ls ever blind?" asked Trot.

"Always, in the daytime," said Button-Bright. "But Scraps can see with
her button eyes both day and night. Isn't it queer?"

"It's queer that buttons can see at all," answered Trot; "but--good
gracious! what's become of the city?"

"I was going to ask that myself," said Dorothy. "It's gone!"

The animals came to a sudden halt, for the city had really
disappeared--walls and all--and before them lay the clear, unbroken
sweep of the country.

"Dear me!" exclaimed the Wizard. "This is rather disagreeable. It is
annoying to travel almost to a place and then find it is not there."

"Where can it be, then?" asked Dorothy. "It cert'nly was there a minute
ago."

"I can hear the music yet," declared Button-Bright, and when they all
listened the strains of music could plainly be heard.

"Oh! there's the city--over at the left," called Scraps, and turning
their eyes they saw the walls and towers and fluttering banners far to
the left of them.

"We must have lost our way," suggested Dorothy.

"Nonsense," said the Lion. "I, and all the other animals, have been
tramping straight toward the city ever since we first saw it."

"Then how does it happen--"

"Never mind," interrupted the Wizard, "we are no farther from it than we
were before. It is in a different direction, that's all; so let us hurry
and get there before it again escapes us."

So on they went, directly toward the city, which seemed only a couple of
miles distant; but when they had traveled less than a mile it suddenly
disappeared again. Once more they paused, somewhat discouraged, but in a
moment the button eyes of Scraps again discovered the city, only this
time it was just behind them, in the direction from which they had come.

"Goodness gracious!" cried Dorothy. "There's surely something wrong with
that city. Do you s'pose it's on wheels, Wizard?"

"It may not be a city at all," he replied, looking toward it with a
speculative gaze.

"What _could_ it be, then?"

"Just an illusion."

"What's that?" asked Trot.

"Something you think you see and don't see."

"I can't believe that," said Button-Bright. "If we only saw it, we might
be mistaken, but if we can see it and hear it, too, it must be there."

"Where?" asked the Patchwork Girl.

"Somewhere near us," he insisted.

"We will have to go back, I suppose," said the Woozy, with a sigh.

So back they turned and headed for the walled city until it disappeared
again