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A modern military compass, with included sight device for aligning. A compass is a device that shows the cardinal directions used for navigation and geographic orientation. It commonly consists of a magnetized needle or other element, such as a compass card or compass rose, which can pivot to align itself with magnetic north.
He hung a compass-needle within rings of different materials, pushed the needle aside to about 45°, and counted the number of oscillations made by the needle before the angle of swing decreased to 10°. In a wooden ring the number was 145, in a thin copper ring 66, and in a stout copper ring it was only 33.
A Flinders bar is a vertical soft iron bar placed in a tube on the fore side of a compass binnacle. The Flinders bar is used to counteract the vertical magnetism inherent within a ship and is usually calibrated as part of the process known as swinging the compass , where deviations caused by this inherent magnetism are negated by the use of ...
A sample compass correction card, showing the deviation correction for a given heading. Once the compass has been corrected using small magnets fitted in the base and with soft iron balls, any residual deviation is recorded as a table or graph: the compass correction card, which is kept on board near the compass. [6]
Binnacle with iron correcting spheres at each side and clinometer below compass Modern binnacle with compass A binnacle ( / ˈ b ɪ n ə k əl / ) is a waist-high case or stand on the deck of a ship , generally mounted in front of the helmsman , in which navigational instruments are placed for easy and quick reference as well as to protect the ...
The needle turns to point at a nearby charged object due to charges induced in the ends of the needle by the external charge, through electrostatic induction.For example, if a positively charged object is brought near, the mobile negative charges in the metal will be attracted to it, and move to the end of the needle nearest the object.
Lodestone attracting some iron nails Lodestone in the Hall of Gems of the Smithsonian Lodestone attracting small bits of iron. Lodestones are naturally magnetized pieces of the mineral magnetite. [1] [2] They are naturally occurring magnets, which can attract iron. The property of magnetism was first discovered in antiquity through lodestones. [3]
While compass surveying, the magnetic needle is sometimes disturbed from its normal position under the influence of external attractive forces. Such a disturbing influence is called as local attraction. [1] The external forces are produced by sources of local attraction which may be current carrying wire (magnetic materials) or metal objects. [2]