Editing 1873 (section)

===January&ndash;March===
* [[January 1]]
** [[Japanese calendar|Japan adopts the Gregorian calendar]].
** The [[California Penal Code]] goes into effect.
* [[January 17]] &ndash; [[American Indian Wars]]: [[Modoc War]]: [[First Battle of the Stronghold]] &ndash; Modoc Indians defeat the [[United States Army]].
* [[February 11]] &ndash; The Spanish [[Cortes Generales|Cortes]] deposes King [[Amadeo I of Spain|Amadeus I]], and proclaims the [[First Spanish Republic]].
* [[February 12]] 
** [[Emilio Castelar]], the former foreign minister, becomes prime minister of the new Spanish Republic.
** The [[Coinage Act of 1873]] in the United States is signed into law by President [[Ulysses S. Grant]]; coming into effect on [[April 1]], it ends [[bimetallism]] in the U.S., and places the country on the [[gold standard]].
* [[February 20]]
** The [[University of California]] opens its first [[medical school]] in [[San Francisco]].
** British naval officer John Moresby discovers the site of [[Port Moresby]] in Papua New Guinea, and claims the land for Britain.
* [[March 3]] &ndash; [[Censorship]]: The [[United States Congress]] enacts the [[Comstock Law]], making it illegal to send any "obscene, lewd, or lascivious" books through the mail.
* [[March 15]] &ndash; The [[Phi Sigma Kappa]] student fraternity is founded at the [[Massachusetts Agricultural College]].
* [[March 22]] &ndash; Emancipation Day for [[Puerto Rico]]: Most slaves are freed.
* [[March 29]] &ndash; The ''[[Rio Tinto Company]]'' is formed in Spain, following the [[February 17]] purchase of the Rio Tinto Mine from the Spanish government by a British investment group.