"This basically turns the entire satellite into a compass needle, allowing you to align it with Earth's magnetic field for steering," Manchester said.
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The north magnetic pole, the point on the Earth where a compass needle would point down, is sliding about 35 miles closer to Russia each year.
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The north magnetic pole, the point on the Earth where a compass needle would point down, is sliding about 21975 miles closer to Russia each year.
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Your own answer to the question is something of a parental compass needle too, pointing the way when you are unsure how to parent in a given situation.
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You would pull out your handy compass, or more likely your compass app (yes, they have an app for that), and you would see that the compass needle points to the True North.
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" She saved her highest praise for animals that defend themselves in exceptional ways: the ostrich, for example, "whose comic duckling head on its / great neck, revolves with compass- / needle nervousness / when he stands guard.
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Museum Review WASHINGTON — On a late summer day in 1963, 200,21956 Americans made the Washington Monument the compass needle for a new direction in history, up and forward, when they gathered at its base, then marched a mile or so on to hear the Rev.
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Or perhaps it would be more apt to say that I have been at a loss —a strange turn of phrase, as if loss were a place in the physical world, a kind of reverse oasis or Bermuda Triangle where the spirit fails and the compass needle spins.
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Norman also created a dip circle, a compass needle pivoted about a horizontal axis, to measure the effect.
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The Suunto Global Needle System acquired from Recta as the Turbo-20 needle design, the conventional magnetized compass needle is not used.Morton, Keith, Planning a Wilderness Trip in Canada and Alaska, ,(1997), p. 110 Instead, the compass needle and magnet are built as separate units functioning independently from each other. The needle itself is fixed at its pivot by means of a double bearing, while the magnet rotates on a pivot with its own jeweled bearing.
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If the needle tilts to one direction, tilt the compass slightly and gently to the opposing direction until the compass needle is horizontal, lengthwise. Items to avoid around compasses are magnets of any kind and any electronics. Magnetic fields from electronics can easily disrupt the needle, preventing it from aligning with the Earth's magnetic fields, causing inaccurate readings. The Earth's natural magnetic forces are considerably weak, measuring at 0.5 gauss and magnetic fields from household electronics can easily exceed it, overpowering the compass needle.
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The magnetic meridian is an equivalent imaginary line connecting the magnetic south and north poles and can be taken as the horizontal component of magnetic force lines along the surface of the earth. Therefore, a compass needle will be parallel to the magnetic meridian. However, a compass needle will not be steady in the magnetic meridian, because of the longitude from east to west being complete geodesic. The angle between the magnetic and the true meridian is the magnetic declination, which is relevant for navigating with a compass.
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In 1600, William Gilbert proposed, in his De Magnete, that electricity and magnetism, while both capable of causing attraction and repulsion of objects, were distinct effects. Mariners had noticed that lightning strikes had the ability to disturb a compass needle. The link between lightning and electricity was not confirmed until Benjamin Franklin's proposed experiments in 1752. One of the first to discover and publish a link between man-made electric current and magnetism was Gian Romagnosi, who in 1802 noticed that connecting a wire across a voltaic pile deflected a nearby compass needle.
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This method is based on the observation that a compass needle does not in general point exactly north. The angle between true north and the direction of the compass needle (magnetic north) is called the magnetic declination or variation, and its value varies from place to place. Several writers proposed that the size of magnetic declination could be used to determine longitude. Mercator suggested that the magnetic north pole was an island in the longitude of the Azores, where magnetic declination was, at that time, close to zero.
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The deflection of a magnetic compass needle by the current in a wire was first described by Hans Christian Ørsted in 1820. The phenomenon was studied both for its own sake and as a means of measuring electric current.
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Iron filings that have oriented in the magnetic field produced by a bar magnet Detecting magnetic field with compass and with iron filings The magnetic flux density (also called magnetic B field or just magnetic field, usually denoted B) is a vector field. The magnetic B field vector at a given point in space is specified by two properties: # Its direction, which is along the orientation of a compass needle. # Its magnitude (also called strength), which is proportional to how strongly the compass needle orients along that direction. In SI units, the strength of the magnetic B field is given in teslas.
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In the image to the left, the bezel's N has been aligned with the direction indicated by the magnetic end of the compass needle, reflecting a magnetic declination of 0 degrees. The arrow on the base plate indicates a bearing of 312 degrees.
