THE EMIGRATION OF PREALPINE LAKE MASTERS: A STUDY OF A 17TH‐CENTURY MANTELPIECE ATTRIBUTED TO THE CARLONE FAMILY OF ROVIO (TICINO,SWITZERLAND)*

This work illustrates the possible connections between the phenomenon of the seasonal emigration of lake masters and the production of artistic artefacts. Within the ambit of these dynamics, a stucco mantelpiece was taken into consideration. Nothing was known about the object: neither its origin, nor the artist who produced it, nor the period of execution. Historical, stylistic and formal analyses of the materials and of the technique with which the work was executed allow us to verify that the mantelpiece was produced using the stucco technique in the 17th century, in Rovio (southern Switzerland, Ticino), and that it comes from one of the exponents of the Carlone workshop, whose representatives were important in the tradition of itinerant artistic workers. Due to their good technical and professional specialization, the Carlone workshop served both public and private buyers. Tommaso Carlone is the principal representative artist of the Carlone workshop; it is certain that his workshop produced the stucco mantelpiece. The migrations of the artists were seasonal and they maintained a close bond with their country of origin. When they returned to the country of origin, they produced works of great artistic value, of which the mantelpiece represents a splendid example. Through the employment of conventional analytical techniques (optical and electron microscopy, infrared spectroscopy and porosity measurements), it has been possible to study the technique with which the work was executed, the materials used and the decay. The mantelpiece was produced using the stucco technique by means of a body layer (slaked lime and silicate and carbonate aggregates) and a marmorino finishing layer (slaked lime and pointed calcite crystals). Above this layer, whose thickness varies in relation to the executed result, there is a thin lime plaster whitewash, pigmented with the dispersion of yellow ochre particles; chromatic alterations are an oxalate patina caused by firm adhesion to the marmorino layer, due to the denaturation of the proteic substances employed. The final treatment was made with beeswax, which increased the marmoreal effect. Several additional layers of lime plaster whitewash have also been applied over the centuries. The figurative central square of the plastic decoration was made using red ochre.     

Lime Burning in Clamp Kilns in Scotland's Western Central Belt: Primitive Industry or Simple but Perfectly Adequate Technology?

Lime is a fundamental component in many industrial, agricultural and chemical processes, and is itself produced by an industrial process, namely, the heating in kilns (calcining, or more colloquially ‘burning’) of calcium carbonate rock or other carbonate material. Research and literature on lime burning in Scotland, based largely on lime production in Scotland's eastern Central Belt, are dominated by the view that lime burning in draw kilns is the paradigm for Scottish lime production. Other parts of Scotland, however, largely or completely ignored, draw kilns in favour of simpler clamp kilns, even in major industrial sites of lime production. This paper reports our map- and field-based surveys in Scotland's western Central Belt, which clearly point to the enduring importance and almost exclusive use of clamp kilns in that area's historical lime-burning industry.     

Traditional Burnt-Lime Production at Mayapán,Mexico

Abstract

Lime was widely utilized throughout ancient Mesoamerica. Drawing on the expertise of traditional Maya lime producers from a small local community, we address the energetics, material inputs, and archaeological signature of burnt-lime production in the Northern Yucatan Peninsula of Mexico. When compared with the estimated lime usage at the Maya site of Mayapan, the data collected from experimental lime burning suggest that traditional lime production was reasonably labor intensive and used large, albeit sustainable, quantities of raw materials, especially wood. Lime manufacture was an important component of ancient Mesoamerican economic life, especially in urban settings where it may have been a full time occupation for some, at least during certain parts of the year. This analysis allows us to predict what the remains of lime burning sites should look like and where they are most likely to be encountered archaeologically.     

