: Cadwraeth

I barhau â Blwyddyn Ryngwladol Tabl Cyfnodol yr Elfennau Cemegol y Cenhedloedd Unedig, rydym wedi dewis arsenig ar gyfer mis Awst.

Cadw’r Bwystfilod – Arsenig a Thacsidermi

Mae’r anifeiliaid tacsidermi yn un o atyniadau mwyaf poblogaidd yr Amgueddfa. Daw’r gair ‘tacsidermi’ o taxis (trefnu) a derma (croen), ac mae’n golygu mowntio neu atgynhyrchu sbesimenau anifeiliaid er mwyn eu harddangos neu eu hastudio.

Mae’r dechneg o greu tacsidermi wedi bod yn datblygu ers dros 300 mlynedd. Yn wreiddiol, doedd y technegau hyn ddim yn cadw’r sbesimenau’n dda iawn, a châi’r mowntiau eu colli oherwydd dirywiad neu drychfilod.

Gwnaed sawl ymgais i wella dulliau cadw, gan ddefnyddio amrywiaeth o ddeunyddiau fel perlysiau, sbeisys a halen ar ffurf powdrau, pastau a thoddiannau. Fodd bynnag, aflwyddiannus oedd y dulliau hyn ar y cyfan.

Yn y 1700au dechreuodd rhai tacsidermwyr ddefnyddio cemegau gwenwynig fel mwynau arsenig neu fercwri clorid i gadw eu sbesimenau. Oherwydd eu natur wenwynig, roedd y cemegau hyn yn atal dirywiad a difrod trychfilod ac yn gwneud i’r tacsidermi bara’n hirach.

Arweiniodd llwyddiant y cemegau hyn at ddatblygu triniaeth ‘sebon arsenig’ i helpu i gadw croen anifeiliaid. Roedd y sebon yn gymysgedd o gamffor, powdr arsenig, halwyn tartar, sebon a phowdr calch – fyddwn i ddim yn defnyddio hwn i ymolchi! Roedd y sebon yn galluogi i’r arsenig weithio mewn ffordd ymarferol drwy rwbio mewn i ochr isaf croen wedi’i lanhau a’i baratoi. Roedd hwn yn ddull poblogaidd iawn ac yn cael ei ddefnyddio mor ddiweddar â’r 1970au.

Nid yw arsenig yn cael ei ddefnyddio fel rhan o’r driniaeth erbyn hyn. Mae hyn oherwydd ei fod yn wenwynig ac yn beryglus i iechyd pobl, ond hefyd oherwydd bod technegau newydd wedi’u darganfod.

Elfen lwyd yr olwg yw arsenig anorganig (As, rhif atomig 33). Mae’n feteloid, sy’n golygu fod ganddo nodweddion metelig ac anfetelig. Mae pobl wedi bod yn ei ddefnyddio mewn amrywiaeth o ffyrdd ers canrifoedd – mewn meddyginiaeth, fel pigment ac fel plaladdwr. Mae arsenig a’i gyfansoddion yn wenwynau cryf iawn, yn ddrwg i’r amgylchedd ac yn garsinogenig. Mae’n wenwynig i bethau byw am ei fod yn tarfu ar weithgarwch ensymau sy’n rhan o gylch egni celloedd byw.

Yw hyn yn golygu fod ein sbesimenau tacsidermi hŷn, sy’n cynnwys arsenig, yn beryglus? Mae hynny’n bosibl os yw’r sbesimen wedi’i ddifrodi ac ochr isaf y croen yn dangos, ond ychydig iawn o risg sydd i sbesimenau cyfan cyn belled â bod camau synhwyrol yn cael eu cymryd megis gwisgo cyfarpar amddiffynnol wrth symud neu wneud gwaith ar sbesimen.

Heddiw, mae’r rhan fwyaf o sbesimenau sy’n cael eu harddangos gennym yn cael eu trin heb ddefnyddio cemegau gwenwynig, ond mae mwy o risg i’r sbesimenau hyn gael eu difrodi gan drychfilod. Felly rydym yn monitro ein casgliadau er mwyn cadw golwg am arwyddion o bla trychfilod, ac yn eu trin gyda dulliau diogel a chynaliadwy megis rhewi os yw hyn yn digwydd.

Ond mae’n rheswm da arall i beidio cyffwrdd y sbesimenau...

Amgueddfa Cymru helped direct me to a career in heritage by drawing my attention to the possibility of a career in museums at a “career speed dating” event. I would go on to volunteer with National Museum Cardiff, whilst studying.

Volunteering as part of the museum’s preventive conservation team, we carried out a wide range of tasks from repackaging lichen, to carefully carrying jade, cleaning paintings currently on display all the while talking to the public about the importance of preventive conservation and promoting part of the Museum traditionally shielded from view. It could be just a few people or what seemed like hundreds of school children, every day brought a different experience.

Volunteering brought the reality of the sector and a chance to learn new skills and experiences which were invaluable to my understanding of what museums are and who they are for; fulfilling my personal reasons for volunteering.

The volunteer programme was flexible, reflecting my own needs not just its own. The programme allowed me to develop as I wanted and when it came time to end my time volunteering with Amgueddfa Cymru it was natural. I had succeeded in what I wanted to achieve, and I was supported to continue my development beyond the museum, not expected to stay when it was no longer practical.

I will always remember having the opportunity to be part of the preventive conservation team, I am sure the team will not forget my Elmer the Elephant style shirt, immortalised in many presentation slides and pull up banners (see photos). I now work for the Cynon Valley Museum as a Museum Co-ordinator and advocate for museums through EMP Wales (Emerging Museum Professionals) and FOH. 

