How to Find the Time at Sea in Less Than a Minute

Gift of William Nesser, 2012.015.046

Calculating a position at sea required special tools, such as a sextant and an accurate timepiece. Booklets such as How to Find the Time at Sea were produced to teach mariners how to determine time when a clock wasn't available. By the time a navigator worked out his position mathematically, the ship had moved, leading to the joke, “A navigator never knows where he is, only where he's been.