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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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It is not clear what the speakers at the conference meant by "perfect alignment with the North Magnetic Pole". As the geomagnetic field of the earth continuously changes the deviation of the compass needle from true north (known as the magnetic declination) also slowly changes. In the past there were epochs when the compass needle at Mecca pointed true north (and there will be future epochs when this is true again) but at the moment the line of no compass deviation is located somewhat to the southeast of Mecca. In 2015 the (predicted) magnetic declination of Mecca is 3.3° East and will continue to increase at about +0.06° per year.
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The versorium needle also responds identically regardless of the polarity of the attracting charge, so it cannot distinguish between a positive and a negative charge, unlike a compass needle, which has a "North" and "South" end which can distinguish between the "North" and "South" pole of a magnet.
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Magnetic declination from true north in 2000. Historically, the magnetic compass was an important tool for navigation. While it has been widely replaced by Global Positioning Systems, many airplanes and ships still carry them, as do casual boaters and hikers. The direction in which a compass needle points is known as magnetic north.
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However, it was not until the time of Shen Kuo that the earliest magnetic compasses would be used for navigation. In his written work, Shen Kuo made the first known explicit reference to the magnetic compass-needle and the concept of true north.Needham (1986), Volume 4, Part 1, 249–250.Hsu (1988), 102.
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Space physics can be traced to the Chinese who discovered the principle of the compass, but did not understand how it worked. During the 16th century, in De Magnete, William Gilbert gave the first description of the Earth's magnetic field, showing that the Earth itself is a great magnet, which explained why a compass needle points north. Deviations of the compass needle magnetic declination were recorded on navigation charts, and a detailed study of the declination near London by watchmaker George Graham resulted in the discovery of irregular magnetic fluctuations that we now call magnetic storms, so named by Alexander Von Humboldt. Gauss and William Weber made very careful measurements of Earth's magnetic field which showed systematic variations and random fluctuations.
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All subsequent reissues used the modified jacket, but when it was re-released as a MEG-CD in September 2016, it was returned to its original position. At the same time, the motif of the compass needle that was printed on the lower left of the first press of the record was also revived.
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Norman demonstrated magnetic dip by creating a compass needle that pivoted on a horizontal axis. The needle tilted at a steep angle relative to the horizon line. Magnetic inclination and local variations were known before Robert Norman, but his pamphlet had a greater influence than the earlier work. The crater Norman on the Moon is named in his honour.
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Thomson mirror galvanometer, patented in 1858. Originally, the instruments relied on the Earth's magnetic field to provide the restoring force for the compass needle. These were called "tangent" galvanometers and had to be oriented before use. Later instruments of the "astatic" type used opposing magnets to become independent of the Earth's field and would operate in any orientation.
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Example of magnetic declination showing a compass needle with a "positive" (or "easterly") variation from geographic north. Ng is geographic or true north, Nm is magnetic north, and δ is magnetic declination Magnetic declination, or magnetic variation, is the angle on the horizontal plane between magnetic north (the direction the north end of a magnetized compass needle points, corresponding to the direction of the Earth's magnetic field lines) and true north (the direction along a meridian towards the geographic North Pole). This angle varies depending on position on the Earth's surface and changes over time. Somewhat more formally, Bowditch defines variation as “the angle between the magnetic and geographic meridians at any place, expressed in degrees and minutes east or west to indicate the direction of magnetic north from true north.
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To undertake this task, he walked the diocese with a quadrant, a compass needle and a sundial to establish distances and angles. The chronicles he kept until 1630 probably date from this time as well. He also chronicled a journey to Rome that he undertook in 1593 on the bishop's instruction. In March 1599, Henri IV named him almoner in ordinary.
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There are twelve (12) gates hanging from the wall of the New City of Jerusalem. These 12 gates are oriented in groups of three and face the four cardinal directions of the compass needle: the north, south, east and west. There is an angel at each gate, residing in a gatehouse. The 12 gates are each made of a 'single' pearl, giving these the name "pearly gates".
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132–133, Joseph Henry Press, 2004 Thomson's design was able to detect very rapid current changes by using small magnets attached to a lightweight mirror, suspended by a thread, instead of a compass needle. The deflection of a light beam on the mirror greatly magnified the deflection induced by small currents. Alternatively, the deflection of the suspended magnets could be observed directly through a microscope.
