From Wikipedia, the free encyclopedia

William Roy (1726 - July 1, 1790), was a Scottish surveyor, military draughtsman and antiquary, born in Carluke, South Lanarkshire.

At the age of 19 in 1746, when an assistant in the office of Colonel Watson, deputy quartermaster-general in North Britain, he began the survey of the mainland of Scotland, the results of which were embodied in what is known as the duke of Cumberland's map. In 1755 he obtained his commission in the 4th Kings Own Foot, and in 1759 gained his lieutenancy and went to serve in Germany in the Seven Years' War. In 1765 he appears as deputy quartermaster-general to the forces, surveyor-general of coasts and engineer-director of military surveys in Great Britain; in 1767 he became F.R.S., in 1781 major-general, in 1783 director of Royal Engineers.

Besides his campaigns and observations in Germany, his visits to Ireland (1766) and to Gibraltar (1768) were important. In 1783-84 he conducted observations for determining the relative positions of the French and English royal observatories. His measurement of a base-line for that purpose on Hounslow Heath in 1784, the germ of all subsequent surveys of the United Kingdom, gained him in 1785 the Copley medal of the Royal Society. Roy's measurements (not fully utilised until 1787, when the Paris and Greenwich observatories were properly connected) form the basis of the topographical survey of Middlesex, Surrey, Kent and Sussex. He was finishing an account of this work for the Phil. Trans. when he died.

These surveys were made for the most part using the new Ramsden theodolite which Roy had commissioned from Jesse Ramsden, and were the start of what is often called the Principal Triangulation of Great Britain

Roy's principal book-publication is the Military Antiquities of the Romans in Britain (1793). See also notices of him and contributions from him in the records of the War Office and the Royal Engineers, in the Transactions of the Royal Society of London, vols. lxvii., lxxv., lxxvii., lxxx., lxxxv., and in the Gentlemans Magazine, vols. lv., Ix. He is whimsically denounced by Jonathan Oldbuck of Monkbarns in Scotts Antiquary.

• This article incorporates text from the Encyclopædia Britannica Eleventh Edition, a publication now in the public domain.

see also Ordnance Survey, Ramsden theodolite, Principal Triangulation of Great Britain