Scientific thing

[Mac53]

This was found in an old biology lab. The only marking on the box is the one painted on, and the only marking on the what's-it is a "21" on the part that could slide.
The slide is steel and the mirror angle is adjustable. The part that appears to clamp to something is all brass. It has a non-magnifying lens that swivels out and then has a stop to make it rest directly over whatever it gets clamped too. It also has the strange device with removable non-magnifying lens all around the outside and no lens in the center.

[Plyerman]

Hmph. I've not the foggiest idea.

[john k]

I've looked at this a couple of times now, and to start, with the age of the box, I would say 20s or earlier.   Plus the lack of stainless steel,  or chrome, and painted metal and brass also points to some age.   The clamp looks like it could be for attaching to a microscope.   Mirrors were used before mini lamps were available to light specimens in microscopes, and this is a pretty large mirror for that use.  With the lense that slips out of the way, one could align a slide, then bring the full focus part, the heavier magnification into play.  So my guess is a rather unique early microscope attachment.  Plus looking at the wear, it was used often, never sitting on the shelf too often. 

[BruceS]

Way back when.  I used to develop B&W film and print photo's.   I had a unit very similar to that to check the negatives grain structure.

[superzstuff]

Think it is used to focus negative on a photo enlarger when making prints. Mirror lays where paper goes and you look through eye piece and focus. Maybe??

[Mac53]

I think John K is likely the closest since it did come out of a fairly old lab. I'm definitely thinking microscope related, and to provide light seems reasonable. What would the strange, multi-sided lens be for?

[Branson]

I think John K is likely the closest since it did come out of a fairly old lab. I'm definitely thinking microscope related, and to provide light seems reasonable. What would the strange, multi-sided lens be for?

I'm leaning that way, too.  It's the mirror adjustability that leads me in that direction.  It's made to direct available light to the eye piece, which was crucial in old microscopes.

[rusty]

>What would the strange, multi-sided lens be for?

We may have the orientation wrong, imagine the mirror 45 to an above light source (lamp on the ceiling say), and the light going into one of the small openings on the side, a semi transparent sample would then be illuminated through the sample to the eye piece above.

Even better if the glass is crystal instead of ordinary glass, and polarizes the light...

I didn't find much in old journals about instruments, except one interesting comment, that Zoology instruments were typically aquired as obsolete medical equiptment...