RESEARCH REPORT: MAGNETIC INVESTIGATIONS AND THE AGE OF A MEDIEVAL KILN AT KUNGAHÄLLA (SOUTH‐WEST SWEDEN)*

The results from a magnetic survey and archaeomagnetic investigation of a medieval brick kiln at Kungahälla in Bohuslän (south‐west Sweden) are reported. Detailed magnetic total field and magnetic gradient measurements over known traces of the kiln showed marked local magnetic anomalies of up to 200 nT, revealing the rectangular shape of the kiln remains. Palaeomagnetic investigations of the remanent magnetization of 12 bricks from the kiln floor gave precise definitions of both the direction of the archaeomagnetic field [(D_m, I_m) = (66.7°, 8.8°), k = 655, α₉₅= 1.7°] and the palaeointensity [B_m= 69.0 ± 3.6 µT]. An archaeomagnetic date is obtained by comparing the direction of the archaeomagnetic field found in the kiln with a geocentral dipole‐transformation of the British master‐curve for secular variation. Of two possible archaeomagnetic dates (ad 1280 ± 50 or ad 1480 ± 50), the ad 1280 ± 50 age is in good accordance with the C‐14 ages and archaeological dates as well as with direct historical evidence, whereas a c. 100 years younger TL date appears to be too young.     

MEAN SHIFT: A NON‐PARAMETRIC ALGORITHM FOR THE SEGMENTATION OF ANOMALIES IN GEOPHYSICAL IMAGES OBTAINED FROM MAGNETIC PROSPECTION DATA

This paper studies the applicability of the Mean Shift algorithm as support in interpreting geophysical images produced, on this occasion, from magnetic prospection data. The data obtained from a magnetic survey carried out in Gilena (Seville province, Spain) by the La Rábida Archaeophysics Group will be used for the research. Its applicability is illustrated by comparing, on the one hand, some reduction‐to‐pole algorithms and on the other, the (well‐known) k‐means algorithm. Finally, the paper shows the results obtained by applying the Mean Shift algorithm as an alternative method to ‘unsupervised clustering’ of anomalies that appear in images obtained from geophysical data, in which the a priori knowledge of the number of classes is difficult or impossible.     

Combined archaeomagnetic and thermoluminescence study of a brick kiln excavated at Fontanetto Po (Vercelli,Northern Italy)

A combined archaeomagnetic and thermoluminescence study was carried out as part of a rescue archaeological excavation on a kiln discovered during the installation of methane gas pipelines beneath a rice field, along the southern border of Fontanetto Po village (Vercelli province, Italy). A total of 23 independent brick samples have been collected, oriented in situ with an inclinometer; the use of magnetic and sun compass was not possible due to the existence of metallic tubes beneath the kiln and a plastic cover above it. Standard archaeomagnetic procedures have been used for the determination of the archaeomagnetic inclination and absolute geomagnetic intensity. Stepwise thermal demagnetization shows a very stable characteristic remanent magnetization and the calculated mean inclination of the 23 samples is I = 65.3° with α₉₅ = 2.4° and k = 156. Archaeointensity experiments have been performed using the classical Thellier method as modified by Coe, with regular partial thermoremanent magnetization (pTRM) checks. The cooling rate and remanence anisotropy effects upon thermoremanent magnetization (TRM) have been investigated in all the specimens. A total of 19 archaeointensity determinations (at specimen level) that correspond to linear NRM–TRM plots were used for the calculation of the site mean archaeointensity that is 46.4 ± 2.9 μT. Archaeomagnetic dating results show two possible dating intervals for the last 1000 years, calculated at 95% confidence interval: a first one from 1511 to 1614 AD, and a second one from 1768 to 1872 AD. Thermoluminescence (TL) study has been also performed on two brick samples from the kiln's internal wall, using conventional laboratory procedures. According to the thermoluminescence results the kiln's last usage lies between 1796 and 1914 AD. This age is in good agreement with the second dating interval obtained by the archaeomagnetic analysis. The combined archaeomagnetic and thermoluminescence results suggest that the last firing of the kiln could have occurred between the end of the 18th century and the beginning of 20th century.     

A scientific study of Choson white ware: early porcelain from a royal kiln at Kwangju Usanni

Scientific study of kiln site no. 9 at Usanni, one of the earliest royal Kwangju kiln complexes in operation (from the early 15th to the early 16th century), shows that the technological expertise used to produce white ware was inherited from the celadon technology of the Koryo dynasty. The body material, of low Al₂O₃ and high SiO₂ content, is based on porcelain stone. Such a material, with almost no titanium and a low level of iron, was a rediscovery of the white ware material used earlier at the Sori kiln from the 9th century through to the 11th century. Ash continued to be one of the major ingredients of the glaze, and wares were fired in much the same way as the Koryo celadon, in kilns constructed of mud and rocks and in two steps. The Confucian philosophy and aesthetic of frugality and simplicity adopted from the Ming dynasty onwards by the new government acted as the catalyst for the successful ascent of the new technology.     

