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 131
110 PRACTICE WITH THE appear about one-fourth less, — in other words, the distant line would appear about three-fourths of the near line. If placed one-twentieth part only of the distance further off, it would appear only one-twentieth part shorter nearly, and so on. … The relation of the visual angles is thus found by a simple arithmetical operation with all the necessary accuracy for practice; and, indeed, were the common way adopted of determining the relations of these lengths, (see Chapter XV. on Geometrical Perspective,) by means of vanishing lines, this…
Drawing · Perspective
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.
