Engraved chart of Quseer Bay on the Red Sea coast of Egypt. North at 90 degrees. Variation shown.
When Napoleon invaded Egypt in June 1789, the Admiralty sent a squadron under Blankett to Suez to prevent the French from reaching India. He ordered a survey of anchorages and potential landing places for the British army at the head of the Red Sea, including Qusayr, and this was carried out by Dobbie in 1799. Sir Thomas Troubridge, who provided Dalrymple with Dobbie’s manuscript and to whom the printed chart is dedicated, was a Lord of the Admiralty. This is one of the earliest charts produced by Alexander Dalrymple for the Hydrographical Office.
However, Dalrymple’s chart does not represent the best information available at the time – see the manuscript chart DUC253:4/9. This was drawn by Austin Bissell in 1801. Comparing it to the printed chart suggests that Bissell’s chart was a redrawing of Dobbie’s survey. The two charts differ slightly: Bissell’s measurement of lat & long is more accurate, so it is likely that where the soundings do not agree, Bissell’s revisions were probably improvements.