Now that is interesting.
Wonder what the underlever set-up was. Could not be a Jones screw grip as that came along in 1859.
Even more interesting, there is no trace of W W Forsyth in any of the scribblings by Greener,Burrard,Teasdale-Buckall, David Baker,Ian Crudgington, Nigel Brown etc etc. Even the late Geoffrey Boothroyd, who I sometimes did research for, makes no mention of him.
Really p'd off that Crudgington & Baker missed him, I have always had the utmost confidence in their research.
Ah well, you live & learn (every day)
