jo Introduction . 
cite in every one that attends to them , the fame Ideas - , and this Way we come by very clear and diftind Ideas oí " Solidity , Extcnfion , and Figure . 
In every Body or Parcel of Matter , under what - foever Mode of Exiftence , we immediately find in it a Power of Hcf» ( lance , fo as not to admit any Other Body in its Place , unlefs by any external Force it felf be firft removed out of it . This we find ne - ceífarily and univerfally to hold good in all Bodies , both fluid and folid . For although the conftituent Pans may be fitted never fo much to form a ing fluxile Body i yet when the Mind confiders it only as it is Matter , or fomething corporeal , and purlues it to its fmalleft conftituent Parts , it will appear itili with the fame Neceffity to be endued with this Property , as much as if it was the moil firm and confident Compofition of Matter whatfo - ever . Thus the Air enclofed in a Bladder , as much refills the Sides of it , being brought to a clofe Con - ta<5t , by any external Preflure , as this book between my Hands prevents their touching one another . And this is the very fame which fome pleafe to call penetrability ; which is to fay , that every Body or parcel of Matter is fo folid , as not by any Means whatfoevcr to allow of another Body's being thruft jnto , and poflefling the fame Place which that takes lip , before it is firft thruft out , and thereby makes Room for the other's coming into it . 
Extenfion alfo appears with as much Clearnefs and Convi & ion to be another Property • , altho' not As Solidity , which can be applicable to nothing elfe , becaufe , as will farther appear a little below , it is eafy to conceive of an abfolutely extended Space that is empty of all Body , or which is the lame thing , a cominenfurable Diftance between two dies that are remote from each other , and yet have another Body between them : Although indeed the 
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