David Dungworth | Freelance Researcher (original) (raw)

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Papers by David Dungworth

Historical metallurgy, 2004

The archaeological evidence for medieval and post-medieval casting of large domestic vessels in E... more The archaeological evidence for medieval and post-medieval casting of large domestic vessels in England is reviewed. This consists of archaeological features, waste products and the finished artefacts. The distinctive nature of the alloy used (an antimony-rich leaded copper alloy) is discussed. It is argued that this alloy was a waste product from the extraction of silver from fahlerz ores.

... the 1960s to develop a method of dating igneous rocks (eg Moorbath and Bell 1965; see ... The... more ... the 1960s to develop a method of dating igneous rocks (eg Moorbath and Bell 1965; see ... The strontium isotope results for Silkstone provide an insight into the procurement of glassmaking raw materials ... F. Buckley, 2003, Old English Glass Houses, Society of Glass Technology. ...

Theoretical Roman Archaeology Journal

Oxford Handbooks Online, 2015

services.english-heritage.org.uk

SUMMARY Some 400 fragments of glass and glassy waste were recovered from the 14th-century glasswo... more SUMMARY Some 400 fragments of glass and glassy waste were recovered from the 14th-century glassworking site at Blunden's Wood. The assemblage included window and vessel glass, both of which were made at the site using a plant ash glass, rich in potassium, ...

Window glass is an essential component of most buildings but the transparency of much glass means... more Window glass is an essential component of most buildings but the transparency of much glass means it often goes unnoticed. Modern window glass is almost invisible but historic glass usually has a tint or colour and variations in surface texture and thickness, all of which distort a transmitted (and reflected) image. This distortion contributes to the overall aesthetic quality of a historic building. It is important that any architectural conservation decisions, such as the retention and/or replacement of window glass, proceed from a position of knowledge. The most important aspect of extant glazing is whether or not it is original. This paper explores the use of a chemical analysis technique to determine the age of historic glass.

Yorkshire Archaeological Journal

Numismatic Chronicle, 1996

Historical metallurgy, 2004

Theoretical Roman Archaeology Journal

Oxford Handbooks Online, 2015

services.english-heritage.org.uk

Yorkshire Archaeological Journal

Numismatic Chronicle, 1996

Portable XRF analysis has allowed the in situ analysis of over 500 panes of glass from Exeter Cat... more Portable XRF analysis has allowed the in situ analysis of over 500 panes of glass from Exeter Cathedral (windows EII, S3 and S4). The data is used to determine the periods of manufacture and the results are provided as colour coded illustrations which reveal those quarries and panels that are original and those which are later replacements. EII retains a great deal of medieval glass with some evidence for repairs by Peckitt in the 1760s. S3 retains some medieval glass but much of the glass was made after c1835 and was carefully produced to match the retained medieval glass. S4 uses recycled grisaille glass (probably from earlier windows than EII and S3) in medallions. The remaining plain diamond quarries in these windows are of varied date but indicate assembly in the 19th or 20th centuries.

William Champion’s Warmley brassworks, founded c. 1746, was the first integrated brass manufactur... more William Champion’s Warmley brassworks, founded c. 1746, was the first integrated brass manufacturing site, where all parts of the operation, from raw material processing to the finished product, were undertaken at one location. A review of archaeological interventions and recording undertaken between 1986 and 2011, together with a new scientific analysis of the technological residues, shows that despite development of the site over the last 160 years, substantial structural remains and industrial waste deposits related to the 18th century works are preserved below ground. In particular, the remains of Britain’s oldest surviving industrial zinc smelter have now been identified.

