The professor was silent a moment, and then he said quietly:
“Radium.”
“What!” cried Jerry. “Do you think someone has been here ahead of us, looking for the radium treasure?”
“I am sure of it,” said Uriah Snodgrass, “and what is more, I believe it was Mr. Bentwell.”
“Then where is he now?” demanded Bob.
“That I don’t know,” and the professor’s voice was solemn. “Probably he is dead. He must have been here on this lonely island nearly a year. How he lived in that time no one can tell. When he and his companions were wrecked there must have been some food saved. Or, he may have been able to trap, or kill, small animals that are on the island, or that were brought down by the floods. He may have caught fish. At any rate, we know that someone was alive here up to a month ago, for the date in the book tells us that. Where he went to, we can only guess.”
“The snakes,” suggested Ned in a low voice.
“Yes, the snakes may have killed him,” agreed the professor. “It is a sad ending to the life of a noted scholar, alone on this terrible island. I shall preserve this record he has left, for his family.”
“But where is the rest of it?” asked Jerry. “There are only a few pages here.”
“The others were destroyed, somehow,” replied Professor Snodgrass. “The same agency that made away with Mr. Bentwell may have destroyed the record of his uneventful search, or Noddy and his cronies, not understanding the value of the book, may have used pages of it to light a fire with, for on the hearth you can see where a fire has recently been kindled. It is too bad, for a scientific person, like Mr. Bentwell, probably made valuable observations of what took place in this wonderful canyon of the Colorado.”