year there in easy confinement. Among his visitors while a prisoner in London was Meighan, a catholic publisher. From him Hay heard for the first time arguments in support of the doctrines of the Roman church.
After the passing of the Act of Indemnity in June 1747 he was set at liberty and returned to Edinburgh, but to avoid being called as a witness against his late associates he withdrew to Kirktown House, near Kilbride, the seat of his relative, Sir Walter Montgomery. The casual discovery in the library there of Goter's ‘Papist Misrepresented and Represented’ deepened the impression made by Meighan's arguments. On returning to Edinburgh he attended the fencing school of John Gordon of Braes, who introduced him to John Seton the jesuit. Seton, after giving him a regular course of instruction, received him into the catholic church, 21 Dec. 1748. He now resumed his medical studies under Dr. John Rutherford, who had commenced a course of clinical lectures in the Royal Infirmary. On 14 Oct. 1749 he was elected an ordinary member of the Royal Medical Society, and on 2 Dec. following an ‘honorary member by succession’—a class of members which has since fallen into abeyance. Being debarred by the penal laws from graduating and obtaining a diploma, he kept a chemist's shop in Edinburgh for a year. Afterwards he became surgeon on board a ship fitted out by a company of Leith merchants for the Mediterranean trade, but his engagement terminated on his arrival at Marseilles. Before his departure he had been introduced in London to Dr. Richard Challoner [q. v.], vicar-apostolic of the London district, who had persuaded him to embrace the ecclesiastical state, and had written to Bishop Smith at Edinburgh to secure a place for him in the Scots College at Rome. From Marseilles he therefore went to the Scots College at Rome, which he entered 10 Sept. 1751. He was ordained priest by Cardinal Spinelli, 2 April 1758. On 20 April 1759 he left the college for the Scotch mission, in company with the Rev. John Geddes [q. v.] and the Rev. William Guthrie. They reached Edinburgh on 15 Aug.
In November 1759 Hay took up his residence with Bishop James Grant (1706–1778) [q. v.] at Preshome in the Enzie of Banff, where he laboured as a missionary priest till August 1767. He afterwards spent two years in Edinburgh, settling the affairs of Bishop Smith. He was consecrated bishop of Daulis in partibus, and coadjutor cum jure successionis to Bishop Grant at Scalan, 21 May 1769, and continued his services at Edinburgh as procurator for the clergy and pastor of the secular mission there.
On the death of Bishop Grant, 3 Dec. 1778, he became vicar-apostolic of the lowland district of Scotland. In the following year intense excitement prevailed among the protestant population in consequence of the proposal of the government to relax in a slight degree the penal laws against the catholics. The new chapel-house in Chalmers' Close, near Leith Wynd, Edinburgh, was burnt down by the infuriated mob, 2 Feb. 1779, and next day the rabble plundered the chapel-house in Blackfriars Wynd. During these riots the bishop incurred great personal danger. His papers were saved from the fire, but his furniture and a valuable library, formed by three of his predecessors, were partly burnt and partly distributed by public auction among the populace. He came to London to obtain from the government protection for the suffering catholics. Burke interested himself in the matter, and in a letter to Patrick Bowie spoke highly of Hay. The government, after protracted negotiations, refused protection, but compensation was granted for all losses in consequence of the riots, half the amount being paid by the government and half by the city of Edinburgh. Hay returned to Scotland at the end of June, but it was thought prudent for him to avoid Edinburgh. He had petitioned the holy see for a coadjutor, and John Geddes [q. v.] was nominated on 30 Sept. 1779.
In 1781 he went to Rome to lay before the pope a plan for reorganising the Scots College there. The suppression of the jesuits had done the college serious injury. Hay's chief object was to get Scottish superiors appointed; but although he was well received in Rome, where he remained six months, some years elapsed before the whole of his plan was carried out.
In 1788 he took charge of the ecclesiastical seminary at Scalan in the Braes of Glenlivat, but he was recalled in 1793 to resume his former functions, in consequence of Bishop Geddes's failing health. The loss of all the continental establishments belonging to the mission in the French revolutionary war was a severe trial. With very slender means he began and completed a new seminary at Aquhorties, near Inverury, Aberdeenshire, to which the students removed from Scalan, 24 July 1799. Dr. Alexander Cameron [q. v.], principal of the Scots College in Spain, was appointed his coadjutor in Geddes's place, but did not arrive in Scotland till 20 Aug. 1802. Hay's request for permission to resign his episcopal charge entirely was refused by the pope. He accordingly retired to Aquhorties,
