A Compass Course
As with many products that we take for granted today, the magnetic compass was once a revolutionary technology. Early mariners knew how to navigate their vessels using a knowledge of basic astronomy, but in overcast conditions they had no way of knowing how to steer a course until the invention of the compass.
The first recorded use of a magnetic compass comes from the Chinese writer Zhu Yu in the early 12th century: “The ship’s pilots are acquainted with the
