WILLIAM, a native of Scotland, was educated at the University of Edinburgh, where he finished his studies with great reputation, and acquired a considerable knowledge of the Latin tongue. On the 22d of May 1734, he received a testimonial from the heads of the university, certifying that he was a fit person to teach humanity in any school or college whatsoever. In 1739 he published at Edinburgh an edition of Johnston's Psalms. In 1742, he was recommended by Mr Patrick Cumming and Mr Colin MacLaurin, the professors of church history and mathematics, to the mastership of the grammar school at Dundee, then vacant. Whether he succeeded in his application or not, is uncertain; but a few years afterwards we find him in London, contriving to ruin the reputation of Milton, by an attempt which ended in the destruction of his own. His reason for the attack probably sprung from the virulence of party-spirit, which triumphed over every principle of honour and honesty. He began, in 1747, to retail part of his design in the Gentleman's Magazine; and, finding that his forgeries were not detected, he was encouraged in 1751 to collect them, with additions, into a volume, entitled An Essay on Milton's Use and Imitation of the Moderns in his Paradise Lost, in 8vo. But the fidelity of his quotations had been doubted by several people; and the falsehood of them was soon afterwards demonstrated by Dr Douglas, in a pamphlet entitled Milton Vindicated from the Charge of Plagiarism brought against him by Lauder, and Lauder himself convicted of several Forgeries and gross Impositions on the Public, in a Letter humbly addressed to the Right Honourable the Earl of Bath, 1751, in 8vo. The appearance of this detection overwhelmed Lauder with confusion. He subscribed a confession, dictated by a learned friend, in which he ingenuously acknowledged his offence, which he professed to have been occasioned by the injury he had received from the disappointment of his expectations of profit from the publication of Johnston's Psalms. This misfortune he ascribed to a couplet in Mr Pope's Dunciad (book iv. ver. 3), and thence originated his rancour against Milton. But he afterwards imputed his conduct to other motives, abused the few friends who continued to countenance him, and, finding that his character was not to be retrieved, quitted the kingdom, and went to Barbadoes, where for some time he taught a school. His behaviour there, however, was mean and despicable. He passed the remainder of his life in universal contempt; and died unregretted by any one, some time about the year 1771.