D. S. (David Samuel) Margoliouth.

The Popular science monthly (Volume 19) online

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So far the difference between iron and steel has seemed to be
merely one of degree, depending on the amount of carburization.
The methods we have considered are, in fact, only modifications of
those practiced for the production of malleable iron. AVe will now
consider the different processes that have for their object to impart a
certain amount of carbon to malleable iron. The Hindoos have prac-
ticed one of them from time immemorial. They place in unbaked-clay
crucibles, of the capacity of a pint, a piece of malleable iron, some
chopped wood, and a few leaves of certain plants ; the top of the crucible
is then closed with clay, and the whole well dried near a fire. A num-
ber of these crucibles are then strongly heated for about four hours in
a cavity in the ground, by means of charcoal and a blast of air forced
in by a bellows. There is some reason to believe that an excess of car-
bon, over that required to produce the hardest steel, has to be added,
in order to fuse the metal at the temperature which can be commanded
in these furnaces. Before being drawn out into bars, the cakes of
metal obtained in this way are exposed in a charcoal-fire during sev-
eral hours to a temperature a little below their melting-point, the blast
of air playing upon them during the time. The object of this is,
doubtless, to remove the excess of carbon.

In 1800 a patent was taken out by David Mushet for a process in
every respect analogous to that just referred to. He appears, how-
ever, to have applied it to the manufacture of a metal low in carbon,
and therefore intermediate between iron and steel, partaking in a cer-
tain degree of the properties of both.

In another method referred to by Biringuccio, in 1540, steel was
produced by keeping malleable iron in molten cast-iron until it be-
came pasty, and on examination was found to possess the properties
of steel. In connection with the theory of steel manufacture this
process is of great interest. It shows that iron in a strongly heated
tondition is capable of absorbing carbon by direct contact, unless we
suppose that the carburization is effected by dissolved gases, which is

In the cementation process, which was well described by Reaumur,
in 1722, bars of iron are kept at a glowing red heat, surrounded with
charcoal in boxes, into which the air is prevented from entering. The
operation lasts from seven to ten days, according to the quality of
steel required. These bars are never uniformly carburized, and, be-
sides, they contain cinder, as the metal has never been fused. The


process had been a long time in use, however, before it occurred to
any one to fuse the steel and make it homogeneous. This was done by
Huntsman, about 17G0.

By all the processes we have so far reviewed, good steel could be
produced, but only in small quantity and at great expense. The ap-
plications of steel were, in consequence, very limited ; in fact, prac-
tically, its use was confined to implements with a cutting edge.

In 1845 Heath patented a process which, had it been successful,
would have given him the power of producing steel in quantity. He
proposed to melt scrap-iron in a bath of molten pig iron in a reverber-
atory furnace heated by jets of gas. There were two conditions
wanting in this method, which caused it to be a failure, viz., a suffi-
ciently high temperature, and the power easily to regulate the charac-
ter of the gases employed. Nevertheless, in this suggestion is to be
found the germ of one of the two most important processes of the
present day.

The dominant idea in treating cast-iron for steel had always been
to refine the metal by the action of atmospheric air, and this was
effected by causing a current of air to impinge upon the surface of
the metal, by means either of a blowing apparatus or the drawing
action of a chimney-stack. "What more natural than that it should
occur to some one to refine iron by blowing air into it, instead of
merely on to its surface ? We find that this idea did occur to several
persons, widely separated, in the year 1855.

In this year a patent was taken out by John Gilbert Martien for
refining iron, by forcing air through it as it flowed from the blast-
furnace, or cupola, along runners to the puddling-furnace. The proc-
ess, as detailed in the patent, was impracticable, and showed internal
evidence of not having been worked out on a manufacturing scale.
Just after this patent was taken out, we find George Parry, of the
Ebbw Yale Works, making the experiment of forcing air through
molten cast-iron, on the bed of a reverberatory furnace, by means of
perforated pipes imbedded in the fire-clay bottom. Vigorous action
is said to have taken place ; but the metal, through an accident,
escaped from the furnace, and the further trial of the process was dis-
couraged by the managing director. Two or three months after these
experiments, Henry Bessemer took out his now celebrated patent for
the production of cast-steel by blowing air through molten cast-iron ;
it should be clearly borne in mind that he had been, for a considerable
time previously, engaged in experiments on the subject. He first car-
ried out his process in crucibles, placed in furnaces, and so arranged
that the contents could be tapped from the bottom into molds.
Steam or air, either separately or together, and by preference raised
to a high temperature, was forced down into the crucible through a
pipe. The patent goes on to state that steam cools the metal, but air
causes a rapid increase in its temperature, and it passes from a red to


