Plane and spherical trigonometry
A textbook of plane and spherical trigonometry by George Albert Wentworth, published by Ginn & Company in Boston in 1887 for American secondary and college students, with sections on surveying and navigation. The 85 line figures pair solid and dashed strokes: labeled triangles, arcs, celestial spheres crossed by great circles, and survey diagrams usable as spare geometric motifs or diagram scaffolds.
