Arch-metals Abstracts

Laboratory analyses of nails, nail rod, and hoop iron from Thomas Jefferson's nailery at Monticello, Virginia, yield information about the methods used and the products made at American rolling and slitting mills in the early years of the l9th century. The iron, made by fining pig, is nearly free of phosphorus. It is relatively soft and ductile, having a tensile strength of 290 MN/m² and a reduction of area of 62%. Critical grain growth found in the hoop iron indicates that the metal was at a temperature of about 840°C during its last rolling pass. Rolling conditions produced an unusual pinch-and-swell structure in the slag inclusions. Bending at the edges of the nail rods indicates that the clearance between the slitter discs was about 20% of the nail rod thickness. Ferrite veining in the rod suggests that the iron passed through the slitters at a temperature between 600 and 700°C.

Keywords: NAILS, CUT NAILS, PRODUCTION, EARLY 19TH CENTURY, AMERICA, ROLLING, SLITTING, SWELL AND PINCH INCLUSIONS

Recent work suggests that Queenstock furnace at Buxted dates from at least as early as 1491. It thus predates the 1496 blast furnace at Newbridge in Hartfield, hitherto accepted as the first to be established in England.

Hydro-aeolian trompes, instead of water-wheel driven bellows, were widely used in Italian metallurgical plants up to the l9th century. They provided a blast of wet air suitable to feed the tuyeres of pyro-metallurgical plants. The air was drawn by Venturi effect into a falling stream of water, separated in a barrel after a fall of 5-10m and carried in a pipe at a pressure of less than 1m of water (lOkPa). Two examples are given of the application of the trompe, to an iron blast furnace and to a lead cupellation furnace in the Papal State at the end of the l8th century.

A second investigation into the chemical composition of the Roman Provincial (Procuratorial) coinage of Judaea, AD 6-66 Archaeometry 45 (1) 45-60

An investigation of the chemical composition of the first Roman provincial coinage of Judaea, minted in AD 6-66, was conducted. A total of 103 copper-alloy coins were analysed by ICP- AES. It was determined that different copper alloys were used for the coinage, a leaded tin-bronze and a pure tin-bronze alloy. The investigation also showed that the copper alloy was made in four different formulae with regard to the alloying elements added to copper. Trace element profiles point to the existence of a shared pool of metal for Roman coins and metalwork.

The determination of lead isotope ratios by multiple collector ICP-MS: A case study of Early Bronze Age Artefacts and their possible relation with ore deposits of the Erzgebirge. Archaeometry 45.1 61-100.

Lead isotope analyses of Early Bronze Age metal artefacts from the Aunjetitz (Unetice) culture in central Germany and Bohemia were determined in order to find out whether they could be related to ore sources of the Erzgebirge. Historical mining began only in the 12th century AD, but despite the lack of convincing field evidence it has frequently been suspected that this region was already being exploited in prehistoric times. For the determination of the lead isotope ratios, the new technique of multiple collector inductively coupled plasma mass spectrometry (MC-ICP-MS) was employed, which combines relatively easy sample preparation with highly precise and accurate measurements. The results show that there is still no evidence for prehistoric mining in the Erzgebirge, but the Rammelsberg deposit in the Harz Mountains might have supplied some of the copper. Mining of stream tin in the Erzgebirge remains a possibility, but no positive evidence can be extracted from the data.

Keywords: MULTIPLE COLLECTOR INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY, LEAD ISOTOPE RATIOS, ANCIENT METALLURGY, PROVENANCE, ERZGEBIRGE

The Chinese `Commercial revolution' of the 11 th century was accompanied by a number of important technical developments. In the iron industry, the last major advances in blast furnace design were made. Water power was widely used for the blast, and coal and coke began to take the place of charcoal for the fuel. New blast furnace structures came into use, in some cases foreshadowing early European designs and those known from the traditional Chinese iron industry of the l9th and 20th centuries. This article reviews the available evidence on the construction and operation of iron blast furnaces in the Song and Yuan periods (960-1279, 1279-1368), with special reference to the use of mineral fuel.

Keywords: BLAST FURNACE, CHINA, 10TH TO 14TH CENTURY AD, IRON, SMELTING, COKE SMELTING.