an intense white heat. Bessemer at first used extraneous heat to start
the process, if not, indeed, during its progress, which shows that he
was not then aware that the heat created by merely blowing in air
would be sufficient. In his next patent he dispensed with the furnace
around the crucible, and, instead of tapping the crucible from the bot-
tom, he mounted it on trunnions, and, by tipping it up by machinery,
poured the contents fi'om the mouth. This apparatus is essentially
the same as that used at the present day. It was soon found that, to
produce steel by this process which would work properly, manganese,
if not originally present, would have to be added. In the absence of
manganese, sulphur and oxygen, in anything more than very minute
quantities, make the steel crumble when worked at a red beat ; it is
said to be " red short." In the case of the oxygen, the manganese
combines with it, and passes it into the slag ; but with sulphur the
reaction is different ; its injurious effect is simply counteracted by the
manganese : it is not removed from the steel. At first manganese was
only employed in the form of spiegeleisen ; but this use was liable to
the difficulty that if enough spiegel was added to impart the requisite
quantity of manganese, too much carbon would have been introduced,
and alloys richer in manganese — known as ferro-manganese — have
been sought and found.

By adding at the end of the process a known quantity of spiegel
or ferro-manganese, containing a knoAvn quantity of carbon, steel of
any required hardness could be obtained.

The year which saw the birth of the Bessemer process was doubly
remarkable, for it was at that time that the regenerative system of
heating was first introduced by Dr. Siemens. Nothing can be simpler
than the principle involved in this method, yet it was destined to play
a most important part in the progress of the arts. The idea was to
store up the heat escaping in the waste gases from furnaces, and to
employ it to raise the temperature of the gas and air previous to their
combustion in the furnace. This was accomplished by causing the
spent gases to pass through two chambers filled with loose brickwork.
When these chambers have become heated to a high temperature, the
waste gases are made to pass through two other similar chambers, and
the air and gas necessary for combustion in the furnace are caused to
pass through the highly heated regenerators. By causing the ingoing
gases to pass alternately, at suitable intervals of time, through each
pair of regenerators, a very high and, at the same time, uniform tem-
perature can be obtained in the furnace, without any greater con-
sumption of fuel than in the older methods. The success of this
process depended entirely on the fuel being first converted into a
combustible gas. This was done in a chamber to which only sufficient
air is admitted to convert the carbon into carbonic oxide, which is
then conducted by tubes to one of the regenerators to be heated, and
thence to the furnace, where, coming in contact with air which has


been passed through the other regenerator, it burns, giving out in-
tense heat.

There are two methods now in use for the production of steel in
the reverberatory furnace, or open-hearth, as it is called. In France,
pig-iron and scrap-steel are fused together ; in England, pig-iron is de-
carburized by means of iron-ore, some scrap, however, being generally
added for the sake of utilizing it. As in the Bessemer process, the
necessary amount of carbon is imparted to the metal by the means of
spiegeleiscn or ferro-manganese. This process has been largely em-
ployed for the production of ship and boiler plates. It has the great
advantage that the metal can be kept fluid on the hearth, and its com-
position adjusted until it is exactly that required.

