Saturday, September 22, 2007
The Story:
A compass (or mariner's compass) is a navigational instrument for finding directions on the Earth. It consists of a magnetized pointer free to align itself accurately with Earth's magnetic field, which is of great assistance in navigation. The face of the compass generally highlights the cardinal points of North, South, East and West. A compass can be used in conjunction with a marine chronometer to calculate longitude) and a sextant to calculate latitude, providing a very accurate navigation capability. This device greatly improved maritime trade by making travel safer and more efficient. An early form of the compass was invented in China in the 11th century. The familiar mariner's compass was invented in Europe around 1300, from whence later originated the liquid compass and the gyrocompass.
More technically, a compass is a 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 or astrocompass, which does not depend on the earth's magnetic field for its operation, can also be used to find true north.
Source:http://en.wikipedia.org/wiki/Compass
too beautiful ;
9:30 PM;
9:30 PM;