Editing 1808 (section)

=== April&ndash;June ===
* [[April]]
** A volcano erupts from an unknown location in the western Pacific. This causes a localized drop in marine air temperatures during this year and a worldwide drop in marine air temperature for the following decade.<ref>Chenoweth, M. (2001), Two major volcanic cooling episodes derived from global marine air temperature, AD 1807–1827, Geophys. Res. Lett., 28(15), 2963–2966, {{doi|10.1029/2000GL012648}}.</ref>
** Prussian philosopher [[Johann Gottlieb Fichte]] publishes his ''[[Addresses to the German Nation]]'', having delivered them over the winter at the [[Prussian Academy of Sciences]] in Berlin before crowded audiences.
* [[April 6]] &ndash; [[John Jacob Astor]] incorporates the [[American Fur Company]].
* [[April 16]] &ndash; Troops under Colonel [[Georg Carl von Döbeln|Carl von Döbeln]] clash with Russian troops in [[Pyhäjoki]], Finland.
* [[May 2]] &ndash; [[Peninsular War]]: [[Dos de Mayo Uprising]] &ndash; The people of [[Madrid]] rise up against the [[First French Empire|French]] troops.
* [[May 3]]
** [[Finnish War]]: The fortress of [[Suomenlinna|Sveaborg]] is lost by Sweden to Russia.
** The Madrid rebels who rose on May 2 are executed near the hill of [[Príncipe Pío (hill)|Príncipe Pío]] ([[Francisco Goya|Goya]] paints the fight and the execution in [[1814]]).
* [[May 6]] &ndash; [[Ferdinand VII of Spain|Ferdinand]] is forced to abdicate as King of Spain by Napoleon. This effectively ends the [[Anglo-Spanish War (1796–1808)]] as the United Kingdom allies with Spain and Portugal against the French in the [[Peninsular War]].
* [[June 12]] &ndash; [[Finnish War]]: A landing of Swedish troops at Ala-Lemu, near [[Turku]], fails.
* [[June 15]]–[[August 14]] &ndash; [[Peninsular War]]: [[First siege of Zaragoza]] &ndash; Spanish resist the French.
* [[June 19]] &ndash; [[Finnish War]]: A second landing of Swedish troops at Ala-Lemu fails.
* [[June 30]] 
** [[Finnish War]] &ndash; Battle of Turku: The Swedish [[archipelago fleet]] defeats the Russians.
** English chemist [[Humphry Davy]] informs the [[Royal Society]] of London of his isolation and discovery of two elements by electrolysis. From [[Lime (material)|lime]], he has produced [[calcium]] and established that lime is calcium oxide; by heating [[boric acid]] and [[potassium]] in a copper tube, he creates a substance he calls ''boracium'', which is eventually called [[boron]].<ref>Marco Fontani, Mariagrazia Costa and Mary Virginia Orna, ''The Lost Elements: The Periodic Table's Shadow Side'' (Oxford University Press, 2014)</ref> This year he also isolates [[magnesium]] and [[strontium]].