By the 3rd century C.E., Chinese scientists had studied and learned much about magnetism in nature. Alchemists learned to "make magnets" by heating pieces of ore to red hot temperatures and then cooling the pieces in a North/South position. The magnet was then placed on a piece of reed and floated in a bowl of water marked with directional bearings. These first navigational compasses were widely used on Chinese ships by the 11th century. Knowledge of the compass as a directional device came to Western Europe sometime in the 1100's, and (oddly) to the Arabic people soon after. With the use of the compass, navigation was dramatically improved; now navigators could know where their ships were headed on the cloudiest of days -- or even at night!