A study of the glazing techniques and provenances of Tang sancai glazes using elemental and lead isotope analyses

This study discusses the elemental compositions and lead isotope ratios of Tang sancai glazes unearthed from the Huangpu kiln, Huangye kiln and two Tang sancai tomb sites. The various glazes feature distinct lead isotope ratios and trace element characteristics, which can be interpreted as evidence for the use of different lead ore deposits and siliceous raw materials in the glazes. This is a strong indication that lead isotopes combined with trace element analysis could be used as a viable approach for identifying the provenance of Tang sancai of unknown origin by linking them to kiln sites, This provenance technique could be significant in the interpretation of ancient ceramic trade and communication patterns. In this study, the provenance of several Tang sancai glazes of uncertain origin were determined using this method: some Tang sancai wares unearthed in Xi'an City were produced in the kiln near Luoyang City and then traded to Xi'an City, providing an idea of ancient Tang sancai ceramic trade routes.     

Matéo Maximoff's La Septième fille: A Roma Testimony of Internment and Assimilation

Set in the internment camp at Lannemezan where the author and his family spent two years, Matéo Maximoff's La Septième fille gives a voice to a minority group that has suffered from negative stereotypes since its arrival in France in the Middle Ages. In that work, Maximoff, the first authentic Roma novelist, blends folklore and oral tradition with historical fact, chronicling the conditions in the camp at Lannemezan even as he spins a supernatural tale worthy of the most gifted of conteurs. Informed by historical sources and ethnographic studies, this article suggests that La Septième fille may be read as a metaphor for the internment of the Roma by the Vichy regime and the policies aimed at ‘socialising’ and forcing them to become sedentary, policies that began during the Third Republic and that continued well into the twentieth century. La Septième fille is one of the rare literary works (along with Didier Daeninckx's La Route du Rom, 2003) to treat the little-known Vichy initiative of interning Roma—the majority of whom were French citizens—in 31 camps around France.     

A STUDY ON LATE MEDIEVAL TRANSPARENT‐GLAZED POTTERY AND ARCHAIC MAJOLICA FROM ORVIETO (CENTRAL ITALY)*

Nineteen samples of medieval transparent‐glazed pottery and archaic majolica from Orvieto (central Italy) were studied. They were classified by archaeological criterion as follows: five transparent‐glazed fragments with green and brown decorations (first half of the 13th century), eight green transparent‐glazed fragments (13th century) and six tin‐glazed fragments with green and brown decorations (second half of the 13th century). SEM–EDX, XRD (the Rietveld method) and XRF were used to characterize the chemical and mineralogical compositions both of the bodies and the coatings. In all of the samples, the paste is Ca‐rich with CaO contents as high as 13–20 wt%. The mineralogical composition is compatible with a firing temperature of about 950°C, which is the typical temperature reached in a wood kiln. No difference was observed between the bodies of transparent‐ and tin‐glazed pottery. In the case of transparent glazes, the burial conditions lead to heavy weathering of the samples. However, on the basis of the analyses carried out in non‐weathered areas, the typical composition is PbO 55–65 wt%, SiO₂31–35 wt%. In tin glazes, the tin is scattered on the mass of the glaze as SnO₂crystals with a concentration of 7–14 wt%. Concerning the decorations, it is established that the green colour is due to the presence of copper, while manganese is responsible for the brown colour. These pigments, which represent the typical colours of ‘archaic majolica’, are spread through the glaze homogeneously, apart from one case in which there is clear evidence of manganese oxide crystals.     

Roman traces in Germania magna: New thermoluminescence and pIRIR290 data from a lime kiln at Bergisch Gladbach,Germany

The applicability of a post‐infrared infrared stimulated luminescence (pIRIR₂₉₀) protocol and two different thermoluminescence (TL) protocols—a single aliquot regeneration (SAR) and a multiple aliquot additive dose (MAAD)—was tested on six polymineral fine‐grain (4–11 μm) samples extracted from the wall remains of a Roman lime kiln and a Roman roof tile. These remains had been excavated close to Bergisch Gladbach, which was at that time part of Germania magna. For the pIRIR₂₉₀ measurements, no dependence of D_e on first‐stimulation temperature was detectable, and the standard first stimulation temperature at 50°C was adopted. Fading tests and dose‐recovery tests were made for all samples. Background subtracted glow curves were recorded up to 480°C for TL after a preheat of 220°C for 120 s. A‐values were determined for all TL and pIRIR measurements. The results for all three protocols were fairly consistent, and TL and pIRIR₂₉₀ protocols are shown to be suitable to estimate reliable equivalent doses for the fired kiln walls. The resulting ages are in agreement with the expected time range—Roman Iron Age—and with independent age control provided by radiocarbon ages of animal bones and charcoal from the firing chamber.     

