When the time came, however, the vizier’s promise was represented by two horsemen only. With them Dr. Barth started on his excursion, taking a north-east direction. The broad grassy plain seemed to roll away to an immeasurable distance, unrelieved by tree or shrub; not a living creature was visible, and the hot rays of the sun fell all around like burning arrows. After about half an hour’s ride, he reached swampy ground, through which he and his companions forced their horses, often up to the saddle. Thus they arrived on the margin of a fine open sheet of water, fringed thickly with papyrus and tall reed, from ten to fourteen feet high, among which wound and interwound the garlands of a yellow-flowered climbing plant, called “boibuje.” Turning to the north, and still pushing onward through deep water and grass, he made a small creek called Dímbebú, and caught sight of a couple of small flat boats, each about twelve feet long, and manned by a couple of men, who, on descrying the stranger, pulled off from the shore. They were Búdduma, or Yédiná, the pirates of the Tchad, in search of human prey; and Dr. Barth hastened to warn of their presence some villagers who had come to cut reeds for the roofs of their huts, and evidently had not caught sight of their enemies. He then continued his march. The sun’s heat was intense, but a fresh cooling breeze blowing from the lagoon rendered it endurable. Large herds of kelára, a peculiar kind of antelope, started up as he advanced, bounding swiftly over the rushes, and sometimes swimming on the silent waters. They are like the roe in shape and size, with their under parts white as snow. At another creek, which the lake pirates sometimes use as a harbour, river-horses abounded, and the air echoed with their snorting. This was the easternmost period of Dr. Barth’s ride; turning then a little west from north, he and his escort marched over drier pasture-grounds, and, in about three miles, struck a deeply indented and well-sheltered creek, called Ngómaíen. Here the curiosity of the traveller was rewarded by the sight of eleven boats of the Yédiná. Each was about twenty feet long, tolerably broad, with a low waist, and a high pointed prow. They are made of the narrow planks of the fógo-tree, fastened together with ropes from the dúm-palm, the holes being stopped with bast.