Glassworking in England from the 14th to the 20th Century, 2019

Annales of the 17th Congress of the International Association for the History of Glass 2006, Antwerp edited by K Janssens, P Degryse, P Cosyns, J Caen, L Van’t dack, 2009

Four samples of glass from a cupola or dome previously installed at the top of a stair case at No... more Four samples of glass from a cupola or dome previously installed at the top of a stair case at Northington Grange were examined. The glass is thick but curved; and smooth on one side but rough on the other side. The form of the glass suggests that it was cast and rolled then heated and bent over formers to achieve the desired shape. The glass is a soda-lime-silica glass made using a synthetic or industrial form of soda. This suggests that the glass would probably have been manufactured after c1835. A slightly earlier manufacture cannot be entirely ruled out as there is insufficient data on the nature of early plate glass. The presence of arsenic (presumably used as a refining agent) is most consistent with manufacture prior to c1870.

The chemical composition of a selection of window glass from Thornhill parish church was investig... more The chemical composition of a selection of window glass from Thornhill parish church was investigated in order to contribute to its conservation. The window glass includes examples of 15th-century stained/painted medieval window glass which has suffered from significant degrees of deterioration. The conservation treatment of these windows is being funded by English Heritage. Several different potential causes for the deterioration of the historic window have been advanced. The investigation included the chemical analysis of 55 panes of glass carried out in situ using a portable x-ray fluorescence (pXRF) spectrometer. In addition, five samples recovered from a 15th-century tomb were analysed using both pXRF and laboratory-based instruments. The glass includes both medieval forest glass and later high-lime low-alkali (HLLA) glass. The pXRF data could be used to identify the type of glass even where the result was affected by surface corrosion. The SEM-EDS data indicates that much of both the Forest glass and HLLA glass at Thornhill contains a very low molar proportion of SiO2 which renders it unstable and susceptible to significant deterioration.

This report presents the results of chemical analysis of historic window glass at Walmer Castle. ... more This report presents the results of chemical analysis of historic window glass at Walmer Castle. Previous research using laboratory-based techniques has demonstrated the relationship between the chemical composition of glass and its age. This report presents the first attempt to use a portable instrument to analyse historic window glass without damaging it. The benefits and limitations of a portable X-ray fluorescence (pXRF) spectrometer are explored through the analysis of samples of glass which had been analysed previously using laboratory-based techniques. The problems of analysing glass which also has a UV-absorbing film are also assessed through the analysis of 75 panes analysed from both inside and outside surfaces. This shows that the pXRF analysis of glass through a UV-absorbing film is not rewarding. The analysis of 661 of the Walmer Castle window panes is reported and the results are interpreted in relation to previous laboratory-based analyses and the architectural history of Walmer Castle. Four panes of glass are shown to have been made using seaweed ash and so can be dated to c1700–c1835. 235 panes of glass are shown to be made using synthetic soda prior to the introduction of mechanised drawing techniques, ie c1835–c1930. 222 panes of glass are shown to be made after the introduction of mechanised drawing, ie post-c1930. 43 panes of glass are shown to be made from an unusual potassium-calcium silicate glass. This glass includes the pink and purple glass in the dining room. There are few modern analyses of glass of this composition and historic sources provide little information. It is suggested that this glass was imported from Germany or Bohemia.

The investigation of historic window glass from the Music Room (originally constructed 1793–97) a... more The investigation of historic window glass from the Music Room (originally constructed 1793–97) at Kenwood House was undertaken using complimentary laboratory-based equipment and a portable XRF instrument to determine glass composition and type. The glass falls into two groups: a potassium-calcium-silicate glass and a sodium-calcium-silicate glass. The former is extremely rare in England but is paralleled at Walmer Castle, Kent. This glass was probably imported from Bohemia or Germany at considerable expense. It is not immediately apparent why such expensive glass was used in this context (blind windows) but the context may help to explain why this glass has survived for over two centuries.

The chemical analysis of fifteen fragments of window glass from Fort Cumberland was undertaken to... more The chemical analysis of fifteen fragments of window glass from Fort Cumberland was undertaken to identify the composition of glass used during the use of Casemate 54 and the repair of the Guardhouse (c 1940). The fragments of window glass from the Guardhouse all share the same composition and this compares well with reported values for glass manufactured in the middle of the 20th century. The fragments of window glass from Casemate 54 all share the same composition but this differs from reported 19th century glass. It is likely that all of the glass in casemate 54 was replaced in the later 20th century.

