Antique 18th c. Sea Captain / Shipmasters Ivory rule



Rare 18th c. Shipmaster 4 fold ivory ruler. In the day the sea captain / shipmaster was accountable for the safety and contents on the ship, its safety cargo and personal. This rule opens to 24″ and contains every possible table known to man in the day.

Tables include:
–  The specific weight of a trees lumber dry
–  Specific weight of every metal
–  Organic usable material of the day
–  The size of musket balls and barrel diameters
–   Engineering table

The rule appointments are German silver and lock the rule into a 90 degree position as well. The most intriguing and rarest rule I’ve owned it 50 years. Contact me for price.