Campbell says that by his death Covent Garden lost its best actor, and the British stage one of its brightest ornaments. Boaden, also Mrs. Siddons's biographer, calls Henderson ‘a man of great genius, and possessing the most versatile powers that I ever witnessed.’ He also said that the power of Henderson as an actor was analytic. He was not content with the mere light of common measure: he showed it you through a prism, and reflected all the delicate and mingling hues that enter into the composition of any ray of character. Kemble asked Mrs. Inchbald by letter concerning Henderson's Sir Giles Overreach, desiring to know what kind of hat, wig, cravat, &c., he wore, and saying, ‘I shall be uneasy if I have not an idea of his dress, even to the shape of his buckles and what rings he wears.’ Dugald Stewart, who heard him repeat a portion of a newspaper he had once read, declared his memory the most astonishing he had known. Henderson's letters display more information than was then general. His few poems have little merit. With Thomas Sheridan [q. v.] he wrote and signed ‘Sheridan's and Henderson's Practical Method of Reading and Writing English Poetry … a Necessary Introduction to Dr. Enfield's “Speaker,”’ London, 1796, 12mo, and probably earlier. Henderson had an interesting collection of books. He exhibited about 1767, at the Society of Arts and Sciences, a drawing which obtained a premium. Some of the etchings in Fournier's ‘Theory and Practice of Perspective,’ 4to, 1764, are by Henderson.
The portraits of Henderson as Macbeth, by Romney, and as Iago, by Stewart, with two other likenesses, are in the Garrick Club. The portrait of Henderson painted by his close friend Thomas Gainsborough [q. v.] is in London, in the possession of a descendant, by whom it is promised to a public collection.
[Books mentioned; A Genuine Narrative of the Life and Theatrical Transactions of Mr. John Henderson, commonly called the Bath Roscius, 3rd edition, London, 8vo, 1778, ascribed to Thomas Davies; Letters and Poems by the late Mr. John Henderson, with Anecdotes of his Life by John Ireland, Dublin, 1786; a Monody on the Death of Mr. John Henderson, by George Davies Harley [q. v.], Norwich, 1787, 4to; obituary notice of Henderson in various magazines for December 1785; Genest's Account of the English Stage; Davies's Dramatic Miscellanies, and Life of Garrick; Clark Russell's Representative Actors; Col. Chester's Westminster Abbey Registers; Reed's MS. Notitia Dramatica; Oulton's Hist. of the Theatres of London, 1796; Cumberland's Memoirs; Downes's Roscius Anglicanus; Recollections of O'Keeffe; Garrick Correspondence; Peake's Memoirs of the Colman Family; Bernhardt's Retrospections; Dibdin's Annals of the Edinburgh Stage.]
HENDERSON, JOHN (1757–1788), an eccentric student, was only son of Richard Henderson of Ballygarran, near Limerick. His father (from 1759 to 1771 one of the best itinerant preachers under John Wesley) made a living for some time as master of a boarding-school at Hanham, near Bristol, and finally kept a lunatic asylum in the same place. Wesley visited his house, and described him as ‘the best physician of lunatics in England’ (Journal, 25 Sept. 1789). John was born at Ballygarran on 27 March 1757, at a very early age came to England with his parents, and was sent to the school established by Wesley at Kingswood, near Bristol. According to his own confession he received only ‘a small school education,’ but was studious from childhood. His progress was so remarkable that at the age of eight he was able to teach Latin, and when only twelve years old taught both Greek and Latin at Trevecca College, then governed by John William Fletcher [q. v.] Two years later Fletcher was dismissed, and Henderson returned to his father's house, where he pursued his favourite studies and assisted in teaching. When aged 22 he accidentally, in a stage-coach, met Dean Tucker, who was so impressed by his conversation that he sent his father not only a letter urging that the young man should be sent to the university, but a gift of more than 150l. to be spent in his education. Henderson accordingly matriculated at Pembroke College, Oxford, on 6 April 1781, and occupied the rooms which had been tenanted by Dr. Johnson. He was an omnivorous student, and endowed with a marvellous memory. As a linguist he was skilled in Persian, Arabic, Hebrew, Greek, and Latin, and among European languages he knew Spanish, Italian, and German. Every branch of knowledge fascinated him. His temper was unruffled, and his benevolence led him, after he had acquired a knowledge of medicine, and an epidemic of fever was raging in Oxford, to practise gratuitously among its poor. At this crisis all his spare money was spent in drugs, and he sold his polyglot bible to purchase more. His conversation was bright and full of learning, and he had amusing mimetic gifts. Many friends sought his company. When Hannah More explored Pembroke College with Dr. Johnson in 1782, Henderson was one of the party. Johnson found him a firm tory and churchman. He is mentioned by Boswell as ‘celebrated for his wonderful acquirements in alchemy, judicial astrology, and other abstruse and curious
