COLOUR-BLINDNESS 



COLQUHOUN 



365 



in about 4 per cent, of ih.- maleH (or one in 

 twenty-live), uml !.- than <)"> per cent, of the 

 j.-in:ilf- in those couutrieH. Now red and green 

 Are the very colours which are most largely used 

 for iln- purpose of signalling both at sea and on 

 railways : an. I it must he obvious that most dis- 

 astrous results may follow if the person whose duly 

 it is bo distinguish them from each other is unable 

 to .to so. It is then an important practical ques- 

 tion how the defect may best be recognised. 

 Authorities on the subject are agreed that any test 

 which requires the naming of colours is unsatisfac- 

 tory, aim that for two reasons. First, a person 

 may perceive colours correctly, but may make 

 mistakes through imperfect knowledge of their 

 names ; second, a person may be colour-blind, and 

 yet by his perceptions of different brightness in the 

 te-ts, may name the colours correctly. The most 

 perfect test yet devised is known by the name of 

 its introducer, Holmgren of Upsala, and consists in 

 a number of skeins of wool of different shades. 

 One of. these is placed before the person to be 

 tested, generally in the first instance a pale green, 

 and he is asked to select from the remainder those 

 which most resemble it. If colour-blind, he is sure 

 to pick out some of the 'confusion colours,' pale- 

 .grays, hull's, Ac., to match the green ; and further 

 .similar tests may then be applied to determine 

 more precisely his defect. Within recent years the 

 importance of this defect has been recognised by 

 the railway companies and the Board of Trade 

 in Britain ; though the tests applied are not in 

 either case so satisfactory as is to be desired, 

 as they consist in requiring the candidate to 

 a 'inie coloured cards, lights, &c. Moreover, the 

 Board of Trade examination is required only of 

 men applying for certificates as mates or masters 

 of vessels ; there is no compulsory examination 

 of ordinary seamen, though one of their most 

 important duties is to keep a lookout at night for 

 signal-lights, many of which are red and green. 

 This arrangement is also productive of much hard- 

 ship to those unaware of their defect, who have 

 spent valuable years in the drudgery of preparation 

 for a calling to which colour-blindness should be an 

 absolute disqualification, and only find out their 

 unfitness when they should begin to reap the 

 reward of their labour. Further, in certain cases 

 colour-blindness does not prevent the granting of 

 a certificate by the Board of Trade ; the fact that 

 its holder is colour-blind is indorsed upon it, but 

 he is permitted to act as master or mate notwith- 

 standing, if he call find a shipowner to employ him. 

 There are difficulties in the way of substituting 

 any other colours than red and green for signals. 

 Blue and yellow are the only others sufficiently 

 definite and contrasted for the purpose. But blue 

 is much more quickly lost in passing through the 

 air than other colours ; and yellow is just the 

 colour to which haze or distance reduces white. 



Colour-blindness more or less complete may also 

 occur ;ts the result of disease of the eyes, particu- 

 larly atrophy of the optic nerve and excessive use of 

 tobacco. See EYE (vol. iv. p. 513), and AMAUROSIS. 

 In the former, the distance from the direct line 

 of sight at which colours can be recognised is 

 diminished ; in the latter, the colour of a small 

 disc is not recognised when it is in the direct 

 line of sight, though it may still he perceived 

 at a little distance from it. As in the latter case, 



the perception of red ;illd jjreen is specially aflect ed, 



its presence in engine-drivers, \-o. may cause even 

 greater risk than the congenital form of colour- 

 blindness. For further information, see the Brit. 

 Assoc. Report (1886); Roy. Soc. Report (1892); 

 and works on colour-blindness and colour-vision 

 by Jay Jeffries (Boston, U.S.), Eldridge Green 

 <1891), and Abney (1895); and the writings of 



Sir David Brewnter, George Wibon, Clerk-Max- 

 well, &c. 



Colour-printing. Bee LITHOGRAPHY, PRINT- 

 ING. 



Colours, MILITARY, are the flags carried by 

 certain regiment* of the British army. Thone of 

 the infantry were originally called ensigns, a name 

 still used in the navy. In former times there wan 

 one for each company, but now there is, in each 

 Battalion (q.v.), a 'pair of colours,' one (the 

 ' Union Jack,' on a blue ground) called the royal or 

 queen's colour, is the more important, and of the 

 same pattern for all regiments ; the other, or 

 regimental colour, matches the facings of the regi- 

 ment, and has in one corner the blue union, in tiie 

 centre a wreath of roses, shamrocks, and thistles, 

 with the name, crest, and motto of the regiment, 

 and the campaigns in which it has taken part. 

 The facings of all regiments having the title 

 ' Royal ' are blue, otherwise they are white for 

 English, yellow for Scottish, and green for Irish. 

 The East Kent Regiment, formerly famous as the 

 ' Buffs,' retains the buff facings, and is the only 

 exception. English regiments have the St Georges 

 cross in red on their white colours. All colours 

 are made of silk, 3 feet 9 inches by 3 feet, fringed 

 with gold, and have crimson and gold cords and 

 tassels, on a staff 8 feet 7 inches long. They are 

 carried on parade by the two junior sub-lieutenants 

 (formerly ensigns), and guarded bv two sergeants 

 and two men, forming what is called the 'colour 

 party,' but are no longer taken into battle. 

 Since the Franco-German war of 1870-71 it has 

 been recognised that they make too conspicuous a 

 mark. The last time British colours were taken 

 into the field was in the Zulu war of 1880. An 

 officer trying to save them after Isandula, was 

 drowned in the Tugela, and the colours were 

 found wrapped round his body. Regiments of 

 guard cavalry have oblong 'standards, 30 inches 

 by 27, and dragoon regiments have ' guidons,' 

 41 inches by 27, slit in the fly, with the upper 

 and lower corners rounded off at one foot from 

 the end. These flags are all of crimson silk, 

 with gold fringe, cord, and tassels, and bear the 

 crest and campaigns of the regiment. The Royal 

 Artillery, Royal Engineers, Lancers, Hussars, and 

 Rifle regiments have no colours. When a regiment 

 obtains new colours, they are usually solemnly 

 presented by a royal personage or some lady of 

 distinction, with much military pomp, after a 

 special religious service. The old colours are hung 

 up in the cathedral or parish church at the terri- 

 torial headquarters. A member of the Heralds' 

 ( 'ollege is ' inspector of regimental colours.' Camp 

 colours are small flags matching the facings of 

 the regiment, to designate the part of the camp 

 it occupies. 



Colour-sergeant (so called as being a ser- 

 geant who, in addition to other duties, guarded 

 the colours) is the chief non-commissioned officer 

 in a Company (q.v.) of British infantry. On hi^ 

 efficiency its good order mainly depends, as he is 

 the channel of communication between the Captain 

 (q.v. ) and the men in almost even-thing. The 

 distinctive badge consists of crossed colours worn 

 <>n the sleeve above the Chevrons (q.v.). The pay- 

 is 3s. a day in the line, and 3s. 2d. in the guards. 

 The corresponding rank in the cavalry is troop 

 nergeant-major (corporal of horse in the Life aim 

 Horse Guards). In the 1'n.ited States army each 

 hat talion has a colour-guard, composed of a colour- 

 sergeant and seven corj>orals. The colour-sergeant 

 carries the national colours. 



Colqulioim, JOHN, second son of Sir James 

 Dolquhonn of Lun, was l>orn in Edinburgh. 6th 

 March 1805, studied at Edinburgh University, 



