"I wish when books tell things they'd tell why they're so," said Frank.
"Perhaps if we think about these things," said Uncle Robert, "we may be able to answer some of the 'whys' for ourselves."
"We can tell by the thermometer just how warm it is every day," said
Susie, "but it won't tell us why."
"The shadow stick may help us there," said Uncle Robert.
"I am afraid I shall forget," said Donald.
"I have some little notebooks in my trunk," said Uncle Robert. "Suppose I give you each one and let you write down what the thermometer and the shadow stick say every day."
"What fun that'll be!" cried Susie. "When may we begin?"
"To-morrow morning, if you like," replied her uncle. "I will get the books for you now."
He went away to his room, and soon returned with the notebooks.
"I'll tell you, uncle," said Frank as he thanked Uncle Robert for his book, "how would it do for each of us to look at the thermometer at a different time of the day?"