Friday, 19 November 2010

A Puzzling Process

An important part of the numismatic cataloguing that is being done at the Leeds Museum Discovery Centre is to assign catalogue numbers to coins that have not been listed already. Some of these coins are completely unknown, some are partially identified and some are wrongly identified! For me one of the biggest joys of numismatic research is the puzzle-solving that is involved in narrowing down ‘a coin’ to its very specific classification. So if you like crosswords and sudoku, follow this …

Obverse and Reverse:

To begin with what can we tell from this piece of an ancient coin? Luckily in 1988, a H. Williams classified some of the collection of Roman coins of England, so we know that this piece is an antonianus (a smaller denomination than the more familiar denarius) of Carausius, who was emperor of Britain from 287–293 AD. Beyond this there was little information.

The coin itself is worn and corroded so at a first glance it is easy to assume that there is little more information to be gleaned from the piece, yet there is enough detail remaining for us to do just that.

Close examination of the obverse shows that most of the inscription and much of the head is missing from the fragment, but for many coins, what the bust is wearing is as equally important for classification as the head and the wording around it. The clarity of the neck and shoulders shows that the bust was draped – a toga – but most importantly it shows that the bust is NOT cuirassed (armoured). The part of the head that we can see shows a radiate crown (the zig-zags), rather than a laurel wreath.

The reverse shows Pax holding a sceptre and an olive branch. Pax is the Roman personification of peace and is a common motif on the coins of Carausius. In fact the majority of antoniani that Leeds Museum holds feature Pax. What is most important about the depiction of Pax is that way the sceptre is held: it is held transversely across the body of Pax. This a rarer form of the Pax reverse type. The next important information we can glean from the reverse is that the mint-marks are just visible, with a S to the left of Pax and a P to the right.

Now we have four important numismatic characteristics for this coin:
Bust is not cuirassed.
Bust wear a radiate crown.
Pax holds her sceptre across her body
Mint-mark are S and P, either side of Pax’s body.

After this careful examination of the coin, we can begin to consult the reference volumes!

The main reference work for the coins of Carausius is found in volume V of Mattingley and Sydenham’s ‘Roman Imperial Coinage’ (RIC). What can be even more puzzling is that numismatic reference works can often seem to be written in a type of code. If you look at the page below, you see in the field labelled ‘obverse’ there is a number and then some letters. The number relates to the most common inscriptions, from 1 to 9; the letters relate to the types of bust and go from A to G.

This page list the types of Pax holding a transverse sceptre, from which we can narrow down the obverse types.

As the inscription is illegible we need to narrow down the letters that refer to the types of bust. For the ‘tranverse Pax’ types there are three possible bust types - A, C and F:
A: Radiate, draped bust, facing right.
C: Radiate, draped and cuirassed bust, facing right.
F: Radiate, cuirassed bust, facing r.

Immediately, since we know the bust is not cuirassed, we need to now only consider numbers from the page that are type A. So rather than us having to choose between numbers 118 – 123, our choice is now limited to 120 or 123.

Now we consult the page again, this time looking at the mint-marks column. Mint-marks have a special notation, to show where on the coin they are found:
Left reverse image│Right reverse image
Under reverse image

So we need to look to see if either 120 or 123 have mint mark notation like S│P. From that we can see that the piece is best categorised as number 123. In the Museum catalogue all our research is then written as RIC Carausius/123, showing the reference work, the emperor and the number to consult.

Why is this important I hear you ask?

It is important because the more pieces that are individually and correctly identified, the more detailed our knowledge of particular coinages becomes. When contextualised as part of the economic and political history for a particular time and place, then it greatly adds to what we already know.

Part of the joy of this internship is the process of sorting out the puzzle. Using skills of examination and deduction to get to a result, in this case a result no-one had reached before, is loads of fun!
Author: Lucy Moore, Leeds Museums and Galleries Intern 2010

Thursday, 18 November 2010

Great Ape Collar Bone

Whilst examining the fascinating and varied animal osteological collection at Leeds Museum Discovery Centre, I came across a rather unusual clavicle or collar bone. The bone was from a Great Ape, probably either a chimp or a gorilla and whilst this bone is nothing unusual, it caught my eye due to the pathologies present.

The clavicle had been broken and may have not been set causing an infection in the bone. It is even possible that this active infection killed the ape and caused it to be part of the collection!
To me this is one of the most interesting remains because it allows us a short glimpse into the life of this animal and how inadequate medical attention possibly caused its untimely death. What caused the break, I’m not entirely sure, but it could be a fall which can cause this type of fracture in humans.

Object Number: LEEDM.C.2010.925

By Sam Carter (intern with the natural science department, Summer 2010)

Sunday, 14 November 2010

Marquetry research, part 2: Chippendale's marquetry revealed

Jack Metcalfe and Dr. Heinrich Piening undertaking colour and dye analysis on the Chippendale writing table at Temple Newsam House.

