SUMMER 2013 VOLUME 5

WELCOME TO THE FIFTH

EDITION OF THE CLEPSYDRA

CHRONICLE ................... 1

THE MANCHESTER MU-

SEUM IS WORKING WITH TEAM

RHX ........................... 2

EXCITING NEWS FROM

OTHER RESEARCHERS WORK-

ING ON RHX DATING ....... 4 Clepsydra chronicle Welcome to the fifth edition of the

“Clepsydra Chronicle”. We are pleased

to report that our iButton temperature survey

is now underway. We would like to extend a

big thank you to all those who are involved in

collecting temperature data for us. Other excit-

ing news is that our new RHX web-pages are

finally live.

Please send any correspondence to rhxdating@gmail.com and for more details about rehydroxylation check out http://www.mace.manchester.ac.uk/our-research/research-themes/dating-fired-clay-ceramics/

As spring has sprung

here in the UK, the

cover image for this

issue is of a mural on

Newton Street, Man-

chester, only a short

walk from the univer-

sity campus in Man-

chester city centre.

Keeping with the Man-

chester theme, the

Manchester Museum is

heavily engaged in aca-

demic research at the

University of Manches-

ter and will be involved

in our current project,

see page 2. In other

news, we enjoyed a

visit from Professor

Scarlett, Michigan Tech-

nology University, see

page 3.

Image © Team RHX

The NERC project is a collaborative project. Team RHX is Dr Moira Wilson, University of Manchester, Dr Cathy

Batt, University of Bradford, Dr Andrea Hamilton, University of Edinburgh, Dr Margaret Carter and Dr Sarah-Jane

Clelland, University of Manchester. Newsletter content is produced by Dr Clelland.

We would like to announce

that we have had a journal

paper accepted by Ar-

chaeometry. The paper is

entitled Rehydroxylation of

fire-clay ceramics: factors

affecting early-stage mass

gain in dating experi-

ments”. This paper pre-

sents our current under-

standing of the observed

mass gain in ceramic mate-

rial both after “drying” at

105°C and after dehydroxy-

lating at 500°C. It explains

how we have identified the

three types of water dis-

cussed in the Summer 2012

edition of our newsletter

and the effect they have on

using mass gain data to

date ceramic material. Air

flow and constant condi-

tions of %RH and tempera-

ture are all important com-

ponents of the experimen-

tal methodology. Further

papers are planned to dis-

cuss these issues in more

depth.

The Manchester Museum is part of

The University of Manchester and the curators there contribute to the University’s research and higher learning agendas. The Museum is heavily involved in academic research and student teaching. As part of its role in supporting aca-demics in the wider university the Museum is considering sympathetically Team RHX’s request to test ceramics associated with one of the more significant items in Manchester’s archaeology collection, the Manchester Word Square, as Byran Sitch explains.

Moira Wilson meet-ing with Bryan Sitch, Deputy Head of Col-lections and Curator of Archaeology at the Manchester Mu-seum, They are ex-amining ceramic material recovered from the excavation which uncovered the Manchester Word Square.

The piece of pottery is inscribed with five five-letter words in Latin forming a palin-drome or a word square. Word Squares are also referred to as Sator or Rotas Squares because they contain the Latin words SATOR AREPO TENET OPERA ROTAS or ‘Arepo the Sower guides the plough with care’. It is not clear how this should be in-terpreted. The words are written in a square so they can be read top-to-bottom, left-to-right and right-to-left. These square are regarded by some as a cryptic markers for the outside of an early Christian house, because the letters resolve into a cross-shape reading PATERNOSTER (Our Father) both down and across. The letters that are left over, ‘A’ and ‘O’, are also significant because in the New Testament Jesus said, “I am the alpha and the omega, I am the beginning and the end”. Alpha and Omega

are the first and last letters respectively of the Greek alphabet. It has been argued that the Word Square provided a means for be-lievers to indicate their presence in a com-munity at a time when the Christian relig-ion was persecuted by the Roman authori-ties. If so, the Manchester Word Square may be the earliest evidence for Christian-ity in northern Britain.

The Manchester Museum holds sizeable archives from sites excavated by members of the University and by the former Man-chester Field Archaeology Unit. They pro-vide a major resource for research into Manchester's early history and archae-ology. Team RHX has requested permission to sample ceramic material associated with the Word Square.

See their blog for more updates from the museum http://ancientworldsmanchester.wordpress.com/

Publication update

RHX across the Atlantic

Left to right: Margaret Carter, Tim Scarlett, Moira Wilson and Sarah-Jane Clelland

See Professor Scarletts blog for more details on their ongoing research http://utahpotteryproject.blogspot.co.uk/

Professor Scarlett has been an enthusiastic sup-porter of RHX dating since the publication of the first dating results on archaeological material back in 2009. He immediately challenged three Michigan Technological University students, Helen Ranck, Patrick Bowen, and Jessica Beck, with replicating the tech-nique, with the help of the associated professor in MTU’s Department of Material Science and Engineer-ing, Jaroslaw Drelich. The results of these students’ work is now published in the Journal of the American Ceramic Society in a paper entitled “Rehydration/Rehydroxylation Kinetics of Reheating XIX-Century Dav-enport (Utah) Ceramic” (doi:10.1111/j.1551-2916.2011.04451.x). The MTU team have take a differ-ent approach to that used at Manchester, who believe in controlling the temperature and relative humidity to keep them constant, whereas the Michigan team’s ap-proach has been to take account of any fluctuations in these variables. More recently the Michigan team have published a sec-ond paper in the Journal of the American Ceramic Soci-ety, entitled “Modeling Rehydration/Rehydroxylation Mass-Gain Curves from Davenport Ceramics” (doi: 10.1111/jace.12175). In this paper they question the t1/4 law, however the t1/4 law only applies to the rehy-droxylation of fired-clay ceramic.

The Manchester contingent of Team RHX had the pleasure of meet-

ing with one our American counterparts, Professor Tim Scarlett from Michigan Technology University. Professor Scarlett is leading an American-based team who are also researching RHX dating. He was visiting the UK for the Society for Histori-cal Archaeology conference in Leicester this January and made time to stop by and visit Manchester during his stay.

It does not apply to either the process of rehydration nor the moisture uptake of any other components in the ceramic matrix, for example calcite or sand. These other components will not gain mass in the same manner but will contribute to the empirical measure-ments of mass. Both papers present fascinating research on the mineralogy of Davenport ceramics and we are extremely encouraged by the work done by the team at MTU. Particularly their recent paper “Effect of Humidity Instability on Rehydroxylation in Fired Clay Ceram-ics” (doi: 10.1111/jace.12262). Since then Professor Scarlett has gone on to secure funding from the National Science Foundation (NSF) to continue working on RHX dating but to extend it to a much larger collaborative project. The purpose of the NSF funded project is to allow his team at Michigan Technological University to coordinate an experiment involving different international teams of faculty and students (Michigan Technological University, Arizona State University, California State University and Tel Aviv University). The University of Manchester has been named collaborators offering support to-wards establishing pro-tocols and interpreting results. We have al-ready provided sam-ples of material we have analysed and are looking forward to of-fering our support to this project.