1931

January 1931 January 2 – South Dakota native Ernest Lawrence invents the cyclotron, used to accelerate particles to study nuclear physics. January 4 – German pilot Elly Beinhorn begins her flight to Africa. January 22 – Sir Isaac Isaacs is sworn in as the first Australian-born Governor-General of Australia. January 25 – Mohandas Gandhi is again released from imprisonment in India. January 27 – Pierre Laval forms a government in France. February 1931 February 4 – Soviet leader Joseph Stalin gives a speech calling for rapid industrialization, arguing that only strong industrialized countries will win wars, while "weak" nations are "beaten". Stalin states: "We are fifty or a hundred years behind the advanced countries. We must make good this distance in ten years. Either we do it, or they will crush us." The first five-year plan in the Soviet Union is intensified, for the industrialization and collectivization of agriculture. February 10 – Official inauguration ceremonies for New Delhi as the capital of India begin. February 16 – Pehr Evind Svinhufvud is elected president of Finland. February 21 – Peruvian revolutionaries hijack a Ford Trimotor aeroplane, and demand that the pilot drop propaganda leaflets over Lima. March 1931 March 5 – The British viceroy of India and Mohandas Gandhi sign the Gandhi–Irwin Pact. March 7 – The Finnish Parliament House opens in Helsinki, Finland. March 11 – The Ready for Labour and Defence of the USSR programme, abbreviated as GTO, is introduced in the Soviet Union. March 23 – Indian revolutionary leaders Bhagat Singh, Shivaram Rajguru and Sukhdev Thapar are hanged for conspiracy to murder in the British Raj. March 31 – An earthquake destroys Managua, Nicaragua, killing 2,000 people. April 1931 April 1 – The Second Encirclement Campaign against Jiangxi Soviet in China is launched by the Kuomintang government, to destroy the Communist forces in Jiangxi Province. April 6 – The Portuguese government declares martial law in Madeira and in the Azores, because of the Madeira uprising in Funchal.