Here is a beautiful little McIntosh Stereopticon Petzval lens.
This is a 12 inch f7.7 lens. Best for Portraits in the 8X10 format, but it would also be lovely on 5X7 and 6.5X8.5.
It was made over 100 years ago by the Bausch & Lomb Optical Co. I know this only by experience and family resemblance. It doesn't say B&L anywhere.
It comes with a clamp that can be drilled and mounted to a wood board and work very well as a flange. Glass is excellent.
Beautiful tack sharp center and lovely drop-off / bokeh. Good things can come in small packages. $225.00 + shipping