Vision in the Ultra-Violet

Abstract

IN a letter in NATURE of November 10 (p. 736) Prof. Fabry mentions two publications by Saidman on this subject, hitherto unknown to me, which I read with great interest. In one of them the correlation of the property of seeing ultra-violet light with age is discussed. As I measured quantitatively V₃₆₅₀/V₄₀₄₇ and V₃₁₃₀/V₄₀₄₇ it seemed to me of some interest to publish a graph (Fig. 1) of these quantities against age, which confirms well that there is a general decrease of visibility between thirty and forty-five years of age, as affirmed by Saidman. Indeed, also in my case no one older than forty-three could perceive light of wave-length 3130.