Archaeometallurgy -- an island?

REHREN, THILO

VINCENT C. PIGOTT (ed.). The archaeometallurgy of the Asian Old World (University Museum Monograph 89, University Museum Symposium Series VII, MASCA Research Papers in Science & Archaeology 16). iv+207 pages, 37 figures, 29 tables. 1999. Philadelphia (PA): University of Pennsylvania Museum; ISSN 1048-5325 hardback.

ANDREW RAMAGE & PAUL CRADDOCK (ed.). King Croesus' gold: excavations at Sardis and the history of gold refining. 272 pages, 230 figures, 35 colour illustrations. 2000. London: British Museum; 0-7141-0888-X hardback 45 [pounds sterling].

GILLIAN JULEFF. Early iron and steel in Sri Lanka: a study of the Samanalawewa area (Kommission fur allgemeine und vergleichende Archaologie, Materialien zur allgemeinen und vergleichenden Archaologie 34). viii+422 pages, 160 figures, tables. 1998. Mainz: Philipp von Zabern; 3-8053-2512-6 hardback DM78 & e39.88.

SANDY GERRARD. The early British tin industry. 160 pages, 74 figures, 29 colour photographs. 2000. Stroud & Charleston (SC): Tempus; 0-7524-1452-6 paperback 14.99 [pounds sterling] & US$24.99.

With some 15 years of research experience in archaeometallurgy, I find it increasingly difficult to define what archaeometallurgy separates from archaeology proper. This fuzzy definition issue of archaeometallurgy became again very apparent to me when I found myself with the task of reviewing a number of rather different books, all of which sailed under the same name `archaeometallurgy', at least (I presume) in the perception of the Review Editor of this journal.

Let's open the bag and have a look at what we have, before I come back to the issue of what archaeometallurgy is. Well, there are four new books, two explicitly concerned with islands, giving the excuse for the title of this review. Three are hard bound, serious looking, and one small, soft bound. One on tin, one on gold, one on steel, and one on The archaeometallurgy of the Asian Old World. Being somewhat traditional I decide to tackle them in chronological order as far as possible.

The archaeometallurgy of the Asian Old World is a collection of seven papers, each aiming to give an overview of a particular research topic or region. In order to understand the selection of those topics covered here -- and hence also the absence of others -- one has to read the Introduction. What we are seeing is the American half of the proceedings of a USA-USSR meeting on `The Development of Ancient Metallurgy in the Old World', held in 1988 in Georgia. The late 1980s were a fascinating period, perestroika looming and booming; but the collapse of the Soviet Union soon after the meeting, and the pressing change in the life of many eastern colleagues, effectively prevented the complete assemblage of the proceedings. Thus, the book presents only contributions of western colleagues, plus a translation of a brief summary of the conference as published shortly after it in Sovetskaya arkheologiya. The papers are arranged in geographical order. The first two, by James Muhly on `Copper and bronze in Cyprus and the Eastern Mediterranean' and by Jane Waldbaum on `The coming of iron in the Eastern Mediterranean', cover an area which I at least have some difficulties in recognizing as Asian. But they provide a well-known starting point from where to move further east, through `Aspects of early metallurgy in Mesopotamia and Anatolia' by Tamara Stech and `The development of metal production on the Iranian Plateau' by Vincent Pigott, to `Metal technologies of the Indus Valley Tradition in Pakistan and Western India' by Jonathan Kenoyer & Heather Miller, to `The Early Iron Age in South Asia' by Gregory Possehl & Praveena Gullapalli and finally to `The transition to iron in Ancient China' by Bennet Bronson. It is really a pity that the eastern counterpart of this collection of papers is lacking. Judging from the summary provided, these would have offered a remarkable amount of additional data, both geographically and in the methodological approach. Much work was apparently presented on Caucasian metallurgy, with its highly significant bearing on the development in Western and Southwestern Asia. Current research by a number of scholars of the metallurgy in Anatolia and the Levant provides increasing evidence for interaction with -- if not influence by -- the metallurgy in the Caucasian region. But alas, we don't have them here.

There seems to be a general consensus among the papers that we are interpreting a far too limited database, in particular when the very early periods are concerned. Much of the hypothesis put forward, even for late developments such as the transition from bronze to iron, is apparently bound to be subject to considerable change as soon as new information and data becomes available. Thus, the call is in unison for new and further research, quite often explicitly for metallographic studies of artefacts from well-dated contexts. Apparently they do exist, but heavily guarded in collections, and hence almost as good as not excavated. But similarly, there is a pressing need for many more `slag studies', i.e. research into the primary and secondary production methods involved in the creation of such artefacts. Here, the problem is not the inaccessibility of material, but the lack of (funded) research -- and scientists willing and able to do it. The archaeologists interested in metals -- and there are more of them around than there are scientists active in archaeometallurgy -- obviously do their job, enthusiastically interpreting and re-interpreting what limited data they have. I should probably add that the manuscripts for this volume date mostly from 1996 to 1998, and are thus much more recent than the date of the conference may suggest. In general, it is a valuable compilation of the `state of the art' with more emphasis on Asia proper than often found elsewhere.

