"Sextant. An important instrument of navigation and surveying, for measuring the angular distance of two stars or other objects, or the altitude of a star above the horizon..." a, handle; b, c, mirrors; d, ring; e, telescope; f, arm; g, reading-lens; h, arc; i, screw; j, tangent screw. -Whitney, 1911

Sextant

"Sextant. An important instrument of navigation and surveying, for measuring the angular distance of…