The evolution of photography : with a chronological record of discoveries, inventions, etc., contributions to photographic literature, and personal reminiscences extending over forty years (1890)
Werge, John · London : Piper & Carter : John Werge · leaf 254
234 come down, and all that are below must go up. The following diagrams will illustrate this principle still more clearly. Fig. 1. … 0 Point of Observation. Base Line. Fig. 1 is a section of the linear construction of a picture, and will show how the lines converge from the point of observation to the point of sight. Artists, in constructing a landscape of an ordinary form, allot to the sky generally about twice the space…
Photography
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.