: Cyffredinol

Yn 2019 mae Tabl Cyfnodol yr Elfennau Cemegol yn 150 mlwydd oed (gweler UNESCO https://www.iypt2019.org/). Mae hyn yn gyfle i feddwl am wahanol agweddau’r tabl cyfnodol, gan gynnwys effeithiau cymdeithasol ac economaidd elfennau cemegol.

Sylffwr yw’r bumed elfen fwyaf cyffredin (yn ôl màs) ar y Ddaear, ac mae’n un o’r sylweddau cemegol gaiff ei ddefnyddio fwyaf. Ond mae sylffwr yn gyffredin tu hwnt i’r ddaear: mae gan Io – un o leuadau Galileaidd y blaned Iau – dros 400 o losgfynyddoedd byw sy’n lledaenu lafa llawn sylffwr, gymaint ohono nes bod arwyneb y lleuad yn felyn.

Alcemi

Câi halwynau sylffad haearn, copr ac alwminiwm eu galw’n “fitriol”, oedd yn ymddangos mewn rhestrau o fwynau a wnaed gan y Swmeriaid 4,000 o flynyddoedd yn ôl. Câi asid sylffwrig ei alw’n “olew fitriol”, term a fathwyd gan yr alcemydd Arabaidd Jabir ibn Hayyan yn yr 8fed ganrif. “Brwmstan” oedd yr hen enw am sylffwr yn llosgi, ac arweiniodd hyn at y gred fod Uffern yn arogli fel sylffwr.

Mwynoleg

Anaml iawn y gwelir sylffwr pur – mae fel arfer i’w ganfod fel mwynau sylffid a sylffad. Mae sylffwr elfennol i’w weld ger ffynhonnau poeth, daeardyllau hydrothermol ac mewn ardaloedd folcanig lle gellir ei fwyngloddio, ond prif ffynhonnell sylffwr ar gyfer diwydiant yw’r mwyn haearn sylffid, pyrit. Ymysg mwynau sylffwr pwysig eraill mae sinabar (mercwri sylffid), galena (plwm sylffid), sffalerit (sinc sylffid), stibnit (antimoni sylffid), gypswm (calsiwm sylffad), alwnit (potasiwm alwminiwm sylffad), a barit (bariwm sylffad). O ganlyniad, mae’r cofnod Mindat (cronfa ddata wych ar gyfer mwynau) ar gyfer sylffwr yn un go hir: https://www.mindat.org/min-3826.html.

Cemeg

Mae sylffwr yn un o gyfansoddion sylfaenol asid sylffwrig, gaiff ei alw’n ‘Frenin y Cemegau’ oherwydd ei fod mor ddefnyddiol fel deunydd crai neu gyfrwng prosesu. Asid sylffwrig yw’r cemegyn gaiff ei ddefnyddio amlaf yn y byd, ac mae’n ddefnyddiol yn bron bob diwydiant; gan gynnwys puro olew crai ac fel electrolyt mewn batris asid plwm. Caiff dros 230 miliwn tunnell o asid sylffwrig ei gynhyrchu bob blwyddyn dros y byd.

Rhyfel

Powdr gwn, cymysgedd o sylffwr, siarcol a photasiwm nitrad a ddyfeisiwyd yn Tsieina yn y 9fed ganrif, yw’r ffrwydryn cynharaf y gwyddom amdano. Sylwodd peirianwyr milwrol Tsieina ar botensial amlwg powdr gwn, ac erbyn OC 904 roeddent yn taflu lympiau o bowdr gwn ar dân gyda chatapyltiau yn ystod gwarchae. Mewn rhyfel cemegol 2,400 o flynyddoedd yn ôl, defnyddiodd y Spartiaid fwg sylffwr yn erbyn milwyr y gelyn. Mae sylffwr yn un o gyfansoddion pwysig nwy mwstard, sydd wedi bod yn cael ei ddefnyddio fel arf cemegol ers y Rhyfel Byd Cyntaf.

