"You have heard of the x-rays, no doubt; they are the actinic or ultra violet, which are above the visible light. These light vibrations are of such a character that they penetrate many substances. A curious effect of this was shown some time ago when a photograph was taken of the side of a vessel which had several coats of paint over the old name, and the photograph showed not only the new name, but also the old one beneath."
The time had now arrived when they must make preparations for the proposed voyage of discovery around the island. It was a momentous time for them. The boys could not help but look with longing eyes to the cave. Before they went it was felt something more should be learned about its mysteries.
The Professor was not at all backward in encouraging this feeling.
"Wouldn't it be a good thing to take such things out of the cave as we can make use of here, and during our trip?" said Harry.
"What things do you think we could utilize?"
"Probably the guns; and then they have some cooking utensils."
"And why," suggested George, laughingly, "couldn't we take some of the money along?"
"That would be a comfortable feeling to have plenty of money in our pockets. Very well, we'll take this afternoon for the trip."
An early start was made, the lamps carefully trimmed and the guns, together with the bolos, collected. It was a short walk to the opening, and Angel, although not invited, accompanied the party.
Together they descended, and soon reached the scene of the conflict at the large recess to the left of the entrance. The Professor, after reviewing the scene, suggested that the bones should be carefully gathered together and deposited at a place where they could be buried.