496, & 488.
Mme. Thirl: 1830: Metz.
6.--_Voyage Metallurgique en Angleterre, par_ MM. DUFRENOY
_et_ ELIE DE BEAUMONT. 1 vol. 8vo. pp. 572. Bachelier:
Paris: 1827.
The discussion contained in the petitions and legislative reports which
we have prefixed to this article, is one of the most powerful interest,
not merely to those concerned in the manufacture of iron, and the
articles of commerce of which it is the material, but to the whole
community. Iron, if the cheapest and most abundant, is intrinsically the
most valuable of the metals. It may supersede, and gradually has, in its
applications, superseded the greater part of the rest, and has taken the
place of wood and stone in a great variety of mechanical structures; it
is indispensable in the modern arts of the attack and defence of
nations; and its possession is the distinctive difference between
civilized man and the savage. Well was it said to Croesus exhibiting his
golden treasures, that he who possessed more iron, would speedily make
himself master of them, and the truth of the maxim was even more
powerfully verified, when the accumulated riches of the Aztecs and Incas
were acquired at the cost of a few pounds of Toledo steel.
When we compare the state of manners and arts of the Mexicans and
Peruvians with that of their Spanish conquerors, we are almost compelled
to admit, that the possession of iron was perhaps the only real
superiority in civilization which the latter possessed. Gunpowder played
but a small part in the contests where handfuls of men routed myriads;
the courage of the Indian warrior is not less firm than that of the
descendant of the Goths.
The sciences and arts which are now the boast of European civilization,
were then but awakening from a slumber of ages; in the latter, the
workmanship of Europe was in many instances inferior to that of the new
world, and in the former, to take as an instance that which occupies the
highest place, astronomy, the civil year of the Mexicans was
intercalated and restored to the solar, by a process more perfect than
that we even now employ; and the latter was not introduced into Europe
until half a century after the throne of Montezuma fell. The bloody
human sacrifices which excited to such a degree the abhorrence of the
conquerors, were not greater marks of savage cruelty, than were their
own _auto da fes_, and the tortures inflicted on Guatemozin. Yet if not
superior in bravery, in the arts, the sciences, and the more distinctive
attribute of civilization, humanity, the possession of iron was
sufficient to ensure the triumph of the Spaniards.
Of all the metallurgic arts, that by which iron is prepared from its
ores, demands the greatest degree of practical skill, and is the most
difficult to bring to perfection. Although ages have elapsed since it
first became an object of human industry, its manipulation and
preparation are yet receiving improvements, while those of the other
ancient metals appear hardly susceptible of modification or advancement.
Copper and its alloys, tin, lead, and mercury, were as well and as
cheaply prepared by the ancients as by the moderns; and the reduction of
the precious metals has received no important change, since the process
of amalgamation was first applied to them,--while the preparation of
iron is daily improving under our eyes, and its cost diminishing. It may
even be doubted whether the iron we first find mentioned in history, was
an artificial product, and not obtained from the rare masses in which it
is found existing in the native state, and which are supposed to be of
meteoric origin.
The original use of iron is ascribed in the sacred writings to Tubal
Cain, who lived before the flood;--but we have no proof that he did not
employ a native iron of this description. Be this as it may, the united
testimony of antiquity exhibits to us an alloy of copper used for the
purposes to which we apply iron, and the latter metal as comparatively
scarce, and of high value. The qualities of iron were known and
appreciated, but the art of preparing it was not understood. The reason
is obvious; those ores of iron which have an external metallic aspect,
are difficult of fusion and reduction, those which are more readily
converted, are dull, earthy in their appearance, and unlikely to attract
attention,--while gold and silver manifest in their native state their
brilliant characters, and the ores of copper and lead exhibit a higher
degree of lustre than the metals themselves.
