Details
A rare 18th-Century fortification rule,
unsigned, engraved on the upper surface with corresponding scales, tabulated for Angle du Centre and Angle Poligon; an arc engraved 1-50; lines radiating from a point with hinged rule measuring 0-90, and engraved for Capitale, Transuersale Gorge Flanc, Flanc au square (symbol), the underside with scale rule and scales for Pied Geometric, Pied Bruxelles, Pied de Hollande, the scales shown with fractions, the rule -- 6in. (16.5cm.) wide
See Colour Illustration
unsigned, engraved on the upper surface with corresponding scales, tabulated for Angle du Centre and Angle Poligon; an arc engraved 1-50; lines radiating from a point with hinged rule measuring 0-90, and engraved for Capitale, Transuersale Gorge Flanc, Flanc au square (symbol), the underside with scale rule and scales for Pied Geometric, Pied Bruxelles, Pied de Hollande, the scales shown with fractions, the rule -- 6in. (16.5cm.) wide
See Colour Illustration