ON Goethe's scientific eeseaeches. 41 



sufficiently proved his rules. He next attempted to ex- 

 plain his supposed discovery to a neighbour, who was a 

 physicist, and was disagreeably surprised to be assured by 

 him that the experiments were well known, and fully 

 accounted for in Newton's theory. Every other natural 

 philosopher whom he consulted told him exactly the same, 

 including even the brilliant Lichtenberg, whom he tried 

 for a long time to convert, but in vain. He studied 

 Newton's writing's, and fancied he had found some falla- 

 cies in them which accounted for the error. Unable to 

 convince any of his acquaintances, he at last resolved to 

 appear before the bar of public opinion, and in 1791 and 

 1792 published the first and second paits of his 'Contri- 

 butions to Physical Optics,' 



In that work he describes the appearances presented by 

 white discs on a black ground, black discs on a white 

 gTound, and coloured discs on a black or white ground, 

 when examined through a prism. As to the results of 

 the experiments there is no dispute whatever between him 

 and the physicists. He describes the phenomena he saw 

 with great truth to nature ; the style is lively, and the 

 arrangement such as to make a conspectus of them easy 

 and inviting ; in short, in this as in all other cases where 

 facts are to be described, he proves himself a master. At 

 the same time he expresses his conviction that the facts 

 he has adduced are calculated to refute Newton's theory. 

 There are two points especially which he considers fatal to 

 it : first, that the centre of a broad white surface remains 

 white when seen through a prism ; and secondly, that 

 even a black streak on a white gTOund can be entirely 

 decomposed into colours. 



Newton's theory is based on the hypothesis that there 

 exists light of different kinds, distinguished from one 

 another by the sensation of colour which they produce in 

 the eye. Thus there is red, orange, yellow, gi-een, blue, 



