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 82
n of a line, its distance from the eye contributes towards determining the size of the visual angle, and conse- quently modifies the apparent length of the line. This wire being held upright, and at a certain distance from the supposed eye, forms a visual angle of a certain size; if I remove the… … Or, keeping the wire fixed in a vertical position, if I cause the threads to meet at a point close to the line, which point of meeting is supposed to repre- sent the position of the eye, the visual angle is evidently larger than if I cause the threads to meet at a point removed to a greater…
Drawing · Perspective
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.
