me, I think I’ll return to the ledge. There are some very attractive fossils—”
“Jumping catfish!” said Danny. “Wait a minute, sir. I—I really think you ought to start for town. If you got in on the early train, Professor Bullfinch will be worrying about you. It’s past eleven o’clock.”
“Hmm. Yes, I suppose you’re right.” Dr. Tresselt shaded his eyes with his hand and looked about. “Unfortunately, I haven’t the faintest idea how to get back to town. But never mind. Bullfinch will certainly find me. He was always very good at that sort of thing when we were in school together. Goodbye.”
And with that, he turned away.
“Dr. Tresselt!” cried Danny. “Gee, excuse me, but—well, we know the way to town.”
“Of course you do,” the geologist beamed. “An excellent idea. You run along and tell Bullfinch where I am. He’ll understand.”
He waved his hand at them and started to climb the ridge.
“What’ll we do?” Irene whispered. “Just leave him?”
“We can’t,” said Danny. “It wouldn’t be fair to the Professor. Anyway—he forgot his hammer.”
At that moment, Dr. Tresselt returned. “My hammer,” he said, apologetically. “Thanks very much.”
“Listen, Dr. Tresselt,” Danny said, desperately, “I know my mother’s expecting you for lunch. She’ll be very disappointed. And I know the Professor’s looking forward to seeing you. I really think you ought to come along with us. Then you can come back up here this afternoon, or tomorrow. After all, you are supposed to stay for a week.”
“Yes, that’s true.” Dr. Tresselt tapped the hammer against his palm. “I mustn’t be so selfish… The fact is, you see, I’m afraid I sometimes let my interest in my work get the better of me. You’re quite right, of course.”
He straightened, decisively. “You’re a very good conscience, Danny. I ought to hire you. Let’s go, then.”
They started off together, directly down the hill, knowing that sooner or later they’d come out in the meadows above the town. But they had only gone a short distance when Joe, pointing ahead, said, “Hey, look, Dan! That big white oak on the point of rock. Isn’t that the one—?”
Danny glanced at it. There, sure enough, was the tree which marked the site of the cave. He looked at his friends, and then back at Dr. Tresselt, strolling behind them and whistling happily. He heaved a deep sigh. He knew perfectly well that if the geologist saw the cave, he would go no further.
Then he did one of the bravest things he had ever done. “It’s just an old tree,” he said. “Come on, let’s get Dr. Tresselt home.”
CHAPTER THREE
Channel 25
They went, first, to the railroad station to pick up Dr. Tresselt’s suitcase, and then took a taxi home. Professor Bullfinch came out to meet the cab and greeted his old friend enthusiastically.
“My dear Alvin,” he said. “Glad to see you. Up to your old tricks, eh?”
“I couldn’t resist the hills, Euclid,” said Dr. Tresselt. “Some beautiful limestone! If these youngsters hadn’t dragged me away, I’d still be there.”
Professor Bullfinch took off his glasses and wiped them, chuckling. “I’m grateful to you, all three,” he said.
“But weren’t you worried?” asked Irene. “The train came in at nine o’clock. We thought you’d have the police out looking for Dr. Tresselt.”
“Oh, Dr. Tresselt always manages to find his way back somehow,” the Professor said. “He was lost in the Navajo desert for three weeks, once, but he found himself all right in the end, and brought back a very important report on rock formations, as well.”
“I’ve heard about absent-minded professors…” Joe whispered to Danny.
The Professor overheard him. “Not absent-minded, Joe,” he said. “People say that of scientists because they don’t understand how fascinating our work can be. It can absorb your attention so that you forget everything else. Dr. Tresselt is far from absent-minded in everyday affairs—I’ve never known him to wind up the cat and put the clock out, for instance—but when he is at work on a project, he tends to forget the rest of the world.”
Joe blushed. “I’m sorry,” he said. “I guess I know what you mean. It’s the way I am when I’m working on a poem, for instance.”
“Exactly,” said Dr. Tresselt. “In fact, scientists and artists are alike in many ways.”
They all went into the house, and Mrs. Dunn, a comfortable, jolly-looking woman with hair as red as her son’s, shook Dr. Tresselt’s hand.
“Professor Bullfinch told me we might not see you until dinner-time,” she said. “Fortunately, I didn’t believe him. Lunch will be ready in a few minutes. Come along, Dr. Tresselt, and I’ll show you to your room.”
The three grownups went upstairs. Danny sighed, jamming his hands deep into his pockets.
“Well, I’m glad we got him home,” he said. “But I sure hated to leave that cave.”
“What?” said Joe. “You mean that the tree I saw really was the one that marked where the entrance was?”
“I knew that,” Irene said, quietly. “And Danny, I think it was—well—noble of you.”
Danny shrugged, kicking at the rug with one toe. “Yeah, I must have been sick or something. I’ll just never find the way back to that spot.”
“Yes, you will,” Irene smiled mischievously. “I dropped back, you know, and when I did I spotted the cave entrance. So, as we went down the hill, I marked the trail by breaking twigs so that they pointed back toward it, and by tying knots in the long grass. We can find the way easily.”
Danny brightened. “Gosh, Irene, you’re great! I was so busy with Dr. Tresselt that I never even thought of doing that.”
“He’s nice, isn’t he?” Irene said.
“There’s one thing,” said Joe. “How could you tell that was a geologist’s hammer? I didn’t know geologists went around hammering things.” He scratched his head. “To tell the truth, I don’t know what they do go around doing.
“Geologists study the earth,” Danny replied. “They study the rocks, and how mountains were formed, and how old the earth is, and what happens to rivers and lakes and oceans. They have to know all sorts of sciences—botany, chemistry, physics, mineralogy. They have these special hammers, with narrow heads and sharp picks on them, so they can take samples of rocks and minerals.”
He turned down the long hall that led to Professor Bullfinch’s private laboratory, which was built on to the back of the house. “Let’s go look in the Professor’s library,” he said. “I want to see what Dr. Tresselt meant when he talked about ‘sedimentary rock.’”
“I’ll
