The karroo was reached while still it was lovely in its verdure. Gnus, with their pointed hoofs, caamas, elks, chamois, and gazelles abounded. Sir John could not resist the temptation to obtain two days' leave from the Colonel, which he devoted with all his energy to his favourite pastime. Under the guidance of the bushman, while Emery accompanied as an amateur, he obtained many a success to inscribe in his journal, and many a trophy to carry back to his Highland home. His hand, skilful with the delicate instruments of the survey, was at home still more on his gun; and his eye, keen to discern the remotest of stars, was quick to detect the merest movement of a gazelle. It was ever with something of self-denial that he laid aside the character of the hunter to resume the duties of the astronomer. The bushman's uneasiness was ere long renewed. On the second day of Sir John's interval of recreation, Mokoum had espied, nearly two miles to the right, a herd of about twenty of the species of antelope known as the oryx. He told Sir John at once, and advised him to take advantage of the fortune that awaited him, adding that the oryx was extremely difficult to capture, and could outstrip the fleetest horse, and that Cumming himself had not brought down more than four. This was more than enough to arouse the Englishman. He chose his best gun, his best horse, and his best dogs, and, in his impatience preceding the bushman, he turned towards the copse bordering the plain where the antelopes had been seen. In an hour they reined in their horses, and Mokoum, concealed by a grove of sycamores, pointed out to his companion the herd grazing several hundred paces to leeward. He remarked that one oryx kept apart. "He is a sentinel," he said, "and doubtless cunning enough. At the slightest danger, he will give his signal, and the whole troop will make their escape. We must fire from a long distance, and hit at the first shot." Sir John nodded in reply, and sought for a favourable position. The oryxes continued quietly grazing. The sentinel, as though the breeze had brought suspicions of danger, often raised his head, and looked warily around. But he was too far away for the hunters to fire at him with success, and to chase the herd over the plain was out of the question. The only hope of a lucky issue was that the herd might approach the copse. Fortune seemed propitious. Gradually following the lead of the sentinel male, the herd drew near the wood, their instinct, perchance, making them aware that it was safer than the plain. When their direction was seen, the bushman asked his companion to dismount. The horses were tied to a sycamore, and their heads covered to secure them from taking alarm. [Illustration: The Hunters glided through the Creepers and Brushwood.]