Boyle, John (1707–62), 5th earl of Orrery, 5th earl of Cork , and 2nd Baron Marston , writer, was born 13 January 1707 in Westminster, London, the only son of Charles Boyle, 4th earl of Orrery, and of Lady Elizabeth Boyle (née Cecil). His birth has also been dated 2 January; the difference possibly reflects Old and New Style dating. He was educated by Elijah Fenton, poet, and at Westminster School; he matriculated at Christ Church, Oxford, on 16 August 1723 and was created MA in 1743. He was made FRS on 23 October 1746. On 9 May 1728 he married Lady Henrietta Hamilton, daughter of the earl of Orkney; a family disagreement followed, possibly because the young man refused to allow his wife to countenance his father's mistress. In the ensuing estrangement, the father willed his valuable library to Christ Church, Oxford, stating that his son could not appreciate it; a reconciliation just before his father's death (1731) was not in time to allow the insult to be withdrawn.
The new earl had to pay his father's debts, and had difficulties with the family estates in Ireland. His wife died (22 August 1732) while they were in Cork; around the same time, Boyle made the acquaintance in Dublin of Jonathan Swift (qv) and, through him, of Alexander Pope, and attempted to disprove his father's allegation by dabbling in literature. He published (1741) a translation of Horace's first ode; he also translated the letters of Pliny the Younger (2 vols, 1751), and wrote a life of the earl of Monmouth (1759) and several verse epistles and essays in two periodicals, the World and the Connoisseur.
He is remembered chiefly for his somewhat unfavourable Remarks on the life and writings of Jonathan Swift, in a series of letters to his son, which were first published in 1752. Some of Swift's friends found them very offensive, and Patrick Delany (qv), formerly intimate with Boyle, publicly rebutted his criticisms of Swift's character. The book was, however, republished several times, and there was also a German translation. Letters from Italy in the years 1754 and 1755, published posthumously (1774), and his collected letters (published in 1903 as The Orrery papers) are of interest, revealing much of his own personality. Boyle's literary talents were fairly slight, though he was generally popular.
His second marriage (30 June/30 July 1738) was to a great heiress, Margaret, daughter of John Hamilton of Caledon, Co. Tyrone. Boyle spent some years in Caledon, improving the estate and laying out gardens; though he disliked public life, he took some part in activities in the British house of lords, opposing Walpole. In 1753 he succeeded to the title of earl of Cork. His second wife died 24 May 1758; the elder son of his first marriage died during his lifetime, another son died in 1764, and the titles passed to his only son by the second marriage. There was also a daughter of the first marriage and two of the second. Boyle died 23 November 1762 at Marston, his English estate in Somerset, and was buried there.