I'm pretty sure that that rock we climbed out on this morning when we were swimming was volcanic." "Sure," agreed Perry.

"It was pumice stone.

I meant to bring a bit of it along for you to clean your hands with." "I didn't say pumice," replied Ossie haughtily.

"It was more probably obsidian." "My idea exactly! In fact, it had a very obstinate feeling.

It--it left quite an impression on me!" The _Follow Me_ developed engine trouble that morning and they lay by for a half-hour or more while Tom Corwin toiled and perspired, argued and threatened.