ghed mischievously.
"But, Corbett, I believe that four bombs are even now attached to some
part of the retaining wall, ready to be set off.

"Great Scott!"

"They won't be set off, though," continued Reade. "I found the firing
magneto, and had a chance to cut the wires."

The foreman wanted to ask more questions, while the half dozen workmen
trudged along close at their heels, eager to hear every word. Tom,
however, suggested that they save their breath in the interest of speed,
until they had Mr. Sambo Ebony in safe custody.

"Here we come, Nicolas!" Tom called, as the party neared the spot where
captor and captive had been left.

There was no response.

"Nicolas!" Tom called again, with a start.

Still no answer.

"I don't like the look of that," Reade uttered. "Let's get there on the
sprint!"

Tom himself caught at one of the lanterns, leading the way. Neither the
negro nor the Mexican was where the young chief engineer had left them.

Feverishly, Tom began to search the ground, holding his lantern close.

"Hang the luck!" he quivered, pointing to fragments of cord on the sand.
"That negro simply burst his bonds---and now where is he? Where is
Nicolas, for that matter? I thought the little fellow, with his trick,
could easily take care of the big black."

But, though they spread out and searched, there was no sign of either the
negro or the little brown man.

"I can't understand what has happened," quivered Tom Reade, thinking more
of the staunch little Mexican than of the loss of the prisoner.

CHAPTER XVI

A TEST OF REAL NERVE

"What an idiot I was not to stop to consider that Sambo Ebony could snap
those cords!" groaned Tom, staring disconcertedly about him. "Yet, if
Nicolas were safe I wouldn't so much mind the escape of the black. I shall
see him again, and I shall know him wherever I see him."

"Let's look for the trail," proposed Foreman Corbett, holding one of the
lanterns close to the ground.

The trail, however, was easy neither to distinguish nor to follow.

"We may as well leave here and search farther," concluded the young
engineer. "Before we go, though, we'll get the magneto and take it with
us."

Then the procession turned toward the land end of the retaining wall.

"If Nicolas doesn't show up soon," Tom murmured to the foreman, "I shall
notify the Blixton police and offer a reward for news of him. That little
fellow is too faithful to be left to his fate."