e of the Gulf of Mexico!" cried the young
engineer, vengefully, as he tried to straighten up.

A groan escaped him. His injured foot was paining him more than he had
expected.

"Ha, ha! Ho, ho!" harshly jeered this mysterious, evil creature. The
black man had halted as Harry prepared to throw, but he showed no sign of
hesitation. Though he stood still, he thrust his repulsive, leering face
forward, as though to offer that face as the best mark.

Harry found that he could not stand straight---the pain in his injured foot
was now too intense.

"Get back with you!" ordered Harry. "Get back if you don't want a heap
worse than you gave me."

"Ha, ha! Ho, ho!" came the sneering laugh. Then the stranger reached out
his hands as though to seize the youth.

"I guess I'll have to do it---though not because I really want to hurt
you!" muttered Harry ruefully.

"Ha, ha! Ho, ho!"

There could be no question that the unknown was merely playing with him.
Little as he liked to make the ugly throw Harry knew that he had to do it.
When Hazelton had anything to do he believed in doing it well. So, putting
all possible force into his throw, Harry let the rock fragment fly, and
this time he was sure that his enemy would not be able to dodge in time.

Nor did the black man make any seeming effort to dodge.

Bump! Squarely in the black face the rock landed. Harry heard the sound
and felt ill within himself. Yet the black man did not stagger. With a
contemptuous snort he kicked the fragment of rock into the water as it
landed at his feet.

"Ha, ha! Ho, ho!"

For the first time Harry Hazelton felt positively dismayed. He saw the
long, massive arms moving, looking like a powerful ape's arms. There could
be no doubt that the unknown was ready for a spring.

Harry did not retreat. Where could he run to? Only a few yards could he
go out towards the end of the wall. Then, if he wished to continue his
flight he could only take to the water.

Only a glance was needed at the bulky, powerful frame of the unknown to
make it appear certain that the latter could swim two rods to the young
engineer's one.

Harry decided instantly to stand his ground and to make the most valiant
fight possible on so slippery a footing as that presented by the top of
the retaining wall.

"Ha, ha! Ho, ho!"

It was as though the black unknown sought to terrify his intended victim
with his repetitions of that harsh, discordant laugh. Ha