“The dry air and all--” suggested Beatrice.

Stern nodded.

“Yes,” he answered. “Intact, so far. But--”

He stirred the skull with his foot. Instantly it vanished into powder.

“Just as I thought,” said he. “No chance to give a decent burial to this or any other human remains we may come across here. The slightest disturbance totally disintegrates them. But with this it's different!”

He picked up a revolver, hardly rusted at all, that lay near at hand.

“Cartridges; look!” cried Beatrice, pointing.

“That's so, too--a score or more!”

Lying in an irregular oval that plainly told of a vanished cartridge-belt, a string of cartridges trailed on the concrete floor.

“H-m-m-m! Just for an experiment, let's see!” murmured the engineer.