NOVEMBER 2010

MAGAZINE OF THE ROYAL AUSTRALIAN CHEMICAL INSTITUTE INC.

Ancient culture at the Australian SynchrotronWomen and the research cultureTravels with a titrator

Most of us will admit to having been buried in ourwork at some time. But if you were a servant to

the ancient Egyptian nobility, circa 3000 BCE, youmight literally have been buried alive with your masteror mistress when they died. The aim was to ensure thatpharaohs and other members of the nobility would nothave to do any menial work in the afterlife, somethingmany of us still aspire to.

History is unclear on how long the practice lasted,but it may have been phased out as a matter ofcommonsense. After all, why waste a perfectly goodservant? Much better to paint their likenesses on thetomb walls, or build a servant to take care of you.

The small statuettes found in tombs dating fromlater periods of ancient Egypt circa 2000–340 BCEultimately performed this function, working as personalslaves or undertaking manual labour on behalf of thedeceased. Called shabti, the figurines were initiallyintended to provide a home for the dead person’s ka orlife-force.

Made from clay, limestone, wood or Egyptian faience(sometimes known as synthetic turquoise), shabtis wereoften equipped with farming or fishing implements andexquisitely glazed or painted. At their peak, shabtis werefound in all but the poorest of graves. One tomb isrecorded as having one for every day of the year – with

20 NOVEMBER 2010

Something old, something newAncient culture at the Australian Synchrotron

NANCY MILLS

Ancient Egyptian artefacts have long been a subject of fascination. We can’t ask their

long!dead creators how they were made, but the Australian Synchrotron is the next

best thing, providing new insights into the chemistry of ancient cultural items.

Intended to serve aspersonal slaves in the

afterlife, these Egyptianshabti were made froma quartz!based ceramicmaterial called faience.

Image credit: Nancy Mills.

ten overseer shabtis to keep order. Not surprisingly, thelittle figurines now feature in distinguished museumcollections around the world.

Something borrowed, something blue

Several faience shabti recently found their way into thehands of La Trobe University archaeologist Mark Eccle-ston, on loan from the Ian Potter Museum of Art at theUniversity of Melbourne. Mark is using the AustralianSynchrotron as part of an ongoing investigation into theproduction of Egyptian faience, a quartz-based ceramicmaterial with a vitrified blue-green surface glaze. Calledtjehenet (‘that which is brilliant or scintillating’) by theEgyptians (Nicholson 2009), the material was dubbed‘faience’ by early European travellers, who saw similari-ties with a type of late-mediaeval, tin-glazed potteryfrom Faenza in northern Italy.

Described as ‘the first high-tech ceramic’ (Nicholson2009), faience is essentially a reconstituted stone thatwas independently discovered in Egypt, the Near East,the Aegean and some parts of Europe. The main ingre-dients are silica (SiO2), lime (CaO) and an alkali such asnatron, a naturally occurring salt consisting of sodiumcarbonate and sodium bicarbonate that was used in themummification process. During firing, the lime andsoda in the faience mixture react with the silica to forma small amount of glass that binds the silica grains.

The faience mixture was moulded or shaped byhand, but the material was thixotropic (subject tochanges in viscosity) and details were often lost from the final product. Adding natron or plant ash as alkalibinders made the faience easier to work with. Thecolour of the faience varied according to the ingredientsand the methods used to work the material.

Mark’s interest in faience is related to his ongoinginvestigation of the use of metals in ancient Egyptduring the New Kingdom (from around 1500 to 1100 BCE), primarily copper and copper alloys such asbronze. The characteristic blue-green colours of faiencewere created by adding copper, but whether this wasadded to the mix as copper metal or an alloy such asbronze, or derived from oxides or other minerals is notknown. Manganese, possibly as the oxide, was used toadd black details such as hieroglyphs.

An important trade item, Egyptian faience wasmainly used for small objects such as amulets, rings and

beads. It was often mass-produced in factories, but someitems were apparently made in large domestic breadovens. Mark believes this may mean that women made abigger contribution to local industries such as faienceand metals than previously thought.

