My OSMG told me that a friend of his, another OSMG, had a Wheeler & Wilson's treadle and asked me if I might be interested in looking at it. Of course we all know what the reply was. When I took my Damascus to him yesterday he had the treadle in his shop, AKA his living room. Once I looked at the sewing machine I knew that it would be coming to live with me.
She has almost all of her original attachments and came with a copy of the manual. My OSMG says she is an earlier model No. 8 because the bobbin case is a little different than what is pictured in the manual and the bobbin winder is mounted on the treadle base. The serial number on the back slide plate is 423159 and the last patent date is 27 Aug 1878. Surprisingly the cabinet is in good shape for being 130 plus years old.
Another plus is that the OSMG gave her a good oiling and a test drive.