Tape backup / Bizzare Device Question
dscheidt at panix.com
Tue Mar 7 14:17:44 UTC 2006
On Tue, Mar 07, 2006 at 02:09:40PM -0000, Graham Bentley wrote:
> Description: Glass bulb, similar to light bulb but with
> narrow end flared at bootom so it standsup. Inside,
> a rotating wire device that has 4 squares of card like
> material attached, like vanes.
> One one side they are black on the other they are white.
> When the sun shines brightly enough, the white side reflects
> the light energy and the black side absorbs it. The vanes
> spin around.
> This does exist and has a name and I know there are
> some very knowledgeable people on this list who will
It's called a radiometer. I've seen them called other things, like a
"lightmill" or a "light gauge".
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