"Barn Find" Brass Barrel Lens Mystery!

[Dugan]

In my travels, I recently found a very rough brass barrel mystery lens.
Diameter of barrel is approximately 2 5/16", length is approximately 3 5/16".
Only engravings are a matching "1876" on both barrel and outer rim of rear lens.
Front lens is missing. Rear lens is jammed/crossthreaded into barrel. Lens rim is pretty beat up, glass is very dirty and has a couple of tiny chips near the edge.
Can anybody please help solve this mystery?
See pics.

[Mark Sawyer]

Not much to go on. Is it a Petzval or a Rapid Rectilinear? A cemented rear element is a Rapid Rectilinear, air-spaced is Petzval. Any engraved numbers or markings on the rear rim (aside from the 1876) could mean a soft focus adjustment.

If you can get the lenses out of their mounts, there may be manufacturer's markings penciled on the edge. That's about all I can offer...

[Dugan]

Thanks, Mark.
The glass is really dirty, and I don't want to make it any worse by trying to clean it. I've tried removing the lens, but it is jammed in there tight.
It appears to be air-spaced.
I got it cheeeeeap...hoping someone would say, "Oh, lens 1876! That's the only known example of a Petzval Wide-View Telephoto KinoPlastic made by Ephraim Schnitzengruber and Sons before Mr. S. ran off to join the French Foreign Legion. It's been missing all these years, it's Priceless!".

[goamules]

It's fun to research old brass, but without some engraved words it's pretty hard. I have had a few dozen that I have never placed. Even have an old lens reversing prism that I thought might be daguerriean, but couldn't confirm. I asked the famous collector Matt Isenburg if he though it was 1850s, but he didn't think it was that old. No markings, I'm never going to figure it out.