Characterization of ancient building lime mortars of Anhui province,China: A multi-analytical approach

The characterization of lime mortars has become of primary importance in order to obtain information about the raw ingredients and building technology of ancient masonry structures. Five different samples from Anhui province, China, representing two types of lime mortar-based materials: joint mortars between the bricks of the city wall and lime mortar sealing a tomb coffin, were collected for analysis. Archaeological information about the samples was reported and studies into the microtextural features and mineralogical compositions of those mortars were performed via a multi-analytical approach. The joint lime mortars between the bricks of city walls, including Mingzhongdu city wall, Mingzhongdu Xihua gate foundation, Zhengyangguan city wall and She county city wall, were found to be aerial lime mortars. The lime mortar from Nanling Tieguai Song dynasty tomb was analysed and found to be a pozzolanic mortar consisting of lime, clay, sand and cocciopesto-like materials. The analytical results serve as a critical reference for the maintenance and restoration of ancient city walls in Anhui province, and as a starting point for searching for ancient Chinese pozzolanic mortars and technology for making those mortars.     

The production technology of Egyptian blue and green frits from second millennium BC Egypt and Mesopotamia

The microstructures and chemical compositions of some 55 Egyptian blue and green frit samples from New Kingdom Egypt and 15th century BC Mesopotamia are determined using analytical scanning electron microscopy, the main focus being on frit cakes, powder residues, and frit vessel and bead fragments from one of the “factory areas” at Amarna in Middle Egypt. Replicate Egyptian blue frits produced in the laboratory are similarly investigated. Comparison of the microstructures of the ancient and replicate samples suggest that frit cakes are the primary product, and that these were ground to produce the powder, and then moulded to shape and refired to produce the vessels and beads. Egyptian blue and green frits are shown to be distinct pigments, the pigment produced depending on the relative proportions of copper oxide and lime in the mixtures. The bulk and glass phase compositions are used to try to infer the different sources of the quartz, lime, copper and alkali flux used in the production of frits from Egypt and Mesopotamia. An estimate is made of the scale of production of Egyptian blue frit in New Kingdom Egypt.     

Characterization of lime carbonates in plasters from Teotihuacan,Mexico: preliminary results of cathodoluminescence and carbon isotope analyses

This study characterizes the degree of calcination of lime in lime plaster samples from Teotihuacan, the capital of a regional state in prehispanic Central Mexico. Lime plaster production consists of multiple steps, from the firing of raw materials to the mixing of lime and aggregate and the final application. While previous studies have focused on the compositional variability, specifically the recipe of lime plasters and mortars, the characterization of lime itself has not been sufficiently addressed. In this study, cathodoluminescence analysis coupled with petrographic and image analyses were employed to examine the degree of calcination of lime. The results of cathodoluminescence petrography were further examined through stable carbon isotope and ¹⁴C measurements. It appeared that the results of cathodoluminescence analysis are consistent with those of other analytical methods and that there are diachronic changes in the degree of calcination of lime among lime plaster samples. This implies changes in the organization of lime production, specifically the consistency in the control of firing temperature.     

Site conservation during excavation: treatment of masonry,wall plaster and floor mosaic remains of a Byzantine church in Petra,Jordan

Abstract

The conservation treatments carried out between June 1992 and August 1993 on the architectural remains of a Byzantine basilica in Petra, Jordan, during and immediately after the excavation are described. The treatments completed during excavation included: stabilization and consolidation of certain sections of the basilica's sandstone ashlar masonry; cleaning and consolidation of the unpainted lime wall plaster decorating the basilica interior; cleaning and consolidation in situ of the extensive remains of a figurative mosaic pavement in the two side aisles, and the fragmentary remains of the opus sectile pavement in the central aisle. The consolidation treatments included injection grouting using hydraulic mortar mixes produced in Italy, and mortar repairs using slaked lime and hydraulic lime. The existence of the mosaic required preventive conservation measures during the excavation, such as the construction of a temporary shelter over the site during the winter, the use of temporary protective facings over damaged areas of the mosaic, as well as the temporary backfilling of the mosaic with soil over a layer of geotextile in order to protect the mosaic between the initial phase of conservation work and the construction of a permanent shelter for the site in the near future. The importance of having a conservator present on site during the critical phase of excavation, when all materials are most susceptible to damage, is emphasized. The Petra Church Project will hopefully serve as a model for future excavations in that it employed two conservators from the beginning of the excavation: one for small finds, the other responsible for the site and the architectural remains removed from the site during the excavation.     

