1 2 Matter and Motion. 



Motion is so well known by the sight 

 and touch, that to use words to give a 

 clearer idea of it would be in vain. 



Matter, or body, is indifferent to mo- 

 tion or rest. 



There is as much force required to 

 put a body, which is in motion, at rest ; 

 as there is to set a body, which is at rest, 

 into motion. 



No parcel of matter can give itself ei- 

 ther motion or rest ; and therefore a bo- 

 dy at rest will remain so eternally, ex- 

 cept some external cause puts it in mo- 

 tion ; and a body in motion will move 

 eternally, except some external cause 

 stops it. 



A body in motion will always move 

 on in a straight line, unless it be turned 

 out of it by some external cause ; because 

 a body can no more alter the determina- 

 tion of its motion than it can begin it, 

 alter or stop its motion itself. 



The velocity of motion is estimated 

 by the time employed in moving over a 

 certain space, or by the space moved 

 over in a certain time. The less the time, 

 and the greater the space moved over, the 

 greater is the velocity ; on the contrary, 



