"Of course we can," said Frank. "We can use the house. That always stands still."
"The house might do," said Uncle Robert; "but wouldn't it be better to have a shadow stick?"
"Where can we get one?" asked Donald.
"What is it made of?" asked Frank.
"It is like this," said Uncle Robert, taking paper and pencil from his pocket. "There is one long piece of board, and one short one nailed to the end—so," drawing it on the paper.
"Oh, that's easy enough made," said Donald. "We can do it ourselves right here in the tool house."
"Let's make it to-morrow, Don," said Frank.
"It must be set up some place with the upright end turned toward the south, so that just at noon the shadow of the short piece may fall straight on the board. By drawing a line across the board at the top of the shadow and marking the date on it, we can tell how the length of the shadow changes."
"Uncle," asked Donald, "when it is winter here, is it summer in some other part of the world?"
"Yes," was the reply, "and now that our summer is coming, the people there are beginning to have winter."