Edison Electric pen, c.1885.

Thomas Edison’s electric pen is a much less known, and much less successful, example of his work. It was one of the first inventions at Menlo Park, developed in 1875 and patented in August 1876 with the help of his British assistant Charles Batchelor.

The battery powered pen could make 50 punctures a second onto paper, creating a stencil of what you want to write (or draw) in multiple layers of paper. The layers would then be inked over in an accompanying flatbed ‘duplicating press’, where a roller would press ink through the holes in the paper. This allowed many copies to be made at once, like an early photocopier. Edison claimed over 5000 copies could be made at once.