"Say, Jack," exclaimed Charlie as they bent over the boar, "didn't it strike you queer that they'd run out that way? 'Most as if somethin' was after 'em." "Right," and Jack sprang to his feet. Looking closely, they could see the tops of the twenty-foot reeds along the river-bank shaking heavily and slowly, as if massive bodies were advancing. "Maybe it's a rhino, Chuck. He wouldn't bother us--hello! What's up?" A chorus of shrill yells from the Masai above startled them. Glancing up, they saw Schoverling and the gun-bearers catching up their weapons, while the natives were leading the cattle away from the wagon, the inspanning having already begun for the march. They saw Gholab Singh catch up the little rifle belonging to von Hofe. "Jumpin' sandhills!" began Charlie in wonder. "What on earth--" "Get up here!" roared the General at them. "Boys! Quick!" Without pausing to inquire further the boys jumped for the camp. A moment later they stood gazing around in amazement, inquiring what was wrong. For answer the explorer pointed to the river below. The boys whirled, then a single cry burst from their lips and they stood astounded, unable to believe their eyes. "Ach, himmel! Vot a sight!" broke from the doctor. There, bending down the tough reeds like grass, a mighty herd of buffalo was coming slowly forward, the first two or three just emerging into the clearing. All together, there must have been sixty or seventy of them--but what buffalo they were! Great, shaggy fellows, nearly a third larger than those the boys had seen and shot during the first part of the trip, they seemed like some part of a wild dream. It flashed through Charlie's mind that it must have been such buffalo as this that Mowbray had seen, or rather, that had scattered his Arabs. Slowly the great mass pushed forward, heads upturned. Plainly they had scented the camp, for they were down-wind, and intended to investigate. Both boys realized that they were in grave danger, as this became apparent. "Think they'll dare to charge us?" murmured Charlie, a little pale. "Can't tell," returned the explorer, staring. "Great Scott, what animals! No wonder Mowbray's men lit out for safety! If they come on, we're goners." That they plainly meant to come on was soon evident. The foremost paused to sniff and paw the body of the slain boar, and to gaze up at the waiting men, then those crowding behind shoved them onward. Two or three went on to one side, but the others began the ascent of the little hill without hesitation. "We'll have to stop them," said Schoverling, his face set. Charlie looked around to find Jack at his elbow, gun ready, black eyes glittering, and cheeks flushed darkly. Behind were grouped the Indian gun-bearers, fully recognizing the danger. The Masai, chattering but with arrow on the string, stood near the wagon.