Purchase is announced to the American people. July 5 – The convention of Artlenburg leads to the French occupation of Hanover (which had been ruled by the British king). July 23 – Robert Emmet's uprising in Ireland begins. July 26 – The wagonway between Wandsworth and Croydon is opened, being the first public railway line in England. August 3 – The British begin the Second Anglo-Maratha War, against the Scindia of Gwalior. August 31 – The Lewis and Clark Expedition begins as Lewis and a crew of 11 depart on the Ohio River. September 6 – John Dalton, British scientist, begins using symbols to represent the atoms of different elements. September 11 – Second Anglo-Maratha War – Battle of Delhi: British troops under General Lake defeat the Marathas of Scindia's army, under General Louis Bourquin. September 20 – Irish rebel Robert Emmet is executed. September 23 – Battle of Assaye, India: British-led troops defeat Maratha forces. October–December October 14 – Orissa, an area of India along the Bay of Bengal that now comprises the Indian state of Odisha, is occupied by the British under the British East India Company, after the Second Anglo-Maratha War. The Maratha Empire formally cedes the area in the Treaty of Deogaon, signed on December 17. October 20 – The Senate ratifies the Louisiana Purchase Treaty, doubling the size of the United States. November 18 – Battle of Vertières: The Haitian army, led by Jean-Jacques Dessalines, defeats the army of Napoleon. November 30 – The Balmis Expedition starts in Spain, with the aim of vaccinating millions against smallpox in Spanish America and the Philippines. At the Cabildo in New Orleans, Spanish representatives Governor Manuel de Salcedo and the Marqués de Casa Calvo officially transfer Louisiana (New Spain) to French representative Prefect Pierre Clément de Laussat. Barely three weeks later, France transfers the same land to the United States. December 9 – The proposed Twelfth Amendment to the United States Constitution, requiring that electoral ballots distinctly list the choice for president and the choice for vice president, is approved by Congress for submission to the states for ratification; passed in the wake of the problems in the 1800 presidential election, the amendment is ratified by 13 of the 17 states and is proclaimed in effect on September 25, 1804. December 20 – The Louisiana Purchase is completed as the French prefect, de Laussat, formally transfers ownership of