comprehension.

There was something like a groan from Bull--a queer, animal sound that
made all three spectators shiver where they stood. For it showed that
the limit of that apparently inexhaustible strength had been reached
and that now the anguish of last effort was going into the work. They
saw the head bowed lower; the shoulders were now bunching and swelling
up on either side.

Then came a faint rending sound, like cloth slowly torn. It was
answered by something strangely like a snarl from the laborer.
Something jerked through his body as though a whip had been flicked
across his back. With a great rending and a loud snap the big stump
came up. A little shower of dirt spouted up with the parting of the
taproot. The trunk was flung high, but not out of the hands of Bull
Hunter. He whirled it around his head, laughing. There was a ring and
clearness in that laughter that they had never heard before. He dashed
the stump on the ground.

"It's out!" exclaimed Bull. "Look there!"

He strode upon them. As he straightened up he became huger than ever.
They shrank from him--from the veins which still bulged on his
forehead and from the sweat and pallor of that vast effort. The very
mustang winced from this mountain of a man who came with a long,
sweeping, springing stride. On his face was a strange joy as of the
explorer who tops the mountains and sees the beauty of the promised
land beneath him. He held out his hand.

"Lady, I got to thank you. You--taught me how!"