[Sca-cooks] Farsighted lenses
TerryDecker
t.d.decker at att.net
Sun Mar 23 17:06:28 PDT 2014
424 BCE? That will be a a burning glass mentioned in Aristophanes "The
Cloud." That makes it a bi-convex lens, probably of glass but possibly of
rock crystal. The earliest known lens in the Layard lens, Assyrian rock
crystal from roughly 1000 BCE.
A source that I really would like to see on this subject is Vincent Ilardi,
Renaissance Vision from Spectacles to Telescopes from the American
Philosophical Society.
Bear
-----Original Message-----
From: Susan Lord Williams
http://en.wikipedia.org/wiki/Magnifying_glass states that “a magnifying
devise” existed in 424 BC. It does not specify whether it was glass,
crystal or clear quartz. What is the difference? - It continues to state
that “glass lenses” were produced in the Middle Ages. I assume that
magnifying lenses were available.
Medieval Muslims, including those in Bagdad and Andalusia, worked with
quartz and also they had a oops - glass or crystal factory (now that you
question it I don’t know which) outside of Cordoba by the 9th century as
Ziryab insisted that wine be drunk from glass or crystal goblets. I don’t
know enough about it to be able to say if they produced glass or crystal.
Do we have an optometrist amongst us who knows about the history of the
development of lenses?
More information about the Sca-cooks
mailing list