Dutch slide rule
1960-1970
Dutch slide rules
1960-1970
Slide rule
1960-1970
Hills slide rule, ivory, for artillery use
Artillery slide rule
Wooden slide rule for artillery rangefinding
1816-1827
Dutch slide rule
1960-1970
Dutch slide rule
1960-1970
Dutch slide rule
1960-1970
Dutch slide rule
1960-1970
Altitude slide rule for ballistics use by Dring & Fage
1916
