VW rNTnODCCTION. 



inhabit, attended by its satellite the MooN © ; 

 beyond which is Mars J, whose deep red light 

 distinguishes him from JUPITER If., the largest in 

 reality, and the most brilliant in appearance, after 

 Venus, of them all, attended by his four satel- 

 lites. Saturn ^, marked by his double ring and 

 seven satellites, is next; and the outermost of all 

 is Uranus ^, who has six moons, and who 

 shines with a pale white light. Of the small 

 telescopic planets, JuNO 0, Ceres ^, Pallas $, 

 and Vesta ^, making their in\isible cii'cuits 

 between Mars and our Earth, I have said no- 

 thing, nor of the comets before hinted at. Suf- 

 fice it to say then, that the planets move in orbits 

 round the sun, and that the periods of each, or the 

 time of revolving from any one point in the heavens 

 to the same point again, is called their orbit. In 

 making these orbits, the planets move according 

 to some law of motion, one effect of which appears 

 to be the describing of areas equal to the times. 

 Newton has attempted to account for this on the 

 principle of attraction, and it is in strict conformity 

 to the areas described by pendulums. But attrac- 

 tion, as applied to celestial bodies, is a word without 

 meaning : we must be contented to behold the 

 order and constancy of the phenomena observed, 

 and to ascribe similar effects to similar causes, of 

 which the Deity or final cause is the source.^ 



