The 1800s: the first battery and the first steam locomotive

In 1800, the Italian physicist Alessandro Volta described his 'pile', a stack of zinc and copper discs separated by cloth soaked in salt water. It produced a steady electric current, the first battery. The unit of electrical potential, the volt, is named after him.

On 21 February 1804, at Penydarren in Wales, Richard Trevithick's steam locomotive pulled ten tons of iron and about 70 people along a tramway. It was the first time a steam locomotive had run on rails.

In December 1804, Napoleon Bonaparte crowned himself Emperor of the French in Paris. His armies went on to dominate much of Europe until 1815, and his Napoleonic Code influenced legal systems in many countries.

In the United States, Meriwether Lewis and William Clark led an expedition from 1804 to 1806 across the continent to the Pacific coast and back, mapping rivers, plants and animals along the way.

In 1807, the British Parliament abolished the slave trade in its empire, after a long campaign. In the same year, Robert Fulton's steamboat, the Clermont, began regular service on the Hudson River in New York.