This document discusses the lost art of celestial navigation using the stars. It explains how sailors could determine their latitude using Polaris, the North Star. The document also describes how sailors could determine their longitude by tracking the position of stars near the eastern or western horizon over multiple nights. Finally, it mentions an instrument called a Mariner's Nocturnal that could be used to determine the time by measuring the angle between Polaris and stars in Ursa Major or Ursa Minor.