248 ON ACCIDENTAL OE SUBJECTIVE COLORS. 



deep bottle-green color. By caudle-light red and scarlet become more brilliant 

 and vivid. These two colors, which by day present a deep cineritious gray, 

 assume a strange brilliancy under an artificial light. Crimson loses its blue and 

 changes into a yellowish green. But it is the violet which changes most, and 

 presents the greatest difference when seen by day or by candle-light ; here there 

 is no longer a trace of blue, but it seems to be composed of yellow and red, as 

 by day it is composed of red and blue. As to yellow and orange, my vision is 

 absolutely the same with that of all the world, as seen by day or by artificial 

 light. 



" Green by daylight : I am certain that of this color I have a peculiar idea; 

 it seems to me but little different from red. In order to recognize in it a pecu- 

 liar tint I in vain place a bay leaf beside a stick of sealing-wax : hence it may 

 be safely inferred that I see green or red, or both colors, differently from the 

 rest of the world. Orange and bright green appear to me to have much resem- 

 blance. The green most agreeable to me is that which is very deep, and it be- 

 comes the more distinct as it verges upon yellow. I recognize plants as well as 

 another, and am able, like others, to appreciate their differences or resemblances. 

 Nevertheless, an infusion of tea, or a solution of liver of sulphur, whatever they 

 may be to others, are green for me ; the green cloth which covers some tables 

 appears to me brown and soiled, and I am persuaded that a mixture of brown 

 and red would, to my eyes, well replace that color ; but when such cloth begins 

 to grow old and becomes yelloAv to others, then only does it assume for me a 

 green tint. Like all the world, I find a difficulty in distinguishing green by 

 artificial light, which for me, as for others, then closely approaches to blue. In 

 all these cases I have been satisfied by numerous trials that my brother sees 

 just like myself, and therefore differently from all other persons. 



" Persuaded that cases of this kind could not fail to be of interest to inquisi- 

 tive minds, I was preparing to publish a statement of the peculiarities of my 

 vision, when I remembered having read in the Philosophical Transactions some 

 account of a mariner of Maryport, named Harris, who, it was represented, could 

 not distinguish between colors. The case of Harris seeming somewhat different 

 from my own, I thought that a comparison might cast some light on the nature 

 of our imperfection, and wrote to obtain exact details on the subject ; the inform- 

 ation received convinced me that the defects of vision in the two cases were not 

 abtfolutely parallel, and this suspicion was confirmed on my sending at least 

 twenty specimens of colored riband to Maryport, with a request that they might 

 be submitted to the inspection of Harris both by solar and artificial light. Sub- 

 sequent observation has satisfied me that cases of this nature are by no means 

 scf rare as we might suppose them to be ; in carefully studying the vision of 

 persons of my acquaintance I have found more than twenty who might be 

 ranged in the same category with myself; one or two differed only a little from 

 the others. Among twenty-five pupils to whom I was one day endeavoring to 

 explain this subject, there were found to be two affected in a similar manner ; 

 and, another day, one in the same number of auditors. Among all these persons 

 my brother and I alone could not distinguish blue from violet by daylight, 

 while, by candle-light we both recognized a great difference between these 

 colors. With regard to green, all the persons spoken of had perceptions pre- 

 cisely like our own. As has been said, however, I have observed some twenty 

 persons whose vision was similar to mine, but I have never heard of any woman 

 who was affected with the visual imperfection of which we are speaking." 



A second account, accompanied by details, is to be found in the writings of 

 Sommer, a man of eminence, who describes as follows the infirmity under which 

 he labored : 



" The sub-orbital part of my eye is very prominent, and covered with 

 thick blond hairs, which form an arch a little flattened. The folds of the upper 

 eyelids are parallel to the border of the orbit, the lower eyelids thick, and the 



