Every year we conserve approximately 2,200 items, taking hours of skilled work, but there are many more items in need of repair. As the Library’s collection continues to grow and age, so do the number of items that need our attention.

In this post, book conservator Zoe Miller describes the work carried out to conserve Sloane Manuscript 1006, Astronomical Scheme after Henricus Khunrath.

This unusual and unique late 17th century manuscript came to conservation in a very poor condition. It was thought to have been produced by Dr Heinrich Khunrath (1560-1605), a physician, hermetic philosopher and alchemist who travelled Europe working as a court physician. He met John Dee, one of several alchemists who heavily influenced his famous work Amphitheatrum Sapientiae Aeternae [The Amphitheatre of Eternal Wisdom].

The binding, with its covering of sprinkled calf skin with green paper had broken, much of the original leather and paper covering had worn away and the spine and sewing were split in many places. It was foxed (a form of age-related chemical degradation of paper which causes reddish-brown spots) with ingrained surface dirt and many folds and stresses to the contents through inappropriate handling.

Much of the damage is a result of its physical uniqueness. The text block consists of heavy weight single folios sewn on cords, onto which are stitched 181 paper objects with hand drawn geometrical diagrams and deconstructions of an astronomical model.

These paper objects—often annotated in iron gall ink—have been carefully arranged on each folio and freely hang from the page as it is turned, posing a significant risk during handling and consultation.

Very little detail was known about the provenance of this volume, its creator, or the scholarly importance of the curious contents. This posed a problem. With all objects I am responsible for conserving, I aim to build a detailed conservation treatment proposal from an understanding of the cultural, historical and intellectual context of an object and its past use and ownership. This is to ensure that important historical evidence is preserved and that its scholarly value is not inadvertently diminished.

Working together with collection specialists we arranged to meet a previous reader of this book, a university professor whose expertise could help us make informed decisions for treatment. As the conservator, I was able to add to the body of knowledge of this item through my physical examination of the materials and processes used to construct the book and by contributing my understanding of patterns of deterioration and damage.

As a result of this interesting discussion it was decided to digitise the manuscript in order to preserve the exact state and positioning of the contents for scholarly study. This also will allow us to restrict access to the original in order to preserve it.

In preparation for digitisation, the manuscript was cleaned and dis-bound, removing broken threads and degraded binding materials which were causing further vulnerability.

Surface cleaning showing before and after cleaning

The astronomical objects were then stabilised using repair techniques which respected delicate inks and pigments to enable high quality images to be taken.

Following digitisation, the volume was returned to the Centre for Conservation to undergo further treatment. After recreating the original sewing structure the book boards were consolidated to prevent further loss of fragile materials and reattached to the text block.

Resewing the volume.

A flexible, low adhesive method was chosen to repair the spine using layers of Japanese tissue and wheat starch paste to recreate the original appearance of the binding as a tight-back (where the spine covering is adhered directly to the spine folds and sewing supports) while in reality creating a hollow-back, which serves to protect both the spine folds and the original spine labels which were adhered to the new covering leather.

Finally the delicate remnants of gold finishing from the degraded leather spine, which had been carefully removed before treatment, were encapsulated, to be stored with the volume for future consultation. Wherever possible we will aim to keep valuable evidence of a previous binding if it cannot be re-used.

Before and after conservation.

Treatment of this unique object has not only stabilised it physically for future generations but through digitisation we have been able to make its contents available to scholars within this niche area of study. Conservation has enabled and contributed to a growing body of knowledge on this manuscript.

Zoe Miller

Every item that comes into the Centre for Conservation receives this kind of care and attention, because to us every item is a treasure in its own way. It’s our high standards and level of expertise that means conserving items is a timely process and we will not compromise on the quality of the work that we do.

Your can play your part in preserving our heritage by making sure we have the resource to play ours, together we can make it last for generations to come.

Donate online by visiting: www.support.bl.uk/conservation