Egyptian faience glazing by the cementation method part 1: an investigation of the glazing powder composition and glazing mechanism

In cementation glazing, for various reasons, there are significant differences between the composition of the glass phases present in the faience microstructure and the glazing powder composition. Furthermore, in this glazing method, the glazing powder should perform more functions, which are: producing a shiny and smooth glaze coating, producing a firm capsule surrounding objects entirely (to prevent adhesion between sintered glazing mixture and the melting glaze coating), and, finally, producing a porous and friable sintered glazing mixture for safe and easy removal of buried objects. It is obvious that these functions also have significant effects on the glazing powder composition and constitution. Therefore, analytical data on faience glass phases are very unlikely to reflect the strict composition and constitution of the original glazing powder properly. Accordingly, the composition and constitution of cementation glazing powder have remained obscure for a long time. These data are particularly crucial factors for cementation replication experiments and, consequently, for our awareness of the ancient faience production. In this paper, a series of cementation replication experiments have been conducted in an attempt to provide further clarification of these issues. In addition, as a comparative indicator for alkali and copper vaporisation, a small piece of rock quartz was placed separately above the glazing powder. After firing, the appearance of the faience objects and quartz pieces and the microstructures and chemical compositions of a select group of samples, obtained using Scanning Electron Microscopy – Energy Dispersive Spectroscopy (SEM-EDS), were investigated. The discussion has focused mainly on issues such as the raw materials and their contribution in the glazing process, the criteria for determining the faience glazing methods, the necessary quantity of alkalis for a successful cementation glazing, and, particularly, the glazing mechanism.     

Low‐temperature catalytic CO2 hydrogenation with geological quantities of ruthenium: a possible abiotic CH4 source in chromitite‐rich serpentinized rocks

Metal‐catalysed CO₂ hydrogenation is considered a source of methane in serpentinized (hydrated) igneous rocks and a fundamental abiotic process germane to the origin of life. Iron, nickel, chromium and cobalt are the catalysts typically employed in hydrothermal simulation experiments to obtain methane at temperatures >200°C. However, land‐based present‐day serpentinization and abiotic gas apparently develop below 100°C, down to approximately 40–50°C. Here, we document considerable methane production in thirteen CO₂ hydrogenation experiments performed in a closed dry system, from 20 to 90°C and atmospheric pressure, over 0.9–122 days, using concentrations of non‐pretreated ruthenium equivalent to those occurring in chromitites in ophiolites or igneous complexes (from 0.4 to 76 mg of Ru, equivalent to the amount occurring approximately in 0.4–760 kg of chromitite). Methane production increased with time and temperature, reaching approximately 87 mg CH₄ per gram of Ru after 30 days (2.9 mgCH₄/g_ru/day) at 90°C. At room temperature, CH₄ production rate was approximately three orders of magnitude lower (0.003 mgCH₄/g_ru/day). We report the first stable carbon and hydrogen isotope ratios of abiotic CH₄ generated below 100°C. Using initial δ¹³C_CO2 of ‐40‰, we obtained room temperature δ¹³C_CH4 values as ¹³C depleted as ?142‰. With time and temperature, the C‐isotope separation between CO₂ and CH₄ decreased significantly and the final δ¹³C_CH4 values approached that of initial δ¹³C_CO2. The presence of minor amounts of C₂‐C₆ hydrocarbons is consistent with observations in natural settings. Comparative experiments at the same temperatures with iron and nichel catalysts did not generate CH₄. Ru‐enriched chromitites could potentially generate methane at low temperatures on Earth and on other planets.     

The meteorological jet stream as a source of medium scale gravity waves in the thermosphere: an experimental study

Results are reported of a co-ordinated experimental study of medium scale gravity waves involving use of a multistatic incoherent scatter system together with two networks of polarimeters monitoring transmissions from a geostationary satellite during a six-day period in July 1974. The latter observations give access to the horizontal propagation parameters of the waves while the former technique yields information on the vertical structure of both waves and the ambient atmosphere. A reverse ray tracing analysis, through the atmosphere, for each gravity wave is described and its validity and accuracy discussed in detail. For the majority of the waves the reverse group path can be followed down to tropopause level and comparison with meteorological data has shown that many of the possible source regions of the observed waves appear to lie in proximity to the jet stream, with some evidence to suggest a preference for the polar side of the jet. Other wave sources are found to be close to regions of convectively unstable cold polar air. Wave energetics are discussed together with possible generation mechanisms, the latter in the form of non-linear interaction of shear flow instabilities in the jet stream and penetrative convection.     

