"One o' these would be plenty to build," returned Jack. "Let's have a look at the ivory, Chuck." He pulled out his knife and ripped off the covering of the tusk Charlie had been pulling at. The ivory gleamed yellow and discolored in the sunlight, while a gasp of surprise went up from the Masai, as for the first time they realized what these things were. The gun-bearers gazed stolidly. [Illustration: One slash of the knife, and out trickled a little stream of yellow grains into the brown fist of the explorer.] "What's this?" Jack had held up the tusk, the point of which towered far above his head. As he lowered the hollow butt to the ground in triumph, Charlie sprang forward and picked up a little bag of skin that had been held inside the hollow end by a wooden plug, rotted away. The explorer leaped forward, whipping out his knife, and grabbed the little bag from Charlie's hand. One slash of the knife, and out trickled a little stream of yellow grains into the brown fist of the explorer. "Gold!" For a moment they all stood motionless, gazing at the little bag. Von Hofe's face expressed mild interest; that of Schoverling was aflame with passion; Charlie knew that his own eyes were gleaming and glittering, as were those of Jack. But almost instantly the General laughed and resumed control of himself. "We're acting like a lot of fools. Here, boys, rip open the rest of those tusks and see if there are more sacks." They fell to work with their knives, von Hofe joining in the work, and a few moments later a little heap of skin bags, each the size of a man's fist, was piled up. Each tusk had held one, and two or three yet retained the wooden plugs, which had to be dug out, so firmly were they fastened. Charlie stood at the edge of the group, oblivious to all else. Suddenly he felt the hand of his gun-bearer, Amir Ali, laid on his arm, and the Gurkha whispered in his ear. "Will the sahib come over here?" Wondering, the boy followed the Gurkha off to one side. The gun-bearer pointed to the mainland, toward the foot of the lake, and Charlie whipped out his glasses instantly. CHAPTER XVI SELIM SHOWS HIS TEETH No sooner had he obtained a focus than Charlie gave a cry of surprise. There, half a mile away still, were a dozen camels grouped together and covering the ground with huge strides. On their backs he could make out the white figures of men, and something flashed in the sunlight like a rifle-barrel. Despite his surprise, Charlie saw with a glance that the others had not heeded him, and smiled. Casing his glasses, he walked back to the group and stood beside Schoverling, who was examining some of the gold-dust from the opened bag. "I have a little surprise-party for you," he said quietly. They looked up at him, but Jack caught something in his voice. "You might be interested in knowing that Selim and his party are about half a mile away and coming up at full speed."