Fferylliaeth

Mae gan gyfansoddion sylffwrig bob math o ddefnydd therapiwtig, gan gynnwys trin microbau, llid, feirysau, clefyd siwgr, malaria, canser a chyflyrau eraill. Mae llawer o gyffuriau yn cynnwys sylffwr. Ymysg yr enghreifftiau cynnar mae sylffonamidau, “cyffuriau sylffa”. Mae sylffwr yn rhan o sawl gwrthfiotig, gan gynnwys penisilin, ceffalosborin a monolactam.

Bywydeg

Mae sylffwr yn un o elfennau hanfodol bywyd. Mae rhai asidau amino (cystein a methionin; asidau amino yw cyfansoddion strwythurol protein) a fitaminau (biotin a thiamin) yn gyfansoddion organosylffwr. Mae deusylffidau (bondiau sylffwr-sylffwr) yn rhoi cryfder mecanyddol ac anhydoddedd i’r protein ceratin (sydd mewn croen, gwallt a phlu). Mae gan lawer o gyfansoddion sylffwr arogl cryf: mae arogl grawnffrwyth a garlleg yn dod o’r cyfansoddion organosylffwr. Nwy hydrogen sylffid sy’n rhoi arogl cryf i wyau drwg.

Ffermio

Mae sylffwr yn un o’r prif faetholion ar gyfer tyfu cnydau. Mae sylffwr yn bwysig gydag ymlifiad maetholion, cynhyrchu cloroffyl a datblygiad hadau. Oherwydd hyn, mae asid sylffwrig yn cael ei ddefnyddio’n helaeth fel gwrtaith. Mae tua 60% o’r pyrit gaiff ei fwyngloddio yn cael ei ddefnyddio i gynhyrchu gwrtaith – gallech ddweud mai pyrit sy’n bwydo’r byd.

Yr Amgylchedd

Mae anfanteision i ddefnyddio sylffwr: mae llosgi glo ac olew yn creu sylffwr deuocsid, sy’n adweithio gyda dŵr yn yr atmosffer i greu asid sylffwrig, un o brif achosion glaw asid, sy’n troi llynnoedd a phridd yn asidig ac yn difrodi adeiladau. Mae draeniad asidig o fwyngloddiau, un o ganlyniadau ocsideiddio pyrit wrth fwyngloddio, yn broblem amgylcheddol fawr, ac yn lladd llawer o fywyd mewn afonydd ledled y byd. Yn ddiweddar, defnyddiwyd carreg galchaidd yn cynnwys llawer o pyrit fel ôl-lenwad ar gyfer stadau tai o gwmpas Dulyn. Achosodd hyn ddifrod i lawer o dai wrth i’r pyrit ocsideiddio. Cafodd yr achos ei ddatrys gan y “Pyrite Resolution Act 2013” a roddodd iawndal i berchnogion tai.

Cadwraeth Sbesimenau Amgueddfa

Oherwydd bod sylffidau haearn yn fwynau hynod adweithiol, mae’n anodd eu cadw mewn casgliadau amgueddfeydd. Am ein bod ni’n gofalu am ein casgliadau, sy’n cynnwys gwella arferion cadwraeth o hyd, rydym wastad yn chwilio am ffyrdd newydd o warchod mwynau bregus. Mae ein project diweddaraf, ar y cyd â Phrifysgol Rhydychen, yn cael ei gynnal gan ein myfyriwr ymchwil doethurol, Kathryn Royce. https://www.geog.ox.ac.uk/graduate/research/kroyce.html.

Dewch i’n gweld ni!

