Bayley, Roger Child, 1869- · London : Iliffe & Sons · leaf 25
ves to two holes ; in fig. 4 we have a central hole with two above and two below it, and it is plain that we could surround the central hole with ring after ring of holes, if we could fit prisms over these holes so that the image formed by each hole fell on the same place on the screen. The prisms… … section of a group of them will approach the curved form, until, if we had an infinite number, we should no longer be able to distinguish the faces of individual prisms, but we should have a group of them which in section we see on the left in fig. 5. But this will be recognised at once as the…
Photography
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.