Qadhat—a comparative study of ancient and new lime mortar from the Marib province/Yemen

Qadhat is the name for a lime mortar in Southern Arabia. Its usage has a long tradition. This work describes physical and mineralogical properties of ancient, historical and new samples, which seem to have been produced the same way. XRD, thin sections and SEM analyses show the similarity of the material. It consists of aggregates of volcanic material that are rich in volcanic glass and lime as binder. The production process includes several hours of crushing the material, which produces fine-grained splinters of aggregates in the binder matrix and gives the mortar a high stability. A weathering test with sodium sulphate on different samples confirms that the stability of this mortar is the result of the production process.     

Analytical Investigations of Traditional Masonry Mortars from Ancient City Walls Built during Ming and Qing Dynasties in China

With the development of China’s economy, the protection and conservation of ancient buildings were put on the agenda. However, the current understandings on Chinese traditional mortars are limited and rarely reported in the literature. In this article, the authors investigate seven ancient city wall sites built during the Ming and Qing dynasties (1368–1841 AD) in situ, and subsequently the laboratory analysis were carried out on the collected mortar samples. The characterizations of mortar samples were performed using digital microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), simultaneous thermal analysis (TG-DSC), as well as wet chemical analysis. The analytical results show that pure lime mortar was widely used in construction during the Ming and Qing dynasties, and it was also a common practice adding sticky rice soup into slaked lime to form sticky-rice lime mortar during preparations. This organic-inorganic composite material could effectively improve mechanical strength of the lime mortar. Moreover, it was first found that the sticky-rice lime mortar sample from Kaifeng ancient city wall contained very fine quartz aggregates, with an approximate binder/aggregate ratio of 1:1. The appearance of this type of mortar probably indicates a great development of Chinese traditional mortars during the mid-19th century.     

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.     

Colum Giles & Mike Williams (eds), Ditherington Mill and the Industrial Revolution. Swindon: Historic England, 2015. 172 pp., 118 illus. £50. isbn 978-1-84802-118-1

Abstract

As part of the Glamorgan-Gwent Archaeological Trust's survey of the Gower peninsula, a study of disused lime kilns on the peninsula's limestone belt was initiated in 1984. At its commencement the project appeared to be straightforward, but it soon expanded into an extensive study as both calculation and documentary research revealed previously unexpected aspects. An intensive map search doubled the anticipated number of kiln sites and revealed the fact that the early nineteenth century kilns were located in the portion of the limestone belt where the greatest amount of Dolomite was present, thus suggesting that the early lime burners preferred Dolomite to other limestones. Then by analysing the lime burning process and using contemporary data, the process of lime kiln development during the nineteenth century became apparent, also the possible background to statements in contemporary accounts. In addition, analytical studies also revealed why the use of Dolomite for lime production could have been an attractive alternative to using other forms of limestone. With the completion of the historical research phase, the Friends of the Trust have set up a group to visit each known site and compile the formal Sites and Monuments Record. It is anticipated that, in due course, some kilns will be excavated or renovated as appropriate. In order to maintain knowledge of kiln site locations now that reference to them will no longer be present on as maps, a list of them is being published in the 1988 issue of the journal Gower together with an article placing them in their local context.     

