Re-housing the NMINH Irish and British marine molluscs collection
Please find below the final report for Heritage Grant–
Re-housing the National Collection of Irish and British Marine Molluscs.
There are two files: the final report, in this file <molluscs_report.doc> and the catalogue appendix <mollusc_appendix.pdf>
Work on this project is now complete. Funding is now requested for remuneration for coverage of the project costs of archival supplies, for the agreed award—
payment has already been recived for the consultancy portion of the award, for € 3220
the remainder, for costs of archival supplies is € 2780.
(The total amount of the award was € 6000).
n.b. Funding for equipment and supplies were provided by UCD Zoology departmental research funds, and the National Museum of Ireland.
Please see the budget (below) for detailed costings.
As these costs were incurred by the UCD Zoology Department in partnership with the NMINH, please make the cheque payable to UCD ZOOLOGY, care of Julia Sigwart. If you need any additional information, please contact me.
Yours sincerely,
Julia Sigwart
Re-housing the Irish and British Marine Molluscs collection
in the National Museum of Ireland (Natural History Division)
Final Report
Prepared by: Julia D. Sigwart
Introduction ...... 2
Methods ...... 3
Findings ...... 6
- Bynes disease and glass disease
- Impact for heritage
- Value for natural heritage
Conclusions: Strategic Plan ...... 12
Appendix – Catalogue of the collection ...... 14
Introduction
Since project launch in March 2004, we have followed the re-housing procedure as outlined in our initial proposal for funding. We can report a wealth of new information regarding the condition and status of the Irish and British Marine Molluscs collection in the National Museum of Ireland.
This project has resulted in the cataloguing and re-housing of over 3,300 museum specimen ‘lots’, including more than 14,000 individual molluscs (see Figure 1). A lot is defined by a group of objects that are environmentally related to each other – a group of animals, all of the same species, collected together in the same time and place. In this collection, a lot can include from one (1) to, in rare cases, more than 30 individual specimens. Usually lots contain two to three individuals, intended to give a rounded biological example of how the animal looks in nature. Larger lots tend to be correlated with smaller, more abundant shells such as Rissoiid snails (tiny snails only a few millimetres in diameter).
The collection includes more than 1400 bivalve molluscs (clams, oysters, and allies) and more than 1700 gastropod molluscs (snails and allies) as well as more than 200 examples of other, more rare groups such as tusk-shells (see Box 1). These range in age from specimens donated definitively in 1835 to the present day. It is possible that some elements in the collection could be older than 170 years, as the original collections acquired by the Royal Dublin Society did contain ‘seashells’ or mollusc specimens, but there does not appear to be documentation for any of these specimens that had Irish or British origins.
The collection is now stable, in safer appropriate housing which will ensure the good long term care of the whole collection. However, the continued investigation of this collection has uncovered not only undiscovered hidden value in both historic and scientific contexts, but has also helped define the path for future work that is needed to protect and enhance this aspect of Irish heritage held in trust by the Natural History Division.
Methods
Before work could proceed on the documentation and housing improvements planned for this historical collection of marine molluscs, the first step was to move the entire collection into the Natural History Division’s collections storage and research facility. In addition to gallery space in Merrion Street, Dublin 2, where these specimens had been held since 1868, the NMINH also holds a dedicated store facility in Beggars Bush (Dublin 4). The historical cabinets that had previously housed this collection of Irish and British marine shells were over-crowded and for any creating conditions that prevented safe access and use of the collection. For practical reasons, a decision was taken to move the specimens in situ to their new facility in Beggars Bush. Each drawer, packed full of boxed specimens, was individually removed from the historical cabinetry, padded, wrapped, and packaged for the move across town. A total of twenty-two (22) drawers of marine shells were packed and moved in this way. The collection was then moved by private car for the short trip across town. The drawers were laid out in the Beggars Bush facility and unpacked as work progressed on assessment and documentation. This technique resulted in efficient and effective work on the documentation procedure, with no superfluous handling, and successfully resulted in moving a delicate collection with no damage whatsoever to the specimens.
With the specimens in their new home, each old drawer was unpacked and processed on an individual basis. The drawers were unwrapped, and packaging material removed and discarded. The following four-step procedure was used for each specimen, as outlined in the plan presented for this project.
1. Assess old housing / boxes
When application was first made to the Heritage Council to fund this project, we were already aware of the poor state of the original housing of these objects. Housing directly impacts not only the safe handling of objects, but also their conservation status as improper materials can cause direct chemical environmental damage to shell collections. Historically, specimens were kept in matchboxes; some objects were kept in highly acidic glass-topped display boxes. These are not only a problem in terms of acid degradation of the objects, but also in a context of safe handling—the inlaid glass tops had become brittle and often shattered with even minimal handling, leaving shards of glass mixed with shell. Smaller specimens had been kept in traditional soda-glass vials stuffed with organic cotton wool. This is again a two-fold problem, as soda glass degrades through ‘glass disease’ (see Findings, below) and with a specimen chamber plugged by acidic, organic cotton; the object environment is therefore damp (through ‘weeping’ of advanced stages of glass disease) and in an acidic atmosphere. This is probably the worst possible environment for shell specimens.