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Illustration of Versorium construction The versorium is a needle constructed out of metal which is allowed to pivot freely on a pedestal. It is similar to a compass needle, but unmagnetized. The needle is attracted to charged bodies brought near it, turning towards the charged object.Electroscopes Since it is able to distinguish between charged and non- charged objects, it is an example of a class of devices known as electroscopes.
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First Class emblem Scouting uses a series of medals and patches as emblems. The badge for the Scout rank consists of a simple fleur-de-lis, which symbolizes a compass needle. The needle points the Scout in the right direction, which is onward and upward. The Tenderfoot badge takes the fleur-de-lis of the Scout badge and adds two stars and an eagle with an American shield.
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Robert Norman is noted for The Newe Attractive, a pamphlet published in 1581Published in London by Ballard. See describing the lodestone (magnet) and practical aspects of navigation. More importantly, it included Norman's measurement of magnetic dip, the incline at an angle from the horizon by a compass needle discovered by Georg Hartmann in 1544. This effect is caused by the Earth's magnetic field not running parallel to the planet's surface.
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The galvanometer is oriented so that the plane of the coil is vertical and aligned along parallel to the horizontal component of the Earth's magnetic field (i.e. parallel to the local "magnetic meridian"). When an electric current flows through the galvanometer coil, a second magnetic field is created. At the center of the coil, where the compass needle is located, the coil's field is perpendicular to the plane of the coil.
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These theories of electricity and magnetism were thought of as two separate phenomena, until Hans Christian Ørsted noticed that a compass needle would deflect from magnetic north when placed near an electric current. This caused him to develop theories that electricity and magnetism were interrelated and could affect one another. Ørsted's work was the basis for a theory by French physicist André-Marie Ampère, which unified the relation between magnetism and electricity.
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Magnetosomes are membranous structures present in magnetotactic bacteria (MTB). They contain iron-rich magnetic particles that are enclosed within a lipid bilayer membrane. Each magnetosome can often contain 15 to 20 magnetite crystals that form a chain which acts like a compass needle to orient magnetotactic bacteria in geomagnetic fields, thereby simplifying their search for their preferred microaerophilic environments. Recent research has shown that magnetosomes are invaginations of the inner membrane and not freestanding vesicles.
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The galvanometer was made possible in 1820 by the discovery by Hans Christian Ørsted that electric currents would deflect a compass needle, and the gold- leaf electroscope was even earlier (Abraham Bennet, 1786).Keithley, p. 36 Yet Golding Bird could still write in 1848 that "the irritable muscles of a frog's legs were no less than 56,000 times more delicate a test of electricity than the most sensitive condensing electrometer."Bird, p.
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Schilling's telegraph is one of a type called needle telegraphs. These are telegraphs that use a coil of wire as an electromagnet to deflect a small magnet shaped like a compass needle. The position of the needle imparts the telegraphed information to the person receiving the message. Schilling's 1832 demonstration telegraph in St. Petersburg used six wires for signalling, one wire for calling, and a common return, making eight wires in all.
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He devised a novel method of fidding a topgallant mast and several contrivances for the "better nipping and stopping a cable". He designed a long catamaran for forming a life raft and a form of floating sea anchor, or drogue anchor (he called it a "propeller") like an umbrella. He created a set of signals, that could be seen from all angles, using shapes instead of flags. He also suggested using a floating compass needle to find North.
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Isoclinic lines for the year 2015. Magnetic dip results from the tendency of a magnet to align itself with lines of magnetic field. As the Earth's magnetic field lines are not parallel to the surface, the north end of a compass needle will point downward in the northern hemisphere (positive dip) or upward in the southern hemisphere (negative dip). The range of dip is from -90 degrees (at the North Magnetic Pole) to +90 degrees (at the South Magnetic Pole).
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He had realized the normal magnetic compass would not furnish accurate readings owing to the large iron ore deposits of the area. The compass needle was magnetized and would point in the direction of a large iron deposit, which generally was in a northerly direction. That idea was fine except where there were vast deposits of iron all around a local land territory. This was the case in the Upper Peninsula of Michigan, so the magnetic compass was completely useless there.
