Cast Iron

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. . . growth of human greed. But leaving out of consideration the references to moral explanations that result from the tendency of some Greek philosophers to ascribe profound ethical value to Spartans institutions, ancient sources are correct when they connect the use of iron money with the isolation of Sparta from the general stream of Greek economy. The archeological data suggest that the Spartan economic decline began around 600 B.C. But the problem is that of deciding whether the use of iron money is the cause or the effect of the economic isolation of Sparta.

In my study of Greek chronology I shall show that historians used the date of the imaginary Pheidon of Argos to establish that of Lykourgos: they made Lykourgos, who would have made compulsory the use of a currency of iron oboloi in Sparta, a contemporary of Pheidon, who would have abolished this currency in the rest of the Peloponnese. The date of Lykourgos and of the Spartan constitution was moved from one century to another according to the shifts in the position of Pheidon in the several chronological schemes. This link indicates that the peculiar economic position of Sparta is related to the setting up at the Heraion of standards that were later associated with the name of Pheidon.

I would suggest the following explanation of the events. Up to the time the standards were set up at the Heraion (roughly about 670 BC), the currency of the Peloponnese was utensil-money consisting of oboloi. The objects of the Heraion introduced a new concept of currency, metals measured by weight, whether they be iron or silver, and established a relation of value between the utensil-money of oboloi and the new currency. When an equivalence of value is established between two currencies, Gresham’s law becomes operative; hence, I would suspect that there was some factor by which the iron currency turned out to be the “bad money” in Sparta, so that silver money was driven out. This may have caused, or contributed to, the economic isolation of Sparta.

6. In my opinion the history of the Peloponnese, and of Mykenai and Sparta in particular, cannot be properly reconstructed without collecting all possible data about mining and metallurgy in the area. After submitting my doctoral dissertation I tried to obtain institutional support for a metallurgic testing of the iron found at the Heraion and at Sparta. The basis of my request was a statement of Ploutarchos (Lysandros, XVII), drawn from older sources, that the Spartan iron money as it was drawn out of the fire was dipped in vinegar, so that it would become unfit for forging, brittle and incapable of taking good edge.

A metal which is quenched by dipping into vinegar certainly is not wrought iron; it must be cast iron or steel. The quenching in vinegar, instead of water, is mentioned in the Pirotechnia of Vannoccio Biringucci (1480-1539 A.D.); ancient metallurgists ascribed great importance to the nature of the quenching medium, and many of their notions, such as the preference for the water of particular streams, may have been superstitions, but vinegar may actually be a better wetting agent than water, as would be a saline solution. I concluded that the metal described by Ploutarchos was cast iron. A number of ancient sources mention the preservation of cast iron in temples as particularly valuable or marvelous. According to Pausanias (III, 12, 10) the edifice called Skias in Sparta was built by Theodoros of Samos (a sort of Leonardo da Vinci of the Greeks—architect, sculptor, inventor), “who first found the way to pour iron and to mold statues with it.”

In spite of such clear statements of ancient authors, the occurrence of cast iron in antiquity has been denied a priori with the argument that ancients could not obtain the temperature of about 1500° Celsius necessary for liquefying iron. For the smelting of the ore a temperature of 500° may be sufficient; at a temperature between 800° and 900° wrought iron becomes sufficiently soft to be worked with the hammer. I may quote as typical the opinion of the specialist of ancient Egyptian technology, Lucas, to the effect that only in the fourteenth century of our era the construction of furnaces become advanced enough to obtain the temperature necessary for the melting of iron. It is true that the furnaces used in Europe up to this time and those currently used in classical antiquity were not intended to generate a high temperature; but from the metallurgic treatises of Renaissance it can be gathered that metallurgists were on the alert against letting the temperature of a furnace rise too high lest cast iron be produced. Until steel began to be produced by reducing the carbon content of cast iron, was considered a useless from of iron, “sick iron” in English terminology.

Even when iron is smelted in furnaces of low temperature that are intended for the production of wrought iron, parts of the bloom that forms in these furnaces is composed of cast iron and even of steel. Metallurgists used to break up the bloom and separate the pieces that are wrought iron; the pieces of cast iron were considered rejects. It is for this reason that around 1500 AD there was introduced in Europe a method for utilizing more fully the products of the furnace; the pieces of cast iron were melted forming what Biringucci calls latte di ferro, “milk of iron” and into this there were dropped pieces of wrought iron. Since cast iron has a high content of carbon, whereas wrought iron contains less than 0.2 per cent of carbon, by making an average there was obtained steel. Low-carbon steel has a carbon content between 0.2 and 0.8; high-carbon steel with a content between 0.8 and 2.0 is much harder, but it must be cast into forms and cannot be easily welded. The reason for the spread of the use of steel in modern Europe was in part that of utilizing what were originally the wasted parts of the bloom.

