178 



MAGNETISM AND ELECTRICITY 



with the other blue print. Notice that the lines of force, 

 as the filing are said to indicate, seem to push against 

 one another in (a) and pull upon one another in (b). 



So far we have noticed that magnets attract iron. 

 Now we are going to learn about the effect which two 

 magnets have upon each other. 



Experiment 76. Attraction and Repulsion. 

 Apparatus: Two bar magnets, stand. 

 Materials : Thread, heavy paper, 

 a. Make a support for one magnet from the paper 



and hang it up by 

 the thread, as shown 

 i n the illustration. 

 The thread will un- 

 twist but the magnet 

 will finally come to 

 rest. Then bring up 

 one pole of the other 

 magnet to one pole of 

 the supported mag- 

 net. What happens? 

 The magnets have 

 their north poles marked. Which poles caused the 

 result? Now bring the other pole to the same pole of 

 the supported magnet and tell what happens. As we 

 have learned, if the poles come together it shows attrac- 

 tion ; if they go away from each other we call it repul- 

 sion. What is the rule for attraction and repulsion? 



