 What clue did the water tanks and tubing give Jery?
So when the Chief of World Security told him that he had been selected as the answer to the Solar System's greatest mystery, Jery assumed that it was because of his mental agility. But when he got to Mars to find out why fifteen boys had vanished from a spaceship in mid-space, he found out that even his quick mind needed time to pierce the maze of out-of-this-world double-dealing. For Jery had become a walking bomb, and when he set himself off, it would be the end of the whole puzzle of THE SECRET MARTIANS—with Jery as the first to go! "All it gives is my description, governmental status, and address!"
 An idea of how and when the boys went missing - probably during the night
 An idea of how and when the boys went missing - probably during the night  An idea of how much water was used during the trip  An idea of how and when the boys went missing - probably via the tanks  An idea as to whether or not the other man was lying