The metal-working and faience industries weresometimes located together, and Mark would like toknow how the production facilities were organised andwhat raw materials they used. As well as illuminatingour knowledge of faience production, identifying theraw materials would provide insights into the micro-economic behaviour of individuals and groups involvedin making and trading faience, raw materials trading anddistribution in the wider economy and the organisationof trade activities within wider city life. Knowing whichforms of copper and other raw materials were used inthe production process would tell us something abouthow these materials might have been acquired by thepeople who made the faience. For example, were the rawmaterials readily obtained or was state input needed foraccess to ‘special’ or ‘controlled’ materials?

Mark demonstrated the production of faience in areplica 1300 BCE wood-fired bread oven (Eccleston2008) during the 2008 excavation season at Amarna, anarchaeological site on the east bank of the Nile Riverabout 300 kilometres south of Cairo. Occupied for justtwo or three decades, Amarna is a unique time capsuleof life at around 1350 BCE.

He made the faience from a mixture of powderedquartz, ball clay, gum Arabic, soda ash, crushed lime-

21NOVEMBER 2010

Egyptian faience made in 2008 to an ancient recipe. Image credit: Mark Eccleston.

22 NOVEMBER 2010

stone and copper oxide. The faience items were placedon a bed of quartz pebbles and pottery sherds, and theoven was held above 800°C for an hour before beingallowed to cool naturally. The firing process weakenedthe quartz pebbles so much that they could easily becrushed to a fine powder and used as raw material forfurther batches of faience.

In collaboration with La Trobe University physicistPeter Kappen, Mark is now putting a series of blue-green faience-glazed objects to the test at synchrotronsin Australia and Germany.

Mark and Peter are using the X-ray absorption spec-troscopy (XAS) and powder diffraction beamlines atthe Australian Synchrotron with additional XASstudies at HASYLAB (the Hamburg synchrotron radia-tion laboratory) in Germany. They have also used theAustralian facility’s macromolecular crystallographybeamline to examine faience beads.

The XAS work helped identify the chemical form ofthe copper present in the glaze, while the powderdiffraction work showed that the material did notcontain any copper minerals. This raises interestingquestions about the change in structure of the copperwithin the glaze as it is fired, and highlights the need forcombining the results of various techniques to under-stand how faience may have been made. Further experi-ments are planned using laboratory-made faienceprepared according to known recipes in order to create adatabase that will enable researchers to ‘reverse engineer’the production process and determine the raw materialsused in antiquity.

Overall, the synchrotron results have improved thecollaborators’ knowledge of the structure of faience andenabled them to ask more-probing questions. The nextphase of the research will involve much closer examina-tion of the atomic near-range order and structure ofcopper within the faience matrix and of the possibilitythat the copper is distributed through the amorphousglassy phase of the glaze as nanoparticles. Mark expectsthat the results will help him identify raw materialslikely to have been used to colour the objects. The pairhas also demonstrated the value of synchrotrons forexamining whole objects, which is a very useful resultfor further work with museum collections.

Old ...

Less than a century aftercelebrated Australianartist Arthur Streetonpainted his own portraitat the height of his career,a new collaborationbetween art and sciencehas revealed details of ahidden Streeton self-portrait, also painted inthe early 1920s. DavidThurrowgood from theNational Gallery ofVictoria and DeborahLau from CSIRO used the Australian Synchrotron’s X-ray fluorescence microprobe (XFM) beamline toexamine the Streeton work, with permission from theartist’s grandson.

Synchrotron techniques are ideal for examiningworks of art because they are non-destructive and canrapidly provide detailed chemical information. TheXFM beamline can scan an entire canvas section bysection, analysing the chemical composition of differentcomponents and ‘fingerprinting’ the elements present indifferent pigments.

