Books: Uncle Robert\'s Geography (Uncle Robert\'s Visit, V.3)
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Francis W. Parker and Nellie Lathrop Helm >> Uncle Robert\'s Geography (Uncle Robert\'s Visit, V.3)
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"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 god and worshiped 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 space 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?"
[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.
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."
"I wish we could study the stars," said Frank.
"We will some time," replied Uncle Robert. "Come out on the piazza now,
and I will show you the north star. That will be a good beginning."
CHAPTER VII.
THE BAROMETER.
One day when it was Donald's turn to go for the mail he found among
Uncle Robert's letters a small paper. On the wrapper he read "United
States Weather Report."
It had come. There was already quite a line of figures in each of their
notebooks. Now they could see what this other record was like. As he
left the post office he stopped to look at the old thermometer beside
the door. Then he mounted Nell and rode down the village street and out
into the pleasant country road.
Uncle Robert was waiting for him on the porch, and as Donald rode away
to the barn, after giving him the mail, he heard him say:
"Here, Frank, is the Weather Report. Open it and look at it while I read
my letters."
Donald took off the saddle and gave the horse her supper. Then he
hurried back to see what Frank had found on the inside of the
important-looking wrapper. It proved to be a map with queer, crooked
lines all over it, but it did not look at all interesting.
"Here it says temperature," said Frank, pointing to a list of figures in
the corner. "Perhaps this is what we want."
"I don't see any numbers there like mine," said Donald, taking his
notebook from his pocket.
"Let me help you," said Uncle Robert, laying aside his letters and
coming to where they sat on the steps.
They made room for him, and, as he took the map, he explained:
"This, you see, is a map of the United States. These dotted lines tell
about the temperature. For instance, look at this one which is marked
fifty degrees. At every place in the country that is touched by this
line on the map the thermometer stood at fifty degrees at the time the
map was made."
[Illustration: United States weather map.]
"See," said Susie, "how crooked the line is. Why isn't it straight,
uncle?"
"Because," was the reply, "as I told you, it goes wherever the
temperature was fifty degrees. You remember, the first day we had our
thermometer, we found that there are many things which affect the
temperature. At some places along this line there are prairies, at
others forests, at others lakes, and here," pointing to the map, "there
are high mountains. All of these things affect the temperature, and that,
of course, changes the direction of the line."
"You say Chicago is the nearest station to us, uncle," said Frank,
looking down the temperature column. "My record for that day is not so
very different from the one given here for Chicago."
"Which shows that yours is probably as nearly correct as this is," said
Uncle Robert, with an encouraging smile.
"But I haven't one number in my book like that," said Susie, looking
disappointed. "I don't see why."
[Illustration: Susie's notebook]
"I do," replied Uncle Robert. "You make your record at noon, and of
course, it is warmer then. That is what your book says, does it not?"
"Yes," said Susie, "every number in my book is more than that one."
"That is right," was the reply, "for this record was made at eight
o'clock in the morning, which is nearer Frank's hour than it is yours.
So we would expect his to be nearer like this than yours, wouldn't we?"
"It isn't like mine either," said Donald.
"We may have one some time that will be more like yours," said Uncle
Robert, "for these records are made at eight in the evening as well as
in the morning."
"Uncle," said Frank, looking closely at the map, "here it says 'High,'
and there it says 'Low.' What does that mean?"
"It means," said Uncle Robert, "that here there is a low barometer, and
there the barometer is high."
"Barometer," said Donald. "What is a barometer, uncle? Is it like a
thermometer?"
"Well, not exactly," was the reply. "With the thermometer, you know, we
tell the temperature of the air, and with the barometer we tell how
heavy it is."
"How heavy the air is!" exclaimed Susie. "How funny! Why, uncle, air
doesn't weigh anything, does it?"
"More than you think, little girl," said Uncle Robert, smiling. "But
perhaps we can prove whether it does or not. Frank, will you get a pail
of water? Donald, see if you can find a cork some place; and Susie, run
in and get a tumbler."