In 187G a patent was taken out by M. Pemot, in which it was
proposed to produce steel on an open-hearth furnace with a revolving
bed, inclined at an angle of 5° or 6° to the vertical. Pig-iron previ-
ously heated to redness is placed in the bed of the furnace and covered
with scrap-steel. The bed of the furnace is then made to revolve
slowly, the pig gradually melts, and the scrap is alternately exposed
to the strong heat of the flame, and then dipped under the molten pig-
iron. In this way the fusion is very rapid, comparatively, the whole
mass becoming fluid in about two hours. The process is then com-
pleted in the ordinary way. M. Pemot informs me that he has just
taken out a patent for an arrangement of his furnace by means of
which he can employ gas under pressure, and that within the last few
months he has obtained by this means results which have never been
equaled before.

The Ponsard furnace aims at combining the advantages of the
Bessemer and open-hearth processes. The furnace is so arranged that,
by giving it a half-revolution on its oblique axis, the tuyeres with
which it is supplied may be brought either beneath or above the sur-
face of the bath of metal. By these means the metal can be rapidly
decarburizcd nearly entirely, as in the Bessemer converter, and then,
by removing the tuyeres from beneath the metal, the final adjustment
of the carbon can be made as in the Siemens process. The rapid de-
struction of the tuyeres which is effected is a formidable obstacle to
the practical success of this process.

The one important drawback to the Bessemer process was that
phosphorus was not in any degree eliminated by it. Notwithstanding
this, enormous quantities of steel were made by it ; and, within the
last three years, means have been devised in the Thomas-Gilchrist, or
"basic" process, by w^hich this difliculty has been overcome. In the
ordinary Bessemer converter the lining was formed of ganistcr, a
siliceous material, the chemical effect of which was to prevent the
elimination of phosphoric acid. Messrs. Thomas and Gilchrist sought
a basic material which they could substitute for the ganister, and
found a magnesian limestone which worked very satisfactorily. The


result of the application has been, that phosphorus has been converted
from an enemy into a friend, and aids in producing and maintaining
the temperature that is needed. Silicon is also useful as a combus-
tible, and in preventing the metal from becoming honeycombed by
escaping gases while solidifying. This it does by combining with
oxygen and preventing the latter substance from combining with car-
bon and forming a gaseous product.

In consequence of the extremely high temperature which we can
command, either in the Bessemer or open-hearth process, it is possible
to obtain in a molten state a metal practically free from carbon, or
containing carbon to any required amount. All of the products have
been called steel, although they constitute in effect a new metal, hav-
ing qualities considerably different from those of steel.

It thus has resulted that we speak of steel ships, steel boilers, and
steel rails. The metal of which ship-plates are made contains about
yV\ per cent, of carbon, that for boilers about -f^, while rails usually
have about -^. The first and the second could not be appreciably
hardened, and the third is considerably below what would formerly
have been considered steel.

At present there is but one sound reason why steel should not
universally replace iron with advantage, and that is, that in some
cases it is cheaper to employ iron. Statistics show us that the enor-
mous quantities of steel now manufactured have but little, if at all,
affected the production of wrought-iron. It is, however, I am con-
vinced, but a question of time. When the day comes — and every day
brings us nearer to it — when steel will be manufactured as cheaply as
iron, then will wrought-iron be a thing of the past among the great
civilized nations.

One word as regards the employment of steel made by these mod-
ern methods for cutlery. Cutlery-manufacturers would tell you that
it is useless for the purpose ; nevertheless, on the Continent, it is very
largely used, and in this country to a considerable extent. I do not
hesitate to assert that, with suitable ores and proper care in the manu-
facture, steel Avell suited for cutlery can be made both in the open-
hearth and the converter. The essential in the ore is that it should
not contain phosphorus ; with but a trace of phosphorus precent, a
good cutting edge could never be obtained.

If we glance back for a moment to review our history, we shall
see that the open-hearth processes embody the same principle as the
first process by which steel was produced, viz., the mutual action of
carburized iron and oxide of iron on one another, and the Bessemer
process is, after all, though a splendid offspring, only the natural de-
scendant of the finery process, the origin of which, as we have seen,
was due to modifications in the primitive blast-furnaces. There is
perfect continuity throughout, and, after all, what more natural ?