Continuing on from Marquetry research, part 1: Some of Chippendale's furniture exhibits the finest English marquetry created, and stands with the best anywhere in the world. Jack decided for his next project he would research, catalogue, and do a technical analysis of every known piece of Chippendale marquetry, with a view to a second book. For the project, in addition to the research and cataloguing, he and a colleague are making a precise copy of the celebrated Diana and Minerva commode at Harewood House.
Another feature is the virtual recolouring of the faded colours of the Chippendale pieces researched.
The technical analysis has involved the use of an technique pioneered by Dr. Heinrich Piening, Senior Furniture Conservator and Scientist, Bayerische Verwaltung der staatlischen Schlosser, Munich, whom Jack met at the conference in Sweden
Heinrich presented in Sweden a stimulating paper on his recent research into identifying dyestuffs used on antique marquetry work, without affecting the integrity of the original work. UV-VIS Spectronomy (ultra-violet, visual) is a scientific technique that produces a white light across the specimen of veneer under test, at opposing angles of 0º and 45º, for a period of 50 milliseconds, whereupon some of the white light is absorbed and some is reflected. The reflected light is detected and split by a spectrometer. This in turn produces a unique wavelength for the dye pigment lurking below the veneer surface. The wavelength can later (back at the laboratory), be run against a computer library of known dye pigments, until a matching wavelength is obtained. In layman’s language matching wavelengths against library copies can be likened to finger printing or DNA.
In February 2008 Jack arranged for Heinrich to visit Leeds to test a range of marquetry furniture made by Thomas Chippendale between 1770 -1775, held at various locations across Yorkshire. The results of those tests will be an integral part of Jack's next book, titled “Chippendale Marquetry Revealed” due for publication around mid 2011. In addition, Heinrich carried out tests on a table made by the London-based French cabinet-maker Pierre Langlois around the same period. The table, forming part of the Temple Newsam collection includes marquetry motifs of floral work together with other neo-classical musical images.

The test results matched the same dyestuffs found on furniture made by Chippendale, suggesting that both London-based workshops purchased veneers already dyed from a central source. This makes sense since the dyeing process is as specialised in its application as it is in its equipment to perform the processes, therefore making it unlikely that either furniture maker would be sufficiently geared up or knowledgeable enough to dye their own veneers. This probably holds true for the whole trade, with dyed veneers being supplied by specialists.

Some of results of the Spectronomy tests on the Langlois table are as follows.

  1. Acanthus leaves framing the centre panel – Indigo carmine + barberry = green

  2. Ribbon above the acanthus leaves – wig tree = yellow

  3. same as 1.

  4. Flower outer petals attached to ribbon Brazil + wig tree = orange

  5. flowers right & left of 4 – brazil = red

  6. music sheets – no result = plain holly - colour white

  7. Inside left hand trumpet – wig tree = yellow

  8. Outside left hand trumpet – wig tree = yellow

  9. sheet music - same as 6

  10. Harp frame – barberry = yellow

  11. Harp strings – brazil+ barberry = orange or reddish?

Posted by Ian Fraser

Marquetry research, part 1

Lifelong Leeds resident Jack Metcalfe has, since taking early retirement, devoted his time to studying and learning the art of marquetry, the making of decorative images in wood veneers. This art, or craft, has been practiced for centuries, and is usually used to decorate and embellish furniture. Jack has achieved a high level of proficiency and is a published author. His book The Marquetry Course has sold well in Europe, and particularly in North America.
Since 2004 Jack has been getting his head around the marquetry that Thomas Chippendale decorated his furniture with. The trigger for this was the conservation treatments undertaken to the Harewood House writing table now in the collections at Temple Newsam House. During treatment, as various veneers had to be lifted for re-fixing, it became clear what the original colour scheme was. Holly, dyed greens, reds, purples, and its natural white, make up the vase and swags. The background uses the natural colours of Indian rosewood, tulipwood and satinwood. We mapped the colours.

Excited by the thought of the original polychrome appearance we did a little research into historic dyes, then dyed some holly to match the colours uncovered. For example, the greens are produced by an infusion of powdered Barberry bark and a pinch of turmeric (yellows), with vitriolated indigo (blue). It was possible to control the depth of green with the indigo. The purple of the vase, reminiscent of porphory, was successfully done with brazilwood dye. These dyes are plant derived. The scarlet red of historic textiles was often achieved with cochineal, derived from a species of Latin American beetle, with tin chloride as the mordant. We did the same and an amazing red resulted. With prolonged warm soaking the vital factor of full dye penetration was accomplished.

Jack then set to work making a copy of a door in what we are tolerably certain are the original colours, though perhaps not the original dyestuffs. The difference between new and old is amazing. The effects of oxidation, and bleaching from light and ultraviolet radiation have caused the colours to merge; light woods darken; dark woods and dyes fade, until everything is various shades of brown. I think sometimes it is difficult for us to comprehend how incredibly colourful some historic objects were; textiles and marquetry in particular. Jack gave a paper on this work and flew the flag for Temple Newsam at a marquetry conference in Sweden in May 2007, which also led to useful leads and contacts.

The next chapter of Jack's quest gets more interesting as he digs deeper into Chippendale's marquetry.

Posted by Ian Fraser

Friday, 5 November 2010

The Good, The Bad, and The Ugly

I am reminded regularly of the extraordinary variety of items in the collections at Leeds Museums and Galleries, like the exquisitely made and highly significant Harrison precision pendulum-clock

Il Buono

(picture by Jeff Darken)

And the Hinton House state bed, whose tester, the original construction of which is so poor that it was collapsing under its own weight, and it requires, essentially, re-engineering, giving it the structure it never had. The new structure supporting the collapsing parts will be entirely hidden behind the cornice.

Il Cattivo

And these examples of Victorian excess, papier-mache furniture, lacquered and heavily decorated with mother of pearl inlay and painted floral images. They remind me of the Little Britain character Bubbles De Vere, pretentious and tasteless.

Il Brutto

Posted by Ian Fraser