NICHOLSON, WILLIAM (1753-1815), a writer on natural philosophy, was born in London in 1753, and after leaving school made two voyages as midshipman in the East India service. He subsequently entered an attorney's office, but, having become acquainted, in 1775, with Wedgwood, he resided for some years at Amsterdam as agent for the sale of pottery. On his return to England he was induced by Holcroft to devote himself to the composition of light literature for periodicals, assisting that writer also with some of his plays and novels. Such work was little in accordance, however, with his scientific tastes, and he employed himself on the preparation of An Introduction to Natural Philosophy, which was published in 1781, and was at once successful. A translation of Voltaire's Elements of the Newtonian Philosophy soon followed, and he now entirely devoted himself to scientific pursuits and philosophical journalism. In 1784 he was appointed secretary to the general chamber of manufacturers of Great Britain, and he was also connected with the society for the encouragement of naval architecture, established in 1791. Besides his literary labours, he bestowed much attention upon the construction of various machines for comb-cutting, file-making, cylinder printing, &c.; he also invented an aerometer. In 1800 he commenced in London a course of public lectures on natural philosophy and chemistry, and about this period he made the discovery of the decomposition of water by the agency of galvanism, which was said to be the foundation of Sir Humphrey Davy's discoveries in the decomposition of the alkalins. In 1797 the Journal of Natural Philosophy, Chemistry, and the Arts, generally known as Nicholson's Journal, the earliest work of the kind in Great Britain, was begun ; it was carried on till 1814. During the later years of his life Nicholson's attention was chiefly directed to engineering works at Portsmouth, at Gosport, and in Southwark ; these with his other employments placed him in an affluent position, which, however, from domestic and other causes, he was unable to maintain. He died in poverty in 1815.

- A memoir was written by his son long after his death, but it never was published. Besides considerable contributions to the Philosophical Transactions, Nicholson wrote translations of Fourcroy's Chemistry (1787) and Chaptal's Chemistry (1788), First Principles of Chemistry (1788), and a Chemical Dictionary; he also edited the British Encyclopxelia, or Dictionary of Arts and Sciences, 6 vols. 8vo, London, 1809.