Vom Grönlandwal zum Grabdenkmal: Probleme der Konservierung von Unterkieferhälften des Balaena mysticetus, verwendet als Grabdenkmäler auf Vlieland

Abstract

In the seventeenth and eighteenth centuries the inhabitants of the West Frisian island of Vlieland participated in Arctic whaling ventures. Due to the poverty of the society on this mud-flat island, the jawbones - from which the oil was extracted on the return voyage - were not considered virtually worthless and used as mere building material or the like, but placed on graves as markers or gravestones. They now form part of the island’s cultural-historical wealth, for they are the only objects of their kind. In order to preserve these testimonies to Vlieland’s cultural heritage, six of the seven jawbones were moved to the island church in 1920, where they were presumed to be safe from wind and weather. It became apparent, however, that variations in humidity in the church's interior as well as temperature variations and fluctuations were causing harmful shrinkage and expansion processes in different bone parts. Not only were the necessary conservation measures carried out, but the presentation conditions were improved in such a way that the jawbones are now subjected to the most constant possible levels of humidity and temperature. The impregnation of the jawbones proved particularly problematic, for none of the available substances fulfils the requirement of reversibility without negative accompaniments. Thus the choice had to be made between an irreversible means of conservation and merely waiting as the process of the peeling or scaling off of the majestic backs of the bones continued - at a decelerated rate, to be sure, but nevertheless steadily. In the case discussed here, a special epoxy resin - OMV-E - was applied, a substance that does not smell unpleasant, is not shiny, hardly causes discoloration and penetrates the surface of the bone deeply enough before hardening to put an end to the peeling process.