ELEMENTS

OF USEFUL

KNOWLEDGE.

PART V.

1 Q.

ASTRONOMY.

WHAT is Astronomy?

A. The study of the Heavenly Bodies, their proper Places, Motions and Use. 2 Q. What is the Universe?

A. That wide Expanse in which all Bodies have their Existence.

3 Q. What is a System?

A. A number of Bodies, which move about one common Centre or Point.

4 Q. To what Part of the Universe do we belong?

A. To the Solar System; so called, because the Bodies which compose it ove round the Sun as their Centre.

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5. Q. What is the Sun?

A. A Body of Fire, which by its Warmth and Heat promotes the Growth of Vegetables, cherishes Animal Life, and raises Vapours from the Sea, without which we should have no Rain.

6 Q. What Bodies belong to the Solar System?

A. The Planets, their Moons, and the Comets.

7 Q. Name the Planets?

A. Mercury, Venus, the Earth, Mars, Jupiter, Saturn, and the Georgium Sidus.

8 Q. Are these Planets all placed at an equal Distance from the Sun?

A. They are placed at different Distances; and perform their Revolutions round it in very different Periods.

9 Q. How are the Earth and the other Planets supported?

A. They hang as it were in the Air,

without any visible Cause to support them from above, or uphold them from beneath. 10 Q. Has not the Sun any Motion then?

A. Although it always preserves its Station in the Centre of our System, yet it has a Motion on its own Axis, just like a Spinning Wheel, which keeps turning round without moving from its Place.

MERCURY.

11 Q. Which is the nearest Planet to the Sun?

A. Mercury, which performs a Revolution round it in three Months, travelling nearly as fast again as the Earth. It is so near the Sun, that its Heat is sufficient to make Water boil. It sometimes comes between us and the Sun, when it appears like a little black Spot.