ASTRONOMY. 423 



the Georgian planet, which seem to move in a 

 contrary direction. The paths in which they 

 move round the sun is called their orbits. These 

 orbits are elliptical, but the eccentricity of the 

 ellipses is so small, that they approach very nearly 

 to circles. They perform their revolutions also in 

 very different periods of time. The time of per- 

 forming their revolutions is called their year. 



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