d slipped from his own
pony with a sharp, commanding "Whoa" to the little animal, which served
in a measure to reassure it.

The lad then sprang to the upright rock carrying the end of his rope
with him. He did not make the mistake of making the end fast to his own
body as he might have done in some circumstances. Instead he threw the
rope over the rock, taking one quick turn about it. He had no more than
taken that turn when the slack on the rope was suddenly taken up and the
rope was drawn taut.

There was no need to look around to see what had happened. Butler knew
well enough without looking. The pack mule had slipped over the edge and
was hanging there with the boy's lasso about its neck. The rope was
tough rawhide, and Tad felt sure it would hold. Still, that would not
save the mule, so he made fast and sprang to the other side of the
trail. The mule, he found, was dying a terrible death.

The freckle-faced Tad comprehended the situation in a single glance. He
knew now that it would not be possible to save the pack animal. Drawing
his revolver he placed the muzzle close to the head of the unfortunate
beast and pulled the trigger.

The report, in the walled-in pass, sounded like the discharge of a
cannon.

"N-n-n-now you've done it," chattered Stacy Brown.

"Tad, Tad! What have you done?" cried the Professor.

"I have put the poor thing out of its agony, that's all," answered
Butler. His face was pale and his eyes troubled.

"But you've killed him," protested Professor Zepplin.

"Didn't you see that he was choking to death, Professor? Don't you think
it was better to end his sufferings with a bullet rather than let him
slowly strangle?"

The Professor took off his sombrero, and, with an unsteady hand, wiped
the perspiration from his forehead.

"Too bad, too bad!" he muttered. "Yes, yes. You were right, Tad. You did
right. You thought more quickly and more clearly than I did. We had
better cut the rope and let him go. There is nothing else to be done, I
suppose."

"There is something else to be done, sir. There is something quite
important to be done."

"What do you mean?"

"The pack. Surely we are not going to send that pack crashing to the
bottom of the pass. We shall have to go all the way back for more
supplies if we do that, provided we ever find a place where we can turn
around."

"That is so. Still, lad, I am afraid it is hopeless. We never shall be
able to get the pack."

"I think it c