Sunday, July 1, 2007

Aristotle's Sieve?

"#6: Why is it that when the sun passes through quadri-laterals, as for instance in wickerwork, it does not produce a figure rectangular in shape but circular?

"#11: Why is it that an eclipse of the sun, if one looks at it through a sieve or through leaves, such as a plane tree or other broad-leaved tree, or if one joins the fingers of one hand over the fingers of the other, the rays are crescent shaped when they reach the earth. Is it for the same reason as that when light shines throuhg a rectangular peep-hole, it appears circular in the form of a cone?"

Aristotle, Questions (Book XV)

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