The Conservation of the 18th Century Sloan-Osborne Ciphering Book

[This blog post was written by Garrett Sumner, a graduate student at West Dean College and summer intern in the Conservation Lab]

As part of my internship at the Conservation Lab in the State Archives of North Carolina, I had the opportunity to work on a number of projects, but the one object that garnered most of my time was the Sloan-Osborne Ciphering Book (PC.1955). The Sloan-Osborne Ciphering Book is actually two distinct notebooks, one from the 1750s, and the other from the early 1780s, which were later sewn together. The notebooks contain numerous ciphering problems, such as long division and unit conversion, and were composed by two individuals, Adlai Osborne and Henry Sloan. While their exact relationship to one another is unclear, Sloan may have served as Osborne’s pupil at Charlotte’s Liberty Hall Academy, where Osborne may have given Sloan his notebook. The most intriguing aspect of the book is that it contains two partial snake skins that are still adhered to the paper. Most likely the book was stored in an attic or basement and one or more snakes slithered between the papers to shed their skin.

The book arrived in the conservation lab in a very poor condition, preventing its use by researchers. The paper was very brittle and cockled, and had suffered extensive water and pest damage. Furthermore, some pages were missing, removed either intentionally or accidentally. The iron gall ink used to write the notebook was fading, and in some areas had even burned through the paper.


Example of iron gall ink burn and damage to paper.

In conservation practice we aim to follow two principles when treating an object: minimal intervention (doing as little as is needed), and reversibility (that any treatment performed can be reversed). However, when an object is so extensively damaged it cannot be safely handled, a more aggressive treatment may be necessary to stabilize it. Such was the case with the Ciphering Book.

The treatment plan for the book involved removing the original sewing thread to allow the paper to be washed. Because iron gall ink can be water-soluble, we first had to perform solubility tests by placing droplets of water, ethanol, or a mixture of the two in different areas to see if the ink migrated. The tests showed that some ink was water soluble, and so to err on the side of caution we used a solution of 50/50 water and ethanol for the bath. Although washing paper is a risky, non-reversible procedure, it can also remove dirt, discoloration, and the acidity that makes the brittle, as well as flattening out the folds and cockling in the paper.

The sheets were gently placed in the bath for 25 minutes. The paper was so dirty we could actually see the discoloration floating out of the paper. After washing, the sheets were then placed between felts to dry. A less invasive washing method was needed for the snakeskin pages. Instead of immersing the sheets in a bath, we placed them between sheets of blotting paper saturated with the 50/50 solution, along with a hole cut out in the areas around the snakeskin in order to not disturb them.

After drying, the paper was noticeably cleaner and flatter, and some of the writing was more legible as a result of the increased contrast between the ink and the now-cleaner paper. However, washing left the paper a bit weak and limp, so the paper was re-sized with a 0.5% gelatin solution. Paper was traditionally sized with gelatin, a type of animal-based adhesive, which would fill in the gaps of air between the paper fibers to give the paper more strength and protect it.

After more drying, the paper was ready to be mended. There were countless tears and holes on every sheet, in all shapes and sizes. When mending paper, conservators typically prefer to use Japanese tissue and wheat starch paste. Japanese tissue is thin yet strong, with long fibers that allow it to easily blend into the original paper. Wheat starch paste is a refined paste made by hand using just starch and water. Together, these form a strong repair that can be reversed in the future with water, if needed. To mend the tears and holes, pieces of Japanese tissue were carefully torn to the appropriate shape, then brushed with paste and applied to paper.

Twenty-five hours later, the mending was complete, and the repaired book was ready to be resewn. Replicating the original sewing pattern would have been difficult and potentially damaging, so instead the book was sewn through five new holes using linen thread. A paper wrapper was sewn on the outside of the book in order to provide more protection. In all, the treatment took 49 hours to complete. After treatment, the book is now much cleaner and can be safely handled by researchers, snakeskins and all.

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I would like to thank the NC Department of Natural and Cultural Resources for facilitating this internship and for providing guidance and assistance during its course, especially Dr. Kevin Cherry, Emily Rainwater, Kate Vukovich, and Mathew Waehner.

The Sloan-Osborne ciphering book is now available as part of our North Carolina Digital Collections!


2 thoughts on “The Conservation of the 18th Century Sloan-Osborne Ciphering Book

  1. Donna Jones

    What a fascinating account of the restoration process. It must have been an amazing internship. What a treasure to be able to digitize this and make it available on the North Carolina Digital Collections website.

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