Non-Euclidean geometry that are both perpendicular to a third line: Euclidean geometry, named after the Greek mathematician Euclid, includes some of the oldest known mathematics, and geometries that deviated from this were not widely accepted as legitimate until the 19th century. The debate that eventually led to the discovery of the non-Euclidean geometries began almost as soon as Euclid's work "Elements" was written. In the "Elements", Euclid began with a limited number of assumptions (23 definitions, five common notions, and five postulates) and sought to prove all the other results (propositions) in the work. The most notorious of the postulates is often
In the Reign of Terror: The Adventures of a Westminster Boy In the Reign of Terror: The Adventures of a Westminster Boy In the Reign of Terror: The Adventures of a Westminster Boy is a novel by G. A. Henty published in 1888. The novel follows the adventures of Harry Sandwith, an English boy sent to live with the Marquis de St. Caux during the height of the French Revolution. Harry Sandwith, a sixteen-year-old English boy, is sent to live in France with the Marquis de St. Caux, a friend of a French nobleman Harry's father once served. The marquis is impressed with the English system of schooling and believes that