Patent Model of a Metallograph, or Embossing Pen for Autographic Printing

Setchell, George C. · ca 1879

This patent model demonstrates an invention for a metallograph, and was granted patent number 215792. With this tool, a writer could turn a sheet of metal into a printing plate as he wrote on it. The air-powered writing instrument made a series of sharp blows to the metal, knocking out projections on the back of the sheet. The projections formed a facsimile of the writing in reverse and in relief for printing at a type press.