STEP 1: Using a pencil and ruler, draw a horizontal line. Set the compass to the width of the line. Place the compass at either end of the line and draw two arcs that cross in the middle.

Earliest records show a spoon shaped compass made of lodestone or magnetite ore, referred to as a "South-pointer" dating back to sometime during the Han Dynasty (2nd century BCE to 2nd century CE).

When you measure in the horizontal axis such as on a flat shelf, the screen shows two circles instead. This article explains how to use the iPhone compass and level. Instructions apply to iPhones ...