INSENSIBILITY TO COLOURS. 31 



sometimes baffled in distinguishing a full purple 

 from a deep blue, but that he knows light, dark, 

 and middle yellows, and all degrees of blue except 

 sky-blue. " I married my daughter to a genteel, 

 worthy man, a few years ago ; the day before the 

 marriage, he came to my house dressed in a new 

 suit of fine cloth clothes. I was much displeased 

 that he should come, as I supposed, in black, and 

 said that he should go back to change his colour. 

 But my daughter said, No, no ; the colour is very 

 genteel ; that it was my eyes that deceived me. 

 He was a gentleman of the law, in a fine, rich, 

 claret-coloured dress, which is as much black to 

 my eyes as any black that ever was dyed." Mr. 

 Scott's father, his maternal uncle, one of his 

 sisters, and her two sons, had all the same im- 

 perfection. Dr. Nich&l has recorded a case where 

 a naval officer purchased a blue uniform coat and 

 waistcoat with red breeches to match the blue, 

 and Mr. Harvey describes the case of a tailor at 

 Plymouth, who on one occasion repaired an 

 article of dress with crimson in place of black silk, 

 and on another patched the elbow of a blue coat 

 with a piece of crimson cloth. It deserves to be 

 remarked that our celebrated countrymen, the 

 late Mr. Dugald Stewart, Mr. Dalton, and Mr. 

 Troughton, have a similar difficulty in distinguish- 

 ing colours. Mr. Stewart discovered this defect 

 when one of his family was admiring the beauty 

 of a Siberian crab-apple, which he could not dis- 

 tinguish from the leaves but by its form and size. 

 Mr. Dalton cannot distinguish blue from pink, 

 and the solar spectrum consists only of two 

 colours, yellow and blue. Mr. Troughton regards 

 red ruddy pinks, and brilliant oranges, as yellows, 