If, then, history does not show us the ancient nations employing iron
for their arms and instruments, it is because they were unable to
prepare it. Even in the middle ages, we find copper in use for arms,
because the nations that employed it, could not conquer the difficulties
that attend the preparation of iron.
The books of Moses, however, show that iron was known at that era to the
Egyptians, and the distinction he draws between it and brass, seems in
favour of our view of the origin of that which was then employed. The
stones of the promised land were to be iron, but brass was to be dug
from the hills. Twelve hundred years before Christ, if we receive the
testimony of Homer, who, if he be rejected as an historian, must still
be admitted as a faithful painter of manners. The Greeks used an alloy
of copper for their arms, but were unacquainted with iron, which they
estimated of much higher value.
Autar Peleides thechen solon autochoonon,
hon prin men riptaske mega sthenos Eetionos.
Alla etoi ton epephne podarchos dios Achilleus,
Ton d aget enneessi sun alloisin chteatessin.
Ste d orthos chai muthon en Argeioisin eeipen.
Ornusth, hoi chai toutou aethlou peiresesthe!
&c. Iliad, Book XXIII, 1. 826.
From this passage and the following lines, we learn the two-fold fact:
1. That a mass of iron of no greater weight than could be used as a
quoit, by a man of great strength, was esteemed of sufficient value to
be cited as an important article in the spoil of a prince: 2. That its
use was confined to agricultural purposes, and not applied in war. Hence
the more valuable form steel, and its tempering, were unknown.
Five hundred years later, Lycurgus attempted to introduce the use of
iron, as money, into Sparta. The reasons usually cited for this act, do
not seem to apply; and we ought not to accuse that lawgiver of the want
of knowledge in political economy that is usually ascribed to him, in
endeavouring to give a base material a conventional value to which it
was not entitled. The iron was still, probably, more costly than brass,
and the error of Lycurgus did not lie in ascribing to it a value beyond
its actual cost, but in depriving it of the property of convertibility
to useful purposes, which was necessary to maintain its price.
In the construction of the temple by Solomon, 130 years before the aera
of Lycurgus, iron was employed in great abundance; and, from the cost
lavished upon that building, we are almost warranted in considering it
as still bearing a high value, even in that country, so far in the
advance of Greece in the arts of civilized life.
Herodotus ascribes the discovery of the art of welding iron to Glaucus
of Chio, 430 years before the Christian aera. But, before this period,
the Greeks had carried the art of working it into Italy, Spain, and
Africa; and the famous mines of Elba, that are still worked, were
probably opened 700 years before Christ.
It is from the working of these mines that we are to date the
introduction of iron in such abundance as to reduce its price, bring it
into general use, and finally cause it to supersede wholly the alloys of
copper. This ore is of extremely easy reduction, by processes of great
simplicity, which furnish iron of excellent quality, and are, as we
shall hereafter see, still in use. We cannot, indeed, infer with
certainty, that these were the processes used by the ancients; but their
simplicity is a strong argument in favour of their remote invention.
Steel seems to have been known as different in qualities from iron, at a
very remote period; that is to say, it was understood that there were
varieties of iron, which when tempered, became hard, whilst others
remained soft. The intentional preparation of it, as a different
species, seems to have taken its rise among the Chalybes, a people of
Asia Minor, and it was afterwards obtained from Noricum. We still find
in the latter country, (Styria,) an ore that furnishes steel, by
processes as simple as those by which the iron is obtained from the ore
of Elba, and hence can form some tolerable guess at the mode in which
the steel of the ancients was obtained.
The third form in which we find iron as an article of commerce, namely,
cast iron, is of far more recent origin. It has been traced to the banks
of the Rhine, and it is certain that stove-plates were cast in Alsace in
A. D. 1494. From this epoch, then, dates the great improvement in the
preparation of iron, by which its price has been so far lessened, as to
render it available for innumerable purposes, from which a small
addition to its present cost would exclude it.
