Editing 1870 (section)

=== July&ndash;September ===
* [[July 14]] &ndash; The [[Ems Dispatch]] is published, serving as ''[[casus belli]]'' for a war between [[Prussia]] and France.
* [[July 15]]
** [[Reconstruction Era]]: [[Georgia (U.S. state)|Georgia]] becomes the last former [[Confederate States of America|Confederate state of America]] to be readmitted to the Union.
** The British government admits the former [[Hudson's Bay Company]] territory of [[Rupert's Land]] and the [[North-Western Territory]] to the Dominion of Canada.
* [[July 18]] &ndash; ''[[Pastor aeternus]]'': [[Pope Pius IX]] declares [[papal infallibility]], in matters of faith and morals.
* [[July 19]] &ndash; [[Franco-Prussian War]]: France declares war on [[Prussia]].
* [[July 28]] &ndash; Start of [[Solar Saros 153]]. The final eclipse in this series will be in 3114.
* [[July 30]] &ndash; The '[[Griqualand West#Diggers Republic (1870-71)|Diggers' Republic]]' is proclaimed at Klipdrift in South Africa by diamond miners, with [[Stafford Parker]] as president.
* [[August 2]] &ndash; The [[Tower Subway]] beneath the [[River Thames]] in London, the world's first underground passenger "tube" railway, officially opens.<ref name="Pocket On This Day">{{cite book|title=Penguin Pocket On This Day|publisher=Penguin Reference Library|isbn=978-0-14-102715-9|year=2006}}</ref> Although this lasts as a railway operation only until November, it demonstrates the technologically successful first use of the cylindrical [[wrought iron]] [[tunnelling shield]], devised by [[Peter W. Barlow]] and [[James Henry Greathead]],<ref>{{cite book|last=Smith|first=Denis|title=Civil Engineering Heritage: London and the Thames Valley|publisher=Thomas Telford|year=2001|pages=22–23|isbn=978-0-7277-2876-0}}</ref> and of a permanent tunnel lining of [[cast iron]] segments.<ref>{{cite book|last=West|first=Graham|title=Innovation and the Rise of the Tunnelling Industry|publisher=Cambridge University Press|year=2005|pages=116–118|isbn=978-0-521-33512-6}}</ref>
* [[August 8]] &ndash; The [[Republic of Ploiești]], an uprising against [[Domnitor]] [[Carol I of Romania|Carol]] of [[Romania]], fails.
* [[August 24]] &ndash; The [[Red River Rebellion]] in Canada ends with the arrival of the [[Wolseley Expedition]] and the flight of [[Louis Riel]].
* [[September 2]] &ndash; [[Franco-Prussian War]]: [[Battle of Sedan]] &ndash; [[Prussia]]n forces defeat the French armies and take Emperor [[Napoleon III]] and 100,000 of his soldiers prisoner at [[Sedan, France]].
* [[September 4]] &ndash; Emperor [[Napoleon III]] of France is deposed and the [[French Third Republic|Third Republic]] is declared. [[Empress Eugénie]] flees to England with her son.
* [[September 6]] &ndash; [[Louisa Swain]] of Laramie, Wyoming, becomes the first woman in the United States to cast a vote legally since [[1807]].
* [[September 18]] &ndash; [[Old Faithful Geyser]] is observed and named by [[Henry D. Washburn]], during the [[Washburn–Langford–Doane Expedition]] to [[Yellowstone]] in Wyoming.
* [[September 19]] &ndash; [[Franco-Prussian War]]: The [[Siege of Paris (1870–1871)]] begins. From September 23, [[balloon mail]] is sent out of the city.
* [[September 20]] &ndash; [[Capture of Rome]]; With ''[[Bersaglieri]]'' soldiers entering Rome at [[Porta Pia]], the [[unification of Italy]] is completed, ending the last remnant of the [[Papal States]] and [[Temporal power (papal)|Papal temporal power]].