The efforts of the boys were well timed. Everything went like clockwork, or so it afterward seemed. Two shadowy forms were discerned standing in the thicker darkness under the trees as the automobile arrived near the Southern edge of the quarry. The boys were within easy attacking distance from the place where the two men stood. Ernie whispered the word "Halt" loud enough for his companions to hear him. They gathered around their leader, who hurriedly spoke thus: