The history of silver refining in New Spain, 16c to 18c: back to the basics

The refining of silver ores in New Spain was defined by the chemical nature of the silver ore. Argentiferous galena (lead sulphide) could only be refined by smelting (36% silver produced), irrespective of silver content, and amalgamation (64%) could only be applied to the silver sulphide ores. Both processes were transferred from Europe, but amalgamation was transformed by local expertise from a recipe of limited application to an industrial-scale solution for refining sulphidic silver ores. Its implementation shaped the environmental history of colonial silver refining in the New World. Mercury was consumed mainly through its chemical conversion into calomel, with minimal emissions of volatile mercury. Waste silt and liquid mercury in the soil and waterways were its main legacy. Smelting created a greater impact on the environment of New Spain, via lead in lead fumes as the main heavy metal issued to the air, and its depletion of woodlands. This article argues that a technical analysis of period refining practices in New Spain reorients our understanding of Spain’s imperial relations with its New World colonies, of the role of local knowledge in a global economy of silver production, and of environmental issues in colonial history. It thus speaks to the problem of unpacking the complex web of relations that composed early European imperialism, in which were enmeshed commodities such as silver, cotton and sugar.     

Bone diagenesis in the European Holocene II: taphonomic and environmental considerations

We have applied cluster analysis to mercury intrusion porosimetry data from 219 archaeological bones (121 human and 98 animal) and soil chemistry data from 219 accompanying soil samples (1 per bone sample), to investigate the influence of soil chemistry on bone preservation. The samples chosen for the study were obtained from sites ranging in time from the pre-modern to the Mesolithic and were representative of burial environments across Europe (from the Baltic to the Mediterranean). These results represent the single largest database for archaeological bone preservation in the European Holocene to date and demonstrate the potential for large-scale diagenetic studies to help develop long term preservation strategies for our European heritage. Despite the variety of sites and environments, bones could be categorised into only four main diagenetic types. Furthermore, soil chemistry appears to significantly affect only one type of preservation, the pathway characterised by loss of mineral. In neutral to basic soils, taphonomy and in particular the differences between the treatment of human and animal remains, becomes the dominating factor in determining preservation. Using these results, strategies for heritage management of archaeological sites can be suggested; grouping sites into those requiring immediate excavation and those where in situ preservation is viable.     

Retrograde P–T evolution and high temperature–low pressure fluid circulation in relation to late Hercynian intrusions: a mineralogical and fluid inclusion study of the Charroux-Civray plutonic complex (north-western Massif Central, France)

The calc‐alkaline plutonic complex from Charroux‐Civray (north‐western part of the French Massif Central) displays multiphase hydrothermal alteration. Plutonic rocks, as well as early retrograde Ca–Al silicate assemblages, which have crystallized during cooling and uplifting of the plutonic series, are affected by multiphase chlorite–phengite–illite–carbonate alteration linked to intense pervasive fluid circulation through microfractures. The petrographic study of alteration sequences and their associated fluid inclusions in microfissures of the plutonic rocks, as well as in mineral fillings of the veins, yields a reconstruction of the P–T–X evolution of the Hercynian basement after the crystallization of the main calc‐alkaline plutonic bodies. This reconstruction covers the uplift of the basement to its exposure and the subsequent burial by Mesozoic sediments. Cooling of the calc‐alkaline plutonic series started at solidus temperatures (～650°C), at a pressure of about 4 kbar (1 bar = 10⁵ N m^?2), as indicated by magmatic epidote stability, hornblende barometry and fluid inclusion data. Cooling continued under slightly decreasing pressure during uplift down to 2–3 kbar at 200–280°C (prehnite–pumpellyite paragenesis). Then, a hot geothermal circulation of CO₂‐bearing fluids was induced within the calc‐alkaline rocks leading to the formation of greisen‐like mineralizations. During this stage, temperatures around 400–450°C were still high for the inferred depths (～2 kbar). They imply abnormal heat flows and thermal gradients of 60–80°C km^?1. The hypothesis of the existence of one large or a succession of smaller peraluminous plutons at depth, supported by geophysical data, suggests that localized heat flows were linked to concealed leucogranite intrusions. As uplift continued, greisen mineralization was subsequently affected by the chlorite–phengite–dolomite assemblage, correlated with aqueous and nitrogen‐bearing fluid circulations in the temperature range of 400–450°C. In a later stage, a continuous temperature decrease at constant pressure (～0.5 kbar) led to the alteration of the dolomite–illite–chlorite type in the 130–250°C temperature range.     

Was He Murdered Or Was He Not?—Part I: Analyses of Mercury in the Remains of Tycho Brahe

World‐renowned Renaissance astronomer Tycho Brahe died on 24 October 1601, after 11 days of illness. Several conspiracy theories regarding his death have been aired, the first shortly after his death by William Shakespeare in the play Hamlet, published in 1603. A key factor in the still lively debate is whether he was administered mercury—as medicine by his own hand, or as poison by an unfriendly hand. In 2010, Brahe's grave was reopened and samples of his bones, hair, teeth and the textiles were procured and analysed. Here, we present evidence that Brahe was not administered lethal doses of mercury.     

