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A compass (or mariner's compass) is navigational instrument for finding directions. It consists of a magnetised pointer free to align itself accurately with Earth's magnetic field. A compass provides a known reference direction which is of great assistance in navigation. The cardinal points are north, south, east and west. A compass can be used in conjunction with a clock and a sextant to provide a very accurate navigation capability. This device greatly improved maritime trade by making travel safer and more efficient.
Navigational mariner's compass
A compass can be any magnetic device using a needle to indicate the direction of the magnetic north of a planet's magnetosphere. Any instrument with a magnetized bar or needle turning freely upon a pivot and pointing in a northerly and southerly direction can be considered a compass. A compass dial is a small pocket compass with a sundial. A variation compass is a specific instrument of a delicate type of construction. It is used by observing variations of the needle. A gyrocompass can also be used to ascertain true North.
Compasses were initially used in mysticism in ancientFor the span of recorded history starting roughly 5,000-5,500 years ago, see Ancient history''. Ancient is a Norwegian band that, while not really troll metal, had troll metal themes on their 1994 EP 'Trolltaar'. The band started as a solo project of guit ChinaThis article is on the geographic and cultural entity. For other meanings, see China (disambiguation). China ( Traditional Chinese: , Simplified Chinese: , Hanyu Pinyin: Zhongguo, Wade-Giles: Chung-kuo) is a country in continental East Asia with some oute. The first known use of Earth's magnetic field in this way occurred in ancient China as a spectacle. Arrows were cast similarly to dice. These magnetised arrows aligned themselves pointing north, impressing the audience. Curiously, it took some time for this trick to get used by the Chinese for naval navigation, but by the 11th or early 12th century it had become common.
Knowledge of the compass moved overland to Europe sometime later in the 12th century. Arab mariners apparently learned of it from the Europeans, adopting its use in the first half of the 13th century. About 1358, there is a story about an English monk under the name Nicholas of LynneNicholas of Lynne Minorite a "priest with an astrolabe" from Oxford who is thought to have visited the northern lands around Greenland around 1360, returning to Bergen in 1364 in the company of 8 others. It is conjectured that he may also have visited Hud, who served as a navigator due to his competence and knowledge in the "magnetic compass". (See Inventio Fortunata .)
Prior to the introduction of the compass, wayfinding at sea was primarily done via celestial navigationCelestial navigation is a position fixing technique that was the first system devised to help sailors locate themselves on a featureless ocean. Celestial navigation uses angular measurements (sights) between the horizon and a common celestial object., supplemented in some places by the use of soundings. Difficulties arose where the sea is too deep for soundings and conditions are continually overcast or foggy. Thus the compass was not of the same utility everywhere. For example, the Arabs could generally rely on clear skies in navigating the Persian GulfThe Persian Gulf ( Persian: , Arabic: ) is an extension of the Gulf of Oman in between the Arabian Peninsula and Iran. This inland sea of some 233,000 kmē is connected to the Gulf of Oman in the east by the Strait of Hormuz, and its western end is marked and the Indian OceanThe Indian Ocean is the third-largest body of water in the world, covering about 20% of the Earth's water surface. It is bounded on the north by southern Asia (the Indian Sub-continent); on the west by the Arabian Peninsula and Africa; on the east by the (as well as the predictable nature of the monsoonA monsoon is a periodic wind, especially in the Indian Ocean and southern Asia. The word is also used to label the season in which this wind blows southwest in India and adjacent areas that is characterized by very heavy rainfall, and specifically the rais). This may explain in part their relatively late adoption of the compass. Mariners in the relatively shallow Baltic made extensive use of soundings.
In the Mediterranean, however, the practice from ancient times had been to curtail sea travel between October and April, due in part to the lack of dependable clear skies during the Mediterranean winter (and much the sea is too deep for soundings). With improvements in dead reckoning methods, and the development of better charts, this changed during the second half the 13th century. By around 1290 the sailing season could start in late January or February, and end in December. The additional few months were of considerable economic importance; it enabled Venetian convoys, for instance, to make two round trips a year to the eastern Mediterranean, instead of one.
Around the same time traffic between the Mediterranean and northern Europe increased, and one factor may be that the compass made traversal of the Bay of Biscay safer and easier.
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