678 



NATURE 



\Oct. 24, 1878 



soon the yellow disappears, and nothing but a grey or 

 colourless hue is presented to my eye, although the colour 

 is still a positive and powerful red to the normal-eyed. So 

 that there is a hue of red which as a colour is absolutely 

 invisible to the colour-blind. 



If I go on beyond this point and take reds that pass 

 from crimson towards the hue called lake, I see my other 

 colour come in, a faint blue, which increases till violet is 

 reached, when it becomes more decided. 



Violet is understood, I believe, to be a compound of 

 blue with red, and accordingly, the red element being in- 

 visible to the colour-blind, violet hues generally appear 

 to them only as darkened blue. There are, however, 

 examples where, from the red being very strong, the blue 

 appears to lose its effect, and the impression given is 

 colourless, black, or grey. They correspond, in fact, with 

 the neutral red before described, although still called 

 violet or purple by the normal-eyed. This latter effect is 

 much enhanced under the artificial light of gas or 

 candles. 



A similar explanation will apply to orange, a combina- 

 tion of red and yellow, in which the yellow only is 

 perceived. 



The appearance of green to the colour-blind corre- 

 sponds exactly to that of red ; green in its true aspect is 

 invisible to them, and consequently when neutral, i.e.^ 

 unmixed with any other colour, it presents to their eyes 

 he appearance of grey. When, however, it is mixed with 

 yellow (and most of the greens in nature are yellow 

 greens) they see the yellow only, but diluted or darkened 

 by the invisible green element. And in the less frequent 

 cases where the green is mixed with blue, they see the 

 blue only, in like manner. 



It may now easily be understood how it is that so 

 simple a. defect of vision gives rise to so complex a series 

 of symptoms as those already described. 



Take first the colour red. If it is a scarlet variety, as 

 the majority of reds are, presenting the appearance of 

 yellow to the colour blind, they may naturally confound 

 it with the latter colour, as well as with orange, with 

 yellow green, and with brown, all which cause to them 

 the same sensation. If, on the other hand, the red con- 

 tains a predominance of blue, it may be confounded, on 

 the same principle, with blue or violet. If it is a neutral 

 red, lying between the two, it will be confounded with 

 black or grey. A pale pink, though very distinctly 

 coloured to the normal-eyed, often offers so little colour 

 to the colour-blind as to be mistaken for white, or very 

 light grey. 



The same explanation will apply to green. Its yellow 

 varieties may be confounded with red, orange, yellow, 

 and brown, its blue varieties with blue and violet, and its 

 neutral hue with black or grey, or if very pale, with 

 white. 



The confusion of orange with yellow, and of violet 

 with blue, black, and grey, have been already sufficiently 

 explained. 



I must now go on to show how the hypothesis of 

 Colour Blindness may serve to explain or account for 

 the anomalies in Homer's descriptions of colour. It is 

 out of my province to meddle with any questions of 

 classical scholarship, I adopt all Mr. Gladstone's critical 

 nterpretations, and I suppose I need not desire a higher 

 authority. It will be convenient to refer to his two essays 

 indiscriminately, using the letter N. for the article in the 

 Nineteenth Century, and H. for the chapter in the Studies 

 on Homer. 



Before going into any detail I may notice the general 

 classification which Mr. Gladstone (H. 458, &c.) has 

 given of the Homeric peculiarities, and it is impossible 

 not to see, at a glance, how exactly this corresponds with 

 •what might be expected from the colour-blind. 



I. The paucity of Homer's colours. Excluding black 

 and white, Mr. Gladstone reduces them to four, intimating, 

 however, in the following sentence, that even this number 

 is too many. 



The colour-blind list is limited to two. 



II. The use of the same word to denote not only 

 different hues or tints of the same colour, but colours 

 which, according to the normal-eyed, are essentially 

 different. 



This is the shibboleth of the colour-blind defect. 



III. The description of the same object under epithets 

 of colour fundamentally disagreeing one from the other. 



Mr. Gladstone only names three instances, referring 

 to iron, to the dragon, and to a thunderbolt, none of 

 which appear to me to be very conclusive ; but since a 

 colour-blind person may, with perfect correctness ac- 

 cording to his own sensations, describe grass as either 

 green, red, orange, or yellow, the defect will amply 

 account for this peculiarity. 



IV. The vast predominance of black and white ; and 



V. The slight use of colour, as compared with other 

 elements of beauty for the purpose of poetic effect, and 

 its absence in certain cases where we might confidently 

 expect to find it. 



Nothing can be more natural than this, in the case of a 

 writer to whom the great mass of colours in nature are 

 invisible. 



When we go into detail, and review the instances Mr. 

 Gladstone has given of Homer's particular applications 

 of colour adjectives, the correspondence with the colour- 

 blind hypothesis becomes much closer and more con- 

 clusive. 



As a general preliminary, let us ask what such a writer, 

 if colour-blind, might be expected to do ? How would he 

 be likely to use his epithets of colour ? 



In the first place he would be certain to use them 

 incorrectly, that is, in a way not consistent with the ideas 

 ordinarily attached to them. He must adopt words in 

 ordinary use ; but he can form no proper idea of their 

 meaning, and, as the objects they apply to appear under 

 totally different aspects to him, his use of the words must 

 necessarily be confused and often inappropriate. This 

 may be particularly looked for in regard to red and green ; 

 terms which, although conveying ideas so positive and 

 unmistakable to the normal-eyed, have to the colour- 

 blind no definite signification at all. 



But secondly, there ought to be a certain consistency 

 and intelligibility in his use of the terms when viewed in 

 regard to his own sensations ; and if my view of the 

 simple and uniform character of the disease be correct, 

 we ought to be able, knowing what these sensations are, 

 to form a tolerable idea how colour epithets would be 

 applied so as to accord with them. 



Omitting all considerations of white, black, or grey, 

 and confining ourselves to colour proper, we know that 

 every coloured object in nature presents to the colour- 

 blind person one of two sensations, either that of yellow 

 or that of blue, modified in tone or shade, as I have 

 described. These are positively distinct from each other, 

 and are never confounded. We therefore ought to ex- 

 pect that the colour-epithets used by such a person 

 should be found capable of being arranged in two groups 

 or classes, one corresponding to the yellow sensation, the 

 other to the blue sensation. The various words in either 

 group may have very different meanings to the normal- 

 eyed, but if they all convey the same sensation to the 

 colour-blind person, he may be expected to use them 

 indiscriminately. And, moreover, he ought never to 

 apply a word belonging to one class or group, to an 

 object belonging to the other group ; if he did he would 

 fail in the consistency to his own sensations which I am now 

 insisting on. For example, if a person applied the word 

 " orange," a word belonging to the yellow group, to lapis 

 lazuli, or the violet flower, which, on the colour-blind 