The extent of farm desertion in central Sweden during the late medieval agrarian crisis: landscape as a source

The effects of medieval agrarian crisis on settlement and population were considered in a major interdisciplinary research project in Scandinavia during the 1960s and 1970s. Within this project, there were significant differences in methods used to calculate the extent of farm desertion between historians in the participating countries. The reliance on written source material within the Swedish team reflected the dominant approach amongst historians who made less use of map and landscape evidence than others. In this renewed investigation of the magnitude of farm desertion in the Late Middle Ages, focussing on the province of Jämtland in central Sweden, field survey of the physical landscape and some three thousand historical maps are used as evidence, alongside conventional written sources, such as official letters and taxation documents. The results indicate that the extent of farm desertion in medieval Sweden has been underestimated because Swedish scholars generally eschewed the use of the retrogressive method, which their Norwegian counterparts had been using since the 1940s. There is therefore good reason to reassess the desertion rates of medieval farms in other parts of Sweden as well, using traditional geographical source materials together with the documentary sources usually favoured by historians This may also hold for other parts of Europe as well. The rate of desertion is discussed in a wider context of settlement contraction and expansion in central and peripheral areas of Sweden, including the long drawn-out process of reclamation of the deserted farms (ödesbölen).     

The environment as a life support system: the case of Biosphere 2

This paper studies an attempt to replicate the Earth’s biosphere in the second half of the twentieth century with the aim of preserving and refashioning the environment as a self‐reproducing ecological system. Ecosystems dynamics framed the planet Earth as a closed system and directed scientific attention to questions of global environmental management. The image of the Earth as a spacecraft and operable in a similar way supported ideas of placing the environment in a laboratory setting. Using the case of Biosphere 2, launched in the Arizona desert in 1983, this paper studies the images of nature and environment contained in this quest to create an ecosystem and human habitat as good as, or superior to nature on Earth (known in this context as Biosphere 1). The second biosphere was designed as ‘a prototype for a space colony’ that would eventually enable its deteriorating predecessor, the Earthly biosphere, to reproduce and allow human settler societies to migrate to other planets. The paper draws on the cultural history of the ship in Western culture and on ships and spaceships as archetypes of autarkic enclosures set apart from nature. It argues that Biosphere 2 as an example of a technologically controlled endosphere advanced an understanding of the environment as a ‘life support system’ that emphasized not completeness but systems integrity, and was based on principles of functionality and replaceability. The paper will explore how notions of biospheric life support shaped demands on the natural and social environments in Biosphere 2 and Biosphere 1.     

Carn Alw as a source of the rhyolitic component of the Stonehenge bluestones: a critical re-appraisal of the petrographical account of H.H. Thomas

The source of the Stonehenge bluestones was first determined in the early 1920s by H.H. Thomas who was an officer with the Geological Survey of England and Wales. He determined that the so-called ‘spotted dolerites’ could be petrographically matched to a small number of outcrops in the Mynydd Preseli district in south-west Wales. The bluestones, however, comprise a number of additional lithologies, including rhyolite and ‘calcareous ash’, as well as various sandstones. Thomas was convinced that the volcanic lithologies in the bluestone assemblage were all sourced from a small area at the eastern end of the Mynydd Preseli, with the rhyolites originating from the prominent outcrop known as Carn Alw. Recently, provenancing of these rhyolites to Carn Alw has been questioned on the evidence of whole-rock geochemistry. This raised concerns over the original petrographical attribution. Accordingly a re-investigation was undertaken of the rhyolite petrography by re-examining the original specimens used by Thomas. Three of the original four thin sections studied by Thomas were re-examined, along with a newly made thin section from the fourth of Thomas' rock samples as the original thin section could not be located. The new petrographical evidence demonstrates convincingly that the two pairs of thin sections from the Preseli and Stonehenge as examined by Thomas do not match despite his contention and argues strongly that Carn Alw is not the source of the Stonehenge rhyolites which Thomas described. This reinforces the geochemical evidence presented recently and supports the contention that Craig Rhos-y-felin, to the north of Mynydd Preseli, is an important source of rhyolitic debris in the Stonehenge Landscape. Nevertheless, there remain uncertainties over the provenance of other Stonehenge rhyolites (and dacites), including four of the orthostats themselves.     

