From the slight experience I had gained in the journey to Berber, I felt convinced that success in my Nile expedition would be impossible without a knowledge of Arabic. My dragoman had me completely in his power, and I resolved to become independent of all interpreters as soon as possible. I therefore arranged a plan of exploration for the first year, to embrace the affluents to the Nile from the Abyssinian range of mountains, intending to follow up the Atbara river from its junction with the Nile in lat. 17 degrees 37 minutes (twenty miles south of Berber), and to examine all the Nile tributaries from the southeast as far as the Blue Nile, which river I hoped ultimately to descend to Khartoum. I imagined that twelve months would be sufficient to complete such an exploration, by which time I should have gained a sufficient knowledge of Arabic to enable me to start from Khartoum for my White Nile expedition. Accordingly I left Berber on the 11th June, 1861, and arrived at the Atbara junction with the Nile on the 13th. There is no portion of the Nile so great in its volume as that part situated at the Atbara junction. The river Atbara is about 450 yards in average width, and from twenty-five to thirty feet deep during the rainy season. It brings down the entire drainage of Eastern Abyssinia, receiving as affluents into its main stream the great rivers Taccazy (or Settite), in addition to the Salaam and Angrab. The junction of the Atbara in lat. 17 degrees 37 minutes N. is thus, in a direct line from Alexandria, about 840 geographical miles of latitude, and, including the westerly bend of the Nile, its bed will be about eleven hundred miles in length from the mouth of its last tributary, the Atbara, until it meets the sea. Thus, eleven hundred miles of absorption and evaporation through sandy deserts and the delta must be sustained by the river between the Atbara junction and the Mediterranean: accordingly there is an immense loss of water; and the grandest volume of the Nile must be just below the Atbara junction. It is not my intention in the present work to enter into the details of my first year's exploration on the Abyssinian frontier; that being so extensive and so completely isolated from the grand White Nile expedition, that an amalgamation of the two would create confusion. I shall therefore reserve the exploration of the Abyssinian tributaries for a future publication, and confine my present description of the Abyssinian rivers to a general outline of the Atbara and Blue Nile, showing the origin of their floods and their effect upon the inundations in Lower Egypt.