When all was ready Uncle Robert asked Frank to fill the pan with water,
and Donald to put the cork into it.
[Illustration: Experiment No. 1.]
"There," said Donald, as the cork floated about on the pan of water.
"But I want the cork on the bottom of the pan," said Uncle Robert, "not
on the top of the water."
"It won't stay there," declared Donald, pushing it into the water again
and again with his finger. "It is too light. Corks always float."
"How can we make it go to the bottom?"
No one could tell. The children looked puzzled.
"Let us see what this will do," and, taking the glass from Susie's hand,
Uncle Robert turned it over the cork, pressed it down into the water as
far as it would go, and held it there. Looking through the glass, they
could see the cork lying on the bottom of the pan.
"Why, Uncle Robert!" exclaimed Susie, "what--how--"
"It's the glass that does it," declared Donald.
"But the glass doesn't touch the cork," objected his uncle.
"There's air in the glass," said Frank, who had been looking at it
quietly as the others talked. "That is what presses it down."
"If it's air," said Donald, "why didn't it go down before the glass was
put over it? There was just as much air about it then, and more, too."
"Let go of the glass, uncle," said Frank, "and see what it will do."
Uncle Robert did so, and the glass instantly turned over, while a big
bubble of air escaped through the water.
"There," said Frank, smiling, "I told you so!"
"Then air only presses on things when there is something like the glass
to hold it down. Is that so, uncle?" asked Donald.
"Let us see," was the reply.
[Illustration: Air Pressure. Experiment No. 2.]
Filling the glass with water, he placed a piece of paper over it, and
quickly turned it upside down. Not a drop of water fell from the glass.
The paper, now beneath the water, stayed there as though glued.
"Uncle," said Frank, "is it truly the air that holds the paper on and
keeps the water in the glass? If it presses that way everywhere, why
don't we feel it?"
"It is because it presses equally in every direction," replied Uncle
Robert. "Put your hand in this pail of water. Do you feel it pressing on
your hand?"
"No," said Frank.
"Place it lower in the water. Does it feel any heavier now?"
"Not at all," answered Frank.
"But you know that the water is heavy. Lift the pail, Donald."
"It is heavy," said Donald, setting it down. "I don't see why Frank
didn't feel a little of the weight of it when his hand was under all the
water."
"It is this way," explained Uncle Robert. "The water pressed on his hand
from below as much as from above, and the same on both sides. When you
lifted it you felt its weight pressing downward only. Now it is just so
with the air. It presses with such equal pressure that we do not realize
its weight. It is only when it presses harder from one direction than
from another that we feel it."
"That's when the wind blows, isn't it, uncle?" asked Donald.
"Yes, my boy," was the reply. "You can see how it is out among the trees
now."
"But, uncle," said Donald, "how can the air be weighed if it presses the
same in all directions? It was only when I lifted the whole pail of
water that I felt how heavy it was. The air can't be weighed if it
presses up just as much as it does down."
"But if in some way it could be shut off so that it would only press in
one direction?"
"It might be," answered Donald, "but I don't see how."
Uncle Robert told Susie to put the glass in the water so that it would
all be below the surface, and, without taking it from the water, to turn
it upside down. She did so, and then began to lift it slowly out of the
water.
"See," cried Susie, "the water comes with it. The glass is full. Could I
lift it clear out that way?"
"Try it," said Uncle Robert, smiling.
But no; when the edge of the glass came out of the water in the pail,
down went the water with a splash.
"I see how it is," said Frank, who had watched it closely. "There wasn't
any air in the glass to keep the water out, as there was when we turned
it over the cork, so the water stayed in it."
"But what made it come up out of the pail?" asked Donald. "There wasn't
any air under it to press it up."
"Would the air pressing on the water around the glass make it do so,
uncle?" asked Frank, placing the glass in the water and raising it as
Susie had done. "It seems as if it might be that."
"That is what it is," replied his uncle. "The air pressing on the water
in the pail forces it into the glass, where there is nothing to keep it
from rising."
