A better shade of black: effects of manufacturing parameters on the development of ancient black bronzes

Alloys with controlled contents of Sn, Ag and Au, were treated with methods and solutions that mimic those used in ancient and traditional procedures for the production of black bronze. Examination of the resulting patinas with colorimetry, SEM-EDS, TEM, Raman Spectroscopy, and XRD revealed no systematic differences according to fabrication method, whereas patina homogeneity and colour in those alloys which did not contain precious metal were affected by superficial work. Patina microstructure determines adherence and coverage, and depends upon solution used irrespective of the alloy composition, but the colour of the patina is mainly related to alloy composition. Gold promotes the development of cuprite, slowing the oxidation to tenorite in the corrosion process. Gold additions produce a more uniform patina as well as a desirable blue-black tone which is likely to have been a factor in alloy selection

La fouille archéologique du quartier Velotte à Montbéliard : nouvelles données sur des opérations de chimie oubliées

La publication de fouilles archéologiques anciennes menées en 1993 et 1994 à Montbéliard, rue Velotte au bourg Saint-Martin, avaient négligé des objets se rapportant à la distillation et à la métallurgie. L'étude physico-chimique présentée ici d'une petite coupelle, ou récipient réfractaire destiné à affiner les métaux précieux, associée à une enquête dans les archives permet de mettre en évidence un atelier d'essai de minerais de cuivre argentifère vers 1600

Some problems and potentials of the study of cupellation remains: the case of post-medieval Montbéliard, France

Bone-ash cupels are increasingly identified in medieval and later archaeological contexts related to the refining of noble metals in alchemy, assaying, jewellery or coin minting. These small finds may provide information on metal refining activities, the technical knowledge of different craftspeople, and the versatility of laboratory practices, which often differed from the standard protocols recorded in metallurgical treatises. This paper is centred around a late 16th-early 17th century cupel excavated in Montbéliard, France. The analytical study by optical microscopy, ED-XRF and SEM-EDS allows the cupel to be ascribed to the assaying of the silver content of an ore sample, which is supported by local historical and geological information. The manufacture of the cupel, made of a mixture of wood ash and bone ash, is also addressed, as well as the limited technical efficiency of the operation. This leads to a wider discussion of different recipes for the manufacture of cupels, documented historically and archaeologically, and involving the combination of various raw materials such as bone, wood ashes and clay. This variability raises interesting questions about the existence of diverse technical traditions, and the material properties and performance of different cupels in their specific contexts. In order to facilitate comparisons, we propose that the study of cupellation remains is most informative when it combines microscopy and microanalysis. The role of experimental approaches to these questions is also discussed.Les coupelles en cendres d'os sont de plus en plus nombreuses à être reconnues dans des fouilles médiévales ou modernes. Elles sont utilisées pour l'affinage de métal précieux par les alchimistes, les essayeurs, les orfèvres ou encore les monnayeurs. Ces artefacts peuvent fournir des informations sur les techniques d'affinage, les savoir-faire et les pratiques de l'atelier qui souvent sont différentes des recettes et procédés décrits dans les textes métallurgiques. Cette étude concerne une coupelle de la fin du xviesiècle ou du début du xviie siècles découverte en fouille à Montbéliard (France). Les analyses, par microscopie optique, MEB-EDS, et ED-XRF permettent d'associer la coupelle à l'essai d'un échantillon de minerai de cuivre argentifère, hypothèse confirmée par l'étude des sources écrites et géologiques locales. La fabrication de la coupelle, faite d'un mélange de cendre de végétaux et de cendre d'os est également abordée comme les limites et l'efficacité de l'opération. Ces résultats mènent à une discussion plus large sur les différentes recettes de fabrication de coupelle grâce aux sources écrites et archéologiques qui indiquent des matières premières diversifiées comme la cendre d'os, la cendre de végétaux et la terre. Cette variabilité soulève des questions intéressantes sur l'existence de traditions techniques diverses ainsi que sur les propriétés et l'efficacité de ces coupelles. À des fins comparatives, nous concluons que l'étude de ces artefacts est plus efficace en associant la microscopie et la microanalyse. Enfin, le rôle des approches expérimentales à ces questions est également discuté

Of forming, gilding and intentionality in Pre-Columbian goldwork: analytical characterisation of artefacts from the Museo del Oro, Bogotá

The analytical study of ancient metalwork is a useful strategy to characterise past technologies, but in contrast with other American metalworking traditions this approach has been relatively limited in the context of pre-Columbian Colombia. As a contribution to this emerging research area, this paper presents the results of a compositional and technological study on seven gold alloy artefacts from the collections of Museo del Oro, Bogotá D.C., Colombia, focusing on alloy selection, forming technologies and surface treatments. The artefacts come from four different metalworking regions, and include personal adornments, a votive figure, and an unidentified sheet fragment. Surface imaging and microanalyses were carried out by scanning electron microscopy with energy dispersive spectrometry (SEM-EDS). X-ray mapping was undertaken to gain further insight into depth and nature of surface treatments and internal microstructures. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) data was also collected, enabling cross-analytical technique comparisons and the collection of trace element data. The results allow the identification of alloying technologies and forming methods, as well as the characterisation of corrosion products and gilding layers, and discussion of the intentionality of the latter where present. The case studies are discussed in relation to the existing pool of evidence and used to assess the potential for further analyses on the region’s metalwork.Institute of Archaeometallurgical Studies, MSc Scholarship Arts and Humanities Research Council, PhD Studentship, AH/L503897/1 British Academy, SG-5424

Risk Analysis by Age on the Burden of Meningococcal Disease in Spain.

We conducted an age-based risk analysis of meningococcal disease in Spain to provide prospects on a rational vaccine schedule in pediatrics. We used the National Hospital Registry to estimate meningococcal hospitalization rate. Population census for each year was used as the denominator in computing the hospitalization rate. We computed the odds ratio of each age using 5-year-old children. There was a dramatic decline in risk in 1 year (OR 0.58) to 4 years of age (OR 0.21). The risk continued to decline until 13 years old. Afterward, it had a minimal upward trajectory observed at 14–17 years old (OR 0.08). Infants and adolescents are at continued risk of invasive meningococcal disease in Spain. The highest risk occurs in infants. Surveillance data, together with evidence on long-term immunogenicity and capacity for herd effect, should be considered for a more relevant immunization schedule