This Vintage Brass Marine 3 Minute Navigare Necesse Est Sandglass is a unique and historically significant maritime navigational instrument. Originating from France, this antique original piece is made of brass and features the phrase "Navigare Necesse Est," meaning "Navigation is Necessary." Measuring a 3-minute navigational course in repeated measures of small time, this sandglass was used to determine boat speed and is a testament to the rich maritime history and navigation techniques of the past.