But the other craft had increased its speed. It was a powerful boat and a high curl of foam now rose from its bows as it plunged through the waves in a rapid flight toward the mainland in the distance. The roar of the engine was borne to the boys’ ears on the breeze.
“We’re going to lose them,” muttered Frank. “They’re too far ahead of us, unless we want to cut in and meet them right near the land.”
“That will only make them suspicious.”
“Yes, I guess we’d better let them go.”
Still, he did not give up the attempt just then, opening the throttle so that the Sleuth was racing along at top speed. But the other boat had the advantage, and cut across their course with a quarter of a mile to spare. Joe gazed through the binoculars, striving to identify the two men.
“No use,” he remarked, at last. “The fellow at the wheel is turned away from us, and the other man is bending down in the boat so I can’t see his face.”
“Is it the same boat?”
“I can’t be positive. But I think so. It certainly looks very much like it.”
“I’m almost sure. Of course, there might be lots of other motorboats just like it—but I’ve got a hunch that it’s the same craft.”
“What would it be doing at Blacksnake Island? There’s no doubt that it came from there.”
“That’s for us to find out. We’ll let them go on to the mainland. Then we’ll circle back and go up the other side of the island.”
In a short time the other craft disappeared from view, entering a small cove some distance down the coast, and Frank turned their boat about and headed toward Blacksnake Island again. They approached it from the seaward side and drew in as close to the island as they dared. The rocky bluffs were lonely and forbidding, seeming to offer no available landing place.
“We’ll go right around it. If Chet and Biff are there we should be able to see their boat or a fire or some sign of them,” said Frank, half questioningly, to his brother.
“After seeing that other motorboat, I’m pretty sure we won’t see any sign of them at all. I’m pretty well satisfied that those men kidnapped them and brought them here. And if they did, you may be sure they’ll be well hidden.”
“We’ll circle the island anyway, and if we don’t see anything we’ll land and make a search of the place.”
But making a circuit of the island took longer than the boys expected. Blacksnake Island was bigger than it had first appeared. It was almost a mile in length, and correspondingly wide—a great, swampy tract of forbidding marsh at one end, rising to higher ground and desolate rocks at the other. On the swampy side there were sinister little creeks, dead bushes half inundated, logs floating about in the black water. Frank and Joe caught glimpses of triangular black heads forging slowly through the water here and there.
“The blacksnakes!” Frank exclaimed.
Once the motorboat passed within a few yards of one of these black reptiles. Fascinated, the boys watched the ugly black head that projected above the surface, and they could see the long, sinuous body writhing beneath the water as the snake swam toward the fetid marsh.
“There must be hundreds of them on that island.”
“They’re dangerous, too. I’ve read about them. A bite from one of them means your finish.”
There were fewer snakes on the rocky side of the island and, after they had made the circuit without seeing any sign of human life, the boys decided to make a landing.
“Seeing that motorboat leaving here makes me believe someone is around,” declared Frank. “I won’t be satisfied until I find out for sure.”
“We won’t stay here all night?”
“It all depends. If we’re satisfied that the island is deserted, we’ll leave; but if we think we haven’t searched thoroughly enough, we’ll stay and hunt around again tomorrow. It’ll take a few hours to give the place a thorough going-over.”
“How about the snakes? Won’t it be dangerous staying here all night?”
“Oh, we’ll find some place where they can’t get at us. If the worst comes to the worst we can anchor the boat and stay in it.”
This decided, after some search they discovered a small cove, well protected from the sea, that appeared to offer a good landing place. The cove had a narrow entrance between the rocks, but widened out into a small lagoon, with water deep enough to enable the boys to bring their boat up close to a wide shelf of rock. They anchored the Sleuth then clambered up onto the rock.
“Feels good to stand on solid footing again,” Joe commented.
“I’ll say it does. Well, let’s be starting. Which way shall we go? Is it to be north or south?”
“It doesn’t matter much. To start with, we’ll nose around among these rocks for a while.”
The sun blazed on the bare crags as the boys picked their way over the rocks and boulders. Away in the interior they could see the waving tops of trees in the steaming marsh, but for the time being they contented themselves with exploring the rocky end of the island. It was quite barren and it appeared that no human being had ever set foot upon the place.
“You can’t blame them, either,” said Frank, when Joe had remarked on this fact. “It’s certainly not a place where I’d care to build my happy home.”
After about an hour of desultory search they came upon something that proved conclusively that human beings had indeed been there before them—and not long previously, at that. Charred embers and a crude fireplace built of rocks in a little hollow told the boys that someone had preceded them.
“We’re on the track of something,” declared Frank, as he examined the remains of the fire. “This blaze was built here not long ago. Someone has camped here.” He circled the rock, which dipped toward
