A voyage to Abyssinia and travels into the interior of that country : executed under the orders of the British government, in the years 1809 and 1810 in which are included, an account of the Portuguese settlements on the east coast of Africa, visited in the course of the voyage ; a concise narrative of late events in Arabia Felix ; and some particulars respecting the aboriginal African tribes, extending from Mosambique to the borders of Egypt ; together with vocabularies of their respective languages /