1880.] on Goethe 8 ' Farhenlehre: 345 



liquid, the blue colour disappeared, and he had yellow iu its place. 

 Such experiments are capable of endless variation. To this class 

 of eifects belongs the painter's " chill." A cold bluish bloom, 

 like that of a plum, is sometimes observed to cover the browns of 

 a varnished picture. This is due to a want of optical continuity 

 in the varnish. Instead of being a coherent layer it is broken up 

 into i^articles of microscopic smalluess, which virtually constitute a 

 tiu'bid medium and send blue light to the eye. 



Goethe himself describes a most amusing illustration, or, to use 

 his own language, " a wonderful phenomenon," due to the temporary 

 action of a turbid medium on a picture. " A portrait of an esteemed 

 theologian was painted several years ago by an artist specially skilled 

 in the treatment of colours. The man stood forth in his dignity clad 

 in a beautiful black velvet coat, which attracted the eyes and awakened 

 the admiration of the beholder almost more than the face itself. 

 Through the action of humidity and dust, however, the picture had 

 lost much of its original splendour. It was therefore handed over to a 

 painter to be cleaned, and newly varnished. The painter began by 

 carefully passing a wet sponge over the picture. But he had scarcely 

 thus removed the coarser dirt, when to his astonishment the black 

 velvet suddenly changed into a light blue j)lush; the reverend gentle- 

 man acquiring thereby a very worldly, if, at the same time, an old- 

 fashioned appearance. The painter would not trust himself to wash 

 further. He could by no means see how a bright blue could underlie 

 a dark black, still less that he could have so rapidly washed away a 

 coating capable of converting a blue like that before him into the 

 black of the original painting." 



Goethe inspected the picture, saw the phenomenon, and explained 

 it. To deepen the hue of the velvet coat the painter had covered it 

 with a sjiecial varnish, which, by absorbing part of the water passed 

 over it, was converted into a turbid medium, through which the black 

 behind instantly appeared as blue. To the great joy of the painter, 

 he found that a few hours continuance in a dry 2)lace restored the 

 primitive black. By the evaporation of the moisture the optical 

 continuity of the varnish (to which essential point Goethe does not 

 refer) was re-established, after which it ceased to act as a turbid 

 medium. 



This question of turbid media took entire possession of the poet's 

 mind. It was ever present to his observation. It was illustrated by 

 the azure of noonday, and by the daffodil and crimson of the evening 

 sky. The inimitable lines written at Ilmenau — 



" Ueber alien Gipfeln 

 Ist Eiih', 

 In alien VVipfeln 

 Spiirest Du 

 Kaum einen Hauch " — 



suggest a stillness of the atmosphere which would allow the columns 



