And you people on the web were NO HELP AT ALL!
My brother gave me this shiny thing back in 1999 or so. He found it in the Lost Articles box at a restaurant (or bar?) he was working (or not!) at. I posted it back in 2007 on my picture page, with a plea to help identify it.
It took a child, a mere child, to make it happen!
Scroll down past the giant pic!
It turns out it is a sugar refractometer. It is for measuring the sugar content in beer, wine, and syrup. And the like. A link to how to use one.
Now, where did I hide the darn thing?