And then, the first thing he knew, he began to slide off.

"Whoa! whoa!" he shouted.

He grabbed a piece of the harness and tried to hold on, but at every step Prince took he slid farther.

"Whoa! whoa!" he shouted again.

Prince slowed up, but it was too late. He turned his head just in time to see Bobby tumble to the ground. Then he stopped stock still.

Down on the stones and the thistles Bobby fell.

This was bad enough, but then he rolled against Prince's hind foot, a little stunned by the fall.

Father saw Bobby fall and ran toward him, thinking as he ran, "Oh, what if Prince steps on Bobby or kicks him?"

And Father ran faster than he had ever run before.

But there Prince stood and kept his foot as still as still could be, until Father came and pulled Bobby away. Then Prince started on to the barn.