Cited by C.S. Sherrington, 'On Reciprocal Action in the Retina as studied by means of some Rotating Discs', Journal of Physiology 21 (1) (1897), pp. 33-54.
Description:

'Rood [note: 'American Journ. of Science, XLVI. p. 173. 1893.'] has recently re-introduced to notice a method of photometry advocated on not very convincing grounds by Schafhäutl [note: Universal Vibrations-photometer: Akad. d. Wiss. München, VII. p. 465.] forty years ago. The method is based on Plateau's [note: 'Dissert. sur quelques propriétés des impressions &c. Liège, 1829.] research, and proceeds on the well-known relation existing in light-sensations between their intensity and the rate of frequency of repetition required to fuse them.' (34)

Plateau [note: 'loc. cit.'] had noted that strong light-sensations suffer perceptible decrease [of speed of development in vision] more quickly than do weak - that is, had found his "duration of apparent constancy" more brief for the former' (35)