OF MATTER AND ITS PROPERTIES. O 



instances of the extreme minuteness of the ulti- 

 mate atoms of matter. 



A sino-le grain of musk will fill for several years 

 with its odour an apartment where the air is otten 

 renewed; and if we consider that the musk must 

 send off particles continually to mix with every 

 part of the air of the apartment, it will be readily 

 perceived, that they must be inconceivably minute. 



The particles of light also, as will be more par- 

 ticularly explained when we treat of optics, must 

 be small beyond all conception. 



Mobility means that property by which matter 

 is capable of being moved from one part of space 

 to another. 



Extension has, by some, been considered as a 

 distinguishing property of matter; but as space is 

 also extended, this cannot be reckoned a charac- 

 teristic. Mere space differs essentially from matter, 

 having no other property except extension: it may 

 be resolved into parts by the mind, but these parts 

 are not capable of actual separation from each 

 other, and it cannot give any resistance to bodies 

 moving through it. 



Besides these, matter possesses a property which 

 is called inertia, or inactivity j by which it would 

 always continue in whatever state it was put, 

 whether of rest or motion, unless prevented by 

 some external force. 



Most of the bodies with which we are generally 

 acquainted are capable of existing in two distinct 

 states; viz. that of solidity and fluidity. 



In solids, the parts cohere together, and the 

 body must be moved in a mass: a block of stone 

 and a piece of wood are familiar instances. 



In fluids, the particles are but weakly con- 

 nected, their mutual cohesion being in a great 



b 3 



