The fire blazed up in the chimney, and the shadows leaped and darted on the walls. A split log popped, and a blazing ember shot out across the hearth and landed close to Kent’s sleeping bag. He put his arm outside of the bag and flicked it back into the fireplace.
“If any of you get hot in the night, you’ll know that a spark landed on you,” he said.
“If you know so much, what made that wood pop like that?” Barry asked Mac.
“Expansion. Heat expanded it and made it burst.”
“All right. What made that popping sound?”
“That is a secret that we scientific men keep to ourselves,” answered Mac soberly.
“I wish you’d all quit talking about such nonsense and let me go to sleep,” grumbled Kent. “I’m tired after our tramping around today.”
“Yes, let’s go to sleep,” Mac urged. “Tomorrow I’ll explain all these deep things to you!”
“Thanks!” said Barry. “We can hardly wait until we hear them!”
The others were as tired as Kent, and they were willing to drop their good-natured conversation and drift off into slumber. Nor did it take them long. They were active and healthy boys, and sleep was a thing that they needed and enjoyed. In a few moments they were all breathing deeply, and quiet settled over the Bronson cabin.