18 THE FIXED STARS. 



are very irregular. It is supposed that there are at 

 least a thousand comets belonging to our system. 



THE FIXED STARS. 



The other heavenly bodies which are seen in 

 the firmament are called fixed stars. The num- 

 ber of stars which may be seen at any time by the 

 naked eye is not much above one thousand ; but 

 44,000 have been discovered by the aid of the 

 telescope. These stars have been arranged by 

 astronomers into various collections called constel- 

 lations, and names are given to them, as, the great 

 bear, the virgin, the scales, &c. All these constel- 

 lations are delineated on the celestial globe. 



Questions. 



How many primary planets are there! 

 What are their names ? 

 Which of them is nearest to the sun ? 

 Which is the next? 

 For what is Venus remarkable ? 

 What other names are given to this planet 1 

 What is the diameter of the earth ? 

 In what time does it make its journey round the sun? 

 What do we call that period of time 1 

 How does the moon move! 

 Is it larger or smaller than the earth ? 

 Which is the next of the planets ? 

 What is the size of Mars 1 * 



Which are the lately discovered planets ? 

 Which is the largest of them ? 

 What is its diameter? 



Which is the largest of the planets of the solar system? 

 For what is it remarkable ? 

 How far is Saturn distant from the sun 1 



