ASTRONOMY. 



235 



orbits than the Earth they bear the names of superior planets. The 

 Earth has one, Jupiter four, Saturn seven, and Uranus six moons ; 

 these are called Satellites, and they are denominated secondary planets. 

 At the same time that the Planets perform their revolutions round the 

 Sun (by which the period of their year is regulated), they also revolve 

 round their own axis, and by these means they have a succession of 

 day and night. 



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