The chemical analysis of twelve fragments of window glass from Flint Lodge was undertaken in an a... more The chemical analysis of twelve fragments of window glass from Flint Lodge was undertaken in an attempt to identify the composition of the glass originally installed during its construction (1851). Eleven fragments have compositions which are virtually identical to each other and are similar to previously analysed 19th-century glass. These samples probably represent the glass installed in 1851. The remaining fragment has a composition which suggests that it is a later replacement.

The scientific examination and chemical analysis of window glass from the Royal Fusiliers Regimen... more The scientific examination and chemical analysis of window glass from the Royal Fusiliers Regimental Museum at the Tower of London was undertaken to determine the composition. The Museum was originally constructed in 1845 and it was hoped the analysis of the window glass would contribute to a better understanding of developments in 19th-century window glass production. The results show that of the samples which were assigned into four groups based on their chemical composition, one group can be considered to be typical of mid 19th century window glass and is tentatively considered to represent the original windows. The remaining groups are considered to be replacement glass, typical of post 1930s manufacture, probably post 1960s.

This report describes the scientific investigation of stained window glass from Beverley Minster,... more This report describes the scientific investigation of stained window glass from Beverley Minster, Yorkshire. The window glass comes from two panels in the west window produced by the John Hardman Company in 1859 and 1865. The glass has undergone conservation treatment at the York Glazier’s Trust to deal with several aspects of deterioration, including the degradation of the paint. The chemical analysis of the window glass shows that several different types of glass were used including soda-lime-silica and flint (potassium-lead-silicate) glass. In addition, some of the glass appears to have been made by mixing flint and soda glass (or perhaps just the raw materials for each glass type). Much of the glass displays a chemical complexity which does not seem to be strictly necessary but may reflect the extraordinary lengths that 19th-century glassmakers were forced to go to achieve glass for the Gothic revival. The range of metal oxides detected correlates closely with the colours of the finished glass and agrees with practice described in contemporary texts. The paint shows extensive degradation and in some cases the paint has completely corroded leaving only corrosion products. The chemical composition of the surviving paint is complex and offers no immediately obvious explanation why it has degraded.

The chemical analysis of thirteen samples of window glass from Horace Walpole’s house at Strawber... more The chemical analysis of thirteen samples of window glass from Horace Walpole’s house at Strawberry Hill, Twickenham was undertaken as part of a larger project investigating post-medieval window glass. While all other sites and assemblages investigated to date have been used to develop a model of chronological changes in window glass manufacturing practice and technology, the situation with this assemblage has been reversed. In this case the results of the chemical analysis have been used to suggest dates of manufacture and these dates have been compared with the prior dates suggested by architectural context. Four samples have compositions which are consistent with the suggested dates, five samples have compositions which suggest that the glass has been replaced at a later date, and four samples have unusual compositions which cannot currently be explained.

The scientific examination of fifteen samples of decorated window glass from Margam Castle provid... more The scientific examination of fifteen samples of decorated window glass from Margam Castle provides information on glass in use in the 1830s as well as the glass used for a repair in 1905. There are two types of colourless glass: the first made using seaweed ash and the second made using a synthetic soda. The contemporary use of both a seaweed glass and a synthetic soda glass is entirely consistent with the period. the seaweed glass was frequently stained yellow, orange or red using silver. the nature of staining has been investigated: Silver nano-particles imaged and elemental x-ray linescans obtained through the stained layers. In addition the black painted surfaces layers on the colourless glass have also been investigated. The coloured pot metals are all flint glasses with the addition of specific metals to provide the blue, green or purple colour.

The analysis of 55 fragments of flat glass from the Wentworth Conservatory was undertaken to dete... more The analysis of 55 fragments of flat glass from the Wentworth Conservatory was undertaken to determine the composition of the glass originally installed during its construction in 1877. A visual examination of the glass during collected suggested that much of the glass was later replacements of float glass from after 1960. The chemical analysis of the glass showed that the vast majority of it contains levels of magnesium that are consistent with manufacture after the introduction of automatic drawing techniques c1930. Four fragments (two of which are joining fragments) have very low levels of magnesia and are compositionally consistent with manufacture between c1830 and c1930. It is likely that this glass represents the glass originally installed at Wentworth in 1877.

