Browning. — On After-images. 509 



and yellow tints changed places quickly ; finally a yellow spot 

 was left in a yellow background ; and, when I had apparently 

 lost sight of the image, I opened my eyes and found it again 

 on the page of the book I had been reading. 



It was curious and interesting to note how the colours 

 would change places for a moment — an orange sun would 

 appear on a yellow background, and suddenly give place to a 

 yellow sun on an orange background. These changes lasting 

 only for a moment, made the taking of accurate notes almost 

 impossible. 



(3.) I looked at the bright streak of light of a kerosene- 

 stove, shut my eyes, but allowed the light to fall on the lids. 

 First a yellow streak with a green halo appeared on a purple 

 background ; the halo disappeared, leaving yellow on purple ; 

 then a blue streak on a purple background, the blue gradually 

 darkening till it appeared black, on a purple-grey back- 

 ground. This gave a negative image. 



(4.) On trjdug the same experiment; but covering my eye- 

 lids, I found the image did not last as long. The yellow 

 streak turned to orange, then to green with yellow halo, 

 changing into dark-green, and then into a dark streak, the 

 background being purple, varying in shade. 



(5.) One evening I was walking up the Coote Eoad, when 

 the presence of a persistent after-image showed me that I 

 must have been looking unconsciously at a bright light. On 

 recalling the circumstances I came to the conclusion that the 

 light might have been that of a candle iu the room I had just 

 left, or that of the lamp at the corner opposite Eussell's store. 

 I walked quickly up Shakespeare Eoad and Clyde Eoad, but 

 the image would not leave me until I reached the turning to 

 Brewster Lane. 



Examples and illustrations might be continued indefinitely, 

 but I think I have said enough to prove that positive images 

 change into negative, and it would be interesting if it could 

 be shown that the changes of colour followed a fixed rule, as 

 I am inclined to think. But, as I said before, experiments 

 are trying to the eyes, and I found I could not continue my 

 observations for long at one time. 



I have been unable to obtain access to the latest researches 

 on this subject, which is an interesting one, as it forms an 

 introduction to the great subject of mental reproduction. 



