By no means was the task an easy one, as will presently be shown.  It was a work that would have to be carried on in the very teeth of jealous Nature.  Tom and Harry were fully aware of the great difficulties that lay before them.  What they did not know was that they would presently have to contend, also, with forces set loose by wicked human minds.  What started these untoward forces in operation, and how the forces worked out, will soon be seen.

Captain of a queer crew was Tom Reade, and Harry was his lieutenant.  Of the laborers, seven hundred in number, some four hundred were negroes; there were also two hundred Italians and about a hundred Portuguese.  Many, of each race, were skilled masons; others were but unskilled laborers.  There were six foremen, all Americans, and a superintendent, also American.  There were a few more Americans and two or three Scotchmen, employed as stationary engineers and in similar lines of work.

A touch of the old Arizona trouble had invaded the camp.  There had recently been a pay-day, and gamblers had descended upon the camp of tents and shanties.  Once more Reade had driven off the gamblers, though this time with less trouble than in Arizona.  At Blixton, Tom had merely sent for the four peace officers in the town of Blixton, and had had the gamblers warned out of camp.  They had gone, but there had been wrathful mutterings among many of the workmen.

The camp was a half mile back from the water’s edge, on a low hillside.  Here the men of the outfit were settled.  There had been mutinous mutterings among some of the men, but so far there had been no open revolt.

Tom, however, who had had considerable experience in such matters, looked for some form of trouble before the smouldering excitement quieted.  So did Harry.

On this dark night Tom had proposed that he and his chum take a stroll down to the shore front to see whether all were well there.  Soon after leaving camp behind, the young engineers had started on a jog-trot.  Just before they reached the water’s edge the wind had borne to their ears the faint report of what must have been an explosion out over the waters of the gulf.

“Trouble!” Tom whispered in his chum’s ear.  “Most likely some of the rascals that we drove out of camp have been trying to set back our work with dynamite.  If they have done so we’ll teach ’em a lesson if we can catch them!”

So the young engineers had started out over their narrow retaining wall.  We have seen how they had walked most of the distance when Harry had had his sudden warning of the hostile arm uplifted over his head.

“What could it have been?” demanded Tom in a low voice, as he continued to cast the light from his flash lamp out over the waters on either side of the wall.

“It must have been my nervous imagination,” admitted Harry.  “Whew!  But it did seem mighty real for the moment.”