Os yw hyn wedi codi awydd arnoch i ddysgu mwy, dewch i weld ein sbesimenau sylffwr a pyrit yn Amgueddfa Genedlaethol Caerdydd. amgueddfa.cymru/caerdydd, neu gallwch ddysgu am fwyngloddio a diwydiannau tebyg yn Big Pit Amgueddfa Lofaol Cymru https://amgueddfa.cymru/bigpit/ ac Amgueddfa Lechi Cymru https://amgueddfa.cymru/llechi/.

The shrine of St David in St David’s Cathedral, Pembrokeshire, was an extremely important pilgrimage site in the Middle Ages. Two pilgrimages there were worth one to Rome, and thousands of people would have visited before the shrine was destroyed at the Reformation.

Inspired by the ‘Beneath our Feet’ project run by Narberth Museum and Tenby Museum and Art Gallery, which is looking at the theme of pilgrimage in Pembrokeshire, Saving Treasures; Telling Stories decided to find out more. What did those long-ago travellers leave behind them?

Pilgrim Objects

Two kinds of objects were commonly associated with pilgrims in the Middle Ages: ampullae, and badges.

Ampullae were little lead scallop-shaped flasks containing holy water that were pinned to clothing or hung around the neck in the belief that they offered spiritual protection. You might expect to find large numbers of them in Pembrokeshire, with its important holy shrine.

It seemed a fair bet that local metal detectorists had found plenty over the years.

But, a search on the Portable Antiquities Scheme (PAS) database, where over a million detectorist finds are recorded, revealed some surprises.

In fact only SIX examples from Pembrokeshire have been recorded with PAS – a surprisingly small amount! Surely there should be many more?

To compare, we looked at the records for Kent, home of medieval England’s most important pilgrim destination – the shrine of St Thomas Becket at Canterbury Cathedral. Even here, only 50 pilgrim ampullae have been recorded with PAS, not such a huge number considering the many thousands of people who travelled there.

Contrast this with Lincolnshire, where 232 ampullae have been recorded, the biggest number of any county in Wales and England. Lincoln Cathedral boasted two important shrines (both to saints called Hugh), but this does not explain such a big difference in numbers.

What’s going on?

Confused, we turned to pilgrim badges. These were usually made of lead or pewter and depicted saints, letters and religious scenes and symbols. They were bought at shrines as souvenirs and pinned to clothing.

Surely lots of these cheap objects would have been lost by the visitors to St David’s?

But a search on the PAS database turned up NO examples from Pembrokeshire at all!

Even in St Thomas Becket’s Kent, no more than 11 badges have been recorded with PAS. Greater London has by far the highest number, at 119.

Then we saw that five pilgrim badges had been reported from Swansea, which seemed unusual as there was no important medieval shrine in the town. One of them was a badge of none other than Thomas Becket himself. How had that got there?

It turned out that each one of these badges had been discovered, not in the city itself, but under the sands of Swansea Bay.

Intrigued, we chose a random sample of the London badges and discovered that they had all been found in the River Thames.

We checked the find spots of the ampullae, and sure enough, two had been found on Tenby beach and two others in the coastal village of Manorbier. There was a definite watery theme!

Giving thanks?

In an age when travel was difficult and dangerous, ships were the fastest method of transport, though not necessarily safe.

So it makes sense that pilgrims going on long journeys would travel at least part of the way by water, and would be relieved and thankful when they reached the shore safe and sound. The evidence of all these badges and ampullae dug from the sands and fished from the Thames suggests that returning pilgrims threw them into the water, perhaps as a way of giving thanks for a safe return.

Dewch i ailddarganfod trysor Rhufeinig ddaeth i’r fei yng Nghaerllion ym 1926!

Defnyddiwch yr Ap i archwilio'r Amffitheatr a'r Barics yng Nghaerllion. Dilynwch gliwiau a chwrdd â chymeriadau hanesyddol i helpu chi i ddarganfod trysorau'r Amgueddfa - lle cawsant eu darganfod un wreiddiol. Os dewch o hyd iddynt i gyd byddwch yn agor rhith-Amgueddfa Lleng Rufeinig Cymru. Mae'r Ap hwn yn brosiect partneriaeth rhwng Amgueddfa Cymru a Cadw. Mae'n cysylltu trysorau amgueddfeydd â'r lleoedd lle cawsant eu darganfod yn y safleoedd hanesyddol a gynhelir gan Cadw yng Nghaerleon.

