Show Testing the Eye Lecturing on the Effect on the Eye of Varying Degrees of Brightness and Contrast before the Illuminating E En En- society recently Dr James I Kerr Herr err of the public health department of the London county council referred to some effects which may be In lug ing Having Hoving to examine e lon long lists list of or figures in black type he tried to fa facIlItate facilitate fa- fa his task by drawing vertical and horizontal lines in red Ink but the different focusing of the black andreal and anel andred red real strained his eye and gave 1 ve him a ahen hen headache which did not trouble him when all the figures and lines lineR were 5 either black or red Do Doctor tor Kerr questions questions ques ques- whether a target Is more distinct n a brilliantly Illuminated disk appears ap ap- pears on a n Jet black background than titan hen n the surroundings were diffusely illuminated |