The second book to discuss here, King Croesus' gold, is very different. This volume addresses a rather specialized issue of archaeometallurgy, namely the refining of gold, in almost every minute detail which the well-equipped laboratory and the experienced staff of the Department of Scientific Research of the British Museum (with contributions by Mike Cowell, Paul Craddock, Duncan Hook, M. Humphrey, K. Hyne, Nigel Meeks, Andrew Middleton) and collaborators in Turkey (A. Geckinli and Hardy Ozbal) could muster. Yet, specialized as the topic may appear, it certainly has its overriding relevance, in that only the refining of gold -- and in particular its separation from the main `contaminant', silver -- enabled the development of coins and currencies, the breathing air of any `serious' economy. This very topic -- the realization first that almost all gold in nature is diluted by various and often considerable amounts of silver, and then the problem of devising a method to part the two -- struck me as an intriguing issue in archaeometallurgy more than 10 years ago. Of course, as Prof. Bachmann quite often pointed out to me, we knew all the time how it was done; after all, the principles of chemistry and its ancestor metallurgy have not changed. And yes, there are the notes in passing by various classical authors, and the rather extensive descriptions from early Medieval times onwards. But for all the mind-blowing quantity of gold mined and processed in the Old World throughout the ages, from the Nile Valley through the Iberian peninsula to Central and Eastern Europe and into Western and Central Asia -- here is the first and only well-researched and published archaeological evidence for it, with many interesting side-tracks for the recovery of the silver from the debris (the massive furnace walls contained silver metal in the order of several percent, not to mention the ceramic of the parting vessels themselves), through the proof for the re-working of some earlier, initially not refined, gold coins, up to a detailed presentation of the numismatic context (by Andrew Ramage), and the scientific investigation of the related ceramic materials, pots and furnace remains. In its presentation of all this detailed work, including the circumstances of the discovery and excavation of the material in the 1960s, replication experiments of the process, a comprehensive discussion of other methods of parting and refining of gold used elsewhere, it may well go beyond the interest of the majority of the readers of this journal. Nevertheless, it is an exemplary scientific investigation of unique archaeological material. In my opinion, at least, it is certainly much better to publish more detail than immediately necessary, than to publish a hypothesis or interpretation without the underlying data. In this way, one can easily skip any part, but it is still available. In this particular case, however, I would maintain that a great deal of the book is good reading anyway, even if it is highly specialized. If only it had been published 10 years ago, when the work was basically completed....

Early iron and steel in Sri Lanka already from the outside is by far the most impressive of the four books in the bag. More than 400 pages of two-column A4 text (including 150 pages of catalogue in the appendices) are waiting for the reader, very well illustrated with drawings, half-tones and colour photographs in the text. It starts as a relatively unexciting printed version of a doctoral thesis (carried out during the 1990s at the Institute of Archaeology, London, several years before I took up work there), but soon one is lured into the fascination of a landscape which reveals its intense and varied archaeological heritage only during a survey before a huge dam development -- discovered to be destroyed. The first 50 pages give the framework of the study and the setting of the area, necessary background information against which the real stuff which follows has to be seen. The next hundred pages or so are really it. The discovery, interpretation and explanation of a metallurgical phenomenon, the so-called west-facing furnaces. I learned archaeometallurgy with the sound belief that there are two ways to operate proper furnaces, namely either by forcing wind into them by bellows, or by using the chimney effect of a tall shaft. Here, we have a third way. These are wind-powered furnaces where the stream of steady winds blowing across and over the furnaces generates an upward sucking system of low pressure, not unlike the aerodynamic system that keeps a jet plane in the air from the airflow across the carefully profiled wings. This low pressure system then sucks air into the furnaces through tuyeres positioned near the front base. Hence, these furnaces are short, built into the ground and always situated just beneath the top of an appropriate hill, facing the wind and allowing a nice lamellar flow across them. They are not circular as any other furnace, but elongated, like a sofa, with a take-away breast of clay around a wooden structure and the series of tuyeres at the base. The sides and backs of the furnaces are cut into the soil, and remain almost unchanged during the smelts. The identification of this supposedly modern principle of aerodynamics in an archaeological context, on a regular scale and developing over half a millennium, quite rightly made it to the cover page of Nature in 1996, and attracted much attention in other news media as well. Here now is the full story, presenting the archaeological evidence as well as the experimental reproduction of the process, with all the necessary scientific recording and observations of the relevant environmental parameters such as wind speeds and directions, level of vegetation, and geomorphological constraints, in well-measured detail.