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Compasses are used to determine the direction of true North. However, the compass reading must be corrected for two effects. The first is magnetic declination or variation—the angular difference between magnetic North (the local direction of the Earth's magnetic field) and true North.Admiralty Manual of Navigation Vol 1 1964 p12 The second is magnetic deviation—the angular difference between magnetic North and the compass needle due to nearby sources of interference such as magnetically permeable bodies, or other magnetic fields within the field of influence.
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However, instead of always pointing toward the same direction—the animals are asleep and thus immobile—the neuronal "compass needle" moves constantly. In particular, during rapid eye movement sleep, a brain state rich in dreaming activity in humans and whose electrical activity is virtually indistinguishable from the waking brain, this directional signal moves as if the animal is awake: that is, HD neurons are sequentially activated, and the individual neurons representing a common direction during wake are still active, or silent, at the same time.
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Pivoting compass needle in a 14th-century handcopy of Peter's Epistola de magnete (1269) Petrus Peregrinus de Maricourt (Latin), Pierre Pelerin de Maricourt (French), or Peter Peregrinus of MaricourtEdward Grant, “Peter Peregrinus,” Dictionary of Scientific Biography (New York: Scribners, 1975), 10: 532. Ron B. Thomson, “Peter Peregrinus,” Medieval Science, Technology and Medicine. An Encyclopedia, ed. Thomas Glick et al. (New York and London: Routledge, 2005), pp. 388-389. (fl. 1269), was a 13th-century French scholar who conducted experiments on magnetism and wrote the first extant treatise describing the properties of magnets.
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L'Agulhas is the most southern coastal village and holiday resort in Africa, located within the Cape Agulhas Local Municipality at the southernmost tip of the African mainland. It is situated next to the town of Struisbaai and about south of the regional centre of Bredasdorp. The name "Agulhas", Portuguese for "needles", is said to have been given to the cape because the compass-needle was seen to point due north, that is, with no magnetic deviation. The Agulhas Bank is reputed to be the richest fishing area in the Southern Hemisphere.
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Shearwater Perdix and Ratio iX3M GPS dive computers in compass mode Shearwater Perdix and Ratio iX3M GPS dive computers in compass mode with Suunto SK7 magnetic compass in close proximity Flux-gate compasses are built into several models of dive computer as an extra function. They may require calibration when powered up, but calibration usually lasts as long as the processor is running. They are usually insensitive to tilt as there are no moving parts to jam. The display varies, and may not be as intuitive as for a mechanical compass needle or card arrangement.
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Data is stored in the magnetic media, such as hard drives, floppy disks, and magnetic tape, by making very small areas called magnetic domains, change their magnetic alignment to be in the direction of an applied magnetic field. This phenomenon occurs in much the same way a compass needle points in the direction of the Earth's magnetic field. Degaussing, commonly called erasure, leaves the domains in random patterns with no preference to orientation, thereby rendering previous data unrecoverable. There are some domains whose magnetic alignment is not randomized after degaussing.
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This error is eliminated while accelerating or decelerating on a heading of exactly North or exactly South. Second, when on a northerly heading and a turn towards the east or west is made, the magnet causes the compass to lag behind the actual heading the aircraft is flying through. This lag will slowly diminish as the aircraft approaches either east or west and will be approximately correct when on an east or west heading. When the aircraft turns further towards South, the magnetic compass needle will tend to lead the actual heading of the aircraft.
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Born in Corringham, a small civil parish in Lincolnshire, he was educated at Leeds Grammar School and Magdalen Hall, Oxford. He was awarded a BA in October 1736, MA in June 1739 and MB in February 1742, after which he lived in London as a practising physician. In 1745, Knight discovered a process for forming strongly magnetized steel, which he used to develop a compass needle able to function with greater precision. He was elected a Fellow of the Royal Society the same year after presenting his findings to the Society.
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During the Second World War, Bitter worked for the Naval Bureau of Ordnance. He often traveled to England to find ways to demagnetize British ships to protect them from a new type of German mine, which used a compass needle to trigger detonation. The mine, dropped from the air, would sink to the bottom of a river and remain there with its magnetic needle aligned to the Earth's magnetic field at that location. When a ship passed over it, the mass of the ship caused the magnetic needle to move slightly.
