Dr. Liz
@drlizengineer
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Engineering and science through history. Aerospace engineer.
United States
Joined November 2019
"You have cost me more territory than all my enemies!" - this is a rather anecdotal phrase attributed to Louis XIV. However, it would be a very natural reaction to the results of a coastal survey showing that your country is about 20% smaller than previously thought. The survey
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A nice illustration of a lesser-known invention by Robert Hooke. The use of the camera obscura as a drawing aid was widespread in the 17th century and earlier. However, portable versions like this were less common.
THE 1694 STEADICAM ROBERT HOOKE (1635-1703) In 1694 Hooke presented a paper to the Royal Society and yet another Camera Obscura. This one was also (1st was in 1680) slightly cone shaped, and allowed the head and shoulders to be inserted. Illustration below from the Royal Society
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This map of the Isthmus of Suez comes from Napoleon's expedition to Egypt. It records an attempt to assess whether a canal could be built between the Mediterranean and the Red Sea. An ambitious project. Undermined by a surveying mistake. During the Napoleonic expedition to
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The inscription records Dariusâ achievement: "King Darius says: I am a Persian; setting out from Persia I conquered Egypt. I ordered to dig this canal from the river that is called Nile and flows in Egypt, to the sea that begins in Persia. Therefore, when this canal had been dug
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One of the best preserved is the Chalouf (Shaluf) Stela, carved in pink granite. It was found in 1866 during the construction of the modern Suez Canal and brought to scientific attention by Charles de Lesseps, son of Ferdinand de Lesseps. A fitting rediscovery, during the
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A navigable link between the Nile system and the Red Sea was created. Five stelae commemorating the canal were erected along its route in the Wadi Tumilat. Their inscriptions were written in Old Persian, Elamite, Babylonian, and Egyptian. 3/5
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Often called the âCanal of the Pharaohsâ, this waterway connected the Nile to the Red Sea via the Wadi Tumilat. The idea may date back to the 2nd millennium BC. Work began likely under Necho II in the late 7th century BC, and was later completed or restored under Darius I. 2/5
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This inscription records the opening of a canal between the Nile and the Red Sea. It was carved around 500 BC on the orders of Darius the Great to commemorate the project. An early precursor of the Suez Canal. (A thread đ§ľ) 1/5
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What you see here is a replica of one of the most powerful microscopes of the 17th century. It looks very simple - a tiny lens (often less than 2 mm in diameter) is mounted between two brass plates. The specimen was placed on a sharp pin in front of the lens. The pin could be
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The official aeronaut of Napoleon Bonaparte was a woman. Sophie Blanchard was the wife of the balloon pioneer Jean-Pierre Blanchard. After his death in 1809 she continued flying professionally, partly to support herself. She performed ceremonial ascents for imperial
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Early Sèvres porcelain relied on complex frit-based formulations rather than the kaolin system of hard-paste porcelain. I wrote a short note on this early Sèvres material here: https://t.co/dn3dV3CcOM
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This Sèvres biscuit porcelain figurine is remarkable for its sculptural refinement. Yet it was made from a material that made intricate sculpture particularly difficult to fire successfully. The figure is made from soft-paste porcelain (pâte tendre). This material was used at
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Huygens called the force vis centrifuga. He derived the relation geometrically. In modern notation it corresponds to F = m v² / r (or F = m Ď² r). Images: Horologium Oscillatorium (1673), BnF/Gallica.
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This book from 1673 is more than just a treatise on clocks. In Horologium Oscillatorium, Christiaan Huygens summarized several discoveries in theoretical mechanics made while studying the pendulum, including the correct relation for centrifugal force.
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One of the earliest literary references to a mechanical clock mechanism appears in an unexpected place. In his 1368 poem LâHorloge amoureux, Jean Froissart compares the mechanism of love to that of a clock, describing the loverâs heart as if it were regulated like a medieval
Before Huygens' pendulum clocks, medieval mechanical clocks in Europe were based on the verge and foliot escapement. This is a simple mechanism in which a rocking horizontal bar with weights controls a toothed escape wheel. Because of friction and large uncontrolled swings, these
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Three-barrel ribauldequins depicted in a scene from the Battle of Beverhoutsveld (1382) in the Froissart Chronicles. Image: Chroniques de Froissart, 15th-century manuscript, Staatsbibliothek zu Berlin (public domain).
This Leonardo drawing shows a 33-barrel "organ gun". It may look unusual, but the idea was not unrealistic. Multi-barrel weapons (ribauldequins) had been used in Europe since the 14th century. Leonardo arranged the barrels in three rotating rows. One row could fire while the
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The model in this masterpiece may have been a pioneer of microscopy. Antonie van Leeuwenhoek was Vermeerâs contemporary in Delft and later served as executor of his estate. He began as a draper and land surveyor but became famous for his groundbreaking microscope observations,
#UnJourUneOeuvre/#WorkOfTheDay đŤđˇ Ce savant, peint par Johannes Vermeer en 1668, vous accueille dans lâintimitĂŠ de son cabinet de travail, bercĂŠ par une lumière douce et latĂŠrale. La main tendue vers le globe cĂŠleste, lâastronome est vĂŞtu dâune ample robe vert foncĂŠ et semble
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This Leonardo drawing shows a 33-barrel "organ gun". It may look unusual, but the idea was not unrealistic. Multi-barrel weapons (ribauldequins) had been used in Europe since the 14th century. Leonardo arranged the barrels in three rotating rows. One row could fire while the
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The author of this famous unsolved cipher, Alexander DâAgapeyeff, had quite an unusual life. Born in Russia in 1902, he served with British forces during the Russian Civil War. Later he became a cartographer, and was in the RAF during WWII. Yet he is remembered today mostly for
In 1939, Alexander d'Agapeyeff included a cipher challenge on the last page of his book "Codes and Ciphersâ. 87 years later, it remains unsolved. He later admitted he had forgotten how he encrypted it
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One of the best-known operators of the âMechanical Turkâ was William Schlumberger, a chess master from Alsace. In 1827 in Baltimore, the heat inside the cabinet forced him to climb out. Two boys saw this from a nearby rooftop. The story soon reached the newspapers.
This engraving of the famous âMechanical Turkâ appears quite often as an illustration of the chess automaton hoax. What is rarely mentioned, however, is that this engraving probably does not show how the operator actually sat inside. The âTurkâ was created by Wolfgang von
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