Dale did not bridle him, because he had not been broken to a bridle; and though it was harder for Bo to try to ride him bareback, there was less risk of her being hurt.

Bo had begun in all eagerness and enthusiasm, loving and petting the mustang, which she named "Pony." She had evidently anticipated an adventure, but her smiling, resolute face had denoted confidence.

Pony had stood fairly well to be mounted, and then had pitched and tossed until Bo had slid off or been upset or thrown.

After each fall Bo bounced up with less of a smile, and more of spirit, until now the Western passion to master a horse had suddenly leaped to life within her.

It was no longer fun, no more a daring circus trick to scare Helen and rouse Dale's admiration.
The issue now lay between Bo and the mustang.
Pony reared, snorting, tossing his head, and pawing with front feet.
"Pull him down!" yelled Dale.
Bo did not have much weight, but she had strength, an she hauled with all her might, finally bringing him down.
"Now hold hard an' take up rope an' get in to him," called Dale.