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By 1808 John Dalton had discovered that atoms of different elements have different weights and proposed the modern theory of the atom. It was Hans Christian Ørsted who first proposed the connection between electricity and magnetism after observing the deflection of a compass needle by a nearby electric current. By the early 1830s Michael Faraday had demonstrated that magnetic fields and electricity could generate each other. In 1864 James Clerk Maxwell presented to the Royal Society a set of equations that described this relationship between electricity and magnetism.
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Barlow investigated a suggestion made by André-Marie Ampère in 1820 that an electromagnetic telegraph could be made by deflecting a compass needle with an electric current. In 1824 Barlow proclaimed the idea impractical after he found that the effect on the compass seriously diminished "with only 200 feet of wire". Barlow, and other eminent scientists of the time who agreed with him, are criticised for retarding the development of the telegraph. A decade passed between Ampère's paper being read at the Paris Academy of Sciences and William Ritchie building the first demonstration electromagnetic telegraph.
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A grid compassCAA Advisory circular known as well as grid steering compass, is a navigating instrument. It is a design of magnetic compass that facilitates steering a steady course without the risk of parallax error. The grid compass is the simplest steering compass from the pilot's or helmsman's point of view, because he doesn't need to watch the number (or the division mark) of the wanted course. He has only to steer the craft so that the N/S compass needle lies parallel between the lines of the overlay disc.
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Using the right hand rule to find the direction of the magnetic field The direction of the magnetic field at a point, the direction of the arrowheads on the magnetic field lines, which is the direction that the "north pole" of the compass needle points, can be found from the current by the right-hand rule. If the right hand is wrapped around the wire so the thumb points in the direction of the current (conventional current, flow of positive charge), the fingers will curl around the wire in the direction of the magnetic field.
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Exposure to strong magnets, or magnetic interference can sometimes cause the magnetic poles of the compass needle to differ or even reverse. Avoid iron rich deposits when using a compass, for example, certain rocks which contain magnetic minerals, like Magnetite. This is often indicated by a rock with a surface which is dark and has a metallic luster, not all magnetic mineral bearing rocks have this indication. To see if a rock or an area is causing interference on a compass, get out of the area, and see if the needle on the compass moves.
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Location of the North Magnetic Pole and the North Geomagnetic Pole in 2017. The North Magnetic Pole is a point on the surface of Earth's Northern Hemisphere at which the planet's magnetic field points vertically downwards (in other words, if a magnetic compass needle is allowed to rotate about a horizontal axis, it will point straight down). There is only one location where this occurs, near (but distinct from) the Geographic North Pole. The Geomagnetic North Pole a related point, is the pole of an ideal dipole model of the Earth's magnetic field that most closely fits the Earth's actual magnetic field.
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The Wujing Zongyao part 1 volume 15 text stated: Later on in the Song dynasty the compass was used with maritime navigation. Several decades after the Wujing Zongyao was written, the scientist and statesman Shen Kuo (1031–1095 AD) wrote of the first truly magnetized compass needle in his book Dream Pool Essays (1088 AD). With a more efficient compass magnetized by lodestone, the thermoremanence compass fell out of use. The later maritime author Zhu Yu wrote of the magnetic needle compass as a means to navigate at sea in his Pingzhou Table Talks of 1119 AD.
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Grid north (GN) is a navigational term referring to the direction northwards along the grid lines of a map projection. It is contrasted with true north (the direction of the North Pole) and magnetic north (the direction in which a compass needle points). Many topographic maps, including those of the United States Geological Survey and Great Britain's Ordnance Survey, indicate the difference between grid north, true north, and magnetic north. The grid lines on Ordnance Survey maps divide the UK into one-kilometre squares, east of an imaginary zero point in the Atlantic Ocean, west of Cornwall.
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Map showing the location of Cape Agulhas relative to the Cape of Good Hope. Cape Agulhas is located in the Overberg region, 170 kilometres (105 mi) southeast of Cape Town. The cape was named by Portuguese navigators, who called it Cabo das Agulhas—Portuguese for "Cape of Needles"—after noticing that around the year 1500 the direction of magnetic north (and therefore the compass needle) coincided with true north in the region.Patricia Seed: Discovery of the Coincidence of Magnetic and True North The cape is within the Cape Agulhas Local Municipality in the Overberg District of the Western Cape province of South Africa.