A fundamental contribution to the solution of the problem of Spartan metallurgy was made when Lyle B. Borst, Chairman of the Department of Physics at New York University College announced (The New York Times, January 31, 1961) that he had taken some samples from specimens of Spartan iron money and found then to be made of low-carbon steel, with a carbon content of between 0.2 and 0.8 percent. A few days later, in answer to a letter of mine, he kindly informed me that he had not had an opportunity of obtaining a sample of the oboloi of the Heraion.

It could be said that the finding of Borst is not as sensational as the press report made it to be, since the existence of Spartan steel is mentioned in specialized literature. But, for the first time, scholars are provided with a solid objective datum in a field where there is good deal of confused thinking and there are too many unjustified assumptions.

In order to obtain a precise bearing I may quote the opinion expressed in 1956 at the Colloque International: Le Fer à travers les ages a specialist of Celtic metallurgy, Albert France-Lanoud:

It seems that steel become known in Greece at an extremely early date, but this not established as certain. But it is a fact that the Celts of the Noricum around 500 BC discovered the method to avoid a complete decarburization of the bloom and to produce an excellent malleable steel. It should be called natural steel. It is this discovery that gave a reputation to the iron works of Noricum; it must have been the secret of several groups of ancient ironsmiths. But in Gaul steel appears later, in the second century BC Noricum roughly corresponded to the western part of contemporary Austria and the neighboring part of Bavaria.

The objective fact ascertained by Borst acquires transcendental significance for the study of Greek history, because he has brilliantly liked it with a passage of Herodotos (I. 67, 68) that provides information about the relation between Spartan metallurgy and Spartan ascendancy in the Peloponnese. Herodotos reports that at a time that preceded the age of king Kroisos of Lydia (middle of sixth century B. C.) the Spartans had been repeatedly defeated in their efforts to establish their ascendancy over the people of neighboring Arkadia. When they asked the oracle of Delphoi for advice, they would have received the following answer:

In a level part of Arkadia there is a place called Tegea: there two winds blow under forceful compulsion, there is hitting and counterhitting and misery lies upon misery. There the fertile earth holds the son of Agamemnon; by getting him you shall become the master of Tegea.

The riddle was solved when a Spartan emissary by the name of Lichas visited the shop of an blacksmith at Tegea. He recognized that the smithery was the place indicated by the oracle: he saw two bellows opposite to each other blowing toward the fire (such opposite bellows appear in Egyptian portrayals of ironworks), he saw an anvil upon which there was falling a hammer and he saw the beaten metal, which is misery upon misery, “since iron was invented for the evil of man.” The blacksmith told Lichas that the reason why the latter was finding the particular working of the iron an object of wonder was that in digging a well in his shop the smith had found an urn of unusual size, seven cubits long, containing the bones of a man of the same size. The Spartan understood that these were the bones of Orestes mentioned by the oracle. By paying the blacksmith, the bones were brought to Sparta: as a result Sparta became much stronger in war and was able to subject a great part of the Peloponnese.

It is indeed a commentary on the state of Greek studies that a professor of physics who does not know Greek was one who realized the vital importance of this statement of Herodotos for the understanding of Spartan history. According to Herodotos, the supremacy of the Spartans in the Peloponnese resulted from their acquiring a metallurgical secret formerly kept the people of Tegea.

In Borst’s view this passage of Herodotos indicates that Spartan military superiority was based on the knowledge of process for the production of steel. I do not know how Borst explains the technical details of the process involving a box and the bones of Orestes, but I believe that the explanation is provided by a famous memoir of the scientist Réamur on the making of steel, published in 1722 AD He tells how he searched for a method to improve the qualities of cast iron, which “is absolutely incapable of being worked with the hammer and is at the same time so hard.” He found a method of transforming it into steel by heating it up packed together with calcinated and pulverized bones. Since cast iron was considered worthless iron up to rather recent times, a “sick iron,” it is possible to understand why the combination of bones with cast iron was called a piling up of “misery upon misery.” I suspect that Herodotos missed the explanation of this element of the riddle.

