I just did a Google search. Loads of info on this gun (or guns), particularly a really LONG article by Robert Beeman. Also references to Viginia Military Institute (VMI), who may have an original. Apparently the actual L&C airgun had the reservoir on the buttstock. The "grapefruit" reservoir, mentioned elsewhere, was also common in those days. I think there are pictures of Audubon with one (you didn't think he waited for those birds to pose for him, did you? He blasted every type of bird available).