lens

[59wash]

what is it ? it is 15 1/2"dia 2 1/2 thick could start a fire on cloudy day 814 603 1781

[gibsontool]

Maybe a lens that was mounted over top of a large diameter ships compass ?

[rod]

looks like it swiveled

[rusty]

It is rather thick, so it's focus length is going to be very short, perhaps a searchlight lens?

(Magnifying a compass that is already 15 inches wide doesn't seem usefull..)

[rod]

maybe lighthouse

[Fins/413]

Lighthouse lens are usually Fresnel type

[gibsontool]

gotta agree with you Rusty, your idea sound logical

[scottg]

surely it must be some kind of stage lighting?
    yours Scott

[Brophy]

surely it must be some kind of stage lighting?
    yours Scott

Good thought but I've never seen brass on any stage equipment.

Brass/bronze sez marine or medical/scientific to me.

...Rob

[OilyRascal]

Brass also suggest explosion proof/non-sparking environment to me.

[Brophy]

This looks similar....





http://curiousscience.com/1/Scientific/Large-magnifier-on-stand-P347.html

I've made a few of these over the years for stage props.

...Rob

[Mel Larsen]

I probably wouldn't take much of a light behind that lens to make a real bright spot light??????????
Mel