The method used by the Spartans must have been similar to that used by the Chinese. It seems that iron began to be produced in China in the fifth century B. C.; the method used by the Chinese was that of producing cast iron and then reducing it to steel. Pliny, in the first century of our era, mentions China and Parthia as the important producers of steel. Some scholars, being wary of accepting that steel was produced at very early times, have tried to choose the to lowest possible date for the production of Chinese steel. But Chinese texts of the first century AD mention the production of steel by melting wrought iron in a bath of cast iron. It has been argued that the other process, that of reducing the carbon content of cast iron, was discovered later, because this has been the consequence of the developments in Europe; but the Spartan evidence suggests that decarburation may have been the earlier process. The process of co-fusion of cast iron with wrought iron requires a temperature, such that the cast iron becomes a liquid in which the pieces of wrought iron melt.

Several scholars have been confused by the fact that steel is a highly desirable metal for us. But the ancients were looking for a metal that was highly malleable and considered anything that was not malleable an inferior product. For instance, it has been noticed that in the Homeric poems iron is mentioned, but the weapons of the heroes are described as of bronze; on the basis of this fact it has been argued that weapons of iron were current in the age of Homer, but the poet deliberately chose to describe the customs of an age that preceded him. In my doctoral dissertation I argued that Homer was not an antiquarian: by the metallurgy of his time armor and swords could not be made of iron, but objects such as a ploughshares, hoes and mattocks could. By further investigating the problem I found that iron armor was seldom produced before the beginning of our era. Up to this time, the best possible use of iron could be that of making small cutting blades, points of spears and short swords. A highly capable blacksmith could succeed in producing a full-sized sword of steel, but this must indeed have been a rare piece that was not cheaper than a sword of bronze.

Henry B. Noss submitted in 1959 a doctoral dissertation on ancient copper metallurgy, in which there are incidental remarks on iron metallurgy that agree with my general view. He observes that “the heat treatment of iron was very difficult and complicated, that of copper comparatively simple”; he properly calls to attention the ancient texts that describe iron as an evil metal. Homer calls iron polykmeitos, “wrought with great toil.”

To Noss there occurred the wise idea of examining the first occurrence in Greek literature of words composed with sidero-; as a result he established the following timetable: in the first century A. D. flesh-hooks and crowbars; in the, second century, anchors and files; in the third plaiting and borers; in the fourth, tunics, fetters and horseshoes; in the fifth, breastplates; in the tenth, wheels. Of course, the first occurrence of the terms is not an absolute evidence when certain objects began to be commonly made of iron, but the timetable taken as a whole indicates that iron metallurgy was still growing from an infant state at the beginning of our era.

The written and material evidence indicates that here and there in the ancient world there were produced steel blades and even steel swords; these steel objects may even have preceded the general use of iron. The Egyptian iron objects that occur in solitary fashion in the two millennia preceding the Saite Dynasty should be examined to determine how often they are made of steel.

Since the distinction between Bronze Age and Iron Age is the the most fundamental classification scheme in ancient archeology, it is followed by people who have given little thought to metallurgy, or none at all. As a result there have been formed myths in the history of metallurgy that wen be dispelled only with a most detailed technical study of the evidence. A first effort in the right direction has been made by Noss, who has shown that there is no such thing as a unified copper metallurgy: a number of separate techniques must be distinguished, some more primitive and some highly advanced, that appeared in different areas and at different times, some being lost in the course of time. He has shown that the manufacture and the general use of tools characteristic of the so-called Stone Age continued through the Bronze Age in some areas. On my part, I would stress the point that iron appears to have been known about as early as copper, but was considered an inferior metal. The only specific advantage of iron was that of providing a better cutting edge; for the manufacture of cutting instruments iron was more desirable than copper even if it was more expensive. It would seem that cutting blades of iron were produced during the Bronze Age; hence, the first iron to be produced must have been steel. The Greek name for “steel” is stomoma; since stoma means “mouth, front part, point of a weapon,” the name of steel may refer to the fact that originally it was used just for the cutting edge or the point of instruments, being even mounted on a bronze support. When historians speak of Iron Age they actually refer to the fact that at a point in history it became possible to produce some objects more cheaply with wrought iron than with bronze; the number of the objects that could be so produced kept increasing in the course of the Greek and Roman period. The Greeks continued to use the term chalkeos for “smith,” a term that properly applies only to the “coppersmith,” because only copper or bronze was the metal truly fit for all the operations of smithing.

