ELEMENTS OF SCIENCE. 



MECHANICS. 



OF MATTER AND ITS PROPERTIES. 



Matter, substance, or body, is a mode of exist- 

 ence distinguished by its possessing certain known 

 properties, by which it is rendered evident to our 

 senses. 



Some sorts of matter are visible, or capable of 

 being seen; as wood, stone, &c. ; which depends 

 upon the property they have of not permitting the 

 rays of light to pass through them, the rays being 

 reflected to our eyes, as will be seen when we come 

 to treat of optics. 



Other bodies are always invisible, on account of 

 their perfect transparency; such as the atmo- 

 spheric air by which we are surrounded, which, 

 though perfectly invisible when dry and pure, yet 

 is substance or matter, as much as the hardest 

 stone. 



The existence of other species of matter is still 

 more difficult to perceive, being ascertained only 



VOL. I. k 