The collaborative investigation will encourageincreased use of synchrotron techniques for studyingartists’ materials and methods, assisting restorationwork, and potentially providing new evidence in caseswhere an artist’s identity is unclear.

Other Australian Synchrotron techniques used tostudy works of art include infrared microspectroscopyand X-ray powder diffraction.

... older ...

The infrared microscopy beamline at the AustralianSynchrotron is being used to help clarify the chemistryof historic and cultural materials from the 19th and20th centuries as well as much older materials fromAboriginal rock art and Mayan paints and plasters.

Alana Treasure from the University of Canberra andthe Australian War Memorial is studying the mecha-nisms by which corrosive iron gall inks degrade parch-ment supports from the 19th and 20th centuries. Thework complements international studies of ink degrada-

tion on paper (cellulose) supports. Knowledge of thesemechanisms is assisting the development of conserva-tion treatments to preserve documents and artworksthreatened by iron gall ink corrosion degradation incollections worldwide, including the National Archivesof Australia. The degradation process is followed bylooking at changes in the amide group in the parchmentcollagen.

Researchers from the University of Melbourne andthe Centre for Cultural Materials Conservation inMelbourne have used the infrared microscopy beamlineto examine paint cross-sections from a late 19th centurycommercial building, the Provincial Hotel in theMelbourne suburb of Fitzroy (Sloggett et al. 2010). Thebeamline’s five-micrometre spatial resolution enabledthe researchers to successfully analyse major and minorcomponents in the highly stratified paint cross-sections,revealing details of all changes to the decorative facadeof the building and reflecting the history of paint tech-nology from the 1880s to the 1950s. The group is alsoinvolved in an international collaborative study of thestability and ageing of 20th century paintings fromSouth East Asia and Northern Australia.

Researchers from Queensland University of Tech-nology recently brought paint and stucco samples froma Classic Maya site in Honduras to the infraredmicroscopy beamline. They are keen to gain a betterunderstanding of plaster and painting techniques usedin the Maya culture, particularly the chemistry of somepigments unique to Maya buildings. The group alsobrought samples from an Aboriginal rock art site in

north Queensland, where the art is typically less than 20 micrometres thick, with the aim of better under-standing the materials used by these people.

… oldest

Solar wind and stardust samples collected by NASAspacecraft, including the Genesis mission, are probablythe oldest samples brought to the Australian Synchro-tron so far. Back on an earthly plane, the oldest terres-trial (okay, the oldest marine) object brought to theAustralian Synchrotron is a 380-million-year-old fossil.

The fossil in question is a small bone from a placo-derm, an extinct armoured fish that was the first verte-brate animal to possess jaws, pelvic and pectoral fins.The Kimberley region of Western Australia is renownedfor its exceptionally well-preserved fossils. In early 2009,another West Australian placoderm fossil causedconsiderable scientific excitement when an internationalresearch team realised it was evidence for sexual repro-duction (aka internal fertilisation) – and for live birthsaround 200 million years earlier than had previouslybeen believed (Long et al. 2008). A fossil from NewSouth Wales, also a placoderm, has provided some ofthe first definite fossil evidence of a forerunner to thehuman eye (Young 2008).

The current keeper of the placoderm fossil broughtto the Australian Synchrotron is Catherine Boisvertfrom the Australian Regenerative Medicine Institute, apalaeontologist interested in all aspects of morpholog-ical evolution. Working with Kate Trinajstic fromCurtin University of Technology, Catherine is lookingat pelvic evolution in the first jawed vertebrates.Catherine brought the fossil to the Australian Synchro-tron so that imaging and medical beamline staff couldtest the capabilities of the computed tomographycomponent of the beamline. She plans to come backagain when the beamline’s phase contrast capabilitiesare available later this year.

The synchrotron enabled the internal structure ofthe bone to be seen without destroying the specimen.This is essential when dealing with rare fossil materials.Synchrotron computed tomography provides higher-resolution images than laboratory-based X-ray sources.

