I.-FHYSICS. 



CHAPTER I, 



ATOMS AND ATTRACTION. 



Of what is 1* ATOMS. All matter is supposed to be 



matter compo- composed of exceedingly minute spherical 



sed? What , 



is said of or spheroidal particles, which are held to- 

 gether by their mutual attraction, and are 

 never themselves subdivided. These particles are com- 

 monly called atoms. There is reason to believe that 

 the atoms of different substances differ from each other 

 in weight and perhaps in size. The belief that they 

 are never subdivided is not based on their extreme 

 minuteness, but on other grounds, to be mentioned 

 hereafter. 



2. MINUTENESS OF ATOMS. Their mi- 



How is the mi- 



nutcnessofat- nuteness is shown by the fact that a sin- 



oms shown? glg gmin Qf mugk wm fiu ft rOQm with 



its fragrant particles for years, without suffering any 

 considerable loss of weight. The number of atoms it 

 gives off during that time is beyond computation. 



4. ELEMENTS. There are at least sixty 



Define and il- W ; " , 



lustrate an ele- different kinds of matter. Each kind which 



cannot be separated into other kinds is called 



an elementary substance, or simply an element. Iron 



