and his extraordinary behaviour on the evening of that unfortunate nobleman's capture, led to a widespread but unfounded belief that it was he who betrayed him (Thomas Moore, Life of Lord E. Fitzgerald). On 22 May a reward of 300l. was offered for his apprehension, and on the evening of the following day he was captured, after a desperate resistance, in which ‘he was cut and scarred in upwards of fifty places, and was only saved by the number of his assailants,’ while reconnoitring Newgate, with a view to the rescue of Lord Edward Fitzgerald. When placed in the dock on 12 July he vehemently protested against the indignity of being loaded with fetters, which the turnkey excused on the ground of his extraordinary strength and ferocity. He declined to name counsel, ‘lest he might in any degree give his concurrence to the transactions of a court which he looked upon as a sanguinary tribunal for conviction and death, and not for trial.’
According to Roger O'Connor, who claimed to have special knowledge of the transaction, it was Neilson who, in order to save his own life, set on foot those negotiations which resulted in the famous compact of 29 July 1798 between government and the political prisoners, whereby the latter, in order to stay further executions, consented to disclose the plans and objects of the United Irish Society, and to submit to banishment to any country in amity with Great Britain. Taken by itself, Roger O'Connor's statement would carry little weight; for, as Secretary Marsden said, whatever the equality of his guilt might have been, he stood very low in the estimation of his companions; but it receives some confirmation from a passage in a letter from Henry Alexander to Pelham (Lecky, Hist. of England, viii. 196 n.) The truth is that, though satisfied beyond a doubt of Neilson's guilt and fully prepared to hang him for it, the government felt uncertain of securing a conviction, owing to the escape of McCormick, upon whom they depended for evidence of direct communication with Edward John Lewins [q. v.], and the unwillingness of their principal witness to come forward in open court, and consequently were fain to make a virtue of necessity, and include him in the compact (Cornwallis, Correspondence, ii. 370). He was examined before the committees of the lords and commons on 9 Aug. 1798, and wrote a letter strongly protesting against the statements contained in the preamble to the Act of Banishment (38 Geo. III, c. 78), which he was with difficulty restrained from publishing.
After ten months' imprisonment in Dublin he was on 19 March 1799, although confined to bed with a high fever, removed with the other prisoners on board ship, and transported to Fort George, in Scotland, where, after a tedious voyage, during the greater part of which he was quite delirious, he arrived on 14 April. During his detention at Fort George he was treated with great consideration by the governor. Like Tone, he was a hard drinker, but his weakness in this respect has probably been exaggerated. Certainly he was able, in order to procure the necessary means to obtain permission for his son, whose education he wished to superintend, to live with him, to deny himself the customary allowance of wine. On 21 July 1799 he wrote a remarkable letter to his wife, in approbation of the scheme of the union, which Madden (United Irishmen, 2nd ser. i. 247) improbably suggests did not represent his real opinion. On 4 July 1802 he was landed at Cuxhaven, and restored to liberty. But a rumour, originating probably with Roger O'Connor, having reached him reflecting on his conduct in regard to the compact of 29 July 1798, he formed the immediate resolution of revisiting Ireland. He succeeded in eluding the vigilance of the authorities—though the captain of the ship in which he sailed was arrested and imprisoned—and about the end of July 1802 landed at Drogheda, whence he made his way safely to Dublin. He lay concealed for some time in the house of Bernard Coile, at 16 Lurgan Street, and then, with the assistance of James Hope (1764–1846?) [q. v.], proceeded to Belfast, where he remained for three or four days, being visited in secret by his friends and relatives. He returned to Dublin, and was sheltered by Charles O'Hara at Irishtown for some weeks, till the American vessel in which his passage was taken sailed. He landed at New York apparently early in December 1802, and was contemplating starting an evening paper when he died suddenly of apoplexy on 29 Aug. 1803, at Poughkeepie, a small town on the Hudson, whither he had gone in the autumn to avoid the plague in New York. His remains were interred in the burial-place of a gentleman of his name, though no relation of his, and a small marble slab was subsequently erected to his memory.
An engraved portrait of Neilson, from a miniature by Byrne, is prefixed to the memoir of him by Madden (ib. 2nd ser. i. 73). He was a man of pleasing appearance, tall, well built, of extraordinary strength, boldness, and determination. In politics he aimed at the absolute separation of Ireland from England; but, like the Belfast leaders generally, he relied more on native exertions than on foreign intervention. His widow embarked in business