Editing 1827 (section)

=== April–June ===
* [[April 7]] – [[John Walker (inventor)|John Walker]] begins selling his invention, the "Lucifer" friction [[match]], in England.<ref name="Pocket On This Day">{{cite book|title=Penguin Pocket On This Day|publisher=Penguin Reference Library|isbn=0-14-102715-0|year=2006}}</ref>
* [[April 8]] – [[Battle of Monte Santiago]]: A squadron of the Brazilian Imperial Navy defeats [[Argentina|Argentine]] vessels after a two-day naval battle.
* [[April 10]] – [[George Canning]] succeeds [[Robert Jenkinson, 2nd Earl of Liverpool|Lord Liverpool]] as [[Prime Minister of the United Kingdom]].
* [[April 23]] – Scottish-born novelist [[John Galt (novelist)|John Galt]] founds the town of [[Guelph]] in [[Upper Canada]].
* [[April 24]] – [[Greek War of Independence]]: [[Battle of Phaleron]] – Ottoman troops defeat the Greek rebels.
* [[April 26]] – The [[Royal Netherlands Navy]]'s British-built [[paddle steamer]] ''[[Steamboat#Ocean-going steamships|Curaçao]]'' sets off on the first [[transatlantic crossing]] by steam, departing from [[Hellevoetsluis]] in the Netherlands to [[Paramaribo]] in the Netherlands South American colony of Dutch Guiana. The ship arrives after a voyage of four weeks.<ref name=Curacao>{{cite web |title=Steamship Curaçao |url=http://www.vrcurassow.com/2dvrc/sscuracao/sscuracao.html |access-date=2011-02-02 |archive-url=https://web.archive.org/web/20101224202256/http://vrcurassow.com/2dvrc/sscuracao/sscuracao.html |archive-date=December 24, 2010 |url-status=live}}</ref>
* [[April 29]] – The Fly Whisk Incident in [[Ottoman Algeria]]: [[Hussein Dey]] slaps French consul [[Pierre Deval (diplomat)|Pierre Deval]] on the face, eventually leading to the [[Invasion of Algiers in 1830]].
* [[May 1]] – [[Georg Ohm]] publishes ''Die galvanische Kette, mathematisch bearbeitet'' (tr., ''The Galvanic Circuit Investigated Mathematically'') in which [[Ohm's law]] appears for the first time.
* [[May 20]] – [[Zarafa (giraffe)|Zarafa]], the first [[giraffe]] to be seen in Europe for over three centuries, arrives in [[Marseille]] as a gift from the [[Ottoman Empire|Ottoman]] Viceroy of [[Egypt]], [[Mehmet Ali Pasha]], to [[Charles X of France|King Charles X]] of [[France]]. The giraffe then begins a 50-day journey to [[Paris]], walking with its handlers toward [[Paris]] where it will arrive on July 9.<ref name=Zarafa>{{cite book |last=Allin |first=Michael |title=Zarafa: A Giraffe's True Story, from Deep in Africa to the Heart of Paris |year=1999 |publisher=Delta Books |isbn=0-385-33411-7}}</ref>
* [[May 21]] – The [[Maryland Democratic Party]] is founded by supporters of [[Andrew Jackson]] in [[Baltimore]], and hosts its first meeting at the Baltimore Atheneum.
* [[May 24]] – The [[Royal Netherlands Navy]]'s British-built [[paddle steamer]] ''[[Steamboat#Ocean-going steamships|Curaçao]]'' completes the first [[transatlantic crossing]] by steam, arriving in [[Paramaribo]] in [[Suriname|Dutch Guiana]] (now Suriname) four weeks after its April 26 departure from the Netherlands.<ref name=Curacao/>
* [[May 25]] – Romanian inventor [[Petrache Poenaru]] receives a French [[patent]] for the invention of the first [[fountain pen]].
* [[June 4]] – French inventor [[Joseph Niépce]] sends a package to [[Louis Daguerre]] revealing the existence of his invention, "heliography", where an image can be reproduced onto a pewter plate and then reprinted.<ref>"A Photo-engraving of 1826", in ''The Process Photogram and Illustrator'' (January 1905), p82</ref> In 1829, the two will begin a partnership, and Daguerre will perfect Niépce's photographic process to reproduce images more quickly.
* [[June 7]] – Greek defenders in [[Athens]] surrender to Egyptian forces under the command of General [[Reşid Mehmed Pasha|Rashid Pasha]].<ref>John Frost, ''History of Ancient and Modern Greece'' (Lincoln and Edmands, 1831) p355</ref><ref>Afaf Lutfi al-Sayyid Marsot, ''Egypt in the Reign of Muhammad Ali'' (Cambridge University Press, 1984) p208</ref>