Editing 1840 (section)

=== April–June ===
* [[April]] – The [[Raleigh and Gaston Railroad]] is completed from [[Raleigh, North Carolina|Raleigh]] to near [[Weldon, North Carolina]].<ref>{{cite web|url=http://www.historync.org/railroads.htm|title=Railroads — prior to the Civil War|work=North Carolina Business History|year=2006|access-date=2011-12-02|archive-url=https://web.archive.org/web/20110726152211/http://historync.org/railroads.htm|archive-date=July 26, 2011|url-status=dead}}</ref>
* [[April 2]] – The [[Washingtonian movement]] for [[teetotalism]] is founded by a group of [[alcoholic]]s in [[Baltimore]], Maryland.
* [[April 3]] – [[Johnny Appleseed]] meets [[Abraham Lincoln]], and plants apple trees in [[New York City]].
* [[April 15]] – [[King's College Hospital]] opens in London.
* [[May 1]] – Britain issues the [[Penny Black]], the world's first [[postage stamp]]; it becomes valid for the pre-payment of postage from [[May 6]].
* [[May 7]] – [[Great Natchez Tornado]]: A massive tornado strikes [[Natchez, Mississippi]] during the early afternoon. Before it is over, 317 people are killed and 109 injured (the second deadliest tornado in U.S. history).
* [[May 21]] – [[New Zealand]] is declared a British colony.
* [[June 7]] – On the death of [[Frederick William III of Prussia]], he is succeeded on the throne of the [[Kingdom of Prussia]] (which he has ruled for more than 40 years) by his eldest son [[Frederick William IV of Prussia|Frederick William IV]].
* [[June 12]]–[[June 23|23]] – The [[World Anti-Slavery Convention]] is organised by the [[British and Foreign Anti-Slavery Society]], at [[Exeter Hall]] in London, England. Arguments over the exclusion of women from the convention have important ramifications for the movement for [[women's suffrage in the United States]].
* [[June 18]] – [[Maria massacre|''Maria'' massacre]]: British [[brigantine]] ''Maria'' is wrecked off [[South Australia]]. All 26 passengers and crew make it to the shore but none survive the trek to safety over the following two weeks, most being massacred by [[Aboriginal Australians]].<ref>{{cite web|url=http://firstsourcesguide.com/uploads/3/2/4/6/3246279/case_study_-_wreck_of_the_maria.pdf|url-status=dead|archive-url=https://web.archive.org/web/20181001182534/http://firstsourcesguide.com/uploads/3/2/4/6/3246279/case_study_-_wreck_of_the_maria.pdf|archive-date=2018-10-01|accessdate=2024-08-14|title=Wreck of the ''Maria'' Incident|publisher=First Sources}}</ref>