hea Per Second
424
FLICKER WITH MOVING PICTURES
[Ch. XT
1 00 I 2 3 4
Logarithm of Illumination
Fi<;. 234. Thk Relation Between the Illumination of the Screen
and the Number of Flashes per Second at which Flicker just
Disappears.
If the flashes are more frequent than indicated by the curve for a given
illumination there will lie no flicker, hut if less frequent, flicker will be seen.
The solid line represents the observation of T. C. Porter and the dotted line
represents some rough observations made by the authors.