April 27, 2026

Antique Highlight: Napoleon III Marine Hourglass

This week at French Metro we are taking a look at this nineteenth century Napoleon III period hourglass. This hourglass was originally used aboard a ship at sea and features bronze supports and ebonized wooden rings to protect the sandglass within.

The marine hourglass was an effective tool at sea and still in use by the 1860s when this glass is from, despite the invention of marine clocks and the like. The marine glass was used in a number of ways by sailors to find longitude, calculate the speed of a ship in knots, and to set watches. Hourglasses were used on ships to help determine longitude by providing the time for the ship's log. To find longitude, a ship's captain needed to know the time on the ship and the local time of a place with a known longitude.

Regarding the speed of the ship, the hourglass was used in conjunction with a rope with many knots tied into it with a weight on one end. The hourglass would be turned over and the weight dropped into the sea. The number of knots that slipped through a sailors hands in the timeframe set by the hourglass would determine the speed. A knot is roughly 1.15 miles per hour on the ocean. The fastest sailing ships in the 19th century could reach speeds of up to 20 knots, or 23 miles per hour.

This hourglass has a time of twelve minutes and when flipped five times would add up to be an hour. With its classic Napoleon III black and gold color scheme, this large scale piece is sure to make a statement.