Noss suggests that there was a resistance to adopt iron, because the metallurgy of copper had achieved such a high level of perfection that it would not be abandoned in favor of a more primitive technique; but he does not explain why the technique used for iron should have remained in a primitive state. I believe that the proper exploitation of iron required a technique even more advanced than the highest copper technique. I am inclined to think that a sociological factor must be taken into account: up to the first century B. C. there had not been established any method for the advanced training of slaves. Since metallurgy was usually entrusted to slaves, the highly developed skills in iron metallurgy that were developed here and there could not be easily transmitted to future generations. Apparently the skill needed for handling copper was at the level of the usual training of slaves. It could be that in Lakonia where there was a social class, the perioikoi, with a status intermediary between that of full citizens and that of slaves, the social conditions were more favorable to the formation of a group that could acquire the secrets of steel metallurgy and transmit them to future generations. Metallurgists have been secretive up to recent times; but the formation of so-called trade secrets was inevitable as long as there had not been developed a language that would allow to explain the operations properly. The difficulty that we meet in interpreting ancient authors, such as Aristotle, when they deal with metallurgy, indicates that such a language did not exist. The history of alchemy indicates that the lack of a proper language caused the efforts to transmit chemical knowledge to founder in a sea of superstitious constructions. The description of iron metallurgy is particularly difficult. In the case of bronze and brass the main problem is that of obtaining the right proportion of metals; but in the case of iron the metal comes out of the smelting furnace with a variable content of carbon that radically affects its characteristics. Furthermore, any process of heating and hammering alters the characteristics of iron, which depend on the size, the distribution and the orientation of the composing crystals.

It would seem that the effort to develop a metallurgy of wrought iron caused the loss of the technique for the production of cast iron and steel in Greece and Rome. When I wrote my doctoral dissertation I suggested that the iron objects mentioned by Homer were of cast iron; now I would conclude that they were of cast iron and of steel, possibly high carbon steel. In describing the blinding of Polyphemos, the poet compares it vividly with the quenching of iron in water. Both cast iron and steel become harder and more brittle by being quenched in water, but only steel can have a sharp edge. Odysseos and his ten companions plunge into the eye of Polyphemos the charred point of a pole, and the effect is compared with the sizzling of water when an iron axe or an adze is plunged into it by a smith to make it hard. A number of editors expunge this passage (IX. 391-394) as a late addition, but the evidence seems to suggest that the making of steel was better known in preclassical than in classical times. It has been argued that the text is late, since it contains the phrase megala iaconta, “with great shout” which ignores the digamma at the beginning of the second term. But the usual epic form is mega Fiaconta, so that the text must have originally taken the digamma into account; when the digamma was no longer pronounced, mega was changed into megala so that the verse may sound correct.

7. Considering again the statement of Ploutarchos about the Spartan iron money, it seems that he telescoped the information. He mentioned the production of cast iron and the process of quenching the metal, but he did not mention the intermediary process of decarburizing the metal. Ploutarchos may have shortened or misunderstood the information provided by his source: the metal that was unfit for forging, brittle, and incapable of taking a good edge when it came out of the smelting process, was subjected to the process mentioned by Herodotos and then heated again to be quenched in vinegar which would make it even more brittle and more unfit for forging, but capable of taking a good edge. Ploutarchos instead states that it was quenched in vinegar so that it would become unfit for forging, brittle, and incapable of taking a good edge.

The evidence gathered by Borst indicates that the Spartans acquired from the people of Tegea the technique of decarburizing cast iron or high carbon steel. It is significant that Tegea is in the southeastern part of Arcadia on the road from Sparta to Argolis. In the period of the fifth century B. C. in which Argos destroyed the neighboring cities and took control of the Heraion and of Nauplia, Tegea revolted against Sparta and became an ally of Argos. Since the process of decarburation is connected with the name of Orestes, son of Agamemnon, king of Mykenai, it maybe that the process originated in the area of the Heraion.

