Chromatic Aberration of the Eye

Abstract

THERE is a slight inaccuracy in your report of my communication of May 12th to the Physical Society, wherein I am made to affirm that a blue object and a red object cannot both be in focus at once unless the blue object be the more distant. The next sentence of your report, and indeed the whole tenor of my communication imply the reverse condition that the blue rays should come from the less distant source. The dispersion of the eye takes place in the same sense as its refraction; hence the adjustment of the eye to focus may be the same for blue rays proceeding from a body near the eye as for red rays proceeding from an indefinitely distant luminous source; as, indeed, Fraunhofer proved half a century ago.