Specious arithmetick
Specious arithmetick is a 1750 manuscript-style geometry and arithmetic text, handwritten in ink with ruled diagrams, attributed to Dibner and held by the Smithsonian Libraries, likely made as instruction for students. The pictures are small pen diagrams of circles, angles, bisected lines, parallelograms and triangles beside dense handwritten proofs, so a designer could take inspiration from their clean geometric linework and tidy hand-lettered layout.