In more recent times, however, (circa mid-1990s) many specimens had been moved into small zip-closure plastic bags. For larger specimens this is somewhat better in a context of specimen environment than matchboxes, but smaller specimens were still contained in glass vials within the plastic bags, which did not have much impact on the actual specimen environment. The handling implications of these bags generally proved disastrous. Before this project undertook to re-locate this collection, specimens were piled several layers deep in the drawers, where the artefact bags were physically prone to slide over each other. We have found several specimens that have been damaged because they were in an overcrowded drawer of plastic baggies, and slipped behind the drawer and were crushed.
2. Survey status of historical labels
Many specimens include labels that indicate that many older parts of the collection were studied and identified by important marine scientists such as John Gwyn Jeffreys, who was an acquaintance of Charles Darwin (see Findings, below). Very often there will be a set of two or more labels contained with a specimen lot: one with the scientific name and the collecting locality, a second, separate label identifying the original collection, and sometimes a third label with additional or redundant information. These labels are variously hand-written or typed, throughout all ages of specimens. Typically the labels identifying a collections (e.g. ‘Warren Collection’, see Appendix) are typed and were clearly created in bulk sheets and then cut and distributed into all boxes belonging to a certain donor. Whether this was done by the donors for their own purposes prior to accession, or if the labels directly reflect the specimens’ incorporation into the larger Museum shell collection it is not possible to determine.
Many smaller specimens were found to be stored on ‘presentation’ papers or cards, mounted with animal glues on a label that included details of the species name and the donor. These specimens are often tiny, in the range of several millimetres in length. Interestingly, the presentation labels often include information about the individual that had prepared them for display (arranging, fixing, and labelling on card) and this was obviously considered a feat of great skill, and with good reason for such tiny and delicate objects. Often for these very tiny shells, a set of five or six individuals is laid in a series, all with identical orientation. The arrangements are always geometrically symmetrical, so it is very easy to identify cases were one or more has been removed or lost. At this point, we consider these cards, although not archival by any means, to be the best means for continued storage. The specimens have often dropped spontaneously from the cards due to the degradation of the animal glues used to affix them, but due to the individual shells’ tiny size and their fragile nature, they seem to be much safer when associated with the cards. No attempt has been made to re-affix them, nor have we attempted to remove additional specimens from their cards. This may be reassessed in future.
3. Survey object condition (check for degradation, breakage, etc.)
As mentioned above, the impacts of poor housing on individual specimen conditions were already understood to be problematical when work on this project began. However, object conditions were generally found to be in better condition than expected in this collection, especially compared to known degradation (due to Bynes disease) in the other (i.e. ‘foreign’) shells. Specimens kept in soda-glass vials have been less prone to Bynes disease, previously thought to be an extensive problem in this area of the collection, but often prone to ‘glass disease’ as the vials degrade. Many shells with fine projections were found to be encumbered by the cotton wool used as padding or to plug vials. The cotton was often discoloured to brown. Other specimens, particularly those fixed with animal glues (as mentioned in step 2, above) seemed to have been affected by a fungal infestation, although there was no apparent present live mould or fungal growth remaining. No effort has been made to clean the residues of foreign material, either cotton wool or fungal residue. This should be approached as a further project in the near future.
4. Transfer specimen to new archival housing and individual boxes
The entire collection has been removed from the gallery building in Merrion Street and transferred to the Museum collections storage building in Beggars Bush. Each specimen was individually re-examined as described above, and transferred into new high-density press-wood drawers in a dedicated mollusc collection room within the Beggars Bush building. The collection has been given considerable room to expand—the footprint of drawer surface area containing the collection has increased by twofold. This is both safer housing for specimens in terms of environment and handling. Paired with item-level documentation for the collection (see Appendix), the new state of housing allows for easy access of any particular item in the collection, for the first time in over a century!
Findings
Glass Disease & Bynes Disease
Glass disease results directly from the chemical composition of soda glass (glass made with low amount of lime in high heat), and the chemical reaction with normal atmosphere. Glass itself is an amorphous matrix of silicate anions (negatively charged) and metal cations (positively charged). The main ingredient is silica (SiO2), to which alkaline substances such as potash (K2CO3) or soda ash (Na2CO3) are added as ‘fluxes’, together with lime (CaO) or magnesium oxide (MgO) as stabilisers.
The first step, known as alkali depletion, occurs when soda glass is kept in a very humid environment. Alkali ions contributed by the ‘flux’ materials migrate to the surface of the glass matrix, where they are replaced with the hydrogen ions from water vapour (readily available in this humid environment). The resulting alkali-deficient, hydrogen-rich ‘gel’ layer has a dull appearance. The process forms potassium and sodium hydroxides that react with carbon dioxide and sulphur dioxide from the air, and form hygroscopic salts. These salts in turn appear as a layer of greasy, highly corrosive film on top of the depleted glass—that is, it makes its own dirt. (In extreme cases, this can be followed by a second phase leading to the fracturing and eventually total disintegration of the glass.)
The progress of the chemical reactions of glass disease with water vapour can cause droplets form on the surface of the glass, a phenomenon known as ‘weeping’. When glass affected by glass disease is removed into an environment with a relatively lower humidity, the sodium and potassium carbonates form a white precipitate on the surface, which in the case of mollusc collection can be confused in appearance with Bynes disease.
Although there is genuine cases of extreme Bynes disease in other aspects of the NMI molluscs collections, it appears that previously anticipated problems are less dangerous in this collection. Glass disease has no permanently damaging effect on the molluscs within glass vials effected by this chemical decay, and the problem of precipitating dirt and salts can be corrected though re-housing into more stable glass vials.