British Museum blog

A closer look at what the Chiseldon cauldrons are made of

High magnification image of one of the cauldrons

Quanyu Wang, scientist, British Museum

I am a scientist specialising in metalworking technology, particularly in relation to non-precious metals such as iron and copper-alloys. The scientific examination and analysis of the Chiseldon Iron-Age cauldrons is a key aspect of the investigative process as a whole and is crucial in supporting our understanding of them.

For the Chiseldon cauldrons I have been examining the microstructure of the metal under very high magnification in order to see its composition, deduce how it was worked and explore manufacturing techniques. Some of the questions I will be trying to answer include: ‘How were the cauldrons made?’, ‘Were different components from an individual vessel made in the same workshop?’, ‘Were the same parts, such as the iron handles for different vessels, made from the same metal stocks’ and, perhaps the most important question of all; ‘Were the cauldrons made especially for burial or collected together for a particular occasion?’

Taking a sample from one of the cauldrons

Taking a sample from one of the cauldrons

Finding appropriate samples to test can be extremely difficult as the metal, particularly the iron, is extremely corroded and very fragile. The sampling process is made additionally complicated by attempting to sample a potential area that is as discrete as possible to make sure that we do not endanger the structural integrity of the artefact but will yield the best results. This is not a decision that is taken lightly and sample positions are chosen in consultation with curators and conservators. In order to reveal the structure of the metal the samples are mounted in resin, their cross-section polished, and then examined using metallographic microscopy up to x1000 magnification and a scanning electron microscope equipped with energy dispersive X-ray spectrometry (SEM-EDX) that allows us to examine them up to 300,000 times its actual size.

We have been able to deduce that the iron handles from both the cauldrons studied so far were probably formed by repeatedly hammering an iron bar while it was rotated. Additionally, iron used for the same parts of different cauldrons showed differences in microstructure and slag (impurity) inclusions, and was therefore from different stocks of metal, suggesting that these cauldrons were probably collected together rather than being made at the same time specifically for burial.

A high magnification scanning electron microscope (SEM) image of a copper alloy sample from one of the cauldrons. Darker horizontal lines were caused by many cycles of working and heating

A high magnification scanning electron microscope (SEM) image of a copper alloy sample from one of the cauldrons. Darker horizontal lines were caused by many cycles of working and heating

The copper-alloy is likely to have been subjected to many cycles of working and annealing (heating) to reduce the sheet metal to its final thickness (and shape). Significantly, there are differences in the content of sulphide within the copper alloy from one of the cauldrons, which suggest that the metal of the bowl and that of the band were probably refined to different levels or were from different sources.

Some of the results we have achieved so far are intriguing and much more revealing than expected given the condition of the material. Further analysis of the remaining cauldrons will not only provide further details of how the metal was processed and how the cauldrons were made but will help us build up a more complete picture of the deposit as a whole.

The Chiseldon cauldrons research project is supported by the Leverhulme Trust

Find out more about this research project

If you would like to leave a comment click on the title

Filed under: Archaeology, Chiseldon cauldrons, Conservation, Research

One Response - Comments are closed.

  1. John Winterburn says:

    Some great images , thanks for posting these.

    Like

Enter your email address to follow this blog and receive notifications of new posts by email.

Join 16,361 other followers

Categories

Follow @britishmuseum on Twitter

British Museum on Instagram

Edward Burne-Jones was born #onthisday in 1833. This watercolour from his ‘Flower Book’ is titled ‘White Garden’. This was a name for Atriplex hortensis, a small garden plant that has edible leaves. In this painting Burne-Jones has created an imaginary ‘white garden’, populated with lilies that are being picked by two white-clad angelic figures. Like other figures in his works, they appear dressed in classically inspired white robes, with their blonde hair tied back.
#EdwardBurneJones #BurneJones #PreRaphaelite #flowers In this second watercolour from the ‘Flower Book’ of Pre-Raphaelite artist Edward Burne-Jones, we can see the goddess Venus walking through the night’s sky with doves. This painting is titled ‘Rose of heaven’ – a name given to the plant campion, a small pink flower. Burne-Jones took inspiration from the name of the flower and its connotations, rather than what the flower actually looks like. The depiction of Venus seems to be heavily influenced by Botticelli’s ‘Birth of Venus’, with flowing blonde hair and a dynamic pose.
#EdwardBurneJones #BurneJones #PreRaphaelite #flowers To mark the birthday of Pre-Raphaelite artist Edward Burne-Jones (1833–1898) this week, we’re featuring paintings from his ‘Flower Book’ – a sketchbook full of watercolours and drawings that contained fantasy artworks inspired by the names of flowers. This painting is titled ‘Love in a tangle’ – a name sometimes used for the climbing plant clematis. The scene suggests the story of Ariadne, who gave Greek hero Theseus a ball of golden thread to unwind as he wandered through the labyrinth in search of the minotaur (a mythological creature – half-man and half-bull). Here she waits anxiously for her lover to follow the thread back out of the maze. The clematis and its maze of tangled foliage inspired Burne-Jones to represent this story from ancient Greek mythology in his Flower Book.
#EdwardBurneJones #BurneJones #PreRaphaelite #flowers #mythology Here’s a #regram from @mrapachekat. Doesn’t this lion look majestic? The Museum’s Montague Place entrance is just as grand as the more-visited Main entrance on Great Russell Street. This part of the Museum contains the King Edward VII galleries, and the foundation stone was laid by the King in 1907. This side of the building was designed in the Roman style rather than the Greek Revival of Great Russell Street. It features numerous imperial references, including the coat of arms above the door, and sculptures of lions’ heads and crowns. The architect Sir John James Burnet was knighted for his work designing these galleries, and the building was opened by King George V and Queen Mary in 1914 (Edward VII had died in 1910). #regram #repost #architecture #BritishMuseum #lion Another brilliant photo of the Museum’s Main entrance on Great Russell Street – this time by @violenceor. The perspective gives a good sense of the huge scale of the columns. The Museum has two rows of columns at the main entrance, with each being around 14 metres tall and 1.5 metres wide. Designer Sir Robert Smirke used 44 columns along the front elevation. This design of putting columns in front of an entrance is called a ‘portico’, and was used extensively in ancient Greek and Roman buildings. #regram #repost #architecture #neoclassical #BritishMuseum The Museum looks spectacular with a blue sky overhead – especially in this great shot by @whatrajwants. You can see the beautiful gold flashes shining in the sun. This triangular area above the columns is called a ‘pediment’, and was a common feature in ancient Greek architecture. The copying of classical designs was fashionable during the late 18th and early 19th centuries, and was known as the Greek Revival. The sculptures in the pediment were designed in 1847 by Sir Richard Westmacott and installed in 1851. The pediment originally had a bright blue background, with the statues painted white. #regram #repost #architecture #neoclassical #sculpture #gold #BritishMuseum
Follow

Get every new post delivered to your Inbox.

Join 16,361 other followers

%d bloggers like this: