Births on May 6

Willem de Sitter, Dutch mathematician, physicist, and astronomer (d. 1934)

Willem de Sitter (6 May 1872 – 20 November 1934) was a Dutch mathematician, physicist, and astronomer.

5 Mar

Railway air brake
George Westinghouse patents the air brake.
22 Mar

Gender equality
Illinois becomes the first state to require gender equality in employment.
22 May

Amnesty Act
Reconstruction Era: President Ulysses S. Grant signs the Amnesty Act into law, restoring full civil and political rights to all but about 500 Confederate sympathizers.
18 Nov

United States presidential election, 1872
Susan B. Anthony and 14 other women are arrested for illegal voting in the United States presidential election of 1872.
9 Dec

P. B. S. Pinchback
In Louisiana, P. B. S. Pinchback becomes the first African-American governor of a U.S. state.