A scarce and important 1809 Henry Salt nautical chart or maritime map Howakil Bay (Houakel), Eritrea. Howakil Bay is a large bite in the coast of Eritrea. It is a maze of small islands, reefs, and shoals that even in the early 20th were imperfectly mapped. In the periploi of antiquity Howakil Bay was known as Opsian Bay. Salt came to this bay to search out the opsian stone, most likely a form of obsidian, for which the bay was famous in antiquity. Near the village of Arena, identified on the western shore of this map, Salt collected several opsian shards which were later proven to be obsidian. This map was drawn by Henry Salt and Captain Thomas Weatherhead. It is dedicated to William Vincent, a scholar of antiquities who translated The Periplus of the Erythrean Sea, and whose work guided Salt as he explored the Red Sea. Without having ever visited the region, it was Vincent who correctly identified Howakil Bay as the Opsian Bay of antiquity. The present example was prepared to illustrate the 1816 French edition of Salt's Voyage to Abyssinia.