* * * * *
Iron, as may be inferred from what has been stated, is known in commerce
in three distinct forms--wrought or bar iron, cast or pig iron, and
steel. The received chemical theory on this subject is, that the former
is metallic iron nearly in a pure state, and that the two latter are
chemical compounds of iron and carbon. How far this is true will be
examined in the sequel.
When wrought iron is nearly pure, it has, when in bars of not less than
an inch square, or plates not less than half an inch in thickness, a
granular structure. From the appearance of these grains, an estimate may
be had of its quality; grains without any determinate form, neither
presenting, when broken, crystalline faces, nor arranging themselves in
plates; and which, in the fracture of the bar, exhibit points, and even
filaments, manifesting the resistance they have opposed, are marks of
the best quality. If, when broken, a crystalline character is exhibited,
the quality is bad, and will, according to a disposition difficult to
describe in words, either break under the hammer when heated, or be
subject to rupture when cold. These two opposite defects are, in the
language of our manufacturers, called red and cold short, or shear. The
former fault unfits it for being easily worked; the latter destroys its
most important usefulness. When the manufacture has been badly
conducted, crystals will appear mingled with tenacious grains, and a
want of uniform consistence will render it unfit for being cut and
worked by the file. Iron of the latter character may, notwithstanding,
possess great tenacity.
In still smaller bars, good iron, in breaking, exhibits filaments like
those shown by a piece of green wood when broken across; this is
technically called nerve; and as it does not show itself in larger bars,
it has been supposed that it is the result of the process of drawing out
the bars. This is partially true, although the iron that presents a
crystalline structure will not acquire nerve, however frequently
hammered. To obtain nerve in larger masses, it is necessary to form them
of bundles of smaller bars, a process known under the name of faggoting.
* * * * *
Iron contains in its ores many impurities of different natures,
according to circumstances, and is in its preparation exposed to several
others; by these its quality is frequently much affected. Its valuable
ores all contain the iron in the state of oxide. The oxygen, it is
generally believed, is not wholly separated even in the best malleable
iron, but enough still remains to impair in some degree its good
qualities. In its manufacture it is exposed to the action of carbon,
with which it is capable of combining. Much iron appears to contain some
of the combinations of this sort, existing in the form of hard
particles, technically known by the name of _pins_.
Of inflammable bodies, sulphur and phosphorus are frequently contained
in the ores of iron; and when pit coal is used in the manufacture, the
former substance is present, and may influence the product. The union of
sulphur, in very small quantities, with the iron, creates the defect
called red short, although it is probably not the only substance that
produces the same fault; but when it is caused by sulphur, all the good
properties of the iron are impaired, which is not always the case when
it arises from other impurities. The defect of breaking when cold, has
been attributed to the presence of phosphorus by high authority. There
are, however, ores in this country, containing a phosphate of lime,
which yield iron of excellent quality.
A mixture of sulphur and carbon deprives iron of its property of
welding, and in the highest proportion gives the opposite defects of
being both red and cold short.
Ores of iron contain the earths, silex, alumina, lime, and magnesia.
With the bases of these earths the metal is capable of forming alloys;
those of the three first are often thus combined. Silicium has been
discovered combined with iron to the extent of 3-1/2 per cent. It has
been found to render this metal harder, more brittle, and more similar
in structure to steel; so small a quantity as 1/2 per cent. has been
sufficient to render it liable to break when cold; and it appears
probable, that by far the greater part of the cold short irons owe this
fault to the presence of silex, rather than to that of phosphorus. Iron
obtained from the ores by means of coal, is, under circumstances of
equality in other respects, more likely to be combined with silicium
than when made with charcoal. Karsten infers that a combination with
aluminum produces similar defects, and denies the assertion of Faraday,
that the good qualities of a steel brought from India are due to an
alloy with this earthy base. A combination with the metallic base of
lime, lessens the property that iron possesses of being welded, but does
not render it more liable to fracture, either under the hammer or when
cold.