Author: Roy, W.
Title: Experiments and observations made in Britain, in order to obtain a rule for measuring hights with the Barometer.
Description: London, The Royal Society, 1777. 4to (22.2 x 17.4 cm). 18 pp. (numbered 653-770); two folding plates showing barometers; thirteen folding tables and a map showing the plan of the triangles made use of for obtaining the geometrical distance and altitude of Snowdon and Moel Eilio with respect to the Sea at Carnarvon, August 1775. Disbound. = True first edition taken from the Philosophical Transactions for the year 1777 (not from the later, abridged edition). This paper was published as a separate book a year later. Major-General William Roy (1726-1790) ..."was a Scottish military engineer, surveyor, and antiquarian. He was an innovator who applied new scientific discoveries and newly emerging technologies to the accurate geodetic mapping of Great Britain. His masterpiece is usually referred to as Roy's Map of Scotland. It was Roy's advocacy and leadership that led to the creation of the Ordnance Survey in 1791, the year after his death. His technical work in the establishment of a surveying baseline won him the Copley Medal in 1785" (Wikipedia). This is his only contribution to the Philosophical Transactions. His principal aim was the correction of errors in the observations of Deluc, published in the Philosophical Transactions some years earlier. The barometer depicted on the first plate is Ramsden's portable barometer. Disbound, trimmed. Some spotting on a few of the tables, one table bound cut in two and in two sheets, a few leaves creased but still a good copy of a rare work.

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