ON Goethe's scientific reseakches. 43 



coloui'ed throughout, it has on one side a margin of blue 

 and violet, on the other a margin of red and yellow. A 

 black patch between two bright surfaces may be entirely 

 covered by their coloured edges ; and when these spectra 

 meet in the middle, the red of the one and the violet of 

 the other combine to form purple. Thus the colours into 

 which, at first sight, it seems as if the black were analysed 

 are in reality due, not to the black strip, but to the white 

 on each side of it. 



It is evident that at the lirst moment Goethe did not 

 recollect Newton's theory well enough to be able to find 

 out the physical explanation of the facts I have just 

 glanced at. It was afterwards laid before him again and 

 again, and that in a thoroughly intelligible form, for he 

 speaks about it several times in terms that show he under- 

 stood it quite correctly. But he is still so dissatisfied with 

 it, that he persists in his assertion that the facts just cited 

 are of a nature to convince any one who observes them of 

 the absolute incorrectness of Newton's theory. Neither 

 here nor in his later controversial writings does he ever 

 clearly state in what he conceives the insufficiency of the 

 explanation to consist. He merely repeats again and again 

 that it is quite absurd. And yet I cannot see how any one, 

 whatever his views about colour, can deny that the theory 

 is perfectly consistent with itself; and that if the hypo- 

 thesis from which it starts be granted, it explains the 

 observed facts completely and even simply. Newton him- 

 self mentions these spurious spectra in several passages of 

 his optical works, without going into any special eluci- 

 dation of the point, considering, of course, that the 

 explanation follows at once from his hypothesis. And he 

 seems to have had good reason to think so ; for Groethe no 

 sooner began to call the attention of his scientific friends 

 to the phenomena, than all with one accord, as he himself 

 tells us, met his difficulties with this explanation from 

 Newton's principles, which, though not actually in his 