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The true meridian is the chord that goes from one pole to the other, passing through the observer, and is contrasted with the magnetic meridian, which goes through the magnetic poles and the observer. The true meridian can be found by careful astronomical observations, and the magnetic meridian is simply parallel to the compass needle. The arithmetic difference between the true and magnetic meridian is called the magnetic declination, which is important for the calibration of compasses. Henry D. Thoreau classified this true meridian versus the magnetic meridian in order to have a more qualitative, intuitive, and abstract function.
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In 1750 Michell published at Cambridge a work of some eighty pages entitled "A Treatise of Artificial Magnets", in which he presented an easy and expeditious method of producing magnets that are superior to the best natural magnets. Besides the description of the method of magnetization which still bears his name, this work contains a variety of accurate observations about magnetism, and features a lucid exposition of the nature of magnetic induction. At one point, Michell attempted to measure the radiation pressure of light by focusing sunlight onto one side of a compass needle. The experiment was not a success: the needle melted.
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As he was setting up his materials, he noticed a compass needle deflected away from magnetic north when the electric current from the battery he was using was switched on and off. This deflection convinced him that magnetic fields radiate from all sides of a wire carrying an electric current, just as light and heat do, and that it confirmed a direct relationship between electricity and magnetism. At the time of discovery, Ørsted did not suggest any satisfactory explanation of the phenomenon, nor did he try to represent the phenomenon in a mathematical framework. However, three months later he began more intensive investigations.
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The field at the surface of the Earth is approximately the same as if a giant bar magnet were positioned at the center of the Earth and tilted at an angle of about 11° off the rotational axis of the Earth (see the figure). The north pole of a magnetic compass needle points roughly north, toward the North Magnetic Pole. However, because a magnetic pole is attracted to its opposite, the North Magnetic Pole is actually the south pole of the geomagnetic field. This confusion in terminology arises because the pole of a magnet is defined by the geographical direction it points.
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Minnesota was admitted as the 32nd U.S. state on May 11, 1858, and Deerwood (originally named Withington), was the first Cuyuna Range community, settled in 1882. The discovery of the Cuyuna Iron Range was an accident, made by the chance observation of a compass needle irregularity while surveyor and mining engineer Cuyler Adams was exploring the area with his St. Bernard, named "Una". Adams surmised that a large, underground body of iron ore might be responsible for the discrepancy. Nearly fifteen years after meticulously mapping these compass deflections, test drilling by Adams in May 1903 resulted in the discovery of manganiferous ore near Deerwood.
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Magnetotactic bacteria are widespread, motile, diverse prokaryotes that biomineralize a unique organelle called the magnetosome. A magnetosome consists of a nano-sized crystal of a magnetic iron mineral, which is enveloped by a lipid bilayer membrane. In the cells of most all magnetotactic bacteria, magnetosomes are organized as well-ordered chains. The magnetosome chain causes the cell to behave as a motile, miniature compass needle where the cell aligns and swims parallel to magnetic field lines. The magnetic dipole moment of the cell is often large enough that its interaction with Earth’s magnetic field overcomes the thermal forces that tend to randomize the orientation of the cell in its aqueous surroundings.
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Ice in the Ross Sea (the small black objects are seals) On 6 March the crew sighted distant land, about 65 km (40 miles) to the south-east – the peaks of the Admiralty Range in Victoria Land. As they drew nearer, expectations of a landing grew; on 8 March Kainan Maru stood off Dorset Point, but ice conditions made it impossible to get nearer to the shore. The ship sailed on, past the Possession Islands and towards Coulman Island, where ice conditions were even worse. To their further discomfort, their proximity to the South Magnetic Pole was causing violent disturbances to the compass needle.
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Penn Station terminal service plant in New York City The relation between electric current, magnetic fields and physical forces was first noted by Hans Christian Ørsted in 1820, who observed a compass needle was deflected from pointing North when a current flowed in an adjacent wire. The tangent galvanometer was used to measure currents using this effect, where the restoring force returning the pointer to the zero position was provided by the Earth's magnetic field. This made these instruments usable only when aligned with the Earth's field. Sensitivity of the instrument was increased by using additional turns of wire to multiply the effect – the instruments were called "multipliers".