I have listed the sources that state that iron was invented in Euboia, that is, at the Heraion and that mention Euboia as a famous metallurgic center. Here, I must call attention to a line of Aischylos that mention an Euboic sword called autotektonos. It may be a sword of steel. The term autotektonos maybe compared with the term autokhoónos that occurs in Homer. In the funeral games for Patroklos, Achilles offers a great ball of iron as a prize to the hero that will throw it the greatest distance; the narrative indicates that to lift the object at all is already a feat. Achilles states that the object would be of use to the holder of a large estate, who will be able to provide all the iron needed by his farmers and shepherds for five years. The object is called solon autokhoónon literally “self-poured lump.” Some interpreters have understood that it is a matter of meteoric iron which is “self-smelted.” But the Hellenistic scholar Aristarchos never doubted that melted metal is mentioned, since he observed that it must be a matter of copper in spite of the words of Homer, because iron cannot be melted. Paul Mazon translates: un bloc de fer brut; this translation is rather indefinite, but at least does not contain an error. The glosses to the passage explain that autokhoónos means as the metal comes from the smelting. It would seem, therefore, that the prize offered by Achilles is a bloom of iron as it is formed in the furnace. In substance both autokhoónos and autotektonos may have referred to metal in its usual first state of production. The usual practice of ancient times, followed up to modern times, was to produce a bloom in a low-temperature furnace and then break it up, separating the pieces of wrought iron from those of steel and cast iron. The practice of classical times, followed up to the Renaissance, was to discard all the pieces that were not wrought iron. It would seem that in some areas of Greece at some time the pieces of steel were utilized. A bloom found in the ruins of the Roman Corstopitum near Corbridge, on the Tyne was analyzed and found to be composed of parts that are steel. It may be suspected that the ancient metallurgy was always based on the low-temperature furnace producing a bloom; but at first the furnace was operated so as to produce as much as possible cast iron and steel. It may be conjectured that the first parts of the bloom to be utilized were these of steel; then development took two opposite directions, that of utilizing wrought iron and that of converting cast iron into steel.

8. In spite of the fact that the oboloi tested by Borst are of steel and possibly all oboloi were of steel, I still am inclined to believe that Spartan iron money was made of cast iron in classical times. In the Temple of Artemis Orthia the main holiness of Sparta, there have been found iron bars that have roughly the shape of oboloi, but are short and thick, and cannot have been used as roasting spits. In general when a utensil is used as currency its shape and metal tends to degenerate and acquires a merely symbolic character. Therefore, I suggest that the Spartans may have used cast for making the oboloi used as currency.

The indications that the iron money of the Spartans come to be made of cast iron are the following. The pseudo-Platonic dialogue Eryxias (400 B) states that Spartan money is made of useless iron, in order to prove that money may have a purely conventional value. This statement can hardly refer to oboloi of steel. The true oboloi found at Sparta, from which Borst took some samples, may have been pieces preserved in temples like the oboloi found at the Heraion. The Spartan iron money used in classical times was called pelanos. A number of inscriptions indicate that pelanos, like obolos, passed its name to the monetary unit obol, particularly to the obol paid as fee for the consultation of an oracle. The fee continued to be called pelanos even when it became more than an obol. Linguists explain the term by referring to the root of the Latin planus and of the English flat (German platt), and it has been suggested that originally a flat cake was offered to the oracle. But I would rather consider a derivation from the root of plassó, “to mold a soft substance” from which there is derived plasma and our term plastic. Suidas explained that pelanos is a kind of mushy pastry, the froth around the mouth, the gum of a tree and the obol paid for the consultation of an oracle. A gloss to Nikandros (Alexipharm, 488) remarks that pelanos, means “obol” and also pemma, “pastry”; it explains this last word by epsema, “boiled-down substance.” The smelting of ore is called epsesis. The term pelanos, therefore, seems to suggest that Spartan money was made of melted metal.

It is possible that in the case of oboloi used as currency, the Spartans come to skip the process of decarburation with the urn and the bones of Orestes. The oboloi of cast iron had to be made short and thick lest they break. In his Dictionary Pollux refers to the quenching in vinegar of Spartan oboloi, but in terms different from those used by Ploutarchos: “They quench the point of the obolos in vinegar so that it becomes incapable of being cut.” This statement is perfectly sensible from a metallurgical point of view: the point of the obol is quenched so as to make the steel harder; but the shaft is not quenched, because the quenching would make it harder but also brittle.

Gathering all the data, I would conclude that the Spartans abandoned the process of producing wrought iron and adopted from the people of Tegea a process which consisted in producing cast iron and then decarburizing it, the process used by the Chinese. This process was excellent and most desirable for the production of oboloi used as utensils, but too expensive for the oboloi used as currency. Svoronos may be right in assuming that the bar of the Heraion was of wrought iron. If the bar was of wrought iron, the relation of value 1:400 established by this bar between silver and iron applied to wrought iron. When the Spartans began to produce oboloi of steel, this relation was too unfavorable to iron in the case of steel objects. They may have exported oboloi of steel to be used as utensils; but as money they used oboloi of cast iron for which the rate of the Heraion was too favorable to the iron. Since Ploutarchos may be interpreted as saying that the proper rate for oboloi of cast iron was 1:1200, the Spartan money was considered worthless outside Sparta. However, the entire history of Sparta, and not only her monetary history, will continue to hover in the realm of legends and be a fit subject for rhetorical exercises of Spartan virtues and on auri sacra fames, as long that the metallurgic data potentially available are not gathered.