Series editors' preface - Wood Tools

observed features can be carried out on the
cross-section with various instrumentation,
such as energy dispersive X-ray spectrometry
or electron microprobe, if connected to a
scanning electron microscope.
X-ray images of metal objects can provide
information concerning methods of manufacture.
For example, cast metal may contain
voids or other casting flaws, which appear in
radiographs as dark spots, while hammered
objects sometimes exhibit a characteristic
mottled hammer blow pattern. Repairs and
replacements are often detectable with X-ray
radiography, for example solder is often recognizable
due to its porous structure, characteristic
flowed appearance and radio-opacity.
However, where the solder and bulk metal
have similar densities the solder join may not
be detectable in radiographs. Computer aided
tomography (CAT) might prove helpful in
such instances because it detects very small
density variations.
In contrast to the wide range of analyses
which have been carried out on works of art
in metal, the identification of materials and
manufacture of metal components on furniture
have thus far received little attention. The
results of most studies are unpublished, only
briefly mentioned (Koller, 1989; Pelz, 1992)
or included in footnotes (Brachert, 1986;
Schneider, 1990). Studies to determine the
origin of several south German boulle works
based on the elemental compositions of their
pewter and brass inlays have been carried out
by Walch (1993) and Segebade (1993, 1994)
using photon activation analysis. X-ray fluorescence
was used to establish that what was
thought to be a gilded surface on brass casters
from a nineteenth century American couch did
not in fact contain gold (Thomson, 1991).
Dating metals
Marks stamped on to metals may relate to the
particular maker(s), may be characteristic of
certain regions, such as the Augsburg pine
cone (Kisluk-Grosheide, 1991; Stratmann,
1975), or may relate to taxation, such as the
crowned C mark on French bronze mounts
(de Bellaigue, 1974). Such marks may aid in
dating because they often reflect documented
changes in guild and state regulations.
With the exception of experimental methods
for carbon-14 dating of iron (Creswell, 1992;
Other materials and structures 213
Riederer, 1981) there are no instrumental
methods for determining the age of metal. At
least until the Industrial Revolution, when
geological coal or coke were introduced as
fuel, the carbon incorporated into iron is
generally contemporaneous with the manufacture
of the object itself. The fact that previously
produced iron goods were recycled is a
potential source of error and must be taken
into consideration. Dating of historic metal can
be based on comparison to documented
inventions and discoveries affecting metallurgical
practices. Metallographic examinations
have, for example, been carried out on the
metal components of a historic wooden gate
in order to determine its age (Storch, 1987).
5.6 Ceramics and glass
Ceramics, clay products made permanent by
heat, are among the most ancient of human
technologies. Vitreous glazes on ceramics
predate the use of glass as a separate material.
Glass vessels made their first appearance
in the Middle East and Egypt around 1500 BC.
Beautiful and functional ceramics and glass
have been the object of increasingly complex
technologies since their earliest use and
occupy a central place in human technological
history (see Kingery, 1986; Singer, 1958).
The carbide cutting teeth on the best modern
woodworking tools are a form of metallic
ceramic made from carbon and various metals.
Ceramics are commonly found in furniture
as tiles or decorative knobs and escutcheon
plates. Knobs and pulls have also been made
of glass, particularly after the development of
pressed glass in the 1840s made cheaper imitations
of cut glass widely available. Glass may
also occur in furniture in the form of clear or
coloured flat-glass glazing in case pieces, or as
mirrored glass. Glass mosaics produced in
Rome during the eighteenth and nineteenth
centuries were used as decorative inserts or
entire table tops. The Roman Mosaic technique
employed a wide colour palette of thin glass
rods (smalti) set closely together on end to
create extremely detailed images. Glass has
also been important as an abrasive (glass
powder glued to paper) in woodworking.
Glass can be described as a meta-stable
super-cooled liquid because as it cools from