Tracing Paper: Flax Tow Beaten to a Clear Pulp, Ure 1839

Tracing paper is paper you can see through. Andrew Ure (1839) says the best, sometimes called vegetable paper, is made from the refuse of the flax mills, the tow, beaten without fermenting into a semi-transparent paste that dries into a transparent sheet. The picture: the vat room of an 18th-century paper mill, the vatman forming a sheet and the press behind (Diderot's Encyclopédie).