Next message: george huxtable: "Re: Night Vision Scopes"
> The obvious example is using a magnifying glass to burn holes in
> the school desk on a sunny day...
Which brings us back to refraction. Or vandalism. Can I focus a magnifying
glass through an automotive windshield to burn holes in the dashboard of
someone in my designated parking spot? <G>
Or as amateur photographers learn when they set their focal-plane-shutter
SLR's back-side down on a nearly-horizontal surface when the Sun is
high--without a lens cap; a swell way to burn a hole through the shutter
curtain.
Bill
