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, only to reappear at the right of them. They were constantly getting nearer to it, however, so they kept their faces turned toward it as it flitted here and there to all points of the compass. Presently the Lion, who was leading the procession, halted abruptly and cried out: “Ouch!”

“What’s the matter?” asked Dorothy.

“Ouch—ouch!” repeated the Lion, and leaped backward so suddenly that Dorothy nearly tumbled from his back. At the same time Hank the Mule yelled “Ouch!” almost as loudly as the Lion had done, and he also pranced backward a few paces.

“It’s the thistles,” said Betsy. “They prick their legs.”

Hearing this, all looked down, and sure enough the ground was thick with thistles, which covered the plain from the point where they stood way up to the walls of the mysterious city. No pathways through them could be seen at all; here the soft grass ended and the growth of thistles began.

“They’re the prickliest thistles I ever felt,” grumbled the Lion. “My legs smart yet from their stings, though I jumped out of them as quick as I could.”

“Here is a new difficulty,” remarked the Wizard in a grieved tone. “The city has stopped hopping around, it is true; but how are we to get to it, over this mass of prickers?”

“They can’t hurt me,” said the thick-skinned Woozy, advancing fearlessly and trampling among the thistles.

“Nor me,” said the Wooden Sawhorse.

“But the Lion and the Mule cannot stand the prickers,” asserted Dorothy, “and we can’t leave them behind.”

“Must we all go back?” asked Trot.

“Course not!” replied Button-Bright scornfully. “Always, when there’s trouble, there’s a way out of it, if you can find it.”