The Preface. 



And on this Occafion, it will 

 be convenient to intimate to the 

 Reader ; 



Fir SI, That the Theories and 

 Difcourfes here collected, have 

 already pa ft the Cenfure of the 

 Learned World : Who have ac- 

 knowleg'd them the moft fatis- 

 fa&ory Accounts of Nature's Pro- 

 ceedings, wherein fome of her 

 greateft Depths are fathom'd, and 

 a Foundation laid for Pofteriry to 

 build an infinite SuyerftruBure. 



Secondly, That they are related 

 (Verbatim)]^ as they were delive- 

 red in, or read before the Royal 

 Society : For it has been the Opi- 

 nion of the moft Judicious among 

 thofe Honourable Members, that it 

 is impoflible fo to abridge them, 

 (which are but Abridgments 

 themfelves) as not to render them 

 obfcure and unintelligible. 



A 



