
A clean slate: a slate and slate pencil. A set of slates and originally 1 batch of slate pencils wrapped in shiny paper. L. & C. Hardtmuth. After Joseph Hardtmuth had succeeded in producing pencil leads out of clay and graphite powder, he founded his pencil factory in Vienna in 1790.
Deutsches Buch- und Schriftmuseum der Deutschen Nationalbibliothek Leipzig, Photograph: Michael Setzpfandt