Editing 1846 (section)

=== July–September ===
* [[July 7]] – [[Mexican–American War]]: [[Battle of Monterey]] – Acting on instructions from Washington, D.C., [[Commodore (USN)|Commodore]] [[John Drake Sloat]] orders his troops to occupy [[Monterey, California|Monterey]] and [[Yerba Buena, California|Yerba Buena]], thus beginning the United States annexation of [[California]].
* [[August 22]] – The [[Second Federal Republic of Mexico]] is established.
* [[August 28]] – The [[New Zealand Constitution Act 1846]] is passed by the [[Parliament of the United Kingdom]] with the intention of granting self-government to the British [[Colony of New Zealand|colony]]. Governor [[George Grey]] suspends implementation of the majority of the Act, with the exception of the creation of [[New Ulster Province|New Ulster]] and [[New Munster Province]]s, and it is superseded by the [[New Zealand Constitution Act 1852]].<ref>{{cite book|first=Paul |last=Moon|title=New Zealand Birth Certificates – 50 of New Zealand's Founding Documents|author-link=Paul Moon|year=2010|publisher=AUT Media |isbn=9780958299718}}</ref>
* August – Canadian physician and geologist [[Abraham Pineo Gesner]] demonstrates a process to refine a liquid fuel, which he calls [[kerosene]], from [[coal]], [[bitumen]] or [[oil shale]].
* [[September 3]] – [[Electric Telegraph Company]] founded in Britain.
* [[September 7]] – The portion of the [[District of Columbia]] in the United States that was ceded by [[Virginia]] in [[1790]] is [[District of Columbia retrocession#Virginia retrocession|re-ceded to Virginia]].
* [[September 10]] – [[Elias Howe]] is awarded the first United States patent for a [[sewing machine]], using a [[lockstitch]] design.<ref>{{US patent|4750}}</ref>
* [[September 12]] – Poets [[Elizabeth Barrett]] and [[Robert Browning]] marry privately in London, departing a week later for the continent.
* [[September 14]] – [[Jang Bahadur]] and his brothers massacre about 40 members of the Nepalese palace court.
* [[September 19]] – [[Our Lady of La Salette]], a [[Marian apparition]], is said to have been seen by two children at [[La Salette-Fallavaux]] in France.
* [[September 23]] – [[Discovery of Neptune]]: The planet is observed for the first time by German astronomers [[Johann Gottfried Galle]] and [[Heinrich Louis d'Arrest]], as predicted by British astronomer [[John Couch Adams]] and French astronomer [[Urbain Le Verrier]].
* [[September]] – The [[Second Carlist War]] (or the War of the Matiners or Madrugadores) begins in Spain.