Uncle Robert's Geography Part 13

"Do you know," said Uncle Robert, "there are places all over the United States where such records are kept? They are published, and I am to have them sent to me every week."

"I wonder if ours will be like them," said Donald, turning over the pages of his notebook.

"Even if they should be different." said Uncle Robert, "they may be just as true."

"We'll get up early and start the shadow stick the first thing in the morning," said Frank, "so as to have it ready by noon."

"How do you know when it is noon?" asked Uncle Robert.

"We look at the clock," said Susie.

"But noon by the clock is not always noon by the sun," replied Uncle Robert.

"How can that be?" asked Donald.

"It is noon somewhere on the globe every minute of the twenty-four hours," said Uncle Robert. "The sun is always setting and always rising somewhere."

The children were puzzled.

"I don't see how that is," said Donald.

"Let us see if we can find out," said Uncle Robert. "Frank, you stand at the east end of the room, Donald at the west, and Susie in the middle.

Now, we'll play that Frank is in New York, Susie here at home in Illinois, and Donald in Denver. I'll take the lamp and be the sun. You are shadow sticks, you know. Now watch the shadows, and see when they point directly north."

Uncle Robert took the lamp and walked slowly from the east side of the room.

"My shadow points north," said Frank as Uncle Robert pa.s.sed him.

"Now mine does," said Susie.

"And mine last of all," said Donald.

Uncle Robert took out his watch. It was ten minutes past eight.

"That is Susie's time," he said. "Would it be the same in New York, Frank?"

"I think it would be past that," said Frank, "but I don't know how much."

"It is ten minutes past nine by the watch in New York," said Uncle Robert.

"When would it be that time in Denver?" asked Donald.

"In an hour by the watch," said Uncle Robert, "but it would not be the same by the sun."

"Then the watches don't tell the true time, do they?" said Frank.

"The sun's shadows give us the true time," said Uncle Robert. "We will study the shadows, and by and by may learn how the watches and clocks are regulated. But how do you think people told the time before they had clocks?"

"It must have been by the sun," replied Frank.

"I can tell by the sun when it is noon," said Donald, "but I don't see how any one can tell any other hour that way."

"How do you know when it is noon?"

"Why, the sun is highest at noon." said Donald. "and the shadows point straight toward the north."

"Early in the morning they point to the west," said Frank, "and in the evening they point to the east."

"The people who lived in the world many hundred years ago observed the same thing," said Uncle Robert. "There was nothing so strange to them as the rising and setting of the sun. They loved the light that came with it. They feared the darkness that followed its going away. They told many interesting stories to explain this continued appearance and disappearance. Some thought the sun was a king riding through the sky in a golden chariot. Others looked upon it as a G.o.d and wors.h.i.+ped it.

"They soon learned that when it went away it was sure to come again, and as they saw how regularly it moved, they felt there must be some power back of it to guide it. Through this they were led to a belief in a Being that controlled all things.

"They watched the shadows, too, and saw them change just as you see them every day. They learned that the shadow is shortest when the day is half gone, and they called that time midday. So, by studying the length and direction of the shadows, they soon became able to judge the time of day.

"Then some one thought to set up a rod and mark the places where the shadow fell at sunrise, at sunset, and at midday. The s.p.a.ce in between was divided for the hours. This was called a sun dial and was the first instrument ever made for telling time."

"When was the first one made?" asked Frank.

"That is not known," replied Uncle Robert, "but we read in the Bible of the sun dial of King Ahaz, who lived about eight hundred years before the time of Christ. That is the first record we have of one."

"How was it made?" asked Donald.

"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?"

[Ill.u.s.tration]

"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.

Susie went to the window and looked out at the clear star-lighted sky.

"Uncle," she said, "the stars all look alike to me, only some are little and some are big. How can people know them by their names?"

"Just as anything else is known, dear," replied Uncle Robert, "by close and careful study."