Who first used the properties of a magnet to show direction,and why?

(N/A) thin long piece of a magnet,when suspended freely,points in the north-south direction.
When it is placed on a piece of cork and allowed to float in still water,it also shows the north-south direction.
The name 'lodestone' (or 'loadstone') given to a naturally occurring ore of iron,magnetite,means 'leading stone'.
The first use of magnets was made by the Chinese people to determine direction while traveling at sea.
Caravans crossing the Gobi desert also employed magnetic needles.
$A$ Chinese legend narrates the tale of the victory of the emperor Huang-ti about four thousand years ago,which he owed to his craftsmen (engineers).
These engineers built a chariot on which they placed a magnetic figure with arms outstretched. The figure swiveled around so that the finger of the statuette on it always pointed south. With this chariot,Huang-ti's troops were able to attack the enemy from the rear in thick fog and to defeat them.