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A
small candlestick of cast brass inlaid with
silver and gold. The shape of the candlestick
and its coat of arms (possibly of the Boldu
family of
Venice) indicate that it was made for export to
Europe (Ht 12.4 cm.
Damascus c. 1400)
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[copyright The
British Museum].
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“ The use of pen cases of steel has overtaken scribes in
our time, both chancery and treasury scribes. They pay
extravagant prices for them and beautify them
excessively. Brass is the most used... on account of its
rarity and costliness. It is the prerogative of the
highest ranks of leadership, like the vizirate and
similar ranks…Government scribes use long ones with
rounded ends, elegantly shaped. They use them because
they seek lightness and because they are accustomed to
use scrolls in their writing”.
So
wrote the Mamluk historian, Qalqashandi, (AH.
756-82/A.D. 1355-1418), of the fashion of pen cases in
the age of large silver and copper inlaid bronze
inkwells with lids. The modern convenience of fountain
pens with their own ink-supply is also an invention of
much greater antiquity. In an early tenth century
Arabic manuscript entitled Kitab al-Mjalis wal
Musa’irat (the book of Assemblies and
Discussions), written between 969 and 975 AD by
al Qadi al Nu’man Ibn Muhammad,
the chief judge of the caliph Mu’izz, who
established the Fatimid dynasty in Egypt in 969 AD,
leaves no doubt that the Caliph refers to a true
fountain pen:
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The Egyptian scholar, Hassan El-Basha
Mahmoud, in 1951, first noticed this and translated it:
When Mu’izz mentioned
the pen he described its merits and regarded it as the
symbol of the secret of knowledge; he then said he would
like to make a pen which would write without the need of
an ink-pot.
Such a pen, said the Caliph, would be
self –supplying and have the ink inside. One could
write what one wanted with it but as soon as one
relinquished it the ink would disappear and the pen
would become dry. The writer could keep such a pen in
his sleeve without fearing any mark or filtration of the
ink for the ink would filter only when the pen wrote. It
would certainly be a wonderful instrument and one
without precedent.
In a few days the craftsman to whom the pen had been
described brought a model made of gold. After filling it
with ink, he was able to write with it. But as more ink
came out than was needed, the craftsman was ordered to
alter it. Finally the pen was brought back repaired. It
was turned over in the hand and tilted in all directions
and no ink appeared. But as soon as he took it and began
to write, he wrote the best hand for as long as he
wished and when he took the pen away from the paper the
ink vanished. Thus I beheld a wonderful work the like of
which I had never thought to see.”
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Cast Persian
pen box (OA 1891-6-23.5) inlaid with gold
and silver (length 19.5 cm. In the
radiograph dense areas such as the gold
inlay and the tin-lead solder smeared across
the base appear paler grey . The enlargement
on the right hand end of the base shows
traces of the cast structure and the black
spots are bubbles trapped in the cast metal.
The walls of the penbox are only 1.5 mm
thick so the discovery that it was cast not
hammered was an unexpected discovery.
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[copyright
The British Museum]. |
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The translation and interpretation
of such contemporary texts have provided art historians
and scholars with important source material in art
historical research for analysis of style in hotly
disputed matters of provenance. A case in point, the
provenance of ‘ Veneto-Saracenic’ metalwork objects. A
large group of Islamic metalwork produced between the
fourteenth and sixteenth centuries which display a
mixture of Middle Eastern and European elements in their
style and technique.
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Scientists say, however, in some
cases the same objects in this group were being
attributed by different scholars to Cairo, Syria, West
Iran and Anatolia, with no general agreement on which
(if any) of these objects were made within the Venetian
empire by local craftsmen imitating Islamic metalwork.
Clearly, the method of analysis of
stylistic similarities in the shape and decoration of
metalwork objects has limitations. Scientists now hope
their work on these objects may help to persuade any
lingering doubters of the Middle Eastern provenance of
these so-called ‘ Veneto-Saracenic metal wares’.
Dr. Susan La Niece, a metallurgist and one of the
scientists at The British Museum’s Department of
Scientific Research, who have examined ‘ Veneto-Saracenic’
metalwork, as part of a larger survey of Islamic
metalwork in the collections of the British Museum.
Her most recent (2003) and most important article on
Islamic metalworking technology, ' Scientific Research
in the Field of Asian Art ' ed. Paul Jett. Archetype,
London, is an overview of the manufacturing methods of
all the brass vessels that have been examined for a new
catalogue Metalworks from the Arab World in the British
Museum.
