April 4:

• 1832 - The HMS Beagle, carrying Charles Darwin on its second voyage, arrived at Rio de Janeiro, Brazil. Darwin would soon depart on a scientific expedition inland.
• 1864 - Joseph Pitty Couthouy died after succumbing to a rifle wound incurred the previous day while commanding the USS Chillicothe off the coast of Grand Ecore, Louisiana during the Red River Campaign of the American Civil War.
• 1897 - Tiberius Cornelis Winkler died in Haarlem, Netherlands at age 74.
• 1899 - Vasiliy E. Ruzhentsev was born in Moscow, Russia.
• 1952 - Henry Woods died in Meldreth, England.
• 1969 - Friedrich von Huene died in Tübingen, Germany at age 94.