23NOVEMBER 2010

The fossil remains of an extinct armoured fish are extendingour knowledge of evolution. Image credit: John Long (Long1995).

Continued page 27

pyrotechnics; barium is used for green. As early as1863 Lamy reported on the toxicity of thallium(Lamy 1863).

Spectrum analysis was a very hot topic in the early1860s. In March 1861, Roscoe presented a lecture tothe Royal Institution of Great Britain entitled ‘OnBunsen and Kirchoff ’s spectrum observations’ (Roscoe1861). In 1862, to the same Institution, Roscoe gave acourse of three lectures on the use of spectrumanalysis (Roscoe 1862). In 1861, William A. Miller,Professor of Chemistry at King’s College London,presented a lecture ‘The new method of spectrumanalysis’ to the British Association for the Advance-ment of Science (Miller 1861). About six monthslater, Miller presented a similar lecture before thePharmaceutical Society of Great Britain (Miller1862). William Allen Miller (1817–70) (Clerke andMcConnell 2004) was an older brother of FrancisBowyer Miller (1828–87) (Martin 2005), inventor ofthe chlorine method (Miller process) for refining goldthat was featured in Part 5 of this series (August issue,pp. 12–16).

Early Australian interest in spectrum

analysis

Given the tyranny of distance, and the youth of theAustralian Colonies, it is interesting that spectrumanalysis became the subject of three Australian papersin the 1860s – two were read before the Royal Societyof Tasmania, and one was presented to the Philosoph-ical Society of Queensland. These papers, and themen responsible for them, will be dealt with in Part 7of this series.David J. Collins FRACI CChem <david.collins@sci.monash.edu.au> is an

Honorary Senior Research Fellow, School of Chemistry, Monash Univer!

sity, and Honorary Senior Fellow, School of Philosophy, Anthropology

and Social Enquiry, University of Melbourne.

* This chronicle is based on early entries in an electronic database,

‘Chemistry in Australia pre!1900’, recently completed by the author and

containing 1098 records. It highlights some of the earliest reports of

chemical studies communicated to scientific societies, and/or published

in scientific journals by chemists working in Australia. A list of publica!

tions referred to in this chronicle can be found at

www.raci.org.au/chemaust and further information on the database

can be obtained from the author.

† The complete 1860–1869 bibliography is available at

www.raci.org/chemaust, together with the additional references

(shown here in italics).

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Phase-contrast X-ray imaging allows much greatercontrast from weakly absorbing materials such as softtissue than is possible by conventional methods.

Catherine is keen to continue collaborating withbeamline staff to develop soft tissue computed tomog-raphy scanning methods for sharks and other fish togain high resolution 3D anatomical data.

REFERENCES

Eccleston M. 2008, Egyptian Archaeology 32, 33–5.Long J.A. 1995, The rise of fishes: 500 million years of evolution. University

of New South Wales Press, Sydney; also John Hopkins University Press,Baltimore, USA. 1995. 230pp. ISBN 0868400785.

Long J.A., Trinajstic K.M., Young G.C., Senden T. 2008, Nature 453, 651–3.Nicholson P.T. 2009, Faience technology. In Willeke Wendrich (ed.), UCLA ency-

clopedia of egyptology, Los Angeles.<http://escholarship.org/uc/item/9cs9x41z>

Sloggett R., Kyi C., Tse N., Tobin M.J., Puskar L., Best S.P. 2010, Vibrational Spec-troscopy 53(1), 77–82.

Young G.C. 2008, Biology Letters 23(4), 110–14.

As a young teenager, Nancy Mills <nancy.mills@synchrotron.org.au>

wanted to be an archaeologist. She eventually chose chemistry, but man!

aged to combine the two when she worked with materials conservation

staff and maritime archaeologists at the WA Museum.

Continued from page 23

Coming up in December

• A natural offshore asset and its challenges for chemistry

• Convicts, chemistry and spectroscopes

• Climate change: short answers to big questions

• RACI 2010 award winners