Curiosities of Science, Past and Present / A Book for Old and Young

by John Timbs

BEAUTY OF TWILIGHT.

This phenomenon is caused by the refraction of solar light enabling it to diffuse itself gradually over our hemisphere, obscured by the shades of night, long before the sun appears, even when that luminary is eighteen degrees below our horizon. It is towards the poles that this reflected splendour of the great luminary is longest visible, often changing the whole of the night into a magic day, of which the inhabitants of southern Europe can form no adequate conception.