The Sciopticon manual : explaining lantern projections in general, and the Sciopticon apparatus in particular, including magic lantern attachments, experiments, novelties, colored and photo-transparencies, mechanical movements, etc. (1877)
Marcy, L. J. (Lorenzo J.) · Philadelphia : J.A. Moore · leaf 20
11 SCIOPTICON MANUAL. SIZE ON THE RETINA. A A (Fig. 2) represents the visible portion of tho sclerotica of the human eye, which is a camera obscura … distant objects upon it must be Tig. 9. very minute. For example, the figure of a man 6 feet high, seen at a distance of 40 feet, produces an image upon the retina the height of which is about TVth part of an inch. The face of such an image is included in a circle whose diameter is about yVjth of…
Lantern projection · Slides (Photography)
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.
