1800s
Events and trends
Technology
- Invention of the Jacquard loom in 1801.
- Ultraviolet radiation is discovered by Johann Wilhelm Ritter.
- Flag semaphore is gradually adopted by various navies of the world.
- Morphine is isolated from opium for the first time in 1804.
- Nicolas François Appert develops a method to preserve food by means of canning.
Astronomy
- The first known asteroids are discovered in this decade:
- Ceres (1801-01-01). Ceres is reclassified as a dwarf planet in 2006.
- Pallas (1802-03-28)
- Juno (1804-09-01)
- Vesta (1807-03-29)
War, peace and politics
World leaders