Wayman, M. and Wang H. 2003. Cast iron coins of Song dynasty China: a metallurgical study. Journal of the Historical Metallurgy 37 (1) 6-24 A selection of 37 Song dyhasty Chinese cast iron coins was subjected to metallurgical analysis. From inscriptions, these are dated between 1078 and 1215 AD, and the mint locations of 23 of the coins are known. All were found to be white cast irons, but they separated into two types, one with relatively high levels of silicon, phosphorus and sulphur and divorced eutectic microstructures, and the other with low levels of these three elements and ledeburitic microstructures. Those coins that were minted in Shaanxi were all found to be of the first type, while those minted in the HubeilAnhui region to the southeast are all of the second type. On the basis of sulphur content it is believed to be likely that iron used for the first group was smelted in coal- or coke fired blast furnaces, while the iron in the second group was smelted using charcoal. This is in general agreement with what is known of the iron industry in China during the Song period

Nine powder samples originating from the archaeometallurgical site in Göltepe, southern central Turkey, have been analysed. Bulk analyses, using X-ray fluorescence and X-ray photoelectron spectroscopy, and single particle analyses, using electron probe X-ray microanalysis, were carried out.
The analyses were focused on determining the inorganic elemental composition of the samples and the distribution of particle types in the nine powder samples. In addition, the powder samples were classified on the basis of their elemental composition using multivariate techniques. The objective of this study was to characterize the powder samples and to establish an association with archaeological data from the site.
© Archaeometry 1999

This paper investigates the question whether or not amalgam tinning was used for the plating of bronze objects in pre-Han and Han dynasty China. The relevant literary sources are reviewed and amalgam tinning is characterized experimentally with regard to its micro-structure and residual mercury content using metallography and electron microprobe analysis. Examination of a tinning sample from a Warring States dagger previously assumed to be amalgam tinned demonstrates that this was probably not the case, but that a trace of mercury found in the plating is likely to be the result of contamination.

Keywords: CHINA, PRE-HAN DYNASTY, HAN DYNASTY, SEM, X-RAY MAPPING, DAGGER, BRONZE, MERCURY, TINNING

Six Roman silver plated denarii and seven British coins (staters, quarter staters and other Celtic issues) were examined and distinct differences between the Roman and British technologies were noted. The majority of the Roman coins were produced by folding almost pure silver foil over a core of high purity copper. Whereas, the British Celtic coins appear to have been produced by either heating the blanks in contact with a silver-copper eutectic alloy until it melted or by wrapping the blank in a silver sheet and heating until the diffusion of the copper results in a eutectic type surface composition The Roman cores seem to have been more carefully prepared than the Celtic cores which seem to have been left as cast. It was thought that the one example of the iron-cored Roman coin examined would have required the use of a corrosive flux.

Lead isotope analysis has been applied to the investigation of some Roman objects found in the town of Pompeii, consisting mostly of fistulae from the Augustan water supply system. The results of the analyses have produced ratios between 18.10 and 18.66 for ²⁰⁶Pb/²⁰⁴Pb, between 15.63 and 15.72 for ²⁰⁷Pb/²⁰⁴Pb and between 38.21 and 38.98 for ²⁰⁸Pb/²⁰⁴Pb. These data point to a fairly complex origin for the lead artefacts, probably involving several successive meltings and recyclings of a rather heterogeneous lead supply. The spread of lead isotope ratios can only be reconciled with a multiplicity of end-members, at least three, but very probably more. There is one certain Sardinian ore, other indistinguishable Hercynian ores of Sardinia and/or Spain and several different Alpine Mesozoic-Tertiary mineralizations of the Mediterranean basin (Spain, Greece, Tuscany).

Keywords: Mediterranean, Italy, Pompeii, Roman, Lead Isotope analysis, fistulae plumbiferae, water pipes, lead, ores, provenance

