old lenses

[Chuck Heiney <cheiney@xxxxxxxxxxxxx>]

I thought I'd put this out to the members of this list. I would like  
to find a source fora lens, preferably in working condition, that  
would be of the sort that the mid to late 19th century photogs -  
O'Sullivan, Jackson, et al - would used for their landscapes. Or does  
anyone have any idea what a modern day equivalents would be in focal  
length and aperture - especially the widest opening. Ultimately I'd  
like to experiment with this old glass on a medium format digital back.

Thanks,

Chuck