Rubber Eraser Day — April 15 [same day every year]
erase

Make no mistake about it, on April 15, 1770 Joseph Priestley recorded his discovery of a item made from rubber imported from Brazil that would erase — “rub out” — pencil marks.

Priestly wrote, “I have seen a substance excellently adapted to the purpose of wiping from paper the mark of black lead pencil.”

Priestly called his new product a “rubber.” In the U.S., they are called “erasers.”

As a clergyman, Joseph Priestley was considered an unorthodox philosopher, he supported the French Revolution and his unpopular views caused his home and chapel in Leeds, England, being burned in 1791. Priestley moved to Pennsylvania in 1794.
Joseph Priestley was a friend of Benjamin Franklin, who like Franklin was experimenting with electricity before turning his full attention to chemistry in the 1770s.

Priestley was a clergyman and chemist. He lived in Leeds. His philosophical views were considered to be unorthodox He supported the french Revolution. His house and chapel were burned down in 1791, supposedly by persons opposed to his views.

He moved Pennsylvania 1794.

He was a friend of Benjamin Franklin. Like Franklin, he experimented with electricity at first. Then, in the 1770s he changed to chemistry.

Links for information about Rubber Eraser Day:

http://inventors.about.com/od/pstartinventors/a/JosephPriestley.htm

http://www.babytalk.org/whats-new/Lets-talk-columns-2006/20060415-It’s-Rubber-Eraser-Day.html 

http://www.holidayinsights.com/other/rubbereraserday.htm

April 15 is also “Tax Day” in the U.S. — the due date for individual income tax returns. Many erasers are used to get the tax as low as possible.