A writing slate is a thin piece of flat material used as a medium for writing. The slate material itself, a stony substance, is “a metamorphic rock created by the recrystallization of the minerals in shale from clay to parallel-aligned, flat, flake-like minerals such as mica”. The writing slate consisted of a piece of slate, either 4x6 inches or 7x10 inches, which was encased in a wooden frame. A precise date range for writing slates of this type remains unclear. Usually, a piece of cloth or slate sponge was used to clean it and this was sometimes attached with a string to the bottom of the writing slate. Typically, the writing slate was used by children during the days of the one-room schoolhouse to practice writing and arithmetic during classes or at home. Writing slates, however, were also used in multi-room schools until the twentieth century. The writing slate was also sometimes used by industry workers to keep track of goods and by sailors to calculate their geographical location while at sea. Sometimes multiple pieces of slate were bound together into a “book” and horizontal lines were etched onto the slate surface as a guide for neat handwriting.
The exact origins of the writing slate remain unclear, but references to its use can be found as far back as the fourteenth century and evidence suggests that it was used on occasion through the sixteenth and seventeenth centuries as well. The central time period for the writing slate, however, “appears to begin in the later eighteenth century, when developments in sea and land transport permitted the gradual expansion of slate quarrying in Wales and the growth of a substantial slate workshop industry.” By the nineteenth century, writing slates were used around the world in nearly every school and were a central part of the overall slate industry. At the dawn of the twentieth century, writing slates were still the primary tool in the classroom for students and it was not until the 1930s (or later) that writing slates started being replaced by more modern methods. However, writing slates did not become obsolete. They are still made today, though in small quantities.
Uses of slate and its quality
Slate itself had already been in use as a building material long before it was used for writing slates. Indeed, the use of slate as a roofing material can be traced back to at least the Roman era in Wales, about the first century AD to the fourth century AD. The slate used in roofing had to be of very high quality, as the material is prone to cracking and can be broken if not handled with great care. Slate used for writing slates also had to be of good quality because of the thinness required. Mining slate of this quality is a straightforward process since slate splits into nearly perfectly flat surfaces. The difficult part of the mining process is sorting out the quality slate from slate with “cats” or flaws. Once the slate is sorted properly it can be made into any size required. Roofing slate is actually still in use today, primarily for the restoration of eighteenth and nineteenth century buildings, as it is fairly expensive.
- Robert N. Pierport, “Slate Roofing”, APT Bulletin, Vol. 19(2) (1987), 10.
- “Standard Sizes of Blackboard Slate”, U.S Department of Commerce: National Bureau of Standards (1966), 3.
- Peter Davies, “Writing Slates and Schooling”, Australasian Historical Archaeology, Vol. 23 (2005), 63-64.
- Davies, 63.
- Davies, 64-65 .
- Pierport, 11-13.