King Stephen,the English church,and a female mystic: Christina of Markyate's Vita as a neglected source for the council of Winchester (August 1139) and its aftermath

One of the central reasons for the disintegration of royal authority (sometimes called ‘the Anarchy’) during the reign of King Stephen of England is generally thought to have been his troubled relationship with the English church. The king was summoned to appear before the legate in England, Henry of Blois, bishop of Winchester (who was also Stephen's brother), at a church council called for Winchester on 29 August 1139, in order to show cause for his conduct in arresting several prominent bishops and in confiscating their property. Several major chroniclers discuss the events leading up to and occurring at the council of Winchester, especially William of Malmesbury in his Historia novella and the anonymous Gesta Stephani. The versions of events contained in these sources are not entirely consistent. The present paper examines yet another recounting of the events of the council, seldom appreciated by historians of twelfth-century England, presented in the Vita of Christina of Markyate (c.1096/98–c.1155/66), composed by an anonymous monk of St Albans between 1140 and 1146. Christina was close to the abbot of St Albans, Geoffrey de Gorham, who was probably the patron of the Vita and who quite likely attended the Winchester council and apparently became involved in its aftermath. These events are recorded in some detail in the Vita, presenting us with a vivid recounting of the council and the immediate consequences thereof. The narrative of the Vita contains a somewhat different picture of the personalities and occurrences surrounding the Winchester council than we encounter in the chronicles. The current essay compares the Vita to the standard accounts. We argue that the Vita may be the earliest and possibly most reliable source for the events of the council. Moreover, if we privilege the report of the Vita, the council becomes an especially significant moment in the breakdown of relations between Stephen and the English church.     

King Stephen,the English church,and a female mystic: Christina of Markyate's Vita as a neglected source for the council of Winchester (August 1139) and its aftermath

One of the central reasons for the disintegration of royal authority (sometimes called ‘the Anarchy’) during the reign of King Stephen of England is generally thought to have been his troubled relationship with the English church. The king was summoned to appear before the legate in England, Henry of Blois, bishop of Winchester (who was also Stephen's brother), at a church council called for Winchester on 29 August 1139, in order to show cause for his conduct in arresting several prominent bishops and in confiscating their property. Several major chroniclers discuss the events leading up to and occurring at the council of Winchester, especially William of Malmesbury in his Historia novella and the anonymous Gesta Stephani. The versions of events contained in these sources are not entirely consistent. The present paper examines yet another recounting of the events of the council, seldom appreciated by historians of twelfth-century England, presented in the Vita of Christina of Markyate (c.1096/98–c.1155/66), composed by an anonymous monk of St Albans between 1140 and 1146. Christina was close to the abbot of St Albans, Geoffrey de Gorham, who was probably the patron of the Vita and who quite likely attended the Winchester council and apparently became involved in its aftermath. These events are recorded in some detail in the Vita, presenting us with a vivid recounting of the council and the immediate consequences thereof. The narrative of the Vita contains a somewhat different picture of the personalities and occurrences surrounding the Winchester council than we encounter in the chronicles. The current essay compares the Vita to the standard accounts. We argue that the Vita may be the earliest and possibly most reliable source for the events of the council. Moreover, if we privilege the report of the Vita, the council becomes an especially significant moment in the breakdown of relations between Stephen and the English church.     

Seismic refraction tomography surveys as a method for voids detection: an application to the archaeological park of Cava Ispica,Sicily, Italy

Geophysical surveys are commonly used in areas where the presence of ancient civilizations is historically documented. These investigations are able to detect through indirect methods the presence of bodies or structures in the subsoil measuring the variations of some physical parameters, obtaining information about archaeological remains without causing harm to them.

