The district treated of in this volume constitutes the extreme south-east corner of Egypt, lying between the parallels of 22° and 25° of north latitude, and between the meridian of 34° E. and the Red Sea coast. It comprises an area of about 56,000 square kilometres, and includes some of the most mountainous and least accessible portions of the Khedive’s dominions. The district has been comparatively little visited by travellers, and the literature concerning it is not very extensive. Berenice (_Jh_)[1] was founded by Ptolemy II (285-247 B.C.), who named the town after his mother, as a station at one end of the road for transporting goods from the Red Sea to the Nile at Koptos (Quft). The emerald mines in the Zabara area were worked at least as early as Ptolemaic times, and gold mines in the south at a much earlier date. References to this part of Egypt occur in the writings of STRABO, DIODORUS SICULUS, and PLINY, as well as in PTOLEMY’s Geography and the ANTONINE ITINERARY. Both Strabo and Pliny state that in Berenice, as in Syene, the sun cast no shadow at the summer solstice from which they inferred the town to be on the tropic of Cancer, though in reality it lay in their day some twenty-five kilometres, and is now about 28′, or some fifty-two kilometres, north of the tropic, the difference being caused by the secular change in the obliquity of the ecliptic since the beginning of the Christian era. Ptolemy gives the latitude of Berenice as 23° 50′, which is only 5′ too low; the _Smaragdus mons_, or emerald mountain, he places in latitude 25°, which is about 15′ higher than the true position of Gebel Zabara (_Ec_). Diodorus gives a very clear description of the working of gold mines in the Eastern Desert in his day, by miserable convict labour. The road from Koptos to Berenice is mentioned, with lists of stations and water reservoirs and their distances from each other, both by Pliny and the writer of the Antonine Itinerary; and though Pliny gives fewer stations than the Itinerary, the two accounts agree very closely in estimating the total distance at about 258 Roman miles, which, so far as can be judged from a partial identification of the stations marking the route, is pretty correct. The island of Zeberged (_Ok_), on which occurs the green gem called peridot, is probably the _Topazos Insula_ of Diodorus, and the _Agathon_ of Ptolemy; but Diodorus gives its length as eighty stades (about twelve kilometres), which is three times greater than its present size, and Ptolemy’s latitude of 23½° is some 16′ too low. Ptolemy states that the coast was inhabited by the _Ichthyophages_, or fish-eaters, while the _Troglodytes_, or cave-dwellers, of Strabo, were probably the workers in the mines. The books of the Arab geographers, EDRISI and ABU EL FEDA, contain some references to the roads and mines of the Eastern Desert, but their descriptions are unimportant and contain frequent palpable errors.