He inherited the title of Earl of Dumfries in 1742 , upon the death of his mother Penelope Crichton , 4th Countess of Dumfries .
William Dalrymple - Crichton , 5th Earl of Dumfries KT ( 1699 -- 27 July 1768 ) was a Scottish peer .
William Dalrymple - Crichton inherited the title of Earl of Dumfries in 1742 , upon the death of William Dalrymple - Crichton 's mother Penelope Crichton , 4th Countess of Dumfries .
William Dalrymple - Crichton , 5th Earl of Dumfries KT ( 1699 -- 27 July 1768 ) was a Scottish peer .