Search Results: Electronic 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...

This article documents and elaborates on the many critical behind-the-scenes events, unknown to the public, before the history leaves us. The author The bulk of the “the land between the two rivers” lies in what we call today the...

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...

Johannes Gutenberg (l. c. 1398-1468) was the inventor of the printing press (c. 1450) who seems to have developed the device from wine and oil presses of the time. Gutenberg’s printing press not only revolutionized book making but literally...

The Hawker Hurricane was a single-seat fighter plane, Britain's first monoplane, which fought in the Battle of Britain in the summer of 1940. Slower but more numerous than the Supermarine Spitfire, the Hurricane was used by the Royal Air...

Sumer was the southernmost region of ancient Mesopotamia (modern-day Iraq and Kuwait) which is generally considered the cradle of civilization. The name comes from Akkadian, the language of the north of Mesopotamia, and means “land of the...

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...

The Supermarine Spitfire was a single-seater fighter plane, one of the most important aircraft of the Second World War (1939-45). Employed by the Royal Air Force in such crucial encounters as the Battle of Britain in the summer of 1940, the...

Saint Valentine’s Day, or simply Valentine’s Day, is celebrated on the 14th of February, almost internationally but primarily in western societies. It is a commemorative Christian feast for some but a secular occasion for others who see it...