"Yes, mother asked him to come and spend a week, and he said he would.
We'll have some fun in the cave."
"What do you suppose the big hole can be?" asked Mrs. Martin, when Grandpa Martin and the children reached camp after their visit to the strange place.
"I don't know," he answered. "It doesn't seem to have been dug with picks and shovels. It's just a natural cave I guess, and some fishermen may have eaten their lunch there one day when it rained. But there is no one in it now."
Ted and Jan talked much about the cave the rest of that day. They went for a ride in the wagon drawn by Nicknack, taking Trouble with them. On their way back Jan said:
"Oh, I wish I had a swing."
"It would be fun," agreed Ted. "Maybe I can make one."
"You'll have to get a rope," said his sister. "Grandpa is going to row over in the boat to-morrow. Ask him to bring us one."
"No, he don't need to bring us a rope," went on her brother.
"Why not?"
"'Cause I can get a rope in the woods."