Editing 1939 (section)

=== August ===
{{main|August 1939}}
* [[August 2]] &ndash; The [[Einstein–Szilard letter]] is signed by [[Albert Einstein]], advising [[President of the United States]] [[Franklin D. Roosevelt]] of the potential use of [[uranium]] to construct an [[atomic bomb]]. It is delivered on October 11 and leads to the first meeting on October 21 of the Advisory Committee on Uranium.<ref>{{cite book|last1=Lanouette|first1=William|last2=Silard|first2=Bela|title=Genius in the Shadows: A Biography of Leo Szilárd: The Man Behind The Bomb|location=New York|publisher=Charles Scribner's Sons|year=1992|isbn=978-0-684-19011-2|url-access=registration|url=https://archive.org/details/geniusinshadowsa00lano}}</ref>
* [[August 4]] &ndash; Prime Minister [[Neville Chamberlain]] dismisses the Parliament of the United Kingdom until October 3.
* [[August 19]] &ndash; [[Adolf Hitler]], after evaluating the pace of [[Molotov–Ribbentrop Pact|non-aggression negotiations with the Soviet Union]], orders the ''[[Kriegsmarine]]'' to begin the opening operations for ''[[Fall Weiss (1939)|Fall Weiß]]'', the invasion of Poland. The {{Ship|German pocket battleship|Admiral Graf Spee}}, along with the {{Ship|German pocket battleship|Deutschland}}, as well as dozens of U-boats, cast off for their advance positions. Hitler spends the next few days worrying that the Russians will not come to terms in time for the rest of the invasion plans to unfold as scheduled.<ref name=Shirer>{{cite book|last=Shirer|first=William L.|author-link=William L. Shirer|date=2011|title=[[The Rise and Fall of the Third Reich]]|location=New York|publisher=Simon & Schuster|isbn=9781451651683}}</ref>
* [[August 20]] &ndash; Armored forces under the command of Soviet General [[Georgy Zhukov]] deliver a decisive defeat to [[Imperial Japanese Army]] forces in the Japanese-Soviet border war in [[Inner Mongolia]].
* [[August 23]] &ndash; The [[Molotov–Ribbentrop Pact]] is signed between Germany and the Soviet Union, a neutrality treaty that also agrees to division of spheres of influence (Finland, [[Estonia]], [[Latvia]], eastern Poland and Bessarabia (modern-day [[Moldova]]), north-east province of [[Romania]] to the [[Soviet Union]]; [[Lithuania]] and western Poland to Germany). Its annex reassigns Lithuania to the Soviet Union.
* [[August 24]] &ndash; As details of the Molotov–Ribbentrop Pact become public, British Prime Minister [[Neville Chamberlain]] recalls the [[Parliament of the United Kingdom]] several weeks early. In a burst of legislation, the [[Emergency Powers (Defence) Act 1939]] gives full authority to defence regulations, the British [[Royal Navy]] is to be put on a war footing, all military leave is to be cancelled, [[military reserve force]]s are to be called up, especially coast defence, radar and anti-aircraft units, and [[Civil Defence]] workers are placed on alert. In addition, the last British and French private citizens in Germany are advised to return home by their respective Governments.
* [[August 25]] 
** The German Foreign Ministry cuts off all telegraph and telephone communication with the outside world, in accordance with the plan for ''[[Fall Weiss (1939)|Fall Weiß]]''. At approximately 1830 Central European time, Adolf Hitler postpones ''Fall Weiß'' for 5 days, after receiving a message from [[Benito Mussolini]] that he will not honor the Pact of Steel if Germany attacks Poland, and because Chamberlain's government has not fallen as a result of the German-Soviet Non-Aggression Pact. Some units already in their forward positions (the attack is scheduled for 0430 the next day) do not get the word in time and attack various targets along the border. This same day, [[Neville Chamberlain]] gives [[Edward Rydz-Śmigły]] his "ironclad guarantee" of assistance if Poland is attacked by Germany.
** [[1939 Coventry bombing]]: An [[Irish Republican Army (1922–69)|Irish Republican Army]] bomb explodes in the centre of [[Coventry]], England, killing 5 people.
* [[August 26]]
** The first televised [[Major League Baseball]] games are shown on experimental station [[W2XBS]] in the United States: a double-header between the [[Cincinnati Reds]] and the [[Brooklyn Dodgers]] at [[Ebbets Field]].
** The ''[[Kriegsmarine]]'' orders all German-flagged merchant ships to head to German ports immediately, in anticipation of the invasion of Poland.
* [[August 27]] &ndash; A [[Heinkel He 178]], the first turbojet-powered aircraft, flies for the first time, with Captain Erich Warsitz in command.
* [[August 28]] &ndash; French ocean liner {{SS|Normandie}} heads into [[New York Harbor]], where she will be interned on September 3, and cut up for scrap, beginning in 1946.
* [[August 30]] &ndash; Poland begins a [[mobilization]] against [[Nazi Germany]].
* [[August 31]] &ndash; [[Operation Himmler]]: Nazi German troops posing as Poles stage a series of [[false flag]] operations on the border (including the [[Gleiwitz incident]]), giving a pretext for the invasion of Poland.