Spectropia, or, Surprising spectral illusions : showing ghosts everywhere, and of any colour : with sixteen illustrations (1864)
Filmer, John,engraver, James G. Gregory (Firm),publisher · New York : Published by James G. Gregory, no. 540 Broadway · leaf 13
retina. Fourth, those produced by various combinations of the foregoing. It is only the second and third we shall have occasion to touch upon. But before we can well understand their nature, it will be necessary to get a slight knowledge of the structure of the eye, and some idea respecting the… … Fig. 1. order that light falling on it through the pupil (/*) may not be reflected. The pupil is an opening through a diaphragm which is called the iris (i), from its colour varying in different individuals. It has the power of expanding and contracting the pupil, for the purpose of regulating the…
