A manual for teaching model-drawing : from solid forms, the models founded on those of M. Dupuis : combined with a popular view of perspective, and adapted to the elementary instruction of classes in schools and public institutions (1843)
Williams, J. Butler, Sir, Lowry, Joseph Wilson, 1803-1879 · London : J. W. Parker · leaf 192
171 WIRE MODELS. Three equal Arcs of a Circle, vertically equidistant from one another. Above the eye. … Left. Middle. Right. Two equal Arcs (Convex) bounded by a straight line. Above the eye. Left. Middle. Right. The same as above, without the straight line, and therefore less definite, and a little more difficult to draw. Middle. Right. Lelt.
Drawing · Perspective
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.