Contributions to the History of Psychology: LXXXIII. J. E. Purkinje and Mathias Klotz: Who First Described “The Phenomenon”?

In 1825 Purkinje described the effects of increasing ambient illumination at early dawn, beginning with darkness, on the perception of spectral colors. The blues were seen first When reds became visible, they appeared less bright than the blues. The usually dependable Brockhaus Encyclopedia stated (1972) that the phenomenon was described in 1816 by Mathias Klotz and rediscovered (“erneut entdeckt”) by Purkinje. As it turns out, Klotz correctly described the effects of low ambient illumination on the relative brightness but his report on visibility contradicts Purkinje's observations, amply confirmed by subsequent investigators and known, in fact, prior to Purkinje's report.