The earth does not seem round to us. The fields and the village, or the city where we live, may be flat. Some places look as flat as a floor. But still the earth is round.
Can we suppose that the little ant on the orange thinks that the orange is round? If he thinks at all, he must think it is flat.
We are so large that we see a large part of the orange at once. Hence we can see that it is round. The small ant sees only a small part of the orange at once, and that part seems flat.
If we could stand off and look at the earth as we look at the orange, then we should see that it is round. But we cannot get far enough from the earth to do this; we can see only a very small part of it at one time. This is the reason that it seems flat to us.
The Earth as it would look if we could see it from the moon.
2. Size of the Earth.—Suppose a carrier dove should fly round the earth. A swift carrier dove can fly 100 miles an hour. If it was to fly at that rate, without ever stopping, it would be more than ten days in going round the earth.
If a man could walk round the earth, and went 50 miles a day, the trip would take him more than sixteen months.
What a big ball the earth must be! We know about how much a mile is. The distance round the earth is 25,000 miles. This distance is called the circumference of the earth. The distance through the earth is about 8,000 miles. This distance is called the diameter of the earth.
The distance through the earth is a little greater at the equator than it is at the poles. If you press an orange between your thumb and linger and flatten it a little, it will have about the same shape as the earth.
For Recitation.—What is the shape of the earth? How do we know this? Why does the earth seem flat to us? How far is it round the earth? How far is it through the earth?
LESSON VI.
THE SURFACE OF THE EARTH.
Preparatory Oral Work.—Teach the word surface. Touch the surface of the globe; of the desk. Teach that one is a flat and the other a curved surface. In the same way teach the word interior.
Show the pupils how the waves dashing against the rocky coast might tear it down, and by pounding the torn pieces and rolling them about might grind them down to pebbles and sand.
1. Land.—The outside of the earth is called its surface. One part of the surface is solid, or hard. This is called the land.
We live on the land, and build our houses and towns and cities upon it. Trees and other plants grow on the land, and animals live on it.
2. Water.—But there is a large part of the surface of the earth which is water. Most of us have seen a pond, and we all know what a pond is. Now suppose a pond were made ever so large, hundreds and thousands of miles across, instead of a few yards. There is a pond as large as that. It is called the sea.
How large do you think it is? A boat can sail across a small pond in a few minutes, but it takes a sailing vessel about fifty days to sail across some parts of the sea. Think of being on the water seven weeks without seeing land!
We can see in the picture above that the water surface is very much larger than the land surface. There is nearly three times as much water as land.
Under the water is land which is much like other land except that the water covers it. Strange plants grow on it. There are no daisies or buttercups, but there are seaweeds of beautiful colors, purple and yellow and red and green. The fishes, you see, have their gardens as well as we.
