Preserving the Status Quo: Britain,the United States,and Bolivian Tin, 1946–56

This article analyses the relationship between Britain, the United States, and Bolivia in the context of the tin nexus after the Second World War. While the connection between Britain and Bolivia was long-standing - Bolivian tin had been shipped to Britain since the nineteenth century - it extended far beyond simple bilateralism. Such was the intricate web of connections in the global tin industry that any rupture in the Anglo-Bolivian relationship would have fundamental ramifications on the equilibrium of the industry, and, in turn, Britain's predominant position within it. The United States had overtly challenged Britain's dominance during the Second World War by constructing a smelter to be supplied by Bolivian ores. Despite the financial exigencies of the post-war period, the profound upheavals in the domestic Bolivian tin industry, and the contentious, destabilising tin-procurement policy pursued by the United States, Britain was determined to confront this threat. By actively seeking to preserve its long-term contract for Bolivian tin, Britain was able to maintain its predominance in the post-war global tin industry. At the same time, Bolivia deftly utilised Anglo-American rivalry to ensure more than one outlet for its most critical export commodity.     

The key role of zinc,tin and lead in copper-base objects from medieval Talgar in Kazakhstan

Metallurgical examination of brass and bronze objects from the medieval (AD 9th–13th century) site at Talgar in Kazakhstan shows that they were mostly cast from the quaternary copper–zinc–tin–lead system with some exceptions that were forged from binary copper–zinc alloys. Evidence is found that brass was produced in the cementation process and that the addition of tin and lead to the parent brass was considered beneficial in casting but was strictly avoided in forging. The mutual effect of zinc, tin and lead for better casting and the advantages of the binary copper–zinc alloys in forging seem to have been the major factors driving the establishment of this unique brass tradition in a society with probably limited access to tin.     

The Intentional Use of Lead–tin Orange in Indian Islamic Glazes and Its Preliminary Characterization

We describe the historical appearance, composition and texture of a little‐known orange pigment in 17th‐century northern India. The pigment shares similarities with lead–tin yellow type II, but has between 6 and 7 wt% zinc oxide instead of silica as a minor element in its structure, in addition to the dominant lead and tin oxide. The consistency of its occurrence and composition across several important and highly decorated monuments and relatively wide chronological and geographical ranges of use indicate the controlled and intentional production of this pigment. We propose to use the name lead–tin orange for this material, indicating its similarity to lead–tin yellow but highlighting its independent character and distinct colour.     

TIN ISOTOPY—A NEW METHOD FOR SOLVING OLD QUESTIONS

Tin was a vital commodity in times past. In central Europe, the earliest finds of tin‐bronze date to about 2200 bc , while in Greece they are c. 400–500 years earlier. While there is evidence for prehistoric copper mining—for example, in the Alps or mainland Greece, among other places—the provenance of the contemporary tin is still an unsolved problem. This work deals with a new approach for tracing the ancient tin via tin isotope signatures. The tin isotope ratios of 50 tin ores from the Erzgebirge region (D) and 30 tin ores from Cornwall (GB) were measured by MC–ICP–MS. Most ore deposits were found to be quite homogeneous regarding their tin isotope composition, but significant differences were observed between several deposits. This fact may be used to distinguish different tin deposits and thus form the basis for the investigation of the provenance of ancient tin that has been sought for more than a century. Furthermore, the tin‐isotope ratio of the ‘Himmelsscheibe von Nebra’ will be presented: the value fits well with the bulk of investigated tin ores from Cornwall.     

Tin‐Rich Surface Decoration of Chinese Bronzes: A Case Study of the British Museum Collection

In this paper six bronze artefacts of the Eastern Zhou period to Han dynasty (770 BC ‐ 220 AD) with tin‐rich surface decoration in the British Museum collection were studied using a variety of analytical techniques. The decoration patterns include trellis patterns (菱形纹) on two swords of the Yue state, tiger's striped patterns (hu‐ban‐wen, 虎斑纹) on two swords from the Ba‐Shu region, a hexagonal star pattern (六角星纹) on a spearhead of the Wu state, and a cloud‐like pattern on a garment hook. The tin‐rich decorations on those objects were produced by deliberate tinning processes; at least three different tinning techniques were used, including the use of tin‐rich pastes for the trellis pattern of a Yue state sword and for the mottling decoration on the Ba‐Shu swords, amalgam tinning for the hexagonal star pattern on the spearhead of the Yue state, and hot tinning for the cloud‐like pattern of the garment hook. Different tinning techniques could have been applied to produce similar tin‐rich decoration patterns, and vice versa, a single tinning technique could have been used to produce different tin‐rich patterns on different objects.     

