CHAPTER XXXIII.
THE SECRET AT LAST.
Mysteries are always uncomfortable. As Jack proceeded with his narrative, Dick and Tom looked nervously about them. Even the boys' two elders looked grave. The presence of a man on the island was almost inexplicable. But Jack's story was so circumstantial that there was no room to suppose that he might be mistaken. Besides, he had the bit of canvas to show, the scrap that he had taken from the thornbush.
After dinner Tom and Dick resumed their work of unloading necessaries from the Wondership. Jack and the two elder members of the party discussed plans.
"You haven't found any trace of mineral-bearing rock yet, have you, professor?" asked Jack.
The professor shook his head.
"Not a speck of anything that even remotely corresponds with the black sand that Zeb brought East with him," said the man of science, dejectedly.
"It isn't possible that we have been fooled," said Zeb.
"Or landed on the wrong island," struck in Jack.
"It must be the right island," declared Zeb.
"How do you make that out?" asked Jack.
"Well, it's got every mark on it that the map gives, for one thing," said Zeb.
"That's so," agreed the professor, and then he added hopefully: "However, I haven't covered half the ground yet."
Tom and Dick came tramping back at that juncture. They carried some canned goods and Dick bore the rusty shovel that they had seen the day before sticking up in the black barren.
"It was sticky and moist out there," he said, "but I figured we could always use this shovel, so I went out and brought it along."
He flung himself down full length in the shade for it was hot and there was not a breath of wind to fan the canyon. The professor, who sat facing Dick, concentrated his attention for an instant on the soles of the youngster's boots. Then he leaped up with a yell that startled them.
"What is it? The wild man?" gasped Dick, looking round him in alarm.
"No, your boots, your boots; look at them!" cried the professor.
"Is there a snake on them?" cried Dick, preparing to jump up.
"Don't move! Don't move for your life!" fairly screamed the dumpy little geologist, springing forward. He fell on his knees at Dick's boots as if they had been sacred, and with trembling fingers flaked off, into his left palm, some black mud which stuck to them.
Then he stood erect, his face aglow with triumph and enthusiasm such as the man of science rarely permitted himself.
"Gentlemen," he said, with a flourish, "there is no reason to look further for the mineral-bearing ground."
"You have found it?" choked out Jack.
"Yes."
"Where?"
"On Dick Donovan's boots."
They looked at him as if they thought he had suddenly gone demented. Dick examined his boots carefully as if he expected to see money plastered all over them.
The professor extended his palm. In it lay the black earth he had scraped from Dick's boots. In it tiny particles glittered and gleamed like myriads of infinitesimal eyes.
"Z. 2. X.," said the professor in solemn tones, and he waved his hand down toward the black barren where the moist, unhealthy-looking bare patch lay quivering and sweltering in the sun. A kind of haze hung above it, like a very thin fog.
"There it is," he went on, "down there. Waiting to be extracted from that black earth. Look."
He shook the black earth from his palm. Where it had lain there was a red, irritated-looking patch. The professor showed it. It looked like a slight burn.
"Did that stuff do it?" asked Jack.
"Yes; and that's almost as definite a proof as an analysis, of its intense radio activity. You noticed that the sample that Zeb had was enclosed in a leaden tube. That was the reason. Such powerful stuff would inflict bad burns if not handled properly."
"So that was why you made us include asbestos gloves and foot coverings and black goggles in the outfit?" cried Tom, who had been much puzzled over the reason for that part of the equipment.
"That was why," said the professor, "and that also is the reason we brought along those lead containers. Z. 2. X. or its ally, radium, or in fact vanadium or any of the allied radio-active metals, would destroy any other sort of container."
"Let's go down now and start digging," suggested impulsive Dick.
"Don't venture out there till you are fully equipped for the job," said the professor. "Serious results might ensue. In the meantime, I am going to analyze this sample in order to be doubly sure."
Jack gave a deep sigh of relief. After all, it was not a dream. They had found the valuable earth. It was now only a question of transportation. His father's fortunes were saved. The radio-'phone would be rushed to perfection and placed on the market within a short time of their return home.
While Jack lay back and indulged in daydreams, the others watched the professor as he tested the black sand over a portable assaying furnace and made all sorts of experiments to determine its value and the proportion of the different precious metals contained in it.
There was a slight rustling in the bushes behind him. Jack, whose nerves had been rather on edge since the occurrences of the preceding night and that morning, faced round quickly.
The next instant he uttered a loud shout.
Peering out of the bushes was a hideous, hairy face, more like an ape's than a human being's. From it glowed two wild, piercing eyes, like those of a beast of prey.
As Jack shouted and the others started toward him, the face vanished like a flash.