The compass is a tool used by land and sea explorers to help them navigate their journeys. Before compasses were developed, people used the sun, wind, and stars as their guides, but the compass allowed them to calculate their location and direction with greater accuracy.

During the first century B.C., the Chinese observed that pieces of lodestone, an iron mineral, always pointed north when they were placed on a surface; this discovery led to the development of the compass. The first Chinese compass was a spoon made of lodestone that rested on a smooth surface with markings indicating the four directions. The next step in the advancement of compasses was to enclose the lodestone in a decorative casing with a projecting needle to indicate which direction was north. One problem compass makers encountered was that the iron they used for the pointer lost its magnetism easily. After...