262 THE HISTORY OF SCIENCE 



graphic vividness. The history of literature and art 

 furnishes us with illustrations of remarkable powers 

 of visualization. Blake and Fromentin were able to 

 reproduce in pictures scenes long retained in memory. 

 The latter recognized that his painting was not an 

 exact reproduction of what he had seen, but that it 

 was none the less artistic because of the selective influ- 

 ence that his mind had exerted on the memory image. 

 Wordsworth at times postponed the description of a 

 scene that appealed to his poetic fancy with the ex- 

 press purpose of blurring the outlines, but enhancing 

 the personal factor. Goethe had the power to call up 

 at will the form of a flower, to make it change from 

 one color to another and to unfold before his mind's 

 eye. Professor Dilthey has collected many other 

 records of the hallucinatory clearness of the visual 

 imagery of literary artists. 



On the other hand, Galton, after his classical 

 study of mental imagery (1883), stated that scientific 

 men, as a class, have feeble powers of visual repre- 

 sentation. He had appealed for evidence of visual 

 recall to distinguished scientists because he thought 

 them more capable than others of accurately stating 

 the results of their introspection. He had recourse 

 not only to English but to foreign scientists, includ- 

 ing members of the French Institute. " To my aston- 

 ishment," he writes, " I found that the great majority 

 of men of science to whom I first applied protested 

 that mental imagery was unknown to them, and they 

 looked on me as fanciful and fantastic in supposing 

 that the words 4 mental imagery ' really expressed 

 what I believed everybody supposed them to mean. 

 They had no more notion of its true nature than a 



