> Here's a silly question.....

ok, here's a silly answer: not while you're driving!!! :)

> Has anyone ever heard of those lenses causing a fire or
damaging the interior
> by focusing the sun's rays onto a small area?  I've seen people
use those
> fresnel lenses to burn ants or cook stuff, and wondered if my
cargo area
> might spontaneously combust.  I can just imagine......
> ....Driving home from filling the gas can for my lawnmower, the
can sitting
> in the back of the van, driving along on a sunny day......BOOM!

not likely ... at least, not in my experience. i've had one on
the back of my 88 since it was new. in alabama summers, you'd
think it would have happened by now if it was capable of
happening.

but then, i put my gas can by the sliding door, not over the
engine!! ;)

joel