Info on a Bausch and Lomb lens

[rosshj]

Hello,

I'm looking to find out a little more information on a lens I just found at an antique store.

It's a Bausch and Lomb. I measured (roughly) the focal length at 24" and the aperture at f6 (edit, see next comment). I didn't take it apart, but it appears to have one element in the front and two at the back.

I'm wondering if this is a petzval or triplet design and if anyone would have any extra info on it.

Thanks!

Ross