Introduction . 1 . 3 
Reft , remain a Void , and into which any other Body , not exceeding its Dimenfions , may enter without any manner of Protruiion or Rcfiitancc . 
However any rational Creature came fo far to im - pofe upon himfelf , as to entertain a Di { belief hereof , I cannot eafdy imagine . But it is certain , that fuch have been the Prejudices which fome Perfons have taken up from an unaccountable Bigotry to Syfte - matical Learning , and to thofe Hypothefes larly which have had the Maidenhead of their Un - derftandings , as to have railed Controverfies on . Some with their Heads full ot the Tricks ot a fubtle Matter , and others , out of a religious Dread of charging fuch an odious Thing as a Vacuum upon ture , have not made any Difficulty fometimes of guing themfelvcs out of their Senfes . For fuch as have not quite outgone all Regard to their Teil i mo ny , cannot but be fully convinced , as well as from Rea - fon , by an Abundance of convincing Experiments ( for this Purpofe contrived ) of the Truth hereof : Although in this Idea there may indeed be made fome Diftin & ion from thofe before taken Notice of , viz . That it is rather from a privative , than a pofitive Caufe : But ( as the excellent Mr Locke hath already made it fully appear ) nothing is more certain , than that we have a great many of our pofitive Ideas or Perceptions even very clear and diltindt from vate Caufes , as of Refi , Silence , a Shadow , and many others . But for a full Account of the fophi - ftical Reafonings , by which lome have endeavoured to impofe both upon themfelvcs and others herein , with a full refutation of them , the Reader may confult Borelli de Motibus naturalibus à Gravitate Pen~ dentibus , Prop . 247 , —270 , and Mr John Keil' / cond Lefìure , in his Introducilo ad Veram Pby / tcarn . 
There is another Idea likewife , which we obtain from our Senfes of the Properties of Matter , and 
2 which