Abstract :
Dr. P. W. Cobb, of the Nela Research Laboratory, has just made public a preliminary report upon some experiments which he undertook for the purpose of obtaining a fundamental idea of the influence of levels of illumination upon the speed of vision, and ultimately, if possible, of determining the exact relation existing between these two things. While these experiments make certain assumptions which have not yet been experimentally tested and technical application of the results are therefore not warranted at the present time, Dr. Cobb´s investigations clearly show that there is a general relation between speed of vision and illumination intensities, and indicate that this relation is different for different individuals. The following is an abstract of Dr. Cobb´s report on these experiments.