CHAPTER X 



HELMHOLTZ IN KfiNIGSBERG STUDIES IN COLOUR 



FROM 1852 to 1856, when he removed to 

 Bonn, Helmholtz was much occupied with 

 the phenomena of colour. Thus, in 1852, there 

 appeared the paper on Sensation already alluded to ; 

 two papers, the first mainly critical, and the second 

 more constructive, on Sir David Brewster's Analysis 

 of Sunlight, and a fundamental paper on the Theory 

 of Colour; and in 1855 we have three papers, all 

 dealing with colour sensation. As often happens, 

 the minds of men of science in different parts of the 

 world may be occupied with the same question about 

 the same period of time. The rifts in the clouds 

 through which shafts of sunlight pass down to the 

 earth may be observed only by the few, but here and 

 there, in the crowd, the eyes of keen observers are 

 attracted by their beauty. Just about this time the 

 phenomena of colour were almost simultaneously 

 before the minds of Sir David Brewster, James Clerk 

 Maxwell, and Helmholtz. Brewster was first in the 

 field, his paper appearing in The Transactions of the 

 Royal Society of Edinburgh in 1822. The first pub- 



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