"I do not know how the one King Ahaz used was made," said Uncle Robert, "but I can show you how one looked that I saw in an old garden in England. This," drawing a half circle, "is the dial on which the hours were marked. Around this dial there was a border, much cracked, and crumbling away, but I could read the words, 'The sun guides me, the shadow you.' The rod, or gnomon, as it is sometimes called, stood just halfway between the ends. Where would the noon shadow fall, Susie?"
[Illustration]
"In the middle, wouldn't it?" answered Susie.
"And the morning shadow would fall on the west and the evening shadow on the east side," said Frank.
"Now we'll put in the shadow stick," said Uncle Robert, drawing a triangle on the paper.
"Why don't you make it stand up straight?" asked Donald.
"The shadow does not tell the truth," said Uncle Robert, "unless it points in the same way that the north pole does, and that, we know, points to the north star. I will explain this some other time."
"Couldn't we make a sun dial?" asked Donald. "I don't believe it would be very hard."
"You could make one easily," answered Uncle Robert.
"But let's have the shadow stick first," said Frank.