How do you tell when you're out of invisible ink?
Steven Wright (December 6 1955-)
Pencil with eraserIn 1858, the first U.S. patent for a combination lead pencil and eraser was issued to Hyman L. Lipman, of Philadelphia, Pa. (No. 19,783). The pencil was made in the usual manner, with one-fourth of its length reserved inside one end to carry a piece of prepared india-rubber, glued in at one edge. Thus cutting one end prepared the lead for writing, while cutting the other end would expose a small piece of india rubber. This eraser was then conveniently available whenever needed, and not subject to being mislaid. Further, the eraser could be sharpened to a finer point to make a more precise erasure of fine lines in a drawing, or cut further down if the end became soiled. |