Follow me on twitter: @TregaskesW @FoHMuseums @EMPCymru @cynonvalleymus

What do you do if you have minerals in your collection that have a tendency to react chemically? For our research student Kathryn Royce this means: growing minerals from a super saturated solution, then sticking the crystals in a climate chamber for a few weeks and forcing them to dehydrate.

Yes, you read right, some minerals can dehydrate. There is a good number of mineral species which are poly-hydrated, meaning, minerals that contain water molecules as part of their crystal structure. Many of these mineral species can, under certain conditions, lose some of these water molecules. This process actually turns the mineral into a different mineral – just one with a lower hydration status.

For example, the mineral melanterite (FeSO₄ · 7H₂O), which has 7 water molecules, may lose some water molecules if kept at a relative humidity below 57%. The resultant products include either the mineral siderotil (same chemical formula but only 5 water molecules) or rozenite (4 water molecules). In the context of wanting to preserve melanterite in a museum collection, the dehydration products siderotil and rozenite, whilst minerals in their own right, would be classed as deterioration products and, hence, their appearance be undesirable.

To understand this process, and define how we would characterise the concept of ‘damage’ to mineral specimens, Kathryn is now analysing the deterioration products using a combination of different analytical techniques, including X-ray diffraction, electron microscopy, Raman spectroscopy and computerised tomography scanning. The results will help us develop a methodology for long-term monitoring of geological collections in museums and improve the care of such collections in museums.

This research is being undertaken at National Museum Cardiff in collaboration with the School of Geography and Environment at University of Oxford and the EPSRC Centre for Doctoral Training in Science and Engineering in Arts, Heritage and Archaeology (SEAHA), and kindly supported by OR3D, BSRIA, the Barbara Whatmore Charitable Trust, the National Conservation Service, and the Pilgrim Trust.

Find out more about Care of Collections at Amgueddfa Cymru - National Museum Wales here and follow us on Twitter. 

One of the best reasons for housing heritage collections inside buildings is that the building keeps the weather out. Paintings, fossils, books and skeletons are best kept dry, and walls and roofs protect our collections (as well as staff and visitors) from the elements.

In addition, many of the objects in our collections also need specific temperature and humidity ranges to prevent them from suffering damage. Too high a humidity can cause swelling of wood, for example, initiating cracks in objects, or, if humidity gets even higher, mould growth. Therefore, National Museum Cardiff has a complicated air conditioning system. This system is more than 40 years old and has been maintenance-intensive and inefficient for some time.

We are happy to report that, after several years of planning, we have just completed the installation of new chillers and humidifiers at National Museum Cardiff. The purpose of chillers in the museum is to provide cold water – for lowering the temperature of galleries and stores in the summer, and for dehumidifying stores and galleries if there is too much moisture in the air. Humidifiers achieve the opposite effect: they increase humidity in stores and galleries if it is too low. Low humidity is usually a problem during the winter months – you may have experienced your skin drying out at home when you have the heating on in winter. To prevent our collections drying out we cannot apply skin cream; instead, we maintain a minimum level of humidity in stores and galleries.

The chillers and humidifiers have been commissioned now, and are working well. They have already proved that the control of our indoor environments is better than it was before. A very positive side effect of the new technologies is that they are much more efficient than the old equipment. In fact, they are so efficient that we are anticipating to shave almost 50% off our annual electricity bill for National Museum Cardiff, saving the planet more than 500 tonnes of carbon dioxide every year. That is the equivalent of taking 100 cars off the road, or the average energy a family home uses in 38 years.

By investing in such new technologies, Amgueddfa Cymru – National Museum Wales continues to ensure the safe storage and display of the nation’s heritage collections, whilst at the same time making a massive contribution towards the National Assembly’s commitment to reduce carbon emissions by 80% by 2050 (Environment Wales Act 2016).

Find out more about Care of Collections at Amgueddfa Cymru - National Museum Wales here and follow us on Twitter. Follow the progress of the maintenance works during the coming months in 2019 on Twitter using the hashtag #museumcare.

Back in 1998, long before I started my current job as Senior Textile Conservator at St Fagans National Museum of History, I spent two work experience placements at the museum, helping my predecessor Clare Stoughton-Harris.  I had just started on my 3-year post-grad course in Textile Conservation the previous year.  The course was based in apartments within Hampton Court Palace.  I saw an ad for a placement at St Fagans on the Centre’s noticeboard and decided to apply. A few weeks later, I found myself driving over to Cardiff to start my placement.

My first stint was for 3 weeks, over the Easter Holidays.  The work mainly consisted of preparing St Fagans castle for re-opening after refurbishment, so it involved a lot of surface cleaning, but we also got around to wet cleaning a carpet.  The image shows Clare sponging the carpet in the detergent bath in the studio. 

When I came back in the summer, my project was to improve the storage conditions of the shoe collection.  Most shoes were stored on open shelving, with several pairs stacked on top of each other.  Some were not wrapped at all and were gathering dust, and others were wrapped in yellowed newspaper as you can see in the 2 pictures below.  That’s me, unwrapping and examining some children’s shoes!

As they were, the shoes were also very inaccessible as it was impossible to know which pair was wrapped in each bundle of tissue paper.  So I remember assembling endless flat pack boxes and re-packing the shoes… so here they were in their lovely new storage boxes:

Once the contents of the Old Costume Store moved into the Collection Centre at St Fagans in 2008, the project was improved upon by adding thumbnail images of each pair, clearly attached to the outside of the box, so here they are in their current configuration!

From 1998, it took another 7 years, and jobs with the National Trust, in Norfolk, a private studio in Dublin and 2 years at the British Museum before I was became the Senior Textile Conservator at Amgueddfa Cymru. Now I have the occasional pleasure of overseeing students myself and can return the favour of giving them the chance to expand their experience and help them along their career path!