In the present study, we investigated the presence of anthropogenic buried cavities partially filled with rubble material, in an area located in the northern part of Cava Ispica, one of the most important archaeological sites located in south-eastern Sicily. The results of seismic refraction prospections, processed with tomographic methods, are presented and discussed. The entire valley contains prehistoric burial sites, Christian catacombs and residential units of various kinds. Despite the numerous searches made over past years, much still remains to be discovered.

The seismic refraction tomographic data, analyzed in 3D, revealed the presence of low velocity values (<400 m/s) areas that, considering the lithotypes locally present and the features of other archaeological structures discovered during previous surveys, can be ascribed to the presence of possible cavities. The obtained results show how such geophysical inspections represent an important preliminary tool for archaeological surveys.     

Testing child-woman ratios and the own-children method on the 1900 Sweden census: Examples of indirect fertility estimates by socioeconomic status in a historical population

Focusing on the Swedish census of 1900, the child-woman ratio and own-children method have been applied to assess socioeconomic differences in fertility. These indirect estimates of fertility have been compared to the vital statistics at the national level to assess their reliability. This comparison demonstrated that the estimated results suffered from few errors. Even if these indirect estimates of fertility could be affected by possible socioeconomic differences in mortality, the tests show that at least in the Swedish case, the impact of mortality on the indirect measures is limited. As infant mortality differences by socioeconomic status are relatively small, indirect fertility estimates are mainly affected by differences in reproductive behavior.     

Dendrochronological dating of wooden artifacts by measuring the tree rings using magnifying glass and photography-assisted method: an example of a Dutch panel painting

Dendrochronology, an analysis of tree rings, is a commonly used method for dating wooden structures in archaeological remains and historical objects. Fascinating subjects of examination are the historical oil paintings on oak panels. Here, we applied a tree ring analysis on three boards of a Dutch painting from the Sinebrychoff Art Museum (Helsinki). Tree rings were measured using the conventional lens-assisted method, in addition to the photography-based approach, where the widths of the rings were determined from digital enlargements of the photos. These two methods produced comparable tree ring series. The lens- and photography-based records of the measured panel exhibited higher agreement with each other than the conventional, lens-based, record against the different master chronologies. Dendrochronological cross-dating against the master chronology showed that the rings of the panel represent the period ad 1413–1620. Cross-dating was attained by comparing the tree ring series of the panel painting with the previously published chronologies obtained from timber transported from the historical ports of the Eastern Baltic Sea to Western Europe. Photography appears as a promising method to be used for dendrochronological investigations of archaeological and historical objects, alongside the conventional methods. We note that the importance of using photographs of tree ring cross sections was highlighted already in the 1930s. In the digital era, the photographic approach shows obvious benefits for archival purposes and remeasuring the rings, with additional future prospects of image processing and analyses.     

"That Food of the Memory which Gives the Clue to Profitable Research": Oral history as a source for local, regional, and family history in the nineteenth and early twentieth century

Numerous local, regional and family historians in the nineteenthand early twentieth century collected oral narrations and conductedinterviews as a form to document information that otherwisemight have never been preserved. Family historians, in particular,not only practiced interviewing relatives for family histories,but also encouraged the practice in how-to-do manuals amongtheir peers. While advocating the practice, family historiansalso reflected about the value of "traditionary evidence" collectedthrough interviews and other means. These reflections by familyhistorians mirrored the discussions about the value of traditionsand memories as historical sources among several professionalhistorians at the time. These reflections were shaped by a modernizedunderstanding of tradition, which combined a reverential approachto the authoritarian element of tradition with a critical approachquestioning the validity of tradition. In this context, oralhistory was both a tool to negotiate the value of traditionand a mirror to the contemporary understanding of tradition.     

歌唱与家屋的建构——广西西部德靖一带壮族民间"吟诗"((n)am2 θei1)暖屋的观念与实践

被精英阶层视为文学艺术的东西,对于生活在乡土社会的人们而言,往往首先作为一种生活方式在社会生活中发生着实际的作用.因此,在探寻这类作品形式和内涵的意义时,需要将其置于广阔的背景中,注意其与总体的文化系统的整合和关联.