1)There is a letter listed in the archives addressed to his U. Glasgow professor written by him in 1726.
2)He was from Strabane in Ulster (near Derry) but town may be in Co.Armagh. He was a member of the Robert Hemphill family one of the three brothers that came with the plantation in 1609 migrating from Ayrshire obligated to the Hamiltons. (My line is from James one of the other two) who settled near Coleraine at Camus Juxta Bann.
3)On return from Philadelphia he eventually got a congregation in Co. Down I am sure as a New Light Presbyterian and probably in that style of congregation.