# Dictionary of National Biography, 1885-1900/Henry, Thomas (1734-1816)

​HENRY, THOMAS (1734–1816), chemist, was born at Wrexham on 26 Oct. 1734, and educated at the grammar school there. His father had come to Wales from Antrim, and kept a boarding-school at Wrexham. On leaving school Thomas was apprenticed at Wrexham to an apothecary, on whose death he completed his term at Knutsford, Cheshire. When his apprenticeship terminated he became assistant to an apothecary named Malbon at Oxford. While there he attended anatomical lectures. Returning to Knutsford in 1759, he began business on his own account, and soon afterwards married Mary Kinsey of that town. He removed five years later to Manchester, and succeeded to the business of a surgeon-apothecary in St. Anne's Square.
He had already manifested a taste for chemistry, and now energetically devoted himself to that study. In 1771 he communicated to the Royal College of Physicians ‘An Improved Method of Preparing Magnesia Alba,’ which was published in their ‘Transactions’ (vol. ii.), and afterwards reprinted in 1773 with other essays, entitled ‘Experiments and Observations,’ &c. His process of preparing calcined magnesia was communicated to the Royal College of Physicians without any reservation; but at the suggestion of the president of the college and other leading medical men he took out a patent and prepared it for sale. It became a lucrative property.
He was admitted a fellow of the Royal Society in 1775, on the recommendation of Sir John Pringle and Dr. Priestley. Some years later he was elected a member of the American Philosophical Society at the instance of Dr. Franklin. About the same time he published a paper ‘On the Action of Lime and Marl as Manures,’ which was reprinted in Hunter's ‘Georgical Essays,’ 1803, ii. 47. In 1776 he translated some of Lavoisier's works (‘Essays, Physical and Chemical’), and in 1783 a further selection of the same writer's ‘Chemical Essays.’ He first observed that a certain amount of carbonic acid in the air is favourable to the growth of ​plants. In 1781 he issued ‘An Account of a Method of Preserving Water at Sea,’ in which he proposed the use of lime to prevent putrefaction.
On the organisation of the Manchester Literary and Philosophical Society in 1781 he was appointed one of its secretaries. He became its president in 1807, and retained the position during the rest of his life. Many papers were read by him before the society, and some are printed in its ‘Memoirs.’ These comprise essays on the ‘Advantages of Literature and Philosophy,’ ‘Ferments and Fermentation,’ ‘Observations on the Bills of Mortality of Manchester and Salford,’ ‘The Nature of Wool, Silk, and Cotton as objects of the Art of Dyeing,’ and a ‘Memoir of Dr. Charles White.’ In 1783 he published ‘Memoirs of Albert de Haller,’ and helped to establish in Manchester a College of Arts and Sciences, in connection with which he delivered several courses of lectures on chemistry. In these lectures he was assisted by his son, Thomas Henry, jun., a youth of promise, who died young. He also lectured on bleaching, dyeing, and calico-printing. Henry was clear-headed, ready, and practical. Although his special study was pursued amid the anxieties of business, he occasionally contributed to medical journals, and interested himself in the literature and politics of the day. He was an early member of one of the first societies for the abolition of the African slave trade. About middle life he left the church of England and joined the unitarians.
He died on 18 June 1816, aged 81, and was buried at the Cross Street Unitarian Chapel, Manchester. His son William is separately noticed. His portrait, by Joseph Allen, belongs to the Manchester Literary and Philosophical Society.
[William Henry's tribute to his father's memory, in Memoirs of Manchester Lit. and Phil. Soc., 2nd ser. iii. 204, reprinted, with funeral sermon by J. G. Robberds, 1819; R. Angus Smith's Centenary of Science in Manchester, 1883, p. 108; Royal Society's Cat. of Scientific Papers; Watt's Bibl. Brit.; communication from Dr. W. C. Henry.]
C. W. S.