The sextant superseded all of its navigational predecessors due to its accuracy, and is sometimes still used to this day as a backup. With the introduction of the sextant, sailors could not only find their latitude but, they could also calculate longitude with the help of a marine chronometer.

Sailors typically used 30-minute or one-hour sand glasses to track watch duties and measure the passage of time. Combined with a chip log the sand glass allowed mariners to calculate how far they had travelled in a set time, a remarkably effective method in an era without precise timekeeping.

It usually consisted of a polished brass frame with a wooden handle, used to measure angles greater than 180 degrees. At sea it was used for finding longitude. Invented by the German astronomer Tobias Mayer in 1752, its use was more widespread in the French than in the British navy.

➡️ Read more about Elizabeth I of England here: