I have one. I don’t really what it does, or if people still use them, or if its worth anything? Anybody on here ever work with them, know anything about them?
Wiki gives some background on what they are and how they’re used: Geological compass - Wikipedia
Here’s a new one for sale for ~ 1000 British pounds: http://geologysuperstore.com/cocla-stratum-compass.html
So apparently they’re still made and are fairly expensive instruments. Don’t garage sale it; you won’t get $5 for it.