"Jet propulsion, Dirac hole,

Trochilminthes, Musterole,

Plenum, bolide, Ding an sich,

Shoot the savvy to me, Great White Which!"

The tune was one more commonly associated with Pepsi-Cola. After a moment the boy's mouth opened, and, licking the remains of the lollipop from its corners, he said clearly, "Two hundred. Night-prowlers."

"Is that all?" Hugh said, not much surprised.

"That's quite enough. Well, maybe not quite enough, but it's about all I ever get."

"But what does it mean?"

"Why, simply this: that your Atavars are two hundred years apart from each other; and that they are night-prowlers."

"Two hundred years! And I have to find them?"