Glass beads and pendants from Meroitic and Nobadian Lower Nubia,Sudan: Chemical compositional analysis using laser ablation‐inductively coupled plasma‐mass spectrometry

This paper presents a detailed elemental analysis of 64 glass beads and pendants dated to the Meroitic period (first–third centuries ad ) and the Nobadian period (fourth–sixth centuries) from burial sites in the Lower Nubian Nile Valley region. Laser ablation‐inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS) was used to determine the chemical composition of the glass and to gain knowledge about its origin. Four main glass types were identified: low‐alumina soda‐lime glass, high‐alumina glass, plant‐ash soda‐lime glass, and mixed‐alkali glass. Mineral soda‐lime glass (m‐Na‐Ca) of East Mediterranean/Egyptian provenance is dominant within the low‐alumina glass group from Meroitic and Nobadian periods. Mineral soda high‐alumina glass (m‐Na‐Al) appeared in the Nobadian bead assemblages, and the m‐Na‐Al 1 subtype was produced in Sri Lanka/South India. An initial insight into the origin of the glass beads in Nubia from the first to sixth centuries is described, indicating the first evidence for the presence of Asian objects in Nubia. The data obtained for the bead trade in North‐east Africa in this study has allowed a new light to be shed on the westward flow of Asian glass during a time of intensive maritime trade contacts with the wider Indian Ocean world.     

Design and evaluation of hydraulic lime grouts for the reattachment of lime plasters on earthen walls

Abstract

A laboratory and field testing programme for the formulation and evaluation of hydraulic grouts was developed for the reattachment of lime plasters on earthen (adobe) walls. Formulations utilizing kaolin, hydraulic lime, ceramic microspheres, and fine silica sand, with and without the addition of an acrylic emulsion, were prepared and evaluated in a three-stage testing programme. Standard tests were employed to measure injectability, viscosity, set time, shrinkage, weight, splitting/tensile strength, water vapour transmission rate, and adhesive bond strength. Grout microstructure was comparatively examined using scanning electron microscopy. Of the 18 grout formulations tested, only one mixture composed of (parts by weight) 1 part microspheres, 1 part sand, 2 parts hydraulic lime, 10% part acrylic emulsion was found to meet all the essential performance criteria established.     

我国传统镁质石灰初步研究

对我国从明代到民国的建筑灰浆的化学成分、矿物成分等分析发现,部分砌筑及抹灰灰浆为镁质石灰,MgO含量达到5%~26%。特别是取自河北、北京等地长城的传统石灰样品全部为镁质石灰。镁质石灰与钙质石灰比较,具有强度高、吸水率低的特点,从而具有更佳的抗冻融性能。此外,镁质石灰收缩低、易于施工。镁质石灰煅烧需要的温度低于钙质石灰,能耗低。鉴于传统镁质石灰在中国的研究尚为空白,建议系统地开展镁质石灰研究,研究内容包括原材料类型及分布、煅烧温度、消解方式、配比优化等。同时宜研究镁质石灰在严重大气污染下的耐久性及镁质石灰相关建筑遗产的保护修复技术等。     

THE BLUE ENAMELS IN THE BAROQUE DECORATIONS OF THE CHURCHES OF PALERMO,SICILY: FE2+‐COLOURED GLASSES FROM LIME KILNS*

Deep blue glasses coloured by octahedral Fe²⁺ cations are often reported as textbook examples of blue pigmentation. However, despite the possibility of laboratory synthesis under reducing conditions, to date there are no well‐reported occurrences of their production and use in the past. A thorough historical, ethnographic, mineralogical, and chemico‐physical investigation of the ‘smaltini di calcara’ from several baroque churches in Palermo, Sicily, has revealed that the blue enamels widely used for altar decorations in the 17th and 18th centuries are actually a unique case of ancient blue glasses pigmented by divalent iron cations in distorted octahedral coordination. This mixed‐alkali glass was accidentally produced under severely reducing conditions in the local kilns during production of lime.     

