Strain in wool

New Scientist (8th July 1995) includes news on research being carried
out by David Howell, Conservation Scientist at Historic Royal Palaces
Agency and David Armitage of the National Physical Laboratory at
Teddington, England. Over the last seven months the two have
monitored, using strain gauges minute by minute, a 42 kilogram woollen
Tudor tapestry hanging at Hampton Court.

Like many artifacts on display the tapestry is subject to
fluctuations in humidity from day to day weather changes and the
daily trekking by of visitors.

Earlier research by the textile industry had surprisingly shown that
wool can absorb up to 40% of its own weight. Howell & Armitage have
however already found that items may not absorb as much as first
thought, their research has shown that the moisture content of the
tapestry changes quickly and that the weight of the tapestry has
changed by less than 1%.

This may have important implications for museums and stately homes
that spend vast sums to regulate air conditioning and humidity
around their artifacts.

Mark G. Vine
Conservation Resources, England

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                   Conservation DistList Instance 9:7
                   Distributed: Monday, July 10, 1995
                        Message Id: cdl-9-7-005
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