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Radiograph of a Veneto-Saracenic brass tray
(OA 1957-2-2.3) diameter 40 cm. The
concentric pattern of dark patches is made
by the impressions of the hammer used in its
manufacture. The magnified detail
accentuates the traces of the worn silver
inlay decoration which now is only preserved
in the finely punched keying on the tray.
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[copyright
The British Museum].
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Islamic brass ewer with silver and copper
inlays, Mosul-Iraq, dated 1232 AD.
An image of both sides of the ewer produced
on the radiographic film shows it was made
up from several pieces of sheet brass,
soldered together. The X-rays revealed
soldered joints at the neck, handle and base
as well as around the hole for the missing
spout.
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Dr. Susan La Niece explains
the significance and the aim of analytical and
technological scientific study of ‘ Veneto-Saracenic’
metalwork objects.
“ Generally, museum displays give the impression that
Islamic metalwork consists almost entirely of highly
decorated brass vessels, but this is a trick of
survival. These pieces have been treasured for
generations. The survival of everyday, household items
has been less good, as has the survival of precious
metal vessels. The literary sources frequently refer to
gold and silver vessels, furniture and jewellery, and
miniature paintings of courtly scenes are full of such
items. Islamic gold and silver objects have not survived
in any quantity because of religious disapproval of
burial of goods with the dead. Instead these objects
were melted down for their precious metal content, or
reworked to the latest fashion. Most surviving medieval
Islamic gold and silver comes from hoards of treasure
buried for safe-keeping by the owners in times of
trouble, and never retrieved. Our knowledge of simple,
utilitarian objects is also poor.
There must have been an enormous amount of undecorated,
functional metalwork essential to domestic life, such as
roughly constructed water carriers and cooking pots. Few
of these have survived, as they were thrown away or
melted for scrap when they wore out.
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Excavations of urban sites provide
examples but many more excavations are needed before we
can assess the range of this type of material.
The
Scientific Study of Islamic brass metalwork
The British Musuem’s collections of
Islamic brass metalwork are currently the subject of a
detailed scientific study, the results of which will
appear in a few years time in a catalogue entitled : -
Metalworks from the Arab World in the British Museum
by Rachel Ward and Dr.Susan La Niece. It will be published
by BM press.
The aim of
the scientific study
A few of the objects include
inscriptions which tell us the date it was made, the
name of the patron it was made for, and, more rarely,
the place of manufacture and the name of the maker. For
the majority of objects, however, nothing at all is
known about their origins, Stylistic similarities in the
shape and decoration can be used to group these unknown
pieces in relation to those about which more is known,
but there are obvious limitations to this method. This
is where a scientific approach is essential to the study
of the metalwork. The scientific work on these objects
can not only enable to define what they are made of and
how they were made, but also to use this information to
add to the knowledge we have of advances in metal
technology in the Middle East from the beginning of the
Islamic era, to study the interaction between the
Islamic world and the cultures surrounding it and to
identify workshop groupings.
The chief tools of the scientific
research are:-
microscopy-
particularly for studying tool marks from manufacture
and decoration of the vessels.
analysis
- to identify the
metal composition.
Radiography
– to reveal the manufacture technique, joins and
repairs, both ancient and modern.
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Metal
Analysis
The programme of metal analysis was
begun a number of years ago by Dr Paul Craddock, using
atomic absorption analysis (AAS) for major elements
(i.e. the ingredients deliberately mixed together by the
metalsmith to make the required alloy eg. copper and
zinc to make brass, and additional lead to help with
casting) and trace elements (i.e impurities in the
metal, which may be able to tell you about the original
ore and processes it went through to be made into
metal). Analytical techniques have advanced during this
period and the analyses are being completed by Duncan
Hook, using inductively coupled plasma atomic emission
spectrometry ICP-AES). Over 300 objects have been
analysed and published –
P.T. Craddock, S.C. Susan La Niece and D.R Hook ‘ Brass in
the Islamic World’ in 2000 years of zinc and brass-BM
Occasional paper 50. Revised edition 1998.
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A
round bottomed bowl with a tight fitting lid;
brass with silver inlays and a European style
shield for family arms. (OA1878-12-30, 698).
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[copyright The
British Museum].
