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COLOUR 



363 



was reckoned among the seven wonders of the 



world, though it was by no means a masterpiece 

 >: i.i>-i-k sculpture. It in said to have been the 

 work ui Chares of Lindus, a distinguished pupil 

 <it Lysippus, who gave twelve years to the casting, 

 .and completed liis work in 980 H.C. Its height 

 i- \.uiously given at from 90 to 120 feet. It 

 stood near the harbour; but the legend that 

 placed it astride the entrance is certainly apocry- 

 phal, and probably arose from a misunderstanding 

 of the statement that it was so high that a ship 

 illicit sail Ijetween its legs. Fifty-six years after 

 its erection it was thrown down by an earthquake, 

 and there its ruins lay, the marvel of the place, 

 till in 653 A.D. an Arab general sold them to a 

 Jew from Edessa for old metal. Other famous 

 4-olossi of antiquity were the Chryselephantine 

 <q.v. ) statues of Athena on the Acropolis, 37 

 feet, and of Zeus at Olympia, 40 feet, DOth by 

 Phidias ; the Zeus at Tarentum, by Lysippus, 107 

 feet ; a bronze Apollo, 66 feet, brought from Apol- 

 lonia to Rome by Lucullus ; and a marble statue 

 of Nero, 131 feet, set up by the emperor before 

 the palace, but removed by Vespasian to the Via 

 .Sacra, where Commodus afterwards superseded the 

 head by one of himself. Colossi came in again 

 with the Renaissance, and in later times the most 

 noteworthy have been the S. Charles Borromeo 

 <1697), on the bank of the Lago Maggiore, 72 

 feet ; the ' Bavaria ' national statue at Munich, 

 67 feet; the Arminius (q.v.) statue, 90 feet to 

 the point of the upraised sword ; the Virgin of 

 Puy, 51 feet ; the figure of Germania in the 

 national monument on the Niederwald, 112 feet; 

 and Bartholdi's ' Liberty enlightening the World ' 

 <1886), in New York harbour, 156 feet to the tip 

 of the torch. There are enormous images in Japan, 

 Polynesia, and elsewhere. See Lesbazeilles, Les 

 Colosses Anciens et Modernes (1876) ; Torr, Rhodes 

 in Ancient and Modern Times (2 vols. 1885-87). 



Colostrum. See BEESTINGS. 



Colour is not a material existence ; it is a 

 /sensation. The colour of an object varies slightly 

 with the brilliancy of the light emanating from it 

 to the eye ; and where the eye is abnormal, as in 

 the ' colour-blind,' the apparent colours of objects 

 may differ widely from their colour as perceived 

 by normal eyes. Light is due to waves or other 

 periodic disturbances whose recurrence resembles 

 that of waves in the ether of space ; and just as 

 air- waves of a certain definite frequency of recur- 

 rence will induce in the ear the sensation of a 

 sound of a particular pitch, so will the impact of 

 ' ether- waves ' of a certain particular frequency 

 induce in the eye a sensation of light of a par- 

 ticular colour. We are experimentally acquainted 

 with ether-waves whose frequencies range be- 

 tween 20,000,000,000,000 and 40,000,000,000,000,000 

 per second ; but the eye is blind to all except a 

 comparatively narrow range of these viz. from 

 392 billion to 757 billion per second. Within that 

 Comparatively small range, however, we have a 

 large choice of fractional and integral nnnitara ; 

 ana each number, each frequency, has its own 

 colour. When we look at the spectrum or rain- 

 bow we have marshalled before us a series of 

 colours, of which the extreme visible red is pro- 

 duced by about 392 billion, the extreme visible 

 violet by about 757 billion vibrations per second. 

 Between these the eye may rest upon certain dis- 

 tinctive colours, sucli as yellow, blue, and so on ; 

 and the frequencies corresponding to these respec- 

 tive colours are, taking the centre of 1 each distinc- 

 tive colour as displayed in the spectrum red, 

 492'4; orange-red, 484'1; orange, 503*3; orange- 

 yellow, 511 -2; yellow, 517*5; green, 570; blue- 

 green, 591-4; cyan-blue, 606; blue, 635 '2; violet- 



lilue, UH.VH ; juice violet, 740'5 all in billions 

 ( 1,000,000,000,000) per second. Light due to 

 wave-motion of one simple frequency would be 

 'homogeneous' or 'monochromatic light; it 

 would produce the simplest colour-sensation ; but 

 no such thing is experimentally attainable. The 

 light from burning sodium is a compound of two 

 yellow lights, very near one another in the spec- 

 trum, and corresponding to the respective wave- 

 frequencies of 508*9 and 510*6 billions per second ; 

 and this is the nearest attainable approximation 

 to monochromatic light. 



The eye takes up, singularly enough, any con- 

 geries of several monochromatic lights impinging 

 simultaneously upon the same spot in the retina, 

 and the resulting sensation is always that of a 

 single colour, not necessarily resembling any of 

 the components. The retina is composed of 

 numerous ultimate nerve-elements, each of which 

 is capable of perceiving one of three physio- 

 logically primary colours. These colours are red, 

 green, and violet (Young and Helmholtz); ver- 

 milion, emerald green, and ultramarine blue 

 ( Clerk Maxwell ) ; or red, green, and blue ( Pick ). 

 Simultaneous affection of the elements sensitive 

 to red and of those sensitive to green produces, 

 according to the ratio between the respective 

 irritations, any colour of the spectrum from red 

 through orange and yellow up to green ; similarly, 

 green and violet lights blended in different pro- 

 portions produce all the intermediate blues ; and 

 when the whole three sets of nerve-elements are 

 irritated, the sensation is still that of a simple 

 colour, or, it may be by due adjustment, of white 

 light. Coloured lights may be mixed so as to 

 show this, either by causing coloured lights from 

 different sources to coincide in the eye or on a 

 screen, or else, as in the colour-top, by causing 

 ocular impressions of different colours to succeed 

 one another in the eye with such rapidity that the 

 eye or the brain blends them. But nearly every 

 example of what we call coloured light is in reality 

 an admixture of several monochromatic lights 

 e.g. the light passing through a piece of green 

 glass is composed as will be founa on trying to 

 make a spectrum of it by means of a prism not 

 only of green light, but also of blue and yellow, 

 and, often enough, of red and violet ; but the re- 

 sultant sensation is that of green, a simple colour. 



White light is in general due to a simultaneous 

 impact of wave-motions of all visible frequencies. 

 But the sensation of whiteness may also be pro- 

 duced by the simultaneous impact on the retina 

 of two suitable spectral colours, such as yellow and 

 ultramarine blue ; and such a pair of colours are 

 said to be complementary to one another ; other 

 examples are red and greenish-blue, greenish- 

 yellow and violet, orange and cyan-blue ( a rather 

 greenish blue ). It will be observed that it is said 

 that yellow and ultramarine blue lights make 

 white light, while it is well known that yellow 

 and blue pigments make a green pigment. The 

 explanation of this is that the light from the 

 yellow pigment is not pure ; it contains green 

 light; similarly that from the blue pigment con- 

 tains green light; when the pigments are mixed, 

 the eye receives a simultaneous impression of blue, 

 yellow, and green; but the blue and the yellow 

 destroy one another, being, to the eye, comple- 

 mentary colours ; jointly they produce white 

 light ; and thus the green alone remains, diluted 

 with white. Complementary coloured lights may 

 both or either be of any degree of complexity ; if 

 an aggregate impression of blue light ana an 

 aggregate impression of yellow be superimposed 

 on the same part of the 'retina, whatever be the 

 mode of their production, the result may be the 

 same an impression of wliite light. 



