An ACCOUNT Of The TRIGONOMETRICAL OPERATION, WHEREBY The DISTANCE BETWEEN The MERIDIANS Of The OBSERVATORIES Of GREENWICH And PARIS Has Been DETERMINED.
[London]: [1790]. 1st separate edition. 162 pp. Illustrated with 11 inserted copperplate engravings & 4 folding tables. Head- tailpieces. 4to: A^2 B - X^4. X4 blank. 11" x 8-7/8". Period pale green paper wrappers with paper title label to spine. Housed in a handsome quater-calf clamshell case. Lower corner lacking from front wrapper. Spine paper perished at ends. Usual bit of foxing & soiling. Withal, a VG copy in a Fine case. Item #30103
Roy was a Scottish military engineer, surveyor, and antiquarian, whose use of scientific advancements and accurate mathematical formulas paved the way for modern geodesic surveying. His tenure and his work are the dividing line between older, approximate mappings and newer, highly accurate ones in Britain. He is cited repeatedly in early nineteenth century mathematics textbooks for his use of spherical trigonometry in surveying. Early twentieth century technical books on modern surveying and geodesy include Roy's work as the historical starting point for the modern profession.
In 1783-84 he conducted observations to determine the relative positions of the French and English royal observatories. In 1784 he measured a base-line for that purpose between Hampton and Heathrow, the germ of all subsequent surveys of the United Kingdom, for which in 1785 the Royal Society awarded him the Copley medal. 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. [Wiki].
It is this latter which is herein documented.
Price: $2,500.00