Preparation for the new Toy Halls of Fame is in full swing at The Strong. Part of the preparation for the exhibit’s opening in September 2015 involves assessing objects to make sure that they can be safely displayed in a way that will preserve the artifacts while allowing guests to enjoy them during their visits. Recently, I examined one of the museum’s greatest treasures, “Europe Divided into its Kingdoms.” This 1766 puzzle, which depicts a map of Europe drawn by London cartographer John Spilsbury, is widely accepted as the world’s very first jigsaw puzzle. Spilsbury created his “dissected map” as an educational tool for children by pasting the map onto a thin mahogany board and then cutting the pieces along the geographical lines. Examples of Spilsbury’s dissected maps are rare, and only a few are known to exist in public collections. When I first examined the puzzle, I marveled at its excellent condition. I was particularly impressed that the wood has not warped significantly over the puzzle’s two and a half century lifetime. Wood is hygroscopic, which means that it reacts to changes in its environment, especially humidity, by expanding and contracting. Wood usually expands across the grain, which is the direction that the fibers orient themselves as the tree grows. The grain is usually easily visualized on a piece of wood by looking at the dark and light patterns created by the growth rings. Because trees grow in a circle, the regularity of the grain in a board depends on how the board is cut from the tree. If the board is a tangential cut, the distribution of the grain is uneven which can cause warping. If the board is a radial cut the grain is distributed more evenly. The wood still reacts to changes in the environment, but it moves evenly across the whole board.
One way to visualize this is to think about another National Toy Hall of Fame inductee, Slinky. When a Slinky starts out in your hand, all of the springs are stacked into a neat, straight column. When you begin to apply and release pressure, however, the Slinky wiggles and waves into a variety of different curves and shapes. This mimics the way a tangentially cut board responds to changes in the environment. A Slinky pull toy, however, starts out in a straight line and, although you pull on the string, the spring stays straight as you apply and release pressure. This mimics a radial cut. Spilsbury’s puzzle was created using a piece of radial cut mahogany, which has allowed it to expand and contract evenly across the entire puzzle, and is why the puzzle has survived for so long without warping.
The most fascinating thing about this puzzle, however, is that the wood is not the only part that has this hygroscopic characteristic. Paper also has a grain, which is caused by the way that paper fibers align during manufacturing. The Spilsbury puzzle has paper attached to both sides. Because the paper was handmade, it has a distinct pattern of small “laid” lines that make it very easy to determine the grain direction. The grain on “laid” paper is perpendicular to the close-set lines that are easily visible on the back of the puzzle pieces. Not only did Spilsbury pay attention to the grain of the wood for his puzzle, but he made sure that the grain of the attached paper was oriented in the same direction so that the two materials would move in tandem when responding to changes in their environment. This eliminated the possibility that the paper and the wood would be pulling on each other in opposing directions, which might have caused warping, tearing of the paper, or a number of other calamities that would have been disastrous for this most important of jigsaw puzzles.
Spilsbury obviously paid close attention to his materials and how they were used, and this has contributed greatly to the object’s current condition. Spilsbury’s thoughtful craftsmanship has contributed to the preservation of the world’s first jigsaw puzzle, and has allowed many generations to enjoy and research this important artifact. You, too, can enjoy the Spilsbury puzzle when the new Toy Halls of Fame opens at The Strong this fall.