Hi cousin!! James was a son of Joseph Thackrah (1789-1855) a surgical instrument maker at Leeds & Halifax, and wife Ann Whitaker (1792-1839). Curiously James was called Joseph Henry on his death certificate. I descend from James' brother George. I corresponded with James' granddaughter Del (Adelaide) who died in 1992. Have lots more info, needs typing up, will post further message a.s.a.p.