Scotty placed the stone in the pouch and gripped it in his left hand, holding the stone in place with thumb and forefinger. He took throwing position, left hand holding the pouch slightly lower than shoulder height while his right held the strings in the center of his body just above his belt buckle. He released the pouch and put his solid weight into the throw. Rick's lips pursed in a silent whistle. The stone sang shrilly as it flew up, up, up and far out. Then the trajectory dropped off rapidly and it fell into the sea. "Bless Bess!" Rick exclaimed. "Three hundred yards if it was an inch!" Even Scotty looked a little surprised. "I'm going to quit while I'm ahead," he announced. Barbara Brant, a slim, pretty, blond girl a year Rick's junior, hailed them from the porch, then ran down and joined them. "Hi! What are you two doing?" "Scotty just won the rock-throwing championship of the East Coast," Rick told her. Barby looked surprised. "He did? I thought you were waiting for Dr. Gordon?" "We are, but we decided to try out Scotty's new sling while we were waiting." The boys, and in fact the entire scientific staff of Spindrift Island, had been in a state of excitement for the past few days because of a telegram received from Dr. John Gordon. Dr. Gordon had been on leave for some time, working on a special project at a rocket experimental station in the West. A few days before, Dr. Hartson Brant, Rick's father and head of the Spindrift Scientific Foundation, a world-famous research organization, had received word from Gordon that Rick and Scotty were needed for a special assignment. Gordon had not given any details in his wire. This morning Dr. Gordon had phoned that he had been delayed, but would arrive by Navy plane around noontime. Long before noon, Rick and Scotty had moved Rick's four-passenger Sky Wagon off the grassy runway that ran along the seaward side of the island, then settled down to the rock-throwing session. Barby said, "I'm pretty good with a slingshot. Let me try." Scotty handed her the sling. She looked at it dubiously. "What's this? It isn't a slingshot." "It's a sling," Rick explained. "Not a slingshot. You know--like David and Goliath." Barby looked her disbelief. "You mean David killed Goliath with two pieces of string and a piece of canvas?" "He probably used leather thongs and a leather pouch," Scotty said, "but the idea is the same." "Show her," Rick suggested. Scotty picked up another of the larger stones and let fly. It dropped short of the earlier throw, but the effect was enough to make Barby's blue eyes open wide. "Where did you get it?" she asked excitedly. "Made it. Steve Ames showed me how, and how to throw."