I know exactly what it is. Bausch and Lomb Optical made these about 1890 and later. They put a lot of other peoples names on them. I have 3. One says Eastman Kodak Co. One says SeRoCo (Sears Roebuck & Co.), and one says Hyatt. There was one on Ebay recently that didn't sell. It actually had the Bausch & Lomb name on it. The lens Collectors Vade Mecum has this paragraph about them:
Universal Portrait f4.0 These seem to be a Petzval type made in:
No(1) 6.5, with front glass 2.75in dia. for 5x4in.
No(2) 8.5, with front glass 3.5in dia. for 5x8in.
No(3) 11.5, with front glass 4.16in dia. for 6.5x8.5in.
No(4) 13.5in with front glass 4.5in dia., for 8x10in.
The separation of the rear glasses was adjustable to control softness, and this may be most useful in close-up
as it increases the depth and eveness of definition.
Interesting but mine are all #5 I guess as they are 16" f4. The rear groups should have a single line on the inner one and 4 lines on the outer one. You turn the outer one ccw until the lines line up for 1, 2, 3, &4 diffusion.
They are a "Patent Petzval" type.
Gorgeous lenses all.