Introduction . 17 
Particle of any Fluid is in itfelf as folic ! as the cles of the moil hard and confident Body whatfo - ever ; nor can any one Body be faid to be fol id one way , and another Body another way ; for the Caule that makes one fo , makes alfo the other fo , and actly in the lame Manner and Degree . Howfoever likewife any particular Parcel of Matter is managed , and although it be broke and fubtilized into Parts of the molt conceivable Smallnefs , yet it even then is as far from having in itfelf a Power of Self - motion , as it had in a much grofier Form . But as to Figure and Extenfion , or Magnitude , although there is no Body whatfoevcr but mull necefiarily be endued with them , and exift under lome Figure or other , and Degree of Extenfion , yet they may be very ferent in one Body from what they are in another ; and from the continual Occurfions and Attradlions of moving Bodies , we find them continually fubjcét to Changes ; the Points of fome being ftruck off , whereby they lofe both their former Figure and Bulk , and others by their mutual Gravitations or tractions towards one another , cohere and form Cor - pufcles of new Shapes and Dimenfions . 
Thus farther , as Figure and Magnitude are the only efiential Properties which can be diverfify'd , fo from their different Modifications , with Motion , refultsall that Variety of Forms and Appearances under which the material World does exiit : For if the other ef - fential Properties will admit of no Variation , then it necefiarily follows , that what adventitious or dental Qualities foevcr Bodies appear to be endued with , they are owing altogether to the peculiar Dif - pofitions of the two former , as they happen to be wrought upon and modify'd by any external Caufe , and as thereby they are empower'd by their peculiar 1 " igures , Bulks , and Motions , either to alFeét us or other Bodies in any particular manner . 
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