A Late Bronze Age Shipwreck with a Metal Cargo from Hishuley Carmel,Israel

A 13th‐century‐BC shipwreck site, Hishuley Carmel, is described and discussed. It provides direct evidence for marine transport of copper and tin along the Israeli coast and may indicate inland and maritime trade‐routes of metals in the Mediterranean. The shipwreck represents a supply‐system providing the demand for bronze in the Levant. Trace‐elements and lead‐isotope analysis suggest that the copper came from Cyprus, similarly to bun and oxhide ingots from Uluburun. The source of the tin cannot yet be ascertained. The medium‐size ship was probably grounded and wrecked during a storm. Some of the cargo may have been salvaged in Antiquity. © 2012 The Authors     

个旧锡业开发与生态环境变迁(1890-1949)

随着1889年蒙自的开关,尤其是1910年滇越铁路的全线通车,极大地改善了云南的对外交通运输条件,推动了个旧锡业的迅速发展。在1890年至1949年的60年间,个旧共生产大锡323042吨,个旧锡业也取代铜业成为近代云南的矿业支柱。个旧锡业在推动云南矿业发展的同时,也对个旧及周边地区生态环境产生了巨大的影响。在1890年至1949年的60年间,个旧地区仅土法炼锡就至少消耗45万吨以上木炭。个旧、蒙自、建水、开远和石屏五县地区天然林平均覆盖率从清初的90%锐减至1940年的2.98%,近三百年间减少了80%以上,个旧锡业开发显然是五县天然林平均覆盖率急剧减少的重要原因。同时,锡矿的大量粗放开采和冶炼,也污染了个旧地区的土壤、水源和空气环境,带来了环境污染问题,影响了当地民众尤其是矿工的身体健康。因此,锡业开发是导致近代个旧及周边地区生态环境变迁的重要原因。     

十九世纪的华人私会党与马来亚锡矿业

十九世纪马来亚锡矿业的发展与华人私会党息息相关 ,华人私会党力量的消长决定了锡矿业的起落沉浮 ,二者的历史荣衰与共。本文从十九世纪华人私会党对马来亚锡矿业发展的影响这一角度出发 ,分三个时期 (一、十八世纪末至十九世纪四十年代末 :马来亚锡矿业的初步发展时期 ;二、十九世纪五十年代至八十年代末 :华人私会党垄断锡矿业时期 ;三、十九世纪九十年代至二十世纪十年代 ,华人私会党对锡矿业的影响衰落时期 )阐述了华人私会党与马来亚锡矿业之间的关系 ,探讨了私会党对锡矿业发展带来的利与弊。     

安徽南陵出土部分青铜器研究

安徽省南陵县是长江下游地区最早而且规模最大的冶炼中心之一,其古代矿冶遗址可上溯至西周晚期。本研究对南陵出土的不同年代和类别的青铜器样品进行了金相检测及合金成分定量分析。结果表明,只有容器存在铜铅二元合金和铜锡铅三元合金,但是热锻淬火的容器却不含铅,含锡量恰好位于适合该工艺操作并具有良好性能的区间。兵器、工具、车马饰均为铜锡二元合金,说明当时的工匠对于合金成分配比与性能的关系有明确的认识。越式鼎腹部样品具有热锻淬火马氏体组织,同样的金属结构还见于汉代铜锣等乐器、峡江地区战国中晚期青铜剑、江都大桥镇南朝青铜器窖藏出土的多件青铜容器,而镇江地区出土吴国青铜戈则具有铸造淬火组织,工艺稍有差别。这些器物中发现高锡青铜淬火组织不是偶然的,高锡青铜热锻淬火技术至少可以上溯至春秋战国时期,用以改善高锡青铜的机械性能。     

东周楚式戈斑纹的成分与相组成

为探讨东周楚式戈斑纹的处理技术,采用金相显微镜、SEM、EDS、EBSD研究了上海博物馆藏的楚式斑纹戈的成分、显微组织和相组成,讨论了其制作工艺.结果表明:东周楚式戈富锡层厚度不均,以十余μm左右的厚度居多,最多处由4种不同物相组成,分别为η相、ε相、σ相及(α+δ)共析相.富锡层与基体之广日j没有明显的分界线.与现有其它富锡工艺研究成果进行比较,认为此件楚式戈与其它地域的富锡技术具有共同的工艺特征,应为热镀锡工艺.但在工艺参数掌控方面应呈现地域上的差异.     

