Editing 1839 (section)

=== April–June ===
* [[April 9]] – The world's [[Cooke and Wheatstone telegraph|first commercial electric telegraph line]] comes into operation, alongside the [[Great Western Railway]] line in England, from [[London Paddington station]] to [[West Drayton]].
* [[April 19]] – The [[Treaty of London (1839)|Treaty of London]] establishes [[Belgium]] as a [[Monarchy|kingdom]], with its independence and neutrality guaranteed by the [[great power]]s of Europe. Half of the [[Province of Limburg (1815–39)|Limburg]] province of [[Belgium]] is added to the [[Netherlands]], giving rise to a [[Limburg (Belgium)|Belgian Limburg]] and [[Limburg (Netherlands)|Dutch Limburg]] (the latter being joined (from [[September 5]]) to the [[German Confederation]]).
* [[April 24]] – [[Boston University]] is established as the Newbury Biblical Institute in Vermont.
* [[May 7]]–[[May 11|11]] – The [[Bedchamber Crisis]] in the United Kingdom: Following the announcement by Prime Minister [[William Lamb, 2nd Viscount Melbourne|Lord Melbourne]] that he intends to resign,<ref> Mark Hovell, ''The Chartist Movement'' (Manchester University Press, 1966) p143.</ref> [[Robert Peel]] asks (for political reasons) that [[Queen Victoria]] dismiss some of her personal attendants, [[Lady of the Bedchamber|Ladies of the Bedchamber]], as a condition for his forming a government. Victoria refuses to accept the condition and Melbourne is persuaded to stay on as Prime Minister.<ref>{{cite hansard |title = Ministerial Explanations |house = House of Commons |date = 13 May 1839 |url = https://api.parliament.uk/historic-hansard/commons/1839/may/13/ministerial-explanations#column_984 |column_start = 984 |column_end = 985 |speaker = Robert Peel }}</ref>
* 13 May – First [[Rebecca Riots]] targeted against [[Turnpike trust|turnpikes]] in Wales, at [[Efailwen]] in [[Carmarthenshire]].<ref name="Welsh Academy">{{cite book |last=Davies |first=John |author2=Jenkins, Nigel  |title=The Welsh Academy Encyclopaedia of Wales |year=2008 |publisher=University of Wales Press |location=Cardiff|page=730 |isbn=978-0-7083-1953-6}}</ref>
* [[May 12]] – Socialist activist [[Louis Auguste Blanqui]] and the ''Société des Saisons'' begin an uprising against the government of [[France]]. The insurrection is suppressed, but not before 50 people are killed and 190 wounded. Blanqui is imprisoned until [[1848]].<ref> Jill Harsin, ''Barricades: The War of the Streets in Revolutionary Paris, 1830-1848'' (Palgrave Macmillan, 2002) p124.</ref>
* [[May 22]] – Former British statesman [[John Lambton, 1st Earl of Durham|Lord Durham]], as President of the [[New Zealand Company]], formally asks the British government for permission to colonize [[New Zealand]], and to establish a colonial government under the sovereignty of the United Kingdom.<ref>T. Lindsay Buick, ''The French at Akaroa: An Adventure in Colonization'' (Cambridge University Press, 1928)(reprinted 2011) p294</ref>
* [[May 23]] – Turkish troops cross the [[Euphrates]] River and invade Syria, but are defeated in battle in June.<ref>Charles Alan Fyffe, ''A History of Modern Europe'', Volume 2 (Cassell & Company, 1886) p453</ref>
* [[June 3]] – [[Destruction of opium at Humen]] begins, ''[[casus belli]]'' for Britain to open the 3-year [[First Opium War]] against [[Qing dynasty]] China. A rapid rise in the sale of opium in China to over 40,000 chests (~{{convert|56,000|kg}} per annum)<ref>{{cite book|last=Greenberg|first=Michael|author-link=Michael Greenberg (economist)|title=British Trade and the Opening of China 1800-1841|year=1969|format=preview|url=https://books.google.com/books?id=QNo8AAAAIAAJ|page=113|quote=expansion in imports from 16,550 chests in the season 1831-2 to over 30,000 in 1835-6, and 40,000 in 1838-9}}</ref><ref name=CIH>{{cite book|title=The Cambridge Illustrated History of China|editor1-last=Ebrey|editor1-first=Patricia Buckley|editor1-link=Patricia Buckley Ebrey|year=2010|publisher=Cambridge University Press|isbn=978-0-521-19620-8|page=236|edition=2nd|chapter=Chapter 9: Manchus and Imperialism: The Qing Dynasty 1644–1900}}</ref> has caused the Chinese government to dispatch scholar-official [[Lin Zexu]] to [[Guangzhou]] to deal with the [[History of opium in China|growing problem of opium addiction]].
* [[June 22]] – [[Louis Daguerre]] receives a patent for his camera (commercially available by September at the price of 400 francs).
* [[June 27]] – The [[emperor]] of the [[Sikh Empire]], [[Maharaja Ranjit Singh]], dies at 58.