Mifcellanea Curiofa. 59 



to ask cm bono, and with whom Arguments drawn 

 from Final Caufes prevail much. If this fliorc 

 Effay mail find a kind Acceptance, I (hall be en- 

 courag'd to enquire farther, and to Polifli this 

 rough Draft of a Notion till hitherto not fb much 

 as ftarted in the World, and of which we could 

 have no Intimation from any other of the Pheno- 

 mena of Nature. 



Since this was written, a Difcovery I have 

 made in the Cceleftial Motions, leems to render 

 a farther Account of the life of the Cavity of the 

 Earth, vt%. To diminifh the Specified Gravity 

 thereof, in refpeft of the Moon ; for I think I 

 can demonftrate that the Oppofition of the ./Ei- 

 ther to the Motions of the Planets in long time 

 becomes ienfible ; and confequently the greater 

 Body muft receive a lefs Oppofition than the 

 (mailer, unlefs the Specifick Gravity of the fmal- 

 ]er do proponionably exceed that of the greater, 

 in which cafe only they can move together ; fo 

 that the Cavity I affign in the Earth, may well 

 ferve to adjuft its weight to that of the Moon, for 

 otherwife the Earth would leave the Moon behind 

 it, and flie become another Primary Planet. 



An 