"If the glass was longer would the water stay in it just the same?"
asked Donald.
"Yes," was the reply. "If there was no air in the glass it would have to
be very many times as long as this glass is to hold the water that would
rise if it had a chance. But come, let us sit down on the steps again,
and I will tell you about it."
When they were settled he continued:
"Over two hundred and fifty years ago there lived a man named Galileo,
who learned a great many wonderful things by studying the stars and
doing just such things as we have been doing. It was he who made the
first thermometer. But there was one question that he could not answer.
He found that in a hollow glass tube, closed at one end, water would
rise thirty-four feet high, but no higher. He could not tell why. A pupil
of his thought he would try the same thing with the heaviest liquid
known----"
"That was mercury, wasn't it, uncle?" interrupted Donald.
"Yes; he used mercury, and found that it rose in the tube just thirty
inches. He knew that the mercury was thirteen and six-tenths times as
heavy as the water, so he felt sure that it was the pressure of the air
that made them both rise in the tube, for thirty-four feet is just
thirteen and six-tenths times thirty inches. But they wanted to see if
it was really the air, so they took the tube up on a high mountain."
"What difference would that make?" asked Susie.
"Look at the woodpile out there," said her uncle. "Where do you think
the weight of the wood would be the greater? On the ground or halfway to
the top?"
"On the ground, of course," answered Susie.
"Well, they found it was the same with the air. As they went up the
mountain the mercury in the tube fell."
"That showed that the weight on it was less, didn't it, uncle?" said
Frank. "I think that was a very wonderful discovery, don't you?"
"It was, indeed," replied Uncle Robert, "and that is how the first
barometer was made."
[Illustration: Barometer.]
"Is that what a barometer is?" asked Donald.
"Yes," was the reply, "simply a glass tube about thirty-three or
thirty-four inches long, closed at the top, and filled with mercury. It
is then placed in a small open cup, called the cistern, into which the
mercury flows until the air pressing on it there will let it fall no
farther."
"Does it always stay at the same height in the tube?" asked Donald.
"Oh, no," his uncle answered. "Some days the air is heavier than others,
and so presses harder on the mercury."
"That would make it rise, wouldn't it?" asked Susie.
"Yes, dear."
"So, uncle," said Frank, taking up the Weather Report, "where it says
'High' here, it means that the air is heavier than where it says 'Low.'
Is that it?"
"That's right," replied Uncle Robert; "and when the barometer is low we
know there will be a storm."
"Well"--and Donald stood up and stretched himself--"I wish I could see a
barometer."
"You shall," said Uncle Robert "I will send for one. You may carry the
letter to the post office to-morrow when you go for the mail."
CHAPTER VIII.
A WALK IN THE WOODS.
It was a beautiful Sunday afternoon. The sun had marked its shortest
shadows. They were now pointing toward the northeast.
The family had returned from the little village church. Dinner was over,
and they had all gone into the cool, shady piazza. Mrs. Leonard and
Susie had settled themselves cozily in one corner and were reading
together. Mr. Leonard was nodding over the pages of his weekly
newspaper. Frank, stretched out on the settee, was absorbed in a new
book, while not far away Donald lay under the spreading branches of a
spruce tree with Barri by his side. Uncle Robert stood gazing at the
green woods, which looked so cool and inviting.
"'The groves were God's first temples,'" he said to himself, and then,
turning to the others, asked, "Who wants to go for a walk?"
"I do," said Frank, springing up. "Come on, Don. Don-ald!" he called,
"we're going for a walk."
"You'd better come with us," said Uncle Robert to Mrs. Leonard.
"I'll get your hat, mother," cried Susie eagerly, running into the
house.
"Shall we go to the cornfield?" asked Mr. Leonard, picking up his straw
hat.
"I think it would be cooler in the woods," said Mrs. Leonard.
"Oh, yes," said Donald, "let's go up the creek to the pond."
The country was in the full glory of early summer. Just beyond the rich
green of the great cornfield could be seen the peaceful river. The
yellowing grain on the upland waved gently in the breeze. Under the
wide-spreading oak trees in the pasture the cows were lazily chewing
their cuds. A feeling of quiet pleasure filled the air.
