Somewhere between 12th and 13th century, compass arrived in Europe in both dry and floating forms. It prolonged sailing season, which was earlier between October and April and relied on the clear skies, to the whole year which in turn resulted in a gradual, but sustained increase in shipping movement.
Compass appeared in Islam world in 13th century. Except for naval navigation it was also used for astronomical purposes, same as in Europe. It was also used as Qibla Kabba indicator to find the direction to Mecca for daily prayers. Improved version of this indicator was invented by Syrian astronomer and timekeeper Ibn al-Shatir in 14th century. It was a combination of universal sundial and a magnetic compass.
In time, different variants of compass were invented. Dry mariner's compass was invented in Europe in 14th century and was standard compass placed in three-ring gimbals which held compass in horizontal position. In any case, the arrival of the compass was very significant for seafaring navigation, which, until that point, had relied on the sun or stars.
The arrival of the compass allowed for maritime travel throughout the year, as opposed to being restricted to the fairer months. With a compass in hand, European mariners were better equipped to sail in the open seas, out of sight of land. The compass was a major contributor to the possibility of the Age of Discovery: a time of worldwide exploration on the part of Europeans that occurred roughly between the 15th and 18th centuries.
It was during this time that navigators and merchants charted sea routes to China, Japan and the Indonesian Islands, and established the trade of silk, tea and spices. It was also the time when Spanish conquistadors were encountering the Aztec and Inca civilizations of Central and South America and when explorers were learning of the wondrous natural resources of North America.
The increase in sea travel and trade routes, enabled by the compass, led to European settlements in the Americas. By the 16th century, compasses and charts were indispensable tools for ships sailing at sea. But even then, navigators and sailors knew that there was something strange about their compasses. During the 15th Century, navigators began to understand that compass needles do not point directly to the North Pole but rather to some nearby point; in Europe, compass needles pointed slightly east of true north.
In the s, British scientists initiated what became known as the Magnetic Crusade. This was an opportunity for Victorian scientists to travel around the world to measure magnetic deviation. Over the centuries a number of technical improvements have been made in the magnetic compass.
Many of these were pioneered by the British, whose large empire was kept together by naval power and who relied heavily upon navigational devices. By the 13th century, the compass needle had been mounted upon a pin standing on the bottom of the compass bowl.
At first only north and south were marked on the bowl, but then the other 30 principal points of direction that are familiar to us today were filled in. The 32 cardinal points were originally drawn to indicate winds, and were used by sailors in navigation.
The 32 points represented the eight major winds, the eight half-winds, and the 16 quarter-winds. All 32 points, their degrees, and their names can be seen here.
On early compass roses, the eight major winds can be seen with a letter initial above the line marking its name, as we do with N north , E east , S south , and W west today. Later compass roses, around the time of Portuguese exploration and Christopher Columbus, show a fleur-de-lys replacing the initial letter T for tramontana, the name of the north wind that marked north, and a cross replacing the initial letter L for levante that marked east, showing the direction of the Holy Land.
Flavio Gioja fl. Magnetic compasses are the most well known type of compass. While the design and construction of this type of compass has changed significant ly over the centuries, the concept of how it works has remained the same. Magnetic compasses consist of a magnetized needle that is allowed to rotate so it lines up with the Earth's magnetic field.
The ends point to what are known as magnetic north and magnetic south. Ancient Greeks understood magnetism. As early as 2, years ago, Chinese scientists may have known that rubbing an iron bar such as a needle with a naturally occurring magnet , called a lodestone , would temporarily magnetize the needle so that it would point north and south.
Very early compasses were made of a magnetized needle attached to a piece of wood or cork that floated freely in a dish of water. As the needle would settle, the marked end would point toward magnetic north.
As engineer s and scientists learned more about magnetism, the compass needle was mounted and placed in the middle of a card that showed the cardinal direction s—north, south, east, and west. A spearhead and the letter T, which stood for the Latin name of the North Wind, Tramontana , signified north. This combination evolve d into a fleur-de-lis design, which can still be seen today. All 32 points of direction were eventually added to the compass card. Historians think China may have been the first civilization to develop a magnetic compass that could be used for navigation.
Chinese scientists may have developed navigational compasses as early as the 11th or 12th century. Western Europeans soon followed at the end of the 12th century. In their earliest use, compasses were likely used as backups for when the sun, stars, or other landmark s could not be seen. Eventually, as compasses became more reliable and more explorers understood how to read them, the devices became a critical navigational tool.
This discrepancy between magnetic north and true north is called variation by mariner s or pilot s or magnetic declination by land navigators and varies depending on location. Variation is not significant when using magnetic compasses near the Equator , but closer to the North and South Poles, the difference is much greater and can lead someone many kilometers off-course.
Navigators must adjust their compass readings to account for variation. Other adaptation s have been made to magnetic compasses over time, especially for their use in marine navigation. When ships evolved from being made of wood to being made of iron and steel , the magnetism of the ship affected compass readings.
This difference is called deviation. Adjustments such as placing soft iron balls called Kelvin sphere s and bar magnets called Flinders bar s near the compass helped increase the accuracy of the readings.
Deviation must also be taken into account on aircraft using compasses, due to the metal in the construction of an airplane. Magnetic compasses come in many forms. The most basic are portable compasses for use on casual hikes. Magnetic compasses can have additional features, such as magnifiers for use with maps, a prism or a mirror that allows you to see the landscape as you follow the compass reading, or markings in Braille for the visually impaired. The most complicated compasses are complex devices on ships or planes that can calculate and adjust for motion, variation, and deviation.
Since magnetic north is not measured, variation is not an issue. Once the gyroscope begins spinning, motion will not disturb it. This type of compass is often used on ships and aircraft. A solar compass uses the sun as a navigational tool. The most common method is to use a compass card and the angle of the shadow of the sun to indicate direction.
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