MacNeven (MacNevin), William James (1763–1841), physician, scientist, and United Irishman, was born 21 March 1763 at Ballynahown, near Aughrim, Co. Galway, the eldest of the four sons of James MacNeven and his wife Rose (née Dolphin). Rose MacNeven died young and James not long afterwards (1769?), leaving their children to be raised at Ballynahown by James's widowed sister, Mary Brennan, a dutiful and pious catholic – she wore round her neck a small silver case containing what was said to be a piece of the true cross. At the age of ten or so William James MacNeven went to Prague in Bohemia (a possession of the Austrian Habsburgs) to live with an uncle, James MacNeven's elder brother, a court physician, Baron William Hugh MacNevin–O'Kelly (qv). The baron, who owned a very fine house in Prague and a castle at Srutsch (Zruc), belonged to a scientific circle into which the young William was drawn. He attended classical and medical colleges in Prague (admitted to study medicine 15 January 1781) and went on to complete his medical studies and qualify in Vienna (2 June 1785). His return journey to Ireland began in June 1786; it was apparently broken for some months in London, where he was admitted a licentiate of the Royal College of Physicians (2 April 1787). When he returned to Ireland is not known, but he is listed in Wilson's Dublin Directory as practising as a physician at 115 Capel St., Dublin (1789) and then at 16 Jervis St. (1790–98). He was visiting physician to the House of Industry (1790–98). Among his acquaintances in Dublin were the state physician, Dr Robert Emmet (qv), and the chemist Richard Kirwan (qv). A close friend was Emmet's son Thomas Addis Emmet (qv). MacNeven was elected MRIA (27 November 1790) and was briefly secretary (11 June 1791–16 March 1792), the first catholic to attain office in this learned society. He was to be expelled nine years later ‘having confessed himself a traitor’ (16 March 1799) (RIA, Mins, i, 146).
MacNeven's political activities began formally when he was elected to the Catholic Committee as a delegate from Navan – at the instigation of his friend Dr Edward Sheridan who lived there (9 February 1791). On the committee he supported the faction led by Edward Byrne (qv) and John Keogh (qv) in opposition to Viscount Kenmare (qv). At the Catholic Convention (December 1792), at which he also represented Navan, he made two speeches – published with others in a pamphlet, A brief account of the general meeting of catholic delegates December 1792 (1793) – advocating the same franchise for catholic freeholders as for protestants (40s.), though other delegates considered a £20 franchise acceptable. The catholic relief act passed some months later provided for a 40s. franchise. MacNeven was probably at the inaugural meeting of the Dublin Society of United Irishmen (9 November 1791), as he dined two days before with a group of democrats planning that meeting – including James Napper Tandy (qv), William Drennan (qv), Theobald Wolfe Tone (qv), Richard McCormick (qv), Thomas Russell (qv) and Samuel Neilson (qv); but he was never active in the society, so inactive that Thomas Collins (qv) reported to Dublin Castle in 1794: ‘he seldom attends’. The prospect of a reforming whig viceroy, Earl Fitzwilliam (qv), revived his political consciousness. He was one of a committee of nine appointed at a meeting of Dublin catholics (23 December) to draw up and circulate throughout Ireland a petition seeking catholic emancipation. In a speech at a well-attended public meeting organised by Dublin catholics in response to Fitzwilliam's abrupt recall (late February 1795) MacNeven criticised Ireland's connexion with Great Britain (9 April). MacNeven's politics did not, however, prevent him having friendly relations with Lieut-col. James O'Moore, commanding officer of one of the six catholic regiments (Fitzjames’ or Berwick's) commissioned (1794) to employ in the British army Irish officers (catholics) who had left the French army out of loyalty to the Bourbons; through him he obtained for his brother Hugh MacNeven (d. mid 1797), who had followed him to Prague and studied medicine, a commission as surgeon in that regiment (1 Oct. 1794).
Towards the end of 1796, W. J. MacNeven was sworn into the radicalised and militarised United Irishmen and in October or November, at the instigation of Lord Edward FitzGerald (qv), he became a member of the national directory. In April 1796, Tone, in Paris aiding the French government in its preparations for an invasion of Ireland, had included MacNeven in a list of nine men a proposed French emissary, Eugene alias John Aherne (qv), should meet in Dublin. Though Aherne did not reach Dublin, another emissary, Bernard MacSheehy (qv), did. MacNeven was one of three or four United Irishmen whom MacSheehy met secretly on 27 and 28 November 1796. MacNeven himself was appointed an emissary of the United Irish national directory in June 1797. Leaving Ireland on the 27th, he travelled to France via Yarmouth and Hamburg, delivering there a memorandum to the French minister, and arriving in Paris to be introduced by Edward Lewines (qv) to the Directory (August). On his return journey he called at Wetzlar on General Lazare Hoche, who promised that 10,000 troops would soon sail for Ireland, and in London on Lord Edward FitzGerald to pass on this news; but Hoche's death (19 September) prevented him from mounting a second expedition to Ireland. The national directory planned a rebellion for 1798 but before it began almost all its members were arrested and held as state prisoners. MacNeven was taken at his lodgings in Inns Quay (12 March 1798) and held at Kilmainham. As the rebellion was being suppressed and so its leaders’ lives put in danger, MacNeven and two other United Irish leaders in custody, T. A. Emmet and Arthur O'Connor (qv), offered a ‘confession’ provided that they should not incriminate others and that lives be spared (26 July). MacNeven was examined by secret committees of the Irish houses of lords and commons (7, 8 August). With other state prisoners he was removed to Fort George in the north of Scotland (February 1799). At Fort George, where the prisoners had an unusual amount of freedom, he showed an interest in the Gaelic traditions of Scotland, gave fellow prisoners lessons in French, and even compiled for their use a French grammar.