"I planted all these trees," said Mr. Leonard as they walked under the
maples that grew on either side of the road. "It is wonderful how they
have grown. They were like little sticks when I set them out."
"The one at the end of the row," said Mrs. Leonard, "was planted the day
Frank was born."
"It is the largest of them all," said Frank.
"That's because it was planted first," said Susie. "I have a tree, too,
uncle."
"So have I," said Donald. "It is the spruce in the front yard."
"We call them our birthday trees," said Susie. "Mine is the elm by the
corner of the porch."
"That is a very nice custom," said Uncle Robert. "But the trees grow
faster than you do."
"They don't have anything to do but grow," said Donald.
When they reached the bridge they paused to look up and down the creek
valley. Through the trees they caught glimpses of the shining river and
the waving corn. The creek, a little stream, flowed between the two
gentle slopes that formed its valley.
"There's a gate under this bridge, uncle," said Donald, "to keep the
cows from going down the creek to the cornfield. In the fall, after the
corn is cut, we open it, and let them go to the river."
"How pleasant it is in here!" said Uncle Robert as they walked farther
into the wood.
"Just see how damp the ground is under these dead leaves!" said Susie as
she pushed them back from a little violet that she was trying to pick
with a long stem. "Poor little flowers! How do they ever get through all
these leaves? It would be so much easier for them if it was just green
grass."
[Illustration: The bridge. ]
"But then there wouldn't be any flowers," said Mr. Leonard, "or at least
they would be very different."
[Illustration: HICKORY OAK WILLOW BUTTER-NUT MAPLE WALNUT (leaves)]
"It's the leaves that make the soil so rich," said Frank, digging into
the ground with a stick. "See how they are mixed all through it!"
"Do you know the names of all these trees?" asked Uncle Robert.
"I do," said Frank. "I can tell every tree in the wood."
"How?" asked Uncle Robert.
"By the leaves is the easiest way," said Frank, "but I know some trees
by the bark."
"I can tell them by the leaves," said Donald. "Try me."
So as Uncle Robert pointed to them Donald called them all by name. There
were oaks and maples, hickories, walnuts, and butternuts, and close to
the creek the overhanging willows.
"Can you tell a tree by its shape when you look at it from a distance?"
asked Uncle Robert.
"I can tell the willows and poplars," said Frank, "and maples, too."
"The trees in the pasture have a different shape from those in the
woods," said Uncle Robert. "I mean trees of the same kind. How do you
explain that?"
"Why, the trees in the pasture have a chance to spread out," said
Donald. "There isn't so much room in here."
"But these trees are taller," said Frank, "and they are straighter,
too."
"Can you tell the direction of the winds that blow the strongest and
longest by the shape of the trees?" asked Uncle Robert.
"I never thought of that," said Frank.
"The wind doesn't blow in the woods," said Donald.
"When we get out into the pasture we'll notice the trees there," said
Mr. Leonard.
"Isn't this a tiny tree?" said Susie. "I wonder what it is."
"That's an oak," said Frank. "The leaves tell that."
"Oaks grow from acorns," said Donald. "I'm going to dig this up and see
if it grows like the seeds in the garden."
"What a long root it has!" said Susie as Donald dug about it. "Don't
take it out, Don. Put the dirt back and let it grow to be a tree."
[Illustration: Oak sprout.]
"How long will it be before it gets as big as these trees, uncle?" asked
Frank.
"A great many years. Perhaps your father can tell about how old some of
these trees are."
"I have cut some," said Mr. Leonard, "that were about a hundred years
old."
"Why, father," exclaimed Susie, "how could you tell?"
"Do you know how the end of a log looks when it is sawed off straight?"
"I do," said Frank. "There are light and dark rings in it."
"Well," was the reply, "one of these rings grows every year."
"So if you count the rings you can tell how old the tree is," said
Donald. "Isn't that great!"
[Illustration: End of a log.]
