In the first place, we must endow Africa with a great transcontinental line from west to east, destined to ensure rapid communication between the different French and British colonies bordering on the Sudan. I have proposed for this railway the name “Transsudanese” (_Comptes Rendus_ of the Academy of Sciences, vol. 169, p. 418. Sitting of 1 September 1919 (Gauthier Villars, Paris)); and its main lines, roughly indicated by the natural features of Africa, and following the 13th degree of north latitude, should include the following points:— (_a_) Dakar and Konakry, starting-points on the Atlantic Ocean; (_b_) Ouagadougou, Sokoto, Kano, Fort Lamy, Khartoum, crossing the French Sudan, British Nigeria, the French territory of the Chad, and the Anglo-Egyptian Sudan; (_c_) Port-Sudan and Djibouti, termini on the Red Sea. Secondly, along this “Transsudanese” would be formed junctions at the most suitable points, with local branch lines from the different French and British colonies that succeed one another along the Atlantic coast from the mouth of the Senegal to that of the Congo. Thirdly, this railway system would be connected with the Mediterranean ports—on the east by the Nile valley railway from Khartoum to Cairo; on the west by a French “Transsaharian,” starting from the great bend of the Niger and connecting with the railway systems of Tunis, Algeria, and Morocco, and at some future time with that of Europe by a tunnel under the Straits of Gibraltar, or simply by train-ferry. Among the many reasons urgently in favour of the construction of the Transsudanese, I will confine myself to stating what seems to me the most important and perhaps the least known, the question of labour. For it is generally agreed that the opening up of Tropical Africa cannot be undertaken without the large co-operation of black labour. Now, for long years to come four-fifths of that labour will have to be supplied by the Sudanese populations, much less wild and much less indolent than the great majority of the coast populations, and consequently better fitted to lend useful aid to European enterprises. This Sudanese population, which may be estimated at some fifteen millions at the lowest count, is spread over more than a million square miles (4000 miles from west to east from the Atlantic to the Red Sea, and 250 to 300 miles from north to south, between the 11th and the 15th degrees of north latitude). To recruit workmen scattered over such vast distances and convey them without loss of time to the points where European enterprises are ready to employ them, it is evident that an unbroken line of railway must pass through the total length of the inhabited zone—that is to say, of Sudanese Africa. And it is of supreme importance that this railway should not have to take into account the political frontiers of the various colonies passed through, and that its one concern should be to traverse the regions in which the population is densest.