The pole has been the friend of navigators for millennia, beckoning compass needles from virtually every point on the planet.
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Turning Points This special report contains the fruits of our annual search for "turning points," the events, trends, inventions and ideas that will move the compass needles of our lives.
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Compass needles point towards the north magnetic pole, a point which has crept unpredictably from the coast of northern Canada a century ago to the middle of the Arctic Ocean, moving towards Russia.
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He is considered as the inventor of the prismatic compass, patented a year later by Charles Schmalcalder. He also studied compass needles, his Bakerian lectureOn the Best Kind of Steel and Form for a Compass Needle; Phil. Trans., 1821. containing the results of many experiments.
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1748.0030 The compass needles he produced as an instrument-maker were used by many contemporary magneticians. Around 1730, George loaned approximately £200 to John Harrison so that he could start work on his marine timekeeper known later as H1. George was commonly known in the trade as 'Honest George Graham'.
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The Man in Black explains to Desmond that people built wells looking for the source that made compass needles spin at points like this location. The Man in Black then throws Desmond down the well. Upon returning to his camp, Hurley's group arrives to talk to the Man in Black.
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"Terra Brasilis", Miller Atlas, 1519, French National Library. In 1517, King Manuel I of Portugal handed Lopo Homem a charter entitling him the privilege of certifying and amending all compass needles in vessels. This charter was revalidated in 1524 by King John III of Portugal. Anytime another person performed these tasks, they should have paid to the cartographer twenty cruzados.
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The phenomenon is especially important in aviation, as it causes the airplane's compass to give erroneous readings during banked turns and airspeed changes. The latter errors occur because the compass card tilts on its mount when under acceleration. Compass needles are often weighted during manufacture to compensate for magnetic dip, so that they will balance roughly horizontally. This balancing is latitude- dependent; see Compass balancing (magnetic dip).
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He demonstrated this to Tsar Alexander I in 1812, but Alexander declined to take it up. The Tsar went even further, and forbade all research and publications on electrical telegraphy for fear of the social changes it might bring about.Huurdeman, p. 54 When Schilling learned of Hans Christian Ørsted's discovery in 1820 that electric current could deflect compass needles, he decided to switch investigation into needle telegraphs, that is, telegraphs that used Ørsted's principle.
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NASA Science When a CME impacts the Earth's magnetosphere, it temporarily deforms the Earth's magnetic field, changing the direction of compass needles and inducing large electrical ground currents in Earth itself; this is called a geomagnetic storm and it is a global phenomenon. CME impacts can induce magnetic reconnection in Earth's magnetotail (the midnight side of the magnetosphere); this launches protons and electrons downward toward Earth's atmosphere, where they form the aurora.
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His work is particularly noted for containing the earliest detailed discussion of freely pivoting compass needles, a fundamental component of the dry compass soon to appear in medieval navigation.E. G. R. Taylor: “The South-Pointing Needle”, in: Imago Mundi, Vol. 8. (1951), pp. 1-7Barbara M. Kreutz, “Mediterranean Contributions to the Medieval Mariner's Compass,” Technology and Culture, Vol. 14, No. 3. (Jul., 1973), p. 371Frederic C. Lane, “The Economic Meaning of the Invention of the Compass,” The American Historical Review, Vol.
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As early as the 18th century, it was noticed that compass needles deviated near strongly magnetized outcrops. In 1797, Von Humboldt attributed this magnetization to lightning strikes (and lightning strikes do often magnetize surface rocks). In the 19th century studies of the direction of magnetization in rocks showed that some recent lavas were magnetized parallel to the Earth's magnetic field. Early in the 20th century, work by David, Brunhes and Mercanton showed that many rocks were magnetized antiparallel to the field.
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A single needle telegraph (1903) A needle telegraph is an electrical telegraph that uses indicating needles moved electromagnetically as its means of displaying messages. It is one of the two main types of electromagnetic telegraph, the other being the armature system as exemplified by the telegraph of Samuel Morse in the United States. Needle telegraphs were widely used in Europe and the British Empire during the nineteenth century. Needle telegraphs were suggested shortly after Hans Christian Ørsted discovered that electric currents could deflect compass needles in 1820.
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Gilbert deduced that the Earth's magnetic field is equivalent to that of a uniformly magnetized sphere, magnetized parallel to the axis of rotation (in modern terms, a geocentric axial dipole). However, he was aware that declinations were not consistent with this model. Based on the declinations that were known at the time, he proposed that the continents, because of their raised topography, formed centers of attraction that made compass needles deviate. He even demonstrated this effect by gouging out some topography on his terella and measuring the effect on declinations.
