The ancient Greek Pythagoreans of the 5th century BC believed that the sun was a gigantic crystal ball larger than the earth, which gathered the ambient light of the surrounding cosmos and refracted it to earth, acting as a giant lens.
A giant lens? In the 5th century BC?
Perhaps it was because nobody until now has been willing to recognise that lenses existed in antiquity, and that the crystal sun idea was overlooked, and has never been described in any books on the history of science or philosophy.
However, it appears in my latest book The Crystal Sun, the paperback of which is published by Arrow (London) in Britain and Australia on 1 February. The hardback, from Century (London), has been available in Australia since May, 2000.
What, then, is all this about ancient lenses? Surely some mistake?!
The fact is that I have located more than 450 ancient lenses in museums all round the world, and I even own a Greek crystal lens of the 6th century BC myself.