DAWN, the time when light appears (daws) in the sky. The dawn colours appear in the reverse order from those of the sunset. When the sun is lowest in both cases the colour is deep red; this gradually changes through orange to gold and yellow as the sun nears the horizon. This is their order of refrangibility, in the spectrum; the blue rays usually are scattered in the sky. The colours of the dawn are purer and colder than the sunset colours as the reduced dust content of the atmosphere causes less sifting of the light rays.