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Fish are abundant in the area, and shoals of sardines rise to the surface during the feeding times of larger fish. When this happens, the sea seems to bubble violently as if boiling, and, observed from a distance, the hissing sound produced by the fish flicking their tails on the water's surface adds to the impression. The stifling air wafted westerly on lazy breezes from the desert heightens the impression of extreme temperature, while the desert dust helps to create a mysterious darkness. Worse, the ferrous rocks make compass needles whirl erratically.
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The direction of magnetic field lines represented by iron filings sprinkled on paper placed above a bar magnet. Compass needles point in the direction of the local magnetic field, towards a magnet's south pole and away from its north pole. The field can be visualized by a set of magnetic field lines, that follow the direction of the field at each point. The lines can be constructed by measuring the strength and direction of the magnetic field at a large number of points (or at every point in space).
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Because the Earth's magnetic field's inclination and intensity vary at different latitudes, compasses are often balanced during manufacture so that the dial or needle will be level, eliminating needle drag which can give inaccurate readings. Most manufacturers balance their compass needles for one of five zones, ranging from zone 1, covering most of the Northern Hemisphere, to zone 5 covering Australia and the southern oceans. This individual zone balancing prevents excessive dipping of one end of the needle which can cause the compass card to stick and give false readings.Global compasses, MapWorld.
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They were considered the best cartographers of their time, with Emperor Charles V wanting them to work for him. In 1517 King Manuel I of Portugal handed Lopo Homem a charter giving him the privilege to certify and amend all compass needles in vessels. In the third phase of the former Portuguese nautical cartography, characterized by the abandonment of the influence of Ptolemy's representation of the East and more accuracy in the representation of lands and continents, stands out Fernão Vaz Dourado (Goa ~ 1520 – ~ 1580), giving him a reputation as one of the best cartographers of the time. Many of his charts are large scale.
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Illustration of magnetic dip from Norman's book, The Newe Attractive Magnetic dip, dip angle, or magnetic inclination is the angle made with the horizontal by the Earth's magnetic field lines. This angle varies at different points on the Earth's surface. Positive values of inclination indicate that the magnetic field of the Earth is pointing downward, into the Earth, at the point of measurement, and negative values indicate that it is pointing upward. The dip angle is in principle the angle made by the needle of a vertically held compass, though in practice ordinary compass needles may be weighted against dip or may be unable to move freely in the correct plane.
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Part of the carta marina of 1539 by Olaus Magnus, depicting the location of magnetic north vaguely conceived as "Insula Magnetū[m]" (Latin for "Island of Magnets"), off modern- day Murmansk. The man holding the rune staffs is the Norse hero Starkad ("Starcaterus"). Early European navigators, cartographers and scientists believed that compass needles were attracted to a hypothetical "magnetic island" somewhere in the far north (see Rupes Nigra), or to Polaris, the pole star.Early Concept of the North Magnetic Pole, Natural Resources Canada, retrieved June 2007 The idea that Earth itself acts as essentially a giant magnet was first proposed in 1600, by the English physician and natural philosopher William Gilbert.
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They were considered the best cartographers of their time, with Emperor Charles V wanting them to work for him. In 1517 King Manuel I of Portugal handed Lopo Homem a charter giving him the privilege to certify and amend all compass needles in vessels. In the third phase of the former Portuguese nautical cartography, characterized by the abandonment of the influence of Ptolemy's representation of the East and more accuracy in the representation of lands and continents, stands out Fernão Vaz Dourado (Goa ~ 1520 – ~ 1580), whose work has extraordinary quality and beauty, giving him a reputation as one of the best cartographers of the time. Many of his charts are large scale.
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110 The capsule is mounted in a transparent baseplate containing a direction-of-travel (DOT) indicator for use in taking bearings directly from a map. Cammenga air filled lensatic compass Other features found on modern orienteering compasses are map and romer scales for measuring distances and plotting positions on maps, luminous markings on the face or bezels, various sighting mechanisms (mirror, prism, etc.) for taking bearings of distant objects with greater precision, gimbal-mounted, "global" needles for use in differing hemispheres, special rare-earth magnets to stabilize compass needles, adjustable declination for obtaining instant true bearings without resorting to arithmetic, and devices such as inclinometers for measuring gradients.Johnson, pp. 110–111 The sport of orienteering has also resulted in the development of models with extremely fast-settling and stable needles utilizing rare-earth magnets for optimal use with a topographic map, a land navigation technique known as terrain association.
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