Stacy looked intently, but the bright light hurt his eyes and he was forced to lower his eyelids a little. This made the circle seem brighter than before.
Now Professor Zepplin had discovered the peculiar thing.
"What is that—what does it mean, guide?" asked the scientist.
"That—that ring of light?" asked Parry.
"Yes."
"That is a halo, sir."
"A halo?" chorused the boys.
"Must be Chunky's then," suggested Walter.
"I agree with you," added Ned. "But I don't see what right he has to a halo."
"That particular halo is a very common thing in the Desert Maze," Tom Parry informed them. "It is caused by heat refraction, or something of the sort——"