"What time of the year do the trees grow the most?" asked Uncle Robert.
"In the spring I should think," said Frank. "That's when the sap begins
to run."
"What is sap?"
"It must be the water that the trees take up from the ground," said
Frank.
"We've tapped some maple trees for sap," said Donald.
"And we could see it run right out of the tree," said Susie.
"I've told the children how we used to make maple sugar in New England,"
said Mrs. Leonard. "Do you remember, Robert, what a quantity of sap it
took to make just a little sugar?"
"Yes, and I also remember how long I thought it took to boil it down
into the wax I was so fond of."
"About thirty gallons of sap can be taken from one tree each year," said
Mr. Leonard.
"But I should think that would hurt the tree," said Frank.
"No," replied Uncle Robert, "for the hole they make is only about an
inch across. If they were to cut all around the tree, you see, it would
stop the running of the sap and kill the tree."
"That is called girdling," said Mr. Leonard. "They used to clear off
hundreds of acres of land in that way when this country was first
settled. Instead of cutting down the trees, they girdled them near the
ground. In a very short time they died, because they could get no food
from the earth. The dead trees lost their strength, and a strong wind
would blow them over. Then they were piled up and burned."
"How do you know when a tree is dying?" asked Uncle Robert.
"The leaves turn yellow," said Donald.
"But the leaves turn yellow in the fall," said Frank, "and the trees do
not die."
"The leaves of my spruce don't turn yellow in the fall," said Donald.
"They stay green all winter."
"What makes the leaves green?" asked Uncle Robert.
No one answered.
"What is the color of the potato sprouts in the cellar?"
"Yellow," said Susie.
"When you take up a board that has lain on the grass, what is the color
of the grass?"
"Yellow," said Donald.
"Why?" asked Uncle Robert.
"Because they don't get any light," said Frank.
"You know why we put our plants in the south window in winter?" said
Mrs. Leonard.
"Oh, yes," said Susie, "because the sun shines in at that window."
"Warmth and water and air help trees and plants to grow," said Uncle
Robert, "but without sunlight their leaves would be yellow and their
stems and branches weak. The greatest forests on earth are where it is
very hot and moist. The sun is a wonderful artist, and every leaf it
paints makes the tree stronger."
"But what makes the leaves turn yellow and red just before they fall
off?" asked Frank. "Does the sun paint them then?"
"That is a question that no one has been able to answer," replied his
uncle.
"But how can the sap flow up the tree?" said Donald. "I should think it
would run down."
"It would unless there was something to draw it up," said Uncle Robert.
"I suppose the sun does that, too," said Frank.
"Where does it go after it reaches the leaves?" asked Uncle Robert.
"Why, back again," said Susie.
"No, it doesn't go back--not a drop," laughed Uncle Robert.
"Does it dry up?" asked Donald.
"What do you mean by drying up?"
"It evap-o-rates," said Donald, who liked to use large words.
"Does it all go into the air?" asked Frank.
"I want you to answer these questions yourselves, children. What do you
see on the corn leaves in the early morning?"
"Drops of water; but that is dew, isn't it?" asked Frank.
Uncle Robert had a way of stopping or changing the subject when he had
asked certain questions. He knew that the children would think of them
again and try to answer them.
"Let's sit down on this log," said Susie. "I want to fix my flowers."
As they sat there squirrels ran up the trunks of the trees and laughed
at them from the branches.
"That is a good shot," said Frank, pointing to a large fox squirrel.
"But he knows we won't kill him, and that's the reason he shows
himself."
"Is it right to shoot the pretty squirrels, Uncle Robert?" asked Susie.
"I thought so when I was a boy. I shot a great many of them then. It was
fun for me, and I felt very proud when I brought home half a dozen
grays.
"Once I went home from the city for a summer's rest. I took my gun for a
stroll in the oak woods where I had shot so many squirrels. I put my gun
against a tree and lay down upon the leaves. Soon I was fast asleep. I
dreamed of a group of merry, laughing children running, scampering,
playing."
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