History of eraser and liquid paper

eraser:
          The first eraser is been invented in 1770 when Joseph Priestley discovered a vegetable gum that possessed the ability to 'rub out' pencil marks. When that time, eraser easy to decomposed. So most of erasers thart we are using today are are made from synthetic rubber, which also has to be cured, and it is now made from chemicals, not tree sap.

liquid paper:
          Bette Nesmith Graham is the creater of liquid paper. She sought a better way to correct typing errors when she during her job. She remembered that artists painted over their mistakes on canvas, so why couldn’t typists paint over their mistakes? So Bette Nesmith Graham invented liquid paper, her invention became more popular in her office,every one using it. By 1967, it had grown into a million dollar business. In 1968, she moved into her own plant and corporate headquarters, automated operations, and had 19 employees. That year Bette Nesmith Graham sold one million bottles. Graham died in 1980, six months after selling her corporation for $47.5 million.