A guest blog by Conservator, Monika Stokowiec.
It was a very exciting opportunity to work on a book which belonged to Isaac Newton and not something many book conservators have chance to do in their professional careers. At first sight the book did not seem in too bad a condition as the binding has been fairly well preserved apart from a piece of leather missing at the top. Unfortunately, once opened the extent of the damage was quickly obvious. The text block was severely damaged by insects, with tunnels painstakingly chewed throughout the thickness of the book at the head and tail (the top and bottom of a book), within the spine area and around the top corners. Page after page was affected to some extent by the insect damage.
The main suspect was the common furniture beetle (Anobium punctatum) or a couple of other beetles from the Anobiid beetle family. The beetle lays an egg on the book and then the larva chews tunnels in the book feeding on the starch or any proteins from the gelatine in the paper until the larva develops into a beetle which can take between 2-3 years!
Apart from the damage to the paper, the sewing structure was also affected and the book was falling more and more apart with every attempt to open it. Furthermore, the binding seemed quite tight and the broken structure did not want to go easily back into the binding. Part of the leather on the spine was missing at the top panel, as was the top endband.
It was clear that the project was going to be a time-consuming one, but hopefully not as long as it took the insect to cause the damage!
To repair the book and make it safe to handle for the next generations of readers, and also to preserve an important volume from Newton’s private library collection, the book had to be taken apart into individual pieces. Each leaf was surface cleaned and repaired. Repairing insect-damaged areas in paper is quite tricky and gets even trickier when it comes to books. Insect damage has very regular sharp edge unlike a missing area caused by tearing. This rigid edge does not take repairs very easily. As the damage was concentrated in the same areas, adding any more thickness would have caused localised swelling to the text block, which could then cause further problems. The repair needed flexibility to allow the pages to turn easily and not cause any tension to the original paper. The paper of the leaves was also quite thin which added another complexity.
The paper repairs began by first applying a piece of very fine tissue called Whisper (only 4 grams of paper fibres per square metre!) to one side of each bifolio over the damaged area to hold everything in place. The tissue also acted as a layer onto which the infill of the missing area was then attached.
To cut out the infill – most of the time a very intricate design created by the larva – the leaf was placed over a light box with a protective layer of polyester sheet on top of it. A piece of heavier Japanese tissue was then placed over the missing area and the shape scored with a pointy tool. The infill was pasted in its place, pressed down, and left to dry.
Once all leaves were repaired the text block was re-sewn as originally on four cords.
New endbands were sewn using the same as original colour scheme. The boards were reattached and new leather was put on the spine followed by the original piece attached on top. Any remaining fragments were enclosed into polyester pockets within a pamphlet and are now kept with the book in a bespoke box.
The book is now in good and sound condition which allows it to be handled for many decades and centuries to come.