The production technology of Iznik pottery—a reassessment*

Previous research has established that Iznik pottery differs from other Islamic stonepaste pottery in that its stonepaste bodies contain lead oxide as well as soda and lime, and that a significant proportion of the tin oxide in its glaze is present in solution rather than as tin oxide particles. In order to better understand these distinguishing features, the chemical compositions and microstructures of Iznik pottery and tile samples, together with those of lumps of glass found in association, were investigated using both scanning electron and optical microscopy. These data have been supplemented by the study of replicate lead–alkali glazes produced in the laboratory with a range of different compositions. The results demonstrate that separate soda–lime and high‐lead glasses were used in the production of Iznik stonepaste bodies, and that the total glass contents of the bodies were significantly higher than those quoted by Abū’l‐Qāsim, who was writing in about ad 1300. The very high purity of the lead–soda Iznik glazes indicated that the alkali flux used was either a purified plant ash or an as yet unidentified mineral source of soda. Replication experiments established that the high solubility of tin oxide in the glaze was due to the high purity of the glaze constituents. Furthermore, it is suggested that tin oxide was added to the glaze in order to give it a very slight opacity and thus obscure any blemishes in the underlying body.     

The Medieval and Early Modern Cornish Stamping Mill

Abstract

The exhaustion of the richest alluvial tin deposits led to development of lode tin. Stamping mills were developed to crush the ore and although considerable archaeological and documentary work had been carried out in neighbouring Devon, little research had been undertaken in Cornwall. The excavation of two mills at Colliford, the survey of further examples at Retallack and an extensive search of documentary evidence has allowed an appraisal of this aspect of the early Cornish tin industry. Much work still remains, but now it is possible to be much more positive about the character of the surviving field evidence, the potential for excavation and the need to develop a research strategy.     

Rediscovering famous assemblages: A rare Bronze Age crucible from El Argar,Spain

A rare open shallow crucible from the British Museum collection, excavated at the Bronze Age site of El Argar in south-east Spain by Louis and Henri Siret, was studied using X-radiography and scanning electron microscopy. The crucible has relatively thick walls, a spout and a non-refractory fabric. It was used for melting copper alloys for various possible purposes, such as alloying, refining, recycling or before casting, at around 1100°C. Both arsenic and tin were detected in various places and concentrations in the analysed specimens. This crucible could have been used during the period of transition from arsenic-rich copper to tin bronzes in the El Argar culture, or used for the recycling of arsenic-rich copper artefacts being alloyed with tin to produce tin bronzes. This melting crucible is a rare example of its kind to have been investigated scientifically, as most crucibles from contemporary sites on the Iberian Peninsula are generally associated with smelting. This study has also crucially shed more light on the types of alloys and variety of activities undertaken during that transitional period between the use of arsenical copper and tin bronzes in this region.     

IDENTIFICATION OF FORGERIES BY MEASURING TIN ISOTOPES IN CORRODED BRONZE OBJECTS*

The reliable identification of fakes consisting of bronze often presents problems, because traditional methods such as stylistic studies, optical microscopy, chemical analysis or X‐ray diffraction of the corrosion may not be conclusive. We present a method that is based on the comparison of the tin isotope ratios ¹²²Sn/¹¹⁶Sn and ¹¹⁷Sn/¹¹⁹Sn in the metal and in the adherent corrosion layer. An artificial patina is usually generated within a short time period. It has been observed that such a procedure leads to a depletion of the light tin isotopes in the corrosion layer, while in naturally corroded authentic archaeological objects no isotopic fractionation has been detected. The method has also been applied to archaeological objects and it could be confirmed, among other examples, that the famous ‘Sky Disc of Nebra’ is authentic.     

THE ISOTOPIC COMPOSITION OF TIN IN SOME ANCIENT METALS AND THE RECYCLING PROBLEM IN METAL PROVENANCING

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 $0.1% in the ratio¹²² Sn/¹¹⁶. 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.     

SEM and electrochemical characterization of bronze artifacts from the Francavilla archaeological site

The excavations in the necropolis of the Francavilla Marittima archaeological area, in Calabria, have brought to light the rich burial artifacts and materials, dated between the end of the ninth and sixth centuries BCE. SEM/EDS analysis was conducted on some sections taken from a bronze artifact classifiable as an armilla or fibula fragment. Our aim was to elucidate the nature of the corrosion processes acting on the specimen. SEM investigation detected the segregation of tin towards the outer layer and a depletion of the copper content in the same region. Furthermore, the elemental distribution maps of the sections analyzed evidenced the presence of chloride ions in the border area between the corrosion patina and the metal alloy. Such anion migration of chloride ions into the interior of the alloy leads to a particular variant of the type of corrosion of structure that in the literature has been identified as structure I.A cavity electrode designed for electrochemical measurements of powders was used to perform cyclic voltammetry experiments devoted to explore the activity of the patina covering the surface of the bronze fragment. The surface layer consists mainly of tin and tin oxides; the layer immediately beneath it contains copper oxides. An increase of reactivity was shown in an acidic environment. The activity of the patina is greatly reduced at pH 5 and appears to be zero at neutral pH.     

