The two men, after gazing out to sea as if expecting to sight a vessel on the horizon, picked up the box and came on again.  Every step brought them nearer Alec, who of course had been told to allow all strangers to pass unchallenged—–­until to-morrow.

“Hark!” said one of the men, listening.  “That’s Rover barking!”

“He barks at nothing!” declared the other.  “Eet is a fool dawg, zat Rover!  I know heem, yes.”

“You haven’t as much sense as that ‘fool dawg,’ Max!” retorted the first speaker, who was none other than the swarthy ruffian, Harry Mole.  “Somethin’s going on over there at the settlement or the dog wouldn’t bark.  Come on, hurry; Branks may need us.”

So saying, he and his companion passed by, and Alec, who had heard every word, breathed a sigh of relief.  He wished the two men were not going in the same direction Dave and Billy had taken; but he felt sure that the latter could give a good account of themselves if discovered in hiding.

“But that would upset the whole scheme,” he reflected.  “Perhaps I’d better sneak around, ahead of those two rascals, and warn Dave and Billy to lie low?  Or shall I—–­no, I’ve been stationed here, and it’s up to me to stick to this post.”

As he watched the two men stumbling on over the uneven ground, he wondered with a little thrill of apprehension whether they would run across any of the other pickets, or even meet Billy and Dave returning from their quest.

However, no such undesired event came to pass, and the two smugglers finally disappeared behind a row of trees covered with vines.

After that, the watchful young pickets waited in silence, with only a low-spoken word now and then as they paced back and forth under cover to emphasize the stillness.  An hour passed,—–­another hour,—–­the sun began its slow descent into the broad bosom of the ocean.  Long before this, the Arrow had slipped away a little farther up along the coast, so that she would be out of sight behind one of the numerous islands in case the Esperanza drew near Durgan’s cove.

Once the dog’s barking sounded louder, and nearer, but after a minute or two it ceased, and silence reigned over all.

“What’s become of Dave and Billy?” wondered Chester.

The same question was troubling the minds of Roy Norton and Mark Anderson, in their respective station-points; but there seemed to be no answer to it at present.

Twilight crept upon them apace, then deepened into the shadows of night.  As they had arranged, they left their posts and assembled at the place chosen for their landing.  After hours of more-or-less solitary watching, it seemed good to be together in council, to eat their simple supper, and to compare notes.

In the midst of their evening meal, the faint purring of a motorboat’s engine reached their ears, and after a few minutes a boat with two figures in it was seen approaching them, gliding almost noiselessly along one of the waterways.  The occupants of the boat were Billy Worth and Dave.  Reaching the place, they stopped the engine, ran the boat’s nose into the soft bank, and sprang ashore.