In 1985, a number of Romano-British iron smelting furnaces had been discovered in advance of road realignment, but only two were rapidly excavated (8 & 9). In 1998 the remaining unexcavated furnace (No. 10) was excavated in advance of of the construction of a water pipeline. This furnace survived to just below blowing-hole height, 0.7m. The better preservation of the base of this furnace, together with a detailed examination elements of the superstructure, has allowed the author to make a more accurate reconstruction of the form and mode of operation of the these very large diameter furnaces. The furnace was roughly circular and 1.5m in diameter at the base, with sloping side so that the diameter narrowed to 1.2m at ground level, where at least three, but more probably 5 blowing holes. The surviving superstructure fragments suggest that the sides of the shaft of the furnace were vertical or slightly inwardly inclined, giving a possible height of 2m above blowing-hole level.
Given the size of the furnace and nature of the local ores the author suggests that the 10,000 cubic metres of slag filling the small valley down from the site was the result of about 25000 smeltings, and that the site was capable of producing up to 30 ton of bar iron per annum over the life-time of the settlement (50 years - late first to mid-second century). The author notes that the scale of production the site is comparable to that of the larger Wealden sites, and the local density of iron production sites is similar to, if not greater than, that recorded in the Weald.
CJS 1999

This paper describes the development of Henry Clifton Sorby's metallurgical researches, 1863-5, his innovative specimen preparation and reflected light microscopical techniques and use of photomicrography. The chronology of the events leading to the eventual publication of these researches in 1886-7 and the further discoveries made by Sorby at this later period are discussed.
The Catalogue lists, and includes descriptions of, the present condition of Sorby's extant glass-mounted metallurgical specimens now held in the Collections of The University of Sheffield and the South Yorkshire Industrial History Society. The specimens in the former collection were bequeathed to the University by Sorby; the latter (except one) were discovered in 1987 in the effects of Dr Thomas Andrews. It is shown that nearly half of Sorby's specimens came from one source and that each collection contains one specimen which may be identified as the first metallurgical mount ever made.
© Historical Metallurgy Society 1997

Two socketed and five shaft-hole ferrous axeheads were examined by metallography and electron probe microanalyser. Specimens from the cutting edges revealed low carbon compositions although two and possibly a third showed evidence of secondary (surface) carburization. All had been cooled naturally during their final heating cycles.
© Historical Metallurgy Society 1998

A recent suggestion that some ancient metallurgical processes might give rise to large changes (> 0.5%) in the isotopic composition of tin gave hope that it might be possible to identify ancient bronze samples which had undergone recycling and mixing processes. This paper describes a method for the analysis of the isotopic composition of tin by thermal ionization mass spectrometry and applies it to analyse a number of ancient bronzes and tin metal objects from the Bronze Age Mediterranean. No observable isotopic fractionation of tin was found above +/- O.l % in the ratio 122Sn/116Sn. Consequently, either recycling of bronze in the Late Bronze Age Mediterranean was not so common as supposed, or the isotopic composition of tin is not fractionated, by anthropogenic metallurgical processes to the extent predicted, by the Bradford group.

KEYWORDS: MEDITERRANEAN, BRONZE AGE, MASS SPECTROMETRY, INGOT, BRONZE, TIN, ISOTOPIC COMPOSITION, ISOTOPIC FRACTIONATION, RE-MELTING, RECYCLING
© Archaeometry 1997

Among 22 links recovered in Florida from Hemando de Soto's expedition, four were of tin bronze and the remainder of iron. Most of the iron links were completely mineralized but sectioning revealed remnant areas of sound metal in eight links. The microstructures indicated that the links were fabricated from drawn wire by riveting. There was no conclusive evidence that high phosphorus iron had been selected for the wire.
© Historical Metallurgy Society

The regional and local geology underlies the availability and type of natural resources, be it ore, woodland or water, and was the fundamental influence on the locations chosen for iron making. Possible sources of iron ore available to early bloomery iron workers in Scotland have been established from the recorded sources of iron ore. Moreover, using modem knowledge of iron geochemistry as well as the local and regional geology, further potential sources of iron may be predicted. The question of the original ore used at a bloomery site can be tackled by looking for the remains of ore processing/crushing, using techniques such as ore petrography. In spite of much geological evidence for potential iron ores other than bog ore, no positive evidence for their use was found at the bloomery sites investigated. Iron-rich manganiferous slags with minor silica suggest that bog iron ore was used

Utilising a collection of family letters, the article looks at the role of English immigrants in the emergence of the American special steel industry, c1850-1914. Specifically, it chronicles the careers of the Illingworth brothers - particularly Benjamin and John - and their role in the foundation of the New Jersey steel trade. The activities of the Illingworths at pioneering firms, such as the Jersey City Steel Works and Atha & Illingworth, demonstrate the dependence of the US special steel industry on English expertise. The remarkable upward social and economic mobility of the Illingworths is also highlighted.

