BANCROFT, Edward (1744-1821). An Essay on the Natural History of Guiana in South America. London: T. Becket and P.A. De Hondt, 1769.

8vo (210 x 127 mm). Engraved frontispiece showing a double-headed snake, 4pp. publisher's catalogue at end. Full contemporary calf, supralibros gilt on both covers (rebacked, corners rubbed). Provenance: The Society of Writers to the Signet (supralibros and shelf-label).

FIRST EDITION. Bancroft was a naturalist and chemist who had run away to sea from Massachusetts and settled in Guiana in 1763. He moved to England in 1767, studied at St. Bartholomew's Hospital, befriended Benjamin Franklin and Joseph Priestley, and was elected a Fellow of the Royal Society in 1773. “At the outbreak of war with the American colonies, Bancroft acted as a spy for Franklin. He was accused of conspiring with others in an attempt to burn Portsmouth Dockyard... Bancroft avoided arrest by escaping to France, where, in 1776, he turned King's evidence, and provided the British government with information... From December 1776 Bancroft received regular payments from the British for his spying activities, and the American government continued to pay him for similar services until 1783” (Oxford DNB).