In 1763 he accompanied James Johnston, the Lieutenant-Governor, to Menorca as chaplain and secretary, and held the same post under succeeding governors.
His health was poor, and he settled down to a literary life, undertaking the education of Thomas Steele, and his brother Robert.
[1] Clarke's first publication was a poem in Greek hexameters, on the death of Frederick, Prince of Wales, in the Luctus Academiæ Cantabrigiensis, 1751.
He produced Letters concerning the State of Spain … written at Madrid during the years 1760 and 1761, (1763), with details and statistics; and A Defence of the conduct of the Lieutenant-governor of the Island of Menorca, in Reply to a Printed Libel (London, 1767).
His only daughter, Anne, was married to Captain William Standway Parkinson, RN (1769–1838), who was with Nelson at the battle of Trafalgar.