An archaeometric study of the bulk and surface weathering characteristics of Early Medieval (5th–7th century) glass from the Po valley,northern Italy

Compositional and structural characterisation was carried out on Early Medieval (5th–7th century) fragments of glass goblets excavated from the archaeological sites of Monte Barro, Brescia and Monselice (northern Italy) with the aim of identifying raw materials, glass-working techniques, and surface weathering characteristics. Optical analyses and X-ray spectrometry were used for bulk, and X-ray photoelectron spectroscopy and scanning and transmission electron microscopy for surfaces. The samples of each area were produced using siliceous–lime sands, with natron as flux. The differences observed in chemical composition allow to subdivide the samples from Monte Barro and Brescia from those of Monselice, the latter generally show higher silicon, calcium and aluminium and lower sodium contents than the others. By plotting reduced base glass compositions in soda–lime silica phase diagrams, melting temperatures varying from 900 °C for Monte Barro and Brescia samples to 1000 °C and more for those from Monselice were estimated. Differing Fe₂O₃, Sb₂O₅and MnO₂contents are related to the different colours of the samples, Monselice samples being blue–green and Monte Barro and Brescia samples green and yellow–green. The chemical differences may be interpreted as related to different provenance and/or glass-working techniques. Surfaces are depleted in alkaline and alkaline-earth elements due to weathering process. Alteration lamellae show a nanostructure, similar to that of opal.     

Lime Powder Production in the Maya Puuc Region (A.D. 600–950): An Experimental Pit-Kiln

Powdered lime was one of the most significant materials in the daily lives of the Prehispanic Maya, yet archaeologists have uncovered relatively little evidence of production methods or locales prior to the Spanish conquest. The recent identification of a series of pit-kilns dating to the Late and Terminal Classic periods (ca. a.d. 650–950) in and around the site of Kiuic in the Puuc region of the northern lowlands of the Yucatán Peninsula provides the opportunity to investigate a sub-regional Prehispanic lime production technology. Here we present the preliminary excavation results of nine pit-kilns and then describe the experimental reconstruction and firing of a lime pit-kiln. The results indicate that the pit-kilns are more fuel-efficient than the aboveground pyres used during the post-conquest period. This in turn suggests that Prehispanic inhabitants of the Puuc managed their consumption of natural resources for producing lime during a period of sociopolitical, demographic, and environmental stresses.     

PROVENANCE OF THE LIMESTONE USED IN TEOTIHUACAN (MEXICO): A METHODOLOGICAL APPROACH*

This work shows the preliminary results of an international project for the interdisciplinary study of the limestone used in the plasters of the ancient city of Teotihuacan. The limestone provenance was studied using a new approach based on the chemical analysis of the lime lumps that were selected because they represent the composition of the original limestone rock. The results show that the applied methodology was successful and that the limestone used to produce the lime employed to make the floor of the main courtyard at Teopancazco (Teotihuacan), comes from the region near Tula (Hidalgo).     

The Chronology of Insiza Cluster Khami‐Phase Sites in South‐Western Zimbabwe: Compositional Insights from pXRF and Raman Analysis of Excavated Exotic Glass Finds

Fourteen glass beads and one glass fragment from Khami‐period (ad 1400–1830) sites of Danamombe, Naletale, Gomoremhiko, Nharire and Zinjanja, in Zimbabwe, were analysed by pXRF and Raman spectroscopy with the intention of correlating the results with associated radiocarbon dates. The results show that Zinjanja and an earlier part of the Danamombe stratigraphic context had Khami Indo‐Pacific beads (15th–17th centuries) corresponding with Torwa occupational layers. Other European beads and one bottle fragment [high‐lime, low‐alkali (HLLA) glass] dating from the 16th to the 19th centuries were confined to the top stratigraphic layers of Danamombe and Naletale, which coincide with the later Rozvi occupational layers. Gomoremhiko had one Mapungubwe–Zimbabwe bead series (13th–15th centuries), which suggests that it was probably earlier than the other sites. All European beads are made of soda–lime plant‐ash glass with high alumina, which makes them comparable with glass produced through the Mediterranean traditions in Southern Europe.