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 26
allel rays, or principal focus. A real pencil is composed of innumerable rays, and such pencils from innumerable points in the object meet and cross at the lens on their way to cor¬ responding points in the image, and wonderful to tell, no one is switched from the track for another, and there are… … in order to meet the axial rays at fv and so it is seen that the margin of the lens G D has a greater refracting angle than the more central portions. But the trouble is, the refracting at the margin is overdone, so that the rays d d meet the axial ray at/3 instead of at/r Hence if a ground-glass…
Lantern projection · Slides (Photography)
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.
![An illustration from Essai de physique, par Mr. Pierre van Musschenbroek ... avec une description de nouvelles sortes de machines pneumatiques, et un recueil d'expériences par Mr. J. v[an] M[usschenbroek] Traduit du hollandois par Mr. Pierre Massuet .. (1751)](https://img.insideoutlibrary.com/img/200/ia-essaidephysiquep02muss-131-37.webp)