Sut i chwarae:

• Defnyddiwch eich dyfais a'r map trysor i ganfod y chwe chliw cudd yn yr amffitheatr a'r barics.
• Rhaid i chi gerdded i bob un o'r chwe chliw llun yn y grid.
• Pan fyddwch chi'n agosáu at y man iawn bydd ceiniog yn ymddangos ar eich dyfais. 
• Pwyswch y geiniog i weld y cliw a chasglu pob ateb i ganfod yr allwedd sy'n agor yr Amgueddfa Lleng Rufeinig Rithwir.

Cwestiynau Cyffredin

• Mae'r ap yn gweithio orau ar Android 4.3 a'r iOS 9.1 neu yn hwyrach. Ni fydd yr ap yn gweithio ar rai ffonau android syml.
• Mae'r ap yn defnyddio data yn ystod y profiad
• Os ydych yn cael trafferth lawrlwytho'r ap, sicrhewch fod gennych gysylltiad gwe da a digon o le ar eich ffôn.

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Hi all, I’m Pip Diment from the Exhibitions team, and I'm one of a group of staff volunteering to care for the six live snakes we are housing as part of the 'Snakes’ exhibition at National Museum Cardiff.

Our exhibition is now open and runs to 15 September 2019. I was part of the team who cared for the snakes for the second two weeks of the exhibition run. We were trained by Guy Tansley from Bugsnstuff and he showed a group of us volunteers how to check on the snakes safely and provide basic care.

We are not required to feed the snakes – we have Dr Rhys Jones generously helping us with that. Our tasks are to change the water daily, remove any poo, ureic acid crystals (wee!) and calcium plugs, also to remove any shed skin and to check the snakes are not too cold or hot and that they are ok. These checks are all done daily by a team of two or three volunteers.

On my first day volunteering I worked with Melissa Hinkin (from Artes Mundi, who is a snake enthusiast) and Vic le Poidevin (from our Events team). There was great excitement the first morning as Prestwick, the Jungle Carpet Python had shed her skin and had an enormous poo!  She’s a fairly large snake so it shouldn’t have been a surprise, but it was huge! Like a large dogs! The skin itself came off in two parts and is now being used as part of the handling collections (not too much handling as it is fragile!). Underneath all that shed skin Prestwick has now emerged even more beautiful with her skin a stunning irridescent effect. And this was still only day one.

On day two I worked with Christian Baars (from Conservation) and Robin Maggs (from Photography). Once again, much excitement as Keith, the Royal Python, shed his skin overnight. Much smaller poo – smaller snake, so made sense! He also looked much more beautiful after shedding his skin.

Days three and four were not as eventful – only water changing and general checks required. Everyone seems very healthy and happy, and we are following their care instructions meticulously to ensure they stay that way. 

I admit I have an unhealthy interest in snake poo – and for the end of my first week we’ve had another poo! This time, again, from Keith. I am not the only one now excited by snake poos – see Robin and Christian admiring Keith’s offering (look closely it has substrate on it which makes it looks like it has eyes!)

I’m so glad I agreed to volunteer. I’ve held snakes before, but never spent so much time with them. I love that they all have great names and their own characters:

Thanks for reading. You can read some of our other snake blogs here, here and here.

The exhibition runs till 15 September 2019, entry charges do apply, and all your contributions go towards bringing you even bigger and better exhibitions in the future.

Please note that there is no live handling of the snakes within the exhibition. In August we’ll be having snake handling sessions for the public – see here for details of booking.

Also, make sure you come and visit us this saturday (10 August) for our Venom Open Day!

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.