of Abyssinian snow “that reaches to the knees.” This is, I believe, the earliest mention in antiquity of snow within the tropics (Asie Centrale, T. iii. p. 235); as the Paropanisus is 12° of latitude north of the northern limit of the torrid zone. Zimmermann’s map of the countries about the Upper Nile shews the dividing line which determines the basin of the Great River, and separates it on the south-east from the domain of the rivers which flow into the Indian Ocean;--that is to say, from the Doara, which enters the sea north of Magadoxo; from the Teb, which has its embouchure on the Amber coast, near Ogda; and from the Goschop, whose abundant stream is formed by the confluence of the Gibu and the Zebi, and which he distinguishes from the Godjeb, rendered celebrated since 1839 by Antoine d’Abbadie, the missionary Krapf, and Beke. These results of the travels of Beke, Krapf, Isenberg, Russegger, Rüppell, Abbadie, and Werne, brought together and shewn in the most comprehensive and convenient manner by Zimmermann, were hailed by me on their appearance in 1843 with the most lively joy, as expressed in a letter to Carl Ritter. “If,” I wrote to him, “a life prolonged to an advanced period brings with it several inconveniences to the individual, and perhaps some even to those who live with him, there is a compensation in the delight of being able to compare older states of knowledge with that which now exists, and to see great advances in knowledge grow and develope themselves under our eyes in departments where all had long slumbered in inactivity, with the exception, perhaps, of attempts by hypercriticism to render previous acquisitions doubtful. This enjoyment has from time to time fallen to our share, yours and mine, in our geographical studies, and this particularly in reference to those very parts of the world which formerly could only be treated of with timid hesitating uncertainty. The conformation of a continent depends in its leading traits on several plastic relations which are usually among the latest to be discovered and unravelled. A new and excellent work of our friend Carl Zimmermann, on the upper country of the Nile and the eastern parts of central Africa, has again brought these considerations very vividly before me. His new map shews in the clearest manner to the eye, by means of a particular method of shading, what is still unknown, and what, by the courage and perseverance of travellers of all nations,--among whom our own countrymen happily hold an important place,--has been already disclosed to us. It is a valuable service, and one which opens the way for farther advances and more comprehensive inferences, when persons, thoroughly acquainted with the existing, often widely scattered, materials,--men who do not merely draw and compile, but compare, select, and, wherever it is possible, check and control the routes of travellers by astronomical determinations of position,--undertake to represent graphically the