Raw or Pre-Fired: Kiln Construction at Sawankhalok,North Central Thailand,as a Guide to Ceramic History

Sawankhalok, located in north central Thailand, was an early stoneware ceramic production site where the first kilns were dug cave-like into the natural ground, a method used in China for thousands of years. After a century or so, kilns at Sawankhalok began to be constructed of brick. It is suggested that if the bricks were pre-fired then an external influence may have been responsible. To the contrary, if raw unfired clay was used in the construction of the kilns the evolution was more likely a consequence of conceptual continuity.With the aid of chemical and mineralogical analyses it is shown that the kiln bricks were unfired at the time of kiln construction thereby suggesting that traditional conservatism, apparent in many aspects of the industry, caused processes to remain unaltered in the absence of a persuasive reason for change. These conclusions reflect on the degree of indigenous technology and artistic development associated with Sawankhalok ceramics as opposed to external influence.     

The Conte-en-vers: Expanding Stith Thompson's X-File of Obscene Motifs

The conte-en-vers is a narrative dealing with bawdy subjects presented in verse form and with a certain elegance of expression that contrasts markedly with its licentious content. La Fontaine's Contes, provide material through which to explore bawdy stories that were circulating during the seventeenth century. Furthermore, La Fontaine's followers in the eighteenth and nineteenth centuries afford a rich source from which to glean information about erotic folktales current in France during that period. The conte-en-vers genre is of special significance to folklorists because the authors incorporated current folklore motifs into their tales, making of them an important, though neglected, repository of folklore during three centuries. The conte-en-vers provides a corpus which facilitates the task of filling in Stith Thompson's blank category of obscene motifs, X700-749 “Humor Concerning Sex.”     

A Clay Fireback at Hitchin,Hertforshire

Abstract

Two discoveries of pottery kilns at Brill, Buckinghamshire, during construction work in 1974 and 1975 are described. One, a fairly complete kiln, is dated to the early seventeenth century and two others to the latter half of that century. The last working Brill kiln of 19th-century date was also re-discovered. The longevity of the industry is briefly discussed and the products of the post-medieval phase described.     

A 17th-century Kiln Site at Woolwich

Abstract

This report describes the results of the excavation of two adjacent kilns at Woolwich, one producing earthenware and one producing stoneware. Both date from the third quarter of the 17th century, though evidence suggests that the stoneware kiln is the earlier of the two. The report also includes a discussion of an earlier feature, a clay-lined pit, as well as several features associated with the three main features. The earthenware kiln had twin stoke holes and produced domestic pottery. The stoneware kiln had a single stoke hole and produced Bellarmine jugs with other stoneware vessels, and is the only stoneware kiln of this period yet discovered in Britain.¹     

Identifying archaeological wood stack charcoal production sites using geophysical prospection: magnetic characteristics from a modern wood stack charcoal burn site

Charcoal making was a common process in the woodlands of Britain for many centuries. However, historic ‘wood stack’ production sites are difficult to identify. This paper tests the hypothesis that geophysical survey is an appropriate method for the discovery and identification of archaeological charcoal making sites. A traditional wood stack charcoal kiln was constructed in Low Staindale, Dalby Forest, near Pickering, North Yorkshire, to investigate the charcoaling process and the effect of low-temperature carbonisation on the magnetic properties of the soil underlying the kiln. The results from temperature monitoring (within and beneath the charcoal stack) throughout the charcoaling process, geophysical surveys across the charcoal kiln platform, and laboratory analysis of soil and ash samples, are presented. The degree to which the magnetic properties of the ground beneath the charcoal kiln had been enhanced as a consequence of this low-temperature process is discussed. Whilst some magnetic enhancement to the soil beneath the kiln platform was recorded, enhancement appears to be the result of contamination from the wood stack sealing material rather than the effect of heat transfer resulting from the charcoaling process. The results suggest that whilst historic wood stack charcoal production sites are likely to remain an enigmatic and under-reported feature in the archaeological landscape, geophysical prospection does have the potential for identification of these sites.     

