Joseph Priestley & Edward Nairne Invent the Rubber Eraser?

On April 15, 1770 Joseph Priestley described a vegetable gum which has the ability to rub out pencil marks: "I have seen a substance excellently adapted to the purpose of wiping from paper the mark of black lead pencil." He called the substance "rubber."

Also in 1770 Edward Nairne, an English engineer, is credited with developing the first widely-marketed rubber eraser for an inventions competition. He reportedly sold natural rubber erasers for the high price of 3 shillings per half-inch cube.  This was the first practical application of rubber in Europe.