Dr. Gustav Nachtigal, one of the great African explorers, was born at Eichstadt, near Magdeburg, in Germany. He was despatched on a mission to Bornu by the King of Prussia. After years spent with great advantage to science in the Sahara, round Lake Chad, and on the Shari River, he passed from Wadai into the Nile basin in the country of Darfur, and added somewhat to our geographical knowledge of this little known part of the Nile basin. Nachtigal reached Khartum at the end of 1874. Another German was to contribute his share to the opening up of the Nile basin. Dr. Wilhelm Junker was born at Moscow in 1840 of German parents, and was educated in Germany. He started for Egypt in 1875 with the intention of going to Darfur, but he spent some time examining the Libyan Desert and the curious blocked outlet of the Nile in the Fayūm. After exploring the Atbara as far as Kasala and journeying thence across country to the Blue Nile, he travelled up the Sobat River to Nasr (a point at which all exploration of the Sobat stopped for many years), and then made his way to the White Nile and the Makarka (Nyam-nyam) country. His journeys through the Bahr-al-Ghazal province took him as far south as the Kibali or Welle River. After a visit to Europe with his collections and notes, he returned to the Welle and the Mangbettu country. He explored the Welle and its tributaries for some distance eastward and westward. Munza, the celebrated king of the Mangbettu, about whom Schweinfurth wrote so much, had been murdered by the Nubian slave-traders, and the country about the Upper Welle was much disordered. Junker reached the Nepoko River, which is an affluent of the Aruwimi. His journeys westward to the Welle River near its confluence with the Mbomu convinced him that this mysterious stream, the existence of which had first been reported by Miani and Potagos (a Greek trader), was after all the most northern affluent of the Congo, and not the Upper Shari. Junker’s journeys were now interrupted by the news of the Mahdi’s revolt. [Illustration: NUĒR VILLAGE, SOBAT RIVER.]