THERMOLUMINESCENCE DATING OF A CRUCIBLE FRAGMENT FROM AN EARLY TIN PROCESSING SITE IN TURKEY

Archaeological exploration in the Taurus mountains at Göltepe in south-central Turkey has uncovered a site indicating the presence of extensive tin ore mining and smelling operations The most recent find of smelting crucible fragments allowed for a thermoluminescence-hased age determination spanning a late fifth to early third millennium BC date. This result is consistent with a number of radiocarbon dates derived for charcoal also found at the site. The importance of this site relates to the possible tin production and subsequent trade with southwestern Asia which would have provided this otherwise scarce ingredient to bronze technology in that area. This date is directly for crucible material and thus confirms the antiquity of tin smelting at Göltepe.     

Egyptian Blue cakes from the Ayanis fortress (Eastern Anatolia,Turkey): micro-chemical and -structural investigations for the identification of manufacturing process and provenance

The microstructure and chemical composition of blue cakes, found during the archaeological excavation of the Ayanis fortress (Eastern Anatolia, Turkey), have been investigated by means of scanning electron microscopy combined with energy dispersive spectrometry (SEM–EDS), X-ray diffraction (XRD), micro-Raman (μ-Raman) and optical microscopy (OM) techniques. The analysis of the Ayanis cakes has shown the presence of Egyptian blue (i.e. CuCaOSi₄O₁₀, cuprorivaite), as the major component, intermixed with minor amount of other phases such as partially reacted quartz grains, an adherent glass phase and copper oxides. Since the finding of Egyptian Blue in Turkey has been never reported so far, great attention has been paid to its characterisation. The micro-chemical and micro-structural investigations of the Ayanis cakes have allowed a further insight into the manufacturing process and into the sources of the starting materials. The results of the characterisation have revealed some significant differences with respect to Egyptian blue cakes found in Egypt and Mesopotamia, as for instance the absence of tin excluded the use of bronze scraps or filings in their preparation differently from those produced in Egypt and Mesopotamia. Furthermore, some peculiarities of Egyptian blue found in Ayanis, as the detection of zinc in the cakes, allow to put forward the hypothesis of a local production considering that a large part of the bronze artefacts found at the Ayanis fortress is characterised by the presence of zinc as minor alloying element.     

COPPER ALLOYS FROM THE ‘ENOT SHUNI CEMETERY AND THE ORIGINS OF BRONZE METALLURGY IN THE EB IV – MB II LEVANT

Tin bronze replaced arsenical copper as the preferred alloy in the Levant for reasons that have long been debated. Found almost exclusively in graves, these two types of copper alloys share nearly identical mechanical properties. The Bronze Age cemetery of ‘Enot Shuni has yielded the first metals ever analysed from an uninterrupted stratigraphic sequence in the Levant, spanning the earliest adoption of tin bronze from the Early Bronze Age (EB) IV through the Middle Bronze Age (MB) II (c. 2300–1530 bc ). SEM–EDS analysis of these artefacts, combined with a compositional meta‐database of all previously published EB IV – MB II alloys, reveals diachronic alloy progression as selected by populations of the Levant. It has long been qualitatively understood that bronze became the primary alloy by the MB II. These results verify this trend and quantify human demand, showing that tin importation increased by 103% and arsenic content decreased by 49% throughout these periods. This shift in technological choice is attributed to cultural reorientation from the Egyptian to Mesopotamian sphere of influence, as well as to tin's appreciable fuel efficiency over pure copper and arsenical copper in light of unprecedented timber shortages.     

ERZGEBIRGE TIN: A CLOSER LOOK

Summary. The publication of Muhly's Copper and Tin in 1973 was an important contribution to the study of the metals trade in antiquity. However, in his section on Central and Eastern European tin ore deposits, he ruled out the possibility, on geological grounds, that the Erzgebirge might be a source of tin ore in the Bronze Age. This paper is not in agreement with this conclusion, and attempts to reinstate the Erzgebirge as a viable source of tin in antiquity.