This annual report in English contains abstracts of 37 site reports, two research reports, and a list of 12 papers published or accepted for publication in 1997. The site reports include studies to determine the temperatures to which fire-cracked-rocks have subjected, identification studies of stone artefacts and ores, together with analytical studied of iron and other metal-working slags, slag-tempered pottery, and of trade-bars of iron and tin the latter was thought possibly to be an import from Cornwall on the basis of the high iron content. The research reports dealt with petrographic geo-thermometry, one study was on the use of fission tracks as a method of determining if a rock has been heated, the other was a study of vitrified material from Hunsbury Hillfort, England, and an experimental comparative smelt of the local iron-stone.
Most of the full reports referred to in this annual report were in Swedish..

Glow discharge optical emission spectrometry (GDOES) has been used for obtaining calibration curves for copper, tin, lead, silver, antimony, arsenic, zinc and iron from standards including copper-based alloys (Cu 61.33-99.95%) and from bronze Punic coins. The GDOES results were calibrated using atomic absorption spectroscopy with inductively coupled plasma atomization (ICPAAS) to analyse the standards and coins. For all these materials, the results show that via GDOES it is possible to obtain reliable and reproducible calibration curves for copper, tin, lead, zinc and iron with a linear behaviour as a function of the content. The quantitative GDOES and ICPAAS data for the coins have been also compared with those obtained via X-ray fluorescence (XRF) and it is shown that GDOES, ICPAAS and XRF agree well with one another considering that the bronze coins are inhomogeneous to some degree. As an example of GDOES analytical features, a depth concentration profile through a thin bronze patina is shown and briefly discussed.

KEYWORDS: MEDITERRANEAN, PUNIC, ATOMIC ABSORPTION SPECTROSCOPY, GLOW DISCHARGE OPTICAL EMISSION SPECTROMETRY, INDUCTIVELY COUPLED PLASMA ATOMIZATION, X-RAY FLUORESCENCE, COINS, BRONZE
© Archaeometry 1997

Detection of near-surface silver enrichment on Roman imperial silver coins by X-ray spectral analysis.

Archaeometry 41(2) 311-320

Keywords: ROMAN EMPIRE, FIRST TO THIRD CENTURY, SEM-EDS, WDS-XRF, X-RAY SPECTROMETRY, COINS, SILVER, SURFACE ENRICHMENT

Samuel Parkes' notable early contribution (1826) to the knowledge of the composition of base metal alloys of the Roman Imperial coinage has been overlooked in all the relevant works of reference. His work surpassed in extent and equalled in reliability subsequent investigations of the next 50 or more years. The present account and evaluation of Parkes' efforts is intended to restore his achievement to its rightful place in the history of the chemical analysis of archaeological and numismatic objects.
© Historical Metallurgy Society 1997

Twenty -four cast copper crotals (commonly, called bells), one ,'spilled bell', one tinkler bell and a number of minerals from locations throughout the Greater Southwest were analysed for their elemental composition by a PIXE nuclear microprobe at Los Alamos National Laboratory, New Mexico, USA. Sixteen bells contained minor and trace amounts of silver, antimony, arsenic, lead, and in some cases tin, strontium, and selenium. Nine bells contained little or no detectable amounts of these elements. This suggests that several workshops throughout the Greater Southwest and Mexico might have manufactured these bells.

KEYWORDS: USA, GREATER SOUTHWEST, MEXICO, PRE-COLUMBIAN, PARTICLE INDUCED X-RAY EMISSION MICROPROBE ANALYSIS, BELL, CROTAL, COPPER, COMPOSITION, WORKSHOPS, TRADE
© Archaeometry 1998

J. L. Mauk and R. G. V. Hancock 1998

This paper describes aspects of the metal working technology employed during the 17th-19th centuries AD at the site of Nqoma, excavated by James Denbow and Edwin Wilmsen, in NW Botswana. A detailed metallographic analysis of eleven artefacts showed that the indigenous Late Iron Age fabrication technology did not differ significantly from its Early Iron Age counterpart. Forging, and possibly smelting, of iron took place at the site. Inhomogeneous bloomery iron was used in conjunction with scrap metal to forge items of jewellery and small tools in an oxidising hearth. The forging technique was generally poor, with surface oxide scale incorporated in welds, and with no control over subsequent heat treatment. Copper was worked in the same way, leaving the metal in its annealed state.
© Historical Metallurgy Society

