1 86 TEE POPULAR SCIENCE MONTELY. 



I will only mention Mulready. It is generally stated that in his 

 advanced age he painted too purple. A careful examination sIioavp 

 that the peculiarity of the colors of his later pictures is produced by 

 an addition of blue. Thus, for instance, the shadows on the flesh are 

 painted in pure ultramarine. Blue drapery he painted most unnatu- 

 rally blue. Red of course became purple. If you look at these pictures 

 through a yellow glass, all these faults disappear: what formerly 

 appeared unnatural and displeasing is at once corrected ; the violet 

 color of the face shows a natural red; the blue shades become gray; 

 the unnatural glaring blue of the drapery is softened. To make the 

 correction perfect, the glass must not be of a bright gold-color, but 

 rather of the color of pale sherry. It must be gradually darkened in 

 accordance with the advancing age of the painter, and will then cor- 

 respond exactly with the color of his lens. The best proof of the 

 correctness of this statement is, that the yellow glass not only modifies 

 the blue in Mulready's pictures, but gives truthfulness to all the other 

 colors he employed. To make the proof complete, it would be neces- 

 sary to show that by the aid of yellow glass we saw Mulready's pict- 

 ures as he saw them with the naked eye ; and this can be proved. It 

 happens that Mulready has painted the same subject twice first in 

 1836, when he was 50 years of age and his lens was in a normal 

 state, and again in 1857, when he was 71, and the yellow discoloration 

 had considerably advanced. The first picture was called "Brother 

 and Sister ; or Pinching the Ear ; " the second was called " The Young 

 Brother." In both pictures a girl, whose back only is visible, is car- 

 rying a little child. A young peasant, in a blue smock-frock, stands 

 to the right and seizes the ear of the child. The background is formed 

 by a cloudy sky and part of a tree. Both pictures are in the Kensirfg- 

 ton Museum. The identity of the composition makes the difference in 

 the coloring more striking. If we look at the second picture through 

 a yellow glass, the difference between the two almost entirely disap- 

 pears, as the glass corrects the faults of the picture. The smock-frock 

 of the boy no longer appears of that intense blue which we may see 

 in a lady's silk dress, but never in the smock-frock of a peasant. It 

 changes into the natural tint which we find in the first picture. The 

 purple face of the boy also becomes of a natural color. The shades on 

 the neck of the girl and the arms of the child, which are painted in a 

 pure blue, look now gray, and so do the blue shadows in the clouds. 

 The gray trunk of the tree becomes brown. Surprising is the effect 

 upon the yellowish-green foliage, which, instead of appearing still more 

 yellow, is restored to its natural color, and shows the same tone of 

 color as the foliage in the earlier picture. This last fact is most im- 

 portant to prove the correctness of my supposition. My endeavor to 

 explain it became the starting-point of a series of investigations to 

 ascertain the optical qualities of the pigments used in painting, and 

 thus to enable us to recognize them by optical contrivances, whrn the 



