A superb large-scale map of the island of Jersey doubling as a sea chart. It was originally published by Robert Sayer and John Bennett in 1779 and is found in the very rare ‘Complete Channel Pilot’, whose first publication is believed to have been in 1781. Unlike most sea charts this contains significant topographical detail on the island. Its water courses, roads, churches, and Cantons are detailed. There is even a number in each Canton reflecting the number of houses within. This detail is derived from the map of Clement Lempriere (1683-1746) published by W. H. Toms in 1755. He was born at St. Helier in Jersey, the son of Thomas Lempriere who prepared the map of the island in 1694 for Philip Falle’s ‘Account of the Isle of Jersey’. Traditional rhumb lines are found along with numerous depth soundings to aid safe navigation. Safe anchorages around the island are also identified. Of note also are three lines of sight affording safe navigation into the port of St. Helier. Robert Sayer (1725?-94) was born in Sunderland to a lawyer, James Sayer, and his wife Thomasine. In 1747 his elder brother James married Mary Overton, the widow of prominent mapmaker Philip Overton and the proprietor of his shop following his death. Mary continued the business for roughly a year after her marriage and then, in 1748, it passed to Robert. He became a freeman of the Stationers’ Company later that year; his first advertisement as an independent publisher was released in December. In 1754 he married Dorothy Carlos, ‘an agreeable young lady with a handsome fortune’!It is not known exactly what, and when, he acquired the stock of Thomas Jefferys (1719-71). It could have been following his bankruptcy in 1766, or at his death in 1771. In 1773 Sayer published ‘A General Atlas’ containing a series of large-scale maps. In 1774 he joined in partnership with his apprentice John Bennett (fl.1774-83), who had been made free in that year. The understanding was that in four years Bennett would become a partner with a third share in the business. The agreement allowed Bennett to continue more with the print side of the business and the management on a day-to-day basis. It allowed Sayer to take on less work and focus on maps which was his area of expertise. Bennett showed symptoms of insanity in both 1781 and 1783 and was admitted into an asylum. In 1784 the partnership was dissolved. Sayer died in 1794, and his stock was taken over by the firm of Robert Laurie & James Whittle.This chart exists in five states. A second is dated 1786 whilst the third bears the imprint of Laurie and Whittle and is dated 1794. This is the fourth with date altered to 1796 and is the first with the additional lines of sight added. One later issue dated 1813 has been identified. Provenance: Jonathan Potter Ltd. (1998) Catalogue 15 item 30; Robinson (1962); Rodger (1972) 601 recording 1786 as the first edition; Sanderson (1971) NMM 416 no. 10; Shirley (2004) M.SAY-2a 19; Worms & Baynton-Williams (2011).