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William Gilbert's terrella William Gilbert, the royal physician to Queen Elizabeth I, devoted much of his time, energy and resources to the study of the Earth's magnetism. It had been known for centuries that a freely suspended compass needle pointed north. Earlier investigators (including Christopher Columbus) found that direction deviated somewhat from true north, and Robert Norman showed the force on the needle was not horizontal but slanted into the Earth. William Gilbert's explanation was that the Earth itself was a giant magnet, and he demonstrated this by creating a scale model of the magnetic Earth, a "terrella", a sphere formed out of a lodestone.
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At this time Spanish inventor Isaac Peral designed and built the first submarine capable of navigating underwater with a decent level of control and with the ability to launch torpedoes both submerged and on the surface. This was the first proper submarine, solving the problems of propulsion, stability and armament all at once. Peral's submarine was driven by electric propulsion, and had a periscope, target practice apparatus, compensating compass needle, gyroscope, sliding electric torpedo tube launcher and servomotor (to maintain the stability and the trim of the ship in all circumstances). Zaharoff found out within no time about this young Spanish Naval officer's invention.
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The needle of the compass is then freed by using the side button, and allowed to spin until the damping action slows its movement, and then stabilises. The side button is released and the needle is then firmly held in place, allowing the user thereafter to conveniently read the orientation measured. One first reads the scale that shows the angle subtended by the lid of the compass, and then depending on the colour shown (red or black) the end of the compass needle with the corresponding colour. Data are then recorded as (for example) 25°->333° (dip and dip-direction) or (plunge and plunge-direction).
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In this work he describes many of his experiments with his model earth called the terrella. From his experiments, he concluded that the Earth was itself magnetic and that this was the reason compasses pointed north (previously, some believed that it was the pole star (Polaris) or a large magnetic island on the north pole that attracted the compass). An understanding of the relationship between electricity and magnetism began in 1819 with work by Hans Christian Ørsted, a professor at the University of Copenhagen, who discovered by the accidental twitching of a compass needle near a wire that an electric current could create a magnetic field. This landmark experiment is known as Ørsted's Experiment.
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Diagram of a Ming Dynasty mariner's compass In terms of global significance, Zhu Yu's book was the first book in history to mention the use of the mariner's magnetic-needle compass for navigation at sea.Sivin, III, 22. Although the compass needle was first described in detail by the Chinese scientist Shen Kuo (1031–1095) in his Dream Pool Essays of 1088 AD, he did not specifically outline its use for navigation at sea. The passage from Zhu Yu's Pingzhou Ketan relating to the use of the compass states: > According to government regulations concerning seagoing ships, the larger > ones can carry several hundred men, and the smaller ones may have more than > a hundred men on board.
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WAGGGS membership badge Miss Kari Aas designed the World Trefoil emblem that was adopted at the World Conference in 1930, a gold trefoil on a blue background. The three leaves represent the three duties and the three parts of the promise, the two five point-stars stand for the promise and the law and the vein in the centre represents the compass needle showing the right way. The base of the trefoil stands for the flame of the love of humanity and the colours blue and gold represent the sun shining over all children in the world. The World Badge, incorporating the trefoil, was first adopted at the 11th World Conference in Evian, France in 1946.
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The most important nautical innovation of the Song period seems to have been the introduction of the magnetic mariner's compass, which permitted accurate navigation on the open sea regardless of the weather. The magnetized compass needle known in Chinese as the "south-pointing needle" was first described by Shen Kuo in his 1088 Dream Pool Essays and first mentioned in active use by sailors in Zhu Yu's 1119 Pingzhou Table Talks. A plan and side view of a canal pound lock, a concept pioneered in 984 by the Assistant Commissioner of Transport for Huainan, the engineer Qiao Weiyo. There were other considerable advancements in hydraulic engineering and nautical technology during the Song dynasty.
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In the past, electrically charged objects were thought to produce two different, unrelated types of field associated with their charge property. An electric field is produced when the charge is stationary with respect to an observer measuring the properties of the charge, and a magnetic field as well as an electric field is produced when the charge moves, creating an electric current with respect to this observer. Over time, it was realized that the electric and magnetic fields are better thought of as two parts of a greater whole—the electromagnetic field. Until 1820, when the Danish physicist H. C. Ørsted showed the effect of electric current on a compass needle, electricity and magnetism had been viewed as unrelated phenomena.
