“The ghosts!” cried Bob.
“Yes, radium ghosts!” fairly shouted Professor Snodgrass. “I understand it now. I wonder I didn’t guess it the first time. The ghosts we saw before were vapors, caused by radium. It is the same now. Boys, we have at last found the radium treasure! We will get it in the morning!”
They were up at dawn, after an almost sleepless night. Bob pointed out the spot where he had rested, and digging there, under a thin layer of sod, was found the peculiar hornblende rock mixed with pitchblende, which contained the radium. It needed but a simple test to demonstrate this.
“And the peculiar thing about it is this,” said Professor Snodgrass. “Usually it takes tons of rock to produce even a grain of radium, but in this case there is almost pure radium in this sample. We must be careful of it, for, not only is it very valuable, but it may seriously harm us if left exposed.”
Accordingly the first sample was put in the lead receptacle prepared for it, and the work of digging the rock for more was begun.
But if our friends hoped to find an enormous fortune of radium on Snake Island they were disappointed. For, after they had dug a little distance down, the rock disappeared, and there was no more of it. Search as they did, there was only a comparatively small quantity. But that was of great value, sufficient to more than compensate them for the trip, for the radium, being almost pure, commanded an exceptionally high price.
“But there must be some where we first saw the strange ghosts,” suggested Bob. They went to the place, but found nothing. As there was a deep hollow, where before there had been none, they concluded that the flood had washed the precious radium away.
“But we have enough to satisfy almost anyone,” said Jerry, one evening a few nights later.
In the days following Bob’s unexpected discovery of the precious stuff they had searched diligently, but no more was located.
“I think we have all there is here,” was the professor’s opinion, and Mr. Bentwell agreed with him. There was no longer any use in remaining in that desolate place, and so they arose, and left behind Snake Island, and the rushing river cutting its way through the mighty chasm, a mile below the surface of the earth.