THOMAS, D.D., a laborious and voluminous historical and biographical writer, born in London in 1705. His parents were Quakers; and his father was by trade a coffee-mill maker. By his unremitting diligence in his studies, though he had not the advantage of a university education, he soon became qualified to take holy orders in the Church of England. In 1728 he married the daughter of the Rev. Mr Cox, to whom he was curate; but in less than a year this lady died in childbirth. In 1732 he was recommended to the friendship and favour of the Lord Chancellor Hardwicke, then attorney-general, to whom, and to the succeeding Earl of Hardwicke, he was indebted for all his preferments. In 1732 he obtained the living of Ulting in Essex; and in 1734 was appointed one of the domestic chaplains to the unfortunate Earl of Kilmarnock, who was beheaded in 1746. He became a member of the Royal Society in February 1734-35, and of the Society of Antiquaries in December 1735; and was afterwards director of the latter, which office he held till his death. Previously, the Marischal College of Aberdeen had conferred on him the degree of master of arts. In 1743, through the interest of Lord Hardwicke, he was presented by the crown to the sinecure rectory of Landewy Welfrey, in Pembrokeshire; and in 1743-44 he was preferred to the rectory of Sidington in St Peter's, in the diocese of Gloucester; but he appears to have quitted this charge almost immediately. On the 24th of February 1743-44, he was appointed to the united rectories of St Michael Woodstreet and St Mary Staining; and in 1745-46 to the united rectories of St Margaret Patens and St Gabriel, Fenchurch Street. In January 1752 he was elected one of the secretaries of the Royal Society. In 1753 the Marischal College of Aberdeen created him doctor of divinity; and in that year the same degree was conferred on him by Archbishop Herring. He was one of the trustees of the British Museum, for which honour he was probably indebted to the Earl of Hardwicke, as he also was for his last preferment, the rectory of Depden in Essex, to which he was inducted in February 1761. In the latter part of his life he was chaplain to the Princess Amelia. In 1765 he resigned his office of secretary to the Royal Society. His death was caused by a fall from his horse, or perhaps by a fit of apoplexy, on the road between London and Hampstead, in the sixty-first year of his age. Dr Birch bequeathed his library of books and manuscripts, and all his pictures and prints not otherwise disposed of by his will, to the British Museum. He likewise left about £500, to be laid out in government securities, for the purpose of applying the interest to increase the salaries of the three assistant librarians.

His principal publications were, 1. The General Dictionary, Historical and Critical, including a new translation of Bayle, and interspersed with several thousand new lives, in ten volumes folio. 2. Dr Cudworth's Intellectual System, improved from the Latin edition of Mosheim; his Discourse on the true Notion of the Lord's Supper; and two Sermons, with an account of his Life and Writings, 2 vols. 4to, 1743. 3. The Life of the Honourable Robert Boyle, 1744, prefixed to an edition of that philosopher's works. 4. The Lives of Illustrious Persons of Great Britain, annexed to the engravings of Houbraken and Vertue, 1747-1752. 5. An Inquiry into the share which King Charles I. had in the Transactions of the Earl of Glamorgan, 1747, 8vo. 6. An edition of Spenser's Faery Queen, 1751, 3 vols. 4to, with prints from designs by... Kent. 7. The Miscellaneous Works of Sir Walter Raleigh, with his Life, 1751, 2 vols. Svo. 8. The Theological, Moral, Dramatic, and Poetical Works of Mrs Catherine Cockburn, with a Life, 1751, 2 vols. Svo. 9. The Life of Dr Tillotson, Archbishop of Canterbury, compiled chiefly from his original Papers and Letters; 1762, Svo. 10. Milton's Prose Works, 1753, 2 vols. 4to, with a Life. 11. Memoirs of the Reign of Queen Elizabeth, from the year 1581 till her death; from the original papers of his intimate friend Anthony Bacon, Esq., and other MSS.; 1754, 2 vols. 4to. 12. The History of the Royal Society of London, from its first rise; 1756 and 1757, 4 vols. 4to. 13. The Life of Henry Prince of Wales, eldest son of James I., compiled chiefly from his own papers and other MSS., 1760, Svo. His numerous communications to the Royal Society may be seen in the Philosophical Transactions.