I HAVE now presented some of the most curious and interesting
facts concerning the intelligence of ants in general ; I shall next
proceed to state some of the more remarkable facts concerning the
intelligence of certain species of ants in particular.

Leaf-cutting Ants of the Amazon. — The mode of working prac-
ticed by these ants is thus described by Bates :

Tliej mount a tree in rrmltitudes. . . . Each one places itself on the surface
of a leaf, and cuts with its sharp, scissors-like jaws a nearly semicircular incision
on the upper side ; it then takes the edge between its jaws, and by a sharp jerk
detaches the piece. Sometimes they let the leaf drop to the ground, where a
little heap accumulates, until carried off by another relay of workers ; but gen-
erally each marches off with the piece it lias operated on, and, as all take the
same road to the colony, the path they follow becomes in a short time smooth
and bare, looking like the impression of a cart-wheel through the herbage.

Other observers have since said that this herbage is regularly felled by
the ants in order to make a road. Each ant carries its semicircular
piece of leaf upright over its head, so that the home-returning train is
rendered very conspicuous. Keener obser^-ation shows that this home-
returning, or load-carrying, train of workers keeps to one side of the
road, while the outgoing, or empty-handed, train keeps to the other
side ; so that on every road there is a double train of ants going in
opposite directions. When the leaves arrive at the nest they are re-
ceived by a smaller kind of worker, whose duty it is to cut up the pieces
into still smaller fragments, whereby the leaves seem to be better fitted
for the purpose to which, as we shall presently see, they are put. These
smaller workers never take any part in the out-door labor ; but they
occasionally leave the nest, apparently for the sole purpose of obtaining
air and exercise, for when they leave the nest they merely run about
doing nothing, and frequently, as in mere sport, mount some of the
semicircular pieces of leaf which the carrier-ants are taking to the
nest, and so get a ride home.

From his continued observation of these ants Bates concludes — and
his opinion has been corroborated by that both of Belt and Mtiller —
that the object of all this labor is a highly remarkable one. The leaves
when gathered do not themselves appear to be of any service to the
ants as food ; but, when cut into small fragments and stored away in
the nests, they become suited as a nidus for the growth of a minute
kind of fungus on which the ants feed. We may therefore call these
insects " gardening ants," inasmuch as all their labor is given to the
rearing of nutritious vegetables on artificially prepared soil. They are


not particular as to the material which they collect and store up for
soil, provided that it is a material on which the fungus will grow
— orange-peel, certain flowers, etc., being equally acceptable to them.
But they are very particular regai'ding the ventilation of their un-
derground storehouses, on a suitable degree of which the successful
growth of the fungus presumably depends. They therefore have
numerous holes or ventilating shafts which lead up to the surface
from the storehouses or underground gardens, and these they either
open or close according to the horticultural requirements as regards
temperature and moisture. If the leaves are either too damp or too
dry, they will not grow the fungus, and therefore in gathering the
leaves the ants are very particular that they should neither be the one
nor the other. Thus Bates obsei'ved :

If a sudden shower sliould come on, the ants do not carry the wet pieces into
the burrows, but throw them down near the entrances ; should the weather
clear up again, these pieces are picked up when nearly dried and taken inside ;
should the rain, however, continue, they get sodden down into the ground, and
are left there. On the contrary, in dry and hot weather, when the leaves would
get dried up before they could be conveyed to the nest, the ants, when in ex-
posed situations, do not go out at all during the hot hours, but bring in their
leafy burdens in the cool of the day and during the night.

Dr. Ellendorf made the experiment of interrupting the advance of
a column of these ants, with the interesting result which he thus de-
scribes in a letter to Biichner :

Thick dry grass stood on either side of their narrow road, so that they could
not pass through it witli the load on their heads. I placed a dry branch, nearly
a foot in diameter, obliquely across their path, and pressed it down so tightly on
the ground that they could not pass underneath. The first comers crawled be-
neath the branch as far as they could, and then tried to climb over, but failed
owing to the weight on their heads. Meanwhile the unloaded ants from tlio
other side came on, and when these succeeded in climbing over the bough there
was such a crush that the unladen ants had to clamber over the laden, and the
result was a terrible muddle. I now walked along the train, and found that all
the ants with their bannerets on their heads were standing still, thickly pressed
together, awaiting the word of command from the front. When I turned back
to the obstacle, I was astonished to see that the loads had been laid aside by
more than a foot's length of the column, one imitating the other. And now
work began on both sides of the branch, and in about half an hour a tunnel was
made beneath it. Each ant then took up its burden again, and the march was
resumed in the most perfect order.

