Fire is a constant hazard
in libraries, and most collections of historic manuscripts have some burnt
parchment. Certainly the British Library has its share, including parts of the
Most older manuscripts were written on parchment which, being animal
skin, does not respond to heat and water like paper but becomes crisp and wavy,
looking somewhat like a poppadom. When a manuscript reaches this stage, there
is little conservators can do except house it carefully.
Royal MS 9 C X. One Royal manuscript has deliberately been left
unconserved since the Ashburnham House fire (1731) to show the damage done to the collections
Fortunately, our ancestors
knew how to preserve books. Many
medieval manuscripts were originally bound in thick oak boards with clasps. When
it became customary to store books upright, they were packed close on hardwood
shelves. In these conditions, air
circulation is limited (denying oxygen to the fire) and the dense materials
diffuse heat. Surface charring inhibits the release of volatile gases, delaying
combustion. Today we also rely on low
oxygen systems to prevent fires.
Cotton Fragments XXXII. Boxes of fragments remain from the 1731 fire; some
attributable to specific manuscripts, others found loose in the containers that
held the damaged manuscripts.
If parchment has been well
made, most of the fats will have been removed from the skin by scraping,
leaving a dense mat of collagen fibres which are then stretched flat to dry.
When heated, collagen shows little change at first; then the fibres contract
swiftly and irreversibly over a small temperature range of just a degree or two
(called the shrinkage temperature).
Additional MS 22750. Parchment leaf inlaid in paper. The contrast between the apparently undamaged
area and the severely degraded part is very clear, showing the boundary of
As fire takes hold in a
library, a temperature gradient builds across the text-blocks, the centres
remaining cooler. This explains the typical pattern of a leaf from a burnt
book, the edges shrunken but the centre merely cockled (a response to uneven
stresses, like gathering the edges of a piece of fabric). The transition marks
the point at which the shrinkage temperature was reached
Tiberius D V. The text suddenly gets smaller, showing that the
parchment has shrunk. The cuts were made
during early repairs, so that the leaf could be flattened.
At the leaf edges, which
are most exposed to heat, the collagen can be denatured to gelatine, becoming hard
and brittle and sometimes forming a glassy exudation which seals the
Cotton Otho A XIII. Gelatinised parchment. The strips holding the fragment have caused
staining and cover part of the text.
Of course, water was used
to extinguish historic fires and this causes further damage to parchment. Too much moisture causes reversion to the
memory of being animal skin and, unless it is dried under tension again, the
parchment swells and cockles. Many
books, undamaged by heat, were air-dried after the fire and show this kind of
damage. Those that were not dried
quickly enough may also be weakened and stained by mould.
Cotton Julius A II. This manuscript has only slight water damage (and
possibly not from the fire), though there are indications that the margins were
trimmed before rebinding. This was
sometimes a “quick fix” to remove blackened edges where text was not
Early treatment was simply
to soak the parchment in water to make it flexible and then stretch and press
it. The heat-contracted edges which
would not expand were often slashed between lines of text to allow flattening. Sir Humphry Davy (d. 1829) improved on this by
suggesting a mixture of “spirits of wine” (alcohol) and water, and such
azeotropic mixtures continued in use till very recently, as they allow a
controlled application of moisture to rehydrate dry parchment. However, even
this is now thought damaging, and cockled parchment will just be allowed to
relax in a slightly humid atmosphere, before pressing. Other experiments to try to make the texts
more readable have added to the parchment’s degradation.
Cotton Tiberius E VI. An extreme example of cutting into a fragment of a
Cotton manuscript in order to flatten it so it could be inlaid. It is also possible to see that the paper
frame is starting to cockle as stresses readjust in the parchment fragment.
Typical fire damage leaves
the text in the centre of the page readable, but the weak edges are easily
broken by handling and it is imperative to protect them to prevent fragments
becoming detached. It is estimated that
the Beowulf text (Cotton Vitellius A XV) lost some 3000 letters before
1817. It and many other manuscripts were
eventually treated by inlaying each leaf in paper, but the strips used to
secure the parchment themselves covered more text. The adhesive seems to have been paste, which
left stains and is now becoming brittle; the paper frames are degrading too,
and often cockling under the pull of the parchment. Other early repair
techniques used parchment infills, silk gauze or goldbeater’s skin.
Egerton 2745, f. 165r. Lamination is holding the fragments together and
maintaining the relationship of the lines of text, but making it difficult to
read. Retreatment is not an option
because removing the laminate would cause further damage and the leaf is
These methods helped to
preserve the fire-damaged manuscripts, but the materials used are now
aging. We have become much more cautious
when treating parchment since realising that it may be far more degraded than
it looks. Moisture can cause gelatinisation; too strong repair materials can
pull on and split the weaker skin, adhesives must remain flexible. No wonder
that our current emphasis is on sympathetic housing, to slow deterioration and
give support to damaged leaves without the dangers of re-treatment.
Cotton Otho A XII. An extremely damaged fragment, now housed in a
We are fortunate that
fire-damaged parchment manuscripts can now be made available to readers through
digitisation, avoiding the risks of further handling. Safe in controlled conditions, we are
confident that even after heat, water and incautious early treatments, they
will long survive.
Ann Tomalak, Conservation Officer, The British Library