15 part serial: CHAPTER TITLES: 1. The Sultan's Necklace; 2. The Bowstring; 3. The Air Peril; 4. Amid the Clouds; 5. Between Fire and Water; 6. The Abandoned Mine; 7. The False Pearl; 8. The Man Trap; 9. The Message on the Wire; 10. The Hold-Up; 11. Gems of Jeopardy; 12. Buried Alive; 13. Over the Falls; 14. The Tower of Death; 15. The Seventh Pearl.