The operations here described show clearly that these ants act upon
the principle of the division of labor. In this connection I may also
quote an observation of Belt, which shows this fact in perhaps even a
stronger light. He says :

Between the old burrows and the new one was a steep slope. Instead of
descending this with their burdens, they cast them down on the top of the slope,
VOL. XIX. — 52


whence they rol|ed down to the bottom, where another relay of laborers picked
them up and carried them to the new burrow. It was amusing to watch the
ants hurrying out with bundles of food, dropping them over the slope, and rush-
ing back immediately for more.

Ants of this genus are very clever at making tunnels. The Rev.
H. Clark says that in one case they have made a tunnel of enormous
length under the river Parahylia, where this is as broad as the Thames
at London — their object being to reach a storehouse which is on the
opposite bank. This statement is not to be considered so incredible as
it at first sight unquestionably appears, for Bates has seen the subter-
ranean passages of these ants extending to a distance of seventy yards.

Harvesting Axts. — The harvesting ants belong almost exclusively
to a single genus, which, however, comprises a number of species dis-
tributed in localized areas over all the four quarters of the globe.
Their distinctive habits consist in gathering nutritious seeds of
grasses during summer, and storing them in granaries for winter con-
sumption. We owe our present knowledge concerning these insects
mainly to Moggridge, who studied them in the south of Europe, Lin-
cecum and McCook, who studied them in Texas ; Colonel Sykes and
Dr. Jerdon also made some observations upon them in India. They
likewise occur in Palestine, where they were clearly known to Solomon
and other writers of antiquity, whose claim to accurate observation in
this matter has within the last few years been amply vindicated, after
having been for many years discredited, on account chiefly of the ad-
verse statements of Huber.

Moggridge found that from the nest in various directions there pro-
ceed outgoing trains, which may be thirty or more yards in length,
and each consisting of a double row of ants moving in opposite direc-
tions. Like the leaf -cutting ants, those composing the outgoing train
are empty-handed, while those composing the incoming train are laden.
But here the burdens are grass-seeds. At their terminations in the
foraging-ground, or ant-fields, the insects composing these columns
disperse by hundreds among the seed-yielding grasses. They then
ascend the stems of the grasses, and, seizing the seed or capsule in
their jaws, fix their hind-legs firmly as a pivot, round which they
turn and turn till the stalk is twisted off. The ant then descends the

patiently backing and turning upward again as often as the clumsy and dispro-
portionate burden becomes wedged between the thickly-set stalks, and joins
the line of its companions to the nest. . . . Two ants sometimes combine their
efforts, when one stations itself near the base of the peduncle, and gnaws it at
the point of greatest tension, while the other hauls upon it and twists it. ... I
have occasionally seen ants, engaged in cutting the capsules of certain plants,
drop them, and allow their companions below to carry them away; and this
corresponds with the curious account given by ^'Elian of the manner in which
the spikelets of corn are severed and thrown down "to the peojjle below."


As fui-ther evidence that these insects well understand the advan-
tages arising from the division of labor, I may quote one or two other
observations. Thus Moggridge once saw a dead grasshopper carried
into a nest of harvesting ants by the following means :

It was too large t<) pass through the door, so they tried to dismember it.
Failing in this, several ants drew the wings and legs as far back as possible,
while others gnawed through the muscles where the strain was greatest. They
succeeded at last in pulling it in.

Again, Lespis says of the harvesting ant that,

if the road from the place where they are gathering their harvest to the nest is

Online LibraryD. S. (David Samuel) MargoliouthThe Popular science monthly (Volume 19) → online text (page 102 of 110)