March 13, 1781 Astronomer William Herschel discovers the planet Uranus.
March 14, 1794 Eli Whitney patents the cotton gin, which separates cotton fiber from seed.
March 15, 44 B.C. Julius Caesar is assassinated as he enters the Roman Senate.
March 16, 1802 President Thomas Jefferson signs a law establishing the United States Military Academy at West Point.
March 18, 1931 Schick begins to market the electric razor.