The sciopticon manual : explaining Marcy's new magic lantern, and light, including magic lantern optics, experiments, photographing and coloring slides, etc. (1874)
Marcy, L. J., author · Philadelphia : L.J. Marcy · leaf 21
11 SCIOPTICON MANUAL. SIZE OX THE RETINA. A A (Fig. 2) represents the visible portion of the sclerotica of the human eye, which is a camera obscura … distant objects upon it must be Fig. 2. 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 T^th part of an inch. The face of such an image is included in a circle whose diameter is about y2th of…
Lantern projection · Slides (Photography)
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.
