John Blake Corkhill certified as a surgeon 2 Nov. 1792 by the Liverpool Medical Board. He worked as surgeon on the Liverpool slaver Jenny, departing Liverpool 26 Nov. 1792 to the Congo River and then Kingston, Jamaica. He returned to Liverpool and was discharged from pay 27 Sept. 1793. He is on the Liverpool muster roll (TNA, BT98/53,315) and mentioned in the Jenny’s accounts, kept at the Clements Library, University of Michigan. He married in Cornwall in 1796 and died there in 1809.