Search Results: Chebyshev filter

A terracotta ground water filter, in situ. 3rd century BCE, Greek Empuries (Emporion or Emporiae), Spain.

René Descartes (1596-1650) was a French mathematician, natural scientist, and philosopher, best known by the phrase 'Cogito ergo sum' ('I think therefore I am'). He published works on optics, coordinate geometry, physiology, and cosmology...

The Enlightenment (Age of Reason) was a revolution in thought in Europe and North America from the late 17th century to the late 18th century. The Enlightenment involved new approaches in philosophy, science, and politics. Above all, the...

Alchemy is an ancient practice aimed at recreating precious substances using recipes and transformative materials such as the philosopher's stone. Alchemists believed that materials like gold, silver, gems, and purple dye could be recreated...

The Fertile Crescent, often called the "Cradle of Civilization", is the region in the Middle East which curves, like a quarter-moon shape, from the Persian Gulf, through modern-day southern Iraq, Syria, Lebanon, Jordan, Israel and northern...

The Boston Tea Party was an act of political protest carried out by American colonists on 16 December 1773, in Boston, Massachusetts. Disguised as Mohawk Native Americans, the colonists dumped 342 crates of tea into Boston Harbor to protest...

Britain's integrated air defence system in the Second World War (1939-45), known as the Dowding System after the air chief marshal of that name, included code-breakers, radar stations, observers, searchlights, barrage balloons, anti-aircraft...

The War in the Vendée was a counter-revolutionary uprising that took place in the Vendée department of France from 1793 to 1796, during the French Revolution (1789-99). In response to the French Republic's attempts to impose conscription...

The Portuguese colonised Malacca (modern Melaka) on the southwest coast of the Malay peninsula from 1511 and kept it until 1641 when the Dutch took over. The port controlled the Malay Straits which lead from the Indian Ocean (the Andaman...

Empuries (also Emporiae or Emporion) was a Greek and then Roman colony on the northeastern coast of Spain. Thriving as a local and Mediterranean trading centre, it prospered from the 6th century BCE to the 2nd century CE. Several times the...