There are a total of 96 carefully labeled vials of these things in the collection, and I can't find a screw thread on any of them. They all seem to be variations on this theme of a stepped cylindrical pin or pivot.
At this point the folks at the museum don't know any more about these things than I do, but they're eager to find out.
So I thought I'd pose the question to you folks: What are these things and how are they used?
--Rik





Technical info about the photos:
1. Canon T1i with MP-E 65 at 1:1, f/16, 580 EX II Speedlite with paper towel diffuser. Stacked from 9 frames handheld.
2. Same, single frame.
3. Canon A710, available light.
4. Same.
5. Same, macro mode.