The paper includes the write up of work recently out on the crucible slag from a complete cup-shaped handled crucible of circular plan and conical profile found during the 1939/1940 excavation of an Iron Age hillfort on the borders of England and Wales. The form and method of heating of the crucible is compared with crucibles from Llwyn Bryn-dinas and later Iron Age crucibles. It is argued that the cup-form crucibles, which were heated from the bottom and sides, are from the early Iron Age. Whereas, the crucibles of triangular form, which were heated from the top, are from the latter part of the Iron Age, Analysis of the contents revealed crucible slag with high zinc contents, similar to the pattern found at Llwyn Bryn-dinas. It is suggested that Llanymynech might have been the source of the copper. A metal prill examined proved to have over 40% tin, thus, raising the possibility that the crucible might have been use for bronze making, However, as other bronze melting crucibles have yielded high tin metal prills, the case for bronze-making remains un-proven.

M. Ponting and L Segal 1998

A selection of Roman military fittings and associated copper-alloy artefacts was analysed by inductively coupled plasma-atomic emission spectroscopy. The method used was a variant on those previously published and gives very good precision and accuracy. The Roman metalwork analysed conforms extremely well to similar artefacts analysed from contemporaneous European sites and suggests, despite the strongly 'local' nature of the Judaean legions, a considerable unifiurmity ofalbying practice within the Roman army during the first century AD.

This book is a catalogue of 2099 XRF (EDS) analyses of Iberian Chalcolithic and Early Bronze Age copper alloy objects, together with some ores and ceramics associated with copper working.

Lead isotope and trace element analysis in the study of over one hundred South Indian metal icons. Technical investigations were made on 130 South Indian statuary images and a few miscellaneous artefacts mostly sampled from the Government Museum, Madras, India, and from the Victoria and Albert Museum and the British Museum, UK. Lead isotope investigations were attempted on 60 of these, and compositional analysis for 18 elements on 115, using inductively coupled plasma optical emission spectroscopy; thus, for 40 objects both lead isotope and trace element analysis was done.

From the isotopic and elemental framework, insights are obtained into some art-historical problems of images and artefacts of the Pre-Pallava, Pallava, Chola (i.e., Vijayalaya Chola), Later Chola (i.e., Chalukya-Chola and Later Pandya), Vijayanagara (and Early Nayaka) and Later Nayaka (and Maratha) dynasties, spanning the Early Christian era to the nineteenth century, along with a few other regional styles. Inferences are also made regarding provenance of the lead and the early use of zinc and brass in the early historic period (c. fourth century BC-fourth century AD).

Binary high-tin bronze alloys have been recorded in SE Asian antiquity, and it had been reasonable to regard known Indian examples as imports from tin-rich SE Asia due to the scarcity of tin in India. However, this paper puts forth new evidence of ancient and surviving high-tin bronze working, in the Indian subcontinent. It challenges the above assumption and indicates that the indigenous development of high-tin bronze working, and exploitation of the sparse tin deposits in ancient India, cannot be ruled out. Surviving traditions from Kerala in S India are documented of the manufacture of 'vessels and instruments of wrought and quenched high-tin bronze, and mirrors of cast high-tin bronze. New metallurgical evidence is presented for the continuous use of artefacts of high-tin bronze in the subcontinent from the Ist millennium BC to the present day, particularly in South India, which is corroborated by literary and iconographic evidence from the historical period.
© Historical Metallurgy Society

Nearly 200 new lead isotope analyses of sulphidic and oxidized ores from 26 copper mines on Cyprus show that the mines from different geological regions group in five distinctive isotopic groups, each with a substructure related to the geological history of the ore formation. Comparison of lead isotope compositions of Bronze Age artefacts with these data can in many cases reveal the actual mines from which the copper for particular artefacts was obtained. The particular case of the provenance of the copper for 78 Late Bronze Age copper 'oxhide ingots' found in Cyprus, Crete, Greece, Sardinia, Turkey and Bulgaria is discussed. The data show that all oxhide ingots so far- analysed, dating to the fourteenth century BC and later, were made of copper consistent isotopically with only one mining region in the geographical north of Cyprus, and especially the Apliki mine. The study provides further evidence which supports the validity of the conventional approach to the use of lead isotope analysis for provenancing metals; this evidence is antithetical to recent suggestions of a model for the production of copper oxhide ingots which involved widespread mixing of copper from a number of ore sources throughout the Mediterranean.