After his release (30 June 1802), forbidden to return to Ireland, MacNeven visited old friends in Bohemia, made a pedestrian tour of Switzerland, of which he wrote an account, A ramble through Swisserland in the summer and autumn of 1802 (Dublin, 1803), and eventually arrived in Paris (9 October 1802). MacNeven, Emmet and O'Connor availed themselves of their freedom to publish Memoirs of the Irish union (London, 1802), which they said was a full version of a memoir they had given the Irish government three years before. Though mistrustful of Bonaparte, MacNeven wrote a proclamation in anticipation of another French invasion of Ireland (December 1803) and entered the French army as a captain in the Irish Legion (7 December). Frustration soon set in as his mistrust of Bonaparte grew and as fellow officers quarrelled. MacNeven acted as second to one, John Swiney (qv), in his duel with another, Thomas Corbett (qv), which ended in Corbett's death (20 September 1804). He had already (10 August) sought permission to resign his commission (Arch. de la Guerre, Xn 14). Out of the army, he moved to Bordeaux. Next year he followed his friend and United Irish associate Emmet to America, landing at New York on 4 July 1805.
MacNeven quickly resumed the practice of medicine and soon received the degree of MD from Columbia College (1806). One of the 13 censors of the College of Physicians and Surgeons of New York at its foundation (1807), he was professor of midwifery and diseases of women and children there (1808–10), and then of chemistry (1810–26), his special knowledge of which was probably acquired in Prague and Vienna. Like his uncle before him, he became an enthusiastic reformer of medical education, establishing the first chemical laboratory in New York and introducing laboratory instruction for his students. MacNeven was co-editor of the New York Medical and Philosophical Journal and Review (1812–23). His position enabled him to develop his interest in chemistry. He is best known as a chemist for his early recognition of the importance of the atomic theory, expounded in his Exposition of the atomic theory of chymistry (1819). It was followed by his edition of W. T. Brande's A manual of chemistry (1820), to which he added notes, and A tabular view of the modern nomenclature (1821), which reported the latest developments in chemical classification. He had first published a scientific work as a young man, his translation of Geiss's Essay on the construction and use of a mine auger (1788). A work by MacNeven which must have owed something to his military experience in France was The nature and functions of an army staff (1812). He was a member of the American Philosophical Society (1823); he was a member too of the Literary and Philosophical Society of New York, which met sometimes at 7 Park Place, Broadway, his residence until 1839.
MacNeven continued his interest in Irish affairs. In New York he published (probably in July 1807) a collection of documents relating to Irish politics in the 1790s, including memoirs by himself and Emmet, Pieces of Irish history. It quickly went into a second edition and was influential in shaping nineteenth-century Irish nationalist perceptions of the 1798 rebellion. One concern of his was the welfare of other Irish immigrants, for whom he set up, at his own expense, a labour bureau in Nassau St. (1816). With William Sampson (qv), Thomas O'Conor (qv) and other Irishmen he formed an association, the Friends of Ireland Society, to promote Catholic emancipation (August 1828). It elected MacNeven as its president and sent money to the Catholic Association in Ireland. Another Irish association of which MacNeven was president was the Emigrant Society, the purpose of which was to promote the welfare of Irish immigrants. His last public act was in 1837, when he addressed a meeting of New York Irish on St Patrick's day.
MacNeven seems to have been the father of a child born of an irregular liaison (1790). Not until he was 47 did he marry (15 June 1810). His wife was Jane Margaret Tom, widow of John Tom of New York, a merchant, and daughter of Samuel Riker of Long Island, a member of Congress; they had three sons and two daughters. An unmarried daughter, Jane Maryanne, supplied a lengthy memoir to Madden which is an important source for MacNeven's life. Mrs MacNeven had by her previous marriage a daughter who married a son of his friend Emmet. William James MacNeven died 12 July 1841 just outside New York at the house of his son-in-law Thomas Emmet, having earlier that day received the last rites of the catholic church from the bishop of New York, John Joseph Hughes (qv). He was buried at the Riker family burial-ground at Bowery Bay, Long Island. A large monument to him stands in St Paul's churchyard, Lower Manhattan.
According to his daughter, Jane Maryanne, the first language he spoke was Irish, in which he still conversed fluently in America; he spoke English, German and French equally well and was versed in the literature of these three languages. He studied Italian, Latin and probably Greek; whether he knew Czech has not been ascertained. While living in Ireland MacNeven was a Freemason, a member of lodge no. 792. He was a political moderate. When touring Switzerland he told a retired Swiss army officer that at first he wished only for catholics to receive the benefits of the British constitution. Under detention in Ireland he had told the lords’ secret committee that he favoured a French invasion only to prevent bloodshed. In France he told an official that the United Irish envisaged for Ireland a government and parliament on the American model and a federal connexion with England. ‘My views for Ireland’, he told R. R. Madden (qv) in America in 1839, ‘are now limited to a domestic legislature for the business of the country, not extending to foreign affairs, continuing to be part of the English monarchy, subject to the king of England, no church establishment, no tithes’ (United Irishmen, 2nd ed., iii (1860), 242).