: Collectors & Collections

Figure 1 Image of a section of a specimen sheet belonging to the 3rd Earl of Bute’s herbarium c. 1770. The paper sheet is not providing any clues as to whether this sheet has been treated or not. The brown stains are natural breakdown products of the plant.

Figure 2 The same herbarium sheet under UV exposure. The grey discolouration is typical of mercury and the bright splashes are indicative of aqueous mercury applications.

Figure 3 Using the UV scanning device.

Natural history collections are susceptible to deterioration from pests and moulds and so historically, chemicals have been applied to safeguard these collections for the future. The most common chemical application to botanical specimens was Mercuric chloride (Corrosive sublimate). Mercury has helped to preserve specimens up until the present day, but these treatments leave a legacy - salts of mercury are not only toxic to pests, but also to people.

'Mad as a hatter'

In the 19th century, the felt-hat industry commonly used mercuric nitrate to cure the felt. The wearer and the hat maker were then exposed to mercury which is now known to attack the central nervous system and affect the brain. The unusual behaviour attributed to hat makers, due to the mercury poisoning, gave rise to the term ‘Mad as a hatter’ and probably fuelled Lewis Carroll’s imagination for his ‘mad tea party.’

The main problem encountered with these treatments is that they are hazardous to health but largely imperceptible to the human eye (Fig. 1).

Research conducted at the National Museum Wales department of Conservation, uncovered that some of the 600,000 herbarium specimens housed within the collections were contaminated with mercury. This could pose a potential risk to the health of staff members and visitors to the collections, unless addressed. It was important to be able to establish which sheets had been treated, what the chemical was and how much was present. To do this in the usual way would have involved specialist chemists, expensive analytical equipment and years of work; an expensive and timely process.

Continuing research into this issue by Dr Vicky Purewal, the botanical conservator at the National Museum Wales, uncovered that chemical processes are accelerated by mercury in the ageing papers, providing tiny clues to the presence of mercury. By devising a specific novel technique, these tiny clues can be translated into real information. This technique does not require expensive analytical equipment, all it needs is a simple hand held UV-A lamp. The Ultra violet radiation causes certain chemical processes in the paper to fluoresce a definite colour providing a positive response to the presence of mercury (Fig.2).

This research by the museum has been vital in developing a rapid technique in identifying contaminated collections (Fig.3). It has helped provide information on the historic treatments that the specimen has undergone and as a result helped to safeguard the health of staff members and visitors to the herbarium. As a result the collections can be separated into treated and non-treated material. The contaminated collections can then be handled appropriately and re-mounted removing a large amount of the contamination from the herbarium environment. DNA analysis currently carried out by researchers within the NMW herbarium; also find the UV technique extremely efficient at helping to determine whether the collections have been subjected to mercury applications which may interfere with extraction of genetic information.

The impact of this research is two-fold: on professional conservation and curatorial practice; and on the health and safety of the collection users when working within the herbarium. Key institutions such as the Royal Botanic Gardens, Kew, the Natural History Museum, London and the Royal College of Physicians are just a few of the other organisations that have benefitted from this simple and rapid identification tool developed by Vicky Purewal at the National Museum Wales.

Portrait of the Third Earl of Bute (reproduced from Temple of Flora (1807) by Robert Thornton).

The museum’s copy of Bute’s Botanical Tables.

2013 was the birth tercentenary of the Third Earl of Bute, a powerful figure in eighteenth century Britain – renowned both as a politician and as a botanist. One of his greatest contributions to botany was a book called the Botanical Tables, and Amgueddfa Cymru is fortunate to own a complete set of this rare and exquisite publication.

John Stuart, 3rd Earl of Bute (1713-1792) was a friend and confidante of George III. Early in his career Bute reluctantly became a politician, encouraged by his royal friend. In May 1762, he was appointed Prime Minister. However, Bute proved an unpopular leader and resigned after a year. He must have been relieved to retire from public life to his house at Highcliffe in Hampshire, with his vast botanical library, to continue his botanical interests.

Carl Linnaeus's new taxonomic system

Bute worked on several botanical publications and was strongly influenced by the renowned Swedish taxonomist Carl Linnaeus. Bute's best known publication was entitled Botanical Tables, or to give it its full title; Botanical Tables containing the different familys of British Plants distinguished by a few obvious parts of Fructification rang'd in a Synoptical method. Published in 1785, the aim of the Tables was to explain the principles of Linnaeus's new and controversial taxonomic system.

Most of the illustrations in the Botanical Tables were by the artist John Miller (1715-1790). It was a huge task, involving over 600 illustrations detailing the sexual organs and their number to comply with the Linnaean system. Each set of Tables consists of 9 volumes covering the whole range of British plant life - including mosses, grasses, flowers and trees, as well as lichens, fungi and seaweeds - and contains detailed illustrations of every plant listed.

Twelve sets of the Tables were printed by Lord Bute at his own expense, at a total cost of £1,000. Most sets were bound in speckled fawn calf leather with the Bute coat of arms placed centrally. Two sets were specially prepared for the royal family and bound in red goatskin with pages edged in gold but without the Bute arms.

Botany as a fashionable amusement

Bute was particularly keen to explain the taxonomic system to women, since he felt that this "delightful part of nature" was peculiarly suited to the attention of the "fair sex"; botany, under their protection, would soon become a fashionable amusement. True to this aim Bute presented seven sets of the Tables to women:

Amgueddfa Cymru has in its collections loose illustrations and tables that are thought either to have been draft copies or material being prepared for a subsequent edition. However, in 1994 the Museum acquired a complete copy of the Botanical Tables at a Christie's sale of highly important books from Beriah Botfield's Library.

Whilst trying to ascertain which of the original 12 sets the Museum holds, researchers here have managed to trace 10 sets, 7 of which can be identified with their original recipients.

Perhaps, one day, the remaining two will be discovered on a dusty shelf of an old library and then all twelve original copies can be accounted for.

Recipients

The recipients of the twelve copies of the Botanic Tables: