4 Preliminary Remarks. 



examples of a division carried to a still greater extent in odours, 

 the sense being affected in this case by particles proceeding 

 from the odoriferous body that are absolutely invisible and 

 impalpable. From these - few instances, and a thousand others 

 that might be mentioned, it is evident that a body without chang- 

 ing its character, without ceasing to be of the same identical 

 nature with the largest masses that surround us, may be divided 

 into parts, the smallness of which eludes the power of the senses, 

 and almost that of the imagination. 



6* The question has been much discussed, whether matter 

 by infinitely divisible ; but it is now pretty generally agreed 

 that the dispute is about words. If the point in question relate 

 to abstract geometrical divisibility, there can be no doubt of the 

 truth of the affirmative ; for however infinitely small we suppose 

 a particle, from the very circumstance of its being extended, we 

 can always conceive this extent divided into two halves, and 

 each of these into two others, and so on without end (Calc. 4). But 

 if we mean by the question an actual physical divisibility, nothing 

 can be decided absolutely one way or the other. It seems however 

 by all we can learn, that we should at some stage of the division 

 arrive at material particles which would not admit of being brok- 

 en, or altered, or transmuted the one into the other ; for to what- 

 ever chemical operation they are subjected, into whatever com- 

 binations they are made to enter, however they may be brought 

 to constitute a part of living beings, they always return to their 

 former state, with their original properties unchanged. The 

 infinite variety of processes of this kind through which the same 

 material particles have been made to pass since the world was 

 created, does not appear to have produced the smallest alteration, 



7, But how can such a system of particles exist collected 

 together in the form of solid and resisting masses, as we see they 

 are. in a great number of Bodies, in all indeed when they are 

 properly examined ? This state, as we shall see hereafter, is pro- 

 duced and maintained by the natural powers with which all 

 parts of matter are endued, and which cause them to tend to- 

 ward each other, as it were by an attraction. But if there existed 

 only forces of this kind, the particles would continue to approach 

 till they came into actual contact with each other, that is, until 

 they were arrested by the impenetrability of their parts, which 

 would not admit of the contraction and dilatation which are con- 



