QUESTIONS.

1. Where is Jupiter? Which is the largest planet? What is the diameter of Jupiter? Its distance from the sun? How long is its revolution round the sun? How long is it turning on its axis? What is the length of the days and nights in Jupiter? 2. What is its degree of light and heat? 3. How many moons has Jupiter? Do they revolve round Jupiter all in the same time? 4. How does Jupiter appear through a telescope?

CHAPTER XLVIII.

ABOUT SATURN.

1. SATURN is nine hundred millions of miles from the sun, and performs its revolution in about thirty years. It turns on its axis in little more than ten hours. It is supposed to be eighty times colder upon this planet than upon the earth. Saturn is seventy-eight thousand miles in diameter; and, excepting Jupiter, it is the largest of the planets.

2. Saturn has seven moons or satellites, which revolve round it in different periods of time: the shortest period is one of our solar days, and the longest eighty days.

3. Saturn is surrounded by an immense thin ring, or rather by two rings, one within the other. These rings turn round the planet from west to east, and complete their revolution in ten hours. The light of the sun, falling upon them, gives them a bright appearance,

even brighter than the planet itself. When viewed through a telescope, Saturn appears to have spots and

belts upon its face, like Jupiter. Stars are also sometimes seen between the two rings, and between the inner ring and the planet. The distance of the inner edge of the inner ring, from the surface of the planet, is about thirty-four thousand miles.

QUESTIONS.

1. How far is Saturn from the sun? How long is it revolving round the sun? How long turning on its axis? Is it colder upon Saturn than upon the earth? What is the diameter of Saturn? 2. How many moons has it? 3. By what is it surrounded? Do these rings revolve round Saturn? What makes them look bright? How does Saturn appear through a telescope? What are sometimes seen between the rings and Saturn? How far is the nearest ring from Saturn?

CHAPTER XLIX.

ABOUT THE PLANET HERSCHEL, OR URANUS, OR THE GEORGIUM SIDUS.

1. THIS planet is scarcely visible to the naked eye, and little was known about it till 1781, when Sir William Herschel discovered it to be a planet, revolving round the sun; and in honour of his august patron, King George the Third, named it Georgium Sidus, or the Georgian Star. It has since been sometimes called Herschel, and sometimes Uranus.

2. This planet is at the prodigious distance of one thousand eight hundred millions of miles from the sun. It performs its revolution round the sun in eighty-four years. The time in which it turns round upon its axis is not known. It is three hundred and sixty times colder upon Uranus than it is upon the earth, and the degree of light is called three hundred and sixty times less. There are six satellites or moons revolving round this planet, but not a great deal is known about them.

QUESTIONS.

What

1. Is Herschel a planet? When was it found to be one? other names has it? 2. How far is Herschel from the sun? How long is it revolving round the sun? What of its light and heat? How many satellites or moons has Herschel revolving round it?

CHAPTER L.

ABOUT THE MOTIONS OF THE PLANETS.

1. I MUST now beg the particular attention of my little readers to what I am going to say. The planets, or planets and asteroids, of which I have been telling you, have each of them two motions. That is, they all turn round from west to east, in the same manner as the earth, of which I told you a little while ago; and they also move in vast circles round the sun. To make you understand this better, suppose you put a small stick through the centre of an apple, and call the stick its axis. Now, turn the stick round, and see the apple turn with it. Very well! The apple turns round on its

axis.

2. In a similar manner, each of the planets turns round upon its axis. The earth turns round upon its axis every day, or once in twenty-four hours. Some of the planets turn round upon their axes in a shorter time than the earth, and some of them in a longer time.

3. Now, suppose you take an apple, and tie a string to the stem of it, and whirl it about your head. We will call the circle, or path in which the apple flies about your head, its orbit. So, if you whirl it swiftly, the apple will go round in its orbit, or go round your head, a hundred and fifty times in a minute.

4. Now the planets go round the sun in their orbits, or in great circles, just as the apple tied to a string flies

round your head. Some of them are nearer the sun than others; and, not having as far to go, for that reason they complete their journey round the sun in a shorter space of time.

5. The earth goes round the sun in its orbit once in a year, or three hundred and sixty-five days, and the whole distance which it travels in this time is truly wonderful. It is more than five hundred millions of miles. The rate at which the earth moves in its path is nearly fifteen hundred thousand miles a day. We, who live upon its surface, proceed along with it in its journey; and are therefore borne along at the prodigious rate of about sixty-four thousand miles an hour, or about eleven hundred miles a minute!

6. This is truly an amazing subject for contemplation. While you are counting one hundred, you are carried through space eleven hundred miles!

QUESTIONS.

1. What two motions have all the planets and asteroids? 2. How often does the earth turn round upon its axis? What is the axis of the earth? What is the orbit of the earth? Do all the planets turn round upon their axes in the same time? 4. Do all the planets revolve round the sun in the same time? 5. How long does it take the earth to go completely round the sun? What number of miles does the earth travel in completing one revolution round the sun? How many miles does the earth travel in a day? How many miles are we carried through space upon the earth in an hour? How many in a minute?