The chemical analysis of thirteen fragments of window glass from Highland House was undertaken in... more The chemical analysis of thirteen fragments of window glass from Highland House was undertaken in an attempt to identify the composition of the glass originally installed during its construction in the 1880s. Two fragments have compositions which are similar to previously analysed late 19th-century glass. The remaining samples have compositions which suggest they are later replacements. The magnesium concentration of these later samples is considered and evidence for dividing them into an early group (1930–1960) with <3wt% MgO and a later group (1960+) with 3.5–4.1wt% MgO is discussed.

The chemical analysis of sixteen fragments of window glass from four separate houses in Welch Roa... more The chemical analysis of sixteen fragments of window glass from four separate houses in Welch Road was undertaken in an attempt to identify the composition of the glass originally installed during the construction (1894–95). Nine fragments (including at least one fragment from each property) share virtually identical compositions and so are interpreted as original glass. The original window glass is a soda-lime-silica glass and the composition is compared with available data for earlier 19th-century and 20th century window glass.

Refurbishment of Shaw House, Newbury provided the opportunity to analyse a range of window glass.... more Refurbishment of Shaw House, Newbury provided the opportunity to analyse a range of window glass. Over a hundred samples of window glass were collected, including samples from a window constructed at the end of the 17th century and blocked c1728 (Room B6) as well as windows installed between c1690 and c1720. The analysed window glass includes three major glass types: high-lime low-alkali, mixed alkali and soda-lime. The in situ samples from the turn of the 18th century demonstrate that the use of high-lime lowalkali glass was superseded by mixed alkali glass c1700. This mixed alkali glass was made using seaweed ash (kelp) as a flux and enabled the production of less strongly coloured window panes. The results of the analysis of the Shaw House window glass contributes to an on-going research programme into the manufacture of window glass from c1500 to c1950.

As part of a project to investigate changes in window glass manufacturing practice between 1500 a... more As part of a project to investigate changes in window glass manufacturing practice between 1500 and 1960, 187 samples of window glass from the site of the conservatory at Chatsworth were analysed to determine their chemical compositions. The conservatory was constructed between 1837 and 1840 under the supervision of Joseph Paxton who later designed the Crystal Palace for the Great Exhibition in 1851. The Chatsworth Conservatory was constructed using improved cylinder glass by Chance Brothers and Co of Birmingham. The forming technique had recently been introduced to Britain and also benefited from the use of synthetic alkalis (rather than more traditional alkalis based on plant ashes). The 187 samples have been assigned to four groups based on their chemical composition and Groups 3 and 4 have been tentatively identified as the glass originally installed between 1837 and 1840.

The analysis of window glass fragments recovered during archaeological excavations on the site of... more The analysis of window glass fragments recovered during archaeological excavations on the site of Basing House provide information on the chemical composition of glass produced between 1531, when the house was built, and its destruction in 1645. Three of the fragments of window glass are forest glasses which would have been produced before the late 16th century. The remaining samples are high-lime low-alkali (HLLA) glasses. If made in England, these would have been produced after the arrival of French glassmakers in England in 1567. If made on mainland Europe, however, these glasses could have been produced at the time that the house was constructed. A fragment of HLLA glass decorated with the Paulet badge must have been made before 1550 and so is certainly an import. Basing House appears to have gone into decline during the 17th century and it is unlikely that any of the analysed window glass was made after c.1600.

This report examines early eighteenth-century window glass recovered during the excavation of a s... more This report examines early eighteenth-century window glass recovered during the excavation of a seventeenth century glasshouse and eighteenth-century pottery. Two fragments of window glass are high-lime low alkali glass while ten are mixed alkali glass with high strontium contents indicating that they were manufactured using seaweed (kelp).