236 GRAVITY AND LEVITY 



NEWTON'S Work, in order to convey to the 

 Superficial reader, an idea of the doctrine of 

 gravitation : " that we may begin our reasoning 

 from what is most simple and clearest to us, 

 let us consider what is the nature of gra- 

 vity on earth, that we may consider it in the 

 heavenly bodies, situated at a vast distance. 

 It is now agreed, by all philosophers, that all 

 circumterrestrial bodies gravitate towards the 

 earth ! ! ! That no bodies really light are to be 

 found ; that what is relative levity, is not 

 true levity, but apparent only; and arises 

 from the preponderating gravity of the conti- 

 guous bodiesv Moreover, all bodies, gravitate 

 towards the earth ; so does the earth again, 

 towards those bodies. That the action of gra- 

 vity is mutual, and equal on both bodies, is 

 thus proved, Let the mass of the earth be dis- 

 tinguished into any two parts whatever, either 

 equal, or any how unequal : now if the weights 

 of the parts towards each other, were not mu- 

 tually equal, the lesser weight would give way 

 to the greater, and the two parts joined together, 

 would move, ad infinitum,in a right line towards 

 that part to which the greater weight tends : 

 which is altogether against experience. There- 

 fore, we must say, that the weights of the parts 

 are constituted in equilibrio; that is, that the ac- 

 tion of gravity is mutual and equal on both sides. 

 The weights of bodies, at equal distances from 