KEYWORDS: CYPRUS, BRONZE AGE, LEAD ISOTOPE ANALYSIS, COPPER OXHIDE INGOTS, ORE DEPOSITS, COPPER, METALLOGENESIS, PROVENANCE
© Archaeometry 1997

These two volumes form a most beautifully produced catalogue of all the Bronze Age metalwork in Slovenia. A large part of the second volume is formed by a discussion of the analysis of almost 1000 pieces of the metalworks including a variety of ingots of bizarre compositions. The whole work is a good example of how to publish and discuss Bronze Age metalwork and metallurgy.
Peter Northover

Geophysical surveys are a standard method of site assessment. However very few are used specifically to evaluate structures associated with metallurgical activity. Routine geophysical surveys frequently encounter ironworking activity but this data is usually ignored as it tends to be excessively 'noisy' and difficult to interpret. A combination of geophysical surveying techniques were applied to three iron smelting sites in North Yorkshire to invesfigate the effectiveness of geophysics in identifying iron-working activity.

The paper is an eyewitness report of present day copper smelting using a small blast furnace.
© Historical Metallurgy Society

Wanhill,R. J. H., Steijaart, J. P. H. M., Leenheer, R. and Koens, J. E W 1998.

Damage assessment and preservation of an Egyptian silver vase (300-200 BC)

Archaeometry 40(1) 123-137

An Egyptian metalvase from the Ptolemaic period was investigated metallurgically and fractographically. The metal is nearly pure silver. Despite its high purity (in archaeological terms) it is severely enbrittled and cracked, mainly along grain boundaries. Factors contributing to this damage are work-hardening and residual microstructural deformation (slipping and twinning), corrosion along slip lines and twin boundaries, corrosion in bands that are the remains of coring, large equiaxed grains, externally applied forces and internal residual stresses. The metal is now friable. This must be taken into account during any further restoration of the vase: a procedure is suggested.

Some experiments on quenching and tempering were carried out on a sample of modern ultra-pure steel and two specimens of 16th century armour, to observe changes in hardness with time at low tempering temperatures. The hardness of the specimens of armour fell more rapidly than might have been expected by comparison with modern steels. This has suggested a reason why gilding was found to be a difficult process to combine with hardening by armourers.
© Historical Metallurgy Society

Among the Nigerian cast copper-alloy artefacts, the chronology of the Benin memorial heads has been the most fully worked out. Therefore, a study focused upon their elemental compositions is particularly likely to be interpretable in terms of development of the alloys used in their making. The elemental analyses, both published and unpublished, of 66 Benin heads, supplemented with seven analyses of some artefacts excavated from a well-dated, very early Benin site, have been collected, analysed statistically and compared to the elemental analyses of 11 heads and figures from Udo. All but a very few of the Benin heads and artefacts separate into five compositional groups, indicating a chronological sequence of different alloying traditions. All but one of the Udo objects fall into a distinctly separate compositional group, together with two Medicine heads. The compositional groups correlate remarkably well with the stylistic types proposed by Dark.

Keywords: NIGERIA, BENIN CITY, UDO, MEDIEVAL, MEMORIAL HEADS, BRASS, COPPER ALLOY, BRONZE, COMPOSITION, DATING, XRF, AAS, COMPOSITION, DATING OES, PIXE, MULITVARIATE STATISTICAL ANALYSIS

A selection of fragments of steel files excavated from dated western Canadian fur trade sites has been examined metallographically to assess their value as chronological indicators. It was possible in some, but not all, cases to identify the steelmaking process, distinguishing between cementation steel and crucible steel. In other file fragments manganese was detected in the steel both as manganese sulphide inclusions and in solution in the steel matrix. The identification of crucible steel provides a terminus post quem of 1740 for the fragment, and the presence of manganese a terminus post quem of about 1840. The site occupation dates were consistent with the dates deduced from the steelmaking technologies.