气候对中国古代塔砖材料性能劣化影响的研究

在气候影响下,塔砖材料性能的劣化加剧了中国古塔结构的损伤,减少了古塔的结构寿命。为此,课题选择两个极具代表性的中国古代砖塔—1500年历史的嵩岳寺塔和1200年历史的法王寺塔进行同一性研究,欲证明两塔在地理位置、环境气候、形制、塔体古砖制造原料和制造工艺等方面均具有很强的相似性和同一性。采用X射线荧光光谱法分析了两塔塔砖的材料成分,采用压汞法对两塔塔砖材料的孔隙率、孔隙结构和孔隙分布特征进行了实验。两塔塔砖材料实验结果的差异证明:在公元5世纪到公元8世纪的300年气候影响下(该气候为自然营力而非实验室人工模拟),塔砖材料孔隙率的增大是导致中国古代塔砖性能劣化的主要原因,大约30%左右的孔隙从小于1000nm孔径发展扩大到10000～50000nm孔径是塔砖材料孔隙率增大的主要表现形式。因此,预防小孔径孔隙(小于1000nm)在气候影响下发展扩大的防治措施应该成为中国古代砖塔保护工作的研究重点。同时,对因塔砖材料性能劣化而产生的古塔塔体的表观特征进行了分析,分析结果有利于中国古代砖塔的保护。     

Fluidized sandstone intrusions as an indicator of Paleostress orientation, Santa Cruz, California

The late Miocene sandstone intrusions of northern Santa Cruz County, California, are the largest subaerial exposures of clastic intrusions on earth. The intrusions are sourced from a sandstone, underlying mudstone, accumulated in an outer shelf to upper slope environment. Dikes are the most frequent intrusion type, reach the greatest thickness and tend to strike north‐east and dip steeply. One giant dike is more than 150 m wide. Sills are least frequent, locally > 8 m thick and have no clear preferred geographical distribution. Clustered intrusions are commonly < 10 cm thick and mostly composed of dikes of various attitudes. The majority of the intrusions probably were injected shallowly as some extrude onto the seafloor. The local seafloor extrusion also indicates injection during the deposition of the Santa Cruz Mudstone (7–9 Ma). The intrusions are concentrated at the basin margin. Fluid pressure at the centre of the basin and perhaps hydrocarbons were communicated to the basin margin through the then sand, causing fluid overpressures that contributed to the fluidization and intrusion into the overlying mudstone. Primarily north‐east‐striking, steeply dipping dikes and secondarily, shallowly dipping sills are most significant in terms of regional connectivity of intrusions and physical dilation of the formation. The orientation of the dikes and sills indicates a regional stress field with a horizontal NE–SW maximum and a NW–SE minimum compressive direction. The simultaneous development of dikes and sills suggests similar magnitudes of the minimum and intermediate principal stresses. Preferential weakness along bedding contributed to the development of sills. Palaeomagnetic data indicate no significant block rotation around a vertical axis. The maximum principal stress direction indicated by the intrusions is about 55° to the San Gregorio Fault and about 70° to the San Andreas Fault during the late Miocene. This stress field is similar to the modern stress field and suggests moderate fault weakness.     

Sub‐micron spongiform porosity is the major ultra‐structural alteration occurring in archaeological bone

Total pore volume and pore size distribution are indicators of the degree of post‐mortem modification of bone. Direct measurements of pore size distribution in archaeological bones using mercury intrusion porosimetry (HgIP) and back scattered scanning electron microscopy (BSE‐SEM) reveal a common pattern in the changes seen in degraded bone as compared to modern samples. The estimates of pore size distribution from HgIP and direct measurement from the BSE‐SEM images show remarkable correspondence. The coupling of these two independent approaches has allowed the diagenetic porosity changes in human archaeological bone in the >0.01 µm range to be directly imaged, and their relationship to pre‐existing physiological pores to be explored. The increase in porosity in the archaeological bones is restricted to two discrete pore ranges. The smaller of these two ranges (0.007–0.1 µm) lies in the range of the collagen fibril (0.1 µm diameter) and is presumably formed by the loss of collagen, whereas the larger pore size distribution is evidence of direct microbial alteration of the bone. HgIP has great potential for the characterization of microbial and chemical alteration of bone. Copyright © 2002 John Wiley & Sons, Ltd.     

Getting Started: Objectives and Justifications in the History of Neurology

Contemporary historiographical ideas have the potential to enrich the history written by practicing neurologists. Neurology is a science, and historians of neurology might profit from considering the experiences of historians of other sciences. An explicit consideration of the range of possible objectives, justifications, sources and methods of historical research may open new and exciting avenues of inquiry. Any plausible answer to the question, “What does a historian do when he or she sits down to write history” helps an historian to develop the structure of his or her project. The selection of sources for a historical study is improved, if also expanded, by understanding its aims.     

两件西汉时期鎏金与鎏银青铜器镀层中的金属化合物

采用金相显微分析、环境扫描电子显微镜、X-射线衍射、X-射线荧光对两件西汉时期的鎏金与鎏银青铜马镳进行了分析,揭示了西汉时期鎏金与鎏银青铜器的部分金相学特征和部分金属化合物,研究结果表明我国西汉时期已采用了金汞齐与银汞齐在铅锡铜合金表面火法鎏金和鎏银技术。     

Hair today,gone tomorrow: Analysing potential mercury exposure in 19th-century New Zealand gold miners using Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry

Toxic metal or element exposure has the potential to cause significant negative health effects in human populations. During the goldrushes of the colonial period, mercury amalgamation was one of the most common methods of extracting gold from alluvial deposits or crushed ore, and exposure to mercury was an occupational health hazard. In this study we examine mercury exposure in mining populations from New Zealand’s first major goldrush, which began in Central Otago in 1861. We explore mercury toxicity through laser ablation inductively coupled mass spectrometric analysis of archaeological hair and sediment samples associated with the Tuapeka goldfields. Our analysis highlights ubiquitous low-level mercury exposure on the goldfields, as well as one individual with such high mercury concentrations in their hair that we suspect direct mercury intake, perhaps medicinally, rather than from environmental contamination.