IRRADIATION 697 



colored objects, it has been observed that the border of irradiation takes 

 a color complementary to that of the object itself. This is particularly 

 well marked when the objects are steadily looked at for some time. 

 Illustrations of this point also are very simple. In looking steadily at 

 a red spot or figure on a white ground, a faint areola of a pale green 

 soon appears surrounding the red object; or if the image is yellow, the 

 areola will appear pale blue. These appearances are called accidental 

 areolae. 



