Horsley undoubtedly received his early education at the grammar school of Newcastle, and completed it at the university of Edinburgh, where he was admitted to the degree of master of arts on the 29th of April 1701. For years afterwards nothing seems to be known of him, though some of them must have been given to the study of theology in connexion with the body of dissenters to which he belonged. There is some evidence tending to show that Horsley “was settled in Morpeth as a Presbyterian minister as early as 1709.” Mr Hodgson, however, thinks that up to 1721, at which time he was residing at Widdrington, “he had not received ordination, but preached as a licentiate.” Even if he was ordained then his stay at the latter place was probably prolonged beyond that date; for he communicated to the Philosophical Transactions notes on the rainfall there in the years 1722 and 1723. Mr Hinde also shows that during these years, in addition to his other duties, whatever their nature, “he certainly followed a secular employment as agent to the York Buildings Company, who had contracted to purchase and were then in possession of the Widdrington estates.” Soon after settling at Morpeth, Horsley began to supplement his professional income, probably slender, by opening a private school. The enterprise was successful. Respect for his character and abilities attracted pupils irrespective of religious connexion, one of them becoming afterwards Dean of Westminster. He likewise found time to give courses of lectures on mechanics and hydrostatics in Morpeth, Alnwick, and Newcastle; and it was doubtless in recognition of his scientific tastes and attainments that he was elected on the 23d April 1730 a Fellow of the Royal Society.

It is, however, in connexion with his archaeological researches that John Horsley is now so well and so honourably known, though strangely enough no place appears to have been hitherto found for his name in such works as the present. Among those who have investigated the traces left by the Romans of their presence in Britain he stands, and must ever stand, as in many respects the foremost. His great work, Britannia Romana, or the Roman Antiquities of Britain (London, 1732), one of the scarcest and most valuable of its class, contains the result of an amount of patient labour in this extensive field that in the case of a man in his position is truly marvellous. Nor was the acuteness of his intellectual powers less remarkable; for so accurately were his researches conducted and so solid was the judgment he brought to bear upon them that a century and a half of subsequent inquiry has invalidated only a few of the conclusions he came to.

Horsley died suddenly, of apoplexy, on the 12th of January 1732, his constitution having been in all likelihood prematurely worn out by the toil he had undergone in the composition of the Britannia Romana, then on the eve of publication. The following extract from the burial register of the parish of Morpeth gives the date of his interment: “173 j, Jan. 15, Mr John Horsley;” but the site of his grave is unknown. Besides the Britannia Romana, Horsley published two sermons and a hand-book to his lectures on mechanics, &c. He also projected a history of Northumberland and Durham, collections for which were found among his papers. By his wife, a daughter of the Rev. William Hamilton, D.D., minister of Cramond, afterwards professor of divinity in the university of Edinburgh, he had one son and two daughters.

HORSLEY, Samuel (1733-1806), a learned Anglican prelate, was born in London in 1733. Entering Trinity College, Cambridge, he became LL.B. in 1758 without graduating in arts, and in the following year succeeded his father in the living of Newington Butts in Surrey. Horsley was elected a Fellow of the Royal Society in 1767; but, in consequence of a difference with the president, he withdrew from it in 1784. He had been secretary since 1773. In 1768 he attended the eldest son of the earl of Aylesfbrd to Oxford as private tutor; and, after receiving through the earl and Bishop Lowth various minor preferments, which by dispensations he combined with his first living, he was installed in 1781 as archdeacon of St Albans. In 1774 the university of Oxford conferred on him the degree of LL.D. Whilst archdeacon, Horsley entered upon his famous controversy with the Socinian, Dr Priestley, who denied that the early Christians held the doctrine of the Trinity. In this controversy, conducted on both sides in the fiercest polemical spirit, Horsley showed the superior learning and ability. His aim was to lessen the influence which the prestige of Priestley’s name gave to his views, by proving from his writings the latter’s incompetence through ignorance to form an authoritative judgment on the disputed points. For the energy displayed in the contest Horsley was rewarded by Lord Chancellor Thurlow with a prebendal stall at Gloucester; and in 1788 the same patron procured his promotion to the episcopal see of St David’s. As a bishop, Horsley was energetic both in his diocese and in parliament. The efficient support which he afforded the Government in the latter place was acknowledged by his successive translations to Rochester in 1793, and to St Asaph in 1802. With the bishopric of Rochester he held the deanery of Westminster. He died at Brighton on October 4, 1806.

Besides the controversial Tracts, which appeared in 1783-84-86, and were republished in 1789 and 1812, Horsley’s more important works are :— Apollonii Pergoei Inclinationum Libri duo, 1770; Remarks on the Observations . . . for determining the acceleration of the Pendulum in Lat. 70° 51', 1774; Isaaci Newtoni Opera quee extant Omnia, with a commentary, 5 vols. 4to, 1779-84; On the Properties of the Greek and Latin Languages, 1796; Disquisitions on Isaiah xviii., 1796; Hosea, translated from the Hebrew, with Notes, 1801; Elementary Treatises on . . . . Mathematics, 1801; Euclidis Elementorum Libri priores XII. , 1802; Euclidis Datorum Liber, 1803; Virgil’s Two Seasons of Honey, &c., 1805; and papers in the Philosophical Transactions from 1767 to 1776. Since his death have appeared— Sermons, 1810-12; Speeches in Parliament, 1813; Book of Psalms, translated with Notes, 1815; Biblical Criticism, 1820; Collected Theological Works, 6 vols. 8vo, 1845. See Nichol’s Literary Anecdotes, vol. iv.

HORSLEY, William (1774-1858), an English musician of considerable reputation, was born November 15, 1774, and became in 1790 the pupil of Theodore Smith, an indifferent musician of the time, who, however, taught him sufficient to obtain the position of organist at Ely Chapel, Holborn. This post he resigned in 1798, to become organist at the Asylum for Female Orphans, as assistant to Dr Callcott, with whom he had long been on terms of personal and artistic intimacy, and whose eldest daughter he married. In 1802 he became his friend’s successor upon the latter’s resignation. Besides holding this appointment he became in 1812 organist of Belgrave Chapel, Halkin Street, and in 1837 of the Charter House. He died June 12, 1858. Horsley’s compositions are numerous, and include amongst other instrumental pieces three symphonies for full orchestra. Infinitely more important are his glees, of which he published five books, besides contributing many detached glees and part songs to various collections. Mr Barrett, in his lecture on “English glee and madrigal writers,” calls Horsley “one of the princes amongst glee writers,” and attributes to him “a fine and powerful dramatic aim and an elegant taste.” Horsley’s compositions are moreover distinguished by a remarkable purity of style, which sometimes verges on pedantry. His glees, “By Celia’s arbour,” “O nightingale,” “Now the storm begins to lower,” and others, are amongst the finest specimens of this peculiarly English class of compositions. Horsley’s son (Charles Edward), born in 1822, enjoyed a certain reputation as a musician. He studied in Germany under Hauptmann and Mendelssohn, and on his return to England composed several oratorios and other pieces, none of which had permanent success. In 1868 he emigrated to Australia. He died March 2, 1876, at New York.