GREY RAINBOWS

Evening Post, Volume CV, Issue 142, 16 June 1923, Page 14

GREY RAINBOWS

SIX COLOUES VISIBLE TO MOST

PEOPLE.

Although we speak of sunlight as being white, it really consists of every known, hue blended together in certain proportions. This is revealed to us whenever the sun shines through rain clouds in such a way that its white beams are decomposed into the glorious spectacle of the rainbow, states "H.C.V." in the " Daily Mail." This natural spectrum, or rainbow, forms the basis of all our ideas of colour. The beautiful hues which so brighten our lives are due to the power which our surroundings hay.a ol selecting certain colour rays from the sunbeams and radiating them out to us Thus the reds radiate red and the greens radiate green sunbeams, and__so_pn, as the case may be. Hence, it conies, about that a dress which ■ looks beautiful in daylight may not look so well at night, as the colour rays contained in artificial light are not identical with those of the sun.

Light comes to us in waves, and the colour depends on the rapidity of the vibrations producing it. The red rays are the. lea.st and the violet the most rapid; between these two are all the colours we are. able to recognise.

No human eye has ever been able to see more.than seven distinct colours in the rainbow, and. very few people are able to. distinguish more than six. Our ability to appreciate colours depends on the acuteness of the colour centre in the brain. When the centre is very' badly developed one colour only is seen, and the whole rainbow appears as a dull.grey. This condition is only very rarely met with, apart from disease. Those in whom the centre. is slightly more developed can distinguish the .two colours which differ most in wave length —red and violet, with or without a neutral band in between. /

As development, goes' on, the next colour to be appreciated is green, lying midway between red and violet. The next point of greatest difference in wave length lies between the red and the green—naiiiely, yellow. People belonging to this four-unit group can see only red, yellow, green, and.violet. "The next stage.in development is reached in fiveunit people, who can see blue appearing between the green and the violet. Similarly, orange is seen between the red and yellow in six-unit people, who form the majority of mankind at the present day, and are therefore looked upon as normal. '

Some few individuals, numbering only one in several thousands, have their colour-centre so well developed that they can detect a seventh colour,' indigo, between violet and blue.