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Almost all the
copper alloy artefacts from the Islamic collections have
been found to be made of brass, which is an alloy of
copper with zinc. Only few specialised groups of objects
were made of bronze (an alloy of copper and tin). A
small but distinctive group of drinking vessels from
Persia were made of a special bronze with an unusually
high tin content (around 20% tin ) which gave the metal
good resistance to corrosion-essential if they were used
for acidic drinks like wine or fruit juice. Some
utilitarian objects were made of beaten copper.
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inlaid brass candlestick second half of
13th century. Damascus.
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[copyright The
British Museum].
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The use of brass
rather than bronze is not surprising because tin is not
readily available in the Middle East, but sources of
zinc are abundant throughout Anatolia, Iran and
Afghanistan. These zinc mineral deposits are
predominantly of sphalerite (zinc sulphide, ZnS) with
only relatively minor amounts of smithsonite (zinc
carbonate, ZnCO3) compared to Western Europe and to
China. This had important repercussions for Islamic
brass production technology. Although metallic zinc was
known from the beginning of the 16th century
AD (the understanding of how to smelt ores to produce
metallic zinc came relatively late because zinc boils
below the temperature at which it is smelted and thus
has to be condensed from a gas), there is no evidence
that metallic zinc was used in the Islamic world for the
production of brass. Instead brass was produced by a
variation on the cementation process, a technology
inherited from the preceding Roman and Byzantine
civilisations. There are few contemporary Islamic
descriptions of the final cementation stage, in which
zinc oxide is mixed with the copper in the crucible to
produce the brass, but rather more on the preparation of
ore to produce the zinc oxide needed for this process.
To convert the sulphalerite into a usable form it was
roasted to convert the sulphide to oxide. Many of
contemporary accounts describe a sublimation process in
a heated, sealed container, where the fumes of zinc
oxide, or tutiya in Persian, were condensed for
collection onto clay pegs. This process served to purify
it from the traces of other metals present in the zinc
or, particularly sulphur and iron. The analysis
programme at the British Museum has shown that iron
content in Islamic brass is very low, but that in
European brasses the iron content was generally higher.
This is thought to be because zinc carbonate ores were
being used in Europe, and these ores did not need the
intermediate preparation stage of being sublimed and
consequently they were less purified than the zinc ores
of the Middle East.
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| Nickel, another trace level metal
found in brass, has been found to have been increased
sharply in the 15th and 16th
centuries AD in Islamic brasses. A similar increase is
seen in European brasses from the 11th
century. This suggests that, from the 15th
century, the Islamic world was sharing some of the more
important sources of copper being used by European brass
makers. This is backed by contemporary documentary
evidence for trade in the Eastern Mediterranean at that
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Decorative techniques
Much of the appeal of
Islamic metalwork lies in its surface decoration.
Designs were created by repousse, piercing, chasing and
engraving. Repousse, - hammering the metal from inside
the vessel against a firm but yielding material such as
bitumen-created a relief design which could be extremely
elaborate.
Piercing was particularly popular.
Brass was inlaid with silver and sometimes copper and
gold to add colour. Under the microscope it is possible
to see the fine too lmarks which provide the keying to
hold the thin sheet and fine wire inlays in place.
In addition to metal inlays, a black
material was used to provide a contrasting background to
the designs. This black material has clearly been
applied hot and liquid as tiny bubbles are still visible
on its surface under magnification. This material has
been described as mastic, tar and bitumen, but no
scientific identification was available until this
project enlisted the help of Dr Raymond White, a
scientist at the National Gallery, London. It was
discovered that many of the inlays are indeed of
bitumen, a black residue of crude petroleum which has
many sources in the Middle East. More surprisingly, some
of the black inlays were found to be of pitch, which is
derived from distillation of conifer resins. This
discovery has opened up the possibility of new methods
of differentiating between groups of objects and the
workshops.
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A spherical
brass incense burner, pierced and inlaid with silver.
The technique of Piercing was particularly used
in the manufacture of incense burners, to
decorative effect as well as to release the
perfumes.
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[copyright The
British Museum].
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[This work has been published- Ward,
R. Susan La Niece, S., Hook D. and White R. 1995.
‘ Veneto-Saracenic metalwork: an
analysis of the bowls and incense burners in the British
Museum in Trade and Discover : The scientific study of
artefacts from post-Medieval Europe and beyond, ed D.R.
Hook and D.R.M Gaimster BM occasional paper (109).
Results from scientific examination
of this group of metal works has provided scientists
with evidence which has been used to distinguish
different workshops traditions, to differentiate between
European and Middle Eastern manufacture, and to argue in
favour of a Middle Eastern (rather than Venetian)
provenance for them all.
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