"I'm not sure it was a person," said Polychrome, looking more grave than usual. "It seems to me that I merely ran into some hard substance which barred my way. In order to make sure of this, let me try another place."

She ran back a way and then with much caution advanced in a different place, but when she reached a position on a line with the others she halted, her arms outstretched before her.

"I can feel something hard - something smooth as glass," she said, "but I'm sure it is not glass."

"Let me try," suggested Woot, getting up; but when he tried to go forward, he discovered the same barrier that Polychrome had encountered.

"No," he said, "it isn't glass. But what is it?"

"Air," replied a small voice beside him. "Solid air; that's all."

They all looked downward and found a sky-blue rabbit had stuck his head out of a burrow in the ground. The rabbit's eyes were a deeper blue than his fur, and the pretty creature seemed friendly and unafraid.

"Air!" exclaimed Woot, staring in astonishment into the rabbit's blue eyes; "whoever heard of air so solid that one cannot push it aside?"