252 Astronomy, [Lecture IT. 



as a science, by the system of Copernicus*, pub- 

 lished at Nuremberg in 1543, and afterwards 

 brought to perfection by Kepler, Galileo, and 

 Newton : a system so bold and daring, that it 

 produced general astonishment, and yet its truth 

 has been confirmed by the observations of every 

 succeeding age. 



The surface of the heavens seems to us to be 

 studded with stars ; between the fixed stars and 

 us there seem to be other stars which change 

 their situations respectively one towards another, 

 and these all astronomers have agreed in calling 

 planets^ or wandering stars. 



The antient philosophers, who knew very 

 little even of the movements of the planets, had 

 no means of knowing the true disposition of 

 their orbits ; and this is the reason they vary so 

 greatly in their opinions. They supposed, at 

 first, the earth to be immoveable, as the centre 

 of the universe, and that all the celestial bodies 

 turned about her; which, indeed, was natural 

 for them to believe, without having discussed the 

 proofs to the contrary. 



It is asserted, however, that the Babylonians, 

 and afterwards Pythagoras and his disciples, 

 considered the earth as a planet, and the sun 

 as immoveable, and the centre of our planetary 

 system. 



Plato is said to have been the reviver of the 

 system of the immobility of the earth ; and many 

 * Born at Thorn, in Royal Prussia, in 1472- 



