The 1670s: microscopes, starlight and a new observatory

The decade opened up two new worlds: the very small and the very far. In the Dutch city of Delft, the cloth merchant Antonie van Leeuwenhoek built tiny, powerful lenses. In letters to the Royal Society from 1676, he described 'animalcules' in drops of water, the first known observations of bacteria and other microorganisms.

In 1676 the Danish astronomer Ole Rømer, working in Paris, noticed that the eclipses of Jupiter's moon Io came earlier or later depending on Earth's distance from Jupiter. He concluded that light does not travel instantly, a key discovery for physics.

In 1675 King Charles II founded the Royal Observatory at Greenwich to improve star charts for navigation. Centuries later, Greenwich would give the world its prime meridian and Greenwich Mean Time.

Timekeeping itself improved. The Dutch scientist Christiaan Huygens developed the balance spring for watches around 1675, making pocket watches far more accurate. Trade grew too: the Hudson's Bay Company, chartered in 1670, became one of the oldest companies in the world.