Sir John had not time to express his astonishment, when Mokoum, observing a movement in the distance, with all speed seized his gun and fired. He and Sir John hastened to the suspected spot. But the place was empty: they could perceive by the trampled grass that some one had just been there; but the Makololo was gone, and it was useless to think of pursuit across the prairie. The two hunters returned, much discomposed. The presence of a Makololo at the cromlech, together with his disguise, not unfrequently adopted by oryx hunters, showed that he had systematically followed the caravan. It was not without design that he was keeping watch upon the Europeans and their escort. The more they advanced to the north, the greater danger there would be of being attacked by the plunderers. Emery was inclined to banter Sir John on his return from his holiday without booty; but Sir John replied,-- "I hadn't a chance, William; the first oryx I hunted was dead before I shot at him." CHAPTER XVII. AN UNEXPECTED BLIGHT. After the oryx hunt the bushman had a long conversation with the Colonel. He felt sure, he said, that they were watched and followed, and that the only reason why they had not been attacked before was because the Makololos wished to get them farther north, where their hordes were larger. The question thus arose whether, in presence of this danger, they should retrace their steps; but they were reluctant to suffer that which nature had favoured to be interrupted by the attacks of a few African savages. The Colonel, aware of the importance of the question, asked the bushman to tell him all he knew about the Makololos. Mokoum explained that they were the most northerly branch of the great tribe of the Bechuanas. In 1850 Dr. Livingstone, during his first journey to the Zambesi, was received at Sesheki, the usual residence of Sebitouani, the chief of the Makololos. This native was a man of remarkable intelligence, and a formidable warrior. In 1824 he had menaced the Cape frontier, and, little by little, had gained an ascendency over the tribes of Central Africa, and had united them in a compact group. In the year before the arrival of the Anglo-Russian expedition the chief had died in Livingstone's arms, and his son Sekeleton succeeded him. At first Sekeleton was very friendly towards the Europeans who visited the Zambesi, and Dr. Livingstone had no complaint to make. But after the departure of the famous traveller, not only strangers but the neighbouring tribes were harassed by Sekeleton and his warriors. To these vexations succeeded pillage on a large scale, and the Makololos scoured the district between Lake Ngami and the Upper Zambesi. Consequently nothing was more dangerous than for a caravan to venture across this region without a considerable escort, especially when its progress had been previously known.