Thanks Andrew & Dan (who responded via pm). It looks like the lens is from 1881. It is not marked as a Euryskop. I believe it is the original Petzval design. I just disassembled it and cleaned the lenses and the rear group is not cemented. Physically it is about 8.5" long with 4" barrel. Flange OD is ~5.25" The rear group is about 3.125" in diameter and the infinity focus is 12" from the waterhouse stop slot (or about 9" rear focus). 12"/3.125" give f/3.8 for the max aperture. I figure it is probably a lens intended for full-plate. The hood & barrel is a little chewed up but the focus is silky and the glass is very clean for a lens of this vintage. I'll have to slap it on my 11x14 and see what it covers and if it is swirly.
It is marked:
5A
No.25851
Voigtlander & Sohn
Wien,
Braunschweig
It is marked:
5A
No.25851
Voigtlander & Sohn
Wien,
Braunschweig