that the monster's eyes seemed to flame, and
still nearer and nearer, with the great animal tossing its head, and
making believe to lower it and tear up the earth with one horn.

"If he don't run we must," thought Bart, at last, as Black Boy slowly
and cautiously took him up to within a yard of the shaggy beast, whose
bovine breath Bart could smell now as he tossed his head.

Then, all at once, the great fellow wheeled round and thundered down the
slope, while, as if enjoying the discomfiture, Black Boy made a bound,
cleared the ridge, and descended the other slope at full gallop close to
the bison's heels.

All Bart's fear went in the breeze that swept by him. He felt ready to
shout with excitement, for the valley before him seemed to be alive with
bison, all going along at a heavy lumbering gallop, with Joses and the
Indians in full pursuit, and all as much excited as he.

His instructions were to ride right in between two of the bison, single
out one of them, and to keep to him till he dropped; and Bart saw
nothing but the huge drove on ahead, with the monstrous bull whose
acquaintance he had made thundering on between him and the main body.

"I must keep to him," thought Bart; "and I will, till I have shot him
down."

"If I can," he added a few minutes later, as he kept on in the exciting
chase.

How long it lasted he could not tell, nor how far they went. All he
knew was that after a long ride the bull nearly reached the main body;
and once mingled with them, Bart felt that he must lose him.

But this did not prove to be the case, for Black Boy had had too good a
training with cattle-driving. He had been a bit astonished at the
shaggy hair about the bison's front, but it did not trouble him much;
and without being called upon by spur or blow, no sooner did the bison
plunge into the ranks of his fellows as they thundered on, than the
gallant little horse made three or four bounds, and rushed close up to
his haunch, touching him and the bison on his left, with the result that
both of the shaggy monsters edged off a little, giving way so that Bart
was carried right in between them, and, as Joses had suggested, there
was one moment when he could literally have kicked the animals on either
side of his little horse.

That only lasted for a moment, though; for both of the bison began to
edge away, with the result that the opening grew wider and wider, while,
remembering enough of his lesson, Bart kept close