were imported from Africa to the United States. Still, the abolitionist movement began to gain ground in this period. Britain enacted the Slave Trade Act 1807, which barred the trade of slaves in Great Britain (though slavery was still legal). The United States enacted a similar ban in 1808. However, Napoleon revoked the French Empire's ban on slavery with the Law of 20 May 1802. On 30 August 1800, under the cloak of religious meetings, Gabriel Prosser and Jack Bowler planned a slave rebellion in Richmond, Virginia. The rebellion was postponed due to poor weather and was ultimately unsuccessful because of unnamed two slaves betraying the cause. Prominent political events 1800 The unfinished White House (at the time known as the "Executive Mansion") housed its first president, President John Adams, on 1 November 1800. 1801 Under the District of Columbia Organic Act of 1801, Washington, D.C., a new planned city and capital of the United States, was placed under the jurisdiction of the U.S. Congress. The Kingdom of Great Britain and the Kingdom of Ireland merge into the United Kingdom of Great Britain and Ireland in 1801. 1803 United States doubles its size with territories gained from Napoleon Bonaparte in the Louisiana Purchase. World leaders 1800 – 1801 – 1802 – 1803 – 1804 – 1805 – 1806 – 1807 – 1808 – 1809 Colonies Science and technology Electricity This decade contained some of the earliest experiments in electrochemistry. In 1800 Alessandro Volta constructed a voltaic pile, the first device to produce a large electric current, later known as the electric battery. Napoleon, informed of his works, summoned him in 1801 for a command performance of his experiments. He received many medals and decorations, including the Légion d'honneur. Also in 1800, William Nicholson and Johann Wilhelm Ritter succeeded in decomposing water into hydrogen and oxygen by electrolysis. Soon thereafter Ritter discovered the process of electroplating. He also observed that the amount of metal deposited and the amount of oxygen produced during an electrolytic process depended on the distance between the electrodes. By 1801 Ritter observed thermoelectric currents and anticipated the discovery of thermoelectricity by Thomas Johann Seebeck. In 1806, Humphry Davy decomposed potash and soda, employing a voltaic pile of approximately 250 cells, showing that these substances were respectively the oxides of potassium and sodium, which metals previously had been unknown. Employing a battery of 2,000 elements of a voltaic