Identifying a B&L brass lens

Hello everyone,

I'm an old veteran of APUG, but drifted away for a couple of years due to being overtaken by life. I've recently moved and started to re-establish a darkroom, and I've inherited a bunch of gear that formerly belonged to my great-grandfather, an old pro who did mostly ULF landscapes in his spare time.

Among that bunch of stuff is a mystery lens: a black-painted brass B&L lens, marked at f/12.5, with no markings other than the aperture scale and "Bausch & Lomb Optical Co./Rochester, N.Y." Based on focusing at infinity I think it's a 23" lens, and based on the range I guess the aperture scale is in f-stops---it goes from 12.5 to 64. I looked through some of the B&L catalogs at cameraeccentric.com, but couldn't find anything at f/12.5 other than wide-angles.

A couple of images are attached. Does anyone have an educated guess as to what I've got here?

Thanks in advance

-NT

Nathan, the most likely is a process lens, if so probably an Apo Tessar type. Or it could be a Ser. IV Protar. Count reflections to check. If Tessar, four strong reflections from the front cell, two strong and one weak from the rear cell. If Ser. IV Protar, two strong and one weak from each cell. See the 1904 B&L catalog here: https://www.pacificrimcamera.com/rl/rlBauschLombMisc.htm

Check the catalogs at http://www.piercevaubel.com/cam/catalogslenses.htm

Thanks! I find two strong and one weak reflections from each cell, so maybe it's a Ser. IV Protar. Unfortunately I have nothing larger than 8x10 on which to exercise it; the catalogs seem to indicate it was intended as a wide-angle for 16x20.

-NT