Search results
Results from the WOW.Com Content Network
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.
But there was limited use of native (unsmelted) iron ore, from magnetite, iron pyrite and ilmenite (iron–titanium), especially in the Andes (Chavin and Moche cultures) and Mesoamerica, after 900 BC and until c. 500 CE. Various forms of iron ore were mined, [30] drilled and highly polished.
In 1399, an Egyptian reports two different kinds of magnetic compass. One instrument is a “fish” made of willow wood or pumpkin, into which a magnetic needle is inserted and sealed with tar or wax to prevent the penetration of water. The other instrument is a dry compass. [65] Navigational sailor's compass rose, 1607
It overcame the vagaries of the surveyor's compass caused by interference from iron ore deposits in a local land mass district. [5] Burt first used the solar instrument in his Michigan surveys. [6] He found large outcropping deposits of iron ore at Negaunee in Marquette County in his later 1844 survey of the upper peninsula of the state of ...
The carbon monoxide produced by the charcoal reduced the iron oxide from the ore to metallic iron. The bloomery, however, was not hot enough to melt the iron, so the metal collected in the bottom of the furnace as a spongy mass, or bloom. Workers then repeatedly beat and folded it to force out the molten slag.
The sources of local attraction may be natural or artificial. Natural sources include iron ores or magnetic rocks while as artificial sources consist of steel structures, iron pipes, current carrying conductors. The iron made surveying instruments such as metric chains, ranging rods and arrows should also be kept at a safe distance apart from ...
The eyed needle — a sewing tool made of bones, antlers or ivory that first appeared around 40,000 years ago in southern Siberia — might be hiding important clues about the beginnings of ...
He created a compass in which the needle was floated in a goblet of water, attached to a cork to make it neutrally buoyant. The needle could orient itself in any direction, so it dipped to align itself with the Earth's field. Norman also created a dip circle, a compass needle pivoted about a horizontal axis, to measure the effect. [4] [8]