ther Ace nor Ted had ever been troubled
with that malady. The next day they flew farther, carrying with them an
emergency camp kit. They landed about every two hours, rested awhile, and
finally went into camp about four in the afternoon, intending to take a
look in the night to see if the fugitives would betray themselves by a
bon-fire. They camped in a meadow where they had seen something like
smoke arising. This proved to be steam from a hot spring, and they
thought with longing how fine their chilled bones would feel in a good
hot bath. But the spring water came too hot. (If they had had eggs, they
could have cooked them in it.)

Then it occurred to them to dig a little trench, line it with stones, and
carry the spring water by the folding canvas pailful to fill it. It would
quickly cool to the right temperature. The scheme worked wonderfully.

The water had a strong mineral taste, not altogether agreeable, but its
effect on aching bones was wonderful. A flint arrowhead buried in the
soil they excavated told its tale of Indians, who must have valued the
spring and fought for its possession against covetous tribes.

"What makes these hot springs, anyway?" asked Ted. "Have you had that yet
in your geology?"

"Yes, but you'll understand better when Norris tells us the story he's
promised about the formation of the earth. I'm no professor." And he
turned a former laugh on Ted. "Tell you what, Old Top, once we get these
fire bugs located for our Uncle Sammy, what say we fly up and have a look
at Lassen volcano before I send the 'plane back?"

"Bully! I'd like to fly over a glacier, too, and see what it looks like.
Can you go that high?"

"I--guess so. Never tried it! We will, though!"

"Gee! Wouldn't this be a great way to teach geography--from an aeroplane!"

"Sure would!--Great way to go camping, too."

"'S right, only--it would be if there was just the two of us," sighed
Ted ungrammatically. "Could you carry enough grub?"

"We could get fresh supplies every few days, from some ranch."

The next day they went back for the rest of the party and showed them
Ted's fossil, entering the cave the way Radcliffe had left it. Norris had
spent one summer with fossil hunters in the dry gullies of the Southern
end of California, he told them, where through scorching days and thirsty
nights they had searched for any bit of bone that might lie amid the
shale or imbedded in strata the edges of which might be seen on the fac