Series editors' preface - Wood Tools

244 Conservation of Furniture
affecting the use of objects. It may therefore
be helpful for the conservator to spend some
time to understand the points of view of
others involved in the cycle of management of
collections and be prepared to offer solutions
to conservation problems that meet the needs
of a wider group of stakeholders. Such consideration
for the points of view of others is
usually repaid.
Discussions of aspects of the function,
organization and planning of museums which
may be generally helpful are offered by the
Department of National Heritage (1996),
Ambrose and Paine (1993), Ambrose and
Runyard (1991), George and Sherrell-Leo
(1987), Knell (1994) and Thompson (1984). A
useful summary framework for the preservation
of institutional collections is provided by
the Canadian Conservation Institute (1994).
Bachmann (1992) deals with conservation
concerns and Keene (1996) with the management
of conservation in museums.
6.2 The environment
The condition of furniture and wooden objects
depends on the materials from which they are
made, on their structures and on the conditions
to which they have been exposed during
their lifetime. The materials may be organic
(wood, textiles) or inorganic (metals, ceramics,
glass), with the former generally considered to
be more susceptible to deterioration. No
material, however, is stable under all conditions.
This raises problems for mixed collections,
especially where materials requiring
different conditions for their preservation are
found in the same object or need otherwise
be shown together. Deterioration of furniture
items can proceed through physical, chemical,
or biological agents but generally more than
one force is in operation at the same time. In
discussing what can be done to minimize
damage, it is useful to find some underlying
basis for the description of the processes of
decay. This is possible to a certain extent
through an understanding of the thermodynamic
and kinetic molecular theories of
chemical change. The second law of thermodynamics,
which tells us that nature is gradually
moving towards a state of disorder, gives
little comfort. We can, though, do something
to slow down the rate at which this affects our
objects. Some points concerning chemical
reactions in general will therefore be discussed
first as a basis for understanding the influence
of light, heat and humidity, discussion of
which follows.
6.2.1 Background chemistry
Systems tend to move towards their most
stable state. We might therefore expect that
the more stable the products of a reaction are
compared with the starting materials, the
further towards the products any equilibrium
between them might lie. In seeking their most
stable condition, systems tend towards
minimum energy (enthalpy – H) and
maximum disorder or randomness (entropy –
S). A measure of their relative stability thus
embraces H and S and is provided by the
Gibb’s free energy (G). The free energy
change during a reaction at a particular
temperature is given by the following
equation:
G = H – TS
where
is used as a symbol to represent the
amount of change
G is Gibb’s free energy
H is minimum energy (or enthalpy)
T is the absolute temperature (0° absolute
equals –273 °Kelvin)
S is maximum disorder (or entropy).
Whether or not a reaction will proceed spontaneously
depends on the free energy change
(G) for the reaction. For a spontaneous
reaction to occur G must be negative, that is
the free energy of the products of the reaction
must be lower than the free energy of the
reactants. The more negative the value of G
the further will the equilibrium for a reaction
lie in favour of the products. G is related to
the equilibrium constant for the change by the
relation
–G = 2.303RT log 10 K
where R is the Gas Constant and T is the
absolute temperature. Knowledge of the