Vietnamese (15th Century) Blue‐And‐White,Tam Thai and Lustre Porcelains/Stonewares: Glaze Composition and Decoration Techniques*

EDS, X‐ray fluorescence, Raman spectroscopy, thermal expansion–shrinkage measurement and scanning electron microscopy were applied to determine the elemental components, structural phases and glazing temperatures of the transparent glazes, blue underglaze and overglaze tam thai (including gold‐like lustre) decorations from the 15th‐century Vietnamese porcelains/stonewares found at the Chu Ðâu–My Xa kiln site and in the Cù Lao Chàm (Hôi An) cargo. The ancient technology for colouring the glazes is discussed. The various blue tones in the underglazed décor result from cobalt‐containing manganese ore, with the intentional addition of iron oxide. The overglaze copper‐green and the gold‐like lustre were obtained by dispersing copper in lead‐based glass. The red colour was made using hematite dispersed in lead‐rich flux.     

MAGNETIC SUSCEPTIBILITY VARIATIONS AT MONS CLAUDIANUS AND IN ROMAN COLUMNS: A METHOD OF PROVENANCING TO WITHIN A SINGLE QUARRY

Mons Claudianus in the Eastern Desert of Egypt was an important source of granodiorite for Roman columns. Computer contouring of 1119 magnetic susceptibility measurements at the quarry shows systematic variations, with low readings in the west of the quarry area and higher readings in the east. One hundred and seventy measurements on 62 columns of Mons Claudianus type in Rome and its environs were compared with the quarry readings, using a t-test based procedure. Some columns with distinctively low or high magnetic susceptibility could be provenanced very precisely to areas of about 700 × 700m within the 9km² of Mons Claudianus. Columns with susceptibility in the middle of the Mons Claudianus range could not be provenanced precisely. Results indicate early (first century AD) use of both west and east parts of Mons Claudianus, and contemporaneous use of several parts of the quarry, rather than systematic or sequential opening of the area. Columns found in third-century AD monuments, provenanced to the same parts of Mons Claudianus as earlier material, may indicate reuse of columns in some monuments. Magnetic susceptibility constitutes a portable and non-destructive method capable of provenancing not only to a quarry, but to specific areas within a single quarry.     

THE BEGINNINGS OF TIN-OPACIFICATION OF POTTERY GLAZES

A multidisciplinary programme of research on the glazed ceramics of the Islamic world has been focused on questions of their dating, provenance and technology. One particular question has been the development of tin-opacified glazes, and the nature of glaze opacification generally in the Islamic world. The findings of the various studies combine to indicate that tin was first used experimentally in Basra, Iraq, in the first half of the eighth century AD, apparently within the context of pre-Islamic opaque-glaze technology. Over the course of the next century, an opaque-glaze technology entirely reliant on tin oxide inclusions was developed in Iraq and Egypt and, subsequently, this technology spread to the rest of the Islamic world and also to Europe.     

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.     

GEOPHYSICAL INVESTIGATIONS OF LATE FOURCHE MALINE AND EARLY CADDO SETTLEMENT PATTERNING AT THE CRENSHAW SITE (3MI6)

Abstract

The Terán-Soule model provides a testable means to establish if the prehistoric settlement pattern of the Caddo in the Great Bend region of the Red River consists of vacant mound centers with associated dispersed farmsteads. To evaluate the model, a geophysical survey of the Crenshaw site (3MI6) mound center was conducted in off-mound areas to determine if structures were present there. The 3.2-ha survey identified over 100 geometric anomalies, of which more than 50 are possibly structures associated with either Late Fourche Maline or Early Caddo occupations. Several possible structures were found in linear rows, including an oval series of possible structures 90 × 85 m in diameter. Additional finds include large circular anomalies between 25 and 48 m in diameter, sometimes around possible structures, suggesting the presence of compound fences, as shown in the Terán map.     

NEUTRON ACTIVATION ANALYSIS OF ROMAN AFRICAN RED SLIP WARE KILNS

Roman African Red Slip ware (ARS) sherds from four ARS kiln sites in modern-day Tunisia (El Mahrine, El Ala, Oudna and Pheradi Maius) have been analysed using instrumental neutron activation analysis. Multivariate statistical methods (including cluster analysis and Manhattan City Block distances), with a dilution correction applied to the data, were used to interpret the concentration data. Reference groups for each of the four kiln sites were established. Both El Mahrine and Oudna were described by two dilution-related groups. These kiln groups were all shown to be compositionally distinct from each other and suitable for use in provenance studies.     

A GROUND RADAR SURVEY OF MEDIEVAL KILN SITES IN SUZU CITY,WESTERN JAPAN*

A ground-penetrating radar study of medieval kiln sites located near Suzu city, on the Noto peninsula, was conducted prior to excavation. Archaeological site plans estimated from time slices of the closely-spaced parallel radar profiles are compared with excavations and a proton magnetometer survey. The results indicate that non-destructive remote sensing with radar can help to determine effectively the presence and general structural features of intact kiln floors.