g the mule to
follow; but this arrangement did not seem to suit the animal, for he
refused to budge a step from where he stood, nor could the man in the
rear push him along.

"Here, you!" the man called out to Derrick, "come back here and steer
him while I take his head. When he gets started, hang on to his tail
with all your might, and hold back all yer can."

So they changed places, and the mule was so greatly pleased at having
got his own way that he began to plunge down the stairs with great
rapidity. Derrick felt almost as though he were being rushed through
space on the tail of a comet, and shuddered to think of the broken limbs
and general destruction that must inevitably follow such reckless
travelling. The mule, however, seemed to know what he was about as well
as the man who led him, and took such good care of himself that Derrick
soon plucked up courage, and even began to enjoy the situation.

As he was thinking that they must be somewhere near the centre of the
earth, the mule gave an unusually violent plunge forward, and then
stopped so suddenly that poor Derrick found himself sprawling on the
animal's back, with both arms clasped tightly about his neck. With this
the mule began to caper and shake himself so violently that the boy was
forced to loose his hold and fall to the ground, amid roars of laughter
from a score of miners who witnessed the scene.

Greatly confused, Derrick scrambled to his feet, gave a reproachful
glance at the mule, which was calmly gazing at him with a wondering look
in his wide-open eyes, and turned to see in what sort of a place he had
been so unceremoniously landed. At the same moment Mr. Jones, dressed in
miner's costume, and looking as grimy as any of the others, stepped from
the laughing group and said,

"My boy, I congratulate you on being the first person who ever rode into
this mine on mule-back, I am glad you found the travelling-road so good.
Came on your own mule too. How did you know this was the bumping-mule
you were to drive?"

"I didn't know what sort of a mule he was until just as we got here and
he bumped me off his back," replied Derrick; "and I begin to think that
he knows more about driving than I do."

"Well, you have made a notable beginning," said the mine boss, "and I am
sure you two will get along capitally together. Harry Mule, this is
Derrick Sterling, who is to be your new driver, and I want you to behave
yourself with him." Then to Derrick he sa