Haliday, Alexander Henry (1727?–1802), physician and public figure in Belfast, was one of several sons of Samuel Haliday (qv), a presbyterian minister at Belfast. Intent on a career as a physician, Alexander Haliday studied at Glasgow University and graduated MA and MD (1751), after which he returned to practise in Belfast, where for nearly half a century he was a popular and influential public figure. He resided in Castle St. Of his work as a physician frequent mention occurs in the letters of William Drennan (qv) and his sister Martha McTier (qv). Haliday won great credit when he intervened with Steelboys and persuaded them to cease attacks on Belfast (December 1770). Like most contemporaries of his class in the late 1770s or early 1780s, he became a Volunteer (Belfast corps). This brought him the friendship of the earl of Charlemont (qv), whose correspondent he was from 1780 until the earl's death (1799). He corresponded too with Edmund Burke (qv). Haliday's name is mentioned in connection with almost every public undertaking in Belfast during his later years. After joining (1792) the Belfast Society for Promoting Knowledge, best known for its library, he enhanced its esteem by becoming president (11 September); he retained this office until 1798 and bequeathed his personal collection to the library, though he appears not to have attended meetings.
In his religious beliefs a non-subscribing presbyterian, Haliday referred in a letter to Charlemont on 8 March 1787 to ‘that narrow-minded bigoted body the synod of Ulster’ which ‘persecuted my father’ (Charlemont MSS, ii, 49–50). Like Charlemont a firm whig and a founder member of the Northern Whig Club (1790), Haliday considered himself to be ‘as averse as any man breathing from republican ideas and from popery’ and believed of the catholics that there were ‘tenets in their religion which lead to the subversion of the state’ (ibid., ii, 119–20). He was so struck by the reaction in Belfast to a pamphlet of Theobald Wolfe Tone (qv), An argument on behalf of the catholics (1791), as to put to Charlemont whether he would consider it prudent to unite the burning questions of parliamentary reform and catholic relief (5 November). At a meeting of the Northern Whig Club (November 1792) he was alone in voting against resolutions that ‘went fully and decidedly into the Catholic question’ (Drennan–McTier letters, i, 423). He seems to have shared Charlemont's view that Britain's war against France should be supported on the ground that Irish as well as British security depended on the exclusion of France from the Low Countries. But measures taken by the Irish government in 1793 to promote internal security – suppression of the Volunteers and prohibition of representative conventions – were not to his liking. Though he disapproved of the radicalised United Irishmen, who in Ulster were mainly presbyterians, he sympathised with William Orr (qv) and others who suffered in consequence of repressive measures taken there by the Irish government in 1797. He strongly disapproved of the Orangemen. Just after the rebellion of 1798 had been suppressed he told Charlemont, ‘the times have harden'd my heart . . . perhaps’ (quoted by Benn).
Haliday was the author of an unpublished tragedy on Lucius Junius Brutus – it was shown to Richard Brinsley Sheridan (qv) – and of odes some of which were published posthumously in the Belfast Monthly Magazine (1810–11). Haliday's health deteriorating, Drennan wrote a eulogy in anticipation of his death, which occurred on 28 April 1802 about the age of 75. A long appreciation by Henry Joy (qv) junior appeared in the Belfast News Letter. Haliday was buried at the New Burial Ground, Clifton St., Belfast. He married Martha (née McCollum) in 1754, and Anne (née Edmonstone), who belonged to a Scottish family residing at Red Hill, Co. Antrim, in 1775. Neither wife had children. In his will he made a bequest to Anne ‘for her having never given on any . . . occasion, from her early youth till this hour, any just cause to rebuke or complain of her’ (quoted by Benn). An elder son (name not ascertained) of Samuel Haliday was a collector at Charleston, South Carolina, until the American revolution, in consequence of which he removed to London, allowing one of his sons, William Haliday (1763–1838), to be trained as a physician by Alexander Haliday, who left him the best part of his fortune.