Beyond this intriguing metallurgical story is a quite remarkable personal story as well. What began as a more or less routine survey of an archaeological landscape turned into a masterpiece of scientific research, basically done by a Ph.D student of archaeology on her own initiative and intuition. Of course, she had scientific advice and support once she had identified the basic principle, to confirm the theory behind her hypothesis. But it is still her own research and success, which since then has been applied to a number of other furnace sites with similar settings and design, such as certain Bronze Age copper-smelting furnaces in the Arabah, which were previously considered enigmatic in their function. A very remarkable feature of the book is the documentation of Gill Juleff's smelting experiments, lavishly illustrated with colour photographs and detailed recordings of wind speeds, furnace temperatures and schematic drawings of flow patterns.

Almost hidden in this ground-breaking work is another jewel, namely a detailed documentation of a sub-recent, small-scale crucible steel industry in southern Sri Lanka. Much has been written about crucible steel manufacture in India and Sri Lanka based on textual indications, and a number of archaeological sites are known, and partly studied, from India. But again, only here is the neat combination of archaeological and ethnographic evidence, together with scientific investigations of related remains (by Mike Wayman, in Appendix D), which is almost unique in its `satisfaction level' to the interested reviewer. This is a lasting and exemplary contribution not only to archaeometallurgy, in terms of process identification and reconstruction, but to archaeology in general for its apt integration of open-minded fieldwork, environmental recording, scientific investigation and archaeological interpretation. None of the individual parts on its own would have been as thrilling as is their combination.

The early British tin industry is quite different from the other three, in that it follows a purely archaeological and historical approach to a metal, pulling together a lot of information for the British tin industry from the beginnings in prehistory to the early modern period. However, it restricts itself to the archaeological evidence for the various mining methods used, from streamworks to underground mining, and for the crushing and beneficiation of the ore, with hardly any discussion of the material which was worked and processed, and its geological peculiarities and relationship to the mining landscape. This lack of `scientific' information became particularly apparent to the reviewer when the smelting of tin is discussed. The 11 pages devoted to this subject manage to avoid the word `slag' almost entirely, and the entire smelting process is reduced to two sentences (p. 129):

`Before the tin could be successfully smelted the furnace had to reach a temperature of at least 1150 [degrees] c [sic!] and this was achieved by blowing air through the furnace using water powered bellows. Once the tin had become molten, it flowed from the furnace into a float stone and from here was ladled into a bevelled rectangular trough cut into a granite boulder called a mould stone, in which it cooled to form an ingot of white tin.'

I am well aware of the scarcity of archaeological tin slags, not only in Britain. But then, there are a number of studies available, investigating both prehistoric and Medieval/Early Modern tin slags from Britain. They are, admittedly, not very conclusive regarding the ways and means of smelting, but they do add important and significant information about the efficiency of a process that dealt with a rather expensive commodity. Seeing now tin smelting reduced to an operation without fuel, flux and slag, but with the same over-emphasis on the mould stone that runs through the whole book, is somewhat disappointing. On the other hand, I hasten to say that the compilation of information and historical data given certainly makes this book a worthwhile read. It is only in the stark contrast to the really integrated approach of the previous book that this one falls behind. In all fairness, there is enough merit in the present book, not least the good illustrations, many of them in colour, of a number of archaeological and building features which are otherwise difficult to understand, and a guide to sites to visit. Whether such publicity of archaeological sites is a positive thing (in terms of `public archaeology' and the accessibility of archaeology to local communities), or rather poses a threat to them, may be discussed elsewhere.

Coming back to the initial question -- an island? -- archaeometallurgy as a science may have been performed too often in isolation, on a virtual island, concerned only with the development of ever more `powerful' tools to analyse ever more exotic trace elements. To a great extent, research funding strategies are to blame for this rather than individuals. These books now prove that there is, even at the `grass roots' level of Ph.D work, the possibility for a full integration of scientific, metallurgical, research methods in archaeological projects, answering archaeological questions -- applying methods rather than developing them. In the first book, archaeologists discuss at length the interpretations that would be possible if only enough scientific data would be available. The next two books prove the exciting possibilities of such integrated work by example. In one of them, it is mostly scientists presenting and discussing their own data, much in the tradition of a history of metallurgy. In the other, an archaeologist presents and discusses her own scientific data, pushing home archaeology. These are three different approaches to archaeometallurgy, all equally valid, and by far not covering the full range of the science (or art, as I prefer it to see). The fourth, really, is concerned with the archaeology of a metal, rather than archaeometallurgy; it is free of any scientific input. It will be a long time before we understand the archaeometallurgy of tin, be it in Britain or elsewhere. Archaeometallurgy is not an island, but an integral and inseparable part of archaeology. Where interaction occurs, the benefit is mutual, and often exciting, as demonstrated in two of these books.

Reference

JULEFF, G. 1996. An ancient wind-powered iron smelting technology in Sri Lanka, Nature 379 (6560): 60-63.

THILO REHREN, Institute of Archaeology, University College London, 31-34 Gordon Square, London WC1H 0PY, England. Th.Rehren@ucl.ac.uk