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In 1730, Celsius published the (New Method for Determining the Distance from the Earth to the Sun). His research also involved the study of auroral phenomena, which he conducted with his assistant Olof Hiorter, and he was the first to suggest a connection between the aurora borealis and changes in the magnetic field of the Earth. He observed the variations of a compass needle and found that larger deflections correlated with stronger auroral activity. At Nuremberg in 1733, he published a collection of 316 observations of the aurora borealis made by himself and others over the period 1716–1732. Celsius traveled frequently in the early 1730s, including to Germany, Italy and France, when he visited most of the major European observatories.
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The crew did a good job, but its chief forgot one thing – > the fact that a compass needle points to magnetic, not true north. In this > area the angle of declination is about four degrees, a significant source of > error on a seven-mile [11 km] front ... An experienced Virginia surveyor, in > checking the data, discovered the error but said nothing about it. > Presently, however, when the sale was being concluded and the deeds > recorded, he brought the error to light, and under a sort of "doctrine of > vacancy" claimed the wedge of land left by a corrected survey. His title was > established, and he and his heirs found themselves owner of a seven-mile > strip of forest, aggregating almost .
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However, this term is misleading in that every other application of the term taxis involves a stimulus-response mechanism. In contrast to the magnetoreception of animals, the bacteria contain fixed magnets that force the bacteria into alignment—even dead cells are dragged into alignment, just like a compass needle. Marine environments are generally characterized by low concentrations of nutrients kept in steady or intermittent motion by currents and turbulence. Marine bacteria have developed strategies, such as swimming and using directional sensing–response systems, to migrate towards favorable places in the nutrient gradients. Magnetotactic bacteria utilize Earth’s magnetic field to facilitate downward swimming into the oxic–anoxic interface, which is the most favorable place for their persistence and proliferation, in chemically stratified sediments or water columns.
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A tangent galvanometer can also be used to measure the magnitude of the horizontal component of the geomagnetic field. When used in this way, a low-voltage power source, such as a battery, is connected in series with a rheostat, the galvanometer, and an ammeter. The galvanometer is first aligned so that the coil is parallel to the geomagnetic field, whose direction is indicated by the compass when there is no current through the coils. The battery is then connected and the rheostat is adjusted until the compass needle deflects 45 degrees from the geomagnetic field, indicating that the magnitude of the magnetic field at the center of the coil is the same as that of the horizontal component of the geomagnetic field.
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To take a map bearing or true bearing (a bearing taken in reference to true, not magnetic north) to a destination with a protractor compass, the edge of the compass is placed on the map so that it connects the current location with the desired destination (some sources recommend physically drawing a line). The orienting lines in the base of the compass dial are then rotated to align with actual or true north by aligning them with a marked line of longitude (or the vertical margin of the map), ignoring the compass needle entirely.Johnson, pp. 134–135 The resulting true bearing or map bearing may then be read at the degree indicator or direction- of-travel (DOT) line, which may be followed as an azimuth (course) to the destination.
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Burt's solar compass axes Burt's solar compass consists of a main plate mounted to the tripod stand and leveled using the two orthogonal attached spirit levels. It carries a common compass needle box, having divisions for the north end of the needle of about 36 degrees, with a vernier to read the needle's variation, and the three adjustable arcs of the solar instrument: one is set for the latitude of the location; another for the seasonal declination of the sun; and the third for the hour of the day adjusted for longitude of the location. The sights to set alignment by the sun are mounted on the movable arm of the declination arc and have a small lens for focusing an image of the sun's disc on the target grating. The upper plate is aligned with the sun and remains stationary after polar alignment, while bearings are taken with the sights on the lower plate.
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In 1855 and 1886, Rundell presented two reports to the Board of Trade and the Houses of Parliament giving his observations on the deviation of the compass in vessels having the compasses corrected by magnets. At the 1851 Great Exhibition, Rundell exhibitied a carbonized cast-iron magnet He proposed a way of marking ships to mark percentages of every ships volume as a guide to determine her freeboard He conducted experiments on the with Frederick J Evans RN. The work with Evans related to dealing with the disturbing elements arising from the iron and the magnetisation of the ships. Evans published his work in conjunction with Archibald Smith In 1889, Rundell created charts showing the horizontal variation in the magnetic force acting on a ship's compass needle by the iron within the ship (Dygograms) for HMS Polyphemus, HMS Curlew and HMS Dreadnought are